MICRONUTRIENT AND HEAVY METAL CONCENTRATIONS OBSERVED IN NATURAL WETLAND MACROPHYTES IN ARIZONA By Laska Rohovit Thesis Submitted to the Faculty of the DEPARTMENT OF SOIL, WATER AND ENVIRONMENTAL SCIENCE In Partial Fulfillment of the Requirements For the Degree of MASTER OF SCIENCE In the Graduate College THE UNIVERSITY OF ARIZONA 1999 2 STATEMENT OF AUTHOR This thesis has been submitted in partial fulfillment of requirements for an advanced degree at the University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. Signed: APPROVAL BY THESIS DIRECTOR This thesis has been approved on the date shown below: 3 ACKNOWLEDGMENTS I would like to sincerely thank Dr. Janick Artiola in the Department of Soil, Water and Environmental Sciences, Dr. Martin Karpiscak in the Office of Arid Lands Studies, and Dr. Ed Glenn in the Department of Soil Water and Environmental Sciences for their guidance throughout this research. I would also like to thank Jeff Conn for his assistance in both the field and laboratory. I am grateful to Dr. Chris Amrhein and Jim Strong at the University of California, Riverside for granting me use of their facilities and instrumentation. 4 TABLE OF CONTENTS Page LIST OF FIGURES 6 LIST OF TABLES 7 ABSTRACT 9 CHAPTER 1: BACKGROUND INFORMATION 10 Factors Necessitating Research 10 Constructed Wetland Treatment Systems 10 Environmental Factors Affecting Elemental Accumulation 14 Physiological Factors Affecting Elemental Accumulation 17 Literature Review 18 CHAPTER 2: RESEARCH OVERVIEW 28 Site Selection 28 Plant Species Selection 33 Elemental Analysis 33 Data Analysis 35 CHAPTER 3: METHODS AND TECHNIQUES 38 Sample Collection 38 Sample Preparation 39 Sample Analysis 42 CHAPTER 4: RESULTS AND DISCUSSION 44 Aluminum 44 Arsenic 48 Cadmium 52 5 TABLE OF CONTENTS — Continued Page Chromium 54 Cobalt 57 Copper 59 Iron 63 Lead 67 Manganese 71 Nickel 75 Selenium 77 Zinc 80 CHAPTER 5: CONCLUSIONS 84 APPENDIX A: EMPIRE CIENEGA 89 APPENDIX B: CANELO HILLS CIENEGA 91 APPENDIX C: PATAGONIA-SONOITA CREEK PRESERVE 93 APPENDIX D: ST. DAVID CIENEGA 95 APPENDIX E: AGUA CALIENTE PARK 97 APPENDIX F: COOK'S LAKE 99 APPENDIX G: BINGHAM CIENEGA 101 APPENDIX H: COMPLETE PLANT DATA BY STUDY SITE 103 REFERENCES 107 6 LIST OF FIGURES Page Figure 1: Life forms of aquatic macrophytes commonly used in constructed wetland systems 13 Figure 2: Selected wetland locations throughout Southern Arizona 30 Figure 3: Mean copper concentrations in the tissues of wetland macrophytes 62 Figure 4: Mean iron concentrations in the tissues of wetland macrophytes 66 Figure 5: Mean lead concentrations in the tissues of wetland macrophytes 70 Figure 6: Mean manganese concentrations in the tissues of wetland macrophytes 74 Figure 7: Mean zinc concentrations in the tissues of wetland macrophytes 83 7 LIST OF TABLES Page Table 1: Major chemical forms of trace elements in soil solutions and aqueous environments 15 Table 2: Summary of trace metal concentrations in freshwater plants from uncontaminated environments 19 Table 3: Approximate concentrations of trace elements in mature leaf tissue generalized for various species 20 Table 4: Trace element content of a "reference plant" 22 Table 5: Selected chemical parameters in plant tissue samples from potable and effluent-fed constructed wetland systems 24 Table 6: Selected chemical parameters in plant leaf, root and flower samples from potable and effluent-fed constructed wetland systems 26 Table 7: Elemental concentrations in emergent, submerged and floating-leaved life forms of aquatic and wetland plants 27 Table 8: Selected sites, wetland types and ownership 29 Table 9: System of categories for determining the occurrence of wetland plants 34 Table 10: Selected plant species and their wetland categories 34 Table 11: Selected elements and their biological classifications and functions 36 Table 12: Sampling schedule 38 Table 13: Plant tissue samples collected at each of the seven sites 40 Table 14: Summary of nutrient and heavy metal concentrations observed in the tissues of selected naturally occurring wetland macrophytes in Arizona 45 Table 15: Aluminum concentrations observed in naturally occurring wetland macrophytes 46 Table 16: Nutrient and heavy metal concentrations observed in water samples from natural wetland sites in Arizona 47 8 LIST OF TABLES - Continued Page Table 17: Nutrient and heavy metal concentrations observed in soil samples from natural wetland sites in Arizona 49 Table 18: Arsenic concentrations observed in naturally occurring wetland macrophytes 50 Table 19: Cadmium concentrations observed in naturally occurring wetland macrophytes 53 Table 20: Chromium concentrations observed in naturally occurring wetland macrophytes 55 Table 21: Cobalt concentrations observed in naturally occurring wetland macrophytes 58 Table 22: Copper concentrations observed in naturally occurring wetland macrophytes 60 Table 23: Iron concentrations observed in naturally occurring wetland macrophytes 64 Table 24: Lead concentrations observed in naturally occurring wetland macrophytes 68 Table 25: Manganese concentrations observed in naturally occurring wetland macrophytes 72 Table 26: Nickel concentrations observed in naturally occurring wetland macrophytes 76 Table 27: Selenium concentrations observed in naturally occurring wetland macrophytes 78 Table 28: Zinc concentrations observed in naturally occurring wetland macrophytes Table 29: Summary of nutrient and heavy metal concentrations in the tissues of macrophytes reported for various environments 81 87 9 ABSTRACT The use of macrophytes for the treatment of wastewater in constructed wetlands has caused concern over the possible concentration of elements within plant tissues. To better understand the potential of constructed wetland systems for adverse impacts, research was conducted to determine ranges at which micronutrients and heavy metals naturally exist in the root, shoot and leaf tissues of wetland plants in southern Arizona. Lemna sp., Anemopsis californica and Scirpus americanus concentrated the highest levels of micronutrients and heavy metals. Leaves of tree and shrub species usually had the lowest micronutrient and heavy metal concentrations of the plants analyzed in this study. Root tissues generally had higher concentrations of most elements, although elevated concentrations of micronutrients and heavy metals were found in the shoots of Typha domingensis and the leaf tissues of Anemopsis californica. 10 CHAPTER 1: BACKGROUND INFORMATION Factors Necessitating Research Constructed wetland systems have proven to be a cost-effective, viable alternative to traditional wastewater treatment and an environmentally sound method for polishing wastewater (Karpiscak et al., 1996; Cole, 1998). However, the rapid rate at which wetlands are being constructed, with over 500 operational in Europe and 600 in North America, has caused some concern over the impact of such systems (Debusk et al., 1996; Cole, 1998). Many studies have demonstrated that concentrations of essential and nonessential elements are substantially higher in plant tissues than in sediments and the surrounding aquatic environment (Outridge and Noller, 1991; Albers and Camardese, 1993a). Bioconcentration of the nutrients and heavy metals present in wastewater may pose a risk to animal inhabitants of constructed wetlands as well as to human health. Elemental concentration may also lead to the production of toxic plant biomass, which should be handled in an appropriate manner upon wetland harvesting. An inadequate understanding of the degree to which nutrients and heavy metals are concentrated in the tissues of macrophytes within constructed wetland treatment systems has prompted this research. Constructed Wetland Treatment Systems Ecosystems dominated by aquatic macrophytes are known to be some of the most productive environments in the world (Brix and Schierup, 1989). With this in mind, researchers have exploited the ability of macrophytes to acquire and assimilate nutrients 11 by the construction of wetlands for agricultural and municipal wastewater treatment. In addition, macrophytes have been found to remove heavy metals by uptake and immobilization within plant tissues, making them suitable for mine drainage and industrial wastewater treatment (Gupta et al., 1994; Dushenko et al., 1995; GoodrichMahoney, 1996; Knight et al., 1999). Constructed wetland systems have been investigated internationally for several decades, and their capacity to reduce levels of pathogens, suspended solids, biochemical oxygen demand (BOD), nutrients and heavy metals has been documented (Reed et al., 1988; Martin and Fernandez, 1992; Karpiscak et al., 1996, Knight et al., 1999). Constructed wetland systems rely on the sun and gravity for energy, and the soil, plant and microorganism matrix to retain and degrade the contaminants found in wastewater (Goodrich-Mahoney, 1996). Wetland vegetation acts to slow effluent flow, allowing for the sedimentation of suspended particles (Juwarkar et al., 1995), while assimilating nutrients and heavy metals from the sediments and ambient water into new plant biomass (Brix and Schierup, 1989). Perhaps more importantly, wetland vegetation acts as a substrate for large and diverse microbial populations. Translocation of oxygen through the plant body creates an aerobic microenvironment at the rhizosphere, where microorganisms degrade nutrient, organic and metal pollutants and mediate chemical reactions (Knight et al., 1995; Goodrich-Mahoney, 1996). The physical, biological and chemical reactions that occur in wetlands allow contaminants of differing characteristics to be physically removed, adsorbed to surfaces, or chemically transformed and stored within the wetland matrix (Gersberg et al., 1986; Goodrich-Mahoney, 1996). 12 A variety of vegetation has been used in wetland systems designed for wastewater treatment, including large trees and emergent, submergent and floating-leaved aquatic macrophytes. Brix and Schierup (1989) illustrated the major life forms of aquatic macrophytes commonly used in constructed wetlands (Figure 1). Large trees such as cottonwood, ash and willow are often found in natural wetlands, but their use in constructed wetlands is sparse, as their function in the treatment system has not yet been defined. Emergent aquatic macrophytes dominate in engineered systems because of their extensive root systems, with Typha (cattail), Scirpus (bulrush) and Phragmites (common reed) being the most commonly propagated species (Havens et al., 1997). Typha and Scirpus, or a combination of the two, are the most prevalent wetland vegetation types in the United States, with Phragmites dominating in European systems (Cooper and Green, 1995; Cole, 1998). Floating-leaved aquatic macrophytes such as Lemna (duckweed) and Eichhornia (hyacinth) are often used in constructed wetlands because they have rapid growth rates and can be easily harvested (Karpiscak et al., 1994; Sharma and Gaur, 1995). Submergent aquatic macrophytes have not been extensively used for wastewater treatment (Karpiscak, 1999). In choosing vegetation for a constructed wetland system, it is important to select species that are efficient at nutrient and contaminant removal, and those that are the least sensitive to phytotoxicity. Artificial wetlands are constructed with a great degree of control, experimental treatment facilities may vary the substrate composition, vegetation type, flow patterns, wastewater type and loading rates to obtain effluents having advanced secondary treatment quality (Brix and Schierup, 1989). In addition to wastewater treatment, 13 I. Emergent Aquatic Macrophytes Scirpus (bulrush) Typha (cattail) II. Floating-leaved Aquatic Macrophytes -1-117rtrir . 1 • • •••,• • '.' Eichhornia (hyacinth) Nymphaea (water lily) . ' • • • • . , . ,• • • • •'• • • Lemna (duckweed) III. Submerged Aquatic Macrophytes Potamogeton (pondweed) Littorella (shoreweed) Figure 1: Life forms of aquatic macrophytes commonly used in constructed wetland systems (Brix and Schierup, 1989) 14 constructed wetlands are thought to improve the landscape and provide habitats for a variety of wildlife, while treated wastewater can be used to irrigate parks and golf courses (Greenway and Simpson, 1996). As an inexpensive, low-maintenance technology, constructed wetland systems are increasingly being considered a treatment option for various wastewater problems. Environmental Factors Affecting Elemental Accumulation The most critical environmental factors controlling elemental uptake by macrophytes are concentration and chemical speciation within sediments and the water column (Van der Werff, 1981; Alloway, 1995). Elements are present in a wide range of chemical forms in sediments and the aqueous environment, in both dissolved and particulate phases (Morrison, 1990). Dissolved chemical species include hydrated ions and inorganic and organic complexes, while particulate phases include heterogeneous colloids and organometallic compounds (Langmuir, 1997). Major chemical forms of trace elements in soil solutions and aqueous environments are listed in Table 1. Elements dissolved in the form of free ion species are the most readily taken up by plants, although weak-ion and lipid-soluble complexes can also be highly bioavailable (Jones et al., 1991; Phillips, 1995). In aquatic environments, many variables determine chemical speciation and solubility, including pH, redox potential and the formation of insoluble metal complexes. Concentrations of dissolved elemental species are inversely related to pH, especially for the elements aluminum, cadmium, iron, manganese, lead and zinc (Albers and ▪ • •' 15 bo 0. . < to 4,- ,. C -,r1) + cl 1) *e on d) 1-1 V Ar 4-4 + rn .1) ,, 9 .-<4 , 0 ,-=', 0 0 , cn C.) Z >1 7=S C3' ° C.) O r9 C..) ., cn .:,-' A A cn +0 0 o (-) ' -'s O b c: A 0 0 .15' a.) +.1- ^ WI 4. + 1 ? 4 4:) p.., 0 .. •"' CJ C.) ci) + 0 4. j 0 ± A + " 4., ra., O 4 C..) N + 4-4 Z +0 <ril 0 6 .,.., 4c..)(1-3+- z r1_, P A N' L.) N 0 ôn l u (..) — + - `sz < z 0 i.., ± .' U o 0 o m .-, ''-' dr c),. (-4 - u tz" o cn ± + 0' co) .__, < c'-'0 (5 N < x u u u u Z .•••••n 0 6' C .) C 0 . + ' ,,, ,.. 