Clethodim 11 mars 2016 Proposed Re-evaluation Decision

Clethodim 11 mars 2016  Proposed Re-evaluation Decision
Proposed Re-evaluation Decision
PRVD2016-11
Clethodim
11 mars 2016
(publié aussi en français)
This document is published by the Health Canada Pest Management Regulatory Agency. For further
information, please contact:
Publications
Pest Management Regulatory Agency
Health Canada
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A.L. 6607 D
Ottawa, Ontario K1A 0K9
Internet:
pmra.publications@hc-sc.gc.ca
healthcanada.gc.ca/pmra
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ISSN:
1925-0959 (print)
1925-0967 (online)
Catalogue number:
H113-27/2016-11E (print)
H113-27/2016-11E-PDF (PDF version)
© Her Majesty the Queen in Right of Canada, represented by the Minister of Health Canada, 2016
All rights reserved. No part of this information (publication or product) may be reproduced or transmitted in any form or by any
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permission of the Minister of Public Works and Government Services Canada, Ottawa, Ontario K1A 0S5.
Table of Contents
Overview ......................................................................................................................................... 1 What Is the Proposed Re-evaluation Decision? .......................................................................... 1 What Does Health Canada Consider When Making a Re-evaluation Decision? ....................... 1 What Is Clethodim? .................................................................................................................... 2 Health Considerations ................................................................................................................. 2 Risks in Residential and Other Non-Occupational Environments .............................................. 3 Environmental Considerations .................................................................................................... 4 Value Considerations .................................................................................................................. 5 Next Steps ................................................................................................................................... 6 Science Evaluation .......................................................................................................................... 7 1.0 Introduction ......................................................................................................................... 7 2.0 The Technical Grade Active Ingredient, Its Properties and Uses ....................................... 7 2.1 Identity of the Technical Grade Active Ingredient. ........................................................ 7 2.2 Physical and Chemical Properties of the Technical Grade Active Ingredient ................ 8 2.3 Description of Registered Clethodim Uses ..................................................................... 8 3.0 Impact on Human Health .................................................................................................... 9 3.1 Toxicology Summary...................................................................................................... 9 3.1.1 Pest Control Products Act Hazard Consideration .................................................... 11 3.2 Occupational and Non-Occupational Exposure and Risk Assessment ......................... 12 3.2.1 Toxicological Endpoints ........................................................................................... 12 3.2.2 Occupational Exposure and Risk Assessment .......................................................... 13 3.3 Dietary Exposure and Risk Assessment ....................................................................... 14 3.3.1 Determination of Acute Reference Dose (ARfD) ..................................................... 15 3.3.2 Acute Dietary Exposure and Risk Assessment ......................................................... 16 3.3.3 Determination of Acceptable Daily Intake (ADI) .................................................... 16 3.3.4 Chronic Dietary Exposure and Risk Assessment...................................................... 16 3.3.5 Dietary Cancer Exposure and Risk Assessment ....................................................... 17 3.4 Exposure from Drinking Water .................................................................................... 17 3.4.1 Concentrations in Drinking Water ............................................................................ 17 3.4.2 Drinking Water Exposure and Risk Assessment ...................................................... 17 3.5 Aggregate Exposure and Risk Assessment ................................................................... 18 3.6 Cumulative Risk Assessment ........................................................................................ 18 4.0 Impact on the Environment ............................................................................................... 18 4.1 Fate and Behaviour in the Environment ....................................................................... 18 4.2 Environmental Risk Characterization ........................................................................... 19 4.2.1 Risks to Terrestrial Organisms.................................................................................. 20 4.2.2 Risks to Aquatic Organisms...................................................................................... 22 5.0 Value ................................................................................................................................. 23 6.0 Pest Control Product Policy Considerations ..................................................................... 24 6.1 Toxic Substances Management Policy Considerations ................................................ 24 6.2 Formulants and Contaminants of Health or Environmental Concern ........................... 24 7.0 Incident Reports ................................................................................................................ 25 8.0 Organisation for Economic Co-operation and Development Status of Clethodim........... 25 Proposed Re-evaluation Decision – PRVD2016-11
9.0 Proposed Re-evaluation Decision ..................................................................................... 26 9.1 Proposed Regulatory Actions ....................................................................................... 26 9.1.1 Proposed Regulatory Action Related to Human Health ........................................... 26 9.1.2 Proposed Regulatory Action Related to the Environment ........................................ 26 10.0 Supporting Documentation ............................................................................................... 27 List of Abbreviations .................................................................................................................... 29 Appendix I Clethodim Products Registered in Canada as of 29 January 20141 ...................... 33 Appendix II Clethodim Uses Registered in Canada as of 29 January 2014.............................. 35 Appendix III Toxicology Endpoints for Health Risk Assessments ........................................ 39 Table 1 Toxicity profile of clethodim .................................................................................... 39 Table 2 Toxicology Endpoints for Use in Health Risk Assessment for Clethodim .............. 48 Appendix IV Agricultural Mixer/Loader/Applicator and Postapplication Risk
Assessment ........................................................................................................ 49 Table 1 Occupational Mixer/Loader/Applicator Exposure and Risk Assessment (Baseline
PPE) .......................................................................................................................... 49 Table 2 Postapplication Exposure and Risk Assessment ....................................................... 50 Table 3 Summary of Transfer Coefficient for Clethodim...................................................... 50 Appendix V Dietary Exposure and Risk Estimates for Clethodim .......................................... 53 Table 1 Summary of Acute Dietary Exposure and Risk from Clethodim ............................. 53 Table 2 Summary of Chronic Dietary Exposure and Risk from Clethodim .......................... 53 Table 3 Dietary Input Characterization for Clethodim .......................................................... 53 Appendix VI Food Residue Chemistry Summary .................................................................. 61 Appendix VII Supplemental Maximum Residue Limit Information – International Situation and
Trade Implications ................................................................................................ 63 Table 1 Comparison between MRLs in Canada and in Other Jurisdictions .......................... 63 Table 2 Residue Definition in Canada and Other Jurisdictions ............................................. 67 Appendix VIII Environmental Risk Assessment....................................................................... 69 Table 1 Physical and chemical properties of clethodim ........................................................ 69 Table 2 Table of maximum formation of transformation products ....................................... 70 Table 3 Fate and behaviour in the environment of clethodim technical grade active
ingredient and its major transformation products clethodim sulfoxide, clethodim
sulfone, clethodim oxazole sulfone and clethodim imine ......................................... 73 Table 4 Toxicity of clethodim and transformation products to Non-Target terrestrial
Species ...................................................................................................................... 80 Table 5 Screening level and refined risk assessment of clethodim to beneficial arthropods. 86 Table 6 Screening level risk assessment of clethodim to earthworms, bees and terrestrial
vascular plants ........................................................................................................... 88 Table 7 Estimated Environmental Concentrations (EEC) in vegetation and insects ............. 88 Table 8 Further characterization of risk to Terrestrial Vascular Plants ................................. 89 Table 9 Screening level risk assessment of clethodim to birds and mammals ...................... 89 Table 10 Toxicity of clethodim and end-use products to Non-Target aquatic Species ....... 90 Table 11 Screening level risk assessment of clethodim and transformation products for
aquatic organisms.................................................................................................. 93 Table 12 Risk Quotients for aquatic organisms determined for drift of clethodim ............. 95 Proposed Re-evaluation Decision – PRVD2016-11
Table 13 Risk Quotients for Aquatic Organisms Determined for Runoff of clethodim in
Water Bodies 80 or 15 cm deep ............................................................................ 95 Appendix IX Proposed Label Amendments for Products Containing Clethodim .................. 97 References ................................................................................................................................... 103 Proposed Re-evaluation Decision – PRVD2016-11
Overview
What Is the Proposed Re-evaluation Decision?
After a re-evaluation of the herbicide clethodim, Health Canada’s Pest Management Regulatory
Agency (PMRA), under the authority of the Pest Control Products Act and Regulations, is
proposing continued registration of products containing clethodim for sale and use in Canada.
An evaluation of available scientific information found that currently registered uses of
clethodim products do not pose unacceptable risks to human health or the environment when
used according to the proposed label directions. As a requirement of the continued registration
for these clethodim uses, new risk-reduction measures are proposed for the end-use products
registered in Canada. No additional data are being requested at this time.
This proposal affects the end-use products containing clethodim registered in Canada. Once the
final re-evaluation decision is made, registrants will be instructed on how to address any new
requirements.
This Proposed Re-evaluation Decision is a consultation document1 that summarizes the science
evaluation for clethodim and presents the reasons for the proposed re-evaluation decision. It also
proposes new risk-reduction measures to further protect human health and the environment.
This consultation document is presented in two parts. The Overview describes the regulatory
process and key points of the evaluation, while the Science Evaluation provides detailed
technical information on the assessment of clethodim.
The PMRA will accept written comments on this proposal up to 60 days from the date of
publication of this document. Please forward all comments to Publications (please see contact
information indicated on the cover page of this document).
What Does Health Canada Consider When Making a Re-evaluation Decision?
The PMRA’s pesticide re-evaluation program considers potential risks, as well as value, of
pesticide products to ensure they meet modern standards established to protect human health and
the environment. Regulatory Directive DIR2012-02, Re-evaluation Program Cyclical Reevaluation, presents the details of the cyclical re-evaluation approach.
For more details on the information presented in this Overview, please refer to the Science
Evaluation of this consultation document.
1
“Consultation statement” as required by subsection 28(2) of the Pest Control Products Act.
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What Is Clethodim?
Clethodim is a selective systemic grass herbicide. It is registered for post-emergent control of
grassy weeds on a variety of broadleaved crops. Clethodim products are formulated as
emulsifiable concentrate or emulsion and can be applied using ground or aerial equipment. The
rate of application ranges from 15.1 to 91.2 g a.i./ha, depending upon the types of crops it is used
on.
Health Considerations
Can Approved Uses of Clethodim Affect Human Health?
Products containing clethodim are unlikely to affect your health when used according to
proposed label directions.
Potential exposure to clethodim may occur through diet (food and water) or when handling and
applying products containing clethodim. When assessing health risks, two key factors are
considered: the levels where no health effects occur, and the levels to which people may be
exposed. The dose levels used to assess risks are established to protect the most sensitive human
population (for example, children and nursing mothers). Only uses for which the exposure is well
below levels that cause no effects in animal testing are considered acceptable for registration.
Toxicology studies in laboratory animals describe potential health effects from varying levels of
exposure to a chemical and identify the dose where no effects are observed. The health effects
noted in animals occur at doses more than 100 times higher (and often much higher) than levels
to which humans are normally exposed when pesticide-containing products are used according to
label directions.
In laboratory animals, clethodim was of low to slight acute oral toxicity, and of low toxicity via
the dermal and inhalation routes. Clethodim was mildly irritating to the eyes and skin, and did
not cause an allergic skin reaction.
Short- and long-term (lifetime) animal toxicity tests, as well as published reviews from other
regulatory agencies, were assessed for the potential of clethodim to cause neurotoxicity,
immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various
other effects. The most sensitive endpoint used for risk assessment was effects on the liver.
There was no indication that the young were more sensitive than the adult animal. The risk
assessment protects against these and any other potential effects by ensuring that the level of
exposure to humans is well below the lowest dose at which these effects occurred in animal tests.
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Residues in Food and Drinking Water
Dietary risks from food and water are not of concern.
Reference doses define levels to which an individual can be exposed over a single day (acute) or
lifetime (chronic) and expect no adverse health effects. Generally, dietary exposure from food
and water is acceptable if it is less than 100% of the acute reference dose or chronic reference
dose (acceptable daily intake). An acceptable daily intake is an estimate of the level of daily
exposure to a pesticide residue that, over a lifetime, is believed to have no significant harmful
effects.
Acute and chronic dietary exposures to clethodim were estimated from residues of clethodim in
treated crops and drinking water for different subpopulations including children and women of
reproductive age. A cancer risk assessment was not required as there was no evidence of
carcinogenicity.
The acute dietary exposure estimate (in other words, from food and drinking water) at the 95th
percentile represents 3.6% of the acute reference dose (ARfD) for the general population and
ranges from 2.4% of the ARfD (for adults 50-99) to 7.2% of the ARfD (for children 1-2 years
old) for all other population subgroups when using drinking water concentrations generated from
water modelling. The chronic dietary exposure estimate for the general population represents
8.7% of the acceptable daily intake (ADI) and ranges from 6.9% of the ADI (for adults 50-99) to
24.3% of the ADI (for children 1-2 years old). Thus, acute and chronic dietary risks are not of
concern.
The Food and Drugs Act prohibits the sale of adulterated food; that is, food containing a
pesticide residue that exceeds the specified maximum residue limit (MRL). Pesticide MRLs are
specified for Food and Drugs Act purposes through the evaluation of scientific data under the
Pest Control Products Act. Each MRL value defines the maximum concentration in parts per
million (ppm) of a pesticide allowed in/on certain foods. Food containing a pesticide residue that
does not exceed the specified MRL does not pose a health concern. Canadian MRLs are
currently specified for some commodities (http://pr-rp.hc-sc.gc.ca/mrl-lrm/index-eng.php).
Residues in all other agricultural commodities, including those approved for treatment in Canada
but without a specific MRL, are regulated under subsection B.15.002(1) of the Food and Drug
Regulations, which requires that residues not exceed 0.1 ppm. No changes are proposed to the
current MRLs for clethodim. For supplemental MRL information regarding the international
situation and trade implications, refer to Appendix VII of this document.
Risks in Residential and Other Non-Occupational Environments
Non-occupational risks are not of concern.
Clethodim is not registered for use in residential areas.
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Occupational Risks From Handling Clethodim
Occupational risks to handlers are not of concern when used according to proposed label
directions.
Risks to handlers are not of concern for all scenarios. Based on the precautions and directions for
use on the original product labels reviewed for this re-evaluation, risk estimates associated with
mixing, loading, and applying activities exceeded target dermal and inhalation margins of
exposure (MOEs) and are not of concern.
Postapplication risks are not of concern for all uses.
Postapplication occupational risk assessments consider exposures to workers entering treated
sites in agriculture. Based on the current use pattern for agricultural scenarios reviewed for this
re-evaluation, postapplication risks to workers performing activities, such as scouting, exceeded
target dermal MOEs and are not of concern. A standard restricted entry interval of 12 hours is
proposed for agricultural sites.
Environmental Considerations
What Happens When Clethodim Is Introduced Into the Environment?
When used according to proposed label directions, products containing clethodim are not
expected to pose an unacceptable risk to the environment.
When clethodim is released into the environment, it can enter soil and surface water. In soil,
clethodim breaks down quickly, and therefore, it is not expected to move downward through the
soil and enter groundwater. In aquatic environments, clethodim is slightly persistent. Clethodim
is not expected to accumulate in the environment or in the tissues of organisms. The major
breakdown products of clethodim (clethodim sulfoxide and clethodim sulfone) are slightly
persistent and highly mobile in soil and are expected to reach groundwater. However,
groundwater modelling based on chemical fate data and conservative assumptions indicate that
clethodim sulfoxide and clethodim sulfone will not enter groundwater at levels that could pose
unacceptable risks to human health or the environment.
Clethodim does not pose a significant risk to most terrestrial organisms (earthworms, bees, birds
and mammals). If clethodim is used at labelled application rates without any risk reduction
measures, it may cause adverse effects on plants, certain beneficial insects and aquatic organisms
(freshwater invertebrates and amphibians). Therefore, mitigation measures in the form of spray
buffer zones and hazard statements are required in order to reduce potential exposure of nontarget organisms. When used according to proposed label directions, clethodim is not expected to
pose an unacceptable risk to the environment.
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Value Considerations
Clethodim contributes to weed management in many important crops grown in Canada
when used in accordance with label directions.
Clethodim is a useful herbicide for Canadian producers due to its selectivity for annual and
perennial grasses along with its tolerance by broadleaved crops. It is applied post emergence to
weeds and crops and can be tank mixed with many other herbicides. It is one of the broadest
spectrum grass herbicides available to Canadian growers and one of few grass herbicides
providing effective control of perennial grassy weeds. It is widely used in a variety of important
crops grown in Canada such as canola, pulses and other oilseed crops. Clethodim is registered
for use on many minor use crops and is the only herbicide registered on Prairie carnation. It is
the only alternative grass herbicide to sethoxydim in many minor use crops. Clethodim has also
been identified as a priority by Canadian growers for many commodities.
Proposed Measures to Minimize Risk
Labels of registered pesticide products include specific instructions for use. Directions include
risk-reduction measures to protect human health and the environment. These directions must be
followed by law. As a result of the re-evaluation of clethodim, the PMRA is proposing further
risk-reduction measures in addition to those already identified on product labels. Additional
proposed risk-reduction measures are discussed below.
Human Health
To protect applicators:
 Additional label statements to clarify the protective equipment for workers applying
clethodim.
To protect workers entering treated sites:
 Clarification that clethodim is not registered for use in greenhouses.
To protect bystanders from spray drift:
 A statement to promote best management practices to minimize human exposure from
spray drift or spray residues resulting from drift.
Environment
To protect non-target terrestrial and aquatic habitats:
 Spray buffer zones ranging from 1 to 60 meters and 1 to 10 meters to protect non-target
terrestrial and aquatic habitats, respectively, from pesticide spray drift.
 Instructions on product labels for reducing run-off.
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To protect groundwater:
 A statement on product labels informing users of the leaching potential of these
chemicals and identifying soil and water table conditions that may result in ground water
contamination (permeable soils, shallow water table).
Next Steps
Before making a final re-evaluation decision on clethodim, the PMRA will consider all
comments received from the public in response to this consultation document. A science-based
approach will be applied in making a final decision on clethodim. The PMRA will then publish a
Re-evaluation Decision2 that will include the decision, the reasons for it, a summary of
comments received on the proposed decision and the PMRA’s response to these comments.
2
“Decision statement” as required by subsection 28(5) of the Pest Control Products Act.
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Science Evaluation
1.0
Introduction
Clethodim is a herbicide registered for post-emergent control of grassy weeds on a variety of
broadleaved crops. It belongs to the cyclohexanedione chemical family and is classified as a
Weed Science Society of America Group 1 herbicide. The herbicidal activity of clethodim is due
to the inhibition of the initial enzyme in the synthesis of fatty acid, acetyl CoA carboxylase
(ACCase), used in building new membranes required for cell growth.
Following the re-evaluation announcement for clethodim, the registrants of the technical grade
active ingredient indicated their support for continued registration of all uses included on the
labels of end-use products containing clethodim in Canada. Currently registered Canadian
products containing clethodim are listed in Appendix I.
2.0
The Technical Grade Active Ingredient, Its Properties and Uses
2.1
Identity of the Technical Grade Active Ingredient.
Common name
Clethodim
Function
Herbicide
Chemical Family
Cyclohexane oxime
Chemical name
1
International Union of Pure
and Applied Chemistry
(IUPAC)
(5RS)-2-{(1EZ)-1-[(2E)-3chloroallyloxyimino]propyl}-5-[(2RS)-2(ethylthio)propyl]-3-hydroxycyclohex-2-en1-one
2
Chemical Abstracts Service
(CAS)
2-[1-[[[(2E)-3-chloro-2-propen-1yl]oxy]imino]propyl]-5-[2-(ethylthio)propyl]3-hydroxy-2-cyclohexen-1-one
CAS Registry Number
99129-21-2
Molecular Formula
C17H26ClNO3S
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Structural Formula
O
S
N
OH
O
Cl
359.9
Molecular Weight
Based on the manufacturing process used, impurities of human health or environmental concern
as identified in the Canada Gazette, Part II, Vol. 142, No. 13, SI/2008-67 (2008-06-25),
including TSMP Track 1 substances, are not expected to be present in the product.
2.2
Physical and Chemical Properties of the Technical Grade Active Ingredient
Property
Result
Vapour pressure at 20°C
< 1 × 10-2 mPa
Ultraviolet (UV) / visible
spectrum
pH
λmax (nm)
acidic 261
neutral 283
basic 283
No absorbance at λ >350 nm
Solubility in water at 20°C
13.0 mg/L (at pH 4.2)
5.45 g/L (at pH 7)
Solubility is dependent on pH
n-Octanol/water partition
coefficient at 20°C
Log Kow = 4.4; Kow = 2.5 × 104 (pH 5.35)
Dissociation constant
pKa = 4.16
2.3
Description of Registered Clethodim Uses
Appendix I lists all clethodim products that are registered under the authority of the Pest Control
Products Act as of 29 January 2014.
Appendix II lists all the Commercial Class uses for which clethodim is currently registered. All
uses were supported by the registrant at the time of initiation of re-evaluation and were,
therefore, considered in the health and environmental risk assessments. Appendix II also includes
the uses that were added through the PMRA’s User Requested Minor Use Label Expansion
(URMULE) program.
Uses of clethodim belong to the following use site categories: industrial oil seed crops and fibre
crops, terrestrial feed crops and terrestrial food crops.
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3.0
Impact on Human Health
3.1
Toxicology Summary
Clethodim is a selective cyclohexanedione herbicide which exerts its effect in plants by
inhibiting acetyl-coenzyme A carboxylase, an essential enzyme in the fatty acid biosynthetic
pathway.
A detailed review of the toxicological database for clethodim was conducted, including the more.
recent studies that assessed neurotoxicity and immunotoxicity. The scientific quality of the data
is acceptable and the database is considered adequate to define the majority of the toxic effects
that may result from exposure to clethodim.
Oral metabolism/excretion studies in the rat with radio-labelled clethodim indicated rapid
absorption and excretion. Excretion of the 14C-label primarily occurred in the urine with lesser
amounts excreted via the feces and in exhaled breath. After 7 days, the total amount of radiolabel
recovered from organs and tissues in each of the low, high and repeat dose groups was less than
1% of the administered dose. The concentration in the tissues was adrenals > liver > kidney >
bone, spinal cord, followed by the remaining tissues. The major metabolite of clethodim was
clethodim sulfoxide; in addition, smaller amounts of clethodim, clethodim sulfone, imine
sulfoxide and 5-OH sulfone were present in the tissues. A metabolic pathway was suggested in
which clethodim is rapidly oxidized to clethodim sulfoxide. Clethodim sulfoxide can be further
oxidized to clethodim sulfone, deoxyalkylated to the imine sulfoxide or hydroxylated at the 5position of the ring to yield 5-OH sulfoxide or 5-OH sulfone.
In acute toxicity testing, clethodim was of low toxicity in mice and of slight toxicity in rats by
the oral route. It was of low toxicity in rabbits by the dermal route. Clethodim was of low acute
toxicity by inhalation in rats, mildly irritating to the rabbit eye and skin, and a non-sensitizer in
guinea pigs by a modified Buehler test.
In short- and long-term dietary studies, the primary effects were on the liver and the blood. Liver
effects in short-term mouse, rat and dog studies were mostly adaptive, and included increased
liver weight, and increased centrilobular hypertrophy. In the 13-week dietary rat study, increased
liver weight and hypertrophy were reversed following a 6 week recovery period. Regenerative
anemia was noted in short-term studies with decreases in red blood cell count, hemoglobin, and
haematocrit, bone marrow hyperplasia and pigment in liver and spleen. Decreases in body
weight/body weight gain and food consumption were also noted. Repeated dermal exposure in
rats produced a similar toxicological profile as in oral studies (in other words, reduced body
weight and liver effects) in addition to dose-related skin irritation in treated animals.
Additional treatment-related effects in repeat-dose dietary studies, either at the dose levels at
which the principle effects on liver, blood and body weight first appeared, or at higher doses,
were specific to one or more species. These included focal liver coagulative necrosis at higher
doses in mice; focal kidney regeneration, increased serum uric acid and clinical chemistry
changes at the same and higher doses in rats; and centrilobular hepatocyte
vessiculation/vacuolization, bone marrow hypercellularity and clinical changes at the lowest
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observed adverse effect level (LOAEL) in dogs. At higher doses, dogs also showed increased
thyroid weight, chronic cystitis and focal haemorrhage in the bladder, and inflammation of the
vascular trunk and degenerative cardiomyopathy in the heart; clinical chemistry findings
included increased serum cholesterol, triglycerides, and alanine aminotransferase.
With chronic oral dosing, effects similar to those seen in short-term studies were observed, albeit
at lower doses, suggesting a correlation between toxicity and duration of exposure. No evidence
of carcinogenicity was seen in dietary studies in the mouse or rat. Overall, a battery of
genotoxicity tests was negative. In mice, in addition to increased centrilobular hypertrophy and
increased liver weights, there was an increased incidence and severity of amyloidosis and
regenerative anaemia with decreases in red blood cell count, haemoglobin, and haematocrit. In
rats, in addition to the liver effects, there were reductions in body weight and an increased
incidence of chronic pancreatitis.
In a dietary two-generation reproductive toxicity test, sensitivity of the young was not apparent.
Effects were limited to body weight reductions in parents and pups as well as occasional
reductions of food intake in parents. Results of oral developmental toxicity studies in the rat and
rabbit did not reveal sensitivity of the young. Rat fetuses showed signs of developmental delay at
doses affecting body weight, uterine weight and clinical signs in the dams. At a higher dose there
was an increase in external and visceral fetal malformations and an increase in maternal
mortality. In rabbits, there was a slight increase in skeletal variations in fetuses at higher dose
levels than the doses that were maternally toxic. Maternal toxicity included a reduction in body
weight gain and decreased food consumption.
In an acute oral neurotoxicity study in rats, clinical signs of toxicity included a reduction in
spontaneous activity, hunched posture, ruffled fur, abnormal gait, salivation and head tilt, and
some evidence of nerve fibre degeneration in the ventral lumbar root. Effects were only evident
at a dose that approached an acutely lethal level. Effects in the 13-week dietary neurotoxicity
study in rats were limited to reduced body weight, body weight gain, food consumption and
increased liver weight. There was an equivocal increase in minimal degeneration of the axonal
sciatic nerves in high dose males, but higher incidences of minimal sciatic nerve degeneration
were found equally in the control and high dose females. No treatment-related effects were noted
on motor activity or in functional observation battery assessments. Overall, there is weak
evidence for a neurotoxic effect.
In a 28-day dietary immunotoxicity study in mice there was equivocal evidence for an
immunotoxic effect based on non-statistically significant reductions in spleen weight and
antibody response. Similar effects were not observed in the range-finding study with comparable
dose levels. Increased liver weight was observed in both studies.
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Several toxicity studies were conducted with select plant metabolites of clethodim. In acute
gavage toxicity tests, imine sulfone and 5-OH sulfone were less acutely toxic than clethodim. In
5-week dietary toxicity studies with these two metabolites, no toxic effects were noted with 5OH sulfone, while several effects were noted at the high dose with imine sulfone (reduced body
weight gain and food consumption during the first week, increased reticulocytes, cholesterol and
liver weight). Supplementary developmental toxicity studies did not identify potential
developmental effects for either metabolite.
Genotoxicity studies involving these metabolites, which included reverse mutation tests with
strains of Salmonella typhimurium, and a chromosome aberration test with Chinese hamster
ovary (CHO) cells, were negative with both imine sulfone and 5-OH sulfone.
3.1.1
Pest Control Products Act Hazard Consideration
For assessing risks from potential residues in food or from products used in or around homes or
schools, the Pest Control Products Act requires the application of an additional 10-fold factor to
threshold effects to take into account completeness of the data with respect to the exposure of,
and toxicity to, infants and children, as well as potential pre- and post-natal toxicity. A different
factor may be deemed appropriate on the basis of reliable scientific data.
The toxicity database is currently considered complete. The database for clethodim contains a
full complement of required studies including developmental toxicity studies in rats and rabbits
and a reproductive toxicity study in rats. With respect to potential pre- and post-natal toxicity,
none of the three studies showed sensitivity of the young. In the rat developmental toxicity study,
increases in skeletal variations in the fetuses and a decrease in fetal weight, occurred at a dose at
which maternal toxicity, including decreases in body weight and increased clinical signs of
toxicity, also occurred. At the highest dose at which malformations occurred in the fetuses, there
was severe maternal toxicity with marked clinical signs, decreased body weight and mortality,
indicating an excessive dose was employed. In the rabbit developmental toxicity study, maternal
effects, in the form of a slight decrease in body-weight gain, occurred at a lower dose than fetal
effects. At a higher dose there was clear maternal toxicity (decreased body-weight gain, food
consumption and food efficiency) and slight fetotoxicity (slight increase in skeletal variations).
In the rat reproductive toxicity study, a decrease in body weight in parents and pups occurred
during the latter part of lactation at the same dose level.
Overall, the database is adequate for determining the sensitivity of the young. The fetal effects
observed were either minor in the presence of minor maternal toxicity, or, in the case of more
severe effects, did not occur except in the presence of severe maternal toxicity. Therefore, the
Pest Control Products Act factor was reduced to 1-fold for both acute and repeat exposure
scenarios.
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3.2
Occupational and Non-Occupational Exposure and Risk Assessment
Occupational and non-occupational risk is estimated by comparing potential exposures with the
most relevant endpoint from toxicology studies to calculate a margin of exposure (MOE). This is
compared to a target MOE incorporating uncertainty factors protective of the most sensitive
subpopulation. If the calculated MOE is less than the target MOE, it does not necessarily mean
that exposure will result in adverse effects, but mitigation measures to reduce risk would be
required
3.2.1
Toxicological Endpoints
3.2.1.1 Toxicology Endpoint Selection for Occupational and Non-Occupational Risk
Assessment
Short- and intermediate-term dermal risk assessment
The 28-day dermal rat study with a systemic no observed adverse effect level (NOAEL) of 100
mg/kg bw/day was selected for risk assessment. At the lowest observed adverse effect level
(LOAEL) of 1000 mg/kg bw/day, an increased incidence of urogenital discharge, increased liver
weights, and decreased body weight were noted. For the dermal route of exposure, a target MOE
of 100 was selected. Standard uncertainty factors of 10-fold for interspecies extrapolation and
10-fold for intra-species variability were applied.
