water supplies - Department of Defence

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part 3
CHAPTER 1
WATER SUPPLIES
INTRODUCTION
1
1.1
1.1
Environmental health personnel are involved with water supply because water is critical to
survival, yet also is a vehicle for transmission of many diseases, such as cholera, typhoid fever,
amoebiasis, shigellosis, poliomyelitis, and infectious hepatitis. See annex A for a discussion of
waterborne diseases.
1.2
Health personnel survey water supplies from source to consumer and recommend changes
necessary for the protection of Service members’ health. Responsibilities for field water supply include
duties for the medical officer and for health personnel. The following aspects of water supply are the
responsibility of the health services:
a.
Ensure water sources have been surveyed.
b.
Approve water for distribution.
c.
Establish disinfection chemical residual levels.
d.
Establish a recommended frequency for water point survey by health personnel.
e.
Recommend procedures to maintain water potability.
f.
Ensure water distribution equipment is regularly surveyed by health personnel.
g.
Approve the use of alternative water distribution equipment during extreme
emergencies.
DRINKING WATER QUALITY STANDARDS AND ANALYSIS
General
1.3
1.3
1.3
Drinking water is water which is intended to be used for maintaining adequate levels of
hydration and for nutritional purposes.
1.4
To be satisfactory for human consumption, water must be free of all pathogens or substances
in concentrations that can cause harmful effects. Water meeting these requirements is said to be
potable. Drinking water should also be palatable: that is, clear, cool and relatively free from unpleasant
taste and odour.
1.5
For logistic purposes, the daily drinking water requirement under temperate climatic conditions
is considered to be approximately five litres per person. Under extremely hot and humid conditions, such
as are present in Northern Australia, water consumption may substantially exceed five litres per day,
depending on the level of activity. Further information on this topic appears in part 5,
chapter 1—‘Introduction to common physical hazards’.
1.6
Australian Defence Force (ADF) field drinking water standards are contained in Quadripartite
Standardisation Agreement 245 (QSTAG–245)—Minimum Requirements for Water Potability, edition 2.
These standards are calculated on the basis of an intake of drinking water of five litres per day per soldier
and are categorised as short-term or long-term standards. Short-term field water consumption is for a
period of one to seven days; long-term field water consumption is for a period in excess of seven days.
1.7
Long-term deployments and ships. For water supply aboard ships and for field water supply
used by a deployed force for one month or longer it is desirable that it complies with the National Health
and Medical Research Council (NHMRC) Australian Drinking Water Guidelines 2004. Most of these
guideline values may be achieved by clarification and reverse osmosis treatment. Table 1–1
summarises QSTAG 245 and NHMRC standards while table 1–2 provides details on units of measure.
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1.8
At the individual level, the only standards that can be applied are the bacteriological standard
and the short-term physical standard. At small unit level, short-term standards only can be applied. At
major unit level and in static areas, the short-term standards apply for the first seven days, but after this
time, the long-term standards apply.
Serial
Parameter
ADF (NHMRC)
Long-term mg/L
QSTAG 245
Long-term
mg/L
QSTAG 245
Short-term
mg/L
QSTAG 245
Source
mg/L
6.5–8.5
5–9.2
5–9.2
5–9.2
5 (0.6 desirable)
1.5
1.5
500
1500(a)
1500
1500
5 (1 desirable)
1(b)
5(b)
50(b)
arsenic
0.007
0.05(c)
2
20
cyanide
0.08
0.5(c)
20
200
0.2
2
0.02
20
1
104 CFU/mL
Field Tests
1
Physical Characteristics
(turbidity, colour,
odour—sensory tests)
2
pH
3
Free chlorine (after
30–45 min)
4
Total dissolved solids (total
dissolved solids mg/L)
5
Turbidity (nephelometric
turbidity units)
6
Selected poisons
not objectionable
(c)
mustard
0.05
nerve agents
0.005(c)
7
Radioactivity
8
Total coliform bacteria
(CFU/100 mL)
9
Faecal coliform bacteria
in accordance with
NHMRC
0(e)
0.06 mCi/L
1
(d)
0
Complete Water Analysis
1
Hardness
200
2
True colour (Hazen Units
(HU))
15(f)
3
Ammonia
0.5
4
Cadmium
0.002
5
Chloride
250
6
Chromium (hexavalent)
0.05
7
Copper
2 (1 desirable)
8
Fluoride
1.5
9
Hydrogen sulfide
(sulphide)
0.05
10
Iron
0.3
11
Lead
0.01
12
Manganese
13
Nitrate
0.5 (0.1 desirable)
50
15
75
600
600
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14
Parameter
Sulfate (Sulphate)
1–3
ADF (NHMRC)
Long-term mg/L
QSTAG 245
Long-term
mg/L
500 (250 desirable)
400
Complete Water Analysis—Additional
QSTAG 245
Short-term
mg/L
QSTAG 245
Source
mg/L
400
(f)
1
Dissolved oxygen
85%
2
Aluminium
0.2
3
Barium
0.7
4
Boron
4
5
Mercury
0.001
6
Molybdenum
0.05
7
Nickel
0.02
8
Selenium
0.01
9
Silver
0.1
10
Zinc
3
QSTAG 245 Requirements (in addition to tests shown above)
1
Viruses (PFU/100 mL)
1
1
102 PFU/mL
2
Spores/cysts (CFU/100
mL)
1
1
104 CFU/mL
3
Temperature
15–22°C
4–35°C
4–35°C
4
Magnesium
150
-
150
Notes
(a)
Reverse osmosis treatment will desalinate source water with a TDS of 7500 mg/L. Some instruments
report conductivity or salinity (conversion from conductivity: 1 mS/cm conductivity x 0.5 = mg/L TDS).
(b)
Under QSTAG 245 Australia will accept a turbidity of 25 NTU (short-term), 5 NTU (long-term) and source
water at 500 NTU. Wherever possible, a turbidity of less than 5 NTU should be maintained.
(c)
For water intakes above five L/day, the contaminant level must be lowered proportionately (refer to
QSTAG 245).
(d)
Refer to QSTAG 245 for radiological guidelines.
(e)
If coliforms are detected then a repeat sample should be taken from the same site and tested for total
coliforms and faecal (thermotolerant) coliforms.
(f)
Up to 25 HU is acceptable if turbidity is low.
(g)
Refer to NHMRC Australian Drinking Water Guidelines 1996 for a complete listing of guideline values.
Table 1–1: Quadripartite Standardisation Agreement 245 and National Health and Medical
Research Council water standards
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Unit of measure
mg/L
milligrams per litre (also expressed as ppm—parts per million)
TDS
total dissolved solids
µS/cm
micro siemens per centimetre
µCi/L
micro Curies per litre
NTU
nephelometric turbidity units
HU
hazen units (colour units, also expressed as PtCo colour units)
CFU/100 mL
colony forming units per 100 mm
PFU/100 mL
plaque forming units per 100 mm
°C
degrees celsius
Table 1–2: Units of measure used in Quadripartite Standardisation Agreement 245 and National
Health and Medical Research Council water standards
1.9
Bacteriological standards:
a.
Since the concentration of pathogenic organisms in natural water and in drinking water
is generally very low, it is not practical to determine the number of these organisms to
decide whether or not the source and the finished water are safe. Instead of measuring
these organisms directly, health personnel accept indirect evidence from the presence
of so-called indicator organisms.
b.