0 4. a, \ C.) • . -2 § • 17. •— d rf)) 1§ • ▪ 0 "F•d O e_., ;•••I (1) t=1 0.1 0 0 U U C • U 4 71 tif) 0 ci • v. I) CI) v N 16 Camardese, 1993a,b). A decrease in pH effectively increases the concentration of free ions, and thus greater metal absorption by plants. Aquatic systems that are subject to acid deposition, and those which are poorly buffered are the most sensitive to the effects of pH on metal speciation (Van der Werff, 1981). Redox state determines the chemical form of an element, and thus its behavior in the environment. Hydric soils and a high organic content, both characteristic of wetlands, limit oxygen availability and push a system towards reduced conditions (Langmuir, 1997). Reduction occurs by both chemical oxidation and biochemical oxygen depletion from microbial respiration. Nitrate is the first soil component reduced (NO3 - -->NO2") followed closely by manganic manganese (Mn 4+ --->Mn2+) (Vymazal, 1995). Reductions of oxygen, nitrate and manganese may occur simultaneously, although subsequent reductions of iron, sulfate and carbon dioxide will not occur unless the preceding element has been completely reduced (Vymazal, 1995). Ferric iron is reduced to ferrous iron (Fe3± —>Fe2+) the predominant form in wetlands, which is the most soluble form and readily available to plants. In its reduced form, iron causes a bluish-gray coloration of soils, indicative of low redox potential (Vymazal, 1995). After iron reduction, sulfate is reduced to sulfide (SO4 2- ->S 2-) a process that gives waterlogged soils a characteristic rotten-egg smell. Sulfate acts as a terminal electron acceptor for many metals, including cadmium, chromium, cobalt, copper, lead, mercury, nickel and zinc, forming insoluble metal-sulfide compounds (Chino, 1981; Vymazal, 1995; DeLaune et al., 1998). Carbon dioxide reduction to methane (CO2--->CH4) also occurs under reduced conditions, usually when sulfate is present at low concentrations (Vymazal, 1995). Like iron, arsenic and 17 manganese become more bioavailable under reduced conditions, due to redox species changes (Chino, 1981). Depth of the aquatic macrophyte root system is an important factor affecting elemental accumulation, as root tissues may inhabit the oxidative surface layer or penetrate into the reductive subsurface layer. Physiological Factors Affecting Elemental Accumulation The most significant physiological process controlling macrophytic accumulation of nutrients and heavy metals is transport across biological membranes (Kabata-Pendias and Pendias, 1992). Root uptake and translocation require specialized transport mechanisms that depend strongly on chemical speciation. Elemental absorption occurs by three major transport routes, passive diffusion, carrier-mediated pathways involving membrane components, and active transport driven by a potential gradient (Morrison, 1990; Alloway, 1995). Physiological differences have been reported among species and among genotypes within species, with respect to elemental uptake sites and uptake mechanisms (Outridge and Noller, 1991; Kabata-Pendias and Pendias, 1992). Other physiological factors reported to affect elemental accumulation include ion interactions at the root surface, microbial activity, metabolic requirements, tissue storage capacity, maintenance of osmotic potential, surface area of the root, formation of root plaques and various root exudates (Outridge and Noller, 1991; Alloway, 1995; Phillips, 1995; Ye et al., 1997a,b,c). 18 Literature Review There is little information available concerning the levels of nutrients and heavy metals in the tissues of wetland macrophytes under normal growing conditions. However, data published on the elemental contents of terrestrial and freshwater plant species growing in uncontaminated environments can be analogous, and are somewhat useful for comparison purposes. Trace element data from the tissues of wetland macrophytes found in constructed wetlands and polluted environments are also discussed here. Outridge and Noller (1991) reviewed the published data discussing concentrations of trace elements in the tissues of freshwater vascular plants from uncontaminated environments. Their survey included wetland macrophytes and trace elements of interest to the current study, a summary of the data presented in their review article is listed in Table 2. They found that manganese had the highest concentrations reported in the literature for freshwater plants, followed by zinc, molybdenum, copper and lead. Higher concentrations of gold, arsenic, cadmium, chromium, mercury, nickel, lead, selenium and uranium were reported in freshwater plants than those reported for terrestrial vegetation. Concentrations of cobalt, copper, manganese and vanadium were similar in freshwater and terrestrial plants, and the concentration of zinc was observed to be lower in freshwater plants. Outridge and Noller (1991) also report that submergent and/or emergent species had been found to have higher concentrations of arsenic, cadmium, chromium, cobalt, lead, manganese, molybdenum, nickel, uranium and zinc than other plant life forms, while floating-leaved species had the lowest concentrations of 19 Table 2: Summary of trace metal concentrations in freshwater plants from uncontaminated environments (Outridge and Noller, 1991) Element n Ag As Cd Co Cr Cu Hg Mn Mo Ni Pb Se 16 22 64 25 58 70 16 77 35 56 64 14 7 16 67 U V Zn Minimum' Maximum 0.05 0.04 0.00 0.04 0.12 0.14 0.02 34 0.14 0.85 0.30 0.10 0.05 0.28 11 1.2 15 11 17 45 55 19 6,880 87 23 35 2.5 1.1 57 250 Median Mean Std Dey 95%C.L. 2 0.15 2.7 1.0 0.32 4.0 7.9 0.50 370 12 4.2 6.1 1.0 0.50 3.6 52 0.36 3.2 1.9 3.4 5.4 13 4.1 730 18 6.2 8.1 1.1 0.45 9.1 66 0.39 3.8 2.4 4.9 7.1 13 5.7 1,130 22 5.0 7.2 1.0 0.42 15 48 0.15-0.57 1.5-4.9 1.3-2.5 1.4-5.4 3.6-7.3 9.7-16 1.3-6.9 480-990 11-26 4.9-7.6 6.3-9.9 0.5-1.6 0.06-0.84 1.0-17 54-78 'Units in ug/g dry weight Confidence limits 2 elements except for copper. Root tissues were found to contain higher concentrations of most elements compared to aboveground plant parts, with the exception of manganese which was found at higher concentrations in leaves and stems. Finally, Outridge and Noller (1991) wrote that the maximum concentrations of trace elements in freshwater macrophytes from polluted environments were one to two orders of magnitude higher than levels which were determined to be naturally occurring. Kabata-Pendias and Pendias (1992) have conducted an extensive review of the published literature concerning concentrations of trace elements in soils and terrestrial plants. Table 3 lists approximate concentrations of trace elements found in mature leaf tissues, generalized for various terrestrial species. The chemical and biological 20 Table 3: Approximate concentrations of trace elements in mature leaf tissue generalized for various species (Kabata-Pendias and Pendias, 1992) Element Deficient' Sufficient or Normal Ag As B Ba Be Cd Co Cr Cu 5-30 2-5 F Hg Li Mn Mo Ni Pb Se Sn Sb Ti Ti 10-30 0.1-0.3 - 3 30-300 0.2-5 0.1-5 5-10 0.01-2 - 7-50 V Zn Zr l 0.5 1-1.7 10-100 <1-7 0.05-0.2 0.02-1 0.1-0.5 5-30 5-30 10-20 - 0.2-1.5 27-150 - Excessive or Toxic 5-10 5-20 50-200 500 10-50 5-30 15-50 5-30 20-100 50-500 1-3 5-50 400-1,000 10-50 10-100 30-300 5-30 60 150 50-200 20 5-10 100-400 15 Tolerable in Agronomic Crops 100 3 5 2 50 300 50 10 300 Units in ug/g dry weight properties of nutrients and trace elements discussed by Kabata-Pendias and Pendias are relevant to the present study. They report that aluminum is an essential element for all plants, occurring in crops in the range 10-900 ug/g, with aluminum-accumulating species containing more than1,000 ug/g. Arsenic concentrations of crops grown on uncontaminated soils are reported to be between 1-1.7 ug/g, with 5-20 ug/g being excessive or toxic. Cadmium is a non-essential element for plants, although it is 21 absorbed by plant roots and leaves. Normal cadmium concentrations in plants range from 0.05-2.0 ug/g. Most soils contain significant amounts of chromium, although plant availability is highly limited, common levels of chromium in plants are reported to be 0.1-0.5 ug/g. Cobalt is not known to be an essential element for higher plants, although there are several reports of the beneficial effects of cobalt on nitrogen fixation. Normal cobalt concentrations in plants range from 0.02-1.0 ug/g, with 15-50 ug/g being excessive or toxic. Copper sufficiency in plants is reported to be 5-30 ug/g, with toxicity at 20-100 ug/g. Plants have a strong tendency to hold copper in root tissues, limiting transport under conditions of deficiency or excess. Shoot tissues usually do not exceed 20 ug/g copper in species growing under natural conditions, this value is often considered to indicate the threshold of excessive content. Natural iron concentrations in plants range from 18-1,000 ug/g, depending on the solubility of iron in the soil. Lead occurs in all higher plants due to environmental pollution, although it is a non-essential element. Normal lead concentrations in plants are reported to be 5-10 ug/g. Natural levels of lead in plants growing in uncontaminated areas are quite constant, ranging from 0.1-10 ug/g with a mean of 2 ug/g. A wide range of manganese has been reported in plant tissues, with normal ranges being between 30-300 ug/g. The critical manganese deficiency level for most plants is 10-30 ug/g, while toxic concentrations of manganese are more variable depending on plant and soil factors. Normal nickel content of plants growing on uncontaminated soils are reported to be between 0.1-5 ug/g. Environmental pollution greatly influences plant concentrations of nickel, tops of plants accumulate nickel in areas where it is airborne. The essentiality of selenium in plants is still unknown, although 22 plant concentrations have been actively investigated because of selenium's role as both a micronutrient and a toxin in animal and human nutrition. Normal selenium ranges are reported to be between 0.01-2 ug/g, with 5-30 ug/g being excessive or toxic. Zinc concentrations in plants are related to soluble forms available in the soil, and are greatly influenced by environmental zinc pollution. Normal levels of zinc in plant tissues range from 27-150 ug/g, with excessive or toxic levels being between 100-400 ug/g (Kabata- Pendias and Pendias, 1992). Markert (1994) published trace element contents of a "reference plant", which are considered to be representative of trace element concentrations for plants in general (Table 4). Markert's reference plant data is in good agreement with the terrestrial plant data reported by Kabata-Pendias and Pendias (1992). Table 4: Trace element content of a "reference plant" (Markert, 1994) Trace Element Aluminum (Al) Antimony (Sb) Arsenic (As) Barium (Ba) Beryllium (Be) Bismuth (Bi) Boron (B) Bromine (Br) Cadmium (Cd) Cerium (Ce) Cesium (Cs) Chromium (Cr) Cobalt (Co) Copper (Cu) Fluorine (F) Gallium (Ga) Gold (Au) ug/g 80 0.1 0.1 40 0.001 0.01 40 4.0 0.05 0.5 0.2 1.5 0.2 10 2.0 0.1 0.001 Trace Element ug/g Iodine (I) Iron (Fe) Lead (Pb) Manganese (Mn) Mercury (Hg) Molybdenum (Mo) Nickel (Ni) Selenium (Se) Silver (Ag) Strontium (Sr) Thallium (Tl) Tin (Sn) Titanium (Ti) Tungsten (W) Uranium (U) Vanadium (V) Zinc (Zn) 3.0 150 1.0 200 0.1 0.5 1.5 0.02 0.2 50 0.05 0.2 5.0 0.2 0.01 0.5 50 23 Karpiscak et al. (1997, 1998) report concentrations of nutrients and heavy metals in the tissues of wetland macrophytes grown in constructed wetland treatment systems at the Constructed Ecosystems Research Facility (CERF). CERF is a joint project of the Pima County Wastewater Management Department and The University of Arizona's Office of Arid Lands Studies, and is comprised of parallel subsurface constructed wetland systems. The experimental wetlands are planted with identical macrophyte species and receive either potable water or unchlorinated secondary quality municipal effluent. Average annual nutrient and heavy metal concentrations are reported for the tissues of Anemopsis californica, Arundo donax, Baccharis, Fraxinus sp., Populus fremontii, Salix nigra, Scirpus olneyi and Typha domingensis for samplings throughout 1995 and 1996 (Table 5). Karpiscak et al. (1997, 1998) report elemental concentrations in leaf, root and flower tissues separately for Anemopsis californica, Scirpus olneyi and Typha dom ingensis (Table 6). Karpiscak et al. (1997, 1998) report that the concentrations of total nitrogen, phosphorous, sodium, manganese and chloride were higher in plants sampled from the effluent-fed wetland system than from the potable-fed system. Zinc and copper concentrations were generally greater in plants sampled from the potable-fed system, with the exception of Anemopsis. Lead was detected at about the same concentration in both water systems, except for Anemopsis, which concentrated lead in the effluent-fed system. Nitrate and iron concentrations were approximately the same in plant samples from both systems, and there was no consistency reported with regard to the concentrations of total potassium and boron and wetland treatment system. 24 Table 5: Selected chemical parameters in plant tissue samples from potable and effluent-fed constructed wetland treatment systems (Karpiscak et al., 1997, 1998) Salbc nigra Populus fremontii Fraxinus sp. Anemopsis californica Nitrogen Phosphorous Potassium Chloride Nitrate Sodium Iron Zinc Copper Lead Manganese Boron Nitrogen Phosphorous Potassium Chloride Nitrate Sodium Iron Zinc Copper Lead Manganese Boron Nitrogen Phosphorous Potassium Chloride Nitrate Sodium Iron Zinc Copper Lead Manganese Boron Nitrogen Phosphorous Potassium Chloride Nitrate Sodium Iron Zinc Copper Lead Manganese Boron % ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g % ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g 1995 Average Concentration Potable System Effluent System 2.37 3.21 0.19 0.33 1.48 1.38 723 683 60.8 60.0 299 647 95.0 82.3 57.1 29.1 12.8 7.43 <1.25 <1.25 136 1,039 62.4 48.2 1.78 2.59 0.12 0.38 1.43 1.50 248 330 86.8 71.7 355 1,014 55.4 55.7 55.4 23.6 10.0 4.53 <1.25 <1.25 126 201 51.1 53.6 % ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g % ug/g ug/g ug/g ug/g ug/g ug/g uglg ug/g ug/g No data available, plants not mature. 