Semipermeable Membrane DevicesBarber and others - Organic and Trace Element Contaminants in Water, Biota, Sediment, and USGS/WRIR 03-4129

 at the Tres Rios Treatment Wetlands, Phoenix, Arizona
 

ORGANIC AND TRACE ELEMENT CONTAMINANTS IN 

WATER, BIOTA, SEDIMENT, AND SEMIPERMEABLE 

MEMBRANE DEVICES AT THE TRES RIOS TREATMENT 

WETLANDS, PHOENIX, ARIZONA 

Larry B. Barber, Steffanie H. Keefe, Greg K. Brown, Howard E. Taylor, 

Ronald C. Antweiler, Dale B. Peart, Terry I. Plowman, David A. Roth, and Roland D. Wass 

______________________________________________________________________________ 

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 03-4129 

Denver, Colorado 

2003 
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

U.S. DEPARTMENT OF THE INTERIOR 

Gale A. Norton, Secretary 

U.S. GEOLOGICAL SURVEY 

Charles G. Groat, Director 

The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute 

endorsement by the U.S. Geological Survey. 

______________________________________________________________________________ 

For additional information write to: Copies of this report can be obtained from: 

Chief, Branch of Regional Research U.S. Geological Survey 

U.S. Geological Survey Information Services 

Box 25046, Mail Stop 418 Box 25286 

Federal Center Federal Center 

Denver, CO 80225 Denver CO 80225 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

CONTENTS 

CONTENTS.................................................................................................................................. III 

TABLES ........................................................................................................................................ V 

FIGURES.....................................................................................................................................VII 

CONVERSION FACTORS AND ABBREVIATIONS............................................................... IX 

ABBREVIATIONS ....................................................................................................................... X 

ABSTRACT.................................................................................................................................... 1 

CHAPTER 1 - INTRODUCTION.................................................................................................. 5 

Purpose And Scope...................................................................................................................... 5 

Acknowledgements ..................................................................................................................... 5 

Background.................................................................................................................................. 6 

Site Description ........................................................................................................................... 6 

Hayfield Site ............................................................................................................................. 6 

Cobble Site................................................................................................................................ 8 

Ecosystem.................................................................................................................................... 9 

CHAPTER 2 - SAMPLING APPROACH ................................................................................... 11 

Field Sampling Methods............................................................................................................ 11 

Water....................................................................................................................................... 11 

Fish.......................................................................................................................................... 13 

Semipermeable Membrane Devices ....................................................................................... 13 

Sediment ................................................................................................................................. 14 

Vegetation............................................................................................................................... 15 

Analytical Methods.................................................................................................................... 16 

Water....................................................................................................................................... 16 

Field Measurements............................................................................................................ 16 

Total and Dissolved Organic Carbon.................................................................................. 16 

Pesticides............................................................................................................................. 16 

Herbicides........................................................................................................................... 16 

Volatile Organic Compounds ............................................................................................. 17 

Wastewater-Derived Compounds ....................................................................................... 17 

Ethylenediaminetetraacetic, Nitrilotriacetic, and Nonylphenolethoxycarboxylic Acids.... 17 

Major Cations and Trace Elements..................................................................................... 19 

Anions................................................................................................................................. 25 

Nutrients.............................................................................................................................. 26 

Fish Tissue And Semipermeable Membrane Devices............................................................ 27 

Tissue Processing................................................................................................................ 27 

Organic Contaminants ........................................................................................................ 30 

Fish Tissue....................................................................................................................... 30 

Semipermeable Membrane Devices................................................................................ 31 

Trace Elements.................................................................................................................... 31 

Fish Tissue....................................................................................................................... 31 

Vegetation Tissue ............................................................................................................ 31 

Sediment ................................................................................................................................. 32 

Organic Contaminants ........................................................................................................ 32 

Trace Elements.................................................................................................................... 32 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

CHAPTER 3 - ORGANIC COMPOUNDS IN WATER, BIOTA, SEMIPERMEABLE 

MEMBRANE DEVICES, AND SEDIMENT.............................................................................. 35 

Water ......................................................................................................................................... 35 

Field Measurements................................................................................................................ 35 

Total And Dissolved Organic Carbon..................................................................................... 36 

Pesticides, Herbicides And Insecticides ................................................................................. 36 

Volatile Organic Compounds ................................................................................................. 38 

Wastewater-Derived Compounds ........................................................................................... 38 

Ethylenediaminetetraacetic, Nitrilotriacetic, And Nonylphenolethoxycarboxylic Acids....... 39 

Fish Tissue................................................................................................................................. 46 

Semipermeable Membrane Devices.......................................................................................... 50 

1998 Deployment.................................................................................................................... 50 

1999 Deployment.................................................................................................................... 52 

Sediment .................................................................................................................................... 52 

Bioaccumulation........................................................................................................................ 54 

CHAPTER 4 - INORGANIC CONSTITUENTS IN WATER, BIOTA, AND SEDIMENT ...... 59 

Quality Assurance...................................................................................................................... 59 

Accuracy ................................................................................................................................. 59 

Standard Reference Materials................................................................................................. 59 

Spike Recoveries..................................................................................................................... 59 

Blanks ..................................................................................................................................... 60 

Precision.................................................................................................................................. 61 

Water ......................................................................................................................................... 63 

Major Cations And Anions ..................................................................................................... 63 

Trace Elements........................................................................................................................ 64 

Nutrients.................................................................................................................................. 74 

Sediment .................................................................................................................................... 74 

Biota........................................................................................................................................... 74 

Vegetation............................................................................................................................... 74 

Fish Tissue .............................................................................................................................. 78 

CHAPTER 5 – REFERENCES CITED ....................................................................................... 85 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

TABLES 

2-1. Tres Rios Wetlands field sampling events, 1998................................................................... 12 

2-2. Tres Rios Wetlands field sampling events, 1999................................................................... 12 

2-3. Tres Rios Wetlands field sampling events, 2000................................................................... 13 

2-4. Forty-eight pesticide compounds determined by USGS NWQL Schedule 2001.................. 18 

2-5. Twenty-six herbicide compounds measured in water by the USGS Lawrence, Kansas 

laboratory ............................................................................................................................... 19 

2-6. Twenty-three insecticide compounds measured in water by the USGS Lawrence, Kansas 

laboratory ............................................................................................................................... 20 

2-7. Seven herbicide metabolites measured in water by the USGS Lawrence, Kansas 

laboratory ............................................................................................................................... 20 

2-8. Eighty-six volatile organic compounds measured in water by USGS NWQL Schedule 

2020 and 35 compounds measured by Schedule 2022 .......................................................... 21 

2-9. Forty wastewater-derived compounds measured in water by USGS Boulder, Colorado 

laboratory ............................................................................................................................... 23 

2-10. Ethylenediaminetetraacetic acid, nitrilotriacetic acid, and nonylphenol-ethoxycarboxylic 

acids measured in water by USGS Boulder, Colorado laboratory......................................... 24 

2-11. Major ions and trace elements measured in water, their atomic symbols, and method 

detection limits....................................................................................................................... 24 

2-12. Major ions and trace elements measured in fish tissue and method detection limits ............ 25 

2-13. Major ions and trace elements measured in vegetation tissue and method 

detection limits....................................................................................................................... 26 

2-14. Major ions and trace elements measured in sediment samples and method 

detection limits....................................................................................................................... 27 

2-15. Data on fish tissue samples collected in 1999 and 2000 and analyzed for organochlorine 

compounds and trace elements .............................................................................................. 29 

2-16. Twenty-eight organochlorine compounds measured in fish tissue, semi-permeable 

membrane devices, and sediment samples by USGS NWQL Schedule 2101....................... 33 

3-1. Summary of specific sampling information, field measurements, and organic carbon 

analysis for 1998 to 2000 water sampling events .................................................................. 36 

3-2. Concentrations of pesticides detected in water samples from the Hayfield 2 wetland, July 

28 to August 21, 1998............................................................................................................ 39 

3-3. Concentrations of 3,4-dichloroaniline and chlorpyriphos detected in water samples 

collected from the Hayfield 2 wetland and the Gila River at Bullard Avenue, 

August 1998........................................................................................................................... 39 

3-4. Volatile organic compounds detected in the 91st Avenue Wastewater Treatment Plant 

effluent at the Hayfield wetland inlet splitter box, February 16, 2000.................................. 40 

3-5. Volatile organic compound concentrations detected in the Hayfield 1 wetland 

February 16, 2000 .................................................................................................................. 41 

3-6. Concentrations of wastewater-derived compounds at the Tres Rios Wetlands and 

downstream Gila River sites, 1998 to 2000........................................................................... 42 

3-7. Concentrations of ethylenediaminetetraacetic acid, nitrilotriacetic acid, and nonylphenol 

monoethoxycarboxylate, nonylphenol diethoxycarboxylate, nonylphenol 

triethoxycarboxylate, and nonylphenol tetraethoxycarboxylate at the Tres Rios Wetlands 

and downstream Gila River sites, 1998 to 2000 .................................................................... 44 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

3-8. Concentrations of organochlorine pesticides in Tilapia whole-body and filet tissue, 

Gambusia whole-body tissue, and sediment samples from the Hayfield wetlands............... 48 

3-9. Concentrations of organochlorine pesticides in Tilapia whole-body, filet, liver, and other 

tissue and Gambusia whole-body tissue collected February 14, 2000 at the Hayfield and 

Cobble wetlands, and June 1996 at the 91st Avenue effluent channel................................... 49 

3-10. Concentrations of organochlorine pesticides and wastewater-derived compounds in 

semipermeable membrane devices deployed in the Hayfield 2 wetland inlet and outlet and 

the Gila River at Bullard Avenue, July 24 to August 21, 1998 ............................................. 51 

3-11. Concentrations of organochlorine pesticides in semipermeable membrane devices collected 

after 1, 2, 4, 6, and 8 week deployments at the Hayfield 1 wetland inlet and outlet, June 24 

to August 19, 1999................................................................................................................. 54 

4-1. Percentage of determinations for selected elements that fall within the specified range of 

recovery for the certified or most probable value of the spike addition in water samples .... 61 

4-2. Percentage of replicate samples whose relative standard deviations fall below the 

specified values...................................................................................................................... 62 

4-3. Summary of major cation results for water samples collected from the Hayfield wetlands 

inlet and Hayfield 2 wetland outlet, July to August 1998...................................................... 63 

4-4. Summary of duplicate major anion and cation results for water samples collected from the 

Cobble wetlands inlet, Cobble 2 wetland outlet, and the Gila River at Bullard Avenue 

during June 1999, and from the Cobble wetlands inlet, Cobble 1 and Cobble 2 wetlands 

outlets, Hayfield wetlands inlet, Hayfield 1 and Hayfield 2 wetlands outlets, the Gila River 

at 115th and Bullard Avenues, and the 91st Avenue dewatering well during 

February 2000 ........................................................................................................................ 65 

4-5. Concentrations of dissolved trace elements for water samples collected from the Hayfield 

wetlands inlet and Hayfield 2 wetland outlet during July to August 1998............................ 67 

4-6. Summary of duplicate trace element results for water samples collected from the Cobble 

wetlands inlet, Cobble 2 wetland outlet, and the Gila River at Bullard Avenue during June 

1999, and from the Cobble wetlands inlet, Cobble 1 and Cobble 2 wetlands outlets, 

Hayfield wetlands inlet, Hayfield 1 and Hayfield 2 wetlands outlets, the Gila River at 115th

and Bullard Avenues, and the 91st Avenue dewatering well during February 2000 ............. 69 

4-7. Nutrient data for water samples collected from the Hayfield wetlands inlet and the Hayfield 

2 wetland outlet during July to August 1998......................................................................... 74 

4-8. Trace-element composition data for duplicate sediment samples collected from the Cobble 

2 wetland inlet and outlet, June 23, 1998............................................................................... 75 

4-9. Trace-element composition data for softstem (Schoenoplectus tabernaemontani) and 

Olney’s (Schoenoplectus americanus) bulrush samples collected from the Cobble 2 

wetland inlet and outlet, June 23, 1998.................................................................................. 76 

4-10. Trace-element composition data for Gambusia whole-body and Tilapia whole-body, filet, 

liver, and other tissue samples collected from the Hayfield 2 wetland, July 23, 1998.......... 79 

4-11. Trace-element composition data for Gambusia whole-body tissue collected from the 

Cobble 2 wetland, and Tilapia filet and liver tissue collected from the Hayfield 1 wetland, 

February 14, 2000 .................................................................................................................. 81 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

FIGURES 

1-1. Site location and aerial photograph of the 91st Avenue Wastewater Treatment Plant and 

Tres Rios Treatment Wetlands............................................................................................... 7 

1-2. Hayfield wetlands site map.................................................................................................... 8 

1-3. Cobble wetlands site map ...................................................................................................... 9 

2-1. Semipermeable membrane device partitioning and containment structure ........................... 15 

2-2. Typical Tilapia specimen....................................................................................................... 28 

2-3. Tilapia dissected with a ceramic knife................................................................................... 28 

2-4. Numerous Gambusia specimens in holding jar ..................................................................... 30 

3-1. Hydrolab profiles of temperature, dissolved oxygen, pH, and specific conductance at the 

Hayfield 2 wetland inlet and outlet, July 24 to August 21, 1998........................................... 37 

3-2. Distribution of chloroform, bromodichloromethane, dibromochloromethane, 

1,4-dichlorobenzene, methylene chloride, tetrachloroethene, and toluene in the 

Hayfield 1 wetland, February 16, 2000 ................................................................................. 41 

3-3. Concentrations of select wastewater-derived compounds in the inlets and outlets of the 

Hayfield and Cobble wetlands and Gila River downstream sites, 1998 to 2000................... 43 

3-4. Concentrations of ethylenediaminetetraacetic acid and nitrilotriacetic acid in the 

Hayfield 2 wetland, July 24 to August 21, 1998.................................................................... 45 

3-5. Concentrations of ethylenediaminetetraacetic acid and nitrilotriacetic acid in the 

91st Avenue Wastewater Treatment Plant effluent and the Gila River at Bullard Avenue, 

1998 to 2000 .......................................................................................................................... 45 

3-6. Concentrations of nonylphenol monoethoxycarboxylate, nonylphenol diethoxycarboxylate, 

nonylphenol triethoxycarboxylate, and nonylphenol tetraethoxycarboxylate at the Hayfield 

2 wetland inlet and outlet, July 24 to August 21, 1998.......................................................... 46 

3-7. Concentrations of nonylphenol monoethoxycarboxylate and nonylphenol 

diethoxycarboxylate in the 91st Avenue Wastewater Treatment Plant effluent and the Gila 

River at Bullard Avenue, 1998 to 2000 ................................................................................. 47 

3-8. Concentrations of organochlorine pesticides in Tilapia and Gambusia whole-body tissue 

collected in the Hayfield 2 wetland, July 23, 1998................................................................ 48 

3-9. Concentrations of trans-nonachlor and p,p’-DDE in Tilapia whole-body, liver, and other 

tissue and Gambusia whole-body tissue collected in the Hayfield and Cobble wetlands, 

February 14, 2000 .................................................................................................................. 49 

3-10. Concentrations of organochlorine pesticides in Gambusia whole-body tissue collected in 

the Cobble wetlands, February 14, 2000 ............................................................................... 50 

3-11. Concentrations of endosulfan II, lindane, dieldrin, pentachloroanisole, trans-chlordane, cischlordane, endosulfan I, hexachlorobenzene, p,p’-DDE, heptachlor epoxide, transnonachlor, and cis-nonachlor in semipermeable membrane devices deployed at the 

Hayfield 2 wetland inlet and outlet and the Gila River at Bullard Avenue, July 24 to 

August 21, 1998..................................................................................................................... 53 

3-12. Concentrations of cis-chlordane, trans-chlordane, and trans-nonachlor in semipermeable 

membrane devices deployed in the Hayfield 1 wetland inlet and outlet, June 24 to 

August 19, 1999..................................................................................................................... 55 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

3-13. Concentrations of dieldrin, pentachloroanisole, lindane, and p,p’-DDE in semipermeable 

membrane devices deployed in the Hayfield 1 wetland inlet and outlet, June 24 to 

August 19, 1999..................................................................................................................... 56 

3-14. Concentrations of p,p’-DDE and trans-nonachlor in Tilapia whole-body, liver, and other 

tissue and Gambusia whole body-tissue, and inlet and outlet semipermeable membrane 

devices deployed in the Hayfield wetlands............................................................................ 57 

3-15. Concentrations of dieldrin, lindane, cis-chlordane, and trans-chlordane in Tilapia wholebody tissue and Gambusia whole-body tissue, and inlet and outlet semipermeable 

membrane devices deployed in the Hayfield wetlands.......................................................... 58 

4-1. Correlation plots of observed concentrations of antimony, arsenic, beryllium, chromium, 

vanadium, calcium, magnesium, sodium, silica, aluminum, boron, barium, iron, strontium, 

zinc, copper, lithium, manganese, molybdenum and nickel as a function of the Standard 

Reference Water Sample Program most probable value ....................................................... 60 

4-2. Plot of precision for the determination of cadmium as a function of concentration.............. 61 

4-3. Plots of dissolved calcium and sodium concentrations in water samples collected from the 

Hayfield 2 wetland inlet and outlet on various days from July 24 to August 18, 1998......... 64 