The organisms selected as indicators are ones usually present in great numbers when
pathogens are present and that respond to the environment in the same manner as
pathogens. Furthermore, they are easily identified and counted by simple procedures.
Coliforms, the bacteria present in the intestinal tract of warm-blooded animals, have
been selected as the indicator organism because they meet these requirements. The
genera of coliform selected as an indicator of faecal contamination is E Coli. They can
be found in faecal wastes from man in large numbers (approximately 1011–1013 per
capita per day) and can be easily identified both numerically and qualitatively in
laboratories. The absence of coliform bacteria is considered evidence of
bacteriologically safe water. These bacteria are more resistant to the aquatic
environment and to disinfection than many pathogens of intestinal origin.
c.
The coliform group is not a species but consists of several genera of bacteria, some of
which are not found in the intestinal tract. The Aerobacter aerogenes, for example,
originate from soil or vegetation. The coliform group includes gram-negative,
nonspore-forming, rod-shaped bacteria which may be aerobic, facultative, or anaerobic.
Faecal coliform (or thermotolerant coliform) bacteria have the same fermentive
properties at 44–44.5°C.
d.
In the examination of water the membrane filter technique is used to identify the
presence of coliform bacteria. Other tests for coliforms exist and other indicator
organisms have been described. However, the ADF uses the membrane-filter technique
as the standard:
(1)
For the membrane-filter technique, the standard sample volume is 100 mL.
(2)
The maximum level for coliform contamination in field water supplies is one
coliform colony per 100 mL. However, it should be noted that occurrence of low
numbers of coliforms (up to 10 coliform organisms per 100 mL) in well maintained
water supply systems is common in Australia. When a standard sample for the
membrane-filter technique from a field water supply shows a larger number of
colonies than permissible, corrective actions by the water purification operators
must be taken and a new set of samples from the same sampling point must be
collected and examined daily until the results obtained from one set of samples
show the water to be of satisfactory quality. contains information regarding
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actions to take in the event that contaminated samples are found. The presence
of faecal coliforms at all is a matter for considerable concern. If the presence of
faecal coliforms is confirmed by re-sampling, immediate action should be
undertaken to determine the source of contamination, complemented by remedial
action.
1.10
Physical and chemical standards. There are several major health, aesthetic and economic
reasons for performing physical and chemical analysis for the constituents listed in table 1–1:
a.
pH affects water disinfection by chlorine.
b.
Temperature affects disinfection and user acceptance.
c.
Turbidity affects user acceptance, makes filtration more difficult and impairs contact
between chlorine and any organisms in the water. The efficiency of disinfection
decreases with increasing turbidity.
d.
Dissolved solids are found in all natural water. In fact, people become so accustomed
to drinking water which contains dissolved solids that pure distilled water tastes flat and
unpleasant. Generally, concentrations of dissolved solids are quite high before the water
becomes unpleasant. Highly mineralised water also deteriorates distribution systems
and domestic plumbing and appliances.
e.
Colour of an objectionable nature can cause Service members to reject otherwise safe
water supplies.
f.
Many substances which are soluble in water and could be found in water supplies are
toxic. At very low concentrations they may not be a health problem. However, in higher
concentrations there may be a risk to health, and the information below describes the
known potential health effects. The aim of reducing the levels of dissolved substances
in water to those set out under ‘Specific Dissolved Solids’ in table 1–1 is to reduce the
toxic risk to acceptable and safe levels for prolonged intake:
(1)
Arsenic (As). Arsenic is found in many foods in varying amounts. Its use in some
pesticides can be cause for concern because of the possibility of the entry of
these pesticides into food and water supplies. However, in Australia arsenic is not
generally present in waters. Arsenic is highly toxic and ingestion of as little as
5 mg can result in severe poisoning. Depending on the compound and its
dispersion, the single fatal dose for an adult person can range from 5 to 50 mg,
and in some cases up to 200–300 mg. Regular ingestion of arsenic will show
cumulative effects. A single dose may require 10 days for complete elimination
from the body. Arsenic is easily absorbed through the gastrointestinal tract and
lungs, and it is distributed throughout the body tissues and fluids. There is some
evidence that occupational long-term exposure to arsenic may cause cancer of
the lungs and skin. Physiological effects of severe arsenic toxicity include kidney
degeneration, oedema, liver cirrhosis, dermatitis and bone marrow injury. The
NHMRC guideline value is 0.007 mg/L; concentrations of arsenic in drinking
water up to this level have not been associated with adverse health effects, and
the presence of arsenic in drinking water is generally not a problem in Australia.
(2)
Cyanide (CN). Cyanide is toxic to man. However, the body is able to detoxify
cyanide by converting cyanide to thiocyanate if it is consumed in doses of less
than 10 mg. Usually, chlorination of water at a pH of less than seven will reduce
cyanide to a safe level. The NHMRC guideline value is 0.08 mg/L.
(3)
Mustard/Nerve Agents. Both are extremely toxic poisons capable of causing
severe injury.
(4)
Chloride (Cl). Limitations on the concentration of chlorides in drinking water are
set primarily because of palatability. Chlorides in high concentrations give water
a salty taste. The taste threshold generally is between 150 and 500 mg/L and
usually of the order of 400 mg/L. In Australia high levels of chloride in water are
usually associated with high sodium concentrations. Corrosion of hot water
supplies may also occur when high chloride concentrations are present. The
NHMRC guideline value is 250 mg/L based only on aesthetic considerations.
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(5)
Magnesium (Mg). In association with sulphate, magnesium can produce laxative
effects. Generally people adjust to this in time.
(6)
Sulphates (SO4). Limitations on the concentration of sulphates in water are set
primarily in consideration of taste considerations and their laxative properties.
Both sodium sulphate (Glauber’s salt) and magnesium sulphate (Epsom salts)
are well known laxatives. Calcium sulphate is also a laxative. Generally, the
threshold concentration for the laxative effect of sulphates is 500–700 mg/L. The
laxative effect of sulphates is commonly noted by tourists or other casual users of
water which is high in sulphates: however, regular users evidently become
acclimatised to the presence of the sulphates. The taste threshold for sulphate
ions is in the range of 200–500 mg/L. The NHMRC guideline value is 500 mg/L.
1.11
In addition to the chemicals listed in QSTAG 245, edition 2 with their minimum requirements,
there are other chemicals in water which are of interest from a health viewpoint. It should be kept in mind
that the NHMRC levels listed below are for long-term exposures and were not developed for field
exercises:
a.
Aluminium (Al). Aluminium compounds are used extensively in water treatment
resulting in levels in drinking water of up to 0.2 mg/L of total aluminium. There is no
conclusive evidence of health effects on normal individuals from the oral ingestion of
aluminium compounds unless there is an existing kidney disorder. At levels above
0.1 mg/L water may occasionally become opaque and discoloured. The presence of iron
enhances this effect. The NHMRC guideline value is 0.2 mg/L, based on palatability
concerns.
b.