2.11 0.14 3.70 30,329 1,061 3,080 110 15.6 6.98 1.56 44.3 60.3 4.14 0.43 4.80 38,900 1,371 6,660 135 21.1 6.18 4.86 163 55.9 1996 Average Concentration Potable System Effluent System 1.86 3.39 0.10 0.27 1.68 1.59 930 970 <30 32.7 87.8 1,602 158 186 85.5 21.8 9.88 4.97 1.67 2.48 411 857 76.6 54.3 1.87 3.11 0.12 0.41 1.55 1.86 174 524 <30 10.8 269 1,809 133 125 61.9 14.4 7.51 2.45 <5.1 <5.1 148 222 50.6 68.8 0.71 0.88 0.05 0.08 0.57 0.50 239 220 25.0 50.5 <60 <60 60.2 63.3 9.37 5.63 4.97 2.41 <5.1 1.14 14.2 19.5 16.5 19.4 1.90 4.11 0.11 0.46 3.79 4.88 36,160 40,840 186 2,132 7,558 11,824 205 492 17.4 16.3 7.33 4.49 1.38 1.59 63.5 202 61.0 76.9 25 Table 5: Continued Arundo donctx Nitrogen Phosphorous % Potassium Chloride Nitrate Sodium Iron Zinc Scirpus olneyi Copper Lead Manganese Boron Nitrogen Phosphorous ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g % Potassium Chloride Nitrate Sodium Iron Zinc Typha domingensis Copper Lead Manganese Boron Nitrogen Phosphorous ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g % Potassium Chloride Nitrate Sodium Iron Zinc Baccha ris Copper Lead Manganese Boron Nitrogen Phosphorous ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g % Potassium Chloride Nitrate Sodium Iron Zinc Copper Lead Manganese Boron ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g ug/g 1995 Average Concentration Potable System Effluent System 2.24 3.03 0.15 0.29 1.87 2.16 6,943 6,941 296 247 253 265 152 110 21.0 19.3 10.5 4.18 8.74 6.13 62.1 112 14.0 22.3 2.21 2.72 0.13 0.25 1.83 1.46 19,729 24,179 105 138 4,131 4,168 83.3 96.9 25.7 22.0 7.81 4.98 <1.25 <1.25 377 1,962 135 115 2.42 2.95 0.15 0.26 1.82 2.11 19,764 19,664 104 116 2,884 3,984 63.1 61.8 14.4 17.9 4.18 9.80 1.44 1.58 273 834 95.4 160 2.06 3.09 0.21 0.46 2.64 2.33 10,180 9,713 362 383 1,376 3,195 96.0 95.7 21.0 32.7 4.54 11.1 2.72 2.36 108 68.7 48.7 75.0 1996 Average Concentration Potable System Effluent System 1.80 2.81 0.13 0.24 1.51 2.04 6,406 8,136 125 177 16.0 <60 191 168 15.8 13.0 9.18 7.30 5.45 3.01 179 175 19.8 23.5 2.25 2.98 0.15 0.24 1.54 1.96 16,600 23,680 34.9 47.0 2,974 5,404 155 176 19.2 18.2 7.89 4.80 <5.1 <5.1 702 1,728 131 131 2.43 2.91 0.28 0.15 2.24 2.58 18,540 23,000 47.4 49.8 3,362 4,933 222 146 17.1 14.9 9.12 3.90 2.57 1.29 345 1,075 202 136 2.18 3.34 0.52 0.22 2.61 2.37 9,388 10,392 35.0 242 1,690 3,987 232 429 48.3 20.2 11.2 3.99 <5.1 <5.1 104 106 41.5 62.8 • • m 26 sc E s M ,r, as 0, •-• C ,.,-, P:0' '''' a n m ,--n' CI) en P4 cii .-. 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'cr>.; C,'1 " g°, ” a" % ''R •-• 6 'I" 4".. °^9 a ..7 = C'i s'f,'-:. V I 00 til) 00 Ob 00 60 013 01:1 0.0 e ' c ' --el -a) --a) 'a) '-a) -a) -a) -a) -a) 00 00 0.0 GO 00 00 00 00 00 ,e' e' a) a) a) a) a. a) 'a) sa) ' a) 000=DDDDD aDDDDDDDD - - - - -- - - 1 §g 0., ts t `S . g) f.. ..t 72 2 g 11:2 2 § .e 8 S 2 11 ;.5 = ,, R. "gi g 2 B 8 'A .2 g 4,- 0 2 E.. li e g . .r.: d 'A' 4 e. i. (5 2 2 '9 i&1 d A' 4 e, 4 (5 r2 ..? ° § °.' 0 2 24i - - E 03 D . cr c, co E4 Il tn . . O N al O O `D h so 00 61) 00 000000 01:1 00 00 00 k`,'s-a) --an 77 7 77 D 7 7 c .5.2 -"C rn Ca ,.... ''D ,ri Fei re;- ',;: ":' V g re-i go l'h § C,A.Egv,9 e. d "2' c?) 27 Anernopsis was reported by Karpiscak et al. (1997, 1998) to have the highest concentrations of most of the chemical parameters studied. Vymazal (1995) surveyed the literature for concentrations of macronutrients, micronutrients and trace elements in algae and aquatic and wetland plants. Wetland plants surveyed by Vymazal included emergent, submergent and floating species, and many are divided into above and below ground tissues (Table 7). Data presented by Vymazal are from uncontaminated and contaminated wetland environments, and values are greater than those reported elsewhere. Table 7: Elemental concentrations in emergent, submerged and floating-leaved life forms of aquatic and wetland plants (Vymazal, 1995) Element Tissue Emergent Species' Arsenic Boron AG2 AG AG BG3 AG AG AG BG AG BG AG BG AG BG AG BG AG AG BG AG BG 0.04-12 1.2-100 0.02-11 0.1-16 <1.0-17.2 0.01-6.72 <1-1,900 1.3-81 19-59,000 42-6,900 0.04-657 <0.1-88 13-5,400 13-365 <0.01-2.2 0.01-1.47 <1.0-1,200 0-280 0-52.3 1-337 20-440 Cadmium Chromium Cobalt Copper h-on Lead Manganese Mercury Nickel Selenium Zinc 'Units in ug/g dry weight plant tissue 3 Belowground plant tissue 2Aboveground Submerged Species Floating Species 0.33-3,700 0.47-959 0.1-32.3 0.5-30 1.06-2,567 5-10,600 0.86-122.2 <1-36.1 3-206 0.27-8,600 0.33-18.6 0-54,500 80-110,000 50-8,440 0.8-7,750 2.7-25,790 73-17,100 400-13,000 <0.01-26.4 0.01-3.8 4-87.3 4-33.9 11.5-650 24-3,224 28 CHAPTER 2: RESEARCH OVERVIEW This research determined concentration ranges at which micronutrients and heavy metals naturally exist in the tissues of wetland macrophytes in Arizona. Furthermore, elemental distributions within the plant root, shoot and leaf parts were measured. Background data are necessary for evaluating the degree to which nutrients and heavy metals can be concentrated in constructed wetland systems. Knowledge of background concentrations will enable us to better understand the effectiveness of engineered wetlands, and the impact such systems have on our environment. Site Selection Seven naturally occurring wetland sites were selected for this research: Empire Cienega, Canelo Hills Cienega, Patagonia-Sonoita Creek Preserve, Cook's Lake, St. David Cienega, Bingham Cienega and Agua Caliente Park. Sites chosen for this research have been classified as natural wetland systems, and most of the plant species selected for analysis are found at each. These sites are owned and managed by The Nature Conservancy, The Bureau of Land Management or The Bureau of Reclamation, as outlined in Table 8. Locations of the selected wetlands in the state of Arizona are illustrated in Figure 2. Maps detailing directions to the study sites and sampling points within each site can be found in the appendices. Empire Cienega is a Resource-Conservation riparian area and marshland located on the Cienega Creek. Dominant vegetation includes Populus fremontii and Salix gooddingii, both mature and seedling plants, as well as Typha domingensis, Scirpus 29 Table 8: Selected sites, wetland types and ownership Site: Empire Cienega Wetland: Cienega Owner: The Nature Conservancy Contact: Dave Gori, (520) 622-3861 Site: Canelo Hills Cienega Wetland: Cienega Owner: The Nature Conservancy Contact: Jeffrey Cooper, (520) 394-2400 Site: Patagonia-Sonoita Creek Preserve Wetland: Cienega Owner: The Nature Conservancy Contact: Jeffrey Cooper, (520) 394-2400 Site: Cook's Lake Wetland: Wooded swamp, Cattail marsh Owner: U.S. Bureau of Reclamation Contact: Diane Laush, (602) 395-5694 Site: St. David Cienega Wetland: Cattail marsh Owner: U.S. Bureau of Land Management Contact: Karen Simms, (520) 722-4289 Site: Bingham Cienega Wetland: Wooded swamp, Cattail marsh Owner: Pima County Flood Control District, managed by TNC Contact: Dave Gori, (520) 622-3861 Site: Agua Caliente Park Wetland: Developed Cienega Owner: Pima County Contact: Evelyn Thorpe, (520) 740-2690 30 31 acutus and Sporobolus sp. Plant communities in this area are classified as ScrubGrassland (143.1), Sonoran Riparian and Oasis Forests (224.5) and Sonoran Interior Marshland (244.7) using the classification system devised by Brown et al. (1979) and Minckley and Brown (1982). Canelo Hills Cienega is located on a small tributary of the Babocomari River, feeding off of the San Pedro River. A concrete structure at this cienega has created a permanent pool of water, with predominant vegetation including Prosopis velutina, Populus fremontii, Salix gooddingii and Scirpus arnericanus. Plant communities include Sonoran Riparian and Oasis Forests (224.5) and Sonoran Interior Marshland (244.7). Patagonia-Sonoita Creek Preserve is a riparian habitat with remnant cienegas, located in the floodplain valley between the Patagonia and Santa Rita mountains. The dominant vegetation type within this habitat is the Populus fremontii-Salix gooddingii association, with prominent low-growing Anemopsis californica. The plant communities at Patagonia-Sonoita Creek Preserve are classified as Sonoran Riparian and Oasis Forests (224.5) and Sonoran Interior Marshland (244.7). Cook's Lake, a 32 acre conservation area located 400 meters east of the San Pedro River, is classified as a spring-fed riparian woodland and marsh. A vegetation analysis was conducted for Cook's Lake that identified 235 plant species and 11 plant associations (Baker and Wright, 1996). The dominant vegetation type within the riparian woodland and marsh is Salix gooddingii, with prominent associations including Larrea tridentata, Fraxinus velutina , Scirpus acutus, Prosopis velutina, Tamarix ramosissima, Populus fremontii, Cephalanthus occidentalis, Scirpus americanus and Typha domingensis. 32 Baker and Wright divided the communities into dry, Sonoran Desertscrub (154.1), wet, Interior Southwestern Deciduous Forests and Woodland (223.2), Sonoran Riparian and Oasis Forests (224.5), Interior Southwestern Swamp and Riparian Scrub (233.2), Sonoran Interior Strand (254.7) and Sonoran Interior Marshland (244.7). St. David Cienega is a cattail marsh and mesquite bosque located near the San Pedro River. Typha domingensis is the dominant plant species in this protected area, with prominent Prosopis velutina. Classification of the biotic communities within St. David includes Sonoran Riparian and Oasis Forests (224.5) and Sonoran Interior Marshland (244.7). Bingham Cienega is a wooded swamp and cattail marsh located in the San Pedro River Valley. This area is heavily vegetated by Prosopis juliflora, Baccharis glutinosa and Sporobolus airoides, with the wetland being dominated by Typha domingensis and Lemna spp. Plant communities in this area include Scrub-Grassland (143.1), dry, Sonoran Desertscrub (154.1), Sonoran Riparian and Oasis Forests (224.5), Sonoran Interior Marshland (244.7) and Sonoran Inland Submergents (264.7). Agua Caliente Park, located northeast of Tucson, is a 101-acre aquatic/riparian habitat surrounded by the Sonoran Desert. A spring feeds three ponds within Agua Caliente Park, linked to each other by an artificial stream. Vegetation at this park includes Prosopis velutina, Populus fremontii and Salix gooddingii, classified as a Sonoran Riparian and Oasis Forest (224.5) community, and Scirpus acutus, Typha domingensis and Anemopsis californica, classified as a Sonoran Interior Marshland (244.7) community. 33 Plant Species Selection Plants selected for this research are species that are commonly used in constructed wetland systems, or planted nearby, and are identified on the "National List of Plant Species that Occur in Wetlands" (Reed, 1988). Selected species include Anemopsis californica (Nutt.) Hook. & Arn. (yerba mansa), Fraxinus velutina (Torr.) (velvet ash), Lemna spp. (Phil.) (duckweed), Populus fremontii (Wats.) (Fremont cottonwood), Salix gooddingii (Ball) (Goodding black willow), Salix lasiolepis (Benth.) (Arroyo willow), Scirpus acutus (Muhl.) Ex Bigelow (hard-stem bulrush), Scirpus americanus (Pers.) (three-square bulrush) and Typha domingensis (Pers.) (southern cattail). Reed et al. (1988) have developed a system of categories for assessing the occurrence of plants in wetland environments, as outlined in Table 9. Obligative wetland plants almost always occur in wetlands, with a probability of greater than 99 percent, and facultative wetland plants are usually found in wetlands, with a probability of 67-99 percent. A "+" or "—" is often applied to the categories to indicate that the species is found at the higher or lower end of the probabilities. With the exception of Fraxinus, all of the species included in this study are categorized as either obligative or facultative wetland plants (Table 10). Elemental Analysis Elements selected for analysis in this study are micronutrients and heavy metals that are prevalent in wastewater and can be toxic to plants and animals at elevated levels. Soil, water and plant tissues were sampled and analyzed for aluminum, arsenic, cadmium, 34 Table 9: System of categories for determining the occurrence of wetland plants (Reed et al., 1988b) Category Occurrence in Wetland Environment OBL Obligative Wetland Plant > 99% of the time FACW Facultative Wetland Plant 67-99% of the time FAC Facultative Plant 34-66% of the time FACU Facultative Upland Plant <33% of the time UPL Upland Plant almost never Table 10: Selected plant species and their wetland categories (Reed et al., 1988; Baker and Wright, 1996) Scientific Name A nemopsis californica Fraxinus velutina Lemna spp Populus fremontii Salix gooddingii Salix lasiolepis Scirpus acutus Fremont cottonwood Scirpus americanus Typha domingensis Common Name yerba mansa velvet ash duckweed Wetland Category OBL FAC+ OBL Goodding black willow arroyo willow hard-stem bulrush three-square bulrush southern cattail FACW OBL FACW OBL OBL OBL 35 chromium, cobalt, copper, iron, lead, manganese, nickel, selenium and zinc. The term nutrient describes an essential element which is "required by an organism to build living tissue and maintain the chemical reactions of the life process" (Pais and Jones, 1997). Macronutrients are essential elements that an organism needs in relatively large quantities, and micronutrients are needed in relatively small quantities. The term trace element is used for non-essential elements that are found at low concentrations in plant tissues. Heavy metal is a term referring to the metal trace elements, generally describing metallic elements with high atomic weights and similar health effects. Pais and Jones (1997) have stated that the heavy metal group is "somewhat poorly defined" with a range down to atomic weight 24 (chromium), and includes several non-metals such as arsenic and selenium. Table 11 lists the form, classification and biological functions of the elements selected for analysis in this study. Data Analysis Concentrations of 12 elements have been determined in the tissues of nine wetland macrophyte species, sampled from seven study sites. Data analysis was done by element, with separate sections used to discuss the concentration ranges, means and 95% confidence limits for each element in the tissues of selected plant species. Data is reported below a minimum detection limit for samples with no nutrient and heavy metal concentrations detectable. For statistical analysis, values below the minimum detection limit are assumed to be halfway between zero and the minimum detection limit, assuming these values are normally distributed (Bilisoly et al., 1997; Clarke, 1998). 