4-4. Plots of dissolved arsenic, copper, lead, and zinc concentrations in water samples 

collected from the Hayfield 2 wetland inlet and outlet on various days from July 24 to 

August 18, 1998..................................................................................................................... 66 

4-5. Plots of dissolved aluminum, arsenic, cadmium, copper, lead, and zinc concentrations in 

water samples collected from the Gila River at 115th and Bullard Avenues, the Cobble 

and Hayfield wetlands inlets and outlets, and the 91st Avenue dewatering well, 

February 2000 ........................................................................................................................ 73 

4-6. Plots of aluminum, arsenic, cadmium, copper, lead, and zinc concentrations for softstem 

(Schoenoplectus tabernaemontani) and Olney’s (Schoenoplectus americanus) bulrush 

samples collected at the inlet and outlet of the Cobble 2 wetland, June 23, 1998................. 77 

4-7. Plot of 27 selected trace-element concentrations for Gambusia and Tilapia whole-body 

tissue collected at the Hayfield 2 wetland, July 23, 1998...................................................... 78 

4-8. Plots of arsenic, copper, mercury, and lead concentrations in whole-body Gambusia and 

selected body parts of Tilapia specimens collected from the Cobble and Hayfield wetlands, 

February 14, 2000 .................................................................................................................. 84 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

CONVERSION FACTORS AND ABBREVIATIONS 

Multiply By To obtain 

Length 

centimeter (cm) 0.3937 inch (in) 

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi) 

micrometer (μm) 10-6 meter (m) 

nanometer (nm) 10-9 meter (m) 

Area 

square meter (m2) 10.76 square feet (ft2) 

square meter (m2) 0.00247 acre (ac) 

square meter (m2

) 10000 hectares (ha) 

square kilometer (km2

) 0.3861 square mile (mi2) 

Volume 

liter (L) 0.2642 gallon (gal) 

cubic meter (m3) 1.308 cubic yard (yd3) 

milliliter (mL) 1000 liter (L) 

Mass

gram (g) 0.03527 ounce avoirdupois (oz) 

kilogram (kg) 2.205 pounds (lb) 

milligram (mg) 1000 gram (g) 

Flow

meter per second (m/s) 3.281 foot per second (ft/s) 

cubic meter per second (m3/s) 35.31 cubic feet per second (ft3/s) 

cubic meter per second (m3/s) 22.82 million gallons per day (mgd) 

cubic meter per second (m3/s) 86400 cubic meter per day (m3/d) 

Concentration

milligrams per liter (mg/L) parts per million 

nanogram per liter (ng/L) parts per trillion 

microgram per gram (μg/g) parts per million 

microgram per kilogram (μg/kg) parts per billion 

micrograms per liter (μg/L) parts per billion 

Miscellaneous

cm

2

/mL – square centimeter per milliliter 

mS/cm – millisiemens per centimeter 

Temperature in degrees Celsius (°C) can be converted to degrees Fahrenheit (°F) as follows: 

 °F = 1.8 (°C) + 32 

______________________________________________________________________________

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

ABBREVIATIONS 

BHT - butylatedhydroxytoluene 

BPA - bisphenol A 

BOR - Bureau of Reclamation 

C1 - Cobble 1 wetland 

C2 - Cobble 2 wetland 

C18 - octadecyl-bonded porous silica 

CAFF - caffeine 

CAS - Chemical Abstract Services 

CHO - cholesterol 

CLLE - continuous liquid-liquid extraction 

CO2 - carbon dioxide 

COP - coprostanol 

o,p'-DDD - 1,1-Dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane 

p,p'-DDD - 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethane 

o,p'-DDE - 1,1-Dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethylene 

p,p'-DDE - 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene 

o,p'-DDT - 1,1,1-Trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane 

p,p'-DDT - 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane 

DOC - dissolved organic carbon 

DO - dissolved oxygen 

DUP - duplicate 

E - estimated 

EDTA - ethylenediaminetetraacetic acid 

d12-EDTA - ethylenediaminetetraacetic acid with 12 deuterium atoms replacing hydrogen 

DOLT-1 - National Research Council of Canada Dogfish muscle standard reference material 

DORM-1 - National Research Council of Canada Dogfish liver standard reference material 

ESA - ethane sulfonic acid 

EST - Environmental Sampling Technologies 

GC - gas chromatography 

GC/MS - gas chromatography/mass spectrometry 

GPC - gel permeation chromatography 

H1 - Hayfield 1 wetland 

H2 - Hayfield 2 wetland 

HOC - hydrophobic organic compounds 

ICP/AES - inductively coupled plasma/atomic emission spectrometry 

ICP/MS - inductively coupled plasma/mass spectrometry 

LRL - laboratory reporting level 

MDL - method detection limit 

ND - not determined 

NA - not available 

NAWQA - National Water Quality Assessment 

NCI - negative chemical ionization 

NIST - National Institute of Standards 

NP - nonylphenol 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

NPEC - nonylphenolethoxycarboxylate 

NP1EC - nonylphenolmonoethoxycarboxylate 

NP1EO – nonylphenolmonoethoxylate 

NP2EC - nonylphenoldiethoxycarboxylate 

NP3EC - nonylphenoltriethoxycarboxylate 

NP4EC - nonylphenoltetraethoxycarboxylate 

NTA - nitrilotriacetic acid 

NWQL - National Water Quality Laboratory 

OP1EO - octylphenolmonoethoxylate 

PCB - polychlorinatedbiphenyl 

% REC - percent recovery 

PTFE - polytetrafluoroethylene 

QA - quality assurance 

QA/QC - quality assurance/quality control 

RSD - relative standard deviation 

SIM - selected ion monitoring 

SPE - solid phase extraction 

SPMD - semipermeable membrane devices 

SRM - standard reference material 

SRWS - standard reference water sample 

TC - total carbon 

TIC - total inorganic carbon 

TOC - total organic carbon 

TOP - tert-octylphenol 

TRI - triclosan 

USEPA - U.S. Environmental Protection Agency 

USGS - U.S. Geological Survey 

UV - ultraviolet 

UV254 - ultraviolet light adsorption at 254 nm 

v/v - volume/volume 

VOC - volatile organic compounds 

WWTP - wastewater treatment plant 

w/w - weight/weight 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

ORGANIC AND TRACE ELEMENT CONTAMINANTS IN WATER, 

BIOTA, SEDIMENT, AND SEMIPERMEABLE MEMBRANE DEVICES 

AT THE TRES RIOS TREATMENT WETLANDS, PHOENIX, ARIZONA 

Larry B. Barber, Steffanie H. Keefe, Greg K. Brown, Howard E. Taylor, 

Ronald C. Antweiler, Dale B. Peart, Terry I. Plowman, David A. Roth, and Roland D. Wass* 

ABSTRACT 

The Tres Rios Demonstration Treatment Wetlands located near Phoenix, Arizona are 

sustained by effluent from the 91st Avenue Wastewater Treatment Plant (WWTP). A series of 

sampling events were conducted between 1998 and 2000, and the results of organic and 

inorganic analysis of water, sediment, biota, and semipermeable membrane devices (SPMD) are 

presented here. The free-water surface wetlands consist of shallow (0.3 meter) zones containing 

emergent vegetation (softstem bulrush, Schoenoplectus tabernaemontai, and Olney’s bulrush, 

Schoenoplectus americanus), and deep zones (1.5 m) without vegetation. Conditions ranged 

from aerobic to anaerobic between the wetland inlet and outlet locations and temperatures were 

relatively constant, and there was little removal of specific conductance, total and dissolved 

organic carbon, and major anions and cations. Several pesticides and herbicides were detected in 

water samples including carbaryl, diazinon, 3,4-dichloroaniline (degradate of linuron and 

diuron), prometon, and simazine. Volatile organic compounds detected include 

bromodichloromethane, chloroform, dibromochloromethane, 1,4-dichlorobenzene, methylene 

chloride, tetrachloroethene, and toluene. 

 Concentrations of ethylenediaminetetraacetic acid (EDTA), a metal complexing agent 

and indicator compound of wastewater-impact, were greater than 100 micrograms per liter 

(μg/L) in the effluent and were reduced 75% between the wetland inlet and outlet. In contrast, 

concentrations of nitrilotriacetic acid (NTA), a more biodegradable metal complexing agent, 

were lower (less than 10 μg/L) and remained relatively stable in the wetlands. Downstream of 

the 91st Avenue WWTP effluent discharge location, the levels of EDTA in the Gila River 

decreased by 77% after 12 kilometers (km) of transport. 

 Alkylphenolethoxylate (APE) compounds are potential endocrine disrupting chemicals 

derived from nonionic surfactant degradation and are commonly detected in wastewater 

effluents. The most abundant APE-derived compounds were nonylphenolethoxycarboxylic acids 

(NPEC) which are hydrophilic (water soluble) degradates that occur as ionic species. The 

combined nonylphenolmonoethoxycarboxylate and nonylphenoldiethoxycarboxylate (NP1EC 

and NP2EC) levels in the effluent were greater than 100 μg/L and decreased 47% and 36%, 

respectively, in the treatment wetlands. Concentrations of nonylphenoltriethoxycarboxylate and 

nonylphenoltetraethoxycarboxylate (NP3EC and NP4EC) were lower and relatively stable at the 

wetland inlet and outlet locations. Combined NP1EC and NP2EC concentrations greater than 50 

μg/L were detected in the Gila River 12 km downstream from the 91st Avenue WWTP discharge. 

Other NPE-derived compounds that were detected include nonylphenol, octyphenol, 

nonylphenolmonoethoxylate, nonylphenoldiethoxylate, octylphenolmonoethoxylate, and 

octylphenoldiethoxylate. A variety of other organic wastewater contaminants also were detected, 

including caffeine, triclosan, and coprostanol. 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

In 1998, tilapia (Tilapia mossambica) and mosquito fish (Gambusia affinis) collected 

from the wetlands showed accumulation of p,p’-DDD, p,p’-DDE, and dieldrin. In 2000, Tilapia

showed accumulation of p,p’-DDE and trans-nonachlor. Gambusia collected in 2000 had 

elevated concentrations of cis- and trans-chlordane, p,p’-DDE, dieldrin, lindane, transnonachlor, and polychlorinatedbiphenyls. Tilapia appeared to be less susceptible than Gambusia

to accumulation of hydrophobic organic compounds (HOC) on a mass basis. Although the lipid 

content of the Tilapia liver tissue was equivalent to the whole-body Gambusia, concentrations of 

p,p’-DDE and trans-nonachlor and were 3 to 5 times higher in the whole-body Gambusia than in 

the Tilapia liver. The absence of contaminants in the Tilapia filet tissue indicates low risk to 

human populations that eat the fish. In the 2000 sampling, all of the compounds detected in 

Tilapia were detected in the Gambusia, but the Gambusia also contained additional compounds. 

 The SPMD showed elevated concentrations of HOC that potentially can bioconcentrate 

in the lipid of aquatic organisms. SPMD deployed for 28 days in 1998 accumulated cis- and 

trans-chlordane, p,p’-DDE, dieldrin, endosulfan I, endosulfan II, heptachlor epoxide, 

hexachlorobenzene, lindane, cis- and trans-nonachlor, oxychlordane, and pentachloroanisole. 

The SPMD outlet concentrations showed a 70% to >99% reduction relative to inlet 

concentrations. During 1999, a time-series experiment (SPMD were collected 1, 2, 4, 6, and 8 

weeks after deployment) was conducted to determine SPMD uptake rate characteristics in the 

treatment wetlands. The results indicate that cis- and trans-chlordane, and trans-nonachlor 

achieved steady state within 28 days, and that consistent with the 1998 results, there was >70% 

removal across the wetland. Dieldrin, lindane, and pentachloroanisole showed linear uptake 

during the initial part of the exposure (first 4 weeks) followed by clearance in the later part of the 

study. Dieldrin concentrations decreased 64% between the inlet and outlet, lindane decreased 

37%, and pentachloroanisole decreased >90%. Concentrations of p,p’-DDE in the SPMD 

increased over time and demonstrated that both internal loading and removal mechanisms were 

occurring within the wetland. 

Both the Gambusia and Tilapia, and the SPMD data indicate accumulation of p,p’-DDE, 

dieldrin, and trans-nonachlor, whereas the Gambusia and SPMD also accumulated cis- and 

trans-chlordane, and lindane. The inlet SPMD contained elevated concentrations for each of 

these compounds relative to the outlet and values measured in the fish tissue. The Gambusia

concentrations were generally equivalent to those measured in the outlet SPMD. 

 Although there was a slight increase in the wetland outlet concentrations relative to the 

inlets, the major-ion chemistry indicated little change during wetland treatment. This is 

consistent with specific conductance results, which are an indirect measure of total dissolved 

ions. A large suite of dissolved trace elements were detected, and as would be expected, varied 

significantly in their behavior in the wetlands. For example, dissolved arsenic concentrations in 

the wetland outlets were similar to (averaged 9% higher) the inlet concentrations, indicating no 

removal and the slight concentrating effects of evapotranspiration. In contrast, copper underwent 

significant removal (>90%) during wetland treatment and lead and zinc were removed to a lesser 

extent (>50%). Some elements such as cadmium and the rare earth elements, had higher 

concentrations in the outlets than the inlets indicating internal loading. 

 The sediment and bulrush vegetation had trace element distributions in general agreement 

with the water composition, although for many elements, concentrations in the sediment and 

vegetation were much higher. For example, concentrations of lead, zinc, arsenic, copper, and 

cadmium were 20, 25, 50, 1000, and 10,000 times higher in the vegetation respectively than in 

the water. 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

 Trace element distributions in the fish tissue were similar between the Tilapia and 

Gambusia whole-body analyses, and were in general agreement with the water composition. The 

concentrations of most trace elements in the Tilapia filet tissue were very low, whereas 

concentrations in the liver tissue were an order of magnitude higher. 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

CHAPTER 1 - INTRODUCTION 

Water remains a scarce resource in the Southwestern United States, prompting many 

cities to reclaim treated wastewater effluent to satisfy growing municipal water demands. 

Constructed wetlands are increasingly being implemented to provide supplemental treatment to 

wastewater treatment plant (WWTP) effluents while achieving wildlife habitat goals. Wetlands 

can maximize biological and vegetative diversity while sequestering, assimilating, and 

transforming a wide variety of organic compounds and trace elements. 

Residual wastewater contaminants can have a profound effect in arid regions due to high 

evaporation and evapotranspiration rates, which can reduce dilution and assimilation capacity by 

native stream water. Human, wildlife, and environmental health concerns may exist due to 

prolonged exposure to trace levels of chemicals in wastewater-dominated systems. Aquatic 

organisms living in treatment wetlands potentially can accumulate anthropogenic compounds 

through successive food pathways resulting in acute toxic effects and long-term ecosystem 

disruption. The potential for hydrophobic organic compounds (HOC) and trace elements to 

bioaccumulate is an important consideration in design and policy decisions related to constructed 

wetlands supplied by wastewater effluents. 

PURPOSE AND SCOPE 

This research originated from an interagency agreement between the Bureau of 

Reclamation (BOR), Technical Service Center, Water Resource Services of Denver, Colorado, 

and the U.S. Geological Survey (USGS) in Boulder, Colorado. The agreement emphasized 

studies to assess the potential for bioaccumulation and biotoxicity of HOC and trace elements in 

aquatic organisms inhabiting effluent-dependent wetlands and stream systems. The objective of 

this report is to present analytical results for water, biota, and sediments for the Tres Rios 

Demonstration Treatment Wetlands (Tres Rios Wetlands) located near Phoenix, Arizona. 

Additional goals were: 

• Determine HOC and trace elemental contaminant attenuation within the wetland basins. 

• Assess mechanisms of bioaccumulation for chemicals present in biota. 

• Evaluate analytical methods for determining bioaccumulation. 

• Assess wastewater impacts at downstream locations 

This report summarizes research on HOC and trace elements conducted from 1998 to 

2000. Water, sediment, fish, and semipermeable membrane device (SPMD) samples were 

collected concurrently to provide an overview of wetland biota and site conditions. The samples 

were characterized by a variety of analytical methods. 

ACKNOWLEDGEMENTS 

This work could not have been completed without the assistance of Eric Stiles, Marvin 

Murry, and Will Doyle (BOR) and Paul Kinshilla, Ronald Elkins, and Wes Camfield (City of 

Phoenix). Mike Thurman generously provided the pesticide, herbicide, and herbicide metabolite 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

analysis. Thanks to Kate Campbell, Tom Leiker, Steve Zaugg, Donna Rose, Denis Markovcheck, 

and Gerald Hoffman (USGS) for their field and laboratory contributions. 

BACKGROUND 

The BOR in cooperation with the City of Phoenix and the regional cities of Mesa, 

Tempe, Scottsdale, Youngtown, and Glendale, established the Phoenix Water Reclamation and 

Reuse Study in 1993 (CH2M Hill, 1995). The primary objective of the study was to identify 

technologies to reclaim municipal wastewater effluent for beneficial use applications. The Tres 

Rios Wetlands were evaluated as a means of satisfying water quality and wildlife habitat 

enhancement goals in the region. The U.S. Army Corps of Engineers initially described the 

demonstration wetlands concept in an unpublished water resources report for Maricopa County 

(CH2M Hill, 1995). As a result, the BOR proposed a design for two wetland systems sustained 

by effluent from the 91st Avenue WWTP and discharging into the Salt River. In October 1993, 

the BOR released a report on the “Phoenix Water Reclamation and Reuse Study” which included 

the conceptual design of the Tres Rios Demonstration Wetlands (U.S. Bureau of Reclamation, 

1993). The City of Phoenix and BOR amended the original proposal to include research cells in 

March 1994. The wetland design and construction was finalized in spring 1995 and the initial 

planting and irrigation began in May 1995. In October 1995, full hydraulic control of the site 

began (CH2M Hill, 1997). 