Cadmium (Cd). Cadmium is a highly toxic element. It is found in ground waters as a
result of seepage from various sources such as electroplating plants. The zinc used to
galvanise iron is often contaminated with cadmium which may be released into the
water. The emetic threshold for cadmium is 13–15 mg/L. Cadmium accumulates in the
kidneys and liver. Physiological changes caused by cadmium include loss of bone
minerals and chronic kidney disease. A long-term tolerable intake is 0.5 mg per person
per week. Since cadmium can be found in air, food and water; only a portion of intake
can be from water. However, in Australia cadmium is usually absent from natural waters
or, if present, is usually at levels below 0.002 mg/L. Exceptions to this could include
waters derived from areas where there are substantial amounts of mine tailings.
NHMRC have recommended a limit of 0.002 mg/L in water.
c.
Carbon Dioxide (CO2). The presence of dissolved carbon dioxide in water also has an
effect on corrosion. In hard water, the amount of carbon dioxide present will determine
whether or not a protective layer of calcium or magnesium carbonate will be deposited
on the metal surface. The carbon dioxide, which forms carbonic acid in water, can
dissolve this protective layer or prevent deposits from forming. In soft water, the carbon
dioxide reacts with iron, releasing hydrogen into the water.
d.
Chromium (Cr). Sources of chromium in water include electroplating wastes and spent
battery acid. Chromium, when inhaled, is a known carcinogen. It is not known whether
chromium ingested with drinking water will cause cancer. The chromium of primary
concern is that in the hexavalent form (Cr6+). Recommend monitoring for total
chromium; the toxic hexavalent form should be determined if the NHMRC guideline
value (0.05 mg/L) is exceeded. NHMRC have recommended a limit of 0.05 mg/L (as
CR6+).
e.
Copper (Cu). Copper is a beneficial and essential element in human metabolism. A
deficiency in copper results in nutritional anaemia in infants. The daily adult copper
requirement has been estimated as 2 mg. Usually, a normal diet will satisfy this
requirement, but a supplement from water is not harmful. Copper does affect the
palatability of water, and the taste becomes perceptible with a concentration of one to
five mg/L. At four mg/L copper has been responsible for imparting a green tint to the hair
of silver blonde haired persons. Even at low concentrations, soluble copper salts are
potent, if somewhat unreliable, emetics. Acute poisoning from the ingestion of copper
salts is rarely severe, due to the emetic effect. However, if vomiting fails to occur or is
delayed, gradual absorption from the bowel may cause systemic copper poisoning. A
very large dose of copper can result in kidney and liver damage. High levels of copper
in drinking water are usually associated with corrosion of plumbing systems. NHMRC
recommend a limit of two mg/L for health considerations and one mg/L on a taste and
laundry staining basis.
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f.
Fluoride (F). A low level of fluoride in drinking water is effective in reducing the
incidence of dental caries. However, an excessive concentration (over three mg/L) will
result in increased mottling of tooth enamel (dental fluorosis) in children. Long-term
consumption of water containing fluoride concentrations greater than eight mg/L can
result in bone changes or crippling fluorosis. The optimum fluoride content for a water
supply is dependent on the average atmospheric temperature of the area, but it is
generally between 0.6 and 1.2 mg/L. Fluoride doses in excess of 2.25 g may be lethal.
However, in water adverse effects have not been noted even with levels up to
three mg/L. NHMRC recommended fluoride levels for drinking water vary from 0.5 to
1.5 mg/L depending on annual average maximum daily air temperature.
g.
Hardness. Hardness in water may be categorised as carbonate (temporary) hardness
or non-carbonate (permanent) hardness. Carbonate hardness is caused by the
carbonates of calcium and magnesium. The term temporary means that the calcium and
magnesium carbonates are precipitated from the water when the water is boiled. The
precipitate usually forms a soft light-coloured scale which can be removed from
accessible surfaces. A small amount of carbonate hardness is desirable in domestic
fresh water systems to control corrosion. This is particularly true in hot water distribution
systems where the service life otherwise would be greatly reduced. With the proper
amount of carbonate hardness a fine scale of calcium carbonate is deposited on the pipe
surface. This deposit prevents oxygen from reaching the metal surface, thus retarding
corrosion. Non-carbonate hardness includes chlorides, sulphates, and possibly nitrates
of calcium and magnesium. The evaporation of water containing these salts leaves a
highly corrosive residual (calcium chloride, magnesium sulphate and magnesium
chloride) and creates a hard brittle scale (calcium sulphate). The effect most often
observed from hardness is the great amount of soap required to form lather in hard
water. Hardness is mainly a problem in water obtained from groundwater.
h.
Iron (Fe). Iron is objectionable in water supplies because it imparts both taste and colour
to water. A concentration of 0.3 mg/L will cause staining of laundry and fixtures. A
somewhat higher concentration will cause a bitter taste. The flavour of coffee and tea
are affected if brewed with water containing substantial amounts of iron. Iron may enter
from the ground as a result of corroding water tanks and pipes, or from hill deposits of
iron ore in the water table. High levels of iron are commonly found in oxygen-depleted
waters such as groundwater and in bottom waters of reservoirs. It should be noted that
iron compounds are widely used in water clarification. The NHMRC guidelines value
based on aesthetics is 0.3 mg/L.
i.
Lead (Pb). Lead is a cumulative poison. It is absorbed from food, water and the
atmosphere. In Australia, food and air appear to be the most important sources of lead
intake, although rainwater can be contaminated in some cases. A total weekly intake of
more than three mg is considered unsafe. Lead sometimes enters water supplies as a
result of the corrosion of lead components in the system. Paints containing lead can be
a source of lead in a water supply. Reticulation systems incorporating lead pipes and
fittings are reported to be uncommon in Australia. Incorrect disposal of industrial waste
is also a source of contamination of water. Physiological effects of chronic exposure to
lead include anaemia, cramps and motor nerve paralysis. Severe encephalopathy can
occur with ingestion of large doses. NHMRC recommend limiting lead in water to
0.01 mg/L.
j.
Manganese (Mn). The effects of manganese in water are similar to those of iron
However, the taste and stain effects occur at lower concentrations. Manganese may
build up in distribution systems; if these coatings slough off, they can cause brown
blotches on laundry and black precipitates in the water. The taste of manganese in water
is similar to the taste of iron. The NHMRC guideline concentration is 0.5 mg/L for health
considerations and 0.1 mg/L for aesthetics.
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k.
Mercury (Hg). Mercury is widely distributed in the environment and is often found in
mining, agricultural and industrial discharges. Mercury is a cumulative poison. Fish is
the primary source for mercury in our diet: in this case the mercury is in the form of the
highly toxic alkyl mercury compounds rather than as inorganic mercury compounds.
Symptoms of mercury poisoning include pharyngitis, gastroenteritis, vomiting, bloody
diarrhoea and circulatory collapse. Central nervous system toxicity can occur and may
be indicated by severe headaches. NHMRC recommended level is 0.001 mg/L; this
level is reported to be unlikely to be exceeded in drinking water supplies in Australia.
l.
Nitrates (NO3). The presence of excessive concentrations of nitrates in water is
believed to cause methaemoglobinaemia (nitrate cyanosis). When consumed, nitrate is
converted to nitrite in the intestine. The nitrite attacks the haemoglobin in the blood,
converting it to methaemoglobin, which reduces the oxygen-carrying ability of the blood.