36 Table 11: Selected elements and their form, classification and biological functions (Modified from Pais and Jones, 1997) Element Form Classification Biological Function Aluminum metal trace element Control of colloidal properties in the cell Arsenic non-metal trace element Metabolism of carbohydrates Cadmium metal trace element None Chromium metal trace element None Cobalt metal trace element Combines with proteins and enzymes for catalytic properties Copper metal micronutrient Oxidation, photosynthesis and metabolism of proteins Iron metal micronutrient Photosynthesis, nitrogen fixation and protein and dehydrogenase • constituent None Lead metal Manganese metal trace element micronutrient Nickel metal micronutrient Hydrogenase reactant and nitrogen translocation Selenium non-metal trace element Combines with proteins and enzymes for catalytic properties Zinc metal micronutrient Metabolism of carbohydrates and proteins Photoproduction of oxygen and nitrate reduction 37 Coefficient of variability (C.V.), number of samples (n) and percent censored data are also reported for each element. A complete plant data set listing plant samples by study site can be found in the appendices. Plant analysis was done by plant part, and data are reported separately for root, shoot and leaf tissues. Plant life forms are also included, referring to the structure of the species, with terrestrial herb (H), tree (T), shrub (S), free-floating floating-leaved (F) and rooted emergent (E) macrophyte species. For discussion, plants are often grouped by plant part and life form. Soil and water samples were collected at the same sampling points, and are also discussed with the plant data. 38 CHAPTER 3: METHODS AND TECHNIQUES Sample Collection Soil, water and plant tissue samples were collected at seven natural wetland sites during May 1998, as outlined in Table 12. Three sampling points were selected within each site where standing water was present, and soil and water grab samples were collected at these sampling points. Plant tissue samples were collected within a fivemeter radius of the soil and water sampling points at each site. At the Patagonia-Sonoita Creek Preserve and St. David Cienega wetland sites, only two sampling points were selected due to insufficient plant growth. Agua Caliente Park was treated as one sampling point because plants were found in clusters by species throughout the park. Table 12: Sampling schedule. Site Sampling Date Empire Cienega May 13, 1998 Canelo Hills Cienega May 14, 1998 Patagonia-Sonoita Creek Preserve May 14, 1998 Cook's Lake May 15, 1998 St. David Cienega May 19, 1998 Bingham Cienega May 23, 1998 Agua Caliente Park May 23, 1998 39 A trowel was used to collect the top 10 cm of soil at each sampling point. In places where a layer of peat was covering the soil, the peat was removed and the soil sample was taken from below the peat material. Soil samples were placed in Ziplock bags and then in an ice chest for transporting. Water samples were collected in 500 mL, acid-rinsed Nalgene bottles and placed in an ice chest for transporting. A Horiba U-10 water quality meter was used to determine the temperature, pH and electrical conductivity (EC) of the ambient water at each sampling point. Plant tissue samples were collected in three aliquots around each sampling point, and then composited to represent that point. Root samples were dug from the soil using a trowel, and rinsed in the field with deionized water. Shoot samples were cut at a height of 2 cm above the soil surface with clippers. Leaf samples were collected by clipping clusters of leaves throughout three trees near the designated sampling points. Plant samples were placed in paper bags for transport to the laboratory. A specimen of the plant species sampled at each site was preserved in a field press, and later identified at the University of Arizona herbarium. Table 13 indicates the presence of the selected plant species at each of the seven study sites. Sample Preparation In the laboratory, soil samples were spread out on trays and air-dried, then passed through a 2 mm sieve. Residual plant material was removed from the soil samples during the sieving process. Soil samples were then acid digested using concentrated, 40 kkkk 41 trace-metals grade nitric acid in a CEM closed-vessel microwave oven (EPA method 3051, modified). Microwave digestion procedures are advantageous because they reduce the loss of reagents and sample, and obtain a more complete oxidation of the sample material allowing for total metal determination (Greenberg et al., 1992). 5MA1 soil standards, sample duplicates and reagent blanks were included in each digestion batch to assure appropriate quality control. Acid digested samples were stored in 30 mL Nalgene bottles at room temperature. Water samples were filtered in the laboratory with #1 Whatman filter paper, then acidified with concentrated, trace-metals grade nitric acid to a pH of less than 2. Samples were stored in 500 mL Nalgene bottles at room temperature. Filtration and acidification of water samples allows for the determination of dissolved metal species (Greenberg et al., 1992). Plant tissue samples were gently rinsed with deionized water in the laboratory, then placed in a drying oven at 60° C for 24 hours. Dried plant material was ground using a Wiley-mill fitted with a 40-mesh screen, and stored in coin envelopes in the drying oven. Ground plant material was acid digested using concentrated, trace-metals grade nitric acid and hydrogen peroxide in a CEM closed-vessel microwave oven (EPA method 3052, modified) in preparation for the determination of total metals. National Institute of Standards and Technology (NIST) pine needle and tomato leaf standards, sample duplicates, and reagent blanks were included in each digestion batch to assure appropriate quality control. 42 Sample Analysis Sample were analyzed for micronutrients and heavy metals at the Soil, Water and Plant Analysis Laboratory at the University of Arizona using a Leeman Labs UV1000 Inductively Coupled Plasma Optical Emission Spectrometer (ICP/OES). Further elemental analysis was done at the University of California, Riverside in the Department of Soil and Environmental Sciences. Instrumentation at the University of California, Riverside included a Perkin-Elmer 5000 Atomic Absorption Spectrometer (AAS) with hydride vapor generation, a Perkin-Elmer 3000DV Optima ICP/OES, and a VG PlasmaQuad 2 Inductively Coupled Plasma Mass Spectrometer (ICP/MS). Soil and plant tissue samples were analyzed for total concentrations of aluminum, iron and manganese at the University of Arizona and at the University of California, Riverside by ICP/OES (EPA method 6010B, modified), and good agreement was found between analysis at both universities. Concentrations of aluminum, iron and manganese observed in soil and plant samples are high, and easily detectable by optical emission spectrometry. ICP/MS was used to determine trace amounts of total arsenic, cadmium, chromium, cobalt, copper, nickel, lead and zinc in soil, plant tissue and water samples, and total aluminum, iron and manganese concentrations in water samples (EPA method 6020, modified). Selenium determination was done by conversion to the volatile hydride form by sodium borohydride, and aspiration into an AA (EPA method 7742, modified). 43 Minimum detection limits were determined for each element by analysis of 10 replicates of the lowest concentration calibration standard, then multiplying the standard deviation of the replicates by 10 (EPA method detection limit, modified). Quality control consisted of the analysis of National Institute of Standards and Technology (NIST) and SMA1 standards, analysis of reagent blanks, calibration with certified standards, and analysis of sample duplicates. Certified NIST standards, with concentrations near the sample levels, were analyzed at 10 percent of the total sample volume and maintained within 10 percent of the known values. Reagent blanks were analyzed at five percent of the total sample volume to monitor the purity of the reagents used, and serve as overall procedural blanks. Certified standards were used to calibrate the instruments daily. Sample duplicates were analyzed at five percent of the total sample volume, and were maintained within 10 percent of the known concentrations for precision. 44 CHAPTER 4: RESULTS AND DISCUSSION Aluminum The mean concentration of aluminum observed in naturally occurring wetland macrophytes in Arizona was 740 ug/g (Table 14). Anemopsis californica had the highest aluminum content of the plant species sampled in this study, with a mean concentration of 2,312 ug/g in the leaf tissues and 2,151 ug/g in the roots (Table 15). A high mean aluminum value for Anemopsis californica is due to a single specimen obtained from St. David Cienega, with an aluminum concentration of 11,660 ug/g. Lemna sp. and roots of the emergent macrophytes Scirpus acutus, Scirpus americanus and Typha domingensis also concentrated aluminum to a high degree, with ranges of 476-2,041 ug/g for Lemna sp. and 102-8,641 ug/g for the roots of the three emergent species. Emergent macrophytes concentrated aluminum up to ten times greater in root tissues than in shoot tissues, with mean concentrations of 1,238 ug/g in the roots and 217 ug/g in the shoots. Tree and shrub leaves contained the lowest levels of aluminum, with a concentration range of <64.4-304 ug/g. Aluminum concentrations in water samples were all below the minimum detection limit, 500 ug/L (Table 16). The EPA has established the Criteria Maximum Concentration (CMC) for total aluminum in surface water to be 750 ug/L to avoid harmful effects to aquatic organisms (EPA, 1998). Aluminum concentrations in water samples for this study are below levels recommended by the EPA. •o • 45 Q $1 - ,,, CD en VI 4.., CD k 0 N r) r•-, z cel N ,•:D VD "t 7t* 4.) a) (.....) v) (1.) 0 0 VI 00 CT \ N 00 kr) g':.'• En cn • ...4 +, O r0 N • 0 •,.-( ,-, ‘.0 %.0 en en 0'1 00 "1- ,-4 ,•1 00 00 N CT\ ,--( 0 kn cr) 0 VD 00 N n--4 ,---1 ,--i n—i n-••+ N cri r•-4 (..5 0 N fr) nnI '.0 a) cdc'' a) 0 cn . ,_, N CID . ., O •- . • O 0 - -d 0 --c 71- cp o, v=> .1- , .0 C •71" — NC 0 1/44D CD oo 01 irn N 0 N CD .q * -510 (I) .—• kr) N ,--4 'I' . N ,-C ,CR 4a' cr) 6 6 6 6 . N ,-- . N V:5 6 nc; a) P., o cll 0 ;7 71 F . , . . , . ± + +++++ -- --- -±-- ---11- -r --P -4-- L)..)1-4 , • 0 Q E C kr) -s 0.) E o o ke-) t--N ed en c:, N t--- -71- 0 71- ,--, 0 ct c)o, ,... kr1 c>en 0.n c) -71- ,c, cl) ,Z 0 N 6 6 ,--, c; kr; tr) c-,i N 00 6 . , I 1 -5 0 8 o o -1- en (r) --, k -5 —c7,e-) i4rt 0 v:).. kr) — N kr) o 1-, .-I O cd 0 m '7' 4;:i 1:4) N ci-.( 0 0 ,t1 ; 8 Z 00 cn 4 cr) ,--+ N VD 6 C; 0 0 V V V 4 0 z .1- 1 °61/44:, 6 ---" kr1 N 0 1.n 0 71- d' 6 'd). ,-, •1: V r l-) 14 ,••n o en ,--, 4. 4 en" N <:,ns 00 tl) , d- • N cz:, ,--, N. ,-..4 .--i cA ,--4 N d kr) co:, (.) 6 c,i 6 6 cNi V N V V V ,---4 kr) kr) •71- •• n n••••1 C c) C o c) C o o 0 0 0 0 r•-4 11 11 0 r0 03 E-4 +o-a)' 5 cu W oo (,) g 1 ••' • • E 6. E 0 E ..-. ,. , a) P., 0 -cVc3 0 ;-, .8 :71 o 7ct o v) c) o c) 49 -.T' -, •P 6 , , .." Cf) 0 to 5 (3.) o .. ,9 "<".1 °.)- ..`')-, LNJ I l 46 g 0 o rcd 1.4 0 0 0 0 cr) oc ce 'I' 'd: tan oo c. t1/4.0 (^fl N CD cf) N N 1/40 00 l -c a) t)t) tu E H 0 4 -cl CI) 0 g a0 a) rc1 cu cct cn ct -0 0 >. oc g1 0 0 po tr) 4-4fl en cn N N 1-1 /-I g c...) CL) 4-n CIO N C A 71' N N 1--- cn 00 ci-) 01 00 cs, N cr-1, 1/4.0 c), crc ocC 71: N 4-4 Ncr) 1 I I I ,-1 N 01 ,.-1 14-) ce) en ,..-1 Th 7r cl, ...-4 C'T N' '4-4 1 'Tt' -: %, , a \ I I 0 c) ci; r-I (7 \ I N (----00 1 00 o 00 I -:1CP% (71, 1..1 I I a) -0 ed 0 I N e„) . 1 .0a) 0 tu tu 4. t--- t--- Ir-N g:100 re) 00 v-.4 "cl 0 4 0 t s1 -0 0 g a) - a) ci; En 0 Fi 1-1 C. 777- tr) Ir)" I I c;1' 00 Cl cf) C, NN 4 N ' 71- \ (-V 71- 71- 00- c.!,1 4 4 4 n.r.) V V V s oc 00 r 4 ,c=1, nc) C71 cr) 71: 1/4.0 00 a.) -g 4 4 ,•-n Z oo v;) oo 7-1 -0 cd ca. cd .0 4 a) .0 0 7:1 .. N V0 ir) Lr) N 1/4.0C v-4 1-1 1--1 Cr) re") 4-1 1-1 g cd -0 a) 0 t a) tu C4 En i,'; 0 .-. c.) a) 10., cd a) 4. cd Cd 4-1 H E-n V) 4.1 W4 W;.T4 .... g .4.: .-.1 g 74 ' Cd /) ( 45 CD Ci) › C 0 1.) 41 0 0 0.) C) . P. . CI0.) • 1.4 €04 o o 44 -,.., • ,... ''' 0 ci) ,..: t'A" -,.. 0 O.) ''' ,;•. '.1-4 0) '-- ci) 4,t_.-..., cd SZL4 0 0 ' -.1/4 as "C! 0 p 40 . 0 Cn o ci) ci) 'te .,..> 0 &) 0 0 c.0 &) o-4 ;.. COD • .., o . *.k' .,... • .4 &) ci) ZI-1 Z-4 0 0 0) 0.) cf) ''` e) " P. . - . 0 • ,-1 4.4 0 C/) rn 0.) CS c...) Z Z •Z c)) •Z '4) 0) '&10 0 &) 0) 0 cd 0 cn 0 c..) QI ... •wa 0.) C• :1.1 4. •1•4 0.) C'' Q.4 ... • n••4 0) C' C44 o) 7IS . ..-tzl C') 4. • .4 Ce/ ci) -ic.) -t o 44 • &) 00 • 1,1 C.) a.) cu -0 a) .405 5 ,_ z 0 ci) ce) -g c.) IDA ,--. • Il .. E ' 0 ,',E C') cn •.., C/) ++ 01/40 . IV E 0 0 "0 '"0 p p ,-- .-Q-4 Z1/44 ?,,, ?•,, E -4 E---I 0 '1-• 0 di) .-.... 4-1 0 0 ° -u..ou (1) , 4.1 t) • n-n 1.) .--1 .c4,-.4 0 0 cl (I-i w ti-.1 i- eP eY ▪ • • 47 c) e o o C o o e e c) 0c) 0 e 0 6 6 6 6 6 6 6 6 6 6 cd 6 6 6 6 v-) te) te, Ln Ln Ln 4.) Ln Ln tr) tr) tr) V V V V V V V V V V V V V V V V te) te) 0 c) o . tr; tr) 0 W.) c) tr; tr; tr; C.) C> Ir; tr; tr; tri tr; tri tr; If NNNNNNNNNNNNNNNN ✓ V V V V V V V V V V V V V V V 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 tr; kr; tri tri tri tr; tr; tri tr; tr; kr; tri V V V V V V V V V V V V V V V V rn 0 0 0 tr) 0 0 0 0 0 0 0 cr) 6 0; 6 6 6 7 7 77i 0 tri ✓ 4-1 000 kr) 777 00 cc 6 6 c:; 6 c:; 6 6 t--- 6 6 C) CD CI n7777 C;) cc c tri tr; tri tri tri tri Ln tri tri W.; tr; tri tri tri V V V V V V V V V V V V V V V 0 0 0 cc t--• 0 0 0 on 0 CD 0 0 0 h 0 0 0 t:) ,-4 77777 7 LI-) cf-) V V cc NOC) 0 0 vo o V n7 V- V - 4 0 C)00 o c) 6 6 6 6 6 6 6 6 6 6 6 6 6c:; 6 6 000 tn 'ri 'ri Ln in kt) 'ri kr) V V V V V V V V V V V V V V V kt.) Ln Ln ✓ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 tri tri tri kr; tri tri tri tri tr; tr; tri tri tri tri tri tri V V V V V V V V V V V V V V V V ✓ 0 0 C> 0 0 0 0 C:? 0 0 0 0 O 0 0 tri Ir; CD tri CD C CD C) CD C). CD. (= CD. CD. c= C). 