SITE DESCRIPTION 

The Tres Rios Wetlands are located at the 91st Avenue WWTP near the Salt River in 

Maricopa County, Arizona. The facilities consist of 12 small-scale research cells and two largerscale demonstration wetlands systems: the Cobble and Hayfield sites that vary in size, layout, 

and operational conditions (fig. 1-1). This study was conducted at the two demonstration wetland 

sites, each consisting of two parallel basins with emergent vegetation and controlled flow 

conditions. The four wetlands polish nearly 7500 cubic meters per day (m3/day, about 2 million 

gallons per day) of advanced-secondary, activated-sludge treated, nitrified-denitrified, 

chlorinated wastewater discharged from the 91st Avenue WWTP. Each wetland has alternating 

internal shallow zones (emergent vegetation) and deep zones (open water) with the deep zones 

having a depth one-meter below the emergent marsh elevation. Effluent from the 91st Avenue 

WWTP is pumped to the Cobble and Hayfield sites and distributed via inlet splitter boxes. 

Wetland operators control average detention times ranging from three to seven days with depths 

of 0.1 to 0.5 meters (m). During the course of this investigation the wetlands underwent periodic 

reconstruction, thus altering configuration, operation, and treatment (City of Phoenix, 1998; 

Wass, Gerke and Associates, 2001). All of the wetlands can be operated at similar conditions to 

compare design features on treatment efficiencies. 

HAYFIELD SITE 

The Hayfield site (fig. 1-2) consists of two free-water-surface constructed wetlands with 

each being approximately 228 m long and 60 m wide, and covering 1.4 hectares (ha) (CH2M 

Hill, 1997; Wass, Gerke and Associates, 2001). The two Hayfield wetlands (H1 and H2) were 

constructed on a former agricultural field. The H1 wetland has five internal sinusoidal deep 

6
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

zones and the H2 wetland has two interior deep zones. Although configured differently, both 

wetlands had approximately 20% deep water and 80% shallow emergent marsh zones. Several 

nesting islands are located in the H2 deep zones. The Hayfield wetlands are operated in parallel, 

and effluent from the two wetlands is combined and discharged into the Salt River channel. 

Figure 1-1. Site location and aerial photograph of the 91st Avenue Wastewater Treatment Plant and Tres 

Rios Treatment Wetlands. 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

COBBLE SITE 

The Cobble Site (fig. 1-3) consists of 2 free-water-surface constructed wetlands with each 

measuring approximately 275 m long and 35 m wide, and covering 0.96 ha (CH2M Hill, 1997; 

Wass, Gerke and Associates, 2001). The Cobble wetlands (C1 and C2) are built on the Salt River 

alluvial channel. The coarse cobble sediments allow significant leakage from the unlined C1 

wetland. The C2 wetland is lined with 2 to 4 centimeter (cm) of loamy topsoil from a nearby 

agricultural field to curtail water losses due to infiltration. During the course of most of this 

study, the C1 wetland contained mainly open water with little vegetation, whereas the C2 

wetland was fully vegetated. Effluent from the Cobble wetlands empties into the 91st Avenue 

WWTP discharge channel. 

Figure 1-2. Hayfield wetlands site map. [HS, Hayfield site; H1, Hayfield 1 wetland; H2, Hayfield 2 

wetland; DZ, deep zone] 

8
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

ECOSYSTEM 

The Tres Rios Wetlands provide habitat for numerous species of indigenous and 

migratory birds. Shallow open water zones support wading bird and waterfowl habitat while 

dense vegetation attracts passerine species. Biological diversity of the wetland basins at Tres 

Rios also includes fish, mammal, and macroinvertebrate species. Tilapia (Tilapia mossambica) 

are large, hardy fish that inhabit deep, open water areas and feed on algae. Mosquito fish 

(Gambusia affinis) are small fish that live in shallow vegetated areas and feed off mosquito 

larvae and other zooplankton. Mammals such as beaver and muskrats reside in the wetland 

basins. 

Plant species inhabiting the wetland basins include both emergent and floating aquatic 

vegetation. Emergent plants are rooted, vascular species that grow above the water surface in the 

shallow zones. The major emergent vegetation species are softstem bulrush (Schoenoplectus 

tabernaemontai) and Olney’s (three-square) bulrush (Schoenoplectus americanus). Floating 

aquatic plants occur in the deep zones and include both rooted and non-rooted vascular plants 

that have some parts, typically chlorophyll-bearing leaves, floating on the surface. Floating 

aquatic vegetation consisted primarily of duck weed (Lemna spp.) and water pennywort 

(Hydrocotyle spp.). 

Figure 1-3. Cobble wetlands site map. [CS, Cobble site; C1, Cobble 1 wetland; C2, Cobble 2 wetland; 

DZ, deep zone] 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

CHAPTER 2 - SAMPLING APPROACH 

 Samples were collected over a three-year period (1998 to 2000) at the Tres Rios 

Wetlands to provide field data on biota contaminant concentrations and wetland removal 

pathways. Tables 2-1, 2-2, and 2-3 summarize the field sampling efforts. Water analysis 

provided details on aqueous pollutant levels existing in the wetland habitat. Fish tissue and 

SPMD samples provide insight into bioconcentration processes occurring within the treatment 

basins. Sediment and bulrush analysis depict alternate removal processes of HOC and trace 

elements in the constructed wetlands. 

FIELD SAMPLING METHODS 

WATER 

Water samples were collected between 1998 and 2000 at each wetland inlet and outlet 

structure to detail long-term wastewater profiles. During 1998, Hydrolab MiniSonde 4A data 

collection platforms were positioned near the H2 inlet and outlet (approximately 0.5 m below 

water surface) to monitor conductivity, pH, temperature, and dissolved oxygen (DO) levels at 

one-hour intervals over a one-month period. Additional water samples were collected at the 91st

Avenue Outfall, 115th Avenue (5 kilometers, km, downstream), and Bullard Avenue (12 km 

downstream) along the Salt/Gila River to monitor water quality downstream of the wetlands and 

at the treatment plant discharge point. The Salt River becomes known as the Gila River 

immediately downstream of 115th Avenue. 

Water samples were collected in cleaned and burned one liter (L) amber glass bottles for 

analysis of total organic carbon (TOC), dissolved organic carbon (DOC), select pesticides, 

ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), nonylphenol 

ethoxycarboxylates (NPEC), and a suite of wastewater-derived compounds including 

nonylphenol and caffeine. Each bottle was rinsed three times with sample before filling and 

preserving on ice for shipping. Samples for EDTA, NTA, and NPEC were preserved with 1% 

(volume/volume, v/v) formalin. In February 2000, samples were collected in each deep zone of 

the H1 wetlands for analysis of volatile organic compounds (VOC). The samples were collected 

in pre-cleaned 40 milliliter (mL) amber-glass vials with no headspace to prevent losses from the 

aqueous phase, and preserved by addition of hydrochloric acid and ascorbic acid. Samples were 

shipped on ice and stored at 4 degrees Celsius (°C) until analysis. 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 2-1. Tres Rios Wetlands field sampling events, 1998. [H2, Hayfield 2 wetland; SPMD, 

semipermeable membrane device] 

Date Location Field Sampling 

July 23, 1998 H2 Wetland Tilapia and Gambusia Collection 

July 24, 1998 H2 Inlet Sediment samples collected 

 “ H2 Inlet Hydrolab deployed 

 “ H2 Inlet SPMD deployed 

 “ H2 Inlet Water samples collected 

 “ H2 Outlet Sediment samples collected 

 “ H2 Outlet Hydrolab deployed 

 “ H2 Outlet SPMD deployed 

 “ H2 Outlet Water samples collected 

 “ Bullard Avenue SPMD deployed 

 “ Bullard Avenue Water samples collected 

July 28, 1998 H2 Inlet Water samples collected 

 “ H2 Outlet Water samples collected 

August 4, 1998 H2 Inlet Water samples collected 

 “ H2 Outlet Water samples collected 

August 10, 1998 H2 Inlet Water samples collected 

 “ H2 Outlet Water samples collected 

August 18, 1998 H2 Inlet Water samples collected 

 “ H2 Outlet Water samples collected 

August 21, 1998 H2 Inlet SPMD removed and shipped 

 “ H2 Inlet Hydrolabs retrieved 

 “ H2 Inlet Water samples collected 

 “ H2 Outlet SPMD removed and shipped 

 “ H2 Outlet Hydrolabs retrieved 

 “ H2 Outlet Water samples collected 

 “ Bullard Avenue SPMD removed and shipped 

 “ Bullard Avenue Water samples collected 

Table 2-2. Tres Rios Wetlands field sampling events, 1999. [H1, Hayfield 1 wetland; C2, Cobble 2 

wetland; SPMD, semipermeable membrane device] 

Date Location Field Sampling 

June 21, 1999 H1 Inlet Water samples collected 

June 22, 1999 H1 Inlet Water samples collected 

 “ H1 Outlet Water samples collected 

June 23, 1999 C2 Inlet Sediment samples collected 

 “ C2 Inlet Schoenoplectus samples collected 

 “ C2 Outlet Sediment samples collected 

 “ C2 Outlet Schoenoplectus samples collected 

 “ 115th

 Avenue Water samples collected 

 “ Bullard Avenue Water samples collected 

June 24, 1999 H1 Inlet Five duplicate SPMD deployed 

 “ H1 Outlet Five duplicate SPMD deployed 

July 1, 1999 H1 Inlet Duplicate SPMD set 1 removed and shipped 

 “ H1 Outlet Duplicate SPMD set 1 removed and shipped 

July 8, 1999 H1 Inlet Duplicate SPMD set 2 removed and shipped 

 “ H1 Outlet Duplicate SPMD set 2 removed and shipped 

July 22, 1999 H1 Inlet Duplicate SPMD set 3 removed and shipped 

 “ H1 Outlet Duplicate SPMD set 3 removed and shipped 

August 5, 1999 H1 Inlet Duplicate SPMD set 4 removed and shipped 

 “ H1 Outlet Duplicate SPMD set 4 removed and shipped 

August 19, 1999 H1 Inlet Duplicate SPMD set 5 removed and shipped 

 “ H1 Outlet Duplicate SPMD set 5 removed and shipped 

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 2-3. Tres Rios Wetlands field sampling events, 2000. [H1, Hayfield 1 wetland; H2, Hayfield 2 

wetland; C1, Cobble 1 wetland; C2, Cobble 2 wetland; VOC, volatile organic compounds] 

Date Location Field Sampling 

February 13, 2000 Bullard Avenue Water samples collected 

 “ 115th Avenue Water samples collected 

February 14, 2000 Cobble Inlet Water samples collected 

 “ C1 Outlet Water samples collected 

 “ C2 Outlet Water samples collected 

 “ H1 Wetland Tilapia collected 

 “ Cobble Wetlands Gambusia collected 

February 15, 2000 Hayfield Inlet Water samples collected 

 “ H1 Outlet Water samples collected 

 “ H2 Outlet Water samples collected 

February 16, 2000 91st Ave Dewatering Well Water samples collected 

 “ H1 Wetland VOC water samples collected 

Samples were collected for determination of major ion water chemistry (anions and 

cations), trace elements (including mercury, Hg), and selected nutrients. A sample from each site 

was collected in an acid-rinsed Teflon (polytetrafluoroethylene - PTFE) holding bottle and an 

acid-rinsed glass holding bottle, which were shipped on ice to the USGS laboratory in Boulder, 

Colorado. Each bottle was rinsed a minimum of three times with sample prior to filling. Upon 

arrival at the laboratory, metals samples were immediately filtered through 47 millimeter (mm) 

diameter, 0.4 micrometer (μm) pore size polycarbonate membrane filters (Nuclepore #111107) in 

a PTFE filter holder under ultraclean conditions (Kelly and Taylor, 1996). Samples were 

collected in pre-cleaned high-density polyethylene bottles and preserved by the addition of highpurity distilled nitric acid (Kuehner and others, 1972) for trace-metals analysis. A filtered 

subsample for anion analysis was retained without acidification and preserved by chilling. 

Samples for Hg analysis were filtered from the glass holding bottle, collected in pre-cleaned 

borosilicate glass bottles with PTFE lined screw caps, and preserved with a mixture of highpurity nitric acid and high-purity potassium dichromate. Samples for nutrient analysis (nitrate, 

nitrite, ammonium, and phosphate) were collected in precleaned brown polyethylene bottles and 

stored at 4 o

C. 

FISH 

Tilapia and Gambusia were collected in 1998 and 2000 to investigate bioconcentration 

effects. The fish were caught by throw net (Tilapia) or scoop net (Gambusia), weighed, 

measured, examined, and preserved on dry ice. The Gambusia and Tilapia specimens were 

stored in aluminum foil for HOC analysis pesticide detection and plastic bags for trace-element 

analysis. Samples were stored frozen (-20 o

C) until further processing and analysis. 

SEMIPERMEABLE MEMBRANE DEVICES 

Semipermeable membrane devices (SPMD) are in-situ samplers that mimic uptake of 

HOC into the fatty tissues of aquatic organisms by passive diffusion of organic molecules 

through a synthetic membrane into lipid material (Huckins and others, 1996). Contaminant 

concentrations in the SPMD represent bioavailable compounds present in aquatic habitats. 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Although HOC that rapidly partition into SPMD exhibit similar behavior in aquatic organisms, 

the SPMD concentrate chemicals that can be metabolized or excreted by fish. As a result, the 

number of compounds sequestered by SPMD and their concentrations can be larger than those 

found in native fish tissue. In addition, SPMD provide time-integrated concentrations by 

sampling large volumes of water over several weeks accounting for hourly and daily fluctuations 

in flow and composition. 

Figure 2-1 shows the design of a typical SPMD and illustrates compound partitioning 

into the polyethylene tubing and diffusion through transport corridors into the triolein lipid. 

Local concentration gradients and physicochemical properties govern the rate of uptake into the 

sampling device. Semipermeable membrane devices primarily sequester dissolved organic 

molecules with some degree of conformational freedom and not limited by steric or solubility 

factors. Very large molecules may encounter transport resistance across both synthetic and 

biological membranes. Each SPMD is coiled across a metal deployment rack and placed inside a 

metal protective shroud. The containment structure protects the SPMD from damage, and can 

hold five SPMD deployment racks that can be combined to create a composite sample or 

analyzed individually. The SPMD used in this study were purchased from Environmental 

Sampling Technologies (EST, St Joseph, Missouri) in the standard design (Huckins and others, 

1996) with a triolein/membrane ratio (weight/weight, w/w) of ≈ 0.2, a low-density polyethylene 

membrane thickness of 75 to 90 μm, and a membrane surface area/lipid volume ratio of ≈ 450 

cubic centimeters per milliliter (cm2

/mL). 

During the 1998 field study, SPMD were deployed for 28 days at the H2 inlet and outlet 

to investigate the relative removal of bioavailable compounds through the wetland. Additional 

samplers were placed in the Salt River at the Bullard Avenue location to evaluate the presence of 

HOC at a downstream location. At each site, duplicate sets of five SPMD were transferred from 

sealed metal cans into the containment devices and then submerged at approximately the 

midpoint of the water column (≈ 0.5 m below water surface). No reference compounds were 

used in field exposures but similar flow and temperature regimes existed at both inlet and outlet 

locations allowing for intersite comparisons. At the conclusion of the 28-day deployment, the 

SPMD were recovered, immediately sealed in the original metal cans, and shipped on ice to EST. 

A trip blank accompanied the SPMD during shipment, deployment, and recovery. The blank was 

exposed to the atmosphere during deployment and recovery of the SPMD at each location and 

then resealed in the metal can and shipped for processing with the field samples. 

During 1999, a SPMD time-course study was conducted in the H1 wetland over an eightweek period. Duplicate deployment structures, containing five SPMD each, were placed near the 

inlet and outlet structures in the wetland. A duplicate set of SPMD was retrieved from each inlet 

and outlet location after the first week and then approximately every two weeks throughout the 

field survey. Trip blank SPMD were exposed to the atmosphere during the deployment and 

retrieval of samplers at each site. The field and trip blank SPMD were sealed in metal cans, 

preserved in ice, and shipped to EST for processing. 

SEDIMENT 

Composite (5 subsamples) sediment samples were collected along transects across the 

inlets and outlets of the H2 and C2 wetlands during 1998 and 1999 to examine HOC and trace 

elements associated with the wetland soils. Sediment samples from a depth of 5 to 10 centimeters 

14
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

(cm) were obtained using a polyvinyl chloride coring device, and placed in 500-mL, widemouthed amber glass jars. The samples were shipped on ice and frozen until analysis. 