Wastes from chemical fertiliser plants and chemical fertilisers applied to crops are
possible sources of nitrates in drinking water. NHMRC recommend limiting nitrate in
water to 50 mg/L. This level is determined by health criteria for infants under one year
of age who are most at risk.
m.
Organic compounds. NHMRC guideline values for organic compounds, including
pesticides, in drinking water are shown in table 1–3.
n.
Oxygen (O2). The primary effect of dissolved oxygen is its corrosiveness. Iron corrodes
in natural waters at a rate roughly proportional to the concentration of dissolved oxygen
in the water. The solubility of oxygen in water decreases with increasing temperature
and decreasing pressure. Water in closed loops, such as closed heating and cooling
systems, becomes non-corrosive after a short time as the oxygen in the water is
consumed as the iron is oxidised. This condition will exist as long as no air or
replenishing water enters the system. A relatively large amount of dissolved oxygen in
natural water helps maintain the ecological balance. The addition of organic wastes,
such as sewage, quickly increases the oxygen demand and adversely affects the
aerobic biological systems in the waterway, causing putrefaction.
o.
Selenium (Se). Selenium is highly toxic. It is also believed to cause tumours and may
increase the incidence of dental caries. Some soils have a high selenium content.
Ground water from these areas may have a selenium content which is dangerously high.
NHMRC recommend 0.01 mg/L as a limit. In Australia, selenium is not usually detected
in drinking water supplies.
p.
Silver (Ag). Silver occurs naturally in the environment. The major potential problem
associated with silver in drinking water is that ingestion in concentrations appreciably in
excess of the recommended level over extended periods may result in skin, eyes and
mucous membranes turning a blue-grey colour. The effect may be permanent: once
absorbed, silver is held indefinitely in the tissues, particularly the skin. However, in high
concentrations over an extended period, other toxic manifestations may also become
apparent. Toxic effects may include kidney, liver and spleen pathologic changes,
especially at high levels (in excess of 400, 700 and 1000 mg/L, respectively). NHMRC
recommend 0.1 mg/L as a limit. However, silver is not known to be a problem in
Australian waters.
q.
Sodium (Na). A common component of drinking waters in Australia, particularly those
of groundwater origin. NHMRC recommended guideline value is 180 mg/L based on
aesthetics.
r.
Zinc (Zn). Zinc is essential to the human body and the average adult requires 10–15 mg
daily. Zinc concentrations in excess of 30 mg/L may cause nausea, vomiting and
fainting. Indicators of high concentrations are a metallic taste and a milky appearance in
water. NHMRC recommend limiting water concentration to three mg/L based on taste
considerations. High levels may be associated with corrosion of galvanised pipes and
fittings.
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Characteristic
Pesticides
Aldrin and Dieldrin (total)
Atrazine
Chlordane
Chlorpyrifos
DDT
Diquat
Heptachlor and Heptachlor
eposide (total)
Lindane (HCH)
Paraquat
Temephos
2, 4-Dichlorophenoxyacetic
acid (2,4-D)
Chlorinated alkanes and alkenes
Carbon tetrachloride
Tetrachloroethene
1, 1-Dichloroethene
1, 2-Dichloroethane
Polynuclear aromatic hydrocarbons
Benzo-a-pyrene
1–9
Guideline Value
(mg/L)*
Comment
0.0003
The pesticides listed are those which
are most likely to persist in Australian
water. Levels are based on acceptable
daily intake levels.
0.04
0.001
0.01
0.02
0.005
0.0003
0.02
0.03
0.3
0.03
0.003
These compounds are not considered
to be a significant problem in Australia
at present.
0.005
0.03
0.06
0.00001
An indicator of pollution by toxic
polynuclear aromatic hydrocarbons.
Coal-tar and coal-tar epoxy linings are
a recognised source of contamination.
Chlorophenols
2,4,6-Trichlorophenol
0.02
Chlorophenols are formed as a result
of chlorination of water containing
phenols.
Aromatic hydrocarbons
Benzene
0.001
An indicator of the presence of
petrochemicals.
Disinfection by-products
Trihalomethanes
0.25
Part of a complex array of by-products
of chlorination. Action to reduce
trihalomethanes is encouraged, but
must not compromise disinfection.
*refer to the NHMRC Australian Drinking Water Guidelines publication for a complete listing of their
organic compounds standards.
Table 1–3: Organic compounds in drinking water—guideline values
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1.12
1.13
1–10
Radiological Standard:
a.
For short-term consumption, no absolute maximum tolerance is recommended or
considered necessary. This is based on the conclusion that if the risk of external
radiation is such as to allow the water source to be used, then the water will be suitable
for drinking during occupancy not exceeding one week. Water which has been
deliberately contaminated with radioactive substances must in no case be used for
consumption.
b.
For long-term consumption, QSTAG 245 recommends a limit of 0.06 mCi/L.
c.
Types and Frequency of Testing.
The four types of ADF field water analysis and normal frequencies of testing are:
a.
Field tests (carried out on reconnaissance and upon establishment of a water point).
b.
Routine testing of an established water point (carried out at least once per week).
c.
Complete water analysis (on long-term deployments upon establishment of a water
point and then as ordered).
d.
Complete water analysis—additional tests (carried out as ordered).
1.14
Preventive medicine/environmental health personnel should ensure that field drinking water
supplies are tested and reports issued in a timely manner to the Senior Medical Officer and to the senior
water treatment representative. The frequency of testing may be increased in cases of suspected
contamination.
Field tests
1.15
1.15
Field tests are carried out during reconnaissance of potential water points and are the first tests
carried out on treated water (including water drawn from existing civilian supplies). The field tests are the
minimum required to determine water potability in the combat zone, unless there are obvious signs of
pollution due to enemy action or occurring naturally. These tests must be carried out or commenced on
site. Local authorities or residents may be able to give information on the presence of total dissolved
solids (in the form of salinity or hardness) or poisons.
1.16
Field tests consist of:
a.
Physical characteristics (taste, colour, odour and temperature).
b.
pH.
c.
Free chlorine (after addition).
d.
TDS.
e.
Turbidity.
f.
Selected poisons (if presence is suspected; normally arsenic and cyanide and may
include mustard and nerve agents).
g.
Radioactivity (as ordered).
h.
Total coliform bacteria (carried out by preventive medicine/environmental health
personnel).
i.
Faecal coliform bacteria (carried out by preventive medicine/environmental health
personnel).
1.17
Tests for chloride, magnesium and sulfate (sulphate) may be ordered to satisfy QSTAG 245
while analysis for total chlorine and chlorine demand may also be of use at some water points. Poisons
tests must be carried out in areas that have been subject to nuclear, biological or chemical (NBC)
operations or recently occupied by the enemy.
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1.18
1–11
The field tests provide a guide to the most suitable treatment measures.
1.19
Where ever possible preventive medicine/environmental health personnel should accompany
the water treatment personnel on water point reconnaissance to assist with the conduct of field tests. All
water treatment personnel must be capable of carrying out the field tests in paragraph 1.16. Additional
samples should be collected and dispatched to preventive medicine/environmental health personnel for
further analysis. Complete water analysis will not normally be possible in the combat zone.