Short- and intermediate-term inhalation risk assessment
The 90-day dietary rat study with a NOAEL of 25 mg/kg bw/day was selected for risk
assessment. At the LOAEL of 134 mg/kg bw/day, increased incidence of centrilobular liver
hypertrophy and focal regeneration of the kidney were observed. An oral study was used for
inhalation risk assessments because no route-specific inhalation toxicity studies were available.
For the inhalation route of exposure, a target MOE of 100 was selected. Standard uncertainty
factors of 10-fold for interspecies extrapolation and 10-fold for intra-species variability have
been applied.
3.2.1.2 Aggregate Risk Assessment
Clethodim is not registered for residential or non-occupational uses, therefore, the aggregate risk
assessment considered exposure from food and drinking water only (please refer to Section 3.5).
3.2.1.3 Cancer Assessment
There was no evidence of carcinogenicity and therefore, no cancer risk assessment is necessary.
3.2.1.4 Dermal Absorption
A dermal absorption value was not required as a dermal endpoint was selected for the dermal
route of exposure.
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3.2.2
Occupational Exposure and Risk Assessment
Workers can be exposed to clethodim through mixing, loading, or applying the pesticide, and
when entering a treated site to conduct activities such as scouting.
Mixer, Loader, and Applicator Exposure and Risk Assessment
There are potential exposures to mixers, loaders, and applicators. The following scenarios were
assessed:
•
•
•
•
•
•
Mixing/loading liquids;
Groundboom application to alfalfa seedling, beans (dry), blueberry (high bush), canola,
chickpea, coriander, cranberry, fenugreek, flax, lentil, mustard, onions, pea, potato,
prairie carnation, safflower, soybean, spinach, sunflower;
Aerial application to beans (dry), canola, chickpea, flax, lentil, mustard, pea, potato,
soybean, sunflower;
Mixing/loading/application by manually pressurized handwand to blueberry (high bush),
cranberry;
Mixing/loading/application by backpack to blueberry (high bush), cranberry;
Mixing/loading/application by mechanically pressurized handwand to cranberry;
Based on the number of applications and the timing of application, workers applying clethodim
would generally have a short (<30 days) duration of exposure.
Handler exposure was estimated based on the following personal protection:
Baseline PPE:
Long sleeved shirt, long pants and chemical-resistant gloves (unless
otherwise specified). For groundboom application, this scenario does not
include gloves as the data quality was better for non-gloved scenarios
than gloved scenarios.
Most dermal and inhalation exposures were estimated using data from the Pesticide Handlers
Exposure Database (PHED), Version 1.1. The PHED is a compilation of generic mixer/loader
applicator passive dosimetry data with associated software which facilitates the generation of
scenario-specific exposure estimates based on formulation type, application equipment, mix/load
systems and level of personal protective equipment (PPE).
Mixer/loader/applicator exposure estimates are based on the best available data at this time.
Route specific MOEs for mixer/loader and applicators for agricultural crops are outlined in
Appendix IV, Table 1. Calculated dermal, inhalation, and combined (total exposure from dermal
and inhalation routes) MOEs for mixer/loaders and applicators of clethodim exceeded target
MOEs for all uses and are not of concern.
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Postapplication Worker Exposure and Risk Assessment
The postapplication occupational risk assessment considered exposures to workers who enter
treated sites to conduct agronomic activities involving foliar contact (for example, scouting).
Based on the clethodim use pattern, there is potential for short-term (< 30 days) postapplication
exposure to clethodim residues for workers.
Activity specific transfer coefficients (TC) from the Agricultural Re-entry Task Force (ARTF)
were used to estimate postapplication exposure resulting from contact with treated turf and
foliage at various times after application. A TC is a factor that relates worker exposure to
dislodgeable residues. TCs are specific to a given crop and activity combination (for example,
hand harvesting apples, scouting late season corn) and reflect standard clothing worn by adult
workers. Postapplication exposure activities include (but are not limited to): scouting, weeding,
and transplanting.
Dislodgeable foliar residue (DFR) refers to the amount of residue that can be dislodged from the
leaves of plants. There were no chemical-specific dislodgeable foliar residue (DFR) studies
submitted to the PMRA for the re-evaluation of clethodim; therefore, the default peak value of
25% of the application rate with a dissipation rate of 10% per day was used for DFR
determination.
For workers entering a treated site, restricted entry intervals (REIs) are calculated to determine
the minimum length of time required before people can safely enter after application. An REI is
the duration of time that must elapse before residues decline to a level where performance of a
specific activity results in exposures above the target MOE.
The PMRA is concerned primarily with the potential for dermal exposure for workers
performing postapplication activities in crops treated with a foliar spray. Based on the vapour
pressure of clethodim, inhalation exposure is not likely to be of concern provided that the
minimum 12-hour REI is followed.
Calculated dermal MOEs for worker postapplication exposure to clethodim in agricultural crops
exceeded target MOEs and are not of concern. Current label REIs of 12 hours were maintained
for all postapplication activities. The postapplication exposure assessment is outlined in
Appendix IV, Table 2.
3.3
Dietary Exposure and Risk Assessment
In a dietary exposure assessment, the PMRA determines how much of a pesticide residue,
including residues in milk and meat, may be ingested with the daily diet. Exposure to clethodim
from potentially treated imports is also included in the assessment. These dietary assessments are
age specific and incorporate the different eating habits of the population at various stages of life.
For example, the assessments take into account differences in children’s eating patterns, such as
food preferences and the greater consumption of food relative to their body weight when
compared to adults.
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Dietary risk is then determined by comparing the exposure to the dietary reference doses that are
based on toxicity assessments. High toxicity may not indicate high risk if the exposure is low.
Similarly, there may be risk from a pesticide with low toxicity if the exposure is high.
The PMRA considers limiting use of a pesticide when risk exceeds 100% of the reference dose.
PMRA’s Science Policy Note SPN2003-03, Assessing Exposure from Pesticides – A User’s
Guide, presents detailed acute and chronic risk assessments procedures.
Residue estimates used in the dietary risk assessment (DRA) may be conservatively based on the
maximum residue limits (MRL) or the field trial data representing the residues that may remain
on food after treatment at the maximum label rate. Surveillance data representative of the
national food supply may also be used to derive a more accurate estimate of residues that may
remain on food when it is purchased. These include the Canadian Food Inspection Agency’s
National Chemical Residue Monitoring Program and the United States Department of
Agriculture Pesticide Data Program.
Acute and chronic dietary risk assessments were conducted using the Dietary Exposure
Evaluation Model - Food Commodity Intake Database™ (DEEM-FCID™; Version 3.16)
program, which incorporates food consumption data from the National Health and Nutrition
Examination Survey/“What We Eat in America” (NHANES/WWEIA) dietary survey for the
years 2003-2008. A cancer risk assessment was not required. For more information on dietary
risk estimates or residue chemistry information used in the dietary assessment, see Appendices
V, VI and VII.
3.3.1 Determination of Acute Reference Dose (ARfD)
To estimate acute dietary risk (1 day), the rat acute neurotoxicity study with a NOAEL of 100
mg/kg bw was selected for risk assessment. At the LOAEL of 1000 mg/kg bw, decreased
spontaneous activity, hunched posture, ruffled fur, head tilt and abnormal gait and salivation in
females were observed. These effects occurred within the first three days following a single oral
dose and are therefore relevant to an acute risk assessment. Standard uncertainty factors of 10fold for interspecies extrapolation and 10-fold for intra-species variability were applied. As
discussed in the Pest Control Products Act Hazard Characterization section, the Pest Control
Products Act factor was reduced to 1-fold. Thus, the composite assessment factor (CAF) is 100.
The ARfD is calculated according to the following formula:
ARfD = NOAEL = 100 mg/kg bw = 1.0 mg/kg bw
CAF
100
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3.3.2
Acute Dietary Exposure and Risk Assessment
The acute dietary risk was calculated considering the highest ingestion of clethodim that would
be likely on any one day, and using food consumption and food residue values. The expected
intake of residues is compared to the ARfD, which is the dose at which an individual could be
exposed on any given day and expect no adverse health effects. When the expected intake of
residues is less than the ARfD, then acute dietary exposure is not of concern.
Following the PMRA’s tiered approach, basic (screening level) risk assessments were performed
for all population subgroups by using MRL/tolerance-level residues for all commodities, default
processing factors and assuming that all crops were 100% treated. Canadian MRLs, US
tolerances or Codex MRLs, whichever was greater, were used for all crops, including imports.
Drinking water contribution to the exposure was accounted for by direct incorporation of the
appropriately estimated environmental concentration (EEC), obtained from water modelling (see
Section 3.4 below for details), into the dietary exposure evaluation model (DEEM-FCIDTM).
The acute aggregate exposure estimate for clethodim at the 95th percentile for the general
population is 3.6 % of the ARfD, and therefore is not of concern. The acute aggregate exposure
estimates for clethodim at the 95th percentile for all population subgroups range from 2.4% to
7.2% of the ARfD, and therefore are not of concern.
3.3.3 Determination of Acceptable Daily Intake (ADI)
To estimate chronic dietary risk for the general population, the chronic toxicity/oncogenicity
study in the rat was selected for risk assessment. A NOAEL of 16 mg/kg bw/day was
established, with decreases in body weight gain, increases in liver weight, and an increased
incidence of centrilobular hypertrophy, binucleated cells in the liver and chronic pancreatis at the
LOAEL of 86 mg/kg bw/day. Standard uncertainty factors (10-fold for interspecies extrapolation
and 10-fold for intraspecies variability) were applied. As previously discussed in the Pest
Control Products Act hazard characterisation section, the Pest Control Products Act factor has
been reduced to 1-fold. Thus, the composite assessment factor is 100.
ADI = 16 mg/kg bw/day = 0.16 mg/kg bw/day
100
The ADI provides a margin of safety of 625 to the NOAEL for fetal malformations in the rat
developmental toxicity study.
3.3.4
Chronic Dietary Exposure and Risk Assessment
The chronic dietary risk was calculated by using the average consumption of different foods and
the average residue values on those foods. This expected intake of residues was then compared to
the ADI. When the expected intake of residues is less than the ADI, then chronic dietary
exposure is not of concern.
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Following the PMRA’s tiered approach, basic (screening level) risk assessments were performed
for the general population and all population subgroups by using MRL/tolerance-level residues
for all commodities, default processing factors and assuming that all crops were 100% treated.
Canadian MRLs, US tolerances or Codex MRLs, whichever was greater, were used for all crops,
including imports. Drinking water contribution to the exposure was accounted for by direct
incorporation of the appropriately estimated environmental concentration (EEC), obtained from
water modelling (see Section 3.4 below for details), into the dietary exposure evaluation model
(DEEM-FCIDTM).
The chronic aggregate exposure estimate for clethodim for the general population is 8.7% of the
ADI, and therefore is not of concern. Exposure estimates for clethodim for population subgroups
range from 6.9% to 24.3% of the ADI, and therefore are not of concern.
3.3.5
Dietary Cancer Exposure and Risk Assessment
A cancer risk assessment was not required as no cancer concerns were identified.
3.4
Exposure from Drinking Water
Residues of clethodim in potential drinking water sources were estimated from modelling.
3.4.1
Concentrations in Drinking Water
Drinking water estimated environmental concentrations (EECs) of combined residues of
clethodim and its transformation products in potential drinking water sources (groundwater and
surface water) were generated using computer simulation models. EECs of clethodim in
groundwater were calculated using the PRZM-GW model to simulate leaching through a layered
soil profile over a 50-year period. The concentrations calculated using PRZM-GW are average
concentrations in the top 1m of the water table. EECs of clethodim in surface water were
calculated using the PRZM/EXAMS models, which simulate pesticide runoff from a treated field
into an adjacent water body, a small reservoir, and the fate of a pesticide within that water body.
A Level 1 drinking water assessment was conducted using conservative assumptions with respect
to environmental fate, application rate and timing, and geographic scenario. The model was run
for 50 years for all scenarios, and tested application dates between May and October. The highest
ground water EEC value of 0.041 ppm for combined residues of clethodim and its transformation
products was used in the acute and the chronic dietary risk assessments.
3.4.2
Drinking Water Exposure and Risk Assessment
Drinking water exposure estimates were not calculated separately. They were combined with
food exposure estimates, with EEC point estimates incorporated directly in the dietary (food +
drinking water) assessments. Please refer to Sections 3.3.2 and 3.3.4 for details and conclusions.
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3.5
Aggregate Exposure and Risk Assessment
Aggregate exposure is the total exposure to a single pesticide that may occur from food, drinking
water, residential, and other non-occupational sources, and from all known or plausible exposure
routes (oral, dermal and inhalation).
As clethodim is not registered for residential or non-occupational uses, the aggregate risk
assessment considered exposure from food and drinking water only. Aggregate risk from all
relevant sources is not of concern. Please refer to Sections 3.3.2 and 3.3.4 for details and
conclusions.
3.6
Cumulative Risk Assessment
The Pest Control Products Act requires that the PMRA consider the cumulative exposure to
pesticides with a common mechanism of toxicity. Although clethodim shares a common moiety
with sethoxydim, another herbicide currently registered in Canada, the toxicology review of
clethodim indicated that there is no common mechanism of toxicity between clethodim and
sethoxydim. Therefore, there is no requirement for a combined assessment of clethodim and
sethoxydim and/or their associated metabolites. 4.0
Impact on the Environment
4.1
Fate and Behaviour in the Environment
Clethodim is non-persistent under aerobic conditions in terrestrial systems. Biotransformation is
the major route of dissipation in the terrestrial environment. Clethodim transforms into three
major transformation products: clethodim sulfoxide, clethodim sulfone and clethodim oxazole
sulfone, all of which exhibit similar toxicity to that of the parent. Clethodim sulfoxide and
clethodim sulfone are slightly persistent, very highly mobile and are expected to reach ground
and surface water. Clethodim oxazole sulfone is formed late in the breakdown process of
clethodim and may persist in the environment. Based on low application rates and sequential
transformation of clethodim and its major transformation products in the environment, they are
not expected to accumulate and have significant carry over to the next growing season.
Clethodim, clethodim sulfoxide and clethodim sulfone are all very soluble in water. Although
clethodim ranges from low to very high mobility in soil (according to criteria from McCall et. al.
1981), because it is not persistent, it is not expected to leach to groundwater and is classified as a
non leacher (Gustafson, 1989). The transformation products clethodim sulfoxide and clethodim
sulfone are both very highly mobile in soil and are slightly persistent, giving them the potential
to leach to groundwater, according to the criteria of Cohen et al., 1984 and Gustafson, 1989.
In aerobic aquatic systems, clethodim is non-persistent to slightly persistent, while in anaerobic
aquatic systems, clethodim is persistent. In water, clethodim is rapidly transformed (half-life
ranges from < 3 minutes to 9.6 days) by photolysis and by microorganisms in aerobic and
anaerobic aquatic systems. Major transformation products include clethodim sulfoxide,
clethodim imine and clethodim imine sulfoxide. Clethodim sulfoxide and clethodim imine
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sulfoxide are moderately persistent while clethodim imine is persistent and could accumulate
over time. Clethodim and clethodim sulfoxide partition evenly between the water and sediment
layers, while clethodim imine and clethodim imine sulfoxide are expected to partition into
sediment where they may persist.
Clethodim is not expected to bioaccumulate in organisms.
The physical and chemical characteristics of clethodim are summarized in Appendix VIII, Table
1. The chemical structures and formation levels of transformation products can be found in
Appendix VIII, Table 2. The environmental fate data for clethodim and its transformation
products are summarized in Appendix VIII, Table 3.
4.2
Environmental Risk Characterization
The environmental risk assessment integrates the environmental exposure and ecotoxicology
information to estimate the potential for adverse effects on non-target species. This integration is
achieved by comparing exposure concentrations with concentrations at which adverse effects
occur. Estimated environmental exposure concentrations (EECs) are concentrations of pesticide
in various environmental media, such as food, water, soil and air. The EECs are estimated using
standard models which take into consideration the application rate(s), chemical properties and
environmental fate properties, including the dissipation of the pesticide between applications.
Ecotoxicology information includes acute and chronic toxicity data for various organisms or
groups of organisms from both terrestrial and aquatic habitats, including invertebrates,
vertebrates, and plants. Toxicity endpoints used in risk assessments may be adjusted to account
for potential differences in species sensitivity as well as varying protection goals (in other words,
protection at the community, population, or individual level).
Initially, a screening level risk assessment is performed to identify pesticides and/or specific uses
that do not pose a risk to non-target organisms, and to identify those groups of organisms for
which there may be a potential risk. The screening level risk assessment uses simple methods,
conservative exposure scenarios (for example, direct application at a maximum cumulative
application rate) and sensitive toxicity endpoints. A risk quotient (RQ) is calculated by dividing
the exposure estimate by an appropriate toxicity value (RQ = exposure/toxicity), and the risk
quotient is then compared to the level of concern (LOC). If the screening level risk quotient is
below the level of concern, the risk is considered negligible and no further risk characterization
is necessary. If the screening level risk quotient is equal to or greater than the level of concern,
then a refined risk assessment is performed to further characterize the risk. A refined assessment
takes into consideration more realistic exposure scenarios (such as drift to non-target habitats)
and might consider different toxicity endpoints. Refinements may include further
characterization of risk based on exposure modelling, monitoring data, results from field or
mesocosm studies, and probabilistic risk assessment methods.
Refinements to the risk assessment may continue until the risk is adequately characterized or no
further refinements are possible.
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4.2.1
Risks to Terrestrial Organisms
A risk assessment for clethodim was conducted for terrestrial organisms. For acute toxicity
studies, uncertainty factors of 1/2 and 1/10 are typically used to modify the toxicity values (EC50
and LC50) for terrestrial invertebrates, birds and mammals when calculating risk quotients (RQs).
No uncertainty factors are applied to chronic no observed effect concentration (NOEC)
endpoints. A summary of terrestrial toxicity data for clethodim is presented in Appendix VIII,
Table 4 and the accompanying risk assessment is presented in Appendix VIII, Table 5 for
beneficial arthropods, Appendix VIII, Table 6 for terrestrial organisms other than beneficial
arthropods, birds and mammals, Table 8 for further risk characterization to vascular plants and
Appendix VIII, Table 9 for birds and mammals.
Invertebrates
Earthworms
Screening level risk quotients for clethodim, the transformation product clethodim sulfoxide and
two end-use-products (EUPs) did not exceed the LOC on an acute basis for earthworms. The use
of clethodim is not expected to pose an unacceptable risk to earthworms.
Bees
Contact exposure: Risk to bees was calculated using results from an acute toxicity test with
clethodim and a separate test with a formulated EUP. The LOC was not exceeded (RQ <0.1).
Oral exposure: Toxicity endpoints from clethodim and a formulated EUP were used to determine
risk from an oral exposure to bees. The LOC was not exceeded (RQ <0.1).
The use of clethodim is not expected to pose an unacceptable risk on an acute oral or contact
basis to bees.
Larval bee toxicity: Exposure of bee larvae to the formulated end-use product is not expected
due to rapid dissipation of clethodim at the site of application. It is considered unlikely that bees
would transport end-use product material from food and pollen sources and carry it back to a
hive where long term exposure could result. In addition, lack of toxicity to adult bees and lack of
developmental effects on other invertebrates further confirm that clethodim would not pose
unacceptable risks to larval bees.
Arthropods
Extended lab studies conducted on sprayed plants and sprayed bean leaf discs indicated that the
survival and reproduction of the predatory mite, Typhlodromus pyri, was affected from exposure
to dry residues of formulated end-use product on bean leaf discs. In similar studies, the risk
quotient for the parasitic wasp, Aphidius rhopalosiphi, from acute and extended exposure on
sprayed plants did not exceed the LOC. A refined risk assessment for T. pyri was conducted,
looking at potential exposure from spray drift resulting from aerial and ground application.
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Risks to T. pyri were identified, in-field and off-field, following aerial and ground applications at
rates equal to and higher than the current registered lowest application rate of 45.6 g a.i./ha. The
use of clethodim may pose a risk to certain foliage-dwelling arthropods and, consequently, risk
reduction measures are required.
Birds and mammals
Birds
Birds showed no adverse effects to clethodim from either acute oral exposure or dietary intake.
Clethodim did not affect reproduction, mortality, behaviour, food consumption or body weight of
adult mallards during a 19-week exposure period. When bobwhite quails were exposed
chronically through food, there appeared to be a slight treatment-related reduction (21%) in the
percentage of viable embryos of egg sets at 833 mg a.i./kg diet (the highest concentration tested).
The NOEL was 188 mg ai/kg, equivalent to a daily exposure of 19.96 mg a.i./kg bw/d.
Mammals
Clethodim and the transformation product clethodim imine sulfone are practically non-toxic and
slightly toxic, respectively, to mammals on an acute basis. Adverse chronic effects (reduced
body weight of parent, reduced food consumption and reduced pup body weight) were seen in
rats in a two generation reproduction study with clethodim.
The EECs on food items (vegetation and insects) can be found in Table 7 of Appendix VIII.
For the bird and mammal risk assessment, the ingestion of food items contaminated by spray
droplets was considered to be the main route of exposure. The risk assessment was based on the
estimated daily exposure, which takes into account the expected concentration of clethodim on
various food items immediately after the last application and the amount of food consumed by
different sizes of birds and mammals. At the screening level, the most conservative exposure
estimates are used for each animal weight category.
The screening level risk assessment indicates that acute and chronic unacceptable risks are not
expected for birds and mammals exposed to clethodim (Appendix VIII, Table 8).
Terrestrial plants
Exposure of terrestrial vascular plants to clethodim end use product resulted in adverse effects on
seedling emergence and vegetative vigour of monocotyledonous plants.
As multiple EC50 values were available for vegetative vigour, the program ETX 2.0 was used to
generate a species sensitivity distribution (SSD) based on normally distributed toxicity data. The
hazardous concentration to 5% of the species (HC5) was then calculated from the SSD. The HC5
is the concentration that is theoretically protective for 95% of species. At the HC5 exposure level,
5% of all species will be exposed to a concentration which exceeds their LC50 toxicity value. The
HC5 values were used to calculate the risk quotients for terrestrial plants at the vegetative vigour
stage instead of the most sensitive species tested. This provides a more scientifically robust
endpoint, which uses all of the data. No uncertainty factors are applied to the HC5 when
calculating risk quotients. Using the HC5 value from the SSD for terrestrial plants, the calculated
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risk quotients exceeded the LOC at the screening level. A refined assessment looking at spray
drift was conducted and indicated that non-target plants within 1m of a treated field would be
exposed to clethodim concentrations exceeding the LOC for aerial (RQ = 8.8) and for ground
(RQ = 2.3) applications (Appendix VIII, Table 9). Consequently, mitigative measures, in the
form of spray buffer zones, are proposed to protect non-target terrestrial plants.
4.2.2 Risks to Aquatic Organisms
A risk assessment for clethodim was conducted for freshwater and marine aquatic organisms
based on available toxicity data. A summary of aquatic toxicity data is presented in Appendix
VIII, Table 10.
For acute toxicity studies, uncertainty factors of 1/2 and 1/10 are typically used to modify the
toxicity values (EC50 or LC50) for aquatic plants and invertebrates, and fish species, respectively,
when calculating risk quotients (RQs). No uncertainty factors are applied to chronic NOEC
endpoints. For groups where the LOC is exceeded (that is, RQ ≥1), a refined Tier 1 assessment is
conducted to determine risk resulting from spray drift and runoff separately. Risk quotients for
clethodim and its transformation products were calculated based on the highest maximum
seasonal application rate. The calculated risk quotients for clethodim and its transformation
products are summarized in Appendix VIII, Table 11 (screening level), Table 12 (Tier 1 – spray
drift only) and Table 13 (Tier 1 – runoff only).
Freshwater Invertebrates
The risk quotients for freshwater invertebrates, based on toxicity studies exposing Daphnia
magna to either clethodim, formulated EUP or the transformation product clethodim imine on an
acute basis, did not exceed the LOC at the screening level. The risk quotient for daphnids
resulting from chronic exposure to clethodim did exceed the LOC at the screening level. A
refined risk assessment, looking at chronic exposure of daphnids to clethodim spray drift, was
conducted, with risk quotients exceeding the LOC for aerial application (RQ = 3.1) only.
Clethodim may pose a chronic risk to freshwater invertebrates through spray drift from aerial
application and protective spray buffer zones are required.
Fish and amphibians
At the screening level, the acute exposure of freshwater fish to clethodim, formulated EUP or the
transformation product clethodim sulfoxide did not exceed the LOC. A chronic risk was
identified at the screening level for fathead minnow (RQ=1.14) and amphibians (RQ=6.1), based
on the early life stage study of fathead minnow. Refined risk assessments were conducted,
looking at drift and runoff. The LOC was not exceeded for the fathead minnow (RQ<1), but was
marginally exceeded for amphibians exposed to spray drift (RQ=1.4). As the LOC was exceeded
for the refined spray drift assessment, spray buffer zones are required to protect amphibians from
spray drift.
Algae
Clethodim, the formulated end-use product and the transformation product clethodim sulfoxide
are not expected to pose an unacceptable risk to algae as the risk quotients did not exceed the
LOC at the screening level.
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Freshwater vascular plants
The risk quotient for freshwater vascular plants, based on a toxicity study with Lemna gibba, did
not exceed the LOC at the screening level. The use of clethodim is not expected to pose an
unacceptable risk to freshwater vascular plants.
Marine organisms
The LOC was not exceeded for marine invertebrates, algae and fish in a screening level risk
assessment using clethodim and formulated end use product. The use of clethodim is not
expected to pose an unacceptable risk to marine organisms.
5.0
Value
Clethodim is a useful herbicide for Canadian producers due to its selectivity for annual and
perennial grasses along with its broadleaved crop tolerance. As a result, clethodim provides a
wide application window which only needs to consider the height and growth stage of the
targeted weeds because many broadleaved crops are tolerant to clethodim at all stage of growth.
Clethodim can also be tank-mixed with many broadleaf herbicides to broaden the spectrum of
weed control.
Clethodim is one of the broadest spectrum grass herbicides available to Canadian growers. It is
one of few grass herbicides providing effective control of perennial grassy weeds. It is widely
used to control grass weeds in many important crops grown in Canada such as canola, pulses and
other oilseed crops. It is the only herbicide registered for use on prairie carnation. It is one of few
herbicides registered for use on minor crops and often the only alternative grass herbicide to
sethoxydim for use on minor crops.
Many minor uses of clethodim were registered through the User Requested Minor Use Label
Expansion (URMULE) program and were identified at the time as priorities for crop production
in Canada. In addition, clethodim is identified as a priority in the Canadian Grower Priority
Database for a variety of crops.
Clethodim is a WSSA Group 1 mode of action herbicide (ACCase inhibitor). In Canada,
populations of several key grassy weed species have developed resistance to this mode of action.
Wild oats, green foxtail, large crabgrass and Persian darnel are examples of such resistant weeds
reported in Canada. These ACCase inhibitor-resistant weeds affect the efficacy and broader
value of clethodim. In order to prevent or delay the development of ACCase inhibitor-resistant
weeds, it is crucial to maintain diversity in weed management practices.
Proposed Re-evaluation Decision - PRVD2016-11
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6.0
Pest Control Product Policy Considerations
6.1
Toxic Substances Management Policy Considerations
The Toxic Substances Management Policy (TSMP) is a federal government policy developed to
provide direction on the management of substances of concern that are released into the
environment. The TSMP calls for the virtual elimination of Track 1 substances (those that meet
all four criteria outlined in the policy, in other words, persistent in air, soil, water and/or
sediment, bioaccumulative, primarily a result of human activity and toxic as defined by the
Canadian Environmental Protection Act).
During the review process, clethodim and its transformation products were assessed in
accordance with the PMRA Regulatory Directive DIR99-033 and evaluated against the Track 1
criteria. The PMRA has reached the following conclusions:
6.2

Clethodim does not meet all Track 1 criteria, and is not considered a Track 1 substance.

Clethodim does not form any transformation products that meet all Track 1 criteria.
Formulants and Contaminants of Health or Environmental Concern
During the review process, contaminants in the technical and formulants and contaminants in the
end-use products are compared against the List of Pest control Product Formulants and
Contaminants of Health or Environmental Concern maintained in the Canada Gazette4. The list
is used as described in the PMRA Notice of Intent NOI2005-015 and is based on existing policies
and regulations including DIR99-03 and DIR2006-026, and taking into consideration the Ozonedepleting Substance Regulations, 1998, of the Canadian Environmental Protection Act
(substances designated under the Montreal Protocol). The PMRA has reached the following
conclusions:
Technical grade clethodim does not contain any formulants or contaminants of health or
environmental concern identified in the Canada Gazette. However, clethodim end-useproducts contain an aromatic petroleum distillate, and therefore, a corresponding advisory
statement is proposed to be added to product labels.
3
DIR99-03, The Pest Management Regulatory Agency’s Strategy for Implementing the Toxic Substances
Management Policy.
4
Canada Gazette, Part II, Volume 139, Number 24, SI/2005-114 (2005-11-30) pages 2641–2643: List of
Pest Control Product Formulants and Contaminants of Health or Environmental Concern and in the order
amending this list in the Canada Gazette, Part II, Volume 142, Number 13, SI/2008-67 (2008-06-25) pages
1611-1613. Part 1 Formulants of Health or Environmental Concern, Part 2 Formulants of Health or
Environmental Concern that are Allergens Known to Cause Anaphylactic-Type Reactions and Part 3
Contaminants of Health or Environmental Concern.
5
NOI2005-01, List of Pest Control Product Formulants and Contaminants of Health or Environmental
Concern under the New Pest Control Products Act.
6
DIR2006-02, Formulants Policy and Implementation Guidance Document.
Proposed Re-evaluation Decision - PRVD2016-11
Page 24
The use of formulants in registered pest control products is assessed on an ongoing basis through
PMRA formulant initiatives and Regulatory Directive DIR2006-02.
7.0
Incident Reports
Since 26 April 2007, registrants have been required by law to report incidents to the PMRA that
include adverse effects to Canadian health or the environment. Information about the reporting of
pesticide incidents can be found on the Pesticides and Pest Management portion of Health
Canada’s website. Incident reports involving the active ingredient clethodim were reviewed. As
of 24 November 2014, no environmental incidents involving clethodim had been reported to the
PMRA or the United States Environmental Protection Agency.