VEGETATION 

Composite vegetation samples were collected from near the inlets and outlets of the 

Hayfield 2 and Cobble 2 wetlands during 1999 for trace element analysis. Schoenoplectus 

tabernaemontani and Schoenoplectus americanus samples were collected by hand pulling the 

whole plants. Samples were placed in plastic bags, shipped on ice, and frozen for trace element 

analysis. 

Figure 2-1. Semipermeable membrane device partitioning and containment structure (after Huckins and 

others, 1996). 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

ANALYTICAL METHODS

WATER 

Field Measurements

 Temperature, specific conductance, pH, and dissolved oxygen measurements were made 

at the time of sample collection. Specific conductance was measured using a temperature 

compensated conductivity meter (Orion 124) calibrated daily against USGS standard reference 

solutions. Dissolved oxygen was measured using a temperature and pressure compensated DO 

meter (Orion 820) that was calibrated daily against air. Sample pH was measured using an Orion 

250 Meter and 9107 Triode pH electrode. The electrode was calibrated daily using pH 4, 7, and 

10 standards. 

Total and Dissolved Organic Carbon 

Total and dissolved organic carbon analysis was performed using a Sievers Model 800 

Total Organic Carbon Analyzer. The instrument measures total carbon (TC) and total inorganic 

carbon (TIC), determining TOC by difference. Ammonium persulfate and phosphoric acid are 

added to the sample. The low pH converts TIC to carbon dioxide (CO2). The TC in the sample is 

subjected to ultraviolet (UV) radiation that in the presence of the persulfate oxidant breaks down 

organic carbon in the sample to form CO2. The CO2 partitions across a selectively permeable 

membrane into deionized water and is measured as bicarbonate ion by conductivity detector. 

Ultraviolet light absorbance of the filtered water samples was measured at 254 

nanometers (nm) to determine aromaticity, an indication of the humic and fulvic acid 

contribution to the total DOC (Thurman, 1985; Chin and others, 1994; Sartoris and others, 2000; 

Barber and others, 2001). Absorbance was measured in a 1-cm quartz cell using a Bausch and 

Lomb Spectronics Model 710 spectrophotometer. A 5 milligram (mg) carbon per liter Suwannee 

River Fulvic acid (Averett and others, 1989) solution was used as a reference standard. 

Pesticides

 Water samples were analyzed by USGS National Water Quality Laboratory (NWQL) 

Schedule 2001 for a variety of pesticide compounds (table 2-4) as described by Zaugg and others 

(1995). Water samples were filtered through 0.7-μm glass-fiber filters, extracted using 

octadecyl-bonded porous silica (C18) solid phase extraction (SPE) cartridges, and eluted with 

methylene chloride. The SPE extracts were analyzed by electron impact gas 

chromatography/mass spectrometry (GC/MS) in the selected ion monitoring (SIM) mode. The 

SPE extracts were analyzed by negative chemical ionization (NCI) GC/MS for organochlorine 

compounds. 

Herbicides 

 Water samples were analyzed for herbicides, insecticides, and associated metabolites 

(tables 2-5, 2-6, and 2-7) as described by Zimmerman and Thurman (1999). Compounds were 

16
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

extracted from filtered water samples by C18 SPE followed by elution with ethyl acetate. Target 

compounds were identified and quantified by SIM-GC/MS. Surrogate and internal standards 

were used to determine the concentrations and evaluate method performance. The method 

detection limit was approximately 5 micrograms per liter (μg/L). 

Volatile Organic Compounds

Water samples were analyzed for VOC (table 2-8) by NWQL Schedule 2020 (86 

compounds) and Schedule 2022 (35 compounds) as described in Connor and others (1998). 

Laboratory reporting limits are given for each compound and ranged from 0.03 to 7.1 μg/L. A 

Tekmar Model LSC 2000 concentrator with a Tekmar Aquatek autosampler purge and trap unit 

was used to sparge helium gas through a 25-mL aliquot of environmental sample. A VOCARB 

3000 trap containing 10 cm of Carbopak B (60/80 mesh), 6 cm of Carboxen (60/80 mesh), and 1 

cm of Carboxen 1001 (60/80 mesh) was used to trap the VOC. The compounds were thermally 

desorbed into a megabore capillary column interfaced with a GC/MS equipped with sub-ambient 

GC oven-cooling and a jet separator. The VOC concentrations were identified using standard 

reference materials and comparing retention times and ion ratios of the mass spectra. 

Wastewater-Derived Compounds

 Alkylphenols and other wastewater-derived compounds (table 2-9) were determined as 

described in Barber and others (2000). This method uses continuous liquid-liquid extraction 

(CLLE) with methylene chloride at pH 2 to continually expose a sample to solvent for an 

extended period by refluxing the solvent. The solvent is dispersed through a coarse-glass frit 

resulting in formation of micro-droplets that travel through the sample matrix. After extraction, 

the solvent is passed through a sodium sulfate drying column and the volume reduced to 500 

microliter (μL). The extracts were analyzed by GC/MS in both the full scan and SIM modes. 

Surrogate standards were added to the sample prior to extraction to evaluate method 

performance. 

Ethylenediaminetetraacetic, Nitrilotriacetic, and Nonylphenolethoxycarboxylic Acids

Ethylenediaminetetraacetic acid, NTA, and NPEC (table 2-10) were measured as the 

propyl esters (Barber and others, 2000) using a modification of the method of Schaffner and 

Giger (1984). Samples were spiked with d12-EDTA, evaporated to dryness, acidified with formic 

acid:distilled water (1:1 v/v), and evaporated to dryness again. Acetyl chloride:propanol (1:10 

v/v) was added, the sample heated to 85 oC for 1 hour (hr), and the esters extracted into 

chloroform. The extracts were evaporated and redissolved in toluene. Analysis for the propyl 

ester derivatives was by GC/MS in the full scan and SIM modes. 

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Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 2-4. Forty-eight pesticide compounds determined by USGS NWQL Schedule 2001. [CAS Number, 

Chemical Abstract Services registry number; LRL, laboratory reporting level; μg/L, microgram per liter] 

Compound CAS Number 

 LRL 

(μg/L) 

Acetochlor 34256-82-1 0.004 

Alachlor 15972-60-8 0.002 

Atrazine 1912-24-9 0.007 

Azinphos-methyl 86-50-0 0.050 

Benfluralin 1861-40-1 0.010 

Butylate 2008-41-5 0.002 

Carbaryl 63-25-2 0.040 

Carbofuran 1563-66-2 0.020 

Chlorpyrifos 2921-88-2 0.005 

Cyanazine 21725-46-2 0.018 

1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) 72-55-9 0.003 

Dacthal 1861-32-1 0.003 

Deethylatrazine 6190-65-4 0.006 

Diazinon 333-41-5 0.005 

Dieldrin 60-57-1 0.005 

2,6-Diethylaniline 579-66-8 0.002 

Disulfoton 298-04-4 0.020 

S-Ethyldipropylthiocarbamate 759-94-4 0.002 

Ethalfluralin 55283-68-6 0.009 

Ethoprophos 13194-48-4 0.005 

Fonofos 944-22-9 0.003 

alpha-Hexachlorohexane 319-84-6 0.005 

gamma-Hexachlorohexane (lindane) 58-89-9 0.004 

Linuron 330-55-2 0.035 

Malathion 121-75-5 0.027 

Metolachlor 51218-45-2 0.013 

Metribuzin 21087-64-9 0.006 

Molinate 2212-67-1 0.002 

Napropamide 15299-99-7 0.007 

Parathion 56-38-2 0.007 

Parathion-methyl 298-00-0 0.006 

Pebulate 1114-71-2 0.002 

Pendimethalin 40487-42-1 0.010 

cis-Permethrin 54774-45-7 0.006 

Phorate 298-02-2 0.011 

Prometon 1610-18-0 0.015 

Propachlor 1918-16-7 0.010 

Propanil 709-98-8 0.011 

Propargite 2312-35-8 0.023 

Propyzamide 23950-58-5 0.004 

Simazine 122-34-9 0.011 

Tebuthiuron 34014-18-1 0.016 

Terbacil 5902-51-2 0.034 

Terbufos 13071-79-9 0.017 

Terbuthylazine 5915-41-3 0.100 

Thiobencarb 28249-77-6 0.005 

Tri-allate 2303-17-5 0.002 

Trifluralin 1582-09-8 0.009 

Surrogate Standards 

Diazinon-d10 100155-47-3 0.100 

alpha-Hexachlorohexane-d6 86194-41-4 0.100 

18
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 2-5. Twenty-six herbicide compounds measured in water by the USGS Lawrence, Kansas 

laboratory. [CAS Number, Chemical Abstract Services registry number; MDL, method detection limit; 

μg/L, microgram per liter; NA, not available] 

Compound CAS Number 

 MDL 

(μg/L) 

Acetochlor 34256-82-1 0.05 

Alachor 15972-60-8 0.05 

Atrazine 1912-24-9 0.05 

Cyanazine 21725-46-2 0.05 

Cyanazine-amide 36576-42-8 0.05 

Deethylatrazine 6190-65-4 0.05 

Deisopropylatrazine 1007-28-9 0.05 

Deisopropylprometryn NA 0.05 

Demethylfluometurn NA 0.20 

Demethylnorfluorazon NA 5 

3,4-Dichloroaniline 95-76-1 5 

Diuron 330-54-1 0.20 

Fluometuron 2164-17-2 0.20 

Linuron 330-55-2 0.20 

Metolachlor 51218-45-2 0.05 

Metribuzin 21087-64-9 5 

Molinate 2212-67-1 5 

Norfluorazon 27314-13-2 5 

Pendimethalin 40487-42-1 5 

Prometryn 7287-19-6 5 

Propanil 709-98-8 5 

Propazine 139-40-2 0.05 

Simazine 122-34-9 0.05 

Trifluralin 1582-09-8 5 

Trifluromethyl-aniline 9898-16-8 5 

Trifluromethyl phenyl urea 13114-87-9 5 

Major Cations and Trace Elements 

Major ions present at relatively high (milligram per liter, mg/L) concentration levels 

(including calcium, Ca, magnesium, Mg, sodium, Na, and iron, Fe) were determined by 

inductively coupled plasma/atomic emission spectrometry (ICP/AES) techniques using a Perkin 

Elmer Optima 3300, dual view emission spectrometer operating in the radial view mode. A 

description of the analysis conditions and general procedures for this methodology are reported 

by Garbarino and Taylor (1979). Potassium was also determined by ICP/AES using the same 

instrument operating in the axial-view mode. Samples were analyzed in triplicate to provide a 

measure of the variability of the analysis. 

Trace-element determinations (excluding Hg) were performed with a Perkin Elmer Elan 

Model 6000, inductively coupled plasma/mass spectrometer (ICP/MS). Aerosols of nitric acid 

acidified aqueous samples were introduced into the spectrometer with a cone-spray pneumatic 

nebulizer. Multiple internal standards (indium, iridium, and rhodium), covering the entire mass 

range were used to normalize the system for drift. Details of the analysis are described elsewhere 

(Garbarino and Taylor, 1995; Taylor, 2001). Samples were analyzed in triplicate to provide a 

measure of the variability of the analysis. Specific trace elements measured for the individual 

sample matrices (water, sediment, biota) and their average detection limits are shown in tables 2-

11 to 2-14. 

19
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 2-6. Twenty-three insecticide compounds measured in water by the USGS Lawrence, Kansas 

laboratory. [CAS Number, Chemical Abstract Services registry number; MDL, method detection limit; 

μg/L, microgram per liter] 

Compound CAS Number 

 MDL 

(μg/L) 

Aldrin 309-00-2 0.05 

Azinphos-methyl 85-50-0 0.05 

Bifinthrin 82657-04-03 0.05 

Chlordane 57-74-9 0.05 

Chlorpyriphos 2921-88-2 0.05 

Cyfluthrin 68359-37-5 0.05 

L-Cyhalothrin 68085-85-8 0.05 

Cypermethrin 52315-07-8 0.05 

1,1-Dichloro-2,2-bis(p-chlorophenyl)ethane (p,p’-DDD) 72-54-8 0.05 

p,p’-DDE 72-55-9 0.05 

1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane (p,p’-DDT) 50-29-3 0.05 

Dicrotophos 141-66-2 0.05 

Dieldrin 60-57-1 0.05 

Endosulfan 115-29-7 0.05 

Endrin 72-20-8 0.05 

Fonofos 944-22-9 0.05 

Heptachlor 76-44-8 0.05 

Malathion 121-75-5 0.05 

Methyl parathion 298-00-0 0.05 

Permethrin 52645-53-1 0.05 

Profenos (Profenofos) 41198-08-7 0.05 

Sulprofos 35400-43-2 0.05 

Terbufos 13071-79-9 0.05 

Table 2-7. Seven herbicide metabolites measured in water by the USGS Lawrence, Kansas laboratory. 

[CAS Number, Chemical Abstract Services registry number; MDL, method detection limit; μg/L, 

microgram per liter; ESA, ethane sulfonic acid; NA, not available] 

Compound CAS Number 

 MDL 

(μg/L) 

Acetochlor ESA NA 0.05 

Acetochlor oxanilic acid NA 0.05 

Alachlor ESA NA 0.05 

Alachlor oxanilic acid NA 0.05 

Hydroxyatrazine 2163-68-0 0.05 

Metolachlor ESA NA 0.05 

Metolachlor oxanilic acid NA 0.05 

20
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 2-8. Eighty-six volatile organic compounds measured in water by USGS NWQL Schedule 2020 

and 35 compounds measured by Schedule 2022. [CAS Number, Chemical Abstract Services registry 

number; LRL, laboratory reporting level; μg/L, microgram per liter; NA, not available] 

Compound CAS Number 

 LRL 

(μg/L) 

Acetone 67-64-1 7.10 

Acrylonitrile 107-13-1 1.20 

Benzenea 71-43-2 0.04 

Bromobenzene 108-86-1 0.04 

Bromochloromethane 74-97-5 0.04 

Bromodichloromethanea 75-27-4 0.05 

Bromoforma 75-25-2 0.06 

Bromomethane 74-83-9 0.26 

2-Butanone 78-93-3 1.60 

normal-Butylbenzene 104-51-8 0.19 

sec-Butylbenzene 135-98-8 0.03 

tert-Butylbenzene 98-06-6 0.06 

tert-Butyl ethyl ethera 637-92-3 0.05 

tert-Butyl methyl ether (MTBE) a 1634-04-4 0.17 

Carbon disulfide 75-15-0 0.07 

Chlorobenzenea 108-90-7 0.03 

Chloroethane 75-00-3 0.12 

Chloroforma 67-66-3 0.05 

Chloromethane 74-87-3 0.50 

3-Chloropropene 107-05-1 0.20 

2-Chlorotoluene 95-49-8 0.04 

4-Chlorotoluene 106-43-4 0.06 

Dibromochloromethanea 124-48-1 0.18 

1,2-Dibromo-3-chloropropane 96-12-8 0.21 

1,2-Dibromoethane 106-93-4 0.04 

Dibromomethane 74-95-3 0.05 

1,2-Dichlorobenzenea 95-50-1 0.05 

1,3-Dichlorobenzenea 541-73-1 0.05 

1,4-Dichlorobenzenea 106-46-7 0.05 

trans-1,4-Dichloro-2-butene 110-57-6 0.70 

Dichlorodifluoromethanea 75-71-8 0.27 

1,1-Dichloroethanea 75-34-3 0.07 

1,2-Dichloroethanea 107-06-2 0.13 

1,1-Dichloroethenea 75-35-4 0.04 

cis-1,2-Dichloroethenea 156-59-2 0.04 

trans-1,2-Dichloroethenea 156-60-5 0.03 

1,2-Dichloropropanea 78-87-5 0.07 

1,3-Dichloropropane 142-28-9 0.12 

2,2-Dichloropropane 594-20-7 0.05 

1,1-Dichloropropene 563-58-6 0.03 

cis-1,3-Dichloropropene 10061-01-5 0.09 

trans-1,3-Dichloropropene 10061-02-6 0.09 

Diethyl ethera 60-29-7 0.17 

Diisopropyl ethera 108-20-3 0.10 

Ethylbenzenea 100-41-4 0.03 

Ethyl methacrylate 97-63-2 0.18 

1,2-Ethyltoluene 611-14-3 0.06 

Hexachlorobutadiene 87-68-3 0.14 

Hexachloroethane 67-72-1 0.19 

2-Hexanone 591-78-6 0.70 

21
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 2-8. Continued. 