'ri 'ri tri tri tri tri tri kt-) Ln te-) tr) Ln triln V V V V V V V V V V V V V V V ✓ t-t:1 ✓ . kr; tri kr; tri kr; tri tntritr) Ln y') Ln ln V V V V V V V V V V V V V V V nC)N co d- 00 5 ,--ION cr)0(T s tel 0 N oc; ci) ai 00 C 1-4 00 1-4 te; eri n6 71- kt') (Ni N N 0000000C> 00 0 00 000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Ln tri tri 'ri kn tri tr) tr) tri tri tri kt) tn tn V V V V V V V V V V V V V V V ✓ --4N,--4N en,14 cd IDO cd cl tD0IDA (L) a.) cl cl b1) b.0 I. y-1 a.) a> ;•-n cl r:1-1 0 z 4 4 4 ti) a) 1.) a) 0 a) • v-4 • T-4 • v. • • g U U C.) C) C.) a) 7) 7:1 • 1-4 • ,•4 E E E .7d ".' Crt cl cd (...) d czt -g .4 .4 A A to td)t4) cd g CD g g g ta) ...;•-•+••-.•-n -4-y; V)V) C:C1 fil P:i ..t 48 Aluminum concentrations observed in soil samples ranged from 5,985-26,400 ug/g, with a mean concentration of 15,790 ug/g (Table 17). The highest aluminum soil concentrations were sampled from Cook's Lake, which can be correlated to significantly higher aluminum concentrations in the root and shoot tissues of Scirpus acutus and Scirpus americanus. Anemopsis californica, Lemna sp. and Scirpus americanus can be considered accumulators of aluminum according to Kabata-Pendias and Pendias (1992), who report accumulators as species containing more than 1,000 ug/g of aluminum in their tissues. All other species analyzed for aluminum in this study fall within normal ranges reported for terrestrial plants, 10-900 ug/g (Kabata-Pendias and Pendias, 1992; Markert, 1994). In all samples, except for one specimen of Anemopsis californica, aluminum was found at higher concentrations in the root tissues than in the shoots and leaves. Aluminum is reported to concentrate in the roots of many plant species, with translocation to plant shoots reflecting aluminum tolerance (Kabata-Pendias and Pendias, 1992). Arsenic The mean concentration of arsenic observed in naturally occurring wetland macrophytes in Arizona was 0.638 ug/g (Table 14). Lemna sp. was determined to have the highest arsenic concentration, with a range of 2.80-6.23 ug/g and a mean of 4.51 ug/g (Table 18). Anemopsis californica was found to have higher arsenic concentrations in leaf tissues than root tissues, with means of 1.00 ug/g and 0.721 ug/g respectively. Conversely, arsenic concentrations were greater in the roots than the shoots of all 49 Lr) oo 0 CA V) 0 Ln oo t--- oo cn n.e) od tr; ,t: N '—' n0 c Ln d•I• 00 V) VD CT en tr) tr) Le-) Ln Ln tr) • N N N N eNi (Ni (Ni N cNi V V V V V V (;'V V V V Lr) »..., (x Le) el V .71- (Ni V t--- cr) en 1-1 N VD "71- 1...1 Le-) en Ln oo CT CT d- N 0 0 c) 6 1 74/4 1--1 VD en r o c; (=, CNI .1-l0f) en ce) d• .q. 6 c) t--- -1' 1.-- I-- e--1 C:, 0, Lc) ,--, cc N ON N "71- ..1* Ô (Nr n-•4 V en N CA t--d- 0 71- N fl Oi en Lei Lri er, cr.) 11.) ,C) /-1 Lr) en 0 (7) N a., N 00 Lr) t--- V) •--1 •71- \O .-4 V 71- kr) WI 0 N N eNi 06 CY (Ni tr) tr) cc) N Ln (NI oo t---- kr) 0 CA .71- tr) 00 /1 1-4 en cr 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 en Ln in N N VD CA en ON Ln N 000 fl VD CA, —n •1C t-- "1O '.000 Le-) VD en oô oô en" •••••1 fl R en" en" .q." N o 00O Lr) Le--) (3' ON C; C1 cn 71- CA rf) v-4 Le-) rfl oo N NO N Cr) 6 4 ch. c4. tr.! e-4 kLC) In Le) oci ens VD Lr)" .7r" Lr)" Le-;' N N 000 oti C h (4. '-'. ir1 (-1 ci '.0 00 0 en 71- CA oo 0 .1- 0 re) re) (e) N •••4 tr) N oo N n-•4 Lc) of) N 71- kr) Le) If) Ln Ln (e-) Lr) kr) Le-) tr) in in Lr) Le-) eNi NNNNeNicNic-NieNiNN cNi cNi N N V V V V V V V V V V V V V V V V V 71" Cn. CO 0 0 VD 0 '.0 00 71- V:, tr) t:;) '.0 000000 rr! cr) Lc; 7t: `c). e‘i C7N. 9 tri Lo 0 0 0 If)00 0-n' If)i en Le-) N N 74' en en Le-) C 0 CA 00 0 CA 0 VD tr) Le-) rn en oo 0. Ô 06 Leis 1.-4 (I co) .--4 .--n • .. 0 75 C.) • v•-• 0 g 0 C/D N N c:3 • I. g g 0 0 tO bi) Cd al E1 P-4 ts1 ra-i 4 Ct3C3 b01:4 (,-St •1..4 eta • v-1 c). (1) ,._ cat "c) • . 5/) :W c:, 0 0 v..4 at 1.11) (1..) a) OZ 0 • • • (-.) L.) L.) Q ,..4 N 1-1 ... N N 0 g 0 C4 fr) 7r. r rA kr) 71- 0 0 0 0 0 0 0 0 Ln 6 '.0 Cfl kr) en c:) 06 v:) 060 0 01' 1-4 /-1 cn oo CI en 03 CI OA bl) a) • 0 .1::3 • .-4 ..W 0..1 oci) • "t a) C...) .. a) 7-.1 C.-.) cd g 0 0 0 bo . — .—, ..—; ...; • c4 cn PI MI 1:4 .'t › g g ad E 03 ct 4 - 0 4 A A to to to ▪ ▪ • o 50 0 0 *-0 0 rP., ..- rfl ce) 0 0 00 • 0 0 0 0 0 4.,1 -.-0.. . b.0 ..., C) (r) 0 00 NN ce) V;) C -c-d 0 E , 0 E . 7i a) 01) .1 —4 C5 0 1-• V;) 1-4 kr) t kr) 7t. 0 0 0 O• -•-+ O cd oo 00 N ce) •—• ce) cd ••- F•T-1 •g ;--• 0 0 ".0 C.) a) ,... ba Scl) '11 cd 0 › cd 0 1/4.0 C--- N kr) ce) ,—. ,-.4 Crn Crn N en 00 Crn 9,1: 0 C.-- 0 kr) ...1- N ‘.0 00 ce) 0 O 5 0 tO •0 0 = .0 0 a) a) 1.., -0 H a) a) 40 ›, 33 6 . o er; 6 6 6 6 o . 6 6 6 . n . . C.) r.""` Cr?. 1-4 c;\ c; kr) C)ce) (= 0 0 t— kr) N Cr) Cr) Cr/ Cr) Cs1 N 1-4 6 -Ikr)Q C2) N (xi C tri (2)ci) ce) ce.) op 0 cn ce) en en O 6 V V V V V n.c) 1-1 00 vnI 6 v 6 • • 6 6 '—' V '1" c' V v N. N N O kr) c.i... 0 cd 0 C .' 1-• a) 40 0N 0 a) .- a) v) ,---n. a) •01 ,--c.' Z (4-n 73 ..0 ;..• a) "E -0 -cr3 ..-• V —4 Ir) 1/4.0 k.0 0cd 6i 0 0 0 0 -0 0 0 c30 •,.. v) el.) ce) c) co a) ,...4 t cn a) 0 ,, ccl ...... H v) 44 44 44 44 4-1 44 E-4 a. 0 0 . an .4V) ...• 0 •••• .a Qtio •o' cu P1.4 ''s1 0 cf) cn 'Iii4t 1. Ln o 0 (2) bA • ,••4 o0 cd 0 6-, cn • •••4 En vp cn • ...1 cl) co r.' .w) 0 • ,.4 c.) U 0 0 cZt 0 0 0 "0 '0 ci k• n c‘,.kn e:3 Z14 " Z c-.. C:)..n ;Z4 4. • Z-1 ;,.. ... • 4.. ...4 • wa • v..4 nn•4 .zt"i5 Ç.)t.) r:1-4 Cn Ci] C") Co t..) Cn C.) Ci] tZ)4 ?% E•I (-) 0 ... 0 'A 0 g B . ,:la' . t M 0.) . t40 :74 ' I tn En C.) • c.) c43 •,.. c..)" 00 00 Z Z •"4: Z ZL4 -.. • Vn1 • IV kl.) e)Z kl.) '..5 cil cn O Z r., rZL, Ç»0 c•) an 47. - o 4 . V.1 o.) ci) 0 0 10 O O s-4 ci) O 0 Q-1 6-I 0 ›, as 0 i.n4 -t • › -_5, `-a. .)n----ao .. o 5 1-. C4 4-' 0 -2. o • 0 () '') t1-1 rj) L1":4 0 ..., 4-1 0 , 0 • .-1 (1) = z 0 cd a 0 > ... CI nt .4. 51 emergent species sampled, with mean concentrations of 1.08 ug/g and 0.200 ug/g respectively. Relatively high arsenic levels were observed in the root tissues of emergent species Scirpus americanus and Typha domingensis, with means of 1.72 ug/g and 1.17 ug/g each. The tree species Populus fremontii had a mean arsenic concentration of 0.216 ug/g, while no arsenic was detected in the tree species Fraxinus velutina, Salix gooddingii and the shrub Salix lasiolepis. Arsenic was detected in all of the water samples in this study, with a range of 7.4226.6 ug/L and a mean of 12.3 ug/L (Table 16). The highest arsenic concentrations in water samples were from St. David Cienega, with 25.8 ug/L determined at site 1 and 26.6 ug/L at site 2. Elevated arsenic levels in water samples from St. David Cienega correlated with the maximum arsenic concentration found in a single plant specimen, 8.25 ug/g, in the root tissue of Scirpus americanus at the same site. EPA (1998) has established the CMC for arsenic in surface waters to be 340 ug/L, arsenic concentrations determined in this study are well within permissible levels. In soil samples, arsenic concentrations were determined to range from 3.12-155 ug/g (Table 17). The highest soil concentration, 155 ug/g, was observed in a sample from Canelo Hills Cienega, while the next greatest soil arsenic concentration was only 34.6 ug/g. In this study, Anemopsis californica, Lemna sp., Scirpus americanus and Typha domingensis accumulated arsenic to a greater degree than the range Kabata-Pendias and Pendias (1992) report to be normal for terrestrial plants, 1-1.7 ug/g. Markert (1994) lists a much lower arsenic concentration for plants, 0.1 ug/g, similar to 63 percent of the 52 arsenic data in this study which was censored because values were below the minimum detection limit of 0.30 ug/g. Concentration means of all species analyzed fell within the reported 95% confidence limits for arsenic in freshwater vascular plants, 1.5-4.9 ug/g (Outridge and Noller, 1991). The mean concentration determined for arsenic in naturally occurring wetland macrophytes, 0.638 ug/g, was quite a bit lower than the mean concentration reported by Outridge and Noller for freshwater vascular plants, 3.2 ug/g (1991). Cadmium The mean concentration of cadmium observed in naturally occurring wetland macrophytes in Arizona was 0.195 ug/g (Table 14). Lemna sp. was determined to have the highest cadmium content, with a range of 0.971-1.55 ug/g and a mean of 1.26 ug/g (Table 19). Anemopsis californica and Scirpus americanus both had higher cadmium concentrations in root tissues than leaves and shoots, with means of 0.185 ug/g and 0.139 ug/g in roots and 0.100 ug/g and <0.16 ug/g in leaves and shoots respectively. In contrast, shoots of the emergent species Typha domingensis concentrated cadmium to a greater degree than the roots, with means of 0.159 ug/g and 0.111 ug/g respectively. Cadmium was not detected in the tissues of the emergent species Scirpus acutus. Tree and shrub species demonstrated an ability to acquire cadmium, a range of <0.16-0.989 ug/g was determined in leaves, although no cadmium was detected in samples of Fraxinus velutina. • t ▪ - • • o • - • ▪ 53 0 0 *-0 0 0 en '40 00 0 0 CD c) (7) 0 1-4 r.-4 kr) c:::, \ tr)V..D Ln 00 L4 r2 • 0 tù .4 "0 0 Ho E a) 0 tx0 .1 'rl cu ô0 ;••n 10 kr) cr) 000 N tri tri oci 0 0 en kn te) oo o co N en (---- ,--( C:n %.0 0•N tr) C)- 0 d- co en en ,--. 0 6 6 + 0 6 6 6 6 + 4 1- - -- F - -+" " - .- + N C) + il- - ci) tri en cd .... LLI •g oo in ,—. N 0 ,-+ en •:1- 0 0 0 v) O cd te-) 6 0 CC) + . - - +. -- r - --1 1.- 0 › CZ1 O 0 0 ..0 ti) 0 4... C..) O '-0 cl ml a) O E ba ..9 g .5 o a) = a) cu 4 ino 00 0 d" h nCD 4-4 VD te) 0 O 1-4 c c 6 6 6 6 V6 V d V 0 Ce kr) Ci; 0 c; c; .m N • •—• N 7:3 C4-4 4-1 a.) 0 a.) A a) cn ,.-•:,' 41.) H kr) in -0 >, a) a> ce '7 - VD VD nC;) .-i h 4-144 ca, 6 V 6 V 6 6 V V `,0 6 V V Td' .0 4. Z ..r) 4 cu .0 a.) ,00 5o Tri - kr) •—i ,—( rn cn W1 kr) 1/4.0 VD •--1 I::) N N 01 •—+ •••-i •—n •--1 0.) o a) .. ..-1) cn ZA co, ccs -a) 4 o a) a) 4 cct rc/i" : -5 E-(ra-(E-4E-4v)WWWWWW -..' .5 a. o0 cct En Z O ;•.1 1:3 C/) 0 › Cri 0 0 C.) C.) • n••1 Z 4.. 4... 0 t. 2 :;;:-.0-•••••••, (,) rn 0 0 . 1,1 0 s C".; cn Ln . IV C.) . 'V C.) ..., •,..., 0 ..4 : z,.,^a -i-E‘ 0 t.,sk4j '''S 0) ? ez ,1" zl, o •- • o o z., z a) cl) a) z ,4.. z '1 lzm 1.-.1 "'z 0) . 4.., cn •..., "'G 0) ''.0 .0 0 14 c.') •I ,.0 c.n cn Z o r.-± , o 0 ,.._ tzt tel c..) v4.) E, E-, . .t z., c) -.4 %I 'r, % ,--., tz., c.n ce) cn cn tn O c) U "C3 E a) e) ,.4a. .4.' g o 0.0 ••=: ' ••e., T) :El ' 0 +q 2 -,' c' j :1) ti-„, ao o -I..----- au E -.o - Ho --g .2. 2 -°) a) c4-( u, !.n-! cf) !=0ocd >- ,. ,$7 ? ) 54 Cadmium concentrations in water samples were all below the minimum detection limit, 5.0 ug/L (Table 16), which is also the EPA's established maximum contaminant level (MCL) for drinking water (EPA, 1998). The CMC suggested for cadmium is 4.3 ug/g, slightly lower than drinking water standards (EPA, 1998). Cadmium was also below the minimum detection limit for soil samples in this study, 2.5 ug/g (Table 17). Lemna sp., the only floating-leafed species sampled in this study, contained significantly higher cadmium concentrations than any other life form, which is contradictory to that reported by Outridge and Noller (1991). The mean concentration of cadmium determined in naturally occurring wetland macrophytes, 0.195 ug/g, is similar to that reported by Outridge and Noller (1991) for freshwater vascular plants, 1.9 ug/g, and Kabata-Pendias and Pendias (1992) for terrestrial plants, 0.05-0.2 ug/g. Chromium The mean concentration of chromium observed in naturally occurring wetland macrophytes in Arizona was 1.04 ug/g (Table 14). Lemna sp. was found to have the highest chromium concentration, with a range of 1.77-2.78 ug/g and a mean of 2.28 ug/g (Table 20). The terrestrial herb Anemopsis californica was determined to have a mean concentration of 1.85 ug/g chromium in its root tissues, and a mean concentration of 2.09 ug/g in its leaves. Emergent macrophytes, Scirpus acutus, Scirpus americanus and Typha domingensis, concentrated chromium to a greater degree in root than shoot tissues, with a mean root concentration of 1.13 ug/g and a mean shoot concentration of 0.721 ug/g for • • 55 0 0 '.0 0 0 0 0 0 0 0 0 0 0 0 0 0 c) 71: — ' - cf) N 4:*) n0 00 O r-- (0; N t-- O 0 r2 tifs i-i ici (1.) 0oE .. •0 F,. ,,, _.. :__. o0 ..o. _. -.0. Ec, -0. -80 " -0o ,c, r..7 -0. ..› c. 6 6 6 6 6 6 6 6 Cd 6 . 1 . . . . I . . , -' dl ± --4 + -4 -- F. - - 4 -- + + + + 2. 0 i .0 •-••4 e,i -4 - - ti.0 .2 0• •O a) "S a.) 00 0 en Ln en 00 (Ni oo C t .0 nr0 N 00 d" Ln e—I \ 6 (Ni 6 6 6 6 6 0 es co tr) VD. 00 00 6 ....., -2 1.a). . .. , N g1) t: CA ,--: E-0 -4.0 ,...x, ..., .4 s., , 00C, e•NI I . kr) • 00 Nen r•-•4 oo OOCr i•••-4 I 00 7/- N NC en N en N (1) 6 6 I. (cl cn N 6 6 6 6 nID N N ce) tr) V2/ VD en ..0 >, cs c.., <a .4 1. a) -0 0 0 0 is ..... 'V es a) a a) ..... . . z,3 . .... c.) a) ta. cn v) a) › cc: a) 0 ;-, CS C.) •.... CS C.) • v..., 4. 4. cn , cD ,4 c. • Z • :1 ;E 0) 0) . tn ..., $Z1.4 0) r' Cn tt Q.4 Zr 0 0 Z CS '')." ,Z3 'n1> ..` Et ô' ô o • ,.., :0 , 4. "'`1 4.1 t4) --a , . 0 0 'C3.)' r•I p cd fz, c. tn Z, c,) -4.., C.) Q CS z C.) C.) . Z..4 01) .4''-' 0) CS z ,.., • .4 • IV • 1, c>3 tn c ) cn c-D cn , ,, z..., zc,., 4 b0 • hi 0 C.), nt, 4.. Q., y) ô • ,..1 E CS -;:t C.) u) ô 0 ô 0 00 1...., En ri) ;..4 cn cn • cn ci • IV • P..1 +zt .?:s .--ti. 0 " ô' . 1 C.) , Z., 0 ;-n ss -. •. 0. cs w O ti) u) -`-' ziQ ''-' C) . 4.1 •,...i 4.1 En ô z W E-1 4-1 — 0 c 2 . 0 vl CD Cr\ en CO 0 d- N 00 1n N 00 00 en c:T t--- N cr) ,--1 tn t--- 0' \ en d". 0 0 CT .1- en 0 en 0 N en d- en c:T 4 o. C‘r; oc) en 00 00 C nC) 44 "7:1 tzt ,-•• SZ.1 E-4 0 ,0 .., 1.5 a) ..... a) -0 0 :g c.) 5 o a) t)i) ::÷.1 ' O *51 1..n .•,. to t 402, —. 0 0 'Izt ,-Z ZLi E.--, 0 •E - 0. ° ,t'.1P 0 ect 0 .0 s) 56 all three species. Tree and shrub species concentrated chromium to the lowest degree, with a range of 0.238-2.01 ug/g and mean of 0.632 ug/g. Chromium concentrations in water samples were all below the minimum detection limit, 5.0 ug/L (Table 16). EPA (1998) has established the surface water CMC for dissolved chromium species to be 570 ug/L for Cr III and 16 ug/L for the more toxic Cr VI. Chromium concentrations determined in natural wetlands for this study were within a permissible range. In soil samples, chromium concentrations ranged from 10.3-50.4 ug/g, with a mean of 23.5 ug/g (Table 17). The highest soil chromium concentration was sampled from St. David Cienega, where the maximum chromium concentration found in a single specimen, 7.14 ug/g, occurred in the leaves of Anemopsis californica. Chromium concentrations determined for wetland macrophytes in this study were higher than the range of 0.1-0.5 ug/g reported for terrestrial plants by Kabata-Pendias and Pendias (1992). The mean chromium concentration determined in naturally occurring wetland macrophytes was 1.04 ug/g, while that reported for freshwater vascular plants is 5.4 ug/g (Outridge and Noller, 1991). Markert (1994) lists a chromium concentration of 1.5 ug/g for all plants. Elevated chromium contents are reported in the literature for root tissues, which was observed only in emergent macrophyte species in this study (KabataPendias and Pendias, 1992). 