As of 17 March 2015, the PMRA had received reports of three human incidents involving
clethodim. The effects in the three human incidents were considered to be at least probably
associated with the reported exposure to the pest control products involved in the incidents.
However, in two of the incidents, additional products were involved and as such, the role of
clethodim in particular cannot be isolated. The three incidents involved dermal effects which
occurred after the product splashed onto exposed skin or clothing.
These incident reports were considered in this evaluation. Overall, the findings do not impact the
risk assessment as the hazard labelling already accounts for the dermal irritation properties of
clethodim.
8.0
Organisation for Economic Co-operation and Development Status of
Clethodim
Canada is part of the Organisation for Economic Co-operation and Development (OECD), which
groups member countries and provides a forum in which governments can work together to share
experiences and seek solutions to common problems.
As part of the re-evaluation of an active ingredient, the PMRA takes into consideration recent
developments and new information on the status of an active ingredient in other jurisdictions,
including OECD member countries. In particular, decisions by an OECD member to prohibit all
uses of an active ingredient for health or environmental reasons are considered for relevance to
the Canadian situation.
Clethodim is currently acceptable for use in other OECD countries, including the United States,
Australia and the European Union. As of 23 April 2015, no decision by an OECD member
country to prohibit all uses of clethodim for health or environmental reasons has been identified.
Proposed Re-evaluation Decision - PRVD2016-11
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9.0
Proposed Re-evaluation Decision
After a re-evaluation of the herbicide clethodim, Health Canada’s PMRA, under the authority of
the Pest Control Products Act and Regulations, is proposing continued registration of clethodim
and associated end-use products, provided that the risk-reduction measures described in this
document are implemented.
The proposed regulatory actions for clethodim are summarized in the following sections. The
labels of Canadian end-use products are proposed to be amended to include the risk-reduction
measures listed in Appendix IX.
9.1
Proposed Regulatory Actions
9.1.1
Proposed Regulatory Action Related to Human Health
As a result of the exposure assessment, the following clarifications are proposed to further
protect human health and minimize unnecessary exposure:



Additional label statements to clarify the protective equipment for workers applying
clethodim.
Clarification that clethodim is not registered for use in greenhouses.
A statement to promote best management practices to minimize human exposure from
spray drift or spray residues resulting from drift.
In addition, clethodim is registered for use on various crops. The residue definition (RD) in all
crops and animal commodities comprises the parent clethodim and metabolites containing the 2cyclohex-1-enone moiety. This RD is used for both enforcement and dietary risk assessment
purposes. No modification to the current RDs is proposed as the result of this re-evaluation.
However, it is suggested that the RD be worded as “sum of clethodim and its metabolites
containing the 2-cyclohex-1-enone moiety, expressed as clethodim”. The RD in drinking water
for dietary risk assessment is defined as the sum of clethodim and its transformation products in
water sources. See Table 2 of Appendix VII for the current and proposed Canadian RD wording,
as well as the RDs of other jurisdictions.
9.1.2
Proposed Regulatory Action Related to the Environment
Clethodim, its end-use products and its major transformation products are not expected to pose
an unacceptable risk to earthworms, bees, birds, small mammals, freshwater algae, aquatic plants
and marine orgnisms. Clethodim may pose a risk to certain beneficial arthropods, non-target
terrestrial plants, freshwater invertebrates and amphibians. In order to minimize potential
exposure to clethodim in terrestrial and aquatic habitats, precautionary statements and spray
buffer zones (Appendix IX) are proposed.
Proposed Re-evaluation Decision - PRVD2016-11
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10.0 Supporting Documentation
PMRA documents, such as Regulatory Directive DIR2012-02, Re-evaluation Program Cyclical
Re-evaluation, and DACO tables can be found on the Pesticides and Pest Management portion of
Health Canada’s website. PMRA documents are also available through the Pest Management
Information Service. Phone: 1-800-267-6315 within Canada or 1-613-736-3799 outside Canada
(long distance charges apply); fax: 613-736-3798; e-mail: pmra.infoserv@hc-sc.gc.ca
The federal TSMP is available through Environment Canada’s website.
Proposed Re-evaluation Decision - PRVD2016-11
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Proposed Re-evaluation Decision - PRVD2016-11
Page 28
List of Abbreviations
List of Abbreviations
µg
ADI
AFC
a.i.
ALP
ARfD
BAF
BCF
bw
bwg
Bz
CAF
CAS
CFIA
cm
cm2/h
CMC
D
DACO
DER
DFR
DHR
DT50
EC50
EDE
EEC
EFSA
et al.
EUP
F1
F2
fc
FIR
g
GAP
GD
ha
HAFT
Hct
Hgb
IRAC
IUPAC
kg
Kd
microgram
acceptable daily intake
antibody forming cell
active ingredient
alkaline phosphatase
acute reference dose
bioaccumulation factor
bioconcentration factor
body weight
body weight gain
benzyl ring label
composite assessment factor
chemical abstracts service
Canadian Food Inspection Agency
centimetres
centimetres squared per hour
carboxymethylcellulose
day
data code
data evaluation record
dislodgeable foliar residue
3
H-dihydrorotenone
dissipation time 50% (the time required to observe a 50% decline in
concentration)
effective concentration on 50% of the population
estimated daily exposure
estimated environmental concentration
European Food Safety Authority
and others
end-use products
first filial generation
second filial generation
Food consumption
food ingestion rate
gram
Good Agricultural Practice
gestation day
hectare(s)
highest average field trial
hematocrit
hemoglobin
Insecticide Resistance Action Committee
International Union of Pure and Applied Chemistry
kilogram
soil-water partition coefficient
Proposed Re-evaluation Decision - PRVD2016-11
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List of Abbreviations
KF
Koc
Kow
L
LC50
LD50
LOAEL
LOC
LOEC
LOQ
LPM
LR50
MAS
mg
MIS
mL
MOE
mPa
MP HG
MP HW
MRL
MTDB
N/A
NOAEL
NOAEC
NOEC
NOEL
OECD
P
PCP
PD
PHED
PHI
PMRA
PND
PPE
ppm
PVA
Pz
RBC
REI
RLD
RQ
SHD
SLD
SNpc
TC
Freundlich adsorption coefficient
organic-carbon partition coefficient
octanol-water partition coefficient
litre
lethal concentration 50%
lethal dose 50%
lowest observed adverse effect level
level of concern
lowest observed effect concentration
limit of quantitation
litres per minute
lethal rate 50%
maximum average score
milligram
mean irritation score
millilitre
margin of exposure
millipascal
mechanically pressurized hand-held sprayer
manually pressurized hand-held sprayer
maximum residue limit
maximum theoretical dietary burden
not applicable
no observed adverse effect level
no observed adverse effect concentration
no observed effect concentration
no observed effect level
Organisation for Economic Co-operation and Development
parental generation
pest control product
Parkinson’s disease
Pesticide Handlers Exposure Database
pre-harvest Interval
Pest Management Regulatory Agency
postnatal day
personal protective equipment
parts per million
polyvinyl alcohol
pyridazinone ring label
red blood cells
restricted entry interval
repeat low dose
risk quotient
single high dose
single low dose
substantia nigra pars compacta
transfer coefficient
Proposed Re-evaluation Decision - PRVD2016-11
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List of Abbreviations
TGAI
TRR
TSMP
URMULE
USC
USEPA
UV
WSP
♂
♀
↑
↓
%CT
technical grade active ingredient
total radioactive residue
Toxic Substances Management Policy
User Requested Minor Use Label Expansion
use site category
United States Environmental Protection Agency
ultraviolet
wettable powder in water soluble packaging
males
females
increased
decreased
percent crop treated
Proposed Re-evaluation Decision - PRVD2016-11
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List of Abbreviations
Proposed Re-evaluation Decision - PRVD2016-11
Page 32
Appendix I
Appendix I Clethodim Products Registered in Canada as of 29 January 20141
Registration
Number
Marketing
Class
Registrant
Product Name
Commercial
Arysta
Lifescience
North America,
LLC
Select Emulsifiable
Concentrate Post-Emergence
Herbicide
26426
Commercial
Bayer
Compas Grass Herbicide
Cropscience Inc.
27598
Commercial
28224
Commercial
29277
Commercial
22624
Manufacturing
Concentrate
28226
Manufacturing
Concentrate
28698
Manufacturing
Concentrate
22625
Centurion Emulsifiable
Bayer
Concentrate Post-Emergence
Cropscience Inc.
Herbicide
Makhteshim
Agan of North
Arrow 240 EC
America Inc.
Loveland
Shadow RTM Emulsifiable
Products Canada Concentrate Post-Emergence
Inc.
Herbicide
Arysta
Lifescience
Clethodim 37%
North America, Manufacturing Use Product
LLC
Makhteshim
Agan Of North
Clethodim 37% MUP
America Inc
Makhteshim
Arrow Manufacturing Use
Agan Of North
Product
America Inc
Formulation
Type
Guarantee
Emulsifiable
Concentrate Or
Emulsion
240 g ai/L
Emulsifiable
Concentrate Or
Emulsion
Emulsifiable
Concentrate Or
Emulsion
Emulsifiable
Concentrate Or
Emulsion
Emulsifiable
Concentrate Or
Emulsion
240 g ai/L
240 g ai/L
240 g ai/L
240 g ai/L
Solution
37%
Solution
37%
Emulsifiable
Concentrate Or
Emulsion
Proposed Re-evaluation Decision - PRVD2016-11
Page 33
240 g ai/L
Appendix I
1
Registration
Number
Marketing
Class
22623
Technical
Grade Active
Ingredient
28211
Technical
Grade Active
Ingredient
Registrant
Arysta
Lifescience
North America,
LLC
Makhteshim
Agan of North
America Inc.
Formulation
Type
Product Name
Clethodim Technical
Liquid
Clethodim Technical
Herbicide
Solution
excluding discontinued products or products with a submission for discontinuation
Proposed Re-evaluation Decision - PRVD2016-11
Page 34
Guarantee
95%
93.3%
Appendix II
Appendix II
USCs1
Clethodim Uses Registered in Canada as of 29 January 2014.
Site(s)2
Weeds
Canola
Grass weeds including foxtail
(green, yellow), Persian darnel, wild
oats, volunteer cereals (wheat,
barley, oats), barnyard grass,
witchgrass, fall panicum, proso
millet, volunteer corn, volunteer
canary grass, quackgrass
Ground and aerial
91.2
91.2
Canola,
imzethapyr
tolerant
Tank mix with Pursuit for control of
certain broadleaf and grassy weeds
Ground
45.6
45.6
1
15.12
15.12
1
91.2
91.2
91.2
91.2
Canola,
glufosinate
tolerant
7
13
14
Geographic
area
restrictions is
specified in
the
Application
Equipment
column
Flax
(including
low linolenic
acid varieties)
Mustard,
yellow
13
14
Maximum Application
Rate (g ai/ha)
Application
Method and
Equipment
Mustard,
oriental
(brown) oilseed types
Mustard,
oriental
(brown) condiment
Single3
Cumulative
Per Year3
Maximum Number of Application Per Year
Typically only one application is made per season.
However, 2 applications at 45 g a.i./ha at a minimum 14day interval may be used
Ground and aerial
Prairie provinces
and Peace River
region of BC only
Tank mix with Liberty 150 SN for
control of certain broadleaf and
grassy weeds
Ground
Eastern Canada
and BC only
Grass weeds including foxtail
(green, yellow), Persian darnel, wild
oats, volunteer cereals (wheat,
barley, oats), barnyard grass,
witchgrass, fall panicum, proso
millet, volunteer corn, volunteer
canary grass, quackgrass
Typically only one application is made per season.
However, 2 applications at 45 g a.i./ha at a minimum 14day interval may be used
Ground and aerial
91.2
91.2
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Appendix II
USCs1
7
13
14
Site(s)2
Application
Method and
Equipment
Weeds
Maximum Application
Rate (g ai/ha)
Single3
Cumulative
Per Year3
Lentils
91.2
91.2
Potatoes
91.2
91.2
Soybeans
91.2
91.2
45.6
45.6
Soybeans,
glyphosate
tolerant
Volunteer glyphosate tolerant corn
and other weeds
Ground
Maximum Number of Application Per Year
13
14
Peas, field
91.2
91.2
7
13
14
Sunflowers
91.2
91.2
45.6
45.6
45.6
45.6
91.2
91.2
[1]
91.2
91.2
1
13
14
13
14
Dry common
beans
(phaseolus
vulgaris
varieties only
such as pinto,
black, great
northern, red,
pink and
navy)
Desi and
Kabuli
chickpeas
13
Alfalfa,
seedling
14
Blueberry,
highbush
(Minor use)
Typically only one application is made per season.
However, 2 applications at 45 g a.i./ha at a minimum 14day interval may be used
Ground and aerial
Grass weeds including foxtail
(green, yellow), Persian darnel, wild
oats, volunteer cereals (wheat,
barley, oats), barnyard grass,
witchgrass, fall panicum, proso
millet, volunteer corn, volunteer
canary grass, quackgrass
Ground
1
1
Ground
Application as a
broadcast spray
directed to the
ground
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Page 36
Appendix II
1.
2.
3.
USCs1
Site(s)2
14
Coriander
(Minor use)
14
Fenugreek
(Minor use)
13
14
Dry onions
(Minor use)
7
14
Prairie
carnation –
Alberta,
Saskatchewan
and Manitoba
only
(Minor use)
14
Spinach
(Minor use)
7
14
Safflower
(Minor use)
14
Cranberry
(Minor use)
Application
Method and
Equipment
Weeds
Grass weeds including foxtail
(green, yellow), Persian darnel, wild
oats, volunteer cereals (wheat,
barley, oats), barnyard grass,
witchgrass, fall panicum, proso
millet, volunteer corn, volunteer
canary grass, quackgrass and annual
bluegrass (suppression)
Grass weeds including foxtail
(green, yellow), Persian darnel, wild
oats, volunteer cereals (wheat,
barley, oats), barnyard grass,
witchgrass, fall panicum, proso
millet, volunteer corn, volunteer
canary grass, quackgrass
Maximum Application
Rate (g ai/ha)
Maximum Number of Application Per Year
Single3
Cumulative
Per Year3
Ground
91.2
91.2
1
Ground
91.2
91.2
1
Ground
91.2
91.2
1
Ground
45.6
45.6
1
Ground
45.6
91.2
2
Ground
91.2
91.2
1
Ground
91.2
91.2
1
USCs 1 to 14 belong to the use sector AGRICULTURE AND FORESTRY.
Sites are as either stated on the label or interpreted by PMRA so as to achieve consistency in naming.
Rates of active ingredient (a.i.) were calculated by the PMRA. Note that the cumulative a.i. rate per year specified on the labels is 90 g a.i./ha when the cumulative product rate per year is 0.38
L/ha.
Proposed Re-evaluation Decision - PRVD2016-11
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Appendix II
Proposed Re-evaluation Decision - PRVD2016-11
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Appendix III
Appendix III
Toxicology Endpoints for Health Risk Assessments
Table 1 Toxicity profile of clethodim
Effects are known or assumed to occur in both sexes unless otherwise noted; in such cases, sexspecific effects are separated by semi-colons. Organ weight effects reflect both absolute organ
weights and relative organ to bodyweights unless otherwise noted. Effects seen above the
LOAEL(s) have not been reported in this table for most studies for reasons of brevity.
Study Type/Animal/PMRA #
Toxicokinetics
Absorption, Distribution,
Metabolism and Excretion Sprague-Dawley rats
gavage
PMRA #1227015, 1232651
Study Results
After 7 days the total amount of radiolabel recovered from organs and
tissues in each of the dose groups, low, high and repeat dose, was less than
1% of the administered dose. The concentration in the tissues was adrenals
> liver > kidney > bone, spinal cord, followed by the remaining tissues.
Excretion of the 14C-label was rapid and complete in the urine (87.293.2%), feces (9.3-17.0%) and carbon dioxide (0.5-1.0%); most (93.598.2%) was eliminated within 48 h.
The major metabolite of 14C clethodim was clethodim sulfoxide; in
addition, smaller amounts of clethodim, clethodim sulfone, imine sulfoxide
and 5-OH sulfone were present in the tissues.
A metabolic pathway was suggested in which clethodim is rapidly oxidized
to clethodim sulfoxide. Clethodim sulfoxide can be further oxidized to
clethodim sulfone, deoxyalkylated to the imine sulfoxide or hydroxylated
at the 5-position of the ring to yield 5-OH sulfoxide or 5-OH sulfone.
Acute oral toxicity
LD50 (♂) = 2570 mg/kg bw
gavage
LD50 (♀) = 2430 mg/kg bw
CD1 mice
Signs: hypoactivity, rough coat, hunched posture, ataxia, urine stains,
tremors, salivation
PMRA #1229860, 1229861
Necropsy: in mice that died: slightly dark-red lungs, compound like
material in the GI tract (no abnormalities noted in surviving mice)
low toxicity
Acute oral toxicity
LD50 (♂) = 1630 mg/kg bw
gavage
LD50 (♀) = 1360 mg/kg bw
Sprague-Dawley rats
Signs: Day 1: salivation, ↓motor activity, clonic convulsions, tremoring
and/or unsteady gait, hyperactivity, collapse. Day 2-6 in survivors: ↓food
consumption, yellow anogenital staining.
PMRA #1229862, 1232654
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Appendix III
Study Type/Animal/PMRA #
Study Results
Necropsy: dark gelatinous material beneath the meninges,
mottled/reddened lungs, foam in the trachea, very small lesions of gliosis
in a single spinal nerve in lower lumbar area in 2 ♀s at 1.45 g/kg bw.
slightly toxic
Acute dermal toxicity
LD50 > 5000 mg/kg bw
New Zealand White rabbits
Signs: dermal effects included abraded, thickened, blackened/darkened,
crusty and/or cracked skin. One male showed reduced food intake,
decreased motor activity, decreased body temperature, unkempt
appearance, diarrhea, no feces and collapse before dying on day 6.
PMRA #1229863, 1232667
low toxicity
Acute inhalation toxicity
LC50 >3.9 mg/L
Sprague-Dawley rats
Signs: salivation, red nasal discharge, abnormal respiratory sounds,
mydriasis, decreased feces, unkempt appearance, yellow/red anogenital
discharge
PMRA #1229864, 1232669
low toxicity
Eye irritation
MIS: 11.7 (1h unwashed); 10.7 (1h washed)
MAS: 3.0 (unwashed); 0.43 (washed)
New Zealand White rabbits
All eyes were clear of irritation at 72h in the unwashed eyes, 48h in the
washed
PMRA #1229865, 1232670
mild eye irritant
Dermal irritation
MIS(intact): (Trial 1) 1.75 (72h); (Trial 2) 0.25 (48h)
MAS(intact): (Trial 1) 1.17; (Trial 2) 0.17
New Zealand White rabbits
PMRA #1229866, 1232671
mild dermal irritant
Dermal sensitization (modified non-sensitizer
Buehler)
Hartley Guinea pig
PMRA #1229868, 1232673
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Appendix III
Study Type/Animal/PMRA #
4-week dermal toxicity study
Study Results
Systemic
NOAEL = 100 mg/kg bw/day
Sprague-Dawley rats
LOAEL = 1000 mg/kg bw/day based on ↑urogenital discharge; ↓bw gain
(♂: -35.2%), ↓bw (♂: -6.9%); ↑liver wt.(♀)
PMRA #1227481
Dermal
NOAEL not determined.
LOAEL = 10 mg/kg bw/day based on skin irritation
There was a dose-related skin irritation in treated animals
4-week feeding study
CD-1 mice
NOAEL = 111 mg/kg bw/day (625 ppm)
LOAEL = 274 mg/kg bw/day (1500 ppm) based on ↓RBC (♂;♀-this dose
only), ↓Hgb (♂;♀-this dose only); ↑liver wt.(♂)
No analysis of serum chemistry was performed.
PMRA #1229869, 1231831,
1231977
5-week feeding study
Sprague-Dawley rats
NOAEL = 65.6/70.6 mg/kg bw/day (1000 ppm)
LOAEL = 261/291 mg/kg bw/day (4000 ppm) based on ↓food
consumption (wk 1 only), ↓bw, ↓bw gain, ↑liver wt., centrilobular
hypertrophy (trace to mild); ↓Hct (♂); ↑uric acid (♀)
PMRA #1229870-1
13-week feeding study
NOAEL (♂) = 25 mg/kg bw/day (500 ppm)
NOAEL (♀) = 159 mg/kg bw/day (2500 ppm)
Sprague-Dawley rats
LOAEL (♂) = 134/159 mg/kg bw/day (2500 ppm) based on ↑liver wt,
centrilobular hypertrophy of liver, ↑incidence of focal regeneration of the
kidney; ↓bw (♂)
PMRA #1229872-4, 1229882,
LOAEL (♀) = 279/341 mg/kg bw/day (5000 ppm) based on ↓food
1232674
consumption , ↑organ wt. (rel. - brain, kidney); ↑cholesterol (♂), ↑total
protein (♂), ↑globulin (♂); ↓bw (♀)
In animals recovering for 6 weeks, bwg was greater than controls but bw
remained less than control wt. Organ wts. following recovery were
generally similar to controls. No focal regeneration in the kidney, or liver
hypertrophy was present in the recovery groups.
3-month feeding study
NOAEL = 62.5 mg/kg bw/day
LOAEL = 104 mg/kg bw/day based on ↑liver wt. (absol.), ↑severity of
cytoplasmic vesiculation/vacuolation of the central lobular hepatocytes;
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Appendix III
Study Type/Animal/PMRA #
Study Results
Beagle dogs
↑globulin (♂), ↓albumin/globulin (♂); ↑ALP (♀)
PMRA #1229893, 1231833
1-year feeding study
NOAEL = 0.8 mg/kg bw/day*
LOAEL = 62.5 mg/kg bw/day based on ↑liver wt., hypercellularity of the
bone marrow (1/6 ♂; 1/6 ♀); ↑polynuclear neutrophils (♀), ↑platelets (♀),
↓glucose (♀), ↑spleen pigment (♀),
Beagle dogs
*based on the 90-day dog study the NOAEL could be set at 20.8 mg/kg
bw/day. There were minor effects at 62.5 mg/kg bw/day in both studies
and a large gap to the next lower dose in the 1-year study suggesting a
NOAEL for the 1-year study of 20.8 mg/kg bw/day (in other words, the
next lower dose in the 90-day study) would be appropriate.
PMRA #1229901
18-month feeding study
NOAEL = 19.5/25.3 mg/kg bw/day (200 ppm)
CD - 1 mice
LOAEL ≥106/143 mg/kg bw/day (1000 ppm) based on ↓survival,
↑multifocal, amphophilic alveolar lung macrophages, ↑centrilobular
hypertrophy, ↑pigment in liver, ↑bile duct hyperplasia; ↑liver weight (♂liver/body wt. and liver/brain wt. at wk. 53),
PMRA #1226180, 1226185,
1226186, 1226187, 1226188,
1226982, 1231837, 1234279
not carcinogenic
2-year feeding study
NOAEL = 16 mg/kg bw/day (500 ppm)
LOAEL = 86/113 mg/kg bw/day (2500 ppm) based on ↓bw, ↑liver
weight, ↑incidence of chronic pancreatitis, slight ↑incidence of binucleated
cells of the liver.
Sprague-Dawley rats
PMRA #1227371-7, 1227379,
1227381, 1227451, 1227453-9,
1230580, 1230582-5
Dietary 2-generation
reproductive study
Sprague-Dawley rats
PMRA #1227382, 1227383,
1227384, 1227385,1227386,
1227387, 1227388, 1227389,
1227390, 1227391, 1227399,
1234281
No treatment-related increase in tumours
not carcinogenic
Parental
NOAEL = 28 mg/kg bw/day (500 ppm)
LOAEL = 148 mg/kg bw/day (2500 ppm) based on ↓bw (♂- F0 & F1, ♀ F1), ↓fc (occasional)
Offspring
NOAEL ≥148 mg/kg bw/day (2500 ppm)
LOAEL not established
148 mg/kg bw/day (2500 ppm): ↓pup bw [F1a→F2a generation, slight
during lactation ](not statistically significant and considered non-adverse)
Proposed Re-evaluation Decision - PRVD2016-11
Page 42
Appendix III
Study Type/Animal/PMRA #
Study Results
Reproductive
NOAEL ≥148 mg/kg bw/day (2500 ppm)
LOAEL not established
No treatment-related effects were observed.
Developmental toxicity study
Maternal
gavage
NOAEL = 100 mg/kg bw/day
LOAEL = 350 mg/kg bw/day based on clinical signs (↑incidence of
excessive salivation, red nasal discharge, staining of fur in the ano-genital
region), ↓bw, ↓uterine wt.
CD rats
PMRA #1228811, 1228823,
1231978, 1231979, 1234282
Developmental
NOAEL = 100 mg/kg bw/day
LOAEL = 350 mg/kg bw/day based on ↓fetal bw, ↑skeletal variations
(delayed ossification)
Malformations at doses exceeding MTD
Developmental toxicity study
Maternal
gavage
NOAEL = 83 mg/kg bw/day
LOAEL = 249 mg/kg bw/day based on ↓bw, ↓bwg, ↓fc and feed
utilization (days 7-20), ↑incidence dried feces and red substance in pan
(thought to be due to GI irritation rather than abortion)
New Zealand White rabbits
PMRA #1228837, 1228848,
1228859
Developmental
NOAEL ≥249 mg/kg bw/day
LOAEL not established
249 mg/kg bw/day: slight ↑skeletal variations (non-adverse)
negative
Ames test
S. typhimurium TA98, TA100,
TA1535, TA1537, E. coli WP2
uvrA
PMRA #1226179, 1232645
Ames test
negative
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Page 43
Appendix III
Study Type/Animal/PMRA #
Study Results
S. typhimurium TA98, TA100,
TA1535, TA1537
PMRA #1226181, 1232646
Chromosome aberrations in
CHO cells
positive w/o activation only
Positive when tested in the absence of metabolic activation. A significant
Chinese Hamster Ovary (CHO) increase in the frequency of structural chromosome aberrations per cell
was observed at 1.0 and 1.2 μL/mL. No significant increase was seen in
Cells
either structural aberrations per cell in the activated system or in numerical
aberrations for either test system.
PMRA #1226182, 1232647
Chromosome aberrations in
CHO cells
negative
Negative with and without metabolic activation ≤1.2 μL/mL
Chinese Hamster Ovary (CHO)
This is a repeat of the above using a much purer form of the technical. An
Cells
impurity seems likely responsible for the positive effect noted above.
PMRA #2456233
In vivo chromosome aberration
assay
negative
Sprague-Dawley rat bone
marrow
PMRA #1226183, 1232643
Unscheduled DNA Synthesis
negative
hepatocytes of B6C3F1 mice
PMRA #1226184, 1232648
Acute oral neurotoxicity study NOAEL = 100 mg/kg bw
Wistar rats
LOAEL = 1000 mg/kg bw based on ↓bwg, ↓spontaneous activity,
hunched posture, ruffled fur, ↑nerve fibre degeneration of the ventral
lumbar root; abnormal gait (♀), 8salivation (♀), head tilt (♀)
PMRA #1371485, 1371486
Proposed Re-evaluation Decision - PRVD2016-11
Page 44
Appendix III
Study Type/Animal/PMRA #
28-day oral (dietary) rangefinding neurotoxicity study
Sprague-Dawley rats
Study Results
≥45/51 mg/kg bw/day (500 ppm): ↓bwg; ↓bw (♂)
≥132/155 mg/kg bw/day (1500 ppm): ↑liver weight (♀)
No neurotoxic potential was indicated up to the highest dose-levels tested
(441/475 mg/kg bw/day). This study was used to establish the doses in the main
90-day neurotoxicity study
PMRA #2308446
90-day oral (dietary)
neurotoxicity study
NOAEL = 94/115 mg/kg bw/day
LOAEL = 331/380 mg/kg bw/day (5000 ppm) based on ↓bw, ↑liver
weight
Sprague-Dawley rats
PMRA #2308444
28-day oral (dietary) range≥551 mg/kg bw/day (2000 ppm): ↑liver weight
finding immunotoxicity study.
B6C3F1 mice
PMRA #2308448
28-day oral (dietary)
immunotoxicity study.
B6C3F1 mice
PMRA #2308450
Plant Metabolites:
Imine sulfone (RE-47719)
acute oral toxicity
gavage
NOAEL = 136 mg/kg bw/day
LOAEL = 603 mg/kg bw/day (2000 ppm) based on ↑liver weight, slight
↓spleen weight, slight ↓spleen cells, slight ↓specific activity AFC’s, slight
↓total spleen activity AFC’s
Equivocal evidence for immunotoxicity
LD50 (♀) > 1400 mg/kg bw
One animal had ↓motor activity 4 hours after dosing and was found dead
the following morning. All other animals appeared normal.
Sprague-Dawley rats
Necropsy: small intestine of animal that died contained red gelatinous
material.
PMRA #1227466
The results suggest that imine sulphone is less acutely toxic than clethodim
to the ♀ rat.
Plant Metabolites:
1) 5-OH sulfone: 1400 mg/kg bw: no mortality, or clinical signs of
Proposed Re-evaluation Decision - PRVD2016-11
Page 45
Appendix III
Study Type/Animal/PMRA #
5-OH sulfone (RE-51228) vs.
clethodim (RE-45601) acute
oral toxicity
gavage
Sprague-Dawley rats
PMRA #1227467
Study Results
toxicity, ↑bw during the 14 day post-treatment period, no gross tissue
abnormalities (LD50 (♀) > 1400 mg/kg bw).
2) clethodim: 1400 mg/kg bw: severe signs of toxicity (salivation,
decreased motor activity, collapse, hyperactivity, tremors, ↓fc, diarrhoea,
dehydration and nasal, ocular, oral and ano-genital discharges), all animals
died within 3 days, ↓bw day 0-2, necropsy showed red discolored lungs,
blood pooled beneath the cranial meninges and black discolored spleen,
gastric mucosa, intestine and caecum
5-OH sulphone is considerably less toxic than clethodim.