Compound CAS Number 

 LRL 

(μg/L) 

Isopropylbenzene 98-82-8 0.03 

1,4-Isopropyltoluene 99-87-6 0.07 

Methyl acrylate 96-33-3 1.40 

Methyl acrylonitrile 126-98-7 0.60 

Methylene chloridea 75-09-2 0.38 

Methyl iodide 74-88-4 0.12 

Methyl methacrylate 80-62-6 0.35 

4-Methyl-2-pentanone 108-10-1 0.37 

Naphthalene 91-20-3 0.25 

tert-Pentylmethyl ether 994-05-8 0.11 

normal-Propylbenzene 103-65-1 0.04 

Styrenea 100-42-5 0.04 

1,1,1,2-Tetrachloroethane 630-20-6 0.03 

1,1,2,2-Tetrachloroethane 79-34-5 0.09 

Tetrachloroethenea 127-18-4 0.10 

Tetrachloromethanea 56-23-5 0.06 

Tetrahydrofuran 109-99-9 2.20 

1,2,3,4-Tetramethylbenzene 488-23-3 0.23 

1,2,3,5-Tetramethylbenzene 527-53-7 0.20 

Toluenea 108-88-3 0.05 

1,2,3-Trichlorobenzene 87-61-6 0.27 

1,2,4-Trichlorobenzene 120-82-1 0.19 

1,1,1-Trichloroethanea 71-55-6 0.03 

1,1,2-Trichloroethane 79-00-5 0.06 

Trichloroethenea 79-01-6 0.04 

Trichlorofluoromethanea 75-69-4 0.09 

1,2,3-Trichloropropane 96-18-4 0.16 

1,1,2-Trichloro-1,2,2-trifluoroethanea 76-13-1 0.06 

1,2,3-Trimethylbenzene 526-73-8 0.12 

1,2,4-Trimethylbenzene 95-63-6 0.06 

1,3,5-Trimethylbenzene 108-67-8 0.04 

Vinyl bromide 593-60-2 0.10 

Vinyl chloridea 75-01-4 0.11 

1,3- and 1,4-Xylenea 108-38-3 and 106-42-3 0.06 

1,2-Xylenea 95-47-6 0.04 

Surrogate Standards 

1,4-Bromofluorobenzenea 460-00-4 NA 

1,2-Dichloroethane d4

a 17060-07-0 NA 

Toluene d8

a 2037-26-5 NA a

. VOC measured in both USGS NWQL Schedule 2020 and 2022. 

22
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 2-9. Forty wastewater-derived compounds measured in water by USGS Boulder, Colorado 

Laboratory. [CAS Number, Chemical Abstract Services registry number; MDL, method detection limit; 

μg/L, microgram per liter; NA, not available] 

Compound CAS Number 

 MDL

(μg/L)

cis-Androsterone 53-41-8 0.01

Bisphenol A 80-05-7 0.01

2[3]-tert-Butyl-4-methoxyphenol 25013-16-5 0.01

4-tert-Butylphenol 98-54-4 0.01

Caffeine 58-08-2 0.01

Cholesterol 57-88-5 0.01

3-beta-Coprostanol 360-68-9 0.01

2,6-Di-tert-butyl-1,4-benzoquinone 719-22-2 0.01

2,6-Di-tert-butyl-4-methylphenol 128-37-0 0.01

2,6-Di-tert-butylphenol 128-39-2 0.01

1,2-Dichlorobenzene 95-50-1 0.01

1,3-Dichlorobenzene 541-73-1 0.01

1,4-Dichlorobenzene 106-46-7 0.01

Equilenin 517-09-9 0.01

Equilin 474-86-2 0.01

17-alpha-Estradiol 57-91-0 0.01

17-beta-Estradiol 50-28-2 0.01

Estriol 50-27-1 0.01

Estrone 53-16-7 0.01

4-Ethylphenol 123-07-9 0.01

17-alpha-Ethynylestradiol 57-63-6 0.01

Mestranol 72-33-3 0.01

4-Methylphenol 106-44-5 0.01

4-Nonylphenol 25154-52-3 0.01

4-Nonylphenolmonoethoxylate 9016-45-9 0.01

4-Nonylphenoldiethoxylate NA 0.01

4-Nonylphenoltriethoxylate NA 0.01

4-Nonylphenoltetraethoxylate NA 0.01

19-Norethisterone 68-22-4 0.01

4-normal-Octylphenol 1806-26-4 0.01

4-tert-Octylphenol 140-66-9 0.01

4-tert-Octylphenolmonoethoxylate 9036-19-5 0.01

4-tert-Octylphenoldiethoxylate NA 0.01

4-tert-Octylphenoltriethoxylate NA 0.01

4-tert-Octylphenoltetraethoxylate NA 0.01

4-tert-Pentylphenol 80-46-6 0.01

Progesterone 57-83-0 0.01

4-Propylphenol 645-56-7 0.01

Testosterone 58-22-0 0.01

Triclosan 3380-34-5 0.01

Surrogate Standards 

Bisphenol A d6 86588-58-1 0.01

Cholesterol d7 NA 0.01

2,6-Di-tert-butyl-4-methylphenol d21 64502-99-4 0.01

17-beta-Estradiol d4 66789-03-5 0.01

4-normal-Nonylphenol 104-40-5 0.01

4-normal-Nonylphenolmonoethoxylate NA 0.01

4-normal-Nonylphenoldiethoxylate NA 0.01

23
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 2-10. Ethylenediaminetetraacetic acid, nitrilotriacetic acid, and nonylphenolethoxycarboxylic acid 

measured in water by USGS Boulder, Colorado Laboratory. [CAS Number, Chemical Abstract Services 

registry number; MDL, method detection limit; μg/L, microgram per liter; NA, not available] 

Compound CAS Number

 MDL

(μg/L)

Ethylenediaminetetraacetic acid 60-00-4 0.5

Nitrilotriacetic acid 139-13-9 0.5

4-Nonylphenolmonoethoxycarboxylate NA 0.5

4-Nonylphenoldiethoxycarboxylate 106807-78-7 0.5

4-Nonylphenoltriethoxycarboxylate NA 0.5

4-Nonylphenoltetraethoxycarboxylate NA 0.5

4-Nonylphenolpentaethoxycarboxylate NA 0.5

Surrogate Standards 

Ethylenediaminetetraacetic acid d12 203806-08-0 0.5

4-normal-Nonylphenoldiethoxycarboxylate NA 0.5

Table 2-11. Major ions and trace elements measured in water, their atomic symbols, and method 

detection limits (MDL). [μg/L, microgram per liter] 

Element

 MDL 

(μg/L) Element 

 MDL 

(μg/L) 

Aluminum (Al) 0.05 Magnesium (Mg) 15 

Arsenic (As) 0.04 Manganese (Mn) 0.02 

Boron (B) 4 Molybdenum (Mo) 0.03 

Barium (Ba) 0.01 Sodium (Na) 70 

Beryllium (Be) 0.02 Neodymium (Nd) 0.003 

Bismuth (Bi) 0.01 Nickel (Ni) 0.02 

Calcium (Ca) 20 Lead (Pb) 0.006 

Cadmium (Cd) 0.006 Praseodymium (Pr) 0.0005 

Cerium (Ce) 0.001 Rubidium (Rb) 0.002 

Cobalt (Co) 0.01 Rhenium (Re) 0.0013 

Chromium (Cr) 0.2 Antimony (Sb) 0.02 

Cesium (Cs) 0.06 Selenium (Se) 0.2 

Copper (Cu) 0.02 Silica (SiO2) 50 

Dysprosium (Dy) 0.002 Samarium (Sm) 0.003 

Erbium (Er) 0.002 Strontium (Sr) 0.02 

Europium (Eu) 0.001 Terbium (Tb) 0.0007 

Iron (Fe) 0.7 Thallium (Tl) 0.005 

Gadolinium (Gd) 0.003 Thulium (Tm) 0.0005 

Mercury (Hg) 0.0004 Uranium (U) 0.002 

Holmium (Ho) 0.0005 Vanadium (V) 0.05 

Potassium (K) 10 Yttrium (Y) 0.0004 

Lanthanum (La) 0.0005 Ytterbium (Yb) 0.0014 

Lithium (Li) 0.1 Zinc (Zn) 0.08 

Lutetium (Lu) 0.0005 Zirconium (Zr) 0.01 

24
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 2-12. Major ions and trace elements measured in fish tissue (dry weight basis) and method 

detection limits (MDL). [μg/g, microgram per gram] 

Element

 MDL 

(μg/g) Element 

 MDL 

(μg/g) 

Al 0.5 Mg 20 

As 0.05 Mn 0.2 

B 9 Mo 0.1 

Ba 0.07 Na 70 

Be 0.2 Nd 0.008 

Bi 0.005 Ni 0.2 

Ca 10 Pb 0.04 

Cd 0.07 Pr 0.003 

Ce 0.003 Rb 0.1 

Co 0.02 Re 0.004 

Cr 1 Sb 0.03 

Cs 1 Se 0.2 

Cu 0.01 SiO2 100 

Dy 0.002 Sm 0.005 

Er 0.008 Sr 0.1 

Eu 0.001 Tb 0.002 

Fe 5 Tl 0.05 

Gd 0.003 Tm 0.002 

Hg 0.006 U 0.006 

Ho 0.0005 V 0.5 

K 50 Y 0.003 

La 0.003 Yb 0.006 

Li 0.1 Zn 0.8 

Lu 0.001 Zr 0.01 

 Mercury stock and standard solutions were made from Puratronic grade (99.9995%) 

mercuric chloride (Johnson Mathey), and preserved in a solution of high-purity nitric acid and 

primary-standard grade potassium dichromate (4% v/v and 0.04% weight/volume, w/v, 

respectively). Deionized water (18 megaohm/cm) was used for preparing all standards and 

reagent solutions. A 2% w/v stannous chloride solution in 3% v/v trace-metal grade hydrochloric 

acid purged for 15 minutes with argon was used for the reduction of Hg to its elemental form in 

the cold-vapor reactor. Concentrations of Hg were measured using an automated, cold-vapor 

atomic fluorescence spectrometer (PS Analytical). Details of the method are described in Roth 

(1994) and Roth and others (2001). Elemental Hg vapor from the sample produced by 

chemically reducing Hg with excess stannous chloride was transported to the atomicfluorescence detector with a stream of argon gas. Peak height intensities of unknown samples 

were compared to a six-point calibration curve prepared from aqueous standards ranging in 

concentration from 0 to 50 nanograms per liter (ng/L). 

Anions 

 The determination of major anions including chloride and sulfate was completed on 

filtered samples by ion-exchange chromatography utilizing a Dionex model 2002i ion 

chromatograph. Detailed procedures are described in Brinton and others (1996). 

25
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 2-13. Major ions and trace elements measured in vegetation tissue (dry weight basis) and method 

detection limits (MDL). [μg/g, microgram per gram; --, major constituent and therefore MDL not 

determined] 

Element

 MDL 

(μg/g) Element 

 MDL 

(μg/g) 

Al 0.5 Mg -- 

As 0.05 Mn 0.1 

B 5 Mo 0.2 

Ba 0.1 Na -- 

Be 0.08 Nd 0.003 

Bi 0.01 Ni 0.03 

Ca -- Pb 0.02 

Cd 0.009 Pr 0.0004 

Ce 0.001 Rb 0.1 

Co 0.01 Re 0.001 

Cr 2 Sb 0.008 

Cs 0.3 Se 0.3 

Cu 0.01 SiO2 -- 

Dy 0.003 Sm 0.003 

Er 0.003 Sr 0.1 

Eu 0.001 Tb 0.0006 

Fe -- Tl 0.01 

Gd 0.002 Tm 0.0004 

Hg 0.005 U 0.003 

Ho 0.0004 V 0.3 

K -- Y 0.001 

La 0.0005 Yb 0.002 

Li 0.1 Zn 0.5 

Lu 0.0007 Zr 0.03 

Nutrients

 Filtered water samples were analyzed for nitrite, nitrate plus nitrite, ammonium, and 

orthophosphate using an air-segmented continuous flow analyzer (Alpkem RFA 300). Nitrate 

plus nitrite was determined colorimetrically at 543 nm by diazotization with sulfanilamide and 

reaction with N-(1-naphthyl)-ethylenediamine (Greiss reaction) after reduction of nitrate to 

nitrite with cadmium metal. Nitrite was determined by the same technique without cadmium 

reduction. Ammonium was determined colorimetrically at 660 nm by the salicylic acid analog of 

the indophenol blue method. Orthophosphate was determined colorimetrically at 880 nm by the 

phosphoantomonyl molybdenum blue method. Further details are available in Antweiler and 

others (1996). 

26
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 2-14. Major ions and trace elements measured in sediment samples (dry weight basis) and method 

detection limits (MDL). [μg/g, microgram per gram; --, major constituent and therefore MDL not 

determined] 

Element

 MDL 

(μg/g) Element 

 MDL 

(μg/g) 

Mg -- 

As 20 Mn 0.1 

Ba 1 Mo 0.1 

Be 0.09 Na -- 

Bi 0.01 Nd 0.1 

Ca -- Ni 0.1 

Cd 0.01 Pb 0.1 

Ce 0.1 Pr 0.1 

Co 0.11 Rb 0.1 

Cr 1 Re 0.002 

Cs 1 Sb 0.1 

Cu 0.1 Se 0.1 

Dy 0.1 Sm 0.1 

Er 0.1 Sr 0.1 

Eu 0.1 Tb 0.01 

Fe -- Tl 0.1 

Gd 0.1 Tm 0.01 

Hg 0.003 U 0.01 

Ho 0.01 V 0.1 

K -- Y 0.1 

La 0.1 Yb 0.01 

Li 0.1 Zn 0.5 

Lu 0.01 Zr 0.1 

FISH TISSUE AND SEMIPERMEABLE MEMBRANE DEVICES 

Tissue Processing 

Fish specimens were collected in 1998 (table 2-15) for whole-body, filet, liver, and other 

(bones, skin, organs other than liver) tissue analysis to obtain preliminary data on HOC and trace 

element concentrations. Individual Tilapia whole-body fish were dissected using stainless steel 

tools in a clean room environment to obtain the various fractions. Composite Gambusia wholebody and Tilapia whole-body, filet, and other tissue were homogenized for approximately three 

minutes using a stainless-steel blade in a tissue blender. Tilapia livers were homogenized by 

stirring with a Teflon probe for three minutes. The homogenized fish tissue samples were dried 

at 65 °C until a constant weight was achieved. 

 Additional Gambusia and Tilapia specimens were collected in 2000 for more detailed 

analysis of HOC and trace elements. Figure 2-2 shows a typical Tilapia specimen. Individual 

Tilapia were dissected in a laminar-flow hood using PTFE coated labware and ceramic knives 

and scissors (fig. 2-3). The filet tissue was separated from the skin and the bones were removed. 

The filet tissue was minced with the ceramic knife and homogenized. Livers from each specimen 

were removed using ceramic scissors. A portion of both the homogenized filet and liver tissue 

was oven-dried to determine percent moisture. After analysis, the percent moisture was used to 

compute trace-element concentrations on a dry-weight basis. Because of their small size 

Gambusia were treated as whole organisms (fig. 2-4). 

27
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Figure 2-2. Typical Tilapia specimen. 

Figure 2-3. Tilapia dissected with a ceramic knife. 

28
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 2-15. Data on fish tissue samples collected in 1998 and 2000 and analyzed for organochlorine 

compounds and trace elements. [--, not determined; ++, tissue sample collected but mass not determined] 

Sample Type 

Collection 

Date 

Length 

(mm) 

Height 

(mm) 

Whole 

Body 

(g) 

Filet 

(g) 

Liver 

(g) 

Other 

(g) 

Organic Analysis 

Tilapia Whole-Body1a 1998 162 -- 77.5 -- -- -- 

 “ 1998 176 -- 96.5 -- -- -- 

 “ 1998 148 -- 60.0 -- -- -- 

 “ 1998 166 -- 80.0 -- -- -- 

 “ 1998 147 -- 61.0 -- -- -- 

Tilapia Dissectiona 1998 145 -- 56.0 ++ ++ ++

 “ 1998 137 -- 44.5 ++ ++ ++

 “ 1998 165 -- 80.0 ++ ++ ++

 “ 1998 148 -- 57.0 ++ ++ ++

 “ 1998 162 -- 75.5 ++ ++ ++

Gambusia Whole-Bodya 1998 -- -- 118.5 -- -- -- 

Trace Element Analysis

Tilapia Whole-Body #1a 1998 285 -- 410.0 -- -- -- 

 “ 1998 274 -- 356.0 -- -- -- 

 “ 1998 177 -- 104.0 -- -- -- 

Tilapia Dissection #1a 1998 175 -- 89.0 ++ ++ ++ 

 “ 1998 151 -- 66.0 ++ ++ ++ 

Tilapia Whole-Body #2a 1998 138 -- 52.0 -- -- -- 

 “ 1998 141 -- 53.5 -- -- -- 

 “ 1998 138 -- 49.0 -- -- -- 

Tilapia Dissection #2a 1998 160 -- 75.5 ++ ++ ++ 

 “ 1998 139 -- 47.5 ++ ++ ++ 

Gambusia Whole-Bodya 1998 -- -- 44.5 -- -- -- 

Organic Analysis 

Tilapia Whole-Bodya 2000 210 73 150.8 -- -- -- 

 “ 2000 180 57 96.7 -- -- -- 

 “ 2000 209 68 140.7 -- -- -- 

 “ 2000 205 68 148.1 -- -- -- 

 “ 2000 210 67 102.6 -- -- -- 

Tilapia Dissectiona 2000 201 72 169.1 25.0 1.6 129.5 

 “ 2000 220 73 167.7 32.7 4.8 117.2 

 “ 2000 210 69 115.5 12.5 1.4 93.7 

 “ 2000 165 50 59.8 9.7 0.4 47.2 

 “ 2000 230 79 180.5 36.7 3.0 132.3 

Gambusia Whole-Bodya 2000 -- -- 59.2 -- -- -- 

Trace Element Analysis

Tilapia Dissectiona 2000 183 57 97.9 20.1 1.2 76.6b

 “ 2000 171 54 88.0 20.2 1.4 66.4 b

 “ 2000 174 61 100.9 15.6 0.4 84.9 b

 “ 2000 197 64 119.1 21.2 1.6 96.3 b

 “ 2000 220 74 164.2 30.3 1.8 132.1 b

 “ 2000 156 54 59.2 6.5 0.6 52.1 b

 “ 2000 177 58 90.1 15.4 0.4 74.3 b

 “ 2000 172 58 82.9 12.8 0.7 69.4 b

Gambusia Whole-Bodya 2000 -- -- 97.0 -- -- -- a

. Composite sample. 

b

. Value calculated by difference. 