57 Cobalt The mean concentration of cobalt observed in naturally occurring wetland macrophytes in Arizona was 0.317 ug/g (Table 14). Lemna sp. had the highest cobalt content, with a range of 1.11-2.69 ug/g and a mean of 1.90 ug/g (Table 21). Anemopsis californica was found to have a mean cobalt concentration of 0.683 ug/g in the leaf tissues and 0.586 ug/g in the roots. Emergent macrophytes analyzed in this study had cobalt concentrations up to six times higher in roots than in shoot tissues, with means of 0.316 ug/g and 0.093 ug/g respectively for all three species. Tree and shrub species were found to have a cobalt range of <0.135- 1.19 ug/g, and no cobalt was detected in the species Fraxinus velutina. Cobalt concentrations in water samples were all below the minimum detection limit, 5.0 ug/L (Table 16). There are no regulatory standards established by the EPA for cobalt. In soil samples, cobalt concentrations ranged from 3.86-20.5 ug/g, with a mean value of 11.4 ug/g (Table 17). The highest cobalt concentrations determined in soil samples were from Cook's Lake, which correlated with significantly higher cobalt concentrations in the tissues of Scirpus acutus and Scirpus americanus from the same site. The mean concentration of cobalt determined in naturally occurring wetland macrophytes was 0.317 ug/g, quite a bit lower than the mean reported by Outridge for freshwater vascular plants, 3.4 ug/g (1991). Cobalt concentrations reported as normal for terrestrial plants are 0.02-1 ug/g (Kabata-Pendias and Pendias, 1992) and 0.2 ug/g (Markert, 1994). In this study, Lemna sp. was the only species that accumulated cobalt to a greater degree than that which is reported for terrestrial plants. 58 L.T4 0 0 ".0 0 r2 a.) •,.. -0 bl) c) te-) enN vn4 1/4.0 N te-) oo N C ‹) N I. a) E 0.) "0 0 g bA .1 a) 8 0c. "0 -' N CnI C). C71 C c) OOtr) 0 •-n C 01 CN 00 0•N N C 0 d- 00 00 tel en n•0 N N te-) cn 00 00 N 4-1 00 v-) N CC cf) 4-4 N 6 6 6 6 0 6 6 6 6 11111 1111 4-. nC) en 00 00 tr) kr) k.0 4-- te) N k.a Nt N en .1- cr) VD 00 cn '.0n e en d- 0 en 0.n en N en 6 6 6 6 C; V 6 6 6 6 V cnC6 g MI 00 CO :1-n 44 a) › ca as 0.0 *0 as 0 0 0 *-0 ..a) 4.5 -0 g , 0 .... tzs) ".0 as O = 4.) a) ,.0 ,...-: Ln ,...-- .0 a) .. -0 g 0 ;.. a.) .4o N g ON kr) en 00 6 CNI 0.) F-: a) a) 0 a) -0 >, as a) 4. ....2.‘ Z en V ,.g V "Cil •4 $. 0.) ..0 ... ..g g g g ce a) 'rd C\ N Ln n E-1 4- V:. 1/4.0 V) 4-4 r•4 cn cn 0 -405 cd 0 a) 1-1 . C..) ..4 ri) cf) Q • IV " il C') '') $::=4, 0 Z.. 0 0) 0) .` c..) • tn .4 ''' .-r5a 0..) a> g 0 a) -,-, a) -10 E zsz .,... Ci) Vi vs a.) ca •,... C)a) au 4. as ., alii" ..... crl ta. = o ct 0 a) (i) .1.. 1 ....' 0 Oe - r• 1..' 0) ? Z ;il 0.) .. .,., 03 .0 p ).... %Ai '7) '' PL C. 0 rn tn Z ...., Lt.i C:t 0) 1-.4 0 0-4 Q.. -' O.) • 'ES". C,e Ci . 0 C' 4i5 0 4. o'') 48 • .4 ...4 4. ft. ÇP tg C:! •,-7.4 6• ,..., '..E3 0.) na • cn Ce) e-4 0 0 ;nI "Fn cn -n. tn -i ç.) 0 tn C.) 0 zi Z tl c..) .4." 0) 03 Ei., ZL-1 Q., 4. .i.; -..., •,... Ut..)C.) Cn Cn C'D .0 g .6-, ,..., p 0 . t).0 r-.. •F., 8 .'."8 .= 2 ›, ''' cd 1E.) re. › 0.) 4. n'-,, CO 0 0.) --I-. bA "E .26 • •-n ,.0 0 2 •P ri, 4-1 ti-i 4 t.i. a) a) ••••• a) --. .4,:-.1 O o cd •-•• el en et. 59 Copper The mean concentration of copper observed in naturally occurring wetland macrophytes in Arizona was 5.40 ug/g (Table 14). Lemna sp. concentrated copper to the highest degree, with a range of 23.3-41.7 ug/g and a mean of 32.5 ug/g (Table 22). Anemopsis californica had a mean copper concentration of 9.81 ug/g in its roots and 6.12 ug/g in shoot tissues. The emergent macrophyte species Scirpus americanus and Typha domingensis concentrated copper to a high degree in root tissues, with means of 9.40 ug/g and 9.50 ug/g respectively, while the shoot tissues had lower mean copper concentrations of 2.58 ug/g and 4.32 ug/g. Scirpus acutus had a mean copper concentration of 1.99 ug/g in its roots, while no copper was detected in its shoot tissues. Tree and shrub leaves were found to have copper concentrations ranging from <1.6-11.7 ug/g and a mean of 2.17 ug/g, with the highest concentrations determined in species of Populus fremontii and Salix gooddingii. Copper concentrations in water samples were all below the minimum detection limit, 50.0 ug/L (Table 16). EPA (1998) has suggested 1,300 ug/L as a drinking water MCL goal, while the surface water CMC is 13 ug/L. In soil samples, copper concentrations ranged from <25.0-101 ug/g, with a mean of 45.5 ug/g (Table 17). The highest soil copper concentrations were found at Bingham Cienega, a natural wetland located adjacent to a copper mine, and site 3 of Empire Cienega. The tree species Salix gooddingii and Populus fremontii, emergent macrophytes Typha domingensis and Scirpus americanus, and Anemopsis californica had significantly higher copper concentrations at the Bingham Cienega site. 60 0 0 '.0 0 rtz ,.., W o cr) kr) (6, .o ,f) c oe!, .;./2 151 c:2) z) 6 a) E a) tn E 0 0 cp•A .1 "ci cu o 0 4 00 N od,N v-1 00 CT VD kr) N N Coo d' 0, N C c;) izl 0 ort ..; tn cn cd .., :—. a) › ca a) ,--. bi) _ kr) oo 014, n •1 ce) aN V) S. 4. 0 1 I kr)c3) 0 Ir; 1 1 cc 1.1.) 1 1 ô '•0 c) a) -0. E0 I .2 0cd .) -2 0 a) a) a) 4. tr) N Ni Cl rn ce) cn 00 n.6 .0 <44 C). 0.n `,0 COO C N ,_:, v-) cf) Cr V Crn (Ni Ctn g cn-o 4 cu N ,g Z (1.) 0 .- cil .--e. Fq 71- N t-" h N VD t--- (Ni wi C.) 1-4 ,__, 6 oo N (N rn Cl N Cl , cNi c'N r-: k—, d' .--+ t \ i ,--( ,--; vi ,—, L.L. (-9) (T N ' 1' A . )0. v .; `r). N ` 0. c`i '—' \/ 77 N V 'V --i 7/ 4 77 V V 7 7 7 N tr) - N N 0, '11 kr) v:;) E-4 4.1 E-4 E-1 ci) n-•.1 te) cr) WWWWWW 6) ..0 ›sn 6) CU Cd -1 •••••n Ci, ,.= a) a) .o ... 0 0 7%4 0 .,., cd g a) 0 a) .4. IDA •4 cn iri cn a.) cc n ... c..) a) a) 4. re cep" -.4 .0 g c•c: tan . ;--. cd g .4 a) CU -.4 C4—. 0 cn C6 4.J 0 •n.4 . V.4 o ‘....., . FI; 4 ''.3 0,4 cn Ci '---4 Z •; Cn En %) Z "Zt C.) .,• .),s o 'Z'2 C 1 t.-14 cn lmEn .... 0 0 eq3 Q O) 1:2, V 0 Cn C.) En "Ci Z) cn cn "tt .,.., v 0 0 0 i-1 r,1 Ci) r,1 Z cs ts Ci C.) •,... .., 4.. S.. C1) 4) En cn te v v 0 0 i..I Cil tn • 1...1 , ..1 • rn En En z 4) tO tO CO ...a . IV 0 0 0 0 0 "0 "0 Ent1 En c..) Cn C.) Cn C.) C' 1-.5 a) 1 -à4 c.) &I ,4E _4' a) td) -,72, ' . ai -. rz • g o 11 0 .. '-,• : tot o : N z . 1 .5 ; m czt tt . . c„ ,e ki..., ---1 64 „Y a) I.,) !".t.1 0 0 0 1-1 rP 61 In this study, all species except for Lemna sp. fell below or within the reported normal copper range for terrestrial plants, 5-30 ug/g (Kabata-Pendias and Pendias, 1992; Markert, 1994), and the 95% confidence limits for freshwater vascular plants, 9.7-16 ug/g (Outridge and Noller, 1991). The mean concentration of copper determined in naturally occurring wetland macrophytes, 5.40 ug/g, was lower than the mean reported for freshwater vascular plants, 13 ug/g (Outridge and Noller, 1991). In all samples, copper was found at higher concentrations in root tissues than in shoots and leaves, which is consistent with that reported in the literature (Kabata-Pendias and Pendias, 1992). Lemna sp. was able to accumulate concentrations greater than 20 ug/g in its tissues, indicating excessive content (Kabata-Pendias and Pendias, 1992). Copper concentrations determined in naturally occurring wetland macrophytes were similar to those reported by Karpiscak et al. (1997, 1998) for Anemopsis californica leaves grown in a potable-fed constructed wetland system, and Populus frernontii and Typha domingensis shoots grown in an effluent-fed constructed wetland system (Figure 3). Fraxinus sp., Salix sp., Scirpus americanus roots and shoots and Typha domingensis roots sampled from naturally occurring wetlands were determined to have lower copper concentrations than those reported for constructed wetland systems fed effluent and potable waters (Karpiscak et al., 1997, 1998). As determined in the present study, Anemopsis californica, Scirpus americanus and Typha domingensis are reported by Karpiscak et al. (1997, 1998) to concentrate copper to a higher degree in root tissues than in shoots or leaves in constructed wetland systems. 62 ' el .4 bo a) .5 E -0 "01 o kr) Cn1 (2/2n) laddop -•-• 3 63 Iron The mean concentration of iron observed in naturally occurring wetland macrophytes in Arizona was 569 ug/g (Table 14). Roots of Scirpus americanus had the highest iron concentration, with a concentration range of 162-9,153 ug/g and a mean of 2,082 ug/g (Table 23). Anemopsis californica also concentrated high levels of iron, with a range of 123-4,938 ug/g and means of 1,257 ug/g in root tissues and 1,030 in leaves. The emergent species Scirpus acutus, Scirpus arnericanus and Typha domingensis concentrated iron up to eight times higher in root tissues than in shoots, with means of 1,185 ug/g and 169 ug/g for root and shoot tissues respectively. Lemna sp. was determined to have a mean iron concentration of 864 ug/g. Tree and shrub species Fraxinus velutina, Populus fremontii, Salix gooddingii and Salix lasiolepis concentrated the least amount of iron, with a range of 44.1-176 ug/g in leaf tissues and a mean concentration of 109 ug/g. Most water samples in this study were determined to have iron concentrations below the minimum detection limit, 100 ug/L (Table 16). EPA does not list drinking water MCL or surface water CMC values for iron, although a Criterion Continuos Concentration (CCC) for surface waters is suggested to be 1,000 ug/L to avoid deleterious effects to aquatic organisms (EPA, 1998). Sites that had detectable iron concentrations in water samples include Canelo Hills Cienega, Cook's Lake, St. David Cienega and Bingham Cienega. Site 3 of Cook's Lake had an iron concentration of 169 ug/L, which correlated with maximum iron concentrations in plant tissue of the species Typha domingensis and the roots of Anemopsis californica. 64 g [-T-1 '0' to a) 0 0 0 0 0 VD cr. ! cc 1/4°. Cr) c) cn 71- N cc cf.! 71. 0 0 0 0 0 0 0 kr) N ••71- C). •71- N Ln Le; s v--4 C71 6.0 t"--0 I.r) C11 .-.4 al if) le cr) N d' -. VI ,--i VI N 00 00 oo en 0e3 tel ,—, ,I Cr) 00 te) ,-.1 ,...., en n••c) 'Il gi. 1 i 1 1 ± Ir- -I- II: + ---1: ± -I- + + Ch = ,-," cr, to 1 1 ke-, . + ± -2-12 E 0 II 0 Or) .1 -0 0 ô 0 1... ^0 0 ccs c.) 0 cc: -,-. 4.1 ni 0 > ccs 0 .--. 0 0 '.0 C.) a)i) r cd "0 E g • A 0 . a> a> ;-n 0 kr) N 0C \ 00 "Zr en rn en c).n 4 en ,- t--c) n-o oc en 71" l0 4 0 (-Ni ON c) —I ,-, oc C\ ,--1 Ch 00 ,-1 N. ' N tr) ,--1 C' S .0 0a) -0 4.-n g 0 1... Ci; a) 0N 1=1 a) a) .. t a) ,.0 >-n ; a) Ln 00 lC) a> en vD 1/4c) Z c. "C l a) N 1 ce ) 00 00 k e-1 0 ' Cr CNi (--- 0 0 r2 t '.0 n.0 Crn Cn".71.' n4 cit) cf) v::) N .--+ 1/4.fD en n•c) Ln e--- n••° n.o te-) ,..I ON Il ,••4" il I ,••4 ,r1::) r-4 6 (.n4i 1.--1 N N N VD 4 0 Il 1-•-•4 un -1- C,1' (.1 1..1 6 en e-- n,-; ,--I.:1- n.c) v::, Jc) 1(1 N N ,•-.1 tf) erl te-) rn••••1 c,... . 00 mitr) 0, 0 il t2._ ci.‘ le) 0 4.) 01 n.c.) N CNi N kr, n—I 7-1 ,....1 tr) en en 11 cd Tu' .4 0 1... .4 '''.1 t ._ 0 0 0 eu -V) a) 0 ta) .,... 0 •n- Zoi a) c.) V4W t.11W 4[•1•4E-(E-1 c/)W cn (1) Ô › c d ,,... cl) 1-1 ,--. 0 0 C.) .... • C.) .... cn .z.-4, --, ci) cn 4., 0 • ,..., •n••.1 4.. •,..., ''''' ... 4 o ;••4 ct> v) Ô o :4, 0 ,... cn 0 ,4 cf) s,0 ..1 1-1 te. 4n ,..d tn 4.."' •l--. g 0 0 .,... .... c.) 0 44 o En t:3 z t:3 •,..., rn CZ. V • ''l VI • C.) *Z CI)" cd ri) 4-6 .'è4 c..) o e) r' ...... tn '1) %) C.) bi0 tO •,..., ''Z Z-1 Z •Z • ...., o...- C.) .,.. C.) 4) 4) 4) (1) '..0 0 C.) C.) ck '10 . 0 ...i • cn • tn • ...1 0 0 0 0 C r± CI s,a C1:44 En c2) "0 '0 cn IZZLI Ci-n c,1 c,) c,) 0 0 0 Z 0 NO 0 t3 ...., ,-.. Z-1 Z.n . .,.. F)" ,.... f.4.." n.-.Z 4... 4. .„ Cl) t)..) Z-1 .... ...., ..., Z.n $:=1.4 Z ,.?!..4)C.0'.18C.)C.)C.)C.) ,-6-4 Es4 C, Cn Cn Cn Co' 1•-4 0-4 "'' ..'q 64-4 ..3 ia' tan cl .1.-n 0 0 c Z cn cn cd 1-, a) cd .,... ce," ZZ .,.., Q 4.. tr) -8 'In -g w ,4 1 As I : 00 4, tu) 0 0 -..... _ 0 , 0 •,.. Là cn :el 44 '48 ,--, .1-.4 o o ce U › •-• t4 rn ..1. , ,I.1) --1 65 In soil samples, iron concentrations ranged from 7,753-63,393 ug/g, with a mean concentration of 20,682 ug/g (Table 17). Agua Caliente Park had the lowest soil iron concentration, 7,753 ug/g, the next highest was 13,586 ug/g. In this study, mean iron concentrations determined for Anemopsis californica and Scirpus americanus were higher than iron concentrations reported for crops and other terrestrial plants, 18-1,000 ug/g (Kabata-Pendias and Pendias, 1992; Markert, 1994). All other wetland macrophyte species analyzed in this study fell within the reported range for iron in terrestrial plants. Iron concentrations determined in naturally occurring samples of Populus fremontii were very similar to those reported by Karpiscak et al. (1997, 1998) for the species grown in effluent-fed and potable-fed constructed wetland systems (Figure 4). Anemopsis californica, Fraxinus sp. and the shoots of Typha domingensis were determined to have greater iron concentrations in naturally occurring samples than that which is reported for the same species grown in constructed wetlands (Karpiscak et al., 1997, 1998). Salix sp. and Typha domingensis roots were determined to have lower iron concentrations in naturally occurring plants than that which is reported for those grown in constructed wetland systems (Karpiscak et al., 1997, 1998). Naturally occurring root and shoot samples of Scirpus americanus were determined to have greater concentrations of iron than those sampled from potable-fed constructed wetland systems, and lower concentrations of iron than samples from effluent-fed constructed wetland systems (Karpiscak et al., 1997, 1998). 