Plant Metabolites:
NOAEL = 70.9 mg/kg bw/day (1000 ppm)
Imine sulfone (RE-47719) 5week oral (dietary) toxicity
study
LOAEL = 604/723 mg/kg bw/day (8000 ppm) based on ↑cholesterol,
↑liver wt. ; ↓bwg (♂- wk. 1), ↓fc (♂- wk. 1), ↑reticulocytes (♂)
Sprague-Dawley rats
PMRA #1227357
Plant Metabolites:
NOAEL ≥588 mg/kg bw/day (8000 ppm)
5-OH sulfone (RE-51228)
LOAEL not established
5-week oral (dietary) toxicity
study
No toxic effects were observed
Sprague-Dawley rats
PMRA #1227358
Plant Metabolites:
Maternal
Imine sulfone (RE-47719)
≥100 mg/kg bw/day: ↓bwg
Developmental toxicity study
700 mg/kg bw/day: clinical signs (excessive salivation), ↓fc (during
dosing),
gavage
Sprague Dawley rats
PMRA #1227359
Developmental
700 mg/kg bw/day: ↓bw, ↑incidence of fetal variations [↑cervical rib
present (per litter); ↓average number of sternal centers (ossification sites
per fetus per litter)]
Supplementary (screening; n=10)
Proposed Re-evaluation Decision - PRVD2016-11
Page 46
Appendix III
Study Type/Animal/PMRA #
Study Results
Plant Metabolites:
Maternal
5-OH sulfone (RE-51228)
700 mg/kg bw/day: clinical signs (rales, excessive salivation)
Developmental toxicity study
gavage
Developmental
5-OH sulfone was not toxic to the fetus
Sprague Dawley rats
Supplementary (screening; n=10)
PMRA #1227360
Plant Metabolites:
negative
Imine sulfone (RE-47719)
Ames test
S. typhimurium TA98, TA100,
TA1535, TA1537, E. coli WP2
uvrA
PMRA #1227361
Plant Metabolites:
negative
Imine sulfone (RE-47719)
Chromosome aberrations in
CHO cells
Chinese Hamster Ovary (CHO)
Cells
PMRA #1227362
Plant Metabolites:
negative
5-OH sulfone (RE-51228)
Ames test
S. typhimurium TA98, TA100,
TA1535, TA1537, E. coli WP2
uvrA
PMRA #1229446
Proposed Re-evaluation Decision - PRVD2016-11
Page 47
Appendix III
Study Type/Animal/PMRA #
Study Results
Plant Metabolites:
negative
5-OH sulfone (RE-51228)
Chromosome aberrations in
CHO cells
Chinese Hamster Ovary (CHO)
Cells
PMRA #1229458
Table 2 Toxicology Endpoints for Use in Health Risk Assessment for Clethodim
Point of Departure and
CAF1 or
Endpoint
Target MOE
Acute dietary
Acute oral neurotoxicity
NOAEL = 100 mg/kg bw
100
study - rats
Clinical signs of toxicity: reduced
activity, hunched posture,
abnormal gait, salivation, head tilt
ARfD = 1.0 mg/kg bw
Chronic dietary
2-year dietary study in
NOAEL = 16 mg/kg bw/day
100
the rat
Liver toxicity, ↓bw, ↑incidence of
chronic pancreatitis
ADI = 0.16 mg/kg bw/day
Short/Intermediate90-day dietary rat
NOAEL = 25 mg/kg bw/day ↓bw, 100
term inhalation2
kidney effects, ↑liver wt.,
hepatocellular hypertrophy
Short/Intermediate28-day dermal rat
NOAEL = 100 mg/kg bw/day
100
term dermal
↓bw, ↑liver wt., urogenital
discharge
Cancer
No evidence of carcinogenicity
1
CAF (composite assessment factor) refers to a total of uncertainty and Pest Control Products Act factors for
dietary assessments; MOE refers to a target MOE for occupational assessments.
2
An oral NOAEL was selected, and an inhalation absorption factor of 100% (default value) was used in route-toroute extrapolation.
Exposure Scenario
Study
Proposed Re-evaluation Decision - PRVD2016-11
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Appendix IV
Appendix IV
Agricultural Mixer/Loader/Applicator and
Postapplication Risk Assessment
Table 1 Occupational Mixer/Loader/Applicator Exposure and Risk Assessment (Baseline
PPE)
Crop
Canola, flax,
lentil, mustard,
pea, potato,
soybean,
sunflower
Chickpea
Application
Equipment
Groundboom
Aerial
Groundboom
Aerial
Alfalfa seedling,
safflower
Beans (dry)
Groundboom
Groundboom
Aerial
Coriander,
fenugreek, onions
Prairie carnation,
spinach
Blueberry (high
bush)
Groundboom
Groundboom
Scenario
ATPDa
Farmer
Custom
Mixer/loader
Applicator
107 ha
360 ha
400 ha
Farmer
Custom
Mixer/loader
Applicator
Farmer
Custom
Farmer and
Custom
Mixer/loader
Applicator
Farmer and
Custom
Farmer and
Custom
Farmer and
Custom
107 ha
360 ha
400 ha
45.6 g ai/ha
107 ha
360 ha
26 ha
91.2 g ai/ha
Application
Rateb
91.2 g ai/ha
MOE (Target = 100)
Dermalc Inhalationd Combinede
9800
80,000
8730
2910
23,800
2600
4290
34,300
3810
22,700
783,000
22,100
45.6 g ai/ha
19,600
5830
8580
45,400
9800
2910
80,700
160,000
47,600
68,500
1,570,000
80,000
23,800
659,000
17,500
5200
7600
44,100
8730
2600
71,900
26 ha
91.2 g ai/ha
8580
45,400
40,300
68,500
1,570,000
329,000
7620
44,100
35,900
26 ha
45.6 g ai/ha
80,700
659,000
71,900
400 ha
Groundboom
26 ha
91.2 g ai/ha
40,300
329,000
35,900
LPHW
1.5 ha
62,000
323,000
52,000
Backpack
10,700
235,000
10,300
Cranberry
Groundboomf Farmer and
107 ha 91.2 g ai/ha
9800
80,000
8730
Custom
HPHW
35 ha
455
4200
410
LPHW
1.5 ha
68,200
356,000
57,200
Backpack
11,800
259,000
11,300
ATPD = area treated per day, LPHW = manually pressurized handwand, HPHW = mechanically pressurized
handgun
a
Default areas from the PMRA ATPD table were used. For handheld equipment, the default values for amount
handled per day (L/ha) were converted to areas using the minimum spray volume on the label (100 L/ha for
blueberries and 110 L/ha for cranberries).
b
Maximum label application rate
c
Dermal MOEs are based on a dermal NOAEL of 100 mg/kg bw/day. Target is 100. Dermal MOE = NOAEL/ (Unit
Exposure (µg/kg ai) * ATPD * Application Rate / Body Weight (80 kg)). Unit exposure values are from PHED.
d
Inhalation MOEs are based on an oral NOAEL of 25 mg/kg bw/day. Target is 100. Inhalation MOE = NOAEL/
(Unit Exposure (µg/kg ai) * ATPD * Application Rate / Body Weight (80 kg)). Unit exposure values are from
PHED.
e
Calculated using the following equation: Combined MOE =1/(1/MOEdermal)+(1/MOEinhalation)).
f
Groundboom included as potential application equipment in the minor use assessment.
Proposed Re-evaluation Decision - PRVD2016-11
Page 49
Appendix IV
Table 2 Postapplication Exposure and Risk Assessment
Crop
TC a
(cm2/hr)
Application
Rate b
Alfalfa seedling, high bush
blueberry, lentil, coriander,
fenugreek, mustard, pea, potato,
safflower
Chickpea, bean
Spinach
1750
91.2 g ai/ha
DFRc
(µg/cm2)
0.228
Day 0
Exposured
(mg/kg bw/day)
0.0180
MOEe
(Target = 100)
2510
1750
1750
45.6 g ai/ha
0.114
0.00898
5010
45.6 g ai/ha
0.140
0.0110
4080
(two apps)f
Flax, soybean, canola, cranberry
1100
91.2 g ai/ha
0.228
0.0113
4000
Prairie carnation
1100
45.6 g ai/ha
0.114
0.00564
7970
Onion
4400
91.2 g ai/ha
0.228
0.0451
997
Sunflower
90
91.2 g ai/ha
0.228
0.000923
48,700
a
TC = transfer coefficient. The highest TC for each crop was included in this table. See Table 3 below for a list of
the activities and additional TCs for each crop.
b
Maximum label application rate
c
DFR= dislodgeable foliar residue. The default peak DFR value of 25% of the application rate was assumed.
d
Dermal exposure = TC * DFR * 8 hours / Body Weight (80 kg).
e
MOE = margin of exposure. MOE = NOAEL/exposure. Dermal MOEs are based on a dermal NOAEL of 100
mg/kg bw/day. Target is 100.
f
Two applications, 14 days apart. The default 10% dissipation rate was assumed.
Table 3 Summary of Transfer Coefficient for Clethodim
Crop
Alfalfa seedling, bean
(dry), pea (field), lentila
Canola, flax, prairie
carnationb
Soybean
Chickpea, safflower
Corianderc, fenugreekc,
mustard, spinach
Sunflower
Onion (dry)
Activity
Irrigation (hand set)
Scouting
Mechanical harvesting, mechanical swathing (beans, peas), mechanical
knifing (beans, peas), mechanical weeding (beans, peas), fertilizing,
irrigation (non-hand set)
Scouting
Mechanical harvesting, irrigation (non-hand set)
Scouting
Hand weeding
Mechanical harvesting, mechanical weeding (soybean), mechanical
swathing (buckwheat), bailing straw (buckwheat), irrigation (nonhandset)
Irrigation (hand set)
Scouting
Hand weeding
Mechanical harvesting, mechanical knifing, mechanical swathing,
mechanical weeding, fertilizing, irrigation (non-hand set)
Irrigation (hand set)
Hand harvesting
Hand weeding
Scouting
Transplanting
Mechanical harvesting, mechanical weeding, irrigation (non-hand set)
Scouting, bird control
Mechanical harvesting
Hand weeding
Proposed Re-evaluation Decision - PRVD2016-11
Page 50
TC (cm2/hr)
1750
1100
0
1100
0
1100
70
0
1750
1100
70
0
1750
1100
70
210
230
0
90
0
4400
Appendix IV
Table 3 Summary of Transfer Coefficient for Clethodim
Crop
Potato
Blueberry (high bush)
Cranberry
Activity
Irrigation (hand set)
Scouting, thinning
Mechanical harvesting, mechanical weeding, irrigation (non-hand set)
Irrigation (hand set)
Roguing
Scouting
Hand weeding
Mechanical harvesting, mechanical weeding, irrigation (non-hand set)
Irrigation (hand set)
Hand pruning, scouting, bird control, hand weeding, frost control
Transplanting
Mechanical harvesting, mechanical weeding, irrigation (non-hand set)
Hand harvesting (raking), scouting
Transplanting
Hand pruning (shears), hand weeding
Mechanical harvesting (flood), mechanical weeding, sanding, ditching,
frost control, irrigation (non-hand set)
TC = transfer coefficient
a
Beans(dry) were used as a surrogate crop for lentils
b
Canola was used as surrogate crop for prairie carnation
c
Parsley was used as a surrogate crop for coriander and fenugreek
Proposed Re-evaluation Decision - PRVD2016-11
Page 51
TC (cm2/hr)
1750
1300
0
1750
1000
210
70
0
1750
640
230
0
1100
230
70
0
Appendix IV
Proposed Re-evaluation Decision - PRVD2016-11
Page 52
Appendix V
Appendix V
Dietary Exposure and Risk Estimates for Clethodim
Table 1 Summary of Acute Dietary Exposure and Risk from Clethodim
Acute Dietary (95th percentile)1
Population Subgroup
Food only
Exposure
(mg/kg bw)
General Population
0.034374
All Infants
0.057396
Children 1-2 years old
0.070148
Children 3-5 years old
0.067183
Children 6-12 years old
0.042608
Youth 13-19 years old
0.025700
Adults 20-49 years old
0.023880
Adults 50-99 years old
0.023018
Females 13-49 years old
0.023884
1
Acute Reference Dose (ARfD) of 1 mg/kg bw.
Food + Water
%ARfD
3.44
5.74
7.01
6.72
4.26
2.57
2.39
2.30
2.39
Exposure
(mg/kg bw)
0.035492
0.060795
0.071939
0.069079
0.043691
0.026494
0.024942
0.023917
0.025101
%ARfD
3.55
6.08
7.19
6.91
4.37
2.65
2.49
2.39
2.51
Table 2 Summary of Chronic Dietary Exposure and Risk from Clethodim
Chronic Dietary1
Population Subgroup
Food only
Exposure
(mg/kg bw/day)
General Population
0.013072
All Infants
0.025133
Children 1-2 years old
0.037578
Children 3-5 years old
0.031078
Children 6-12 years old
0.019182
Youth 13-19 years old
0.010942
Adults 20-49 years old
0.010470
Adults 50-99 years old
0.010172
Females 13-49 years old
0.010321
1
Acceptable Daily Intake (ADI) of 0.16 mg/kg bw/day.
Food + Water
%ADI
8.2
15.7
23.5
19.4
12.0
6.8
6.5
6.4
6.5
Exposure
(mg/kg bw/day)
0.013930
0.027347
0.038817
0.032121
0.019935
0.011568
0.011327
0.011018
0.011174
Table 3 Dietary Input Characterization for Clethodim
Food Commodity
Alfalfa, seed
Amaranth, Leafy
Arrowroot, flour
Artichoke, globe
Arrowroot, flour-babyfood
Artichoke, Jerusalem
Arugula
Asparagus
Balsam pear
Basil, dried leaves
Basil, dried leaves-babyfood
Residues
0.1
2
1
1.2
1
1
2
1.7
0.5
12
12
Source
CDN GMRL
US Tolerance for subgroup 4A
US Tolerance for subgroup 1C
US Tolerance
US Tolerance for subgroup 1C
US Tolerance for subgroup 1C
US Tolerance for subgroup 4A
US Tolerance
US Tolerance for subgroup 9B
US Tolerance for subgroup 19A
US Tolerance for subgroup 19A
Proposed Re-evaluation Decision - PRVD2016-11
Page 53
%ADI
8.7
17.1
24.3
20.1
12.5
7.2
7.1
6.9
7.0
Appendix V
Food Commodity
Basil, fresh leaves
Basil, fresh leaves-babyfood
Bean, black, seed
Bean, broad, succulent
Bean, broad, seed
Bean, cowpea, succulent
Bean, cowpea, seed
Bean, great northern, seed
Bean, kidney, seed
Bean, lima, succulent
Bean, lima, seed
Bean, mung, seed
Bean, navy, seed
Bean, pink, seed
Bean, pinto, seed
Bean, snap, succulent
Bean, snap, succulent-babyfood
Beef, meat
Beef, meat-babyfood
Beef, meat, dried
Beef, meat byproducts
Beef, meat byproducts-babyfood
Beef, fat
Beef, fat-babyfood
Beef, kidney
Beef, liver
Beef, liver-babyfood
Beet, garden, roots
Beet, garden, roots-babyfood
Beet, sugar
Beet, sugar-babyfood
Beet, sugar, molasses
Beet, sugar, molasses-babyfood
Blackberry
Blackberry, juice
Blackberry, juice-babyfood
Blueberry
Blueberry-babyfood
Broccoli
Broccoli-babyfood
Broccoli, Chinese
Broccoli raab
Brussels sprouts
Burdock
Cabbage
Cabbage, Chinese, bok choy
Cabbage, Chinese, napa
Cabbage, Chinese, mustard
Cantaloupe
Cardoon
Carrot
Carrot-babyfood
Carrot, juice
Residues
12
12
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
1
1
0.2
0.2
1
1
0.3
0.3
0.3
0.2
0.2
3
3
3
3
3
1
3
3
3
3
2
0.6
1
1
1
Source
US Tolerance for subgroup 19A
US Tolerance for subgroup 19A
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance for subgroup 1B
US Tolerance for subgroup 1B
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance for subgroup 13-07A
US Tolerance for subgroup 13-07A
US Tolerance for subgroup 13-07A
CDN MRL
CDN MRL
US Tolerance for subgroup 5A
US Tolerance for subgroup 5A
US Tolerance for subgroup 5A
US Tolerance for subgroup 5B
US Tolerance for subgroup 5A
US Tolerance for subgroup 1B
US Tolerance for subgroup 5A
US Tolerance for subgroup 5B
US Tolerance for subgroup 5A
US Tolerance for subgroup 5A
US Tolerance for subgroup 9A
US Tolerance for subgroup 4B
US Tolerance for subgroup 1B
US Tolerance for subgroup 1B
US Tolerance for subgroup 1B
Proposed Re-evaluation Decision - PRVD2016-11
Page 54
Appendix V
Food Commodity
Cassava
Cassava-babyfood
Cauliflower
Celeriac
Celery
Celery-babyfood
Celery, juice
Celtuce
Chayote, fruit
Chicken, meat
Chicken, meat-babyfood
Chicken, liver
Chicken, meat byproducts
Chicken, meat byproducts-babyfood
Chicken, fat
Chicken, fat-babyfood
Chicken, skin
Chicken, skin-babyfood
Chickpea, seed
Chickpea, seed-babyfood
Chickpea, flour
Chicory, roots
Chinese waxgourd
Chrysanthemum garland
Collards
Coriander, seed
Coriander, seed-babyfood
Corn, field, flour
Corn, field, flour-babyfood
Corn, field, meal
Corn, field, meal-babyfood
Corn, field, bran
Corn, field, starch
Corn, field, starch-babyfood
Corn, field, syrup
Corn, field, syrup-babyfood
Corn, field, oil
Corn, field, oil-babyfood
Corn, pop
Cottonseed, oil
Cottonseed, oil-babyfood
Cranberry
Cranberry-babyfood
Cranberry, dried
Cranberry, juice
Cranberry, juice-babyfood
Cress, garden
Cress, upland
Cucumber
Currant
Currant, dried
Dandelion, leaves
Dasheen, corm
Residues
1
1
3
1
0.6
0.6
0.6
0.6
0.5
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
3.5
3.5
3.5
1
0.5
2
3
3
3
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.5
0.5
0.5
0.5
0.5
0.5
0.5
2
2
0.5
0.2
0.2
2
1
Source
US Tolerance for subgroup 1C
US Tolerance for subgroup 1C
US Tolerance for subgroup 5A
US Tolerance for subgroup 1B
US Tolerance for subgroup 4B
US Tolerance for subgroup 4B
US Tolerance for subgroup 4B
US Tolerance for subgroup 4B
US Tolerance for subgroup 9B
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for subgroup 1B
US Tolerance for subgroup 9B
US Tolerance for subgroup 4A
US Tolerance for subgroup 5B
CDN MRL
CDN MRL
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
CODEX
CODEX
CDN MRL
CDN MRL
CDN MRL
CDN MRL
CDN MRL
US Tolerance for subgroup 4A
US Tolerance for subgroup 4A
US Tolerance for subgroup 9B
CDN MRL
CDN MRL
US Tolerance for subgroup 4A
US Tolerance for subgroup 1C
Proposed Re-evaluation Decision - PRVD2016-11
Page 55
Appendix V
Food Commodity
Dill, seed
Dillweed
Egg, whole
Egg, whole-babyfood
Egg, white
Egg, white (solids)-babyfood
Egg, yolk
Egg, yolk-babyfood
Eggplant
Elderberry
Endive
Fennel, Florence
Flax seed, oil
Garlic, bulb
Garlic, bulb-babyfood
Ginger
Ginger-babyfood
Ginger, dried
Ginseng, dried
Goat, meat
Goat, meat byproducts
Goat, fat
Goat, kidney
Goat, liver
Gooseberry
Guava
Guava-babyfood
Herbs, other
Herbs, other-babyfood
Honeydew melon
Hop
Horse, meat
Horseradish
Huckleberry
Kale
Kohlrabi
Lentil, seed
Lettuce, head
Lettuce, leaf
Loganberry
Meat, game
Milk, fat
Milk, fat-baby food/infant formula
Milk, nonfat solids
Milk, nonfat solids-baby food/infant formula
Milk, water
Milk, water-babyfood/infant formula
Milk, sugar (lactose)-baby food/infant formula
Mustard greens
Onion, bulb
Onion, bulb-babyfood
Onion, bulb, dried
Onion, bulb, dried-babyfood
Residues
12
12
0.2
0.2
0.2
0.2
0.2
0.2
1
0.2
2
0.6
0.6
0.5
0.5
1
1
1
1
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
12
12
2
0.5
0.2
1
0.2
3
3
3.5
2
2
0.3
0.2
0.1
0.1
0.1
0.1
0.1
0.1
0.1
3
0.2
0.2
0.2
0.2
Source
US Tolerance for subgroup 19A
US Tolerance for subgroup 19A
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance for group 8
CDN MRL
US Tolerance for subgroup 4A
US Tolerance for subgroup 4B
US Tolerance
CODEX
CODEX
US Tolerance for subgroup 1C
US Tolerance for subgroup 1C
US Tolerance for subgroup 1C
US Tolerance for subgroup 1B
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
CDN MRL
CDN MRL
CDN MRL
US Tolerance for Herb subgroup 19A
US Tolerance for Herb subgroup 19A
US Tolerance for subgroup 9A
US Tolerance
US Tolerance
US Tolerance for subgroup 1B
CDN MRL
US Tolerance for subgroup 5B
US Tolerance for subgroup 5A
US Tolerance for group 6
US Tolerance for subgroup 4A
US Tolerance for subgroup 4A
US Tolerance for subgroup 13-07A
CODEX
CDN GMRL
CDN GMRL
CDN GMRL
CDN GMRL
CDN GMRL
CDN GMRL
CDN GMRL
US Tolerance for subgroup 5B
CDN MRL
CDN MRL
CDN MRL
CDN MRL
Proposed Re-evaluation Decision - PRVD2016-11
Page 56
Appendix V
Food Commodity
Onion, green
Parsley, turnip rooted
Parsnip
Parsnip-babyfood
Pea, dry
Pea, dry-babyfood
Pea, pigeon, seed
Peach
Peach-babyfood
Peach, dried
Peach, dried-babyfood
Peach, juice
Peach, juice-babyfood
Peanut
Peanut, butter
Peanut, oil
Pepper, bell
Pepper, bell-babyfood
Pepper, bell, dried
Pepper, bell, dried-babyfood
Pepper, nonbell
Pepper, nonbell-babyfood
Pepper, nonbell, dried
Peppermint
Peppermint, oil
Pork, meat
Pork, meat-babyfood
Pork, skin
Pork, meat byproducts
Pork, meat byproducts-babyfood
Pork, fat
Pork, fat-babyfood
Pork, kidney
Pork, liver
Potato, chips
Potato, dry (granules/ flakes)
Potato, dry (granules/ flakes)-babyfood
Potato, flour
Potato, flour-babyfood
Potato, tuber, w/peel
Potato, tuber, w/peel-babyfood
Potato, tuber, w/o peel
Potato, tuber, w/o peel-babyfood
Poultry, other, meat
Poultry, other, liver
Poultry, other, meat byproducts
Poultry, other, fat
Poultry, other, skin
Pumpkin
Pumpkin, seed
Rabbit, meat
Radicchio
Radish, roots
Residues
2
1
1
1
3.5
3.5
3.5
0.2
0.2
0.2
0.2
0.2
0.2
3
3
3
1
1
1
1
1
1
1
5
5
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.5
2
2
0.5
0.5
0.5
0.5
0.5
0.5
0.2
0.2
0.2
0.2
0.2
0.5
0.5
0.2
2
1
Source
US Tolerance
US Tolerance for subgroup 1B
US Tolerance for subgroup 1B
US Tolerance for subgroup 1B
US Tolerance for group 6
US Tolerance for group 6
US Tolerance for group 6
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
CDN MRL
US Tolerance
US Tolerance
CDN MRL
CDN MRL
CDN MRL
CDN MRL
CDN MRL
CDN MRL
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance for subgroup 9B
US Tolerance for subgroup 9B
CODEX
US Tolerance for subgroup 4A
US Tolerance for subgroup 1B
Proposed Re-evaluation Decision - PRVD2016-11
Page 57
Appendix V
Food Commodity
Radish, tops
Radish, Oriental, roots
Rape greens
Rapeseed, oil
Rapeseed, oil-babyfood
Raspberry
Raspberry-babyfood
Raspberry, juice
Raspberry, juice-babyfood
Rhubarb
Rutabaga
Safflower, oil
Safflower, oil-babyfood
Salsify, roots
Sesame, seed
Sesame, seed-babyfood
Sesame, oil
Sesame, oil-babyfood
Sheep, meat
Sheep, meat-babyfood
Sheep, meat byproducts
Sheep, fat
Sheep, fat-babyfood
Sheep, kidney
Sheep, liver
Soybean, seed
Soybean, flour
Soybean, flour-babyfood
Soybean, soy milk
Soybean, soy milk-babyfood or infant formula
Soybean, oil
Soybean, oil-babyfood
Spearmint
Spearmint, oil
Spices, other
Spices, other-babyfood
Spinach
Spinach-babyfood
Squash, summer
Squash, summer-babyfood
Squash, winter
Squash, winter-babyfood
Strawberry
Strawberry-babyfood
Strawberry, juice
Strawberry, juice-babyfood
Sunflower, seed
Sunflower, oil
Sunflower, oil-babyfood
Sweet potato
Sweet potato-babyfood
Swiss chard
Tanier, corm
Residues
0.7
1
3
0.5
0.5
0.3
0.3
0.3
0.3
0.6
1
5
5
1
0.35
0.35
0.35
0.35
0.2
0.2
0.2
0.2
0.2
0.2
0.2
10
10
10
10
10
10
10
5
5
0.7
0.7
2
2
0.5
0.5
0.5
0.5
3
3
3
3
5
5
5
1
1
0.6
1
Source
US Tolerance
US Tolerance for subgroup 1B
US Tolerance for subgroup 5B
US Tolerance
US Tolerance
US Tolerance for subgroup 13-07A
US Tolerance for subgroup 13-07A
US Tolerance for subgroup 13-07A
US Tolerance for subgroup 13-07A
US Tolerance for subgroup 4B
US Tolerance for subgroup 1B
US Tolerance
US Tolerance
US Tolerance for subgroup 1B
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
CDN MRL
CDN MRL
CDN MRL
CDN MRL
CDN MRL
CDN MRL
CDN MRL
US Tolerance
US Tolerance
CDN MRL for Fenugreek, seed
CDN MRL for Fenugreek, seed
CDN MRL
CDN MRL
US Tolerance for subgroup 9B
US Tolerance for subgroup 9B
US Tolerance for subgroup 9B
US Tolerance for subgroup 9B
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance for subgroup 1C
US Tolerance for subgroup 1C
US Tolerance for subgroup 4B
US Tolerance for subgroup 1C
Proposed Re-evaluation Decision - PRVD2016-11
Page 58
Appendix V
Food Commodity
Tomatillo
Tomato
Tomato-babyfood
Tomato, paste
Tomato, paste-babyfood
Tomato, puree
Tomato, puree-babyfood
Tomato, dried
Tomato, dried-babyfood
Tomato, juice
Turkey, meat
Turkey, meat-babyfood
Turkey, liver
Turkey, liver-babyfood
Turkey, meat byproducts
Turkey, meat byproducts-babyfood
Turkey, fat
Turkey, fat-babyfood
Turkey, skin
Turkey, skin-babyfood
Turmeric
Turnip, roots
Turnip, greens
Water, direct, all sources
Water, indirect, all sources
Watermelon
Watermelon, juice
Yam, true
Yam bean
Residues
1
1
1
1
1
1
1
1
1
1
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
1
1
3
0.041
0.041
2
2
1
1
Source
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance for group 8
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance
US Tolerance for subgroup 1C
US Tolerance for subgroup 1B
US Tolerance for subgroup 5B
PMRA #2414981
PMRA #2414981
US Tolerance for subgroup 9A
US Tolerance for subgroup 9A
US Tolerance for subgroup 1C
US Tolerance for subgroup 1C
Proposed Re-evaluation Decision - PRVD2016-11
Page 59
Appendix V
Proposed Re-evaluation Decision - PRVD2016-11
Page 60
Appendix VI
Appendix VI
Food Residue Chemistry Summary
Clethodim, a member of the cyclohexanedione family of herbicide, was evaluated by the JMPR
in 1994, 1997, 1999 and 2002.
Clethodim is currently registered in Canada for post-emergent control of a number of grasses and
weeds on various terrestrial feed and food crops, and for industrial oil seed and fibre crops.
Registered clethodim end-use products are formulated as emulsifiable concentrates or emulsion,
to be applied by ground or aerial equipment.
The nature of the residue in livestock and plant commodities is adequately understood based on
metabolism studies in goats, laying hens, soybeans, carrots, and cotton. In Canada, the residue
definition in plant and animal commodities is currently expressed as the parent clethodim and
metabolites containing the 2-cyclohex-1-enone moiety.
Clethodim shares a common moiety with sethoxydim, another herbicide currently registered in
Canada. This common moiety accounts for the major part of their structures, which differ in two
parts: the oxime oxygen bears an ethyl group in sethoxydim but a 3-chloroallyl group in
clethodim, and the imino carbon bears an n-propyl group in sethoxydim but an ethyl group in
clethodim. Sethoxydim has been re-evaluated under Re-evaluation Program 1 (PRVD2007-17;
RVD2008-10) and granted continued registration.
Analytical methods have been previously reviewed by the PMRA. The common moiety method
RM-26A (PMRA# 1232663) has been used to analyse clethodim residues in plant and animal
matrices. Method RM-26A and modifications thereof were deemed adequate for data gathering.