29
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Figure 2-4. Numerous Gambusia specimens in holding jar. 

Organic Contaminants 

Fish Tissue 

Whole-body and filet tissue samples collected in 1998 (table 2-15) were prepared for 

HOC analysis by USGS NWQL Schedule 2101 (table 2-16) as described in Leiker and others 

(1995). A subset of five Tilapia collected in 2000 were dissected into filet, liver, and other parts, 

weighed, and frozen in amber glass jars. Well-mixed composite samples of homogenized whole 

body, filet, liver, and other fish tissues were mixed with granular anhydrous sodium sulfate. 

Aliquots of the homogenized tissue were Soxhlet extracted overnight with methylene chloride. 

The extract volume was reduced and a subsample removed to determine percent lipid 

concentration. The remaining extract was injected into a Waters Envirogel gel permeation 

chromatography (GPC) column to isolate target compounds from lipid material. The GPC 

extracts were fractionated into polar and nonpolar portions using alumina/silica adsorption 

chromatography. Each fraction was concentrated and analyzed by dual capillary-column gas 

chromatography with electron-capture detection. The method detection limits were 

approximately 5 micrograms per kilogram (μg/kg). 

30
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Semipermeable Membrane Devices 

The SPMD were stored in sealed metal cans in a freezer until processed by EST in a 

clean room where the exterior periphyton and algal biomass was removed by scrubbing with a 

nylon brush followed by an acid rinse. HOC residues were recovered by dialysis in hexane and 

further enriched by GPC. The GPC fractionated hexane extracts were reduced in volume to 

approximately 4 mL and ampulated. The SPMD extracts were further concentrated and analyzed 

for the same compounds as the fish tissue (table 2-16) by dual capillary-column gas 

chromatography with electron capture detection (Leiker and others, 1995), with additional 

analysis by NCI GC/MS for confirmation of compound identities. 

Trace Elements 

Fish Tissue 

Fish specimens were collected in 1998 (table 2-15) for trace element analysis (Hoffman, 

1996). Tissue samples were digested using concentrated nitric acid and 30% hydrogen peroxide. 

The digested samples were evaporated to near dryness and reconstituted with nitric acid, and 

insoluble material removed by filtration. Duplicate blank samples, each consisting of three 

Whatman filters wetted with 30 mL of deionized water, were homogenized and digested 

similarly to the fish samples to determine contaminants introduced by the homogenization 

process. Two additional blank filter samples were digested but not homogenized to identify 

contaminants in the filters. Two reagent blanks were taken through the digestion process for use 

as reference standards. 

Additional fish specimens were collected in 2000 for trace-element analysis. Samples 

were digested in closed PTFE vessels in a laboratory microwave oven using high purity nitric 

acid (Milestone, 1994). After digestion, samples were diluted to volume with 1% high-purity 

nitric acid. Blanks were processed using the same procedure. Samples were analyzed by the 

appropriate instrumental method (as described above) in triplicate and reported with an error 

term representing the standard deviation of replicate measurements. Accuracy was established 

using certified standard reference materials (SRM) from the National Research Council of 

Canada (NRC), and included SRM DORM-1 (Dogfish Muscle) and SRM DOLT-1 (Dogfish 

Liver). Detection limits for fish tissue determinations are reported in table 2-12. 

Vegetation Tissue 

 

Two species of rooted emergent plants were sampled; (1) softstem bulrush 

(Schoenoplectus tabernaemontani), and (2) Olney’s (three-square) bulrush (Schoenoplectus 

americanus). Whole plants were sampled in the field and transported to the laboratory. In the 

laboratory, culms from the bulrush specimens were dissected using a ceramic knife into 

subsamples along the entire length of the culm. The subsamples were composited and freezedried to remove moisture, followed by grinding with acrylic balls to insure homogeneity. 

31
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Portions of the freeze-dried sample were digested as described above with high purity nitric acid 

using a closed-vessel microwave oven procedure. Samples were analyzed by the appropriate 

instrumental method (described above) in triplicate and reported with an error term representing 

the standard deviation of replicate measurements. Accuracy of these analyses was established 

using National Institute of Standards and Technology (NIST) SRM Apple Leaves (SRM 1515). 

Digestion blanks also were analyzed. Analyses are reported on a dry-weight basis. Detection 

limits for the plant tissue determinations are reported in table 2-13. 

SEDIMENT 

Organic Contaminants 

Hydrophobic organic compounds in bottom sediment were determined by NWQL 

Schedule 2501 (table 2-16) as described in Furlong and others (1996). Wet sediment samples 

were weighed, centrifuged, and mixed with sodium sulfate to remove excess water. The sediment 

sample was then Soxhlet extracted overnight with methanol followed by methylene chloride, and 

the combined extracts dried over sodium sulfate. The extract volume was reduced and an aliquot 

was injected into a styrene-divinylbenzene GPC column and eluted with methylene chloride. 

Separate fractions were collected for organochlorine compounds and semi-volatile compounds. 

The semi-volatile fraction was exchanged into ethyl acetate and reduced in volume. Target 

analytes were identified by GC/MS, and quantitation was performed using internal standards and 

a multiple-point calibration curve. 

Trace Elements

 Sediment samples were thawed and homogenized prior to subsampling wet. Subsamples 

were removed for both digestion and percent moisture determinations. Total digestions were 

performed using a microwave oven-process as described elsewhere (Roth and others, 1997; 

Hayes, 1993). Concentrations were determined by the appropriate analytical method in triplicate 

and reported with an error term representing the standard deviation of replicate measurements. 

Accuracy of these analyses was established using NIST SRM Buffalo River Sediment (SRM 

2704). Digestion blanks also were analyzed. Analyses are reported on a dry-weight basis. 

Detection limits for the sediment determinations are reported in table 2-14. 

32
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 2-16. Twenty-eight organochlorine compounds measured in fish tissue, semipermeable membrane 

devices, and sediment samples by USGS NWQL Schedule 2101. [CAS Number, Chemical Abstract 

Services registry number; LRL, laboratory reporting level; μg/kg, microgram per kilogram; NA, not 

available] 

Compound CAS Number 

 LRL 

(μg/kg) 

Aldrin 309-00-2 5.0 

cis-Chlordane 5103-71-9 5.0 

trans-Chlordane 5103-74-2 5.0 

1,1-Dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane (o,p'-DDD) 53-19-0 5.0 

p,p'-DDD 72-54-8 5.0 

1,1-Dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethylene (o,p'-DDE) 3424-82-6 5.0 

p,p'-DDE 72-55-9 5.0 

1,1,1-Trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane (o,p'-DDT) 789-02-6 5.0 

p,p'-DDT 50-29-3 5.0 

Dacthal 1861-32-1 5.0 

Dieldrin 60-57-1 5.0 

Endrin 72-20-8 5.0 

Endosulfan I 959-98-8 NA 

Endosulfan II 33213-65-9 NA 

alpha-Hexachlorohexane 319-84-6 5.0 

beta-Hexachlorohexane 319-85-7 5.0 

delta-Hexachlorohexane 319-86-8 5.0 

gamma-Hexachlorohexane (lindane) 58-89-9 5.0 

Heptachlor 76-44-8 5.0 

Heptachlor epoxide 1024-57-3 5.0 

Hexachlorobenzene 118-74-1 5.0 

o,p'-Methoxychlor 30667-99-3 5.0 

p,p'-Methoxychlor 72-43-5 5.0 

Mirex 2385-85-5 5.0 

cis-Nonachlor 5103-73-1 5.0 

trans-Nonachlor 39765-80-5 5.0 

Oxychlordane 27304-13-8 5.0 

Pentachloroanisole 1825-21-4 5.0 

Polychlorinated biphenyls 1336-36-3 50 

Toxaphene 8001-35-2 200 

Lipid NA 0.5% 

Surrogate Standards 

3,5-Dichlorobiphenyl 34883-41-5 0.1 

alpha-Hexachlorohexane-d6 86194-41-4 0.1 

2,2',3,3',4,4',5,6,6'-Nonachlorobiphenyl 52663-79-3 0.1 

2,4,6-Trichlorobiphenyl 35693-92-6 0.1 

33
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

34
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

CHAPTER 3 - ORGANIC COMPOUNDS IN WATER, BIOTA, 

SEMIPERMEABLE MEMBRANE DEVICES, AND SEDIMENT 

 Water samples collected from wetland sites and downstream Salt/Gila River locations 

were analyzed for a variety of parameters including field measurements (temperature, DO, pH, 

specific conductance), TOC, DOC, UV254, pesticides, herbicides, insecticides, VOC, EDTA, 

NTA, and NPEC. Biota, SPMD, and sediment were collected and analyzed for HOC. Although 

over 200 specific compounds were measured (see Chapter 2), only compounds that were 

detected are reported in this chapter. 

WATER 

FIELD MEASUREMENTS 

 Table 3-1 summarizes the field and bulk organic measurements for samples collected 

from the wetlands and the Salt/Gila River system. Two Hydrolabs were deployed for one month 

(July 24 to August 21, 1998) in the inlet and outlet of the H2 wetland, to continuously monitor 

(at one hour intervals) temperature, DO, pH, and conductivity (fig. 3-1). The Hydrolab 

temperature profiles indicated a diurnal fluctuation of nearly 5 °C at both the inlet and outlet sites 

(fig. 3-1a). The inlet temperature averaged 33 °C while the outlet averaged 31 °C. 

Figure 3-1b shows DO levels during the field survey. Although the influent DO probe 

failed several days after the experiment began, early readings indicated an average of 94% 

saturation at the wetland inlet. Both inlet and outlet results indicate a diurnal DO variation of 14 

to 47%. The outlet DO measurements remained primarily in the 0 to 20% saturation range but 

approached 40% saturation twice near the end of the study. Dissolved oxygen conditions ranged 

from aerobic to anaerobic from the inlet to the outlet location. 

The pH values averaged 7.3 (ranged from 7.1 to 7.4) at the wetland inlet and 6.7 (ranged 

from 6.5 to 7.3) at the outlet (fig. 3-1c). The pH measurements displayed a minor daily 

fluctuation that was more pronounced at the inlet. As the study concluded (August 16 to August 

21), the outlet pH levels had large daily values that occurred at 9:00 am. 

Specific conductance showed considerable variation over the 30-day study (fig. 3-1d). 

The inlet specific conductance ranged from 1.6 to 1.9 millisiemens per centimeter (mS/cm) while 

the outlet ranged from 1.5 to 1.8 mS/cm. The inlet experienced an average 0.1 mS/cm diurnal 

fluctuation whereas the outlet had only minor daily changes in specific conductance. Overall, the 

inlet and outlet specific conductance followed similar trends throughout the study. The outlet 

experienced a 0.2 mS/cm decrease near the end of the study, an anomaly that occurred several 

days before the significant pH and temperature deviations. 

35
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 3-1. Summary of specific sampling information, field measurements, and organic carbon analysis 

for 1998 to 2000 water sampling events. [Temp, water temperature in degrees Celsius, o

C; DO, dissolved 

oxygen; mg/L, milligrams per liter; SC, specific conductance; mS/cm, millisiemens per centimeter; TOC, 

total organic carbon; DOC, dissolved organic carbon; UV254, ultraviolet light absorbance at 254 

nanometers; cm, centimeter; ND, not determined] 

Date Time Location pH 

Temp o

C 

DO 

mg/L 

SC 

mS/cm 

TOC 

mg/L 

DOC 

mg/L 

TOC 

UV254 

cm 

DOC 

UV254 

cm 

7/24/98 0830 Hayfield Inlet 7.41 32.4 5.1 1.71 8.5 8.3 0.142 0.130 

7/24/98 0900 Hayfield 2 Outlet 7.13 29.8 0.6 1.67 8.4 8.6 0.156 0.160 

7/24/98 1200 Bullard Avenue 7.70 32.6 7.6 1.97 6.5 6.4 0.111 0.108 

7/28/98 ND Hayfield Inlet 7.29 33.2 2.1 1.83 8.3 8.2 0.152 0.141 

7/28/98 ND Hayfield 2 Outlet 7.19 30.8 0.5 1.67 8.3 8.3 0.190 0.191 

8/4/98 1000 Hayfield Inlet 7.24 33.4 3.8 1.71 9.1 8.9 0.160 0.137 

8/4/98 1015 Hayfield 2 Outlet 7.07 32.6 2.3 1.73 9.2 9.2 0.183 0.182 

8/10/98 ND Hayfield Inlet 7.14 31.9 4.4 1.66 7.5 7.2 0.138 0.127 

8/10/98 ND Hayfield 2 Outlet 7.23 28.8 1.2 1.75 7.6 7.7 0.158 0.155 

8/18/98 ND Hayfield Inlet 6.73 32.0 4.4 1.70 7.7 7.5 0.147 0.133 

8/18/98 ND Hayfield 2 Outlet 6.71 28.8 1.0 1.69 8.4 8.4 0.175 0.175 

6/22/99 1715 Hayfield Inlet ND 30.6 ND 1.70 7.6 5.4 0.146 0.119 

6/22/99 1730 Hayfield 1 Outlet ND 27.8 ND 1.72 7.9 8.0 0.154 0.156 

2/14/00 1345 Bullard Avenue 7.51 19.4 5.6 2.35 5.7 5.7 0.117 0.118 

2/14/00 1630 115th Avenue 7.04 22.6 3.9 2.10 6.0 6.0 0.113 0.110 

2/14/00 0830 Cobble Inlet 6.97 24.6 3.5 1.35 9.7 9.3 0.172 0.155 

2/14/00 0915 Cobble 1 Outlet 7.26 16.7 6.6 1.38 8.5 8.7 0.142 0.145 

2/14/00 0900 Cobble 2 Outlet 7.21 14.7 2.5 1.32 8.3 8.2 0.147 0.147 

2/14/00 0745 Hayfield Inlet 6.90 24.6 3.2 1.36 9.6 9.4 0.168 0.154 

2/14/00 0800 Hayfield 1 Outlet 7.31 14.6 2.8 1.39 8.3 8.4 0.153 0.151 

2/14/00 0815 Hayfield 2 Outlet 7.31 14.5 4.9 1.37 8.3 8.3 0.157 0.143 

TOTAL AND DISSOLVED ORGANIC CARBON 

 Total and dissolved organic carbon were measured at the Hayfield and Cobble wetlands 

inlets and outlets, as well as a number of other sites (table 3-1). Concentrations of TOC were 

monitored weekly at the H2 wetland during July and August 1998, and averaged 8.2 mg/L 

(ranged from 7.5 to 9.1 mg/L) in the inlet and 8.4 mg/L (ranged from 7.6 to 9.2 mg/L) in the 

outlet, an increase of about 2%. Similar results were observed for DOC which averaged 8.0 mg/L 

in the inlet and 8.4 mg/L in the outlet. Samples collected at other times during the study also 

indicated internal loading of carbon by the wetlands, which is consistent with previous studies on 

treatment wetlands (Barber and others, 1999; Sartoris and others, 2000; Rostad and others, 2000; 

Barber and others, 2001). The internal loading also is reflected by a slight increase in the specific 

absorbance (DOC/UV254) between the wetland inlets and outlets, which indicates an increase in 

aromaticity due to plant derived dissolved organic matter (Barber and others, 2001). 

PESTICIDES, HERBICIDES AND INSECTICIDES 

Pesticide analysis of the H2 wetland water samples collected during July and August 

1998 detected 7 of the 48 (15%) compounds measured (table 3-2). Diazinon, prometon, and 

simazine were detected in most samples, and atrazine, carbaryl, chloropyrifos, and S36
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

ethyldipropylthiocarbamate were identified in some samples. Additional non-target compounds 

detected in the August 21, 1998 H2 outlet sample include the ethyl ester of butenoic acid, 

ethylbenzene isomers, dimethylbenzene isomers, benzyl alcohol, 2-(methylthio)-benziathiazole, 

and phenylisoquinoline. 

Only one of the 26 (4%) herbicides measured by the Kansas laboratory was detected in 

water samples from the H2 wetland and Bullard Avenue sites during August 1998 (table 3-3). 

This compound, 3,4-dichloroaniline, is a degradate of the herbicides linuron and diuron and was 

detected in all samples. Concentrations in the wetland outlet were 57 to 127% greater than in the 

inlet indicating internal loading of the herbicide as water traveled through the wetland. Specific 

conductance measurements (table 3-1) indicate that concentration effects due to 

evapotranspiration were minor. A possible source of internal loading to the wetlands is aerial 

deposition from applications to the surrounding farmlands. Samples collected at the downstream 

Bullard Avenue site had 3,4-dichloroaniline concentrations similar to those determined in the 

wetlands. Only one of the 23 (4%) insecticides measured (chlorpyriphos) was detected in the H2 

wetland and Bullard Avenue samples (table 3-3). No herbicide metabolites were detected in 

water samples analyzed during the field study. 