Routine testing of an established water point
1.20
1.20
Once the quality of a water point is established the following tests are routinely conducted to
ensure that the water remains potable and palatable. Changes in these parameters may provide the first
warning of adverse changes in water quality or treatment malfunctions. The following tests are routinely
carried out:
a.
Physical characteristics (taste, colour, odour and temperature).
b.
pH.
c.
Free chlorine.
d.
TDS.
e.
Turbidity.
f.
Total coliform bacteria (carried out by preventive medicine/environmental health
personnel).
g.
Faecal coliform bacteria (carried out by preventive medicine/environmental health
personnel).
1.21
Water point operations should conduct routine testing on a daily basis (testing free chlorine,
pH, TDS/conductivity and turbidity).
1.22
The frequency of routine testing by preventive medicine/environmental health personnel
depends on operational requirements, but should be carried out at least once per week. Tests by
preventive medicine/environmental health personnel for pH, free chlorine, TDS and turbidity may be
recommended on a daily basis.
Complete water analysis
1.23
1.23
A complete water analysis should be conducted on field water supplies intended to be used by
a deployed force for one month or longer.
1.24
Complete water analysis, which is a preventive medicine/environmental health responsibility,
provided a quantitative measure of impurities known to be harmful or likely to affect the method of water
treatment required. Complete water analysis must be carried out before any new source of treated water
is used to supply a permanent or semi-permanent installation and regularly thereafter, and in operational
areas as directed by the staff. A complete water analysis, and additional tests as necessary, should be
conducted in response to events which may result in contamination (eg heavy rain washing
contaminants into a surface water source).
1.25
Complete water analysis consists of the field tests with the addition of the following:
a.
Hardness.
b.
True colour.
c.
Ammonia.
d.
Cadmium.
e.
Chloride.
f.
Chromium.
g.
Copper.
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h.
Fluoride.
i.
Hydrogen sulfide (sulphide).
j.
Iron.
k.
Lead.
l.
Manganese.
m.
Nitrate.
n.
Sulfate (Sulphate).
1–12
Complete water analysis—additional tests
1.26
1.26
A preventive medicine/environmental health laboratory will conduct additional tests on
long-term deployments and in the case of suspected contamination. These tests assume greater
significance when water is supplied in large qualities or for extended periods. The frequency of additional
tests will be specified for long-term deployments.
1.27
The complete water analysis—additional tests consists of:
a.
Confirmation or completion of analysis for poisons (including arsenic, cyanide).
b.
Confirmation or completion of other complete water analysis tests (as required).
c.
Dissolved oxygen.
d.
Aluminium.
e.
Barium.
f.
Boron.
g.
Mercury.
h.
Molybdenum.
i.
Nickel.
j.
Selenium.
k.
Silver.
l.
Zinc.
1.28
The preventive medicine/environmental health laboratory may also carry out tests for
temporary and permanent hardness and alkalinity.
Interpretation of results
1.29
1.29
Water analysis reports contain statements on the suitability of water for drinking and the
treatment required based on the presence of contaminants. Preventive medicine/environmental health
personnel will advise the Senior Medical Officer on the suitability of a water source for use. Although the
interpretation of water analysis reports is a preventive medicine/environmental health responsibility, it is
important for water treatment personnel to understand the significance of the results. Table 1–1 contains
a summary of guideline values.
1.30
When water is produced by Quadripartite forces (United States of America, United Kingdom,
Canada and Australia) on combined operations it should meet the Minimum Requirements for Water
Potability (Short- and Long-term Use) standards set out in QSTAG 245. Under QSTAG 245 Australia will
use source water with a turbidity up to 500 NTU and accept treated water up to 25 NTU for short-term
consumption and up to five NTU for long-term consumption.
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1.31
The ADF long-term standards (analysed by complete water analysis) are based on the
NHMRC Australian Drinking Guidelines 1996. Although these standards are not designed for field
deployments, most may be achieved by the application of clarification and reverse osmosis treatment.
1.32
References. The NHMRC Australian Drinking Water Guidelines 1996 and QSTAG 245
provide information of water sampling, treatment and the interpretation of water analysis results and
these references should be carried by preventive medicine/environmental health personnel in the field.
1.33
Water of lower standards. In emergency situations the consumption of drinking water which
does not satisfy the ADF standards may be authorised. In such cases the Senior Medical Officer must
consider potential short-term and long-term health effects. The long-term standards are calculated with
a safety margin. In the case of some contaminants the guideline value is intended to protect an individual
from the chronic effects of a life time consumption while, on a military deployment an individual is likely
to be exposed for a period of 12 months or less. When considering the approval of water of lower
standards the following factors should be considered:
a.
The target population. The presence of some contaminants will be more dangerous to
a population containing infants, children, pregnant women, the elderly, the sick and the
immunocompromised than to a healthy military population.
b.
Exposure duration.
c.
Contaminant effects. The time after which effects may be expected, toxicity, target
organs and the modes of exposure (ingestion, inhalation, skin contact) should be
considered.
d.
Daily water consumption level.
Presence of Other Contaminants (defined by National Health and Medical Research Council)
1.34
1.34
If the presence of other chemicals or contaminants, not included in the ADF complete water
analysis or those parameters not suitable for field analysis, is suspected then samples should be referred
to an accredited civilian laboratory. This includes tests for inorganic chemicals not listed above, other
disinfection agents and disinfection by-products, organic chemicals, pesticides and toxic algae.
1.35
In the case of some parameters, the ADF test kits will only detect gross contamination but not
trace concentrations. The determination of more accurate concentrations may require referral to an
accredited civilian laboratory.
Water quality for non-consumptive uses
1.36
1.36
Standards are applied to water for non-consumptive purposes to prevent infection from contact
with or ingestion of contaminated water and to prevent deterioration of equipment and clothing.
1.37
Potable water. Potable water (water which satisfies the drinking water standards) must be
used for food preparation and utensil cleaning, ice production, personal hygiene (showering, shaving,
cleaning teeth), washing clothing, medical treatment, photo processing and the cleaning of water supply
and purification equipment. As a minimum requirement water for personal hygiene must be disinfected
and free from poisons. Drinking water for animals must be free from excessive salinity and poisons.
1.38
Clarified water. Water which has been clarified, but not necessarily disinfected, should be
used for vehicle radiators, boilers and pest control and is recommended for vehicle washing and
firefighting. In the long-term, the use of excessively hard or saline water will result in scaling and/or
corrosion.
1.39
Untreated water. Untreated water, which is reasonably free of suspended matter, may be
used for decontamination, vehicle washing and firefighting. Water subject to NBC contamination is
decontaminated by reverse osmosis treatment.
1.40
Water for recreational use. Water for recreational use may include fresh and saline inland
waters and marine and estuarine coastal waters. The NHMRC Australian Guidelines for the Recreational
Use of Water 1990 provides a full description of guideline values. It is recommended that water for
swimming has less than 600 faecal coliforms per 100 mL in four out of five samples (with a median value
not exceeding 150 faecal coliforms per 100 mL for five samples taken at least monthly). Swimming pools
must be treated in accordance with health authority guidelines. Cold water pools must have a free
chlorine of at least one mg/L while higher concentrations are required for pools stabilised with
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isocyanuric acid and for heated or indoor pools. Further details are contained in health authority
publications such as Department of Health NSW Public Swimming Pool and Spa Pool Guidelines 1996
and NHMRC Australian Guidelines for Disinfecting Private Swimming Pools 1989.