RM-26A-1 and RM-26B-3 are enforcement methods for plant and animal matrices. However,
RM-26B-3 cannot distinguish between residues of clethodim (and its metabolites) and
sethoxydim (and its metabolites). These methods were used by independent laboratories and
considered to have been successfully validated. Additionally, a method specific to clethodim is
listed under the U.S. FDA’s Pesticide Analytical Manual Volume II.
Overall, available field trial data for registered crops support the established MRLs. However,
confined crop rotation data on file are inadequate to support the establishment of plant back
intervals. Therefore, a restriction against crop rotation should be added to clethodim labels.
Proposed Re-evaluation Decision - PRVD2016-11
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Appendix VI
Proposed Re-evaluation Decision - PRVD2016-11
Page 62
Appendix VII
Appendix VII
Supplemental Maximum Residue Limit Information –
International Situation and Trade Implications
Maximum residue limits (MRLs) may vary from one country to another for a number of reasons,
including differences in pesticide use patterns and the locations of the field crop trials used to
generate residue chemistry data. For animal commodities, differences in MRLs can be due to
different livestock feed items and practices.
Table 1 Comparison between MRLs in Canada and in Other Jurisdictions
Crop
Alfalfa, fodder
Alfalfa, forage
Alfalfa, hay
Alfalfa, Seedling
Aronia berries
Artichoke, globe
Asparagus
Beans
Beans, dry
Bean, fodder
Beans, except broad bean and
soybean
Bearberries
Beet, fodder
Beet, sugar
Beet, sugar, molasses
Beet, sugar, roots
Beet, sugar, tops
Bilberries
Brassica, head and stem,
subgroup 5A
(includes broccoli, broccoli
Chinese, brussels sprouts,
cabbage except Chinese bok
choy cabbage, cauliflower,
kohlrabi)
Brassica, leafy greens,
subgroup 5B
(includes broccoli raab,
Chinese bok choy cabbage,
collards, kale, mustard greens,
rape greens, turnip greens)
Canadian MRL
(ppm)
*
0.2
0.5
-
U.S. Tolerance
(ppm)
6
10
0.2
1.2
1.7
2.5
-
-
-
0.5
0.5
0.5
1
0.2
1
-
0.1
0.1
-
-
3
-
-
3
-
Proposed Re-evaluation Decision - PRVD2016-11
Page 63
Codex MRL (ppm)
10
2
10
Appendix VII
Crop
Caneberry subgroup 13-07A
(includes blackberry,
loganberry, black, red and
wild raspberry)
Cattle, fat
Cattle, meat
Cattle, meat byproducts
Chilean guavas
Cloudberries
Clover, forage
Clover, hay
Coriander seeds
Corn, field, forage
Corn, field, grain
Corn, field, stover
Cotton, meal
Cotton, undelinted seed
Cotton, seed
Cotton seed oil, Crude
Cotton seed oil, Edible
Cranberries
Currants
Currants, Buffalo
Dry chickpeas
Dry lentils
Dry peas
Edible offal (mammalian)
Eggs
Elderberries
European barberries
Fenugreek seeds
Flax, meal
Flaxseeds
Garlic
Goat, fat
Goat, meat
Goat, meat byproducts
Gooseberries
Herb subgroup 19A
(includes basil, dillweed)
Highbush blueberries
Canadian MRL
(ppm)
U.S. Tolerance
(ppm)
Codex MRL (ppm)
-
0.3
-
0.2
0.5
3
0.5
0.2
0.2
0.5
0.5
0.5
0.2
0.2
0.7
0.3
0.2
0.2
0.2
0.2
0.2
10
20
0.2
0.2
0.2
2
1
0.5
0.2
0.2
0.2
0.2
0.2
1
0.6
0.2
0.2
0.2
0.2
0.5
0.5
0.5
2
0.2
0.05
0.5
-
-
12
-
0.2
0.2
-
Proposed Re-evaluation Decision - PRVD2016-11
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Appendix VII
Crop
Highbush cranberries
Hog, fat
Hog, meat
Hog, meat byproducts
Honeysuckle
Hop, dried cones
Horse, fat
Horse, meat
Horse, meat byproducts
Huckleberries
Jostaberries
Leaf petioles subgroup 4B
(includes cardoon, celery,
celtuce, florence fennel,
rhubarb, swiss chard)
Leafy greens subgroup 4A
(includes, amaranth, arugula,
chervil, chrysanthemum
edible-leaved, chrysanthemum
garland, cress garden, cress
upland, dandelion, endive,
lettuce leaf ,lettuce head,
parsley, radicchio, spinach)
Lingonberries
Lowbush blueberries
Meat (from mammals other
than marine mammals)
Melon subgroup 9A
(includes cantaloupe,
honeydew melon, watermelon)
Milk
Muntries
Mustard seeds (condiment
type)
Mustard seeds (oilseed type)
Mustard, Yellow
Onion, bulb
Onion, green
Partridgeberries
Peach
Peanut
Peanut, hay
Peanut, meal
Canadian MRL
(ppm)
0.2
0.2
0.2
0.2
U.S. Tolerance
(ppm)
0.2
0.2
0.2
0.2
0.2
0.5
0.2
0.2
0.2
0.2
0.2
-
0.6
-
-
2
-
0.5
0.2
0.2
0.2
-
-
-
0.2
-
2
-
0.5
0.05
-
0.05
-
0.4
-
-
0.05
*
0.2
0.5
-
0.5
0.2
2
0.2
3
3
5
0.5
5
-
Proposed Re-evaluation Decision - PRVD2016-11
Page 65
Codex MRL (ppm)
-
Appendix VII
Crop
Peppermint, tops
Potatoes
Potato, granules/flakes
Poultry, fat
Poultry, meat
Poultry, meat byproducts
Poultry, Edible offal of
Prairie Carnation
Radish, tops
Rapeseeds (canola, seed)
Canola, meal
Rapeseed oil, Crude
Rapeseed oil, Edible
Safflower, seed
Safflower, meal
Salal berries
Saskatoon berries (juneberries)
Sea buckthorn
Sesame, seed
Sheep, fat
Sheep, meat
Sheep, meat byproducts
Soybean (Dry)
Soyabean oil, Crude
Soyabean oil, Refined
Spearmint, tops
Spinach
Squash/cucumber subgroup 9B
(includes chayote fruit,
Chinese waxgourd, cucumber,
balsam apple, balsam pear,
pumpkin, squash)
Strawberry
Sunflower, meal
Sunflower, seeds
Sundflower seed oil, Crude
Tomato
Vegetable, fruiting group 8
(include eggplant, pepper,
tomatillo, tomato)
Vegetable, legume, group 6,
except soybean
Canadian MRL
(ppm)
0.5
N/A
0.05
*
0.2
0.2
0.2
10
2
U.S. Tolerance
(ppm)
5
0.5
2
0.2
0.2
0.2
0.7
0.5
1
5
10
0.2
0.2
0.2
0.35
0.2
0.2
0.2
10
5
2
-
0.5
-
0.2
-
3
10
5
1
0.5
0.1
1
-
1
-
-
3.5
-
Proposed Re-evaluation Decision - PRVD2016-11
Page 66
Codex MRL (ppm)
0.5
0.2
0.2
0.5
0.5
0.5
10
1
0.5
-
Appendix VII
Crop
(include succulent and dried
peas, beans)
Vegetable, root, except sugar
beet, subgroup 1B
(includes garden beet,
burdock, carrot, celeriac,
chicory, ginseng, horseradish,
parsley, parsnip, radish,
radish oriental, rutabaga,
salsify, turnip)
Vegetable, tuberous and corm,
subgroup 1C
(includes arrowroot, artichoke
Jerusalem, cassava, chayote
(root), dasheen, ginger, potato,
sweet potato, tanier, turmeric,
yam bean, yam true)
Canadian MRL
(ppm)
U.S. Tolerance
(ppm)
Codex MRL (ppm)
-
1
-
-
1
-
*No MRLs were specified for the following registered crops: alfalfa seedling, mustard yellow and safflower. Residues in/on
these crops are covered under Part B, Division 15, subsection B.15.002(1) of the Food and Drug Regulations as 0.1 ppm.



Canadian MRLs website: http://pr-rp.hc-sc.gc.ca/mrl-lrm/index-eng.php
CODEX MRLs website: http://www.codexalimentarius.net/pestres/data/index.html?lang=en
U.S. Tolerances website: http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&tpl=/ecfrbrowse/Title40/40cfr180_main_02.tpl
Table 2 Residue Definition in Canada and Other Jurisdictions
Jurisdiction
Canada
Residue Definition
Current
2-[1-[[[(2E)-3-chloro-2-propen-1-yl]oxy]imino]propyl]-5-[2(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one, including
metabolites containing the 2-cyclohex-1-enone moiety
Proposed
Sum of clethodim [(±) -2-[(E)-3-chloroallyoxyimino]propyl]-5-[2(ethylthio)propyl]-3-hydroxycyclohex-2-enone)] and its metabolites
containing the 2-cyclohex-1-enone moiety, expressed as clethodim
United States
2-[(1E)-1-[[[(2E)-3-chloro-2-propenyl]oxy]imino]propyl]-5-[2(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one, and its
metabolites containing the 5-(2-ethylthiopropyl)cyclohexene-3-one
and 5-(2-ethylthiopropyl)-5-hydroxycyclohexene-3-one moieties and
their sulphoxides and sulphones, calculated as the stoichiometric
equivalent of clethodim, in or on the commodity
Codex (JMPR)
Sum of clethodim and its metabolites containing 5-(2ethylthiopropyl)cyclohexene-3-one and 5-(2-ethylthiopropyl)-5hydroxycyclohexene-3-one moieties and their sulphoxides and
sulphones, expressed as clethodim
Proposed Re-evaluation Decision - PRVD2016-11
Page 67
Appendix VII
Proposed Re-evaluation Decision - PRVD2016-11
Page 68
Appendix VIII
Appendix VIII
Environmental Risk Assessment
Table 1 Physical and chemical properties of clethodim
Property
Vapour pressure at 20°C
Resulta
Henry’s law constant at 20°C
1/H = 3.7 × 109
(Evaluator calculated)
pH
λmax (nm)
Neutral: 203,256, 283
Acidic: 207, 258, 261
Basic:
210, 282, 283
No absorbance at λ > 350 nm
pH
4.2
13.0 (mg/L)
7
5.45 g/L
9
58.9 g/Lb
Ultraviolet (UV) / visible
spectrum
Solubility in water at 20°C
Solubility (g/L) in organic
solvents at 25 °C
n-Octanol/water partition
coefficient (Log Kow & Kow) at
20°C
Dissociation constant
Stability
(temperature, metal)
-2
< 1 × 10 mPa
Soluble in most organic solvents
Solvent
Solubility (g/L)
Acetone
> 900
Ethyl acetate
> 900
Hexane
> 900
Dimethylformamide > 900
Methanol
> 1000
pH
Log KowKow
5.35
4.4
2.5 × 104
7
4.14
1.38 × 104
4.16
The half-life of Clethodim Technical
was estimated to be about 9 months at
21-23°C; the rate of decomposition was
estimated to be at about 5.4% per
month.
Thermally unstable; 47.2% loss after 14
days at 54ºC in the dark.
a
Data obtained from Chemistry Review, PMRA 2320917, 2324667
b
PMRA 2416284,
Comment
Low vapor pressure, not likely to
volatilize from soil or water surfaces
Low potential for volatilization from
water amd moist soil.
Low potential for direct
phototransformation
Soluble at acidic pHs; very soluble
at neutral and alkaline pHs
(Solubility is dependent on pH)
Generally soluble in most organic
solvents
Potential for bioaccumulation
Weak acid
Proposed Re-evaluation Decision - PRVD2016-11
Page 69
Appendix VIII
Table 2 Table of maximum formation of transformation products
Code
Chemical name
Chemical
structure
Study
max %AR (day)
%AR at Study End
(study length)
MAJOR (>10%) TRANSFORMATION PRODUCTS
Aerobic soil
Anaerobic soil
Soil photolysis
RE47365
Clethodim
Oxazole
Aqueous photolysis
D=14.2 (2.5) [ring-46]pH-5
D=14.2 (2.5) [ring-46]pH-5
Hydrolysis
50.5(32) pH-5
56 (29 mins) pH-4
50.5(32) pH-5
56 (29 mins) pH-4
Aerobic aquatic
10.6 (3)
0.1(182)
Anaerobic aquatic
1.2 (181)
Field studies
Aerobic soil
RE46261
Anaerobic soil
Soil photolysis
Aqueous photolysis
3-chloro-allyl
alcohol
Hydrolysis
IR=31.3 (15) [Al] pH-7
IR=29.2 (30) [Al] pH7
30.7(30) pH-5
30.7(30) pH-5
IR=31.3 (2.5) [Al] pH5
IR=31.3 (2.5) [Al] pH5
73(3)
39(1)
<1(121)
<1(30)
IR =14.2 (3) [ring-4-6]
pH-7
SS=37.3 (3) [ring-4-6]
pH-7
IR=14.2 (3) [Al] pH-7
SS= 32.7 (1) [Al] pH-7
IR =5.7 (30) [ring-46]pH-7
IR=0.0 (30) [Al] pH-7
SS= 23.4 (1.25) [Al]
pH-7
32.6 (1) whole system
1.9 (196)
Aerobic aquatic
Anaerobic aquatic
Field studies
Aerobic soil
Anaerobic soil
Soil photolysis
Aqueous photolysis
3-chloropropenal
Hydrolysis
Aerobic aquatic
Anaerobic aquatic
Field studies
Aerobic soil
Anaerobic soil
Soil photolysis
Aqueous photolysis
RE45924
Clethodim
sulfoxide
Hydrolysis
Aerobic aquatic
Proposed Re-evaluation Decision - PRVD2016-11
Page 70
Appendix VIII
Code
Chemical name
Chemical
structure
Study
max %AR (day)
%AR at Study End
(study length)
32.4 (1) (water)
Anaerobic aquatic
Field studies
Aerobic soil
16(30)
5.6 (121)
15.1(28) whole system
2.4 (water)
0.5 (42)
11.7 (182)
10 (380)
10(380)
Anaerobic soil
Soil photolysis
RE47253
Aqueous photolysis
Clethodim sulfone
Hydrolysis
Aerobic aquatic
Anaerobic aquatic
Field studies
Aerobic soil
Anaerobic soil
Soil photolysis
RE47797
Clethodim oxazole
sulfone
Aqueous photolysis
Hydrolysis
Aerobic aquatic
<4.2 (water)
Anaerobic aquatic
4.3 (water)
4.3 (water)
27.8 (63)
27(121)
IR =18.2 (2.5) [ring-46] pH-5
SS= 13.5(1) [ring-4-6]
pH-7
IR =18.2 (2.5) [ring-46] pH-5
SS= 9.9(2.5) [ring-46] pH-7
Hydrolysis
21 (29 mins) pH-4
21 (29 mins) pH-4
Aerobic aquatic
27.3 (196) whole
system
27.3 (196)
Field studies
Aerobic soil
Anaerobic soil
Soil photolysis
Aqueous photolysis
RE47686
Clethodim imine
Anaerobic aquatic
Field studies
Aerobic soil
1.6 (14)
Anaerobic soil
Soil photolysis
Aqueous photolysis
RE47718
Clethodim imine
sulfoxide
IR =23(21) [ring-4-6]
pH-7
SS= 19.4 (2.5) [ring-46] pH-5
IR =19.5 (30) [ring-46] pH-7
SS= 6.8 (2.5) [ring-46] pH-7
21.7 (61) whole system
<2.9 (sediment)
1.5 (181)
3.0 (196)
Hydrolysis
Aerobic aquatic
Anaerobic aquatic
Field studies
Other:
Proposed Re-evaluation Decision - PRVD2016-11
Page 71
1.5 (181)
Appendix VIII
Code
Chemical name
RE52453
Chemical
structure
Study
max %AR (day)
%AR at Study End
(study length)
IR =48.9 (30) [ring-46] pH-7
SS= 33.3 (3) [ring-4-6]
pH-9
IR =48.9 (30) [ring-46] pH-7
SS= 33.3 (3) [ring-4-6]
pH-7
IR =11.8 (25) [ring-46] pH-7
SS=10.7 (2) [ring-4-6]
pH-5
IR = 9.5 (30) [ring-46] pH-7
SS=8.4 (2.5) [ring-4-6]
pH-5
Aerobic soil
Anaerobic soil
Soil photolysis
Aqueous photolysis
DME sulfoxide
Hydrolysis
Aerobic aquatic
Anaerobic aquatic
Field studies
Aerobic soil
Anaerobic soil
Soil photolysis
Aqueous photolysis
Imine Ketone
Hydrolysis
Aerobic aquatic
Anaerobic aquatic
Field studies
MINOR (<10%) TRANSFORMATION PRODUCTS
Aerobic soil
6.0 (91)
Anaerobic soil
Soil photolysis
RE47796
Clethodim
oxazole sulfoxide
Aqueous photolysis
SS =8.5 (2.5) [ring-4-6]
pH-5
Hydrolysis
1.2(2.5) pH9
Aerobic aquatic
<4.2 (water)
Anaerobic aquatic
8.5 (120) water
Field studies
Aerobic soil
Anaerobic soil
Soil photolysis
Aqueous photolysis
RE47719
Clethodim imine
sulfone
Hydrolysis
Aerobic aquatic
Anaerobic aquatic
<3.3 (sediment)
0.2 (42)
Field studies
Other:
RE47365
Aerobic soil
2.1 (3)
Anaerobic soil
Proposed Re-evaluation Decision - PRVD2016-11
Page 72
SS =8.5 (2.5) [ring-46] pH-5
7.3 (181)
Appendix VIII
Code
Chemical name
Chemical
structure
Study
max %AR (day)
%AR at Study End
(study length)
IR =4.3 (1.5) [ring-4-6]
pH-5
IR =4 (2) [ring-4-6]
pH-5
Soil photolysis
Aqueous photolysis
Clethodim
oxazole
Hydrolysis
Aerobic aquatic
7.7 (0.25) water
Anaerobic aquatic
0.0 (196)
1.2 (181)
Field studies
(1E)-I-{2hydroxy-6methoxy-4-[1methyl-2(methylthio)ethyl]
cyclohex-1-one
oxime(CPO)
Aerobic soil
Anaerobic soil
Soil photolysis
Aqueous photolysis
Hydrolysis
2.1 (19 mins)
1.5 (29 mins)
SS =7.5 (0.5) [ring-4-6]
pH-5
SS =2 (2.5) [ring-4-6]
pH-5
Aerobic aquatic
Anaerobic aquatic
Field studies
RE47386
Trione Sulfoxide
Aerobic soil
Anaerobic soil
Soil photolysis
Aqueous photolysis
Hydrolysis
Aerobic aquatic
Anaerobic aquatic
Field studies
D = dark control, IR = Irradiated, SS= Sensitized and Irradiated (sensitized by the addition of acetone), AR = Applied
Radioactivity
Table 3 Fate and behaviour in the environment of clethodim technical grade active
ingredient and its major transformation products clethodim sulfoxide, clethodim
sulfone, clethodim oxazole sulfone and clethodim imine
Property
Test
substance
Abiotic transformation
Hydrolysis
clethodim
Value
Transformation
products
Comments
Reference
25ºC [Pr] EPA
pH 5, DT50: 26 d;
pH 7, DT50: 300 d;
pH 9, DT50: 300 d
Major:
Clethodim
oxazole
Hydrolysis can
contribute to
dissipation of
clethodim
especially in
acidic conditions.
1226985
1074744
25ºC [Pr] Environment
Canada
pH 5, DT50: 28 d;
pH 7, DT50: 300 d;
pH 9, DT50: 310 d
3-chloro-allylalcohol
Chloropropenal3-ol
Clethodim imine
Proposed Re-evaluation Decision - PRVD2016-11
Page 73
Appendix VIII
25ºC [Al]
pH 5, DT50: 42 d;
pH 7, DT50: 360 d;
25ºC[ring-6]
pH 4, DT50: 0.76 d;
pH 7, DT50: 31.3 d;
pH 9, DT50: stable
35ºC[ring-6]
pH 4, DT50: 0.53 d;
pH 7, DT50: 0.56 d;
pH 9, DT50: stable
Phototransformation on soil
clethodim
DT50 (irradiated): 1.521.82 d;
DT50 (dark): 1.87-1.96 d
A phototransformation
half-life could not be
calculated as dissipation
was similar in the dark
controls.
Major, Irradiated:
Clethodim
sulfoxide
Major, Dark:
Clethodim
sulfoxide
Photolysis is not
an important route
of dissipation for
clethodim in the
terrestrial
environment.
1226988
clethodim is nonpersistent
1226990;
1234277;
1226991
Minor, Irradiated:
CO2
Minor, Dark:
CO2
Biotransformation
Biotransforclethodim
mation in
aerobic soil
Clethodim
sulfoxide:
Sandy loam soil at 25ºC
[ring-4,6-14C]:
DT50: 1.23 d; DT90: 4.09
d
[allyl-14C]:
DT50: 1.19 d; DT90:
3.94d
[propyl -14C]:
DT50: 2.47 d; DT90: 8.19
d
Combined labels:
DT50: 1.58 d; DT90: 5.24
d
Major:
Clethodim
sulfoxide,
clethodim
sulfone, CO2,
clethodim oxazole
sulfone,
Minor:
Clethodim
oxazole
Clethodim
oxazole sulfoxide,
clethodim oxazole
sulfone,
Clethodim imine
sulfoxide
[ring-4,6]:
DT50: 15.4 d; DT90: 59.4
d ; tR IORE= 17.9
[allyl]:
DT50: 18.2 d; DT90: 60.4
d
[propyl]:
DT50: 24.7 d; DT90: 81.9
Proposed Re-evaluation Decision - PRVD2016-11
Page 74
Clethodim
sulfoxide is
slightly persistent
Appendix VIII
d
Combined labels:
DT50: 19.9 d; DT90: 66.3
d
Biotransformation in
anaerobic soil
Mobility
Adsorption /
desorption in
soil
Koc mobility
classification
based on
McCall et alet
al (1981
Clethodim
sulfone
[propyl]:
DT50: 22.1 d; DT90: 101
d ; tR IORE= 30.3
Clethodim sulfone
is slightly
persistent.
Clethodim
oxazole
sulfone
[propyl]:
DT50 could not be
determined as residues
were formed late in the
study and was
accumulating at the end
of the study at 380 days.
Clethodim
oxazole sulfone
may be persistent
in aerobic soil
Clethodim
Sandy loam:
DT50: 63.7 d; DT90: 212
d
Clethodim
sulfoxide:
DT50: 8.13 d; DT90: 27 d
Clethodim
imine
DT50 could not be
determined as
concentrations continued
to accumulate at study
termination
Clethodim
Five U.S. soils:
Dallas, Clay loam (pH 8.1, 2.8% OM)
Kd: 0.13; KOC: 7.8
Minor:
Organic volatiles
CO2
Unknown
Bertie, Loamy sand (pH 5.8, 1.0% OM)
Kd: 1.73; KOC: 298.3
Attus, Sand (pH 7.8, 1.3% OM)
Kd: 0.51; KOC: 67.4
Stephenville, Sandy clay loam (pH 7.0, 0.6%
OM)
Kd: 0.32; KOC: 91.2
Fresno, Loamy sand (pH 7.0, 0.4% OM)
Kd: 0.26; KOC: 112.8
Three other soils:
Gleissolo Melanico Aluminico inceptico
(GMa)
(pH 4.0, 33% OM) Kd: 8.61; KOC: 44.97
Latossolo Vermelho Distroferrico tipico
(LVdf)
(pH 4.7, 3.8% OM) Kd: 1.57; KOC: 71.3
Proposed Re-evaluation Decision - PRVD2016-11
Page 75
Clethodim is
moderatleypersistent
1371483
Clethodim
sulfoxide is non
persistent
Clethodim imine
maybe preseistent
in anaerobic soil
Low to very high
mobility in soils.
1226989,
1074746
Appendix VIII
Clethodim
sulfoxide
Latossolo Vermelho Distroferrico psamitico
(LVd) (pH 5.3, 2% OM) Kd: 0.87; KOC: 74.72
Berty, loamy sand (pH 5.8, 1.0% OM)
Kd: 0.26; KOC: 44.48
Clethodim
sulfone
Berty, loamy sand (pH 5.8, 1.0% OM)
Kd: 0.11; KOC: 19.3
Clethodim
oxazole
sulfone
Five soils:
Dallas, Clay loam (pH 8.1, 2.8% OM)
Kd: 10.73; KOC: 660.9
Very high
mobility in soil
Bertie, Loamy sand (pH 5.8, 1.0% OM)
Kd: 0.37; KOC: 63.12
Attus, Sand (pH 7.8, 1.3% OM)
Kd: 1.13; KOC: 149.5
Low to very high
mobility in soils.
Stephenville, Sandy clay loam (pH 7.0, 0.6%
OM)
Kd: 1.65; KOC: 475
Fresno, Loamy sand (pH 7.0, 0.4% OM)
Kd: 2.21; KOC: 951.9
Soil leaching
Volatilization
Field studies
Field
dissipation in
Canada
No acceptable study was submitted. Submitted studies and foreign reviews indicate a 1234274
high potential for vertical mobility/leaching
Not required based on the low vapour pressure (1 × 10-2mPa at 20oC) and Henry’s law constant (6.6
× 10-7 Pa·m3/mol ; 1/H= 3.7 × 107 at 20°C).
Clethodim as
Select 2EC
containing
0.24kg
clethodim/L
Clethodim
sulfoxide,
Clethodim
sulfone,
Clethodim
oxazole sulfoxide,
Clethodim
oxazole sulfone
were detected at
very low
concentrations.
Data could not be
interpreted due to
instability of
clethodim during
storage.
1234270,
1150035,
1140881,
1229455
Value
Transformation
products
Comments
Reference
25ºC [Pr]
pH 5, DT50: 26 d;
pH 7, DT50: 300 d;
pH 9, DT50: 300 d
Major:
Clethodim
oxazole (pH 5)
Hydrolysis can
contribute to the
overall dissipation
of clethodim,
especially at
acidic and neutral
1226985
1074744
10 bare plot sites
DT50 could not be
determined due to
degradation of clethodim
during storage.
Deepest layer analyzed:
0-10 cm
Aquatic systems
Property
Test
substance
Abiotic transformation
Hydrolysis
clethodim
25ºC [Al]
3-chloro-allylalcohol
Proposed Re-evaluation Decision - PRVD2016-11
Page 76
Appendix VIII
pH 5, DT50: 42 d;
pH 7, DT50: 360 d;
25ºC[ring-6]
pH 4, DT50: 0.76 d;
pH 7, DT50: 31.3 d;
pH 9, DT50: stable
pH.
Chloropropenal3-ol
Clethodim imine
35ºC[ring-6]
pH 4, DT50: 0.53 d;
pH 7, DT50: 0.56 d;
pH 9, DT50: stable
Phototransformation in
water
[ring-4-6]-14C
clethodim
Dark system (D)
DT50 (pH 5: 12.5 d;
DT50 (pH 7): 99.4 d
DT50 (pH 9): 330 d
Major : Dark
Clethodim
oxazole
Non-sensitized irradiated
(IR)
DT50 (pH 5: 1.7 d;
DT50 (pH 7): 6.8 d
DT50 (pH 9): 9.6d
Major,(IR):
Clethodim
sulfoxide,
clethodim imine,
clethodim imine
sulfoxide, DME
sulfoxide and
imine ketone
1226986
Minor, (IR)
Trione sulfoxide,
clethodim oxazole
sulfoxide, CO2,
volatile organics
and clethodim
oxazole
[Al]-14C
clethodim
Sensitized irradiated (SS)
DT50 (pH 5: 0.94 d;
DT50 (pH 7): 1.2 d
DT50 (pH 9): 0.52 d
Major,(SS):
Clethodim
sulfoxide,
clethodim imine,
clethodim imine
sulfoxide, DME
sulfoxide
Note:
clethodim imine
sulfoxide and
DME sulfoxide
were still
accumulating in
the environment
at study end (30
d).
Dark system (D)
DT50 (pH 5): 20.1 d;
DT50 (pH 7): 60.9 d
Major : Dark
Chloroallyl
alcohol
Minor Dark
Clethodim
sulfoxide
Proposed Re-evaluation Decision - PRVD2016-11
Page 77
Can be an
important route of
dissipation for
clethodim and its
transformation
products in the
environment
1226987
Appendix VIII
Clethodim
Non-sensitized irradiated
(IR)
DT50 (pH 5: 1.5 d;
DT50 (pH 7): 4.1 d
DT50 (pH 9): 6.0d
Major,(IR):
Clethodim
sulfoxide,
chloroallyly
alcohol and 3chloropropenal
Note:
chloroallyly
alcohol and 3chloropropenal
remained in stable
concentration at
study end (30 d).
Sensitized irradiated (SS)
DT50 (pH 5): 0.20 d;
DT50 (pH 7): 0.61 d
DT50 (pH 9): 0.33 d
Major,(SS):
Clethodim
sulfoxide,
chloroallyly
alcohol and 3chloropropenal
CO2
Direct in ultrapure water
DT50: 28 mins;
Indirect in the presence
of (0.5 -20 mg/L) of
humic acid, nitrates and
Fe (III) ions:
DT50; 2.6 mins to 2.5
days
Biotransformation
BiotransforClethodim
mation in
aerobic watersediment
systems
slough water: sandy clay
loam sediment
dark system at 25°C
Whole system DT50: 5.84
d; DT90: 19.4 d
light system at 25°C
Whole system DT50: 4.32
d; DT90: 14.4 d
dark system at 5°C
Whole system DT50: 9.6
d; DT90: 155 d (slow t1/2
= 62.8)
Minor, Irradiated:
Volatile organics
E-clethodim
Ketone of
clethodim imine
Clethodim imine
sulfoxide
Clethodim
sulfoxide
Clethodim imine
Z-Clethodim
Major:
Clethodim imine,
Clethodim
sulfoxide,
clethodim sulfone
and clethodim
oxazole, CO2
Minor:
Volatile organics,
clethodim imine
sulfoxide,
clethodim imine
sulfone,
clethodim oxazole
sulfoxide and
Proposed Re-evaluation Decision - PRVD2016-11
Page 78
2475150
1234275
Clethodim is nonpersistent.