66 • +6 0 7s v") (2/2n) uo.q 67 Lead The mean concentration of lead observed in naturally occurring wetland macrophytes in Arizona was 2.57 ug/g (Table 14). Lemna sp. had the highest concentration of lead, with a range of 1.06-33.0 ug/g and a mean of 17.0 ug/g (Table 24). Anemopsis californica was determined to have a lead concentration range of <0.16-7.79 ug/g, and concentration mean of 3.36 ug/g in root tissues and 2.15 ug/g in leaves. The emergent species Scirpus americanus concentrated lead a factor of forty times higher in root tissues than in shoots, with mean concentrations of 10.1 ug/g and 0.249 ug/g respectively. Scirpus acutus was also found to have greater lead concentrations in root tissues than in shoots, with concentration means of 0.422 ug/g and 0.113 ug/g respectively. In contrast, Typha domingensis concentrated lead to a much higher degree in its shoots than root tissues, with means of 2.95 ug/g in the shoots and 0.811 ug/g in the roots. A concentration range of <0.16-18.8 was determined for the tree species. Populus fremontii and Salix gooddingii had the highest lead concentrations, while no lead was detected in leaves of the shrub Salix lasiolepis. Lead concentrations in water samples were all below the minimum detection limit, 5.0 ug/L (Table 16). EPA (1998) has suggested the CMC for lead in surface waters to be 65 ug/L. Lead concentrations determined in natural wetlands for this study were within a permissible range. In soil samples, lead values were determined to range from 6.31-65.9 ug/g, with a mean of 29.0 ug/g (Table 17). Patagonia-Sonoita Creek Preserve had the two highest 68 W -Ct ;El 79 ,... O N 0\ re) 0000 E 0 0 0 0 :12 . c) 0 en C71 V.D kr) 00 N do E 0 z to . •,::) co .6 o - 6. '10 C oo d' d- 0 7t:. oo. kn 0 0 - en oo 0 0 0,6 0 d r-I 1-4 N C N N 6-4 en cc) N › .0 63 CI) CG :4- r. r.z., -o C) g o o ..o0 a) ... 0,1 0 do I 1",:t 0 O NO en n.0 N1 d- ef-) eNi N NO td) oo -71- 1/40 n.0 en 0 -.6: CG kr) kr) 0 I 6 6 6 6 a) .1-.) Aco . •I 0 9 . Q., a) -c) 0 rt .'o 1... cu 0N 0 a) ,Z o €. k.0 N VD V') VD 0 C1 \ tn cr)oo ' N tr) -; ,0 Cr; N 6 Lc) 00 CT V 6 6 6 6 cNi ,. a) E-i kr6 C1n N oo o a) kr) a o .) ci 1nn1 (,11 N C7') ,•••1 Cr) 1 .6 c7, 4 1/4.0 >, cd Z cd 40 I. O.) 6 6 V V V V .0 I. en 1/4.0cn 1-1- 7-1 - .'cq a.) c:; 6 6 V V V V V C:; • .0 00 •-••n1 ,o 1-4 N a) V 1-1 1-1 Le-) I'd ,.9., 0 0 0 cd 7:1 4) 0 to •... vl cn cd .0 tr) n60 N N 1r) if) a.) •. Cl) cn 0 Ô ezt 0G) •.( a.) B0 C.) • wa Z 4. V) cn -i-J C.) • iv Z 4.. .1 C.) C.) cn .,, re) c• .„ ,n rn _,.., 0 e.; kit...... , Dr En Z.... 0 Q. 0 Z .,.., 0 o) Z 0) Z ..4.. 0) 'T--4 ''..-4 ''`I ".' +8 0 t'l ... .... 0 0 ,4 Z Z :,, ,-, tzt t21 6-, VI .1-E‘ .... re)En ) OM 0)C. ..., • ... ...,C.) Z 4. 4. Z.n ....4 0) ':6) CO "(''.34 el) ? rn Z Z4i 0 0-6 CI) .2) ...... vu ). -,.., "..E.:3 Cn Ci Cl) cn 48 0 0 % ..., 0 v) 0 ,Z 0 1.. Cn 4.4 En -5 Z') C.') ',-., ',-, Z 0) CO b.0 Z .,, CI) (10 • 1.4 Ci tn 0 0 0 0 0 0 N "0 "0 Cl)rn r• cn 0 izt z3 ,.... ,..z ;-t Q-1 Q-1 •,.., EL' • 4. Z1'' • .... • 4.. ...., • 4. IV ..., C:)., Z1, 'ZS CI Ce") c.) C'D Cn Ce/ E--d E--6 a) ... c...) a.) i.., a) cd 0L, v3 .-4-J -`a. g cd 0. 0 0 cd *-0 E•-n (..) 0 a) 4-, a.) -0 't c.) E 0 . -,a ....,‘ 0 0 to,- •, ,4 . 8 ..rD 44 , 2 , . >1 CI E Ca el) )› 4 -4 n 0.0 0 0 \ 0 II) e4' I-. 1:60 44 ... 4-6) 1) 0 •0 ,L) v) eL) :0 t = .E 0 "F4 10 › --. el rn .4. 69 soil-lead concentrations, 65.9 ug/g at site 1 and 59.7 ug/g at site 2, which did not correlate to unusually high lead concentrations in plant tissue samples from this site. The mean concentration of lead determined in this study for naturally occurring wetland macrophytes, 2.57 ug/g, was lower than that which is reported by Outridge and Noller (1991) for freshwater vascular plants, 8.1 ug/g. Markert (1994) reports a normal lead concentration of 1.0 ug/g for plants in general, while Kabata-Pendias and Pendias (1992) report a normal range of lead in terrestrial plants to be 5-10 ug/g. In this study, the concentration means of all species analyzed except for Lemna sp. and Scirpus americanus fell within the reported range for lead in terrestrial plants. High lead concentrations determined in the tissues of Lemna sp. and Scirpus americanus may indicate that they are lead accumulators. Lead concentrations determined in naturally occurring samples of Populus fremontii and Salix sp. were similar to those reported by Karpiscak et al. (1997, 1998) for the same species grown in effluent-fed and potable-fed constructed wetland systems (Figure 5). Anemopsis californica leaves and Typha domingensis shoots were determined to have greater lead concentrations in naturally occurring samples than that which is reported for the same species grown in constructed wetlands (Karpiscak et al., 1997, 1998). Anemopsis californica roots, Fraxinus sp., Scirpus americanus roots and shoots and Typha domingensis roots were determined to have lower lead concentrations in naturally occurring plants than is reported for those grown in constructed wetland systems (Karpiscak et al, 1997, 1998). 70 tn a60 , 0 .59 • (4 *(5 o 2 "'SSZ 'Tr (S/En) veal oE E 71, 71 Manganese The mean concentration of manganese observed in naturally occurring wetland macrophytes in Arizona was 747 ug/g (Table 14). Lemna sp. was determined to have the highest manganese content, with a range of 2,191-13,023 ug/g and a mean of 7,607 ug/g (Table 25). The tree species Salix gooddingii had unusually high concentrations of manganese in it's leaf tissues, with a range of 87.7-2,137 ug/g and a concentration mean of 1,091 ug/g. Scirpus acutus had an unusually high manganese content in its shoots, with a mean concentration of 1,052 ug/g. The emergent species Scirpus acutus, Scirpus arnericanus and Typha domingensis were found to have higher manganese concentrations in shoot tissues than in root tissues, with concentration means of 842 ug/g and 668 ug/g for roots and shoot tissues respectively. A mean concentration of 214 ug/g was determined for manganese in the root tissues of Anernopsis californica, with a mean of 108 ug/g for the leaves. The shrub species Salix lasiolepis was determined to have a mean manganese concentration of 166 ug/g, while the trees Fraxinus velutina and Populus fremontii had means of only 46.2 ug/g and 59.7 ug/g respectively. Most water samples in this study were determined to have manganese concentrations below the minimum detection limit, 10.0 ug/L (Table 16). There are currently no surface or drinking water standards established by the EPA for the regulation of manganese. Sites that had detectable manganese concentrations include Empire Cienega, Canelo Hills Cienega and Bingham Cienega. 72 ô 0 rE W t •-. "CI la'a) bb 0 0 0 0 0 0 0 0 0 0 0 0 0 N V') •--4 cri cri •;:r oo rei •—n N 00 Q 00 00 N •-4 IN- d-d- d' 00 tr) tra o0 N Crn (N: (Ni 4-4 kr) n•0 a>... E t> "0 Irs to •1 g o 4., •10 0 v3 ,n 0 •,.., cd Zi nO > 4) 34 c9 o 0 0 a) . %.0 w.1 ir) Ch ,-4 en d: CNi ô d nc) — C 00 Cr1 r*" . t--- 06 1....1 enN . kra CN v-) tr) 0 \ 0\ nONV0IraN —, N 4 4 I I 4 4 4 I 4 I I I 1 2. . -I- ± + + + ± +++++++ oc, N C tra co en N 0,, ,-4 N •-4 S S II O te-) CU ., bl) kr, 0 N CN ‘.0 t-- te) s 4 a) -0 E -2 cd o g = tu) '-g O mi • .0 a> = a> a) ,.0 ---:' c4 -0 o o 0 1-. a) N = a) .0 0 . .te) tr i t-- n0 ke-) 0 oo en I ( ) tr) ilo! ,C71- d-kr) r-,1 e-.1 N 0 —4 t-- 1...4 01 --, J 0 I-- en e.-1 (Nis ri r-.1 d' en cT Ch N te-) ,-1 V.;) .71- 0 Cf) "71- Cr) el 0 t---, , , .C;) —, d' N ,. r...1 fr) ,--i in1 N ..--n t41 I I i.il 71: 1 1 00 CI) CO \oc, on (- i o; ....4 1.1 N r"-: Cri C) , 't (Ni' N 00 CN en N en en en d- kr)O N N CN — 4 tr) ,-44 en ce) —44 tra 1/4C) n.0 En Cr) 0 ô › ct 0 c) En -,.., s-4 0 t3 C.) tn 0 i-i C.) • T..1 • IV Z a. so...:., c.) c,a •,.., cn • c4) - va — va Ln ô o .0 ...., , Z C:. ,..a .i.' 0) cl) ? v) .&t) Z "i.'3 ..1 Z•4 0.) 0 ...: ‘p L... • titi—.' 0 p va ZL4 0 0 0 Z 0 0 4 .--., •4.. k Zi k , -cl) 0) ,•.., Z Z ,4.. 0 0) CS ;a, CID , '' '' 6'1-1 '.-1 a> .0 ›, o 3 ,.... ce; .0 E-n ecis , a) ...-: 0 N 0 Z-44 tn tn 'n C/) 48 Cn - 0 ,4 $.4 C6 C'. z .t) ."1 z zCZt knZ o 1..1 (1) t,) te.> ,c.) c.) , 0 Ca ... (/) co 8 o += o o ()) b.0 4... , 0) Z Z c>) tu) Ca t..) 0 0 0 0 0 0 va c,i va va -0 -0 0 0 0 0 p p Z, Z., Z., Z•4 ... 4... 4... 4,.. •--0 ..-0 • • I...i • .4 • 1,1 CL.1 ZI C..) ç) c.) ça • IV cn ci' te) ce' E.4 E".4 o a) 0 ....-r, Z FI CL) i' .. CL) ..o ',Vs ... r0z 5 o et -0 a> a> o a) .5) o o o a) ctt .... (..) a> a) ,.... m o. o .... •= e-, .5. .0 czt o. 8 o o ,...., 0 o a> .... t> a> -0 !g gv) :a' ...." R 0 oti — •.-4, •4 . 4") ".5 0 -' 3•V. '..... , '17:t. VI 4. › 1-t ..0 .= •4-+ t ,..b..si) 0 E° u t) 0 • 2 0) 4.4 ,,, tee, 1) C.) 1:4 a) ,.. :7... o 0 cl i- •-. l'I 0 vl› VI 73 In soil samples, manganese values were determined to range from <20.0-30,936 ug/g, with a mean of 2,445 ug/g (Table 17). The highest soil manganese concentration, 30,936 ug/g, was sampled from Canelo Hills Cienega and correlates with high manganese concentrations in the tissues of Scirpus acutus at this site. Lemna sp., Salix gooddingii, Scirpus acutus, Scirpus americanus and Typha domingensis all had mean manganese concentrations greater than that which is reported for crops and terrestrial plants, 30-300 ug/g (Kabata-Pendias and Pendias, 1992; Markert, 1994). The mean concentration of manganese determined in naturally occurring wetland macrophytes was 747 ug/g, similar to that reported by Outridge and Noller (1991) for freshwater vascular plants, 730 ug/g. A broad range is reported for manganese in the tissues of freshwater vascular plants, 34-6,880 ug/g (Outridge and Noller, 1991), all species analyzed in this study had manganese concentrations within the reported range except for Lemna sp., with a concentration mean of 7,607 ug/g. Outridge and Noller (1991) report that floating-leaved species accumulate the lowest levels of manganese, which was not observed in the present study. Lemna sp. accumulated higher concentrations of manganese than any other life form. Concentrations of manganese reported by Karpiscak et al. (1997, 1998) for effluentfed constructed wetlands generally had the highest plant tissue concentrations of manganese (Figure 6). Manganese concentrations determined in naturally occurring samples of Anemopsis californica, Fraxinus sp., Salix sp., Scirpus americanus roots and shoots, and Typha domingensis shoots were greater than those reported for the same species in potable-fed constructed wetland systems (Karpiscak et al., 1997, 1998). 74 0 0 ( sn) osounsun w 00 •71- 75 Naturally occurring samples of Populus fremontii were determined to have lower manganese concentrations than those reported for potable-fed constructed wetland systems (Karpiscak et al., 1997, 1998). Nickel The mean concentration of nickel observed in naturally occurring wetland macrophytes in Arizona was 8.94 ug/g (Table 14). Lemna sp. was determined to have the highest nickel concentration, with a range of 12.6-205 ug/g and mean of 109 ug/g (Table 26). Anemopsis californica concentrated nickel to a greater degree in its leaf tissues than roots, with concentration means of 7.99 ug/g and 5.51 ug/g respectively. Emergent macrophyte species Scirpus acutus and Scirpus americanus had higher nickel concentrations in root tissues than in shoots, with means of 1.62 ug/g and 0.585 ug/g respectively in Scirpus acutus, and 21.0 ug/g and 1.73 ug/g in Scirpus americanus. Similar nickel concentrations were determined in the root and shoot tissues of Typha domingensis, with concentration means of 3.27 ug/g in the roots and 3.33 ug/g in the shoots. Tree species had a range of nickel from <0.54-143 ug/g, the species Populus fremontii and Salix gooddingii had the highest concentrations, 11.5 ug/g and 11.4 ug/g respectively. Nickel concentrations in water samples were all below the minimum detection limit, 5.0 ug/L (Table 16). The surface water CMC listed for nickel is 470 ug/L (EPA, 1998), nickel concentrations determined in natural wetlands for this study were well within a permissible range. • • ▪ ▪ • • 76 ro W 0 0 tin VI no 'go a) N C 0 0 N 00 N ,•••, N N N kr) lC) E a) -o cq Q)td) 0 1.. 0 "0 n•t) V:, Cl c N 'gr nCenNNNen0 00 0 N 00 N rr) r•-4 N Cr) r-1 00 1-4 vf In en N &•, :g .-. 0 0 .-0 0 0 1-> 0 0 › 0 ie 1 -- r -- P 4- + . 1 . 1 + + + 1- -- 01 0 C r) V) 01 01 tr; N 4- -- 1 1 4 -- 4 -- - - - .0 ‘ \ 0 if) 6 6 r-- N Cr) en en a) Aes 't) 0 = 00 '-g e O =' g .g .0 a) tu 7'43 ^0 &"'il'' ,g d) 0 1..n tu N 0 a.) cu a) a) -0 >-, c. Cf") V')•71:01N 000Cr) r"-r-4 - V) V) Ci -4. Cd 'Il 1 . O Cd .. •-•••1 en C:T N 00 N 00 Ln te) N 00 N (n .•-4 00 cr\ .--1 ...-: en 0 en Ln . -.• en 0) . ,..-.., C 00 6 oci _:). k r ) 01 1..1 N in-•4 6 ,—, 6 en d c,i cri me a) g .0 a) V.;) rsi 7r CA o ." .5 an ." ." 01 C; Cr) ,--i Cf) 00 '7I' °° 4 V') tr) 7r cl c) tri en ,—, inI ri-) ri-; N 1 4 4 ,41. (z:' ,r!, .1-4 kn Ln Ir) le) tr.) tr) c; c; cNi d 6 6 6 V .7r n..c) c; V V 1-1 V V V V cd 01 ,-n Z en t. Cid -0 I-. -0 "et ... O N N e--I rr) rel 1n1 0 cd V • a> a> = ttO ...n .I.i cn iti d) cd . a) -.. c.) tu cd g' .n-, :-... cn v) 0 ':5 , 0 $.-1 tr) cd •—n zt oEn Ç..) C.) Cl) ,,.., .'t.' 0 C..) .c0 • Z -i''' 4) ?. C.) . r.") ,_, „..: v oz 4) ..-.., 0) ti) ., R R 0 o z ...., 0 an 4) ''' Cl) 4) -.' 4.. 44 ci) te ..,, Ô t_.+ o 4,— --; 0 o o ,4. 7•-n tn ;-4 ci) ci) ti 0 O 0 ,4 ...., ;..• (zt ci) l'k' ci).) Cl) . 8-0 ..4 c c,1 0 ....., . 0 te t..) (I) '--.1 2=61 0 r:14 z_--? •U• ''C:3 o_ 0,,o Z•I 4) . C) Z Z C.) C) cl) 4) ri) Ln ....., Z tz; ci) C.) ..., 4) 0.1 t)-0 . ,.., • ;•t ... ..., ,--. "7-1 0 n -..Cn •,.. U Co, Z•4 )... C) to, • IV Q-1 4... • IV c.) Ce] Q 1 4 .;... Pc...1 Cn Z/.1 6-4 0 c.) a) ...a> -0 E g .,..,) Cl.) .te 7_1 • I (1) i • CJ tk0 .... 2 .g „ -) zi 0 0 0 0 0 0 " Cl) Cl) 0) 0• ] 0] 0'1 0 C:3 ,-- cd O a.) Ci .-t Z4 6-4 a) ' '' g, Ci, s 00 0 •ur ',.... '. 01) a l ' •. , ,.:4 . ,.n 0 • 0 0 cr, c+.1 ,,, t:-.1 a) a) .'-' 4a5 ° !t-. '2 o .1 , i4 P,,..)?. 