WATER SOURCES
General
1.41
1.41
1.41
Water may be derived from surface or ground water sources including existing facilities.
Surface water sources are easy to develop, but are very susceptible to pollution and chemical agent
contamination. Ground water sources are less likely to be contaminated, but require special well drilling
equipment and more time for development. Existing facilities that have been damaged can be repaired
or modified for use. This section provides background material to assist health personnel in evaluating
the available water sources:
a.
Surface water sources are classified as fresh, brackish, or salt water (seawater)
depending on the concentration of TDS. Fresh water has a TDS concentration of less
than 1500 mg/L. Brackish waters are high in minerals and have a TDS concentration
between 1500 mg/L and 15 000 mg/L. Salt waters have a TDS concentration greater
than 15 000 mg/L.
b.
Generally, ground water has fewer chemical or biological contaminants than surface
water, provided reasonable care is exercised in the selection of a well drilling site.
However, in many locations in Australia, ground water is likely to be brackish. Sodium
is a common component of drinking waters in Australia, particularly those of
groundwater origin, and is frequently associated with high chloride concentrations.
Harmful micro-organisms are usually reduced to tolerable levels by filtration through the
soil. Ground water rarely requires treatment other than disinfection, unless its TDS
content is greater than 1500 mg/L.
1.42
In some circumstances existing water facilities can be put to use with less expenditure of time,
effort and equipment than it would take to develop a new field source. All water produced from existing
facilities will be considered unsafe until evaluated by health personnel and declared potable by the Unit
Medical Officer (MO).
1.43
All water sources which have not been tested by health personnel and approved by an MO as
potable will be labelled as ‘NON POTABLE WATER—DO NOT DRINK’. Such sources include
construction water points, untested taps, tanks, vehicle washing points, etc.
1.44
Regardless of who is responsible for water sources reconnaissance, a member of a preventive
medicine unit or other qualified health personnel should be included to survey and test the source water
for health hazards.
Health considerations
1.45
1.45
General guidelines:
a.
If local water systems are adequate to supply both civilian and military needs, they may
be used. However, additional chlorination may be required.
b.
When ground water is available in sufficient quantity, it may be preferable subject to its
meeting the required TDS levels. However, the amount available is usually impossible
to determine quickly. This will frequently preclude the use of ground water as a source
of supply at engineer water points.
c.
Ordinarily, surface water is used as the source of water in the field. It can usually be
treated easily by engineer water supply units with issue water treatment equipment.
d.
Water which is contaminated with sewage, no matter how little, must be regarded as
dangerous and totally unfit for human consumption.
1.46
Water reconnaissance or survey. Regardless of whether surface sources are still bodies of
water such as lakes and ponds, or moving water such as rivers, streams and springs, they should be
investigated for pollution. Surface sources receive the run-off from the catchment areas in which they lie.
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Major sources of pollution, such as municipal or private sewage and other waste, can be identified by
such means as area reconnaissance, map references, and information from local inhabitants. Field
water points must be located as far from sources of pollution as practicable. Other information must be
obtained and considered before establishing a field water point:
a.
Quantity of water. The quantity must be sufficient to meet the water requirements.
b.
Quality of water. Water should be of such quality that it can be readily treated with
normal field equipment. Chemical, chlorine demand, pH and other tests will be done to
determine if the source can be made potable. Additional tests may be necessary if other
contaminants are evident or suspected.
c.
Accessibility. A satisfactory water point must be accessible to vehicles and personnel.
Especially desirable features are a good road net with turnarounds, cover and
concealment of the water point and a suitable parking area. The road should be
adequate to withstand vehicle traffic under all weather conditions. Drainage, security of
the area and a suitable area for bivouac of personnel should also be considered.
1.47
Blue-green algae (Cyanophyceae). Of all the causes of taste and odour problems in water,
algae are the most important. Blue-green algae is frequently responsible for taste and odour in water
supplies. At high concentrations, blue-green algae is responsible for killing fish and causing illness in
animals and humans. Probably the most effective and common treatment for preventing the growth of
algae is the application of copper sulfate at moderate doses of approximately 0.3 mg/L. Fortunately,
most fish can tolerate doses up to about 0.5 mg/L. Chlorine is also used to control the growth of algae.
Experience has shown that concentrations of free residual chlorine between 0.2 and 1.0 mg/L are
effective in destroying algae.
WATER TREATMENT
Individual clarification
1.48
1.48
1.48
The individual equipment used to filter water is the Millbank Individual Filter. It is a green,
chain-weave bag of stout cotton, treated to render it rot- and mould-proof. It measures
140 x 140 x 20 mm, weighs 20 g, and can be carried in a soldier’s basic webbing. The weave of the bag
filters out suspended matter (including amoebic, a protozoa, cysts) while allowing the water to pass
through and discharge into a water bottle from one of the bottom corners of the bag which runs to a point.
The procedure is as follows:
a.
Thoroughly wetting the bag. As the material is nearly waterproof it is necessary for it
to be thoroughly wet before use. This is done by turning the bag inside out and soaking
the lower part, up to the black line, in water.
b.
Reversing the Bag. The bag is turned back to its correct side out.
c.
Filling the bag to the top. The bag is filled to the top with the Cup Canteen or some
other suitable container to avoid dirtying the outside of the bag.
d.
Suspending the bag. The filter is attached to a stake or tree branch, using the eyelets
in the top of the bag.
e.
Allowing the first half litre to run to waste. The first half litre is allowed to run to waste
to clean the external surface of the bag.
f.
Filling the water bottle. When the water level reaches the black line a water bottle is
placed below the lowest point. The filtered water will run down the outside of the bag to
the pointed end and drip into the bottle. Providing the bag is thoroughly wet a bottle will
fill within five to eight minutes.
WARNING
The bag is not to be squeezed or the hole size enlarged at the pointed end of the bag.
g.
Disinfection. After filtering, the water must still be disinfected.
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Figure 1–1: Millbank individual filter
Coagulation, sedimentation, filtration and reverse osmosis
1.49
1.49
Coagulation and sedimentation:
a.
Through coagulation and sedimentation, particles that could rapidly clog filters are
removed. Chemical coagulation involves the formation of a heavy gelatinous mass (floc)
which settles rapidly. As the floc settles, it forms larger and larger masses and collects
the suspended particles. The most common coagulants in use today are aluminium
sulphate (alum), ferric chloride, and ferrous sulphate. After the coagulant is added to the
water, mixing is necessary to distribute the chemical throughout the water and to aid in
floc formation. Mixing can be accomplished in baffled basins or by mechanical agitation.
Flocculation can be accomplished by slow-moving paddle wheels, operating in a tank
having a detention period of 20–40 minutes. After these processes are completed, the
water is received in sedimentation basins, where the floc rapidly settles out.
b.
The basic processes of chemical mixing, coagulation and sedimentation can be
accomplished in a single tank. Decreased chemical consumption results when the
entering raw water makes intimate contact with previously formed sludge. This process
provides treatment in a smaller space and in a shorter time.
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1.50
Filtration. The production of clear, potable water usually requires filtration. A rapid sand filter,
the type commonly used, consists of a bed of sand or other media about one metre thick. The sand
removes some bacteria, finely divided clay and suspended matter not removed by coagulation and
sedimentation. During filtration, the water flows through the sand bed into a clear well for storage.