Biotransformation
in aerobic watersediment systems
is a route of
dissipation for
clethodim.
Appendix VIII
clethodim
Biotransformation in
anaerobic
watersediment
systems
Pond water: loamy silt
sediment at 20oC
Whole system DT50:
23.6 d; DT90: 78.5 d
Clethodim
sulfoxide
Whole system DT50:
49.1 d; DT90: 163 d
Clethodim
imine sulfoxide
Whole system DT50:
50.8 d; DT90: 169 d
Clethodim
imine
DT50 could not be
calculated as
concentrations increased
until study termination.
Clethodim
slough water: sandy clay
loam sediment
dark system at 25°C
Whole system DT50: 108
d; DT90: 657 d
DFOP(slow t1/2 = 237)
dark system at 5°C
Whole system DT50: 530
d; DT90: 1760 d
clethodim oxazole
sulfone.
Major:
Water:
Clethodim
sulfoxide
Sediment:
Clethodim imine,
Clethodim imine
sulfoxide, CO2
Minor:
Volatile organics,
clethodim
oxazole,
clethodim imine
sulfone and
clethodim sulfone
Major:
Clethodim imine
and clethodim
sulfoxide
combined.
DT50 could not be
calculated as
concentrations
increased until
study termination.
2416280
clethodim,
clethodim
sulfoxide and
clethodim imine
sulfoxide are
moderately
persistent
Clethodim imine
may be persistent
Clethodim is
moderately
persistent
1234276
Biotransformation
in anaerobic
water-sediment
systems is a route
of dissipation for
clethodim.
Minor:
Aqueous
Clethodim
oxazole sulfoxide,
clethodim oxazole
sulfone
sediment
clethodim imine
sulfoxide,
clethodim
sulfone,
clethodim imine
sulfone,
clethodim oxazole
CO2
Field studies
Aquatic field
No aquatic field dissipation study with clethodim was submitted, and data on the aquatic field
dissipation
disspiation of clethodim are not required.
Bioconcentration/bioaccumulation
Bioconcentra- [allyl] and
Clethodim
Did not
1227461
Whole fish steady state
tion in bluegill [ring]-14C
sulfoxide
bioconcentrate in
BCF: 2.1 for allyl] and
sunfish
large amounts in
clethodim at
[ring]-14C clethodim
fish under the test
0.05 mg/L
conditions of the
(nominal
study.
concentration)
Proposed Re-evaluation Decision - PRVD2016-11
Page 79
Appendix VIII
Table 4 Toxicity of clethodim and transformation products to Non-Target terrestrial
Species
Organism
Exposure
Test substance
Endpoint value
Degree of
toxicity1
PMRA#
Invertebrates
Earthworm,
Eisenia foetida
14-d Acute
Clethodim Agan
Technical
(95.8%)
Clethodim
sulfoxide
Select
(clethodim 240
EC) 28.4%.
Clethodim 240
CE (240 g/L)
LC50: 1767 mg a.i./kg
soil
No
classification
1074747
LC50: >1000 mg/kg
soil
LC50: 454 mg/kg soil
= 129 mg a.i/kg soil
No
classification
No
classification
2416283
LC50: 353.55 mg/kg
soil
= 84.8 mg a.i/kg soil
LD50: 313 µg a.i./bee
No
classification
1074729
Relatively nontoxic
1074749
14-d Acute
14-d Acute
14-d Acute
Honeybee, Apis
mellifera
48-h Oral
72-h Oral
48-h Oral
48-h Contact
Parasitoid wasp,
Aphidius
rhopalosiphi
48h-Contact,
Predatory mite,
Typhlodromus pyri
14-d Contact,
extended
laboratory
Predatory mite,
14-d Contact,
Clethodim Agan
technical
(95.8%)
Select 240 EC
240g clethodim/L
Select 240 EC
240g clethodim/L
Mixture of Select
+ Para sommer
256 g clethodim/L
Clethodim Agan
technical
(95.8%)
Clethodim
87.9%a.i.
Select 2.0 EC
25.6% .
Select 240 EC
240g clethodim/L
Mixture of Select
+ Para sommer
256 g clethodim/L
1:2 (v/v)
mixtures of
Select (25%
clethodim/L) and
Para Sommer
(75% Paraffin
oil)
1:2 (v/v)
mixtures of
Select (25%
clethodim/L) and
Para Sommer
(75% Paraffin
oil)
1:2 (v/v)
LD50: >51 µg a.i./bee
LD50: >43 µg a.i./bee
LD50: 55 µg a.i./bee
Relatively nontoxic
Relatively nontoxic
Relatively nontoxic
1234271
2416283
LD50: 37.29 µg
a.i./bee
Relatively nontoxic
1074748
LD50: >100 µg a.i./bee
Relatively nontoxic
Relatively nontoxic
Relatively nontoxic
Relatively nontoxic
1227462
LD50:> 33 µg a.i./bee
LD50:> 51 µg a.i./bee
LD50: 68 µg a.i./bee
LR50: >240 g a.i./ha
No
classification
LR50: <9.6 g a.i/ha
No
classification
LR50: 3.6 g a.i/ha
No
Proposed Re-evaluation Decision - PRVD2016-11
Page 80
2416283
2416283
Appendix VIII
Organism
Exposure
Test substance
Typhlodromus pyri
extended
laboratory
including 7 days
fecundity
assessment
Poecilus cupreus
14-d laboratory
(sand)
mixtures of
Select (25%
clethodim/L) and
Para Sommer
(75% Paraffin
oil)
1:2 (v/v)
mixtures of
Select (25%
clethodim/L) and
Para Sommer
(75% Paraffin
oil)
Select 240
Aleochara
bilineata
Chrysoperla
carnea
Birds
Northern bobwhite
quail,
Colinus
virginianus
Mallard duck,
Anas
platyrhynchos
14-d laboratory
(sand)
14-d laboratory
(sand)
Endpoint value
Degree of
toxicity1
classification
LR50: >256 g a.i/ha
No
classification
LR50: >221 g a.i/ha
No
classification
No
classification
PMRA#
Select 240
LR50: >259 g a.i/ha
6 weeks
extended
laboratory
exposure to dry
residues in
conjunction with
esterified rape
seed oil (1.0
L/ha) on
labortaory
treated apple
leaves
Select 240
LR50: >384 g a.i/ha
No
classification
Acute
Clethodim (82%)
Practically nontoxic
1229456
5-d Dietary
Clethodim (82%)
Practically nontoxic
1229457
22-w
Reproduction
Clethodim
(83.3%)
5-d Dietary
Clethodim (82%)
19-w
Reproduction
Clethodim
(83.3%)
LD50: >2000 mg
a.i./kg bw
LD50: >1640 mg
a.i./kg bw (corrected
for purity)
LC50: >6000 mg
a.i./kg diet;
(LD50: 637 mg a.i./kg
bw/d)
NOEC: 188 mg a.i./kg
diet (reduced embryo
viability)
(NOEL: 19.96
mg a.i./kg bw/d)
LC50: >6000 mg
a.i./kg diet
(LD50: >339.4 mg
a.i./kg bw/d)
NOEC: 833 mg a.i./kg
diet (highest
concentration tested)
(NOEL: 47.12 mg
a.i./kg bw/d)
Proposed Re-evaluation Decision - PRVD2016-11
Page 81
No
classification
1229460;
1229461
Practically nontoxic
1229459
No
classification
1229462;
1229463
Appendix VIII
Organism
Exposure
Mammals
Mice
Test substance
Clethodim
RE-45601
(83.3% purity)
Endpoint value
LD50 (M) = 2570
mg/kg bw
Degree of
toxicity1
PMRA#
Practically nontoxic
12298601
Slightly toxic
1229862;
1232654
Slightly toxic
1227466
Slightly toxic
1227466
LD50 (♀) = 2430 mg/kg
bw
Signs: hypoactivity,
rough coat, hunched
posture, ataxia, urine
stains, tremors,
salivation
Necropsy: in mice that
died: slightly dark-red
lungs, compound like
material in the GI tract
(no abnormalities noted
in surviving mice)
Rats
Clethodim
RE-45601
LD50 (M) = 1630mg/kg
bw
LD50 (♀) = 1360
mg/kg bw
Signs: Day 1: salivation,
9motor activity, clonic
convulsions, tremoring
and/or unsteady gait,
hyperactivity, collapse.
Day 2-6 in survivors:
9food consumption,
yellow anogenital
staining.
Acute
Necropsy: dark
gelatinous material
beneath the meninges,
mottled/reddened lungs,
foam in the trachea, very
small lesions of gliosis
in a single spinal nerve
in lower lumbar area in
2 ♀s at 1.45 g/kg bw.
Rats
Imine sulfone
RE-47719
Rats
5-OH sulfone
RE-51228
Vs.
Clethodim
RE-45601
LD50 (♀) > 1400 mg/kg
bw
5-OH sulfone
LD50 (♀) > 1400 mg/kg
bw
(no mortality or clinical
signs of toxicity, ↑bw of
63 g during the 14 day
post-treatment period,
no gross tissue
Proposed Re-evaluation Decision - PRVD2016-11
Page 82
Appendix VIII
Organism
Exposure
Test substance
Endpoint value
Degree of
toxicity1
PMRA#
No
classification
122738291,
1227399,
1234281
abnormalities)
Clethodim
Severe signs of toxicty
(salivation, decreased
motor activity, collapse,
hyperactivity, tremors,
9food consumption,
diarrhoea, dehydration
and nasal, ocular, oral
and ano-genital
discharges), all animals
died within 3 days, 9bw
day 0-2, necropsy
showed red discolored
lungs, blood pooled
beneath the cranial
meninges and black
discolored spleen,
gastric mucosa, intestine
and caecum
Rats
2-generation
Reproduction
Clethodim
Parental
NOAEL: 28 mg /kg
bw/d (body weight,
food consumption
(occassional)
Offspring
NOAEL: ≥148 mg /kg
bw/d (pup body
weight) [F1a→F2a
generation, slight during
lactation (0, -4.4%, 6.8%, -2.5%, -5.9% at
day 0, 4, 7, 14, 21), but
not stat. sig.]
Reproduction
NOAEL: ≥148 mg/kg
bw/d (No treatment
related effects observed
in male and female
mating, fertility and
pregnancy rates; slight
8incidence still born
pups) (F0 -> F1
generation)*
*Number of stillborn
(%): F0->F1a generation
– 2 (0.7), 5(1.6), 5(1.7),
7(2.5), 14(3.8)
Proposed Re-evaluation Decision - PRVD2016-11
Page 83
Appendix VIII
Organism
Vascular plants
Monocot crop
species (onion, oat
and corn); dicot
crop species (rape,
carrot and
redclover)
Dicot crop species
(soybean, lettuce,
carrot, tomato,
cucumber and
cabbage)
Monocot crop
species (onion,
ryegrass, oat and
corn)
Exposure
Test substance
Endpoint value
Degree of
toxicity1
PMRA#
Tier 1 post
emergence
Select 2 EC-H
(26.4%
clethodim) +
Para Sommer
(75% parafin
oil) 1:2 v/v
Most sensitive
monocot specie was
corn
ER50: 8 g a.i./ha
NOEC: 4 g a.i./ha
(Plant survival)
No
classification
2416283
21& 28-d
Seedling
emergence
Select
(formulation
containing
82.4%
clethodim)
Select
(formulation
containing
82.4%
clethodim)
ER25: >280 g a.i./ha
NOEC: 280 g a.i./ha
(highest dose tested)
No
classification
1233499
2452948
USEPA and study
author’s most sensitive
species: oats
Study author’s
endpoints:
ER25: 4.5 g a.i./ha
ER50: 53.8 g a.i./ha
NOEC: 7.1 g a.i./ha
(Plant hieght)
No
classification
1233500
2452954
2452948
Tier II
21-d Seedling
emergence
USEPA’s endpoints:
ER25: 8.5 g a.i./ha
ER05 (NOEC): 0.45 g
a.i./ha (Plant hieght)
Oat (Avena sativa)
Perennial ryegrass
(Lolium perenne)
Corn (Zea mays)
Onion (Allium
cepa)
Dicot crop species
(soybean, lettuce,
carrot, tomato,
cucumber and
cabbage)
21& 28-d
vegetative vigour
Select
Select
ER50: 54 g a.i./ha
ER50: 67 g a.i./ha
Select
Select
ER50: 25 g a.i./ha
ER50: > 280 g a.i/ha
Select
(formulation
containing
82.4%
clethodim)
ER25: >280 g a.i./ha
NOEC: 280 g a.i./ha
(highest dose tested)
Proposed Re-evaluation Decision - PRVD2016-11
Page 84
2416284
No
classification
1233497
2452948
Appendix VIII
Organism
Exposure
Test substance
Endpoint value
Monocot crop
species (onion,
ryegrass, oat and
corn)
Tier II
21-d Vegetative
vigour
Select
(formulation
containing
82.4%
clethodim)
USEPA’s most
sensitive species:
ryegrass
Degree of
toxicity1
No
classification
PMRA#
1233498
2452959
2452948
2416284
Study author’s
endpoints:
ER25: 3.4 g a.i./ha
ER50: 6.7 g a.i./ha
NOEC: 3.4 g a.i./ha
(Plant dryweight)
USEPA’s endpoints
ER25: 3.4 g a.i./ha
ER05 (NOEC): 2.2 g
a.i./ha (Plant
dryweight)
EAD’s endpoints:
Most sensitive species:
ryegrass
ER25: 6.95 g a.i./ha
(plant height)
ER50: 6.7 g a.i./ha
Ryegrass
Clethodim
No
2416284
(L.perenne)
classification
ER50: 3.4 g a.i./ha
Cockspurr grass
Clethodim
(E. crus-galli)
ER50: 20 g a.i./ha
Oat (Avena sativa)
Select
ER50: >280 g a.i./ha
Soybean
Select
(Glycine max)
ER50: 13 g a.i./ha
Corn (Zea mays)
Select
ER50: > 280 g a.i/ha
Onion (Allium
Select
cepa)
ER50: > 280 g a.i/ha
Lettuce
Select
(Lactuca sativa)
ER50: > 280 g a.i/ha
Carrot
Select
(Daucus carota)
ER50: > 280 g a.i/ha
Tomato
Select
(Lycopersicon
HC5: 2.39 g a.i/ha
esculentum)
1
Atkins et al. (1981) for bees and USEPA classification for others, where applicable
The avian dietary and reproduction endpoints were converted from concentration to daily dose using the
following equation: Daily Dose = Concentration in food × (FIR/BW)
where: Concentration in food: Toxicity endpoint (for example, LC50 or NOEC), in mg a.i./kg diet
FIR: Food ingestion rate (equivalent to food consumption), in g diet/day
BW: Body weight, in g
Bold indicates most sensitive endpoints used in risk assessment
Proposed Re-evaluation Decision - PRVD2016-11
Page 85
Appendix VIII
Table 5 Screening level and refined risk assessment of clethodim to beneficial arthropods
Organism
Exposure
Endpoint value
EEC
RQ
(EEC/endp
oint)
LOC
exceede
d?
(LOC =
1 unless
otherwi
se
stated)
Implications for
further
refinements
Aphidius
rhopalosiphi
(Parasitic
wasp)
48 h, acute
Laboratory test,
1:2 (v/v)
mixtures of
Select (25%
clethodim/L)
and Para
Sommer (75%
Paraffin oil)
Exposure to residues on sprayed
plants
LR50 : >240 g a.i./ha
In field 91.2 g
a.i./ha
<0.38
No
No refinement
required. No
unacceptable risk
to parasitic wasps
both on and off
field.
Typhlodromu
s pyri
(Predatory
mite)
14 d Extended
laboratory test,
leaf disks 1:2
(v/v) mixtures
of Select (25%
clethodim/L)
and Para
Sommer (75%
Paraffin oil)
LR50 3.6 g a.i./ha 73% corrected
mortality) (highest rate tested)
In field 91.2 g
a.i./ha
25.3
Yes
(LOC
>1 for
extende
d
laborato
ry test)
off field
5.83
Yes
(LOC
>1 for
extende
d
laborato
ry test
Arthropods
(aerial
application
23% of rate)
– 20.976 g
a.i./ha
1.52
Yes
(LOC
>1 for
extende
d
laborato
ry test
In field –
45.6 g
a.i./ha
12.7
Yes
(LOC
>1 for
extende
d
laborato
ry test)
off field
2.91
Yes
(LOC
>1 for
extende
d
laborato
ry test
off field
(aerial
application
6% of rate)
– 5.47 g
a.i./ha
14 d Extended
laboratory test,
leaf disks 1:2
(v/v) mixtures
of Select (25%
clethodim/L)
and Para
Sommer (75%
Paraffin oil)
LR50 3.6 g a.i./ha 73% corrected
mortality) (highest rate tested)
(aerial
application
23% of rate)
– 10.49 g
a.i./ha
Proposed Re-evaluation Decision - PRVD2016-11
Page 86
Refinement
required. Risks to
predatory mites
both on and off
field at the highest
and lowest
application rates.
No field studies
available for
refinement.
Appendix VIII
Organism
Exposure
Endpoint value
EEC
RQ
(EEC/endp
oint)
LOC
exceede
d?
(LOC =
1 unless
otherwi
se
stated)
off field
0.76
No
Implications for
further
refinements
(aerial
application
6% of rate)
– 2.74 g
a.i./ha
Aleochara
bilineata
14-d laboratory
(sand)
Select 240
LR50 >259 g a.i./ha (0.115 mg/kg
soil)
In field –
91.2 g a.i/ha
(0.041
mg/kg soil )
<0.36
No
No refinement
required. No
unacceptable risk
to ladybird beetle
both on and off
field
Chrysoperla
carnea (green
lacewing)
6 weeks
extended
laboratory
exposure to dry
residues in
conjunction
with esterified
rape seed oil
(1.0 L/ha) on
labortaory
treated apple
leaves
Select 240
LR50 >384 g a.i./ha
In field –
91.2 g
a.i./ha
<0.24
No
No refinement
required. No
unacceptable risk
to green lacewing
both on and off
field.
Poecilus
cupreus
14-d laboratory
(sand)
1:2 (v/v)
mixtures of
Select (25%
clethodim/L)
and Para
Sommer (75%
Paraffin oil)
LR50 >256 g a.i./ha
In field –
91.2 g a.i/ha
(0.041
mg/kg soil )
<0.42
No
No refinement
required.
14-d laboratory
(sand)
Select 240
LR50 >221 g a.i./ha .
In field –
91.2 g a.i/ha
(0.041
mg/kg soil )
<0.37
No
No refinement
required.
Proposed Re-evaluation Decision - PRVD2016-11
Page 87
Appendix VIII
Table 6 Screening level risk assessment of clethodim to earthworms, bees and terrestrial
vascular plants
Exposure
(Endpoint):
Substance
Organism
RQ
Level of
Concern
Exceeded?
0.0001
No
0.0006
No
0.041 mg a.i./kg
soil1
0.0010
No
>500 mg a.i./kg
soil
0.042 mg a.i./kg
soil1
<0.0001
No
37.29 μg
a.i./bee
2.64 μg a.i./bee1
0.071
No
>33 μg a.i./bee
2.64 μg a.i./bee1
<0.08
No
0.0007
No
<0.005
No
Endpoint
Value
EEC
883.5 mg
a.i./kg soil
64.5 mg a.i./kg
soil
0.041 mg a.i./kg
soil1
0.041 mg a.i./kg
soil1
42.45 mg
a.i./kg soil
Invertebrates
Earthworm
(Eisenia
foetida)
Bees (Apis
mellifera)
Acute Mortality (14-d
LC50/2): Clethodim
Acute Mortality (14-d
LC50/2): Select
Acute Mortality (14-d
LC50/2):
Clethodim 240
Acute Mortality (14-d
LC50/2):
Clethodim sulfoxide
Acute Contact (48-h
LC50): Clethodim
Acute Contact (48-h
LD50): Select 2.0
Acute Oral (48-h
LD50): clethodim
Acute Oral (48-h
LD50): Select 240
313 μg a.i./bee
>43 μg a.i./bee
0.219 μg
a.i./bee2
0.219 μg
a.i./bee2
Vascular plants
Yes (LOC >1 at
Ryegrass,
2.39 g a.i./ha
91.2 g a.i./ha
the screening
35.16
Cockspur grass,
Species Sensitivity
level)
soybean, corn,
Distribution (HC5):
onion, lettuce,
Yes (LOC >1 at
Vegetative vigour
carrot and
2.39 g a.i./ha
45.6 g a.i./ha
the screening
19.08
Tomato
level)
1
Endpoint derived according to Koch and Weißer (1997), whereby the proposed upper-bound residue value for
estimating exposure to bees is based on a maximum residue value: 0.0912 kg a.i./ha × 2.4 µg a.i./bee per kg/ha =
0.219 µg a.i./bee.
2
Endpoint based on consumption rates primarily derived from Rortais et al. (2005) and Crailsheim et al. (1992 and
1993), whereby the oral exposure estimate for adult bees is calculated by multiplying the direct single rate by 29 µg
a.i./bee per kg/ha: 0.0912 kg a.i./ha × 29 µg a.i./bee per kg/ha = 2.645 µg a.i./bee.
Table 7 Estimated Environmental Concentrations (EEC) in vegetation and insects
Food item
Short range grass
Leaves and leafy crops
Long grass
Forage crops
Small insects
Pods with seeds
Large insects
EEC (mg a.i./kg fw) a
Maximum
Mean
Residues
Residues
20
7
11
4
9
3
11
4
5
3
1.2
0.6
1.2
0.6
Fresh / dry
weight ratios
3.3 b
11 b
4.4 b
5.4 b
3.8 c
3.9 c
3.8 c
EEC (mg a.i./kg dw)
Maximum
Mean
Residues
Residues
64
23
121
40
39
13
60
20
18
10
5
2.2
5
2.2
Proposed Re-evaluation Decision - PRVD2016-11
Page 88
Appendix VIII
Grain and seeds
Fruit
1.2
1.2
a
3.8 c
7.6c
0.6
0.6
5
9
2.2
4.3
Based on correlations reported in Hoerger and Kenaga (1972) and Kenaga (1973) and modified by Fletcher (1994)
Fresh / dry weight ratios from Harris (1975)
c
Fresh / dry weight ratios from Spector (1956)
b
Table 8 Further characterization of risk to Terrestrial Vascular Plants
Aerial Application
(23% spray drift)
Off Field
On-field
Species
Endpoint
EEC
(g a.i./ha)
RQ
EEC
(g a.i./ha)
Ryegrass,
91.2
20.98
Cockspur
38.16
Species
grass,
Sensitivity
soybean,
Distribution
corn, onion,
(HC5):
lettuce,
45.6
10.5
19.08
2.39 g a.i./ha
carrot and
Tomato
Bold cells indicate that the level of concern is exceeded (LOC = 1).
Ground Application
(6% spray drift)
Off-field
RQ
EEC
(g a.i./ha)
RQ
8.8
5.472
2.3
4.4
2.736
1.14
Table 9 Screening level risk assessment of clethodim to birds and mammals
Toxicity
(mg ai/kg
bw/d)
Feeding Guild (food item)
EDE (mg
ai/kg bw/d)
RQ
Small Bird (0.02 kg)
Acute
164
Insectivore (insects)
4.60
0.028
Reproduction
19.96
Insectivore (insects)
4.60
0.23
Medium Sized Bird (0.1 kg)
Acute
164
Insectivore (insects)
3.59
0.022
Reproduction
19.96
Insectivore (insects)
3.59
0.18
Large Sized Bird (1 kg)
Acute
164
Herbivore (short grass)
3.74
0.023
Reproduction
19.96
Herbivore (short grass)
3.74
0.19
Small Mammal (0.015 kg)
Acute
136
Insectivore (insects)
2.64
0.019
Reproduction
28
Insectivore (insects)
2.64
0.09
Medium Sized Mammal (0.035 kg)
Acute
136
Herbivore (short grass)
8.28
0.061
Reproduction
28
Herbivore (short grass)
8.28
0.30
Large Sized Mammal (1 kg)
Acute
136
Herbivore (short grass)
4.42
0.033
Reproduction
28
Herbivore (short grass)
4.42
0.16
a
Food Ingestion Rates (Nagy, 1987). For generic birds with body weight less than or equal to 200
g, the “passerine” equation was used; for generic birds with body weight greater than 200 g, the
Proposed Re-evaluation Decision - PRVD2016-11
Page 89
Appendix VIII
Toxicity
(mg ai/kg
bw/d)
Feeding Guild (food item)
EDE (mg
ai/kg bw/d)
RQ
“all birds” equation was used:
Passerine Equation (body weight < or =200 g): FIR (g dry weight/day) = 0.398(BW in g) 0.850
All birds Equation (body weight > 200 g): FIR (g dry weight/day) = 0.648(BW in g) 0.651. For
mammals, the “all mammals” equation was used: FIR (g dry weight/day) = 0.235(BW in g) 0.822
b
EDE = Estimated dietary exposure; is calculated using the following formula: (FIR/BW) × EEC.
At the screening level, food items representing the most conservative EEC for each size guild are
used. Shaded cells indicate that the level of concern is exceeded (LOC = 1).
Table 10 Toxicity of clethodim and end-use products to Non-Target aquatic Species
Organism
Exposure
Test substance
Endpoint value
Degree of
toxicity1
PMRA#
Freshwater species
Daphnia magna
48-h Acute
Clethodim
Agan TGAI
(95.8% purity)
Select 240 EC
Formulation
(240 g/L)
EC50: 101.64 mg
a.i./L
Practically nontoxic
1074750
EC50: 22.06 mg
form./L
Equivalent to
EC50: 5.3 mg
a.i../L
EC50: 20.2. mg
form./L
Equivalent to
EC50: 5.1 mg
a.i../L
EC50: 21 mg
form./L
Equivalent to
EC50: 5.2 mg
a.i../L
NOEC: 49 mg
a.i./L (parental
survival and
reproduction)
NOEC: 0.00084
mg a.i./L
NOEC: 0.51 mg
a.i./L (nominal
concentration)
Moderately
toxic
1074722
Moderately
toxic
2416283/
2416285
Moderately
toxic
2416283
No
classification
2416283
No
classification
No
classification
2416284
NOEC: 0.94 mg
a.i./L
LOAEC: 3.0 mg
a.i./L
No
classification
2452948
48-h Acute
48-h Acute
Select 2EC
formulation
(25.6%)
48-h Acute
Select 240 EC
formulation
(240 g
clethodim/L)
21-d Chronic
clethodim
(92.4% purity)
21-d Chronic
Select(25.6% )
+ oily adjuvant
TM-20016
(240 g/L
clethodim
formulation
without oily
adjuvant)
Clethodim
Agan TGAI
(95.8% purity)
21-d Chronic
21-d Chronic
Proposed Re-evaluation Decision - PRVD2016-11
Page 90
Appendix VIII
Organism
Exposure
Test substance
Endpoint value
Sediment dwelling
invertebrate,
Chironomus riparius
28-d Chronic,
spiked water
Clethodim
imine
(chemical
purity 97.6%)
Rainbow trout,
Oncorhynchus mykiss
96-h Acute
Clethodim
technical (RE45601)
(83.3%)
Clethodim
technical
(95.4%)
Select 240 EC
(25.5% w/w
clethodim)
Clethodim
sulfoxide
NOEC: 10 mg
a.i./L (total
emergence)
nominal
concentration
LC50: 24.4 mg
a.i./L
96-h Acute
96-h Acute
96-h Acute
21-d prolonged
toxicity study
Clethodim
(95.2%)
21-d prolonged
toxicity study
Select(25.6% )
+ oily adjuvant
21-d prolonged
toxicity study
TM-20016
(240 g/L
clethodim
formulation
without oily
adjuvant
Clethodim
technical (RE45601)
(83.3%)
Clethodim
Agan technical
(97.5%)
Clethodim
240 g/L CE
formulation
Clethodim
technical
(95.4%)
Clethodim
technical
(95.7%)
Bluegill sunfish
Lepomis macrochirus
96-h Acute
Zebra fish Danio rerio
96-h Acute
96-h Acute
Fathead minnow,
Pimephales promelas
96-h Acute
Early-life stage
Green algae,
Pseudokirchneriella
subcapitata
120-h Acute
Clethodim
(83.3%)
Degree of
toxicity1
No
classification
PMRA#
2416283
Slightly toxic
1227450
LC50: >110 mg
a.i./L
Practically nontoxic
2416285
LC50: 13 mg
formulation./L
(3.4 mg a.i./L)
LC50: >100 mg
a.i./L (mortality,
nominal
concentrations)
NOEC: 3.9 mg/L
(mean measured
concentration)
NOEC: 0.29
mg/L (mean
measured
concentration)
NOEC: 1.1 mg/L
(nominal
concentrations)
Moderately
toxic
2416283
Practically nontoxic
2416284
No
classification
2416283
No
classification
2416284
LC50: >33 mg
a.i./L
Slightly toxic
1229464
LC50: 134.2 mg/L
Practically nontoxic
1074751
LC50: 24 mg
formulation./L
(5.8 mg a.i./L)
LC50: 110 mg
a.i./L
Moderately
toxic
1074730
Practically nontoxic
2416285
NOEC: 0.010 mg
a.i./L (survival)
No
classification
2452948
No
classification
1234998:
1234999
LOEC: 0.031 mg
a.i./L
EC50: >11.4 mg
a.i./L (measured
concentration)
Proposed Re-evaluation Decision - PRVD2016-11
Page 91
No
classification
Appendix VIII
Organism
Exposure
Test substance
Endpoint value
72-h Acute
Clethodim
Agan
Technical
(97.5%)
Clethodim
240g/L CE
formulation
ECb50: 3.87 mg
/L (biomass)
72-h Acute
Green alga,
Scenedesmus
subspicatus
72-h Acute
Select 2.0 EC
(25.6%)
72-h Acute
Clethodim
(92.4%)
72-h Acute
Select 2.0 EC
(26..6%)
formulation
containingPara
Sommer1:2v/v)
Clethodim
sulfoxide
(99.4%)
Clethodim EC
(12%)
Degree of
toxicity1
No
classification
PMRA#
1074757
EC50: 33.55 mg
clethodim 240g/L
(approximately
8.1 mg a.i./L of
each active
ingredient) (cell
density/biomass)
Most sensitive
endpoint:
EC50: 4.6 mg
a.i./L (biomass)
Most sensitive
endpoint:
EC50: 36 mg/L
(biomass)
Most sensitive
endpoint:
EC50: 1.5 mg
a.i./L (biomass)
No
classification
1074732
No
classification
2416283
No
classification
2416283
No
classification
2416283
EC50: >100 mg/L
(biomass)
No
classification
2416283
EC50: 4.6 mg
a.i./L (growth
rate)
No
classification
2416285
Green alga,
Desmodesmus
subspicatus
Green alga, Chlorella
vulgaris
72-h Acute
Green alga,
Raphidocelis
subcapitata
96-h- Acute
Clethodim EC
(12%)
EC50: 2.7 mg
a.i./L (growth
rate)
No
classification
2416285
Blue-green algae,
Anabaena flos-aquae
72-h Acute
Select 2.0 EC
(25.6%.)