7/21/1998 7/28/1998 8/4/1998 8/11/1998 8/18/1998

26

28

30

32

34

36

7/21/1998 7/28/1998 8/4/1998 8/11/1998 8/18/1998

0

20

40

60

80

100

120

7/21/1998 7/28/1998 8/4/1998 8/11/1998 8/18/1998

6.4

6.6

6.8

7.0

7.2

7.4

7.6

7/21/1998 7/28/1998 8/4/1998 8/11/1998 8/18/1998

1.4

1.5

1.6

1.7

1.8

1.9

SAMPLING DATE

a

TEMPERATURE,

in degrees Celcius

 Inlet Outlet

b

DISSOLVED OXYGEN,

in percent saturation

c

pH

Mean Inlet = 1.7 (± 0.1) mS/cm 

Mean Outlet = 1.7 (± 0.1) mS/cm Mean Inlet = 7.3 (± 0.04) 

Mean Outlet = 6.7 (± 0.1) 

Mean Inlet = 94.1% (± 9.3%) 

Mean Outlet = 9.1% (± 9.8%) 

Mean Inlet = 32.6 (± 1.2) °C

Mean Outlet = 30.8 (± 1.5) °C

d

SPECIFIC CONDUCTANCE,

in millisiemens per centimeter

Figure 3-1. Hydrolab profiles of (a) temperature, (b) dissolved oxygen, (c) pH, and (d) specific 

conductance at the Hayfield 2 wetland inlet and outlet, July 24 to August 21, 1998. 

37
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

VOLATILE ORGANIC COMPOUNDS 

The 91st Avenue WWTP effluent and the H1 wetland contained a variety of VOC 

including methylene chloride, chloroform, tetrachloroethene, 1,4-dichlorobenzene, 

bromodichloromethane, dibromochloromethane, and toluene (tables 3-4 and 3-5). Twenty-seven 

(31%) of the 86 Schedule 2020 target compounds were detected in the Hayfield inlet splitter box, 

and 18 (51%) of the 35 Schedule 2022 target compounds were detected in the H1 wetland inlet. 

Chloroform, bromodichloromethane, and dibromochloromethane were detected at the highest 

concentrations in the inlet structure, followed by a large initial decrease, and then approaching a 

plateau through the rest of the H1 wetland (fig. 3-2a). Methylene chloride, 1,4-dichlorobenzene, 

tetrachloroethene, and toluene were present at order-of-magnitude lower levels, and 

demonstrated steady decreases in concentrations during travel through the wetland (fig. 3-2b). 

Acetone, 2-butanone, bromochloromethane, carbon disulfide, chloromethane, chloroethane, 

dibromomethane, hexachloroethane, 1,4-isopropyltoluene, 4-methyl-2-pentanone, 1,2,4-

trichlorobenzene, and 1,2,3-trichloropropane were detected in the inlet splitter box; benzene, 

diethylether, tert-butyl methyl ester, and trichloroethene were present throughout the wetland; 

and bromoform, carbon tetrachloride, chlorobenzene, ethylbenzene, 1,3- 1,4-, and 1,2-xylene 

were present in the wetland inlet and the first part of the wetland. All of these compounds were 

at concentrations near their detection limits (tables 3-4 and 3-5). 

WASTEWATER-DERIVED COMPOUNDS 

 Concentrations of wastewater-derived compounds were monitored in the wetland basins 

and at several downstream locations from 1998 to 2000 (table 3-6). Twenty six (65%) of the 40 

wastewater compounds were detected in one or more sample during the study. The compounds 

most frequently detected include bisphenol A (BPA), caffeine (CAFF), cholesterol (CHO), 

coprostanol (COP), 2,6-di-tert-butyl-1,4-benzoquinone (DTBB), 1,4-dichlorobenzene (DCB), 

nonylphenol (NP), nonylphenolmonoethoxylate (NP1EO), tert-octylphenol (TOP), 

octylphenolmonoethoxylate (OP1EO), and triclosan (TRI). Figure 3-3 shows the relative 

removal of BPA, CAFF, DTBB, DCB, NP, NP1EO, and TRI in the Hayfield and Cobble 

wetlands during February 2000. The NP concentrations averaged 0.65 μg/L at the inlets and 0.39 

μg/L at the outlets, an average removal of 40%. The NP1EO concentrations averaged 0.27 μg/L 

at the inlets and 0.007 μg/L at the outlets, with an average removal of 98%. Caffeine, TRI and 

BPA had removal rates of 76%, 16%, and 44%. Concentrations also decreased in the 

downstream Salt River sites: NP, NP1EO, CAFF, and BPA levels at 115th Avenue were 9%, 

81%, 9%, and 35% lower than in the 91st Avenue WWTP effluent. In contrast, the TRI 

concentration at 115th Avenue was 60% greater than in the WWTP effluent. Concentrations at 

Bullard Avenue were significantly lower for all of the wastewater compounds, but the hydrology 

of the Salt/Gila River system becomes more complex at this site and not all of the flow comes 

from the WWTP discharge. 

38
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

ETHYLENEDIAMINETETRAACETIC, NITRILOTRIACETIC, AND 

NONYLPHENOLETHOXYCARBOXYLIC ACIDS 

 Concentrations of EDTA and NTA were monitored in the wetland basins and at several 

downstream locations from 1998 to 2000 (table 3-7). Figure 3-4a shows the relative removal of 

EDTA in the Hayfield 2 wetland between July 24 and August 21, 1998. The EDTA 

concentrations averaged 210 μg/L (ranged from 180 to 250 μg/L) at the inlet and 53 μg/L 

(ranged from 29 to 87 μg/L) at the outlet, with an average removal of 75 ± 11%. The NTA 

concentrations were much lower than EDTA and appeared to be stable through the basin 

(average concentration was 2.6 μg/L at the inlet and 3.3 μg/L at the outlet) with the exception of 

the peak value on July 28 (fig. 3-4b). 

Table 3-2. Concentrations of pesticides (USGS NWQL Schedule 2001, table 2-4) detected in water 

samples from the Hayfield 2 wetland, July 28 to August 21, 1998. [μg/L, microgram per liter; E, value 

estimated because concentration is below the laboratory reporting level] 

Compound 

Inlet 

7/28/98 

μg/L 

Inlet 

8/10/98 

μg/L 

Inlet 

8/21/98 

μg/L 

Outlet 

8/10/98 

μg/L 

Outlet 

8/21/98 

μg/L 

Atrazine <0.007 <0.007 <0.007 <0.007 E0.006 

Carbaryl <0.04 E0.005 0.035 <0.04 <0.04 

Chloropyrifos <0.005 0.011 <0.005 <0.005 <0.005 

Diazinon 0.089 0.100 0.048 0.049 0.044 

S-Ethyldipropylthiocarbamate <0.002 <0.002 0.010 <0.002 0.008 

Prometon 0.025 0.012 <0.01 0.013 0.010 

Simazine 0.011 0.013 <0.01 <0.01 0.011 

Table 3-3. Concentrations of 3,4-dichloroaniline and chlorpyriphos (USGS Lawrence, Kansas 

Laboratory, tables 2-5 and 2-6) detected in water samples collected from the Hayfield 2 wetland and the 

Gila River at Bullard Avenue, August 1998. [μg/L, microgram per liter] 

Compound 

Inlet 

8/4/98 

μg/L 

Inlet 

8/18/98 

μg/L 

Outlet 

8/4/98 

μg/L 

Outlet 

8/18/98 

μg/L 

Bullard Ave 

8/21/98 

μg/L 

Chlorpyriphos <0.05 <0.05 <0.05 <0.05 0.07 

3,4-Dichloroaniline 0.15 0.30 0.34 0.47 0.17 (0.20)a

a

. Value in parentheses is duplicate analysis. 

39
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 3-4. Volatile organic compounds (USGS NWQL Schedule 2020, table 2-8) detected in the 91st

Avenue Wastewater Treatment Plant effluent at the Hayfield wetland inlet splitter box, February 16, 

2000. [μg/L, microgram per liter; E, value estimated because concentration is below the LRL; LRL, 

laboratory reporting limit; % REC, percent recovery] 

Compound 

Inlet 

Splitter Box 

μg/L 

Blank 

μg/L 

Spike 

% REC 

LRL 

μg/L 

Acetone 9.62 <7.00 94 5.44 

Benzene E0.02 <0.04 101 0.05 

Bromochloromethane 0.31 <0.04 93 0.05 

Bromodichloromethane 5.85 <0.05 106 0.05 

Bromoform 0.33 <0.06 102 0.10 

2-Butanone 1.66 <1.60 103 1.60 

tert-Butyl methyl ether E0.09 <0.17 100 0.20 

Carbon disulfide 0.25 <0.07 90 0.07 

Carbon tetrachloride E0.05 <0.06 100 0.09 

Chlorobenzene E0.07 <0.03 104 0.05 

Chloroethane E0.06 <0.12 94 0.11 

Chloroform 8.31 <0.05 102 0.05 

Chloromethane E0.22 <0.50 126 0.16 

Dibromochloromethane 2.43 <0.18 104 0.18 

Dibromomethane 0.11 <0.05 92 0.05 

1,4-Dichlorobenzene 0.71 <0.05 93 0.05 

1,1-Dichloroethane E0.02 <0.07 100 0.07 

Diethylether E0.06 <0.17 92 0.16 

Hexachloroethane E0.02 <0.19 101 0.36 

1,4-Isopropyltoluene E0.01 <0.07 94 0.10 

Methylene chloride 0.84 <0.38 90 0.35 

4-Methyl-2-pentanone E0.19 <0.37 109 0.41 

Tetrachloroethene 0.47 <0.10 107 0.12 

Toluene 0.25 <0.05 102 0.05 

1,2,4-Trichlorobenzene E0.04 <0.19 96 0.17 

Trichloroethene E0.05 <0.04 106 0.05 

1,2,3-Trichloropropane E0.06 <0.16 88 0.19 

Surrogate Standardsa

1,4-Bromofluorobenzene 94 104 97 103 

1,2-Dichloroethane-d4 106 106 99 105 

Toluene-d8 88 102 99 103 a

. Values are percent recovery 

40
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 3-5. Volatile organic compound concentrations (USGS NWQL Schedule 2022, table 2-8) detected 

in the Hayfield 1 wetland, February 16, 2000. [DZ, deep water zone; μg/L, microgram per liter; E, value 

estimated because concentration is below LRL; LRL, laboratory reporting limit; % REC, percent 

recovery] 

Compound 

Inlet 

μg/L 

DZ-1 

μg/L 

DZ-2 

μg/L 

DZ-3 

μg/L 

DZ-4 

μg/L 

DZ-5 

μg/L 

Outlet 

μg/L 

Blank 

μg/L 

Spike 

% 

REC 

LRL 

μg/L 

Benzene E0.01 E0.01 E0.01 E0.01 E0.01 E0.01 E0.01 <0.04 101 0.05 

Bromodichloromethane 2.16 1.21 0.84 0.72 0.62 0.43 0.36 <0.05 106 0.05 

Bromoform 0.11 E0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 102 0.10 

tert-Butyl methyl ether E0.13 E0.12 E0.14 E0.13 E0.12 E0.08 E0.08 <0.17 100 0.20 

Carbon tetrachloride E0.03 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 100 0.09 

Chlorobenzene E0.03 E0.02 E0.01 E0.01 <0.03 <0.03 <0.03 <0.03 104 0.05 

Chloroform 4.45 3.25 2.79 2.55 2.25 1.73 1.50 <0.05 102 0.05 

Dibromochloromethane 0.77 0.38 0.23 0.20 0.18 E0.13 E0.10 <0.18 104 0.18 

1,4-Dichlorobenzene 0.74 0.64 0.51 0.42 0.36 0.27 0.26 <0.05 93 0.05 

Diethylether E0.10 E0.08 E0.06 E0.06 E0.06 E0.05 E0.06 <0.17 92 0.16 

Ethylbenzene E0.01 E0.01 E0.01 E0.01 <0.03 <0.03 <0.03 <0.03 103 0.05 

Methylene chloride 0.87 0.67 0.53 0.46 0.42 E0.36 E0.32 <0.38 90 0.35 

Styrene <0.04 <0.04 E0.01 <0.04 <0.04 <0.04 <0.04 <0.04 102 0.06 

Tetrachloroethene 0.48 0.38 0.31 0.26 0.22 0.18 0.17 <0.10 107 0.12 

Toluene 0.23 0.15 0.11 E0.09 E0.08 E0.07 E0.08 <0.05 102 0.05 

Trichloroethene E0.07 E0.05 E0.04 E0.04 E0.03 E0.03 E0.03 <0.04 106 0.05 

1,3- and 1,4-Xylene E0.02 E0.03 E0.03 E0.02 E0.02 E0.02 E0.02 <0.06 100 0.12 

1,2-Xylene E0.02 E0.02 E0.02 <0.04 <0.04 <0.04 E0.01 <0.04 101 0.07 

Surrogate Standardsa

1,4-Bromofluorobenzene 103 102 101 103 100 103 103 105 97 103 

1,2-Dichloroethane-d4 108 105 109 108 108 105 105 106 98 105 

Toluene-d8 99 100 98 99 98 97 99 100 99 103 a

. Values in percent recovery 

0 50 100 150 200 250

0

2

4

6

8

10

0 50 100 150 200 250

0.0

0.2

0.4

0.6

0.8

1.0

a Chloroform

 Bromodichloromethane

 Dibromochloromethane

CONCENTRATION,

in micrograms per liter

DISTANCE FROM INLET,

in meters

b

 1,4-Dichlorobenzene

 Methylene Chloride

 Tetrachloroethene

 Toluene

CONCENTRATION,

in micrograms per liter

DISTANCE FROM INLET,

in meters

Figure 3-2. Distribution of (a) chloroform, bromodichloromethane, and dibromochloromethane and (b) 

1,4-dichlorobenzene, methylene chloride, tetrachloroethene, and toluene in the Hayfield 1 wetland, 

February 16, 2000. 

41
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 3-6. Concentrations of wastewater-derived compounds at the Tres Rios Wetlands and downstream 

Saly/Gila River sites, 1998 to 2000 (USGS Boulder, Colorado Laboratory, table 2-9). [μg/L, microgram 

per liter; DUP, duplicate sample; t, tert; n, normal] Bisphenol A 4-t-Butylphenol Caffeine Cholesterol 

3-beta-Coprostanol 

2,6-Di-t-butyl-1,4-benzoquinone 2,6-Di-t-butyl-4-methylphenol 1,4-Dichlorobenzene 1,2-Dichlorobenzene 

17-alpha-Estradiol 

17-beta-Estradiol Estrone 

Sample Name Datea μg/L μg/L μg/L μg/L Μg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L

Hayfield Inlet 7/24/98 <0.01 <0.01 <0.01 0.02 <0.01 0.05 0.02 0.25 <0.01 <0.01 <0.01 <0.01

Hayfield Inlet (DUP) 7/24/98 <0.01 <0.01 <0.01 <0.01 <0.01 0.05 0.01 0.24 <0.01 0.12 <0.01 <0.01

Hayfield 2 Outlet 7/24/98 <0.01 <0.01 <0.01 <0.01 <0.01 0.02 <0.01 0.09 <0.01 0.07 <0.01 <0.01

Hayfield Inlet 7/28/98 <0.01 <0.01 <0.01 0.01 <0.01 0.05 0.02 0.20 <0.01 0.08 <0.01 <0.01

Hayfield 2 Outlet 7/28/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.06 <0.01 <0.01 <0.01 <0.01

Hayfield Inlet 8/4/98 <0.01 <0.01 <0.01 0.11 0.10 0.03 0.01 0.15 <0.01 0.64 <0.01 <0.01

Hayfield 2 Outlet 8/4/98 <0.01 <0.01 <0.01 <0.01 <0.01 0.01 <0.01 0.07 <0.01 0.08 <0.01 <0.01

Hayfield 2 Outlet 8/10/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.05 <0.01 0.28 <0.01 <0.01

Hayfield Inlet 8/18/98 <0.01 <0.01 <0.01 0.13 0.06 0.06 0.02 0.12 <0.01 0.34 <0.01 <0.01

Hayfield 2 Outlet 8/18/98 <0.01 <0.01 <0.01 <0.01 <0.01 0.02 <0.01 0.06 <0.01 0.12 <0.01 <0.01

Hayfield Inlet 8/21/98 <0.01 <0.01 <0.01 0.12 0.06 0.05 0.02 0.14 <0.01 0.13 <0.01 <0.01

Hayfield 2 Outlet 8/21/98 <0.01 <0.01 <0.01 <0.01 <0.01 0.01 <0.01 0.05 <0.01 0.12 <0.01 <0.01

Bullard Avenue 7/24/98 <0.01 <0.01 <0.01 <0.01 <0.01 0.04 <0.01 0.06 <0.01 <0.01 <0.01 <0.01

Bullard Avenue 8/21/98 <0.01 <0.01 <0.01 <0.01 <0.01 0.03 <0.01 0.03 <0.01 <0.01 <0.01 <0.01

Hayfield Inlet 2/15/00 0.12 0.03 0.49 0.04 <0.01 0.25 0.02 0.18 <0.01 <0.01 0.01 <0.01

Hayfield 1 Outlet 2/15/00 0.02 <0.01 0.08 0.11 <0.01 0.10 <0.01 0.03 <0.01 <0.01 <0.01 <0.01

Hayfield 2 Outlet 2/15/00 0.03 0.02 0.28 0.49 <0.01 0.16 <0.01 0.03 0.01 0.64 <0.01 <0.01

Cobble Inlet 2/14/00 0.12 0.02 0.65 0.57 0.36 0.47 0.04 0.17 <0.01 0.03 <0.01 <0.01

Cobble 1 Outlet 2/14/00 0.11 0.02 0.14 1.1 <0.01 0.09 0.01 0.08 <0.01 0.35 <0.01 <0.01

Cobble 2 Outlet 2/14/00 0.10 0.05 0.03 0.64 <0.01 0.12 0.02 0.07 <0.01 0.50 <0.01 <0.01

91 Avenue Well 2/16/00 <0.01 <0.01 <0.01 1.2 1.10 0.27 <0.01 <0.01 <0.01 0.04 <0.01 <0.01

115 Avenue 2/13/00 0.08 0.03 0.52 0.30 0.09 0.22 0.02 0.08 <0.01 <0.01 <0.01 <0.01

Bullard Avenue 2/13/00 <0.01 0.02 0.03 0.63 0.56 0.18 <0.01 0.03 <0.01 0.01 <0.01 0.03 a

. Samples from 1998 were isolated by solid phase extraction. 