Filtration continues until the resistance to flow by material removed by the filter becomes excessive. Flow
through the filter is then reversed to clean the sand particles. This process is called backwashing.
1.51
Reverse osmosis. Desalination is the conversion of seawater or brackish water to freshwater.
The ADF commonly uses reverse osmosis for desalinating seawater or brackish water. Normally if
saltwater and freshwater are separated by a semipermeable membrane, the freshwater diffuses through
to the saltwater as if under pressure, actually osmotic pressure. In reverse osmosis, pressure of up to
1500 psi is applied to the saltwater on one side of a special flat or cylindrical supported membrane or
hollow fibre. In the process freshwater is separated out from the saltwater into a porous or hollow
channel from which the freshwater is collected. In reverse osmosis the saltwater to be treated must be
relatively clear and free of excessive hardness and organic matter to prevent fouling of the system
membranes. Reverse osmosis is effective in desalinating water, as well as in removing pathogenic
micro-organisms.
Disinfection
1.52
1.52
Disinfection. For disease control, disinfection is the most important step in treatment of water
because other operations do not assure removal of all the disease producing organisms. Disinfection is
therefore included in all ADF water treatment. Disinfection of water may be accomplished in a number
of ways, but the cheapest, most effective and most widely used method is chlorination. Water that has
been treated efficiently by the process of coagulation, sedimentation and filtration will facilitate effective
chlorination. For this reason, chlorine is often applied to raw water (pre-chlorination) to improve
coagulation and control undesirable growths of algae and related organisms that increase the filter
loading. The addition of chlorine after the treatment processes (post-chlorination) to destroy the
remaining pathogens and provide a residual disinfectant for potential subsequent contamination is
essential.
1.53
Chlorine residual and pH requirements. The disinfectant normally used for water supplies
is chlorine, which is commercially available as sodium hypochlorite (liquid bleach; contains
12–15 per cent available chlorine) and calcium hypochlorite (granular or tablet form; contains
65 per cent available chlorine):
a.
The effectiveness of chlorine as a bactericidal agent depends upon the amount of
chlorine present, the contact period, the temperature, and pH. Effectiveness is
enhanced with an increase in the amount of chlorine present and with an increase in the
contact period. Since chlorine, like other chemicals, reacts more rapidly at higher
temperatures, its disinfecting ability increases with elevations in temperature. However,
chlorine should not be used in hot water because the chlorine is lost too rapidly to be
effective as a disinfectant.
b.
The effectiveness of chlorine increases as the pH decreases. When chlorine is
introduced into water, it forms hypochlorous acid and hypochloric acid. Hypochloric acid
is of little value as a disinfectant. Hypochlorous acid exists in a molecular and ionised
form, the proportion of each dependent on the pH. The molecular form of hypochlorous
acid is uncharged and is the more effective disinfectant because it can diffuse more
readily through the membranes of micro-organisms than can the charged or ionised
form of hypochlorous acid. The lower the pH, the greater the percentage of the
molecular form of hypochlorous acid Therefore, chlorine is more effective as a water
disinfecting agent at a low pH.
c.
An understanding of chlorine dosage and demand is essential in defining the meaning
of chlorine residual:
(1)
Chlorine dosage. Chlorine dosage is the amount of chlorine added to water.
Dosage is expressed as a concentration, normally in terms of milligrams per
litre (mg/L).
(2)
Chlorine demand. Chlorine in water rapidly oxidises organic matter including the
portions of micro-organisms that must be oxidised to inactivate them. In these
reactions, chlorine is reduced to chloride and is no longer available as a
disinfectant. Inorganic matter, such as iron or manganese, also consumes
chlorine. Chlorine demand is the amount of chlorine participating in these
oxidation reactions during a specified contact period.
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Residual chlorine. Residual chlorine is the concentration of chlorine remaining
after the chlorine demand has been satisfied. Maintenance of a chlorine residual
in a water system is important to provide continuing protection against pathogens
introduced into the system through such occurrences as cross-connections and
line breaks. Residual chlorine can be divided into several types:
(a)
Free available chlorine. Free available chlorine refers to the hypochlorous
acid present in water. This is the most effective form of chlorine for
disinfection.
(b)
Combined available chlorine. Chlorine added to water that contains
ammonia or organic nitrogen reacts and forms compounds called
chloramines. Chlorine combined in this manner is still available for
disinfection but is much less effective. This form of chlorine is called
combined available chlorine.
(c)
Total available chlorine. The total available chlorine is the sum of the free
available chlorine and the combined available chlorine.
d.
Field chlorination. Field treatment units employing coagulation, filtration and/or
reverse osmosis are capable of removing a high degree of suspended solids. When
these units are employed, a free available chlorine residual of two mg/L after a 30
minute contact time must be maintained at the point of production. A reduction in free
chlorine occurs as drinking water is stored and transported, although a concentration of
one mg/L must be maintained in unit level distribution containers and 0.1 mg/L or
greater must be maintained at the point of consumption. The concentration at the point
of consumption will depend on the conditions of storage and the degree of clarification
of the water. Drinking water must only be held in cleaned and disinfected containers
(such as tankers, tanks and jerry cans) which should be checked for adequate chlorine
concentrations.
e.
Higher chlorine concentrations. In cases of poor clarification, treated water
temperatures below 15°C or the presence of micro-organisms such as Entamoeba
histolytica, Giardia lamblia or Cryptosporidium parvum, a free chlorine concentration of
up to 5 mg/L after a 30 minute contact time may be recommended by the Senior Medical
Officer. A free chlorine concentration of up to five mg/L may also be authorised if water
is being stored for extended periods or transported over long distances in order to
maintain a concentration of 0.1 mg/L or greater at the point of consumption.
f.
Water drawn from existing reticulated supplies. Sources which have a free chlorine
of less than two mg/L, such as reliable reticulated town supplies, may be approved for
immediate use in the local area. A satisfactory free chlorine concentration can not be
maintained if this water is transported over long distances or stored for long periods.
Water drawn from town water supplies must still be tested by preventive
medicine/environmental health personnel.
g.
Fixed installations. When water is supplied to the distribution system of a fixed
installation, a measurable chlorine residual must be maintained at all times in the parts
of the system where water circulation is continuous. A measurable chlorine residual may
not be required when the water is stored for long periods in properly protected
distribution reservoirs, or when iron, manganese, or other chlorine-consuming
compounds would make the maintenance of such a residual impractical. If sanitary
deficiencies are known or suspected, the concentration of chlorine in the water
produced must be two mg/L.
WATER SAMPLING
General
1.54
1.54
1.54
There are many factors that affect the quality and safety of water for human use. The first and
usually the most important of these factors from a medical standpoint is the presence of living organisms
in the forms of bacteria, protozoa, helminths, plankton, viruses, algae and by-products of these
organisms. The pathogenic organisms are of primary concern to the MO. The non-pathogenic organisms
have some medical significance because their presence indicates both inadequate disinfection and
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additional chlorine demand. Even dead organic matter in water is of some medical significance for the
same reason. Chemical contaminants of either an organic or inorganic nature, such as dissolved
minerals, toxins and industrial wastes, greatly affect the sanitary quality of water for human use and may
be of far greater health significance than pathogenic organisms. Permissible amounts of various
biological and chemical contaminants in field water supplies are listed in table 1–1.