Most sensitive
endpoint:
EC50: 3.2 mg
a.i./L (growth
rate)
No
classification
2416283
Diatom, Navicula
pelliculosa
96-h Acute
Clethodim
(94.8%)
EC50: 36 mg/L
(biomass)
EC50: 56 mg/L
(growth rate)
No
classification
2416283
72-h Acute
Select 2.0 EC
(25.6%.)
Most sensitive
endpoint:
EC50: 5.4 mg
a.i./L (biomass)
No
classification
2416283
96-h- Acute
Proposed Re-evaluation Decision - PRVD2016-11
Page 92
Appendix VIII
Organism
Exposure
Test substance
Endpoint value
Monocot vascular
plant, duckweed,
Lemna gibba
7-d Semi static
Clethodim
Technical
(94.2%)
14-d Static
RE-45601
technical
(82.4%.)
14-d Static
Clethodim
technical
(91.1%.)
14-d Semi-Static
Select 2.0 EC
(25.6%.)
Most sensitive
endpoint:
EC50: 5.8 mg
a.i./L (frond area)
Most sensitive
endpoint:
EC50:1.34 mg
a.i../L (frond
counts)
Most sensitive
endpoint:
EC50: > 4. 8 mg
a.i./L (growth
rate)
Most sensitive
endpoint:
EC50: 42.5. mg
a.i./L (frond
counts)
Marine/estuarine species
Eastern Oyster,
96-h Acute
Crassostrea virginica
Saltwater mysids
Americamysis bahia
96-h Acute
Sheepshead minnow,
Cyprinodon variegatus
chronic
clethodim
Technical
(95.4%.)
clethodim
Technical
(95.4%.)
clethodim
Technical
(95.4%.)
Degree of
toxicity1
No
classification
PMRA#
1371484
No
classification
2416283;
2452948
No
classification
2416283
No
classification
2416283;
2452948
96-hr EC50 = 5.3
mg a.i./L
moderately
toxic
96-hr EC50 = 33
mg a.i./L
slightly toxic
NOEC: 4.2 mg
a.i./L
No
classification
2452948
2452961
2452951
2452949
2452948
2452961
2452950
2452948
2452961
2416283
No
Most sensitive
classification
endpoint:
EC50: 5.3 mg
Select 2.0 EC a.i./L (biomass)
(25.6%)
EPA
Most sensitive
No
2416285
120-h Acute
endpoint:
classification
EC50: 8.6 mg/L
(biomass)
1
USEPA classification, where applicable; Bold indicate most sensitive endpoints used in risk assessment.
TGAI = technical grade active ingredient
Marine diatom,
Skeletonema costatum
EFSA
72-h Acute
Table 11 Screening level risk assessment of clethodim and transformation products for
aquatic organisms
Organism
Exposure
(Endpoint):
Substance
Endpoint
Value
(mg a.i./L)
EEC
RQ
Level of
Concern
Exceeded?
50.82
0.0114
0.0002
No
2.55
0.0114
0.0045
No
0.94
0.0114
0.0121
No
Freshwater species
Daphnia magna
Acute (48-h EC50/2):
Clethodim
Acute (48-h EC50/2):
Select 2 EC (25.6%)
Chronic (21-day
NOEC): Clethodim
Proposed Re-evaluation Decision - PRVD2016-11
Page 93
Appendix VIII
Benthic
Invertebrate
(chironomid)
Rainbow Trout
Fathead Minnow
Amphibians (most
sensitive fish)
Freshwater alga
(green Pseudokirchneriella
subcapitata)
Scenedesmus
subspicatus
Anabaena flosaquae
Desmodesmus
subspicatus
Vascular plant
(duckweed - Lemna
gibba)
Marine Species
Saltwater mysids
Americamysis
bahia
Eastern Oyster,
Crassostrea
virginica
Marine algae
(diatom(Skeletonema
costatum)
Chronic (21-day
NOEC): Select +
Oily adjuvant
Chronic (28-day
NOEC): Clethodim
imine
Acute (96-h
LC50/10): Clethodim
Acute (96-h
LC50/10): Select 240
EC
21-d prolonged
NOEC: Select 25.6%
Acute (96-h
LC50/10): Clethodim
sulfoxide
Chronic (32-d early life cycle NOEC):
Clethodim
Acute (96-h
LC50/10): Select 240
EC
Chronic (early-life
cycle NOEC):
clethodim
0.00084
0.0114
13.57
Yes
10
0.009
0.0009
No
2.44
0.0114
0.005
No
0.34
0.0114
0.034
No
0.29
0.0114
0.039
No
>10
0.012
<0.001
No
0.01
0.0114
1.14
Yes
0.34
0.061
0.18
No
0.01
0.061
6.10
Yes
1.94
0.0114
0.006
No
0.75
0.0114
0.015
No
1.6
0.0114
0.007
No
>10
0.012
<0.0002
No
2.9
0.0114
0.004
No
0.67
0.0114
0.017
No
21.25
0.0114
0.0005
No
Acute (96-h EC50/2):
Clethodim
16.5
0.0114
0.0007
No
Acute (96-h EC50/2):
Clethodim
2.65
0.0114
0.004
No
Acute (72-h EC50/2):
Select 25.6%
2.65
0.0114
0.004
No
Acute (72-h EC50/2):
Clethodim
Acute (72-h EC50/2):
Select + Para
Sommer
Acute (72-h EC50/2):
Select 2.0 EC
Acute (72-h EC50/2):
Clethhodim sulfoxide
Acute (7-day
EC50/2): Clethodim
Acute (14-day
EC50/2): Clethodim
Acute (14-day
EC50/2): Select 2.0
EC
Proposed Re-evaluation Decision - PRVD2016-11
Page 94
Appendix VIII
Sheepshead
minnow,
Cyprinodon
variegatus
Chronic (34-d earlylife cycle NOEC):
Clethodim
4.2
0.0114
0.003
No
Table 12 Risk Quotients for aquatic organisms determined for drift of clethodim
Organism
Exposure
Endpoint value
Refined EEC
RQ
Freshwater
invertebrate
(Daphnia
magna)
Freshwater fish –
rainbow trout
Watersediment
system
NOEC = 0.00084
mg a.i./L
3.1
0.8
Not exceeded
Watersediment
system
NOEC = 0.01 mg
a.i./L
Aerial appl. (23% drift):
0.0026 mg a.i./L
Ground appl. (6% drift): 0.0007
mg a.i./L
Aerial appl. (23% drift):
0.0026 mg a.i./L
Level of
Concern
Exceeded
0.3
Not exceeded
Ground appl. (6% drift): 0.0007
mg a.i./L
0.1
Not exceeded
Watersediment
system
NOEC = 0.01 mg
a.i./L
Aerial appl. (23% drift): 0.01403
mg a.i./L
Ground appl. (6% drift): 0.0037
mg a.i./L
1.4
Exceeded
(marginally)
Not exceeded
Amphibia
(Xenopus laevis)
0.4
Level of concern exceeded for values in bold (RQ > 1)
Table 13 Risk Quotients for Aquatic Organisms Determined for Runoff of clethodim in
Water Bodies 80 or 15 cm deep
Organism (exposure)
Freshwater Fish
(Chronic risk)
Endpoint value
NOEC: 0.01 mg
a.i./L
EEC concentrations (time-frame,
water body)
90 day, 80 cm water body: 0.0014mg
a.i./L
Amphibians (Chronic
NOEC: 0.01 mg
90 day, 15 cm water body: 0.0043mg
risk)
a.i./L
a.i./L
Level of concern exceeded for values in bold (RQ > 1)
Proposed Re-evaluation Decision - PRVD2016-11
Page 95
RQ
Level of
Concern
0.14
Not exceeded
0.43
Not exceeded
Appendix VIII
Proposed Re-evaluation Decision - PRVD2016-11
Page 96
Appendix IX
Appendix IX
Proposed Label Amendments for Products
Containing Clethodim
The label amendments presented below are proposed for technical and end-use products, as
applicable. These label amendments do not include all label requirements for individual end-use
products, such as first aid statements, disposal statements, precautionary statements and
supplementary protective equipment. Information on labels of currently registered products
should not be removed unless it contradicts the label statements below.
Use Precautions:
Replace:
 “When handling the concentrate, mixing, loading or during cleanup and repair, wear
goggles or face shield, rubber apron, chemically resistant gloves, rubber boots, long
sleeved shirt and long legged pants.”
With

Add

“When handling the concentrate, mixing, loading or during cleanup and repair, wear
goggles or face shield, rubber apron, chemically resistant gloves, rubber boots, long
sleeved shirt and long legged pants. Wear long sleeved shirt, long legged pants and
chemical-resistant gloves during spraying application. Chemical resistant gloves are not
required to be worn during groundboom or aerial application. ”
“Apply only when the potential for drift to areas of human habitation or areas of human
activity such as houses, cottages, schools and recreational areas is minimal. Take into
consideration wind speed, wind direction, temperature inversions, application equipment
and sprayer settings.”
Directions for Use
Add


Not for use in greenhouses.
1 year plant back interval for all non-registered food and feed crops.
Environmental Hazards:
Add:
TOXIC to aquatic organisms and non-target terrestrial plants.
Observe buffer zones specified under DIRECTIONS FOR USE.
Toxic to certain beneficial insects. Minimize spray drift to reduce harmful effects on
beneficial insects in habitats next to the application site such as hedgerows and woodland.
Proposed Re-evaluation Decision - PRVD2016-11
Page 97
Appendix IX
To reduce runoff from treated areas into aquatic habitats avoid application to areas with a
moderate to steep slope, compacted soil, or clay.
Avoid application when heavy rain is forecast.
Contamination of aquatic areas as a result of runoff may be reduced by including a
vegetative strip between the treated area and the edge of the water body.
This product contains aromatic petroleum distillates that are toxic to aquatic organisms.
The use of this chemical may result in contamination of groundwater particularly in areas
where soils are permeable (for example, sandy soil) and/or the depth to the water table is
shallow.
Replace:
“Avoid spray drift. Avoid contamination of ponds, streams, rivers and desirable vegetation”.
OR
“Avoid contamination of aquatic systems during application. Do not contaminate these systems
through direct application, disposal of waste or cleaning equipment”.
With:
As this product is not registered for the control of pests in aquatic systems, DO NOT use to
control aquatic pests.
DO NOT contaminate irrigation or drinking water supplies or aquatic habitats by cleaning of
equipment or disposal of wastes.
Storage:
Replace:
May be stored at any temperature. SHAKE WELL BEFORE USING. Insecticides and
fungicides should be segregated from herbicides so as to prevent the possibility of cross
contamination.
With:
To prevent contamination, store this product away from food or feed
Proposed Re-evaluation Decision - PRVD2016-11
Page 98
Appendix IX
Buffer Zone Related Label Statements:
For products registered for aerial and field sprayer application, add:
Field sprayer application: DO NOT apply during periods of dead calm. Avoid
application of this product when winds are gusty. DO NOT apply with spray droplets
smaller than the American Society of Agricultural Engineers (ASAE S572.1) medium
classification. Boom height must be 60 cm or less above the crop or ground.
Aerial application: DO NOT apply during periods of dead calm. Avoid application of
this product when winds are gusty. DO NOT apply when wind speed is greater than 16
km/h at flying height at the site of application. DO NOT apply with spray droplets
smaller than the American Society of Agricultural Engineers (ASAE S572.1) medium
classification. To reduce drift caused by turbulent wingtip vortices, the nozzle
distribution along the spray boom length MUST NOT exceed 65% of the wing- or
rotorspan.
Buffer zones:
Use of the following spray methods or equipment DO NOT require a buffer zone: handheld or backpack sprayer and spot treatment.
The buffer zones specified in the table below are required between the point of direct
application and the closest downwind edge of sensitive terrestrial habitats (such as
grasslands, forested areas, shelter belts, woodlots, hedgerows, riparian areas and
shrublands) and sensitive freshwater habitats (such as lakes, rivers, sloughs, ponds,
prairie potholes, creeks, marshes, streams, reservoirs and wetlands).
Buffer Zone Table for products registered for aerial and field sprayer application:
Buffer Zones (metres) Required for the Protection of:
Freshwater Habitat of Depths:
Method of
application
Crop
Field sprayer
Seedling alfalfa,
highbush blueberry,
cranberry, coriander,
fenugreek, dry onion,
safflower, canola,
flax, field pea, lentils,
oriental (brown)
mustard (condiment
and oilseed types),
yellow mustard,
potato, soybean,
sunflower,
Less than 1 m
Greater than 1 m
1
1
Proposed Re-evaluation Decision - PRVD2016-11
Page 99
Terrestrial habitat
2
Appendix IX
Aerial
Spinach, dry common
bean, Desi and Kabuli
chickpea, Prairie
carnation
1
1
1
Canola,
flax, field
peas, lentils,
potatoes,
yellow
mustard,
brown
mustard,
soybeans,
sunflowers
Fixed
wing
10
1
60
Rotary
wing
10
1
50
Fixed
wing
4
1
30
Rotary
wing
1
1
30
Dry
common
bean, Desi
and Kabuli
chickpea
For tank mixes, consult the labels of the tank-mix partners and observe the largest (most
restrictive) buffer zone of the products involved in the tank mixture and apply using the
coarsest spray (ASAE) category indicated on the labels for those tank mix partners.
The buffer zones for this product can be modified based on weather conditions and spray
equipment configuration by accessing the Buffer Zone Calculator on the Pest
Management Regulatory Agency web site.
For products registered for field sprayer application only, add:
Field sprayer application: DO NOT apply during periods of dead calm. Avoid
application of this product when winds are gusty. DO NOT apply with spray droplets
smaller than the American Society of Agricultural Engineers (ASAE S572.1) medium
classification. Boom height must be 60 cm or less above the crop or ground.
DO NOT apply by air.
Buffer zones:
Use of the following spray methods or equipment DO NOT require a buffer zone: handheld or backpack sprayer and spot treatment.
The buffer zones specified in the table below are required between the point of direct
application and the closest downwind edge of sensitive terrestrial habitats (such as
grasslands, forested areas, shelter belts, woodlots, hedgerows, riparian areas and
shrublands) and sensitive freshwater habitats (such as lakes, rivers, sloughs, ponds,
prairie potholes, creeks, marshes, streams, reservoirs and wetlands).
Proposed Re-evaluation Decision - PRVD2016-11
Page 100
Appendix IX
Buffer Zones (metres) Required for the Protection of:
Method of
application
Field sprayer
Crop
Freshwater Habitat of Depths:
Terrestrial habitat
Less than 1 m
Greater than 1 m
Seedling alfalfa,
highbush blueberry,
cranberry, coriander,
fenugreek, dry onion,
safflower, canola,
flax, field pea, lentils,
oriental (brown)
mustard (condiment
and oilseed types),
yellow mustard,
potato, soybean,
sunflower,
1
1
2
Spinach, dry common
bean, Desi and Kabuli
chickpea, Prairie
carnation
1
1
1
For tank mixes, consult the labels of the tank-mix partners and observe the largest (most
restrictive) buffer zone of the products involved in the tank mixture and apply using the
coarsest spray (ASAE) category indicated on the labels for those tank mix partners.
The buffer zones for this product can be modified based on weather conditions and spray
equipment configuration by accessing the Buffer Zone Calculator on the Pest
Management Regulatory Agency web site.
Proposed Re-evaluation Decision - PRVD2016-11
Page 101
Appendix IX
Proposed Re-evaluation Decision - PRVD2016-11
Page 102
References
References
A.
Information Considered in the Chemistry Assessment
List of Studies/Information Submitted by the Registrant
PMRA Document
Number
1498825
2079982
2099718
1498830
2215011
2262172
2215009
2262172
2215009
637505
637508
637511
637512
637513
637514
637515
637509
637502
637503
1292788
637503
1292788
Reference
1995, Tomen's Responses to Reviewer's Questions, DACO: 2.99
2010, Cletodim Tecnico : Density, DACO: 2.14.6
2011, Clethodim Description of Manufacturing Process, DACO: 2.11, 2.11.1,
2.11.2, 2.11.3
1995, Specifications and Analytical Methodology Required for the Registration of
Clethodim Technical including appendices 1, 2, 3 and 4, DACO: 2.1,2.16
2012, Clethodim Technical: Description of Manufacturing Process, DACO: 2.0, 2.1,
2.11, 2.11.2, 2.11.3, 2.11.4, 2.12, 2.12.1, 2.13, 2.13.1, 2.13.2, 2.13.3, 2.13.4, 2.14,
2.2, 2.3, 2.3.1, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9
2009, AMENDED ANALYTICAL REPORT Batch Analysis of Clethodim and
Impurities, DACO: 3.0,3.1,3.3.1,3.4
2012, Clethodim: Product Chemistry Analysis, DACO: 2.0,2.12.1,2.13,2.13.2
2009, AMENDED ANALYTICAL REPORT Batch Analysis of Clethodim and
Impurities, DACO: 3.0,3.1,3.3.1,3.4
2012, Clethodim: Product Chemistry Analysis, DACO: 2.0,2.12.1,2.13,2.13.2
2003, Physical State, Shape, Colour And Odour Of Clethodim Agan Technical.,
DACO: 2.14.1,2.14.2,2.14.3
2003, Determination Of The Density Of Clethodim Agan Technical., DACO: 2.14.6
2003, Solubility Of Clethodim Agan Technical In Water And Organic Solvents.,
DACO: 2.14.7,2.14.8
2003, Vapour Pressure Of Clethodim Agan Technical., DACO: 2.14.9
2003, Dissociation Constants In Water Of Clethodim Agan Technical. B, DACO:
2.14.10
2003, Partition Coefficient (N-Octanol/Water) Of Clethodim Agan Technical.,
DACO: 2.14.11
2003, UV/VIS Absorption Spectra Of Clethodim Agan Technical., DACO: 2.14.12
2003, Thermal And Air Stability Of Clethodim Agan Technical., DACO: 2.14.13
2003, Description Of Starting Material.; Detailed Production Process Description;
Discussion of Formation of Impurities, DACO: 2.11.2,2.11.3,2.11.4
2003, Clethodim Technical Five Lots Analysis And Method Validation., DACO:
2.13.1,2.13.3
2006, Clethodim Technical - 5-Lots Analysis and Method Validation, DACO:
2.13.1,2.13.2,2.13.3
2003, Clethodim Technical Five Lots Analysis And Method Validation., DACO:
2.13.1,2.13.3
2006, Clethodim Technical - 5-Lots Analysis and Method Validation, DACO:
2.13.1,2.13.2,2.13.3
Proposed Re-evaluation Decision - PRVD2016-11
Page 103
References
B.
Information Considered in the Toxicological Assessment
List of Studies/Information Submitted by Registrant
PMRA Document
Number
1226179 and
1232645
1226180, 122618588, 1226982,
1231837 and
1234279
1226181 and
1232646
1226182 and
1232647
1226183 and
1232643
1226184 and
1232648
1227357
1227358
1227359
1227360
1227361
1227362
1227371-77,
1227379, 1227381,
1227451, 122745359, 1230580 and
1230582-85
1227382-91,
1227399 and
1234281
1227466
1227467
1227481
Reference
1986, Microbial/mammalian microsome mutagenicity plate incorporation assay
with RE-45601 technical (83.3% purity, SX-1688) (CEHC 2555), DACO: 4.5.4
1988, Chronic oral oncogenicity study in mice with Chevron RE-45601
technical (SX-1688)(2107-145), DACO: 4.4.2
1986, Microbial/mammalian microsome mutagenicity plate incorporation assay
with RE-45601 (83% purity, SX-1688)(SOCAL 2505), DACO 4.5.4
1986, Chromosome aberrations in Chinese hamster ovary (CHO) cells with
Chevron RE-45601 technical (T4529.337), DACO: 4.5.4
1987, Cytogenetics assay in bone marrow cells of rats following acute oral
exposure to RE-45601 technical (T5072.105), DACO: 4.5.4
1986, In vivo-in vitro hepatocyte DNA repair assay: in vitro evaluation of
unscheduled DNA synthesis (UDS) following oral administration of Chevron
RE-45601 technical to B6C3F1 mice (LSC-1960), DACO: 4.5.4
1988, Five week oral toxicity study in rats with RE-47719 (SX-1800)(CEHC
2949), DACO: 4.6.1
1988, Five week oral toxicity study in rats with RE-51228 (SX-1803). (CEHC
2950), DACO: 4.3.1
1988, Oral teratogenicity and developmental toxicity screen in rats with RE47719 (303-012), DACO: 4.5.2
1988, Oral teratogenicity and developmental toxicity screen in rats with RE51228 (303-010), DACO: 4.5.2
1988, Microbial/mammalian microsome plate incorporation mutagenicity assay
with RE-47719 (SX-1800) (CEHC 2948), DACO: 4.5.4
1988, Chromosome aberrations in Chinese hamster ovary (CHO) cells: RE47719 – Final toxicity report (TR226.337003), DACO: 4.5.4
1988, Combined chronic oral toxicity/oncogenicity study in rats with RE- 45601
technical (SX-1688) (SOCAL 2500), DACO: 4.4.1, 4.4.2.
1987, Two generation (one litter) reproduction study in rats with RE-45601
technical (CEHC 2596), DACO: 4.5.1
1988, The comparative acute oral toxicity of RE-47719 (SX-1800) and RE45601 technical (SX-1688) in adult female rats (2952), DACO: 4.2.1
1988, The comparative acute oral toxicity of RE-51228 (SX-1796) and RE45601 technical (SX-1688) in adult female rats (2951), DACO: 4.2.1
1987, Four-week repeated-dose dermal toxicity study in rats with RE-45601
technical (SX-1688) (CEHC 2552), DACO: 4.3.4
Proposed Re-evaluation Decision - PRVD2016-11
Page 104
References
PMRA Document
Number
1228811, 1228823,
1231978-79 and
1234282
1228837, 1228848
and 1228859
1229446
1229458
1229860-61
1229862 and
1232654
1229863 and
1232667
1229864 and
1232669
1229865 and
1232670
1229866 and
1232671
1229868 and
1232673
1229869, 1231831
and 1231977
1229870-71
1229872-74,
1229882 and
1232674
1229893 and
1231833
1229901
1227015 and
1232651
1371485-86
2308444
2308446
2308448
2308450
Reference
1987, Teratology study in rats with Chevron RE-45601 technical (86-3042),
DACO: 4.5.2
1987, Teratology study in rabbits with Chevron RE-45601 (303-007), DACO:
4.5.2
1987, Microbial/mammalian microsome plate incorporation mutagenicity assay
with RE-51228 (CEHC 2856), DACO 4.5.4
1988, Chromosome aberrations in Chinese hamster ovary (CHO) cells: RE51228 (T8227.337003), DACO: 4.5.4
1986, Acute oral toxicity study in mice with Chevron RE-45601 technical (SX1688)(2107-143), DACO: 4.2.1
1986, The acute oral toxicity of RE-45601 technical. (SX-1688) in adult male
and female rats (SOCAL 2498), DACO: 4.2.1
1986, The acute dermal toxicity of RE-45601 technical (SX-1688) in adult male
and female rabbits (CEHC 2510), DACO: 4.2.2
1986, The acute inhalation toxicity of RE-45601 technical (SX-1688) in rats
(CEHC 2513), DACO: 4.2.3
1986, The acute eye irritation potential of RE-45601 technical (SX-1688)
(CEHC 2511), DACO: 4.2.4
1986, The four-hour skin irritation potential of RE-45601 technical (SX-1688)
(CEHC 2512), DACO: 4.2.5
1986, Modified Buehler test for the skin sensitization potential of RE-45601
technical (SX-1688) (CEHC 2514), DACO: 4.2.6
1986, Four-week subchronic oral toxicity study in mice with RE-45601 technical
(SX-1688) (2107-140), DACO: 4.3.1
1986, Five week pilot feeding study in rats with RE-45601 technical (SX-1653)
(SOCAL 2457), DACO: 4.3.1
1986, 13-week oral toxicity study in rats with RE-45601 technical (SX-1688)
(SOCAL 2501), DACO: 4.3.1
1987, A ninety-day subchronic oral toxicity study in dogs with Chevron RE45601 technical (85-2999), DACO: 4.3.1
1988, One-year oral toxicity study in dogs with Chevron RE-45601 technical
(SX-1688) (2107-153), DACO: 4.3.1
1988, The in vivo metabolism of [Propyl-1-14C] clethodim in rats (2515)
(721.14), DACO: 6.4
2006, Clethodim technical: acute oral neurotoxicity (gavage) study in rats
(A76937), DACO: 4.5.12
2012, A 90-day oral dietary neurotoxicity study of clethodim in rats (194040)
(38046), DACO: 4.5.13
2012, A 28-day dietary dose range-finding neurotoxicity study of clethodim in
rats (194039) (38041), DACO: 4.5
2012, A 28-day oral (dietary) range-finding immunotoxicity study of clethodim
in female B6C3F1 mice (194037) (37831), DACO: 4.8(B)
2012, A 28-day oral (dietary) immunotoxicity study of clethodim in female
B6C3F1 mice (194038) (37839), DACO: 4.8(B)
Proposed Re-evaluation Decision - PRVD2016-11
Page 105
References
Additional Information Considered
i) Published Information
PMRA Document
Number
2456234
2456235
2456236
2456233
C.
Reference
2007, Clethodim: Human Health Risk Assessment for Proposed Uses on Herb
Subgroup 19A, Leafy Greens Subgroup 4A, Sesame seed, Safflower seed,
Legume Vegetable Group 6, Hops, Asparagus, and Flax seed. USEPA
Memorandum. PC Code: 121011, Petition Nos.: 4E6836, 5E6978, 4F6895,
5E6977, and 3E6555. DP Number: D323144, March 7, 2007
2008, Revised Clethodim Human Health Assessment Scoping Document in
Support of Registration Review. USEPA Memorandum. PC Code: 121011, DP
Number : D356151 & D349757, September 9, 2008
2014, Clethodim. Preliminary Risk Assessment for Registration Review. USEPA
Memorandum. PC Code: 121011, DP Number : D356151 & D349757, January
30, 2014
1993, Clethodim. Summary of Toxicology Data. California EPA. November 9,
1993
Information Considered in the Occupational and Non-Occupational Assessment
Registrant Submitted Studies/Information
PMRA Document
Number
1227004
1143600
2115788
Reference
THE PERCUTANEOUS ABSORPTION OF 14C - SELECT 2,0 EC (RE-45601)
IN MALE RATS (2774), DACO: 6.4
HERBICIDES: CLETHODIM: SELECT: A STUDY TO DETERMINE THE
EXPOSURE OF HERBICIDE APPLICATIORS TO CLETHODIM FROM
MIXING AND APPLYING SELECT (444-90PT;90-P1197;C080983;90-167PT),
DACO: 5.1
Agricultural Reentry Task Forces (ARTF). 2008. Data Submitted by the ARTF to
Support Revision of Agricultural Transfer Coefficients.
Additional Information Considered
i)
Published Information
None
ii) Unpublished Information
PMRA Document
Number
2381030
2381029
Reference
DACO: 5.8(A)_in_vivo_Review
DACO: 5.4_Review
Proposed Re-evaluation Decision - PRVD2016-11
Page 106
References
D.
Information Considered in the Dietary Assessment
Registrant Submitted Studies/Information
PMRA Document
Number
1058014
1058015
1065760
1065761
1065764
1065765
1065766
1148244
1148245
1157287
1160760
1160766
1171065
1171066
1175023
1175024
1175025
Reference
2005. Clethodim: Magnitude of the Residue on Coriander. Final Analytical Report.
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Appendix F of AAFC Study #AAFC03-046, pages 120-213 of 213 pages. GLP.
Unpublished.
2005. Clethodim: Magnitude of the Residue on Coriander. AAFC Study #
AAFC03-046, pages 1-119 of 213 pages. GLP. Unpublished.
1993. Confirmatory Method for the Determination of Clethodim and Clethodim
Metabolites in Crops, Animal Tissues, Milk, and Eggs, Method: EPA-RM-26D-2.
1994. PR Notice 88-5 Validation of Valents Confirmatory Method for the
Determination of Clethodim and Clethodim Metabolites in Crops, Animal Tissues,
Milk, and Eggs: Method EPA-RM-26D-2 (Revision February 1, 1993)
1990b. Freezer Storage Stability of Clethodim Residues on Cottonseed Processed
Parts.
1991. Freezer Storage Stability of Clethodim Residues on Soybean Processed Parts.
1988. Confined Rotational Crop Study of [Ring-4, 6-14C] Clethodim with Carrots,
Lettuce and Wheat. Chevron Chemical Company, Laboratory Project Identification
MEF-0036, 99 Pg.