77 In soil samples, nickel was determined in a concentration range from <10.0-38.7 ug/g, with a mean of 17.3 ug/g (Table 17). The highest soil nickel concentrations were sampled from Cook's Lake, which correlated with elevated nickel concentrations in the tissues of Scirpus acutus. Anemopsis californica, Lemna sp., Populus fremontii, Salix gooddingii and Scirpus americanus all had mean nickel concentrations greater than that which is reported for terrestrial plants by Kabata-Pendias and Pendias (1992), 0.1-5 ug/g, and Markert (1994) 1.5 ug/g. The mean concentration of nickel in naturally occurring wetland macrophytes was determined to be 8.94 ug/g, the mean concentration of nickel reported for freshwater vascular plants is 6.2 ug/g (Outridge and Noller, 1991). As the only free-floating, floating leaved life form included in this study, Lernna sp. accumulated higher concentrations of nickel than any other species, which is contradictory to that reported by Outridge and Noller (1991). Selenium The mean concentration of selenium observed in naturally occurring wetland macrophytes in Arizona was 0.607 ug/g (Table 14). Lemna sp. accumulated the highest concentrations of selenium, with a concentration range of 1.60-2.04 ug/g and a concentration mean of 1.82 ug/g (Table 27). Fraxinus velutina also accumulated selenium, a range of <0.8-2.60 ug/g was determined with a concentration mean of 1.50 ug/g. Selenium was detected in leaf tissues of the tree species Populus fremontii and Salix gooddingii, with mean concentrations of 0.914 ug/g and 0.681 ug/g respectively, 78 0 0 ..-, 5 r2 t-',, -0 1 44 0 CD 0 CD c) 00 I'S) N 00 0 0 0 0 +pl 0 on 0 0 1•••1 ri r,), .71 Cr CD V . 0 2a) 00 0 -0 0.0 0 .1 0 I. 1:3 cn 0 cn cd cd G) 71- 1/40 0 0 0 1...1 1-.1 0 0 C 00 N en oo tri 0 C; I'S) ..... 4-1 :g tu 0 cd 0 0 •,.., .-, a.) cn 00 0 N N oo In en c -- 0 ,--, O'N N ,—, "I' 1/40 •1 ,—, 0 0 (*Ni 6 6 6 o o o 6 6 o 6 N_ . - + ---4.-- CO 00 C) N 6 6 w? 'Zr 6 v..n1 N 00 00 00 00 00 Cr) \ 00 n0 6 6 6 0, .71- 6 CV V V 6 6 v i + tel C.) CU CCI a) •0 'S cd 0 2 g *-0 czt 0 =1 .0 0 a.) a) cq... .0 0 cd 0 4 a) V) N .0 A 0 a) (1.) cn 0C NCOOtn 0 Il cv V:, en ..71-. cNi cnicri ci en,-, . k 00 00 6 6 6 6 6 6 V y y y y y y y y y y y kr) 1/40 N N O '1")en 4-1 1...4 c.;) 00 00 0 Ô C) 0Ô OÔ. 00 00 00 NP 0 0 c— —; 6 6 ,—+ C=> , F-4cu ,.0 a) cd .0 en cl Z ,.0 ;.-. cl.) ..0 X) i—n ° ..0 g CA -0 u Z •4 cn cn a) a) ifi a.) ••-n c.) a> Ja. H 4. H H v) 4a 44 ;4 ci) .4v) ... GO CO 1`),.n 0 Z ..'1 t..) Z p e1/40 .. c» "I'.1 '---4 , 0 • T•a • C3 -..., .Z • I, -- 5.% . C.) .81) 0 t .i.' tt E C.) Z C.) 4) 4.) ;l'il . - vl ,.. 6.4 'k Cl p to') ci CO Z Z., 0 Cls ••] 0 40P = 0 CO cil a) +8 (1) -1V' 0 c.) o o • ..., Cn Z Z '' - = 0 C.) 0 t ti i —, 0 w 41 cn cll 4. Z4 a) 4. cd 154 Ct3 ôo ocl› • ,...1 cd =' GO tn 0 1.-n CO r•••) • IV ti • !..1 o i. t, "c3 .,?, Z, - u ... 4 - 4*4) 4) C.) .6it3 C.) 1:3 tl 0 Cl '-tt r = 4, 4) .--fc CI Co] t1 ts c..) 4.. •,.., • .4 z • ..1 ô tcl cc) Z 4) O.) 40 4 •...., Z•• ,..., 0 '1:3 t zt 'IV t..)C.)C.)C)N Co' Cn CI tn Esi E"-q .1.) .„, E 0 cd :a' Z.' g a) b.0 :7.1 • 0 -0 . tr) .0 • a `4 r...b e. C4-6)e ..--.. tu) o 3 0 - CO la. ,--. 1". E0 2 4-.) :2En • ,..), 4-1 4 4,4.-..1 2 V ,-, tu .=, 0 0 1— — ,-.1 r.,U › 79 while no selenium was detected in the tissues of the shrub Salix lasiolepis. The emergent species Scirpus americanus concentrated selenium to a greater degree in its root tissues than shoots, with concentration means of 0.937 ug/g and 0.498 ug/g respectively. Selenium was not detected in the emergent species Scirpus acutus or in the roots of Typha domingensis. Selenium was also not detected in samples of the terrestrial herb, Anemopsis californica. Selenium concentrations in water samples were all below the minimum detection limit, 25.0 ug/L (Table 16). EPA has established a drinking water MCL of 50.0 ug/L for selenium, although no surface water CMC is suggested (EPA, 1998). In soil samples, selenium was determined in a range from <2.5-10.3 ug/g, with most samples being below the minimum detection limit (Table 17). Sites that had detectable selenium concentrations include Patagonia-Sonoita Creek Preserve, St. David Cienega and Bingham Cienega. Elevated selenium levels in the water at Patagonia-Sonoita Creek Preserve correlated with maximum selenium concentrations in the tissues of Scirpus americanus from the same site. The mean concentration of selenium determined in naturally occurring wetland macrophytes was 0.607 ug/g, while Outridge and Noller report a concentration mean of 1.1 ug/g for selenium in freshwater vascular plants in uncontaminated areas. In this study, all of the species analyzed fell within the range reported by Kabata-Pendias and Pendias (1992) for selenium in terrestrial plants, 0.01-2 ug/g. Markert (1994) reports a selenium concentration of 0.02 ug/g for plants in general, which may represent the 89 80 percent of samples in this study that had selenium concentrations below the detection limit. Zinc The mean concentration of zinc observed in naturally occurring wetland macrophytes in Arizona was 26.1 ug/g (Table 14). Lemna sp. had the highest mean concentration of zinc, with a range of 68.4-212 ug/g and a mean of 140 ug/g (Table 28). Tree species Populus fremontii and Salix gooddingii were determined to have high levels of zinc in leaf tissues, with concentration means of 46.1 ug/g and 45.5 ug/g respectively, Fraxinus velutina accumulated the least of the tree species, with a mean of 8.18 ug/g. The shrub Salix lasiolepis had a mean zinc concentration of 28.3 ug/g. Emergent species, Scirpus acutus, Scirpus americanus and Typha domingensis, accumulated more zinc in roots than in shoots, with mean concentrations of 21.0 ug/g and 8.19 ug/g for root and shoot tissues respectively. Anemopsis californica was determined to have higher zinc concentrations in leaf tissues than in roots, with means of 15.8 ug/g and 14.4 ug/g respectively. Zinc concentrations in water samples were all below the minimum detection limit, 50.0 ug/L (Table 16). EPA has suggested a surface water CMC of 120 ug/L for the protection of aquatic organisms (EPA, 1998). Zinc levels determined in natural wetland samples for this study are with a permissible range. In soil samples, zinc was determined in a range of 16.9-268 ug/g, with a mean concentration of 97.2 ug/g (Table 17). The highest zinc concentrations in soil samples 81 o 4.1 o z o 1 o 0à!) . a) •fa -. -0 73 E o -0 I 0 - .E Q o o o o o Q o o Q o a) ô C CCI 00 •-•n oo 0 en 01 cri N 00 01 en 0 . •tr ;-74" N N. n.0 1/4.0 o o 00 g .0 a) 0 o '-0 c> a) .., a.) -0 E 0 • aa BO A d" h N .-1 6 •-.4 cri ce) _, ,--i ou 111111111 6.0 .2 0 a) o d- 00 00 h 00 d- - Lflfl '—'. 1/40 Ir) oo cn 00 N 00 •—n 14") h N Ln 06 Q N ,--1 ,—I 'd •—i t" N •—t N 71. il _ 00 0 4 4 N N 0 \ -..: vu •7t: cri rnC IIII 1/4.0 .46 6 N Nc •—n 00 .--4 ,.-4 1/40 Ln - (-fi o 06 •-...1 ce) d 1/40 en fd I , cl) I -0 Eif o ., Ln N N 00 ,. ....: ,1 N esi 00 00 eN1 4 t-- CTn ,-4 7-1 Cr; V C‘i V 4 vi \ W.) kr) C cr) \ c.) a) E-I 4-1 ' ci) r-14 ›, (1.) -1= cl Z "cil X) ;-f i•-n a) cn CL) › 0.) *(5) 0 0 En +c:5 45 0 0 1-4 Cr) à4 o Ci •E ,'.. z •,... '''' •...., •,... -.-- 0 1-. w -8 0 l_. :— '6.0 ' - • ,.`.1 ;:.n O.) ;il cv ,: (4.. 't:t C.) 0 cn 0cn cn 0 0 (Io Cl ... 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N 82 were from Patagonia-Sonoita Creek Preserve, although there was not a significant increases in plant tissue concentrations of zinc from this site. Zinc concentrations determined in the tissues of Anemopsis californica, Fraxinus velutina and Scirpus acutus were below the reported range for crops and terrestrial plants, 27-150 ug/g (Kabata-Pendias and Pendias, 1992; Markert, 1994). The mean concentration of zinc determined in naturally occurring wetland macrophytes was 26.1 ug/g, less than half that reported for freshwater vascular plants, 66 ug/g (Outridge and Noller, 1991). Lemna sp. accumulated concentrations of zinc that are considered to be excessive or toxic (Kabata-Pendias and Pendias, 1992). Zinc concentrations determined in naturally occurring samples of tree species Fraxinus sp., Populus fremontii and Salix sp. were less than those reported by Karpiscak et al. (1997, 1998) for the same species in potable-fed constructed wetland systems, and greater than those reported for effluent-fed constructed wetland systems (Figure 7). Anemopsis californica roots, Scirpus americanus roots and shoots, and Typha domingensis roots and shoots all had lower zinc concentrations than those reported in constructed wetland systems (Karpiscak et al., 1997, 1998). ▪ 83 ril=111M &),) r) ° E H s o +6.0 • .‘\ § i • •_., 0 1 -') . oliiiimin.u_ • E 0 •- ji)) CO 0 \ O EC) ci. `) 0 CO cn CO *É 4 -- q9., 8 E <1.) • •—n ts. oo r- ‘c) (2/2n) oui z g < j . 79;4 84 CHAPTER 5: CONCLUSIONS Lemna sp. was found to accumulate greater concentrations of the elements arsenic, cadmium, chromium, cobalt, copper, lead, manganese, nickel, selenium and zinc than any other naturally occurring wetland macrophyte in this study. Lemna sp. was especially efficient at concentrating manganese and nickel, having concentration means more than 10 times those of other species analyzed. In this study Lemna sp. was represented by only two samples, although separate studies have observed elevated concentrations of nutrients and heavy metals in species of Lemna (Sharma and Guar, 1995). Anemopsis californica accumulated the highest mean concentration of aluminum in this study, and was second to Lemna sp. in accumulating the elements chromium, cobalt and copper. Scirpus americanus accumulated the highest mean concentration of iron in its root tissues, and the second highest concentrations of aluminum, arsenic, lead and nickel. Leaves of the tree and shrub species Fraxinus velutina, Populus fremontii, Salix gooddingii and Salix lasiolepis generally had the lowest concentrations of nutrients and heavy metals, with a few unusual exceptions. Salix gooddingii accumulated high concentrations of manganese in its leaf tissues, second only to Lemna sp. Elevated concentrations of nickel and zinc were observed in the leaf tissues of Populus fremontii and Salix gooddingii, again only second to concentrations found in Lemna sp. Selenium was accumulated in the leaf tissues of Fraxinus velutina, almost three times higher than the concentration mean for all wetland macrophytes. 85 Root tissues of naturally occurring wetland macrophytes accumulated greater concentrations of aluminum, copper, iron and zinc than shoot and leave tissues in all species studied. Additionally, roots of the emergent species Scirpus americanus, Scirpus acutus and Typha domingensis accumulated greater concentrations of arsenic, chromium and cobalt than did the shoots of these emergent species. Typha domingensis was found to concentrate the elements cadmium, lead, nickel and selenium to a greater extent in its shoot tissues than roots, while Scirpus acutus and Scirpus americanus allocated these heavy metals to their root tissues. Anemopsis californica had higher concentrations of chromium, cobalt, manganese and nickel in its leaf tissues. Emergent species had greater manganese concentrations in shoots than in roots, with Scirpus acutus accumulating an unusually high manganese concentration in its shoot tissues. Macrophytic species that transfer metals into leaf and shoot tissues, such as Typha domingensis and Anemopsis californica, should be preferentially planted in constructed wetland systems that use harvesting practices for contaminant removal. Alternately, metal translocation is considered undesirable from an ecotoxicological standpoint, as accumulated metals could easily pass into the food chain through herbivorous and detritus feeders (Ye et al., 1997b). Macrophytic species which allocate metals in their root tissues, or those which do not concentrate metals at all, should be used in constructed wetlands that serve as a habitat for wildlife. Naturally occurring wetland macrophytes were determined to have mean concentrations of copper, lead and zinc within the same range as those reported by Karpiscak et al. (1997, 1998) for wetland macrophytes grown in potable and effluent-fed 86 constructed wetland systems, as summarized in Table 29. The mean concentration of manganese determined in naturally occurring wetland macrophytes was greater than the range of manganese reported for macrophytes grown in potable-fed constructed wetlands, although within that reported for effluent-fed constructed wetland macrophytes (Karpiscak et al., 1997, 1998). Mean iron concentrations determined in naturally occurring wetland macrophytes were greater than the ranges reported for iron in potable and effluent-fed constructed wetland plants (Karpiscak et al., 1997, 1998). Concentrations of nutrients and heavy metals reported by Outridge and Noller (1991) in freshwater vascular plants from uncontaminated environments were all greater than those determined for naturally occurring wetland macrophytes, with the exception of manganese and nickel (Table 29). Naturally occurring wetland macrophytes generally fell within the ranges reported as normal for nutrient and heavy metal concentrations in terrestrial plants, with the exception of manganese and nickel, which had higher concentrations than those reported for terrestrial plants, as summarized in Table 29 (Kabata-Pendias and Pendias, 1992; Markert, 1994). Maximum nutrient and heavy metal concentrations reported for wetland macrophytes from contaminated and uncontaminated environments (Vymazal, 1995) were two to five orders of magnitude higher than levels which were determined to be naturally occurring (Table 29). Mean concentrations of elements in the tissues of macrophytes from natural wetlands were similar to those reported for potable and effluent-fed constructed wetland systems, •0 ▪ 87 c+4 n-0 7:j 4 V) co" cr) ct cc s cz) 8 cr) (-.1 .4 (41 _ 4 'E00NO' as -.6 C-) o C> 00 cr) 6 6 6 6 V V o 0 N 0 tr) 0 t"-: 0 ,...a 0 7-.-1 S 0 CZ) kr) •—n ci; n-.4 '- I . 1n1 ON 0 en 4? C. 1 _ 6 . tr) t N00 CI,--1 1 tsl. ,--4 6 1 1 - I QQP I. _ (;) oo . 1 - I ,—, 6 6 6 on.; ,---, c-n 6 6 N co a) —, o c) en • v-4 a) .4 70 (l) NI. -4-, el t)Z•,- 4(1) E4 g bl) ••-• ----- 04 C74 la' u 4 5 .c) el cz) ,r. ,rnr. Ill 4-4 (n 1— 4 C, N,.., - 6,_2, 06 te..,. re) ,—, 'O 0 P., e) c) 4_, o 0 g c) --,-, i'd 0 a) c) 5 0 cr9 7:01 r i) rel . c9 N a s > I kt-) 71"" tri ) CT 7t -la' 7) 0 a) 0 a) ,.., .4 -1. _ I . (1.1 (-n cA v) — .6 4,... 01 (-NI e...1 C-js v., . 0 'e 4a .' 0 C ) C14 W rn 0 0 C.-) ,.. 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DAVID CIENEGA 96 97 APPENDIX E: AGUA CALIENTE PARK 98 99 APPENDIX F: COOK'S LAKE 100 1 01 APPENDIX G: BINGHAM CIENEGA 102 103 APPENDIX H: COMPLETE PLANT DATA BY STUDY SITE 104 t;1 00 r, VD N. vn VD vn CD r- N Nt CD vl N. N1 Cl 06 ,46 .4? r6 vi v6 • Vn CN r,cq cl Ch on on N. c0 00 00 oo oo oooo oo 00 00 op ce 00 c;,,; Ch Ch VD en 41 CN N. 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