1.55
Sampling. The ADF is directly involved in collecting and testing water samples for
bacteriological and chemical analysis and interpreting the findings. Each sample container should be
clearly marked with a sample number which relates to details recorded on a water analysis results sheet.
The following general principles should be observed when sampling:
1.56
a.
Properly representative bacteriological and chemical samples must be taken from the
same point at the same time.
b.
In piped supplies, samples should be taken from the mains as well as from taps.
c.
When samples are collected from creeks and dams, the bottle must be held well below
the neck and either held upstream, or swept in an arc approximately 300 mm below the
surface in such a manner that water flowing into the bottle can not pass over the hand.
d.
When collecting samples from bores and taps, the pipe or tap must be flamed and then
the water run to waste for three minutes before sampling.
Water analysis results sheets should record:
a.
The date and time of sampling.
b.
The location and type of source.
c.
The name of member who collected the sample.
d.
The treatment the water is known to have received, such as chlorination or clarification.
e.
Types of samples collected, such as samples for chemical and bacteriological analysis.
f.
Note possible sources of contamination of the water, such as cattle grazing nearby.
Bacteriological analysis of water
1.57
1.57
Samples of water for bacteriological analyses must be collected in sterile bottles. Screwcap
bottles of about 120 mL capacity are preferred, but glass stoppered bottles or commercially provided
closable plastic containers are acceptable. These bottles must have been cleaned, capped with a
protective hood of paper or foil and sterilised in an autoclave. Before the bottles are sterilised, 0.1 mL of
10 per cent sodium thiosulphate solution must be placed in each bottle to neutralise any chlorine
residual which may be in the water at the time of collection. Such neutralisation prevents the chlorine
from killing any living organisms in the water samples after collection.
1.58
Collect the sample by first flaming the tap and then opening the tap to allow the water to flow
for three minutes to clear the line. While waiting for the line to clear of sitting water determine the chlorine
residual and pH and record that data and number the sample bottle. Record the location of the sample
collection.
1.59
Adjust the flow to prevent splash and to protect the sample bottle from contamination.
1.60
Remove the hood and bottle cap together; place the bottle under the tap and fill it to the base
of the neck. Do not overfill and do not rinse the sample bottle.
1.61
Replace the cap and hood on the bottle. Whenever possible samples should be held at 4°C
and analysed within six hours (do not hold longer than 24 hours).
1.62
Use the membrane filter technique to determine the coliform count in the sample.
1.63
Determine if the samples meet the standard for bacteriologically safe water.
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Chemical analysis of water
1.64
1.64
As a general rule samples for chemical analysis should be collected in 1 L polypropylene
bottles which have been washed with 1:1 nitric acid and rinsed with deionised water. The bottle may be
rinsed with sample water at the time of collection. Samples of water for chemical analysis must meet
differing sampling requirements for each type of chemical. Current manufacturers literature and water
laboratory requirements must be followed regarding sample collection and analysis.
Chlorine levels and pH
1.65
1.65
Chlorine levels and pH are tested using a Lovibond Comparator.
WATER SUPPLY HEALTH SURVEY
1.66
1.66
Health personnel will perform periodic surveys of water treatment, storage and distribution
systems to ensure acceptable levels of hygiene are maintained.
1.67
Surveys of water points should include the material outlined in annex C. Storage and
distribution equipment will be maintained in a sanitary state in accordance with the equipment’s technical
manuals.
HYGIENE ASPECTS OF WATER DISTRIBUTION
1.68
1.68
Distribution equipment. The distribution of large quantities of potable water under field
conditions may be accomplished by pipeline, hoseline, semitrailer and tank trucks. Smaller quantities will
be picked up from storage and distribution points in tank trucks, water trailers and water cans.
1.69
Storage equipment. Units in the field may be equipped with a variety of water storage
equipment including canteens, water cans and water trailers.
1.70
Emergency water containers:
a.
General. An adequate number of potable water containers may not always be available
to support a mission. Circumstances such as destruction in combat, unexpected
interruption of supply, or isolation from friendly forces may force a unit commander to
use containers which are not approved for use with potable water.
b.
Approval for Use. Approval to use alternative containers under emergency conditions
will be requested by the unit commander from the operation commander if conditions
permit. The Senior Medical Officer will recommend approval or disapproval of the
request.
c.
Types of alternative containers:
(1)
(2)
Non-potable water containers:
(a)
Water containers normally used to haul non-potable water for construction
purposes may be used in support of combat emergencies when potable
water containers are unavailable.
(b)
Other military non-potable water containers include fire brigade and
bushfire brigade water tankers.
Liquid food product containers:
(a)
Civilian containers normally used to transport liquid food products may be
used in support of combat emergencies when potable water containers are
unavailable.
(b)
Liquid food product containers include those used to transport milk, syrups,
juices, vegetable oils, wines etc.
UNCONTROLLED IF PRINTED
HLTHMAN, volume 20
part 3
1.71
1–21
Equipment cleaning:
a.
Requirements. The owning unit will maintain the cleanliness of unit water trailers and
other water purification, storage and distribution equipment. Water trailers will be clean
upon arrival at a water point. Water purification and distribution personnel will refuse to
fill unclean containers. Unit commanders will ensure water trailers and other potable
water containers are inspected for cleanliness, tightness of seals and seams, and
overall ability to perform their intended purpose. The unit will coordinate the regular
maintenance and cleaning of water containers to ensure that the quality of potable water
is not altered.
b.
Frequency:
(1)
New equipment. New equipment (such as water tanks, trailers and other
containers) will be cleaned and sanitised prior to initial use. Once new equipment
has been designated for use with potable water, it will not be contaminated with
any non-potable water or fuel. The words POTABLE WATER ONLY will be
stencilled on both sides of the equipment’s exterior.
(2)
Routine cleaning. On an annual basis all equipment associated with the
production, storage and distribution of potable water will be inspected, cleaned
and sanitised. Routine equipment cleaning helps ensure continued availability of
the equipment for unit support and reduces the potential for the spread of
infectious disease. This equipment will be free from defects such as excessive
rust, corrosion, or chipping to internal surfaces and inlet or outlet devices that
could result in contamination of the distributed or stored potable water. Defective
equipment will be repaired or replaced per applicable technical manuals.
c.
Field cleaning. Potable water containers which become dirty inside while in the field
must be cleaned prior to arrival at a water point. This cleaning will be performed as
needed. To prevent dirt, leaves, windblown dust and other contaminants from entering
water containers, the unit commander must ensure the containers remain properly
sealed. Manhole covers, spigot box covers and filling ports should be kept closed and
dust caps should be attached to dispensing valves when water is not being drawn from
the container.
d.
Procedures. A detailed description of procedures for routine and emergency cleaning
of new and used equipment is provided in annex D.
1.72
Equipment used to store or transport potable water will be sanitised after cleaning in
accordance with instructions presented in annex D.
Annexes:
A.
Waterborne diseases
B.
Actions to take when contaminated water samples are found
C.
Guide for water point survey
D.
Water storage and transport equipment cleaning and sanitising instructions