1992. Herbicides: Clethodim: Select Residue Studies in Potatoes,Canada,1990-1991
(REF:92-001.DC)
1992. Herbicides: Clethodim: Select Residue Studies in Soybeans,Canada,19901991 (REF:92-002.DC)
1995. Herbicides: Clethodim: Select Residue Studies in Lentils Canada 1993-1994;
REF: 94-102.DC (January 1995)
1995. Herbicides: Clethodim: Select: Residue Studies in Alfalfa, Canada, 19931994.(REF:95-040.DC)
1995. Herbicides: Clethodim: Select: Residue Studies in Peas, Canada, 19931994.(REF:95-036.DC).
1996. Herbicides: Clethodim: Select. Residue Studies in Mustard, Canada, 19941995. April 1996. (REF:96-034.DC)
1996. Herbicides: Clethodim: Select. Residue Studies in Sunflower/Sunola, Canada,
1994-1995. April 1996. (REF:96-035.DC)
1998. Magnitude of Residues in Processed Sunflower Seed. Analytical Portions of
the Processing Study for Argentina. Date Stamped-"Received Health Evaluation
Division Mar 5 1998".(TMN-765;M-387;T-701).(Clethodim)
1998. Magnitude of Residues in Processed Sunflower Seed. Analytical Portions of
the Processing Study for Italy. Date Stamped-"Received Health Evaluation Division
Mar 5 1998".(TMN-569;0292-89;0266-91;0340-91).(Clethodim)
1996. Magnitude of Clethodim Residues In Sunflowers-Seeds And Processed Parts.
Date Stamped-"Received Health Evaluation Division Mar 18 1998".(V11186;MRID#44323402) [*Note-Page#317,529,532,536 Missing]
Proposed Re-evaluation Decision - PRVD2016-11
Page 107
References
PMRA Document
Number
1184497
1196377
1196378
1227015
1227023
1227024
1227025
1227026
1227027
1229447
1229468
1229471
1229469
1232663
1237305
1598359
1701888
1701890
2066127
2265024
Reference
1998. Residue Data Submitted in Support of Minor Use of 96-522, Select to Control
Annual Grasses on Dry Onions, Residue Trial Specification Form, Pesticide
Residue Report from Health Canada, Method, Example Chromatograms and
Laboratory Submissions Sheets and Copies of the Laboratory Reports
[Select;Regn.#22625]
2005.Clethodim: Magnitude of the Residue on Fenugreek. Study No. AAFC03-049.
Unpublished study prepared by Agriculture and Agri-Food Canada, Ottawa, ON.
209 pp.
2005. Clethodim: Magnitude of the Residue on Fenugreek. Final Analytical Report.
1988. The in vivo metabolism of [propyl-1-14C] clethodim in rats (2515)
1988. Plant metabolism study of [Ally-2-14C] Clethodim. Laboratory Project
identification: MEF-0005, Study Volume 1 of 1; File No.: 721.14/Clethodim. Dec.
22, 1988
1988. Plant Metabolism Study of [Ring-4,6-14C]-Clethodim in Carrots, Soybeans
and Cotton. TOMEN Report #149. Unpublished.
1988. Analytical Method for The Determination of Clethodim Residues (RM-26)
1988. Summary - Clethodim on Canola, Flax
1988. Select Residue Analysis 1988 Crops (Flax, Canola)
1988. The in Vivo Metabolism Of [Propyl-1-14C] Clethodim in Lactating Goat
(MEF-0038)
1988. [Ring-4,6-14C] Clethodim : A Radiocarbon Metabolism Study in Laying
Hens.
1989. Cow Feeding Study : Determination of Residues of Clethodim in Bovine
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1988. Analytical Methodology – Canola, Flax and Soybeans
1992. Confirmatory Method for the Determination of Clethodim and Clethodim
Metabolites in Crops, Animal Tissues, Milk and Eggs (RM-26D-1)
2001. Clethodim: Magnitude of the Residue on Spinach. Lab Project Number:
06243.99-NYR01. Unpublished Study Prepared by IR-4 Project at Rutgers, the
State University of New Jersey, North Brunswick, NJ. 261 pages.
1994. The Determination for Clethodim Residues in Crops, Chicken and Beef
Tissues, Milk and Eggs
Duplicate: PMRA# 1701951.
2008. Clethodim: Magnitude of the Residue on Blueberry. IR-4 PR No. 05234,
Laboratory Identification No. 05234.04-NYR17. Unpublished study prepared by
IR-4 Project Headquarters, Princeton, NJ. 265 pages.
Duplicate: PMRA# 1701953
1999. Clethodim: Magnitude of Residues in/on Cranberries.14-JUN-99. (IR4 PR#
05358)
Duplicate: PMRA#s 1095532, 2066155
2012. Clethodim: Magnitude of the Residue in and on Dill. Study Number
AAFC03-047, Laboratory Identification Number: AAFC03-047-200. Unpublished
study prepared by Pest Management Centre, Agriculture and Agri-Food Canada,
Ottawa, ON, 645 pages.
Duplicate: PMRA# 2265043
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References
PMRA Document
Number
2265069
2265170
2303325
2303339
2348144
Reference
2012. Clethodim: Magnitude of the Residue on Caraway. Study Number AAFC03044, Laboratory Identification Number: AAFC03-044-200. Unpublished study
prepared by Pest Management Centre, Agriculture and Agri-Food Canada, Ottawa,
ON, 237 pages.
2012. AAFC04-054 Clethodim in Caraway - Final Report - Supervised Residue
Trial Analytical Methodology.
2013. Aafc06-052 Centurion (Clethodim PCP#27598) Residue Report Radish Supervised Residue Trial Analytical Methodology.
Duplicate: PMRA#s 2303349, 2303370, 2303385, 2303402, 2303423
2013. Clethodim: Magnitude of the Residue on Carrot.” Study No. AAFC06-053R.
Laboratory Identification Number: AAFC06-053R-301. Unpublished study
prepared by the Pest Management Center, Agriculture and Agri-food Canada,
Ottawa, ON, 387 pages.
Duplicate: PMRA#s 2303321, 2303348, 2303369, 2303384, 2303456
2013. Residue Report - Clethodim: Magnitude of the Residue on Basil – Residue
Trial Analytical Methodology (Plant and/or Animal Commodities).
Duplicate: PMRA# 2348190
Additional Information Considered
Foreign Reviews
PMRA Document
Number
2536100
2536103
2536104
E.
Reference
JMPR, 1994. The Joint FAO/WHO Meeting on Pesticide Residues (JMPR) JMPR
Evaluation for Clethodim. JMPR no. (187)
JMPR, 1999. The Joint FAO/WHO Meeting on Pesticide Residues (JMPR) JMPR
Evaluation for Clethodim. JMPR no. (187)
JMPR, 2002. The Joint FAO/WHO Meeting on Pesticide Residues (JMPR) JMPR
Evaluation for Clethodim. JMPR no. (187)
Information Considered in the Environmental Risk Assessment
List of Studies/Information Submitted by Registrant
PMRA Document
Number
Reference
1074722
2002, ACUTE TOXICITY OF CLETHODIM 240 CE TO DAPHNIA MAGNA. BIOAGRI
LABORATORIOS LTDA. RF-0409.206.103.02. MAKHTESHIM-AGAN OF NORTH
AMERICA LTD., # 90004978. GLP, UNPUBLISHED., DACO: 9.3.5
1074729
2002, ACUTE TOXICITY OF CLETHODIM 240 CE TO EARTHWORM EISENIA
FOETIDA. BIOAGRI LABORATORIOS LTDA, RF-0409.203.109.02. MAKHTESHIMAGAN OF NORTH AMERICA LTD., # 90005050. GLP, UNPUBLISHED., DACO: 9.2.8
Proposed Re-evaluation Decision - PRVD2016-11
Page 109
References
1074730
2002, ACUTE TOXICITY OF CLETHODIM 240 CE TO FISH DANIO RERIO. BIOAGRI
LABORATORIOS LTDA, RF-0409.208.098.02. MAKHTESHIM-AGAN OF NORTH
AMERICA LTD., # 90004977. GLP, UNPUBLISHED., DACO: 9.5.4
1074731
2002, AVIAN ACUTE ORAL TOXICITY TEST OF CLETHODIM 240 CE IN JAPANESE
QUAILS (COTURNIX COTURNIX JAPONICA). BIOAGRI LABORATORIOS LTDA., RF0409.302.115.02. MAKHTESHIM-AGAN OF NORTH AMERICA LTD., # 90004975.
GLP, UNPUBLISHED., DACO: 9.6.4
1074732
2002, TOXICITY OF CLETHODIM 240 CE TO ALGAE PSEUDOKIRCHNERIELLA
SUBCAPITATA. BIOAGRI LABORATORIOS LTDA., RF-0409.202.095.02.
MAKHTESHIM-AGAN OF NORTH AMERICA LTD., # 90004979. GLP,
UNPUBLISHED., DACO: 9.8.6
1074744
2003, HYDROLYSIS OF CLETHODIM AGAN TECHNICAL AS FUNCTION OF PH.
BIOAGRI LABORATORIOS LTDA, RF-0409.012.038.02. MAKHTESHIM-AGAN OF
NORTH AMERICA LTD., # 90006023. GLP, UNPUBLISHED, DACO: 8.2.3.2
1074745
2003, PHOTOLYSIS IN WATER BY ARTIFICIAL SUNLIGHT OF CLETHODIM AGAN
TECHNICAL. BIOAGRI LABORATORIOS LTDA, RF-0409.013.047.02. MAKHTESHIMAGAN OF NORTH AMERICA LTD., # 90006022. GLP, UNPUBLISHED., DACO:
8.2.3.3.2
2003, SOIL ADSORPTION/DESORPTION OF CLETHODIM AGAN TECHNICAL.
BIOAGRI LABORATORIOS LTDA, RF-0409.027.044.02. MAKHTESHIM-AGAN OF
NORTH AMERICA LTD., # 90006025. GLP, UNPUBLISHED., DACO: 8.2.4.2
1074746
1074747
2002, ACUTE TOXICITY OF CLETHODIM AGAN TECHNICAL TO EARTHWORM
(EISENIA FOETIDA). BIOAGRI LABORATORIOS LTDA, RF-0409.203.110.02.
MAKHTESHIM-AGAN OF NORTH AMERICA LTD., # 90005080. GLP,
UNPUBLISHED., DACO: 9.2.3.1
1074748
2002, ACUTE CONTACT TOXICITY OF CLETHODIM AGAN TECHNICAL TO
HONEYBEES (APIS MELLIFERA) (AFRICANIZED). BIOAGRI LABORATORIOS
LTDA, RF-0409.204.117.02. MAKHTESHIM-AGAN OF NORTH AMERICA LTD., #
90005081. GLP, UNPUBLISHED., DACO: 9.2.4.1
1074749
2002, ACUTE ORAL TOXICITY OF CLETHODIM AGAN TECHNICAL TO
HONEYBEES (APIS MELLIFERA) (AFRICANIZED). BIOAGRI LABORATORIOS
LTDA, RF-0409.205.015.02. MAKHTESHIM-AGAN OF NORTH AMERICA LTD., #
90005082. GLP, UNPUBLISHED., DACO: 9.2.4.2
1074750
2002, ACUTE TOXICITY OF CLETHODIM AGAN TECHNICAL TO DAPHNIA MAGNA.
BIOAGRI LABORATORIOS LTDA, RF-0409.206.104.02. MAKHTESHIM-AGAN OF
NORTH AMERICA LTD., # 90005083. GLP, UNPUBLISHED., DACO: 9.3.2
1074751
2003, ACUTE TOXICITY OF CLETHODIM AGAN TECHNICAL TO FISH DANIO
RERIO. BIOAGRI LABORATORIOS LTDA, RF-0409.208.099.02. MAKHTESHIMAGAN OF NORTH AMERICA LTD., # 90005085. GLP, UNPUBLISHED., DACO: 9.5.2.1
1074752
2002, AVIAN ACUTE ORAL TOXICITY OF CLETHODIM AGAN TECHNICAL IN
JAPANESE QUAILS (COTURNIX COTURNIX JAPONICA). BIOAGRI LABORATORIOS
LTDA, RF-0409.302.116.02. MAKHTESHIM-AGAN OF NORTH AMERICA LTD., #
90005089. GLP, UNPUBLISHED., DACO: 9.6.2.3
Proposed Re-evaluation Decision - PRVD2016-11
Page 110
References
1074753
2003, AVIAN DIETARY TOXICITY TEST OF CLETHODIM AGAN TECHNICAL IN
JAPANESE QUAILS (COTURNIX COTURNIX JAPONICA). BIOAGRI LABORATORIOS
LTDA, RF-0409.303.027.02. MAKHTESHIM-AGAN OF NORTH AMERICA LTD., #
90004976. GLP, UNPUBLISHED., DACO: 9.6.2.6
1074754
2002, TOXICITY OF CLETHODIM AGAN TECHNICAL TO ALGAE
PSEUDOKIRCHNERIELLA SUBCAPITATA. BIOAGRI LABORATORIOS LTDA, RF0409.202.096.02. MAKHTESHIM-AGAN OF NORTH AMERICA LTD., # 90005079.
GLP, UNPUBLISHED., DACO: 9.8.2
1140881
1993, HERBICIDES: CLETHODIM: SELECT - SOIL DISSIPATION STUDY CANADA,
1992 (93-020.DC), DACO: 8.3.2.3
1150035
1993, HERBICIDES:CLETHODIM:SELECT SOIL DISSIPATION STUDY NOVA
SCOTIA, 1992 (REF:93-060.DC), DACO: 8.3.2.3
1226985
1988, HYDROLYSIS STUDY ON RE-45601 (MEF-0013/8703899), DACO: 8.2.1
1226986
1988, [4,6-RING-14C] - CLETHODIM PHOTODEGRADATION IN WATER (MEF-0024),
DACO: 8.2.1
1226987
1988, [ALLYL-2-14C] - CLETHODIM PHOTODEGRADATION IN WATER (MEF0025/8815098), DACO: 8.2.1
1226988
1988, CLETHODIM PHOTODEGRADATION ON SOIL (MEF-0022/88005410), DACO:
8.2.1
1226989
1988, FREUNDLICH SOIL ADSORPTION/DESORPTION COEFFICIENTS OF
CLETHODIM AND THREE METABOLITES (MEF-0102/8829844), DACO: 8.2.4.1
1226990
1988, THE AEROBIC SOIL METABOLISM OF CLETHODIM USING [RING-4,6-14C]
AND [ALLYL-2-14C] CLETHODIM (MEF-0015/0016/8819576), DACO: 8.2.3.1
1226991
1988, THE AEROBIC SOIL METABOLISM OF [PROPYL-1-14C] CLETHODIM (MEF0014/8721028), DACO: 8.2.3.1
1226992
1988, THE AEROBIC SOIL METHABOLSIM OF [RING-4,6-14C] CLETHODIM (MEF0063/8819578), DACO: 8.2.3.1
Proposed Re-evaluation Decision - PRVD2016-11
Page 111
References
1227450
1986, ACUTE TOXICITY OF CHEVRON RE-45601 TECHNICAL TO RAINBOW
TROUT IN A STATIC TEST SYSTEM (34968), DACO: 9.5.2.1
1227460
1988, CHARACTERIZATION OF 14C RESIDUES IN BLUEGILL SUNFISH TREATED
WITH [ALLYL-2-14C]-CLETHODIM OR [CYCLOHEXENE-1-ONE-4,6-14C]CLETHODIM, (MEF - 0020), DACO: 9.5.5
1227461
1987, UPTAKE, DEPURATION AND BIOCONCENTRATION OF [ALLYL-2-14C] AND
[CYCLOHEXENE-1-ONE-4,6-14C] RE-45601 TO BLUEGILL SUNFISH LEPOMIS
MACROCHIRUS (8728216), DACO: 9.5.5
1227462
1986, BEE ADULT TOXICITY DUSTING TEST (BATDT) EVALUATING THE
COMPARATIVE ACUTE CONTACT TOXICITY OF RE-45601 : 9433-16,87.9%
TECHNICAL SELECT TO HONEY BEE WORKER ADULTS (439), DACO:
9.2.4.1,9.5.2.1
1227464
1986, ACUTE TOXICITY OF CHEVRON RE-45601 TECHNICAL TO DAPHIA MAGNA
IN A STATIC TEST SYSTEM (34969), DACO: 9.3.1,9.5.2.1
1229455
1988, SELECT FIELD SOIL DISSIPATION STUDIES -CANADIAN SOIL DISSIPATION,
(86/090),DACO: 8.3.2.3
1229456
1986, RE-45601 TECHNICAL (SX-1688) : AN ACUTE ORAL TOXICITY STUDY WITH
THE BOBWHITE (162-165), DACO: 9.6.2.1
1229457
1986, RE-45601 TECHNICAL (SX-1688) : A DIETARY LC50 STUDY WITH THE
BOBWHITE (162-166), DACO: 9.6.2.1
1229459
1986, RE-45601 TECHNICAL (SX-1688) : A DIETARY LC50 STUDY WITH THE
MALLARD (162-167), DACO: 9.6.2.1
1229460
1987, RE-45601 TECHNICAL : A PILOT REPRODUCTION STUDY WITH THE
BOBWHITE COLINUS VIRGINIANUS (162-176), DACO: 9.6.3.1
1229461
1988, RE-45601 TECHNICAL : A ONE GENERATION REPRODUCTION STUDY WITH
THE BOBWHITE COLINUS VIRGINIANUS(162-183), DACO: 9.6.3.1
1229462
1987, RE-45601 TECHNICAL : A PILOT REPRODUCTION STUDY WITH THE
MALLARD ANAS PLATYRHYNCHOS (162-177), DACO: 9.6.3.1
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1229463
1988, RE-45601 TECHNICAL : A ONE-GENERATION REPRODUCTION STUDY WITH
THE MALLARD ANAS PLATYRHYNCHOS (162-184), DACO: 9.6.3.1
1229464
1986, ACUTE TOXICITY OF CHEVRON RE-45601 TECHNICAL TO BLUEGILL
SUNFISH IN A STATIC TEST SYSTEM (34967) (CON'T ON 756), DACO: 9.5.2.1
1231549
1989, EFFECTS OF SELECT 2EC ON NON-TARGET PLANT SPECIES (GREENHOUSE
DATA), DACO: 9.2.7
1233497
1990, TIER 1 VEGETATIVE VIGOR NONTARGET PHYTOXICITY STUDY USING
SELECT (CLETHODIM) (LR 89-54A), DACO: 9.8.6
1233498
1990, TIER 2 VEGETATIVE VIGOR NONTARGET PHYTOXICITY STUDY USING
SELECT (CLETHODIM) (LR 89-55A), DACO: 9.8.6
1233500
1990, TIER 2 SEED GERMINATION/SEEDLING EMERGENCE NONTARGET
PHYTOTOXICITY STUDY USING SELECT(CLETHODIM) (LR 89-55B), DACO: 9.8.6
1234270
1989, CLETHODIM: SELECT - SOIL DISSIPATION STUDY (90-312 DC), DACO: 8.3.2.3
1234271
1990, CLETHODIM: TOXICITY OF SELECT TO EARTHWORMS (E 310 0323-2),
DACO: 9.2.3.1
1234274
1990, LEACHING STUDY OF CLETHODIM & ITS MAJOR SOIL METABOLLITES BY
SOIL THIN-LAYER CHROMATOGRAPHY METHOD (MEF-142/9006840), DACO:
8.2.4.1
1234275
1990, THE AEROBIC AQUATIC METABOLISM OF [RING-4, 6-14C] CLETHODIM
(MEF-0140/9004982), DACO: 8.2.3.1
1234276
1990, THE ANAEROBIC AQUATIC METABOLISM OF [RING-4, 6-14C] CLETHODIM
(MEF-0141/9004983), DACO: 8.2.3.1
1234277
1990, THE AEROBIC SOIL METABOLISM OF CLETHODIM USING [RING-4, 6-14C]
AND [ALLYL-2-14C] CLETHODIM-REVISED JAN. 5, 1990 (MEF-0015/0016/8914823),
DACO: 8.2.3.1
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1990, ACUTE TOXICITY OF RE-45601 TECHNICAL TO THE FRESHWATER ALGAE
SELENASTRUM CAPRICORNUTUM PRINTZ (38373), DACO: 9.8.2
1234999
1990, ADDENDUM TO ACUTE TOXICITY OF RE-45601 TECHNICAL TO THE
FRESHWATER ALGAE SELENASTRUM CAPRICORNUTUM PRINTZ(S-3238-A),
DACO: 9.8.2
1307584
1998, IMPACTS OF AGRICULTURE ON SURFACE WATER QUALITY IN ALBERTA.
PART I: HAYNES CREEK STUDY, CAESA (CANADA - ALBERTA
ENVIRONMETALLY SUSTAINABLE AGRICULTURE AGREEMENT) ALBERTA
AGRICULTURE, FOOD AND RURAL DEVELOPMENT, DACO: 8.6
1307590
1995, OVERVIEW OF PESTICIDE DATA FOR ALBERTA SURFACE WATERS.
PHASE 2: SELECTION OF SOIL LANDSCAPE UNITS AND STUDY
DESIGN CONSIDERATIONS FOR THE SURFACE WATER QUALITY MONITORING,
CAESA , DACO: 8.6
1371483
2006, ANAEROBIC SOIL METABOLISM OF (C14) CLETHODIM, DACO: 8.2.3.4.4
1371484
2006, ASSESSMENT OF TOXIC EFFECTS OF CLETHODIM TECHNICAL ON THE
DUCKWEED LEMNA GIBBA IN A SEMI STATIC TEST, (20061137/01-AALG) DACO:
9.8.5
1560632
2003, PESTICIDE SAMPLING PROGRAM FOR SELECTED MUNICIPAL DRINKING
WATER SUPPLIES IN NEW BRUNSWICK.:TABLES 4-6: RESULTS BY
MUNICIPALITY AND QA/QC SAMPLES. DACO: 8.6
1640595
2003, PESTICIDE SAMPLING PROGRAM FOR SELECTED MUNICIPAL DRINKING
WATER SUPPLIES IN NEW BRUNSWICK, DACO: 8.6
2149073
2002, AGRICULTURE AND THE SUSTAINABILITY OF WATER QUALITY IN THE
ASSINIBOINE DELTA AQUIFER. MANITOBA CROP DIVERSIFICATION CENTRE.,
DACO: 8.6
2416279
1990, DATA EVALUATION RECORD. CITATION: PACK, D.E. 1988B. THE AEROBIC
SOIL METABOLISM OF CLETHODIM USING [RING-4, 6-14C]- AND [ALLYL-214C]CLETHODIM. LAB PROJECT ID MEF-0015/0016/8819576. UNPUBLISHED
STUDY PERFORMED AND SUBMITTED BY CHEVRON CHEMICAL COMPANY,
RICHMOND CA. MRID# 40974521 REVISED 1/5/90. MRID # 413768-01, DACO:
8.2.3.4.2
2416280
2006, EUROPEAN COMMISSION, DRAFT ASSESSMENT REPORT (DAR) - PUBLIC
VERSION - INITIAL RISK ASSESSMENT PROVIDED BY THE RAPPORTEUR
MEMBER STATE THE NETHERLANDS FOR THE EXISTING ACTIVE SUBSTANCE
CLETHODIM OF THE THIRD STAGE (PART A) OF THE REVIEW PROGRAMME
REFERRED TO IN ARTICLE 8(2) OF COUNCIL DIRECTIVE 91/414/EEC VOLUME 3,
ANNEX B, B.8, DACO: 12.5.8
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1990, CLETHODIM -NEW CHEMICAL REGISTRATION STANDARD, OFFICE OF
PESTICIDES AND TOXIC SUBSTANCES, USEPA, DACO: 12.5.8
2416283
2006, EUROPEAN COMMISSION, DRAFT ASSESSMENT REPORT (DAR) - PUBLIC
VERSION - INITIAL RISK ASSESSMENT PROVIDED BY THE RAPPORTEUR
MEMBER STATE THE NETHERLANDS FOR THE EXISTING ACTIVE SUBSTANCE
CLETHODIM OF THE THIRD STAGE (PART A) OF THE REVIEW PROGRAMME
REFERRED TO IN ARTICLE 8(2) OF COUNCIL DIRECTIVE 91/414/EEC VOLUME 3,
ANNEX B, B.9, DACO: 12.5.9
2416284
2011, EUROPEAN FOOD SAFETY AUTHORITY JOURNAL; 9 (10): 2417.
CONCLUSION ON PESTICIDE PEER REVIEW OF THE PESTICIDE RISK
ASSESSMENT OF THE ACTIVE SUBSTANCE CLETHODIM, DACO: 12.5.7
2416285
2007, ECOLOGICAL RISK ASSESSMENT EVALUATING CLETHODIM (PC 121011)
FOR THE PROPOSED NEW USE ON LEAFY GREENS, SESAME, SAFFLOWER,
HERBS, HOPS, ASPARAGUS, LEGUME; UNITED STATES ENVIRONMENTAL
PROTECTION AGENCY, DACO: 12.5.7
2416286
1999, FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS,
CLETHODIM (187), DACO: 12.5.7
2452948
2014, CLETHODIM: PRELIMINARY ECOLOGICAL RISK ASSESSMENT FOR
REGISTRATION REVIEW, UNITED STATES ENVIRONMENTAL PROTECTION
AGENCY, DACO: 12.5.9
2452949
2012, DATA EVALUATION RECORD - CITATION: CLETHODIM: A FLOWTHROUGH LIFE-CYCLE TOXICITY TEST WITH THE SALTWATER MYSID
(AMERICAMYSIS BAHIA), STUDY COMPLETION DATE: 2011. DACO: 12.5.9
2452950
2012, DATA EVALUATION REPORT ON THE TOXICITY OF CLETHODIM
TECHNICAL TO SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS), EARLY
LIFE STAGE, DACO: 12.5.9
2452951
2012, DATA EVALUATION RECORD- 72-3(B) -- ACUTE EC 50 TEST WITH AN
ESTUARINE/MARINE MOLLUSK SHELL DEPOSITION STUDY, CITATION:
CLETHODIM: A 96-HOUR SHELL DEPOSITION TEST WITH THE EASTERN OYSTER
(CRASSOSTREA VIRGINICA), STUDY COMPLETION DATE: 2011, DACO: 12.5.9
2452952
2012, TWO ECOTOXICITY DATA EVALUATION RECORD (DER) ADDENDUMS ON
ECOLOGICAL EFFECTS OFCLETHODIM ON TERRESTRIAL MONOCOT PLANT
SPECIES, UNITED STATES ENVIRONMENTAL PROTECTION AGENCY, DACO:
12.5.9
2452954
2014, UPDATE DER MRID 41685104 DOC#2049490 (PC CODE 121011- CLETHODIM) CITATION: TIER 2 SEED GERMINATION/SEEDLING EMERGENCE NONTARGET
PHYTOTOXICITY STUDY USING SELECT (CLETHODIM). LABORATORY PROJECT
NO. LR 89-55B. CONDUCTED BY PAN-AGRICULTURAL LABORATORIES, INC.,
FRESNO, CA. SUBMITTED BY VALENT USA CORPORATION, WALNUT CREEK,
CA. STUDY COMPLETION DATE: JUNE 28, 1990., DACO: 12.5.9
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2014, UPDATE DER MRID 41685105, DOC#2049491 (PC CODE 121011 - CLETHODIM)
- CITATION: TIER 2 VEGETATIVE VIGOR NONTARGET PHYTOTOXICITY STUDY
USING SELECT (CLETHODIM). LABORATORY PROJECT NO. LR 89-55A.
CONDUCTED BY PAN-AGRICULTURAL LABORATORIES, INC., FRESNO, CA.
SUBMITTED BY VALENT USA CORPORATION, WALNUT CREEK, CA. STUDY
COMPLETION DATE: MAY 29, 1990., DACO: 12.5.9
2452960
2008, REVISED CLETHODIM HUMAN HEALTH ASSESSMENT SCOPING
DOCUMENT IN SUPPORT OF REGISTRATION REVIEW, UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY, DACO: 12.5.9
2452961
2012, REVIEW OF THREE ECOTOXICITY STUDIES ON ECOLOGICAL EFFECTS OF
CLETHODIM, UNITED STATES ENVIRONMENTAL PROTECTION AGENCY,DACO:
12.5.9
2452962
2011, DATA EVALUATION RECORD ON THE CHRONIC TOXICITY OF CLETHODIM
AGAN TECHNICAL TO FRESHWATER INVERTABRATES - DAPHNIA SP.
CITATION: 2002, CHRONIC TOXICITY OF CLETHODIM AGAN TECHNICAL TO
DAPHNIA MAGNA. UNPUBLISHED STUDY PERDORMED BY BIOAGRI
LABORATORIES LTD., PIRACICABA, BRAZIL. LABORATORY STUDY NO. RF0409.207.032.02. STUDY SPONSORED BY AGAN CHEMICAL MANUFACTURERS
LTD., ASHDOD, ISRAEL. STUDY INITIATED JULY 10, 2002 AND COMPLETED
SEPTEMBER 30, 2002. DACO: 12.5.9
2463531
1988, CYCLOHEXANEDIONE HERBICIDES ARE SELECTIVE AND POTENT
INHIBITORS
OF ACETYL-COA CARBOXYLASE FROM GRASSES - PLANT PHYSIOLOGY,
VOLUME 86, PAGES 983 TO 986, DACO: 8.6
2475150
2010, INDIRECT PHOTODEGRADATION OF CLETHODIM IN AQUEOUS MEDIA.
BYPRODUCT IDENTIFICATION BY QUADRUPOLE TIME-OF-FLIGHT MASS
SPECTROMETRY - JOURNAL OF AGRICULTURAL FOOD CHEMISTRY, VOLUME
58, NUMBER 5, PAGES 3068 TO 3076, DACO: 8.2.3.3.2
2475152
2013, HERBICIDES - ADVANCES IN RESEARCH, CHAPTER 6, DEGRADATION OF
CYCLOHEXANEDIONE OXIME HERBICIDES, DACO: 8.2.3.3.2
2475154
1990, EFFECTS OF PH AND ADJUVANTS ON CLETHODIM PHOTODEGRADATION JOURNAL OF AGRICULTURAL FOOD CHEMISTRY, VOLUME 38, PAGES 875 TO
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