42
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 3-6. Continued. 

4-Methylphenol 

4-Nonylphenol 4-Nonylphenolmonoethoxylate 4-Nonylphenoldiethoxylate 4-Nonylphenoltriethoxylate 4-Nonylphenoltetraethoxylate 4-n-Octylphenol 

4-t-Octylphenol 4-t-Octylphenolmonoethoxylate 4-t-Octylphenoldiethoxylate 

4-Propylphenol 

Triclosan 

Sample Name Datea μg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L

Hayfield Inlet 7/24/98 <0.01 0.37 0.47 0.36 <0.01 <0.01 <0.01 0.04 <0.01 <0.01 <0.01 0.08

Hayfield Inlet (DUP) 7/24/98 <0.01 0.35 0.28 0.25 <0.01 <0.01 <0.01 0.04 <0.01 <0.01 <0.01 0.10

Hayfield 2 Outlet 7/24/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Hayfield Inlet 7/28/98 <0.01 0.40 0.42 0.32 <0.01 <0.01 <0.01 0.05 <0.01 <0.01 <0.01 0.10

Hayfield 2 Outlet 7/28/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Hayfield Inlet 8/4/98 <0.01 0.34 0.27 0.15 <0.01 <0.01 <0.01 0.05 0.01 <0.01 <0.01 0.09

Hayfield 2 Outlet 8/4/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.02 <0.01 <0.01 <0.01 <0.01

Hayfield 2 Outlet 8/10/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Hayfield Inlet 8/18/98 <0.01 0.17 0.23 0.16 <0.01 <0.01 <0.01 0.02 <0.01 <0.01 <0.01 0.04

Hayfield 2 Outlet 8/18/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.05

Hayfield Inlet 8/21/98 <0.01 0.14 0.35 0.19 <0.01 <0.01 <0.01 0.02 <0.01 <0.01 <0.01 0.04

Hayfield 2 Outlet 8/21/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.02 <0.01 <0.01 <0.01 0.07

Bullard Avenue 7/24/98 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Bullard Avenue 8/21/98 <0.01 0.07 <0.01 0.04 <0.01 <0.01 <0.01 0.02 <0.01 <0.01 <0.01 <0.01

Hayfield Inlet 2/15/00 0.03 0.66 2.26 0.68 0.39 <0.01 <0.01 0.05 0.05 0.11 <0.01 0.08

Hayfield 1 Outlet 2/15/00 <0.01 0.22 0.07 <0.01 <0.01 <0.01 <0.01 0.02 <0.01 <0.01 <0.01 0.04

Hayfield 2 Outlet 2/15/00 <0.01 0.60 0.10 <0.01 <0.01 <0.01 0.01 0.03 <0.01 <0.01 0.03 0.13

Cobble Inlet 2/14/00 0.01 0.64 2.89 <0.01 <0.01 <0.01 0.01 0.03 0.03 0.10 0.03 0.13

Cobble 1 Outlet 2/14/00 <0.01 0.36 0.03 <0.01 <0.01 <0.01 <0.01 0.03 <0.01 <0.01 0.04 0.11

Cobble 2 Outlet 2/14/00 <0.01 0.38 <0.01 <0.01 <0.01 <0.01 0.01 0.02 <0.01 <0.01 0.04 0.07

91 Avenue Well 2/16/00 <0.01 0.04 0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

115 Avenue 2/13/00 <0.01 0.59 0.49 0.35 0.48 0.13 0.01 0.04 0.01 0.03 <0.01 0.17

Bullard Avenue 2/13/00 <0.01 0.17 0.03 0.09 <0.01 <0.01 <0.01 0.01 <0.01 <0.01 0.03 0.08

a. Samples from 1998 were isolated by solid phase extraction. 

HS In H1 Out H2 Out CS In C1 Out C2 Out 115 Ave.Bullard Ave.

0.0

0.5

1.0

1.5

2.0

2.5

CONCENTRATION,

in micrograms per liter

 bisphenol A 2,6-di-tert-butyl-benzoquinone caffeine

 1,4-dichlorobenzene 4-nonylphenol 4-NP1EO triclosan

Figure 3-3. Concentrations of select wastewater-derived compounds in the inlets and outlets of the 

Hayfield and Cobble wetlands, and the 115th Avenue and Bullard Avenue downstream Gila River sites, 

February 13 and 14, 2000.[H, Hayfield; H1, Hayfield 1 wetland; H2, Hayfield 2 wetland; C, Cobble; C1, 

Cobble 1 wetland; C2, Cobble 2 wetland; Ave, Avenue; In, Inlet; Out, outlet] 

43
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 3-7. Concentrations of ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), 

nonylphenolmonoethoxycarboxylate (NP1EC), nonylphenoldiethoxycarboxylate (NP2EC), nonylphenoltriethoxycarboxylate (NP3EC), and nonylphenoltetraethoxycarboxylate (NP4EC) at the Tres Rios 

wetlands and downstream Salt/Gila River sites, 1998 to 2000 (USGS Boulder, Colorado Laboratory, table 

2-10). [μg/L, microgram per liter; ND, not determined; % REC, percent recovery; DUP, duplicate] 

Date Site Name 

EDTA 

μg/L 

NTA 

μg/L 

NP1EC 

μg/L 

NP2EC 

μg/L 

NP3EC 

μg/L 

NP4EC 

μg/L 

4-nNP2ECa

(% REC) 

7/24/98 Hayfield Inlet 240 2.7 110 75 1.7 0.2 ND 

7/24/98 Hayfield 2 Outlet 87 3.2 57 51 1.1 0.1 ND

7/24/98 Bullard Avenue 42 6.6 81 56 0.5 <0.1 ND

7/28/98 Hayfield Inlet 250 2.5 100 82 1.5 0.1 ND

7/28/98 Hayfield 2 Outlet 53 6.8 63 60 8.6 7.9 ND

8/4/98 Hayfield Inlet 200 3.5 100 97 1.7 0.1 ND

8/4/98 Hayfield 2 Outlet 37 3.1 44 58 1.2 <0.1 ND

8/10/98 Hayfield Inlet 180 2.4 110 95 1.5 1.0 ND

8/10/98 Hayfield 2 Outlet 73 2.5 58 70 1.3 0.2 ND

8/18/98 Hayfield Inlet 210 2.0 76 66 1.4 0.3 ND

8/18/98 Hayfield 2 Outlet 29 1.9 39 47 1.0 0.2 ND

8/21/98 Hayfield Inlet 180 2.6 56 51 1.1 <0.1 ND

8/21/98 Hayfield 2 Outlet 39 2.5 38 37 0.8 <0.1 ND

8/21/98 Bullard Avenue 36 1.8 26 28 0.6 <0.1 ND

6/22/99 Hayfield Inlet 190 3.5 55 97 1.1 0.1 64 

6/22/99 Hayfield Inlet (DUP) 190 3.9 54 96 0.6 0.1 65 

6/22/99 Hayfield 1 Outlet 51 1.9 51 73 0.7 0.1 73 

6/23/99 Bullard Avenue 23 1.5 37 66 1.1 0.1 54 

2/13/00 115th Avenue 71 1.2 68 65 0.9 0.1 44 

2/13/00 Bullard Avenue 45 1.3 53 63 0.8 0.1 35 

2/14/00 Cobble Inlet 240 1.1 150 160 1.7 0.3 87 

2/14/00 Cobble 1 Outlet 76 1.4 100 130 1.2 0.2 85 

2/14/00 Cobble 2 Outlet 97 1.2 95 140 1.2 0.2 88 

2/15/00 Hayfield Inlet 310 1.6 140 150 0.9 0.1 86 

2/15/00 Hayfield 1 Outlet 41 1.2 100 120 1.0 0.2 84 

2/15/00 Hayfield 2 Outlet 46 1.1 21 79 1.4 0.2 89 

2/16/00 91st Avenue Well 9.7 0.4 1.2 3.5 0.1 <0.1 64 a

. Surrogate standard (4-normal-nonylphenoldiethoxycarboxylate). 

Figure 3-5a depicts the decreasing EDTA levels downstream of the 91st Avenue WWTP 

discharge. The 91st Avenue effluent EDTA concentrations ranged from 180 to 310 μg/L and 

concentrations in the Gila River at Bullard Avenue ranged from 23 to 45 μg/L, an average 

decrease of 84% after 12 km of travel. Figure 3-5b shows the NTA levels; the 91st Avenue 

effluent averaged 2.6 μg/L and the Gila River at Bullard Avenue averaged 2.8 μg/L. 

Between 1998 and 2000, concentrations of NP1EC ranged from 54 to 150 μg/L at the 

wetland inlets and 21 to 100 μg/L at the outlets (table 3-7). Concentrations of NP2EC ranged 

from 51 to 160 μg/L at the inlets and 37 to 140 μg/L at the outlets. On average, NP1EC and 

NP2EC concentrations decreased by 47% and 36% respectively during wetland treatment. 

Concentrations of NP3EC and NP4EC remained relatively low and stable throughout the 

wetlands with the exception of two H2 samples. 

 The H2 wetland NP1EC-NP4EC concentrations were monitored weekly between July 24 

and August 21, 1998 (table 3-7). During this time, concentrations of NP1EC in the Hayfield 

influent averaged 93 μg/L (ranged from 56 to 112 μg/L), and NP2EC concentrations averaged 78 

μg/L (ranged from 52 to 97 μg/L), and decreased 46 ± 9% and 30 ± 5% respectively at the 

44
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

wetland outlet (fig. 3-6). Although the NP3EC and NP4EC concentrations experienced a spike in 

the H2 outlet on July 28, overall, the levels were a fraction of the NP1EC and NP2EC 

concentrations and showed a slight reduction from inlet to outlet. 

 Downstream locations also were monitored for NP1EC to NP4EC (fig. 3-7). The 91st

Avenue WWTP effluent (Hayfield influent) had average concentrations of 90 and 93 μg/L of 

NP1EC and NP2EC respectively, and the Gila River at Bullard Avenue averaged 49 and 53 

μg/L, resulting in removals of 44% and 40% for NP1EC and NP2EC. Concentrations of NP3EC 

and NP4EC were very low at the downstream sites and are not shown in the figure. 

0

50

100

150

200

250

7/24/98 7/28/98 8/4/98 8/10/98 8/18/98 8/21/98

SAMPLING DATE

a

7/24/98 7/28/98 8/4/98 8/10/98 8/18/98 8/21/98

 Inlet Outlet

EDTA CONCENTRATION,

in micrograms per liter

0

2

4

6

8

b

NTA CONCENTRATION,

in micrograms per liter

Figure 3-4. Concentrations of (a) ethylenediaminetetraacetic acid, EDTA, and (b) nitrilotriacetic acid, 

NTA, in the Hayfield 2 wetland, July 24 to August 21, 1998. 

0

40

80

120

160

200

240

280

320

a

SAMPLING DATE

7/24/98 8/21/98 6/22/99 2/15/00

EDTA CONCENTRATION,

in micrograms per liter

 Hayfield Inlet Bullard Avenue

0

2

4

6

8

NTA CONCENTRATION,

in micrograms per liter

7/24/98 8/21/98 6/22/99 2/15/00

b

Figure 3-5. Concentrations of (a) ethylenediaminetetraacetic acid (EDTA), and (b) nitrilotriacetic acid 

(NTA) in the 91st Avenue Wastewater Treatment Plant effluent (Hayfield inlet) and the Gila River at 

Bullard Avenue, 1998 to 2000. 

45
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

0

20

40

60

80

100

120

a

7/24/98 7/28/98 8/4/98 8/10/98 8/18/98 8/21/98

NP1EC CONCENTRATION,

in micrograms per liter

 Inlet Outlet

0

20

40

60

80

100

120

b

7/24/98 7/28/98 8/4/98 8/10/98 8/18/98 8/21/98

NP2EC CONCENTRATION,

in micrograms per liter

0

2

4

6

8

10

SAMPLING DATE

c

7/24/98 7/28/98 8/4/98 8/10/98 8/18/98 8/21/98

NP3EC CONCENTRATION,

in micrograms per liter

0

2

4

6

8

10

d

7/24/98 7/28/98 8/4/98 8/10/98 8/18/98 8/21/98

NP4EC CONCENTRATION,

in micrograms per liter

Figure 3-6. Concentrations of (a) nonylphenolmonoethoxycarboxylate, NP1EC, (b) nonylphenoldiethoxycarboxylate, NP2EC, (c) nonylphenoltriethoxycarboxylate, NP3EC, and (d) nonylphenoltetraethoxycarboxylate, NP4EC, at the Hayfield 2 wetland inlet and outlet, July 24 to August 21, 1998. 

FISH TISSUE 

The fish specimens collected in this study exhibited no visual signs of adverse health 

effects. Whole body extracts establish tissue concentration levels and thus potential 

bioaccumulation risks to animals that feed on native fish. Study of filet tissue evaluates the 

presence of chemicals that are likely to pose a threat to humans from dietary intake. Examination 

of fish tissue evaluates persistent chemicals not metabolized by the organism. 

Gambusia and Tilapia samples were collected from the H2 wetland during July 1998 and 

analyzed for organochlorine compounds (table 3-8, fig. 3-8). The lipid content of the whole body 

Gambusia tissue was 3.3%, whereas the lipid content of the Tilapia whole-body and filet tissue 

was 2.8% and 0.9% respectively. The Tilapia whole-body tissue contained 9 μg/kg p,p’-DDD, 

26 μg/kg p,p’-DDE, and 5 μg/kg dieldrin. None of the target compounds were detected in the 

Tilapia filet tissue. The Gambusia whole-body composite sample contained 35 μg/kg of p,p’-

DDE. Overall, the fish tissue analysis showed accumulation of organochlorine pesticides during 

the 1998 sampling. 

46
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

0

20

40

60

80

100

120

140

160

SAMPLING DATE

a

7/24/98 8/21/98 6/22/99 2/15/00

NP1EC CONCENTRATION,

in micrograms per liter

 Hayfield Inlet Bullard Avenue

0

20

40

60

80

100

120

140

160

7/24/98 8/21/98 6/22/99 2/15/00

b

NP2EC CONCENTRATION,

in micrograms per liter

Figure 3-7. Concentrations of (a) nonylphenolmonoethoxycarboxylate (NP1EC), and (b) nonylphenoldiethoxycarboxylate (NP2EC) in the 91st Avenue Wastewater Treatment Plant effluent (Hayfield inlet) 

and the Gila River at Bullard Avenue, 1998 to 2000. 

Tilapia and Gambusia were collected from the Hayfield and Cobble wetlands during 

February 2000. A composite of whole-body Tilapia contained 10 μg/kg of trans-nonachlor and 

13 μg/kg of p,p’-DDE (table 3-9) whereas composite filet tissue showed no accumulation of 

target compounds above method detection limits. The liver tissue contained 9 μg/kg of transnonachlor and 13 μg/kg of p,p’-DDE (similar to the whole-body values), and the other tissue 

contained 4.5 μg/kg of trans-nonachlor and 6.5 μg/kg of p,p’-DDE (fig. 3-9). The lipid content 

of the Tilapia whole-body tissue was 1.5%, the filet was 0.9%, the liver was 3.3%, and the other 

tissue was 1.3%. Analysis of the Gambusia whole-body composite sample detected 3 μg/kg of 

cis-chlordane, 4 μg/kg of trans-chlordane, 44 μg/kg of p,p’-DDE, 8.3 μg/kg of dieldrin, 6.4 

μg/kg of lindane, and 61 μg/kg of trans-nonachlor (fig. 3-10). The greatest organochlorine 

concentration in the Gambusia whole-body tissue was 2400 μg/kg for total PCBs (table 3-9). The 

lipid content of the Gambusia whole-body tissue was 3.4%. 

Table 3-9 also reports concentrations of organochlorine pesticides detected in a June 

1996 whole-body Tilapia specimen collected at the 91st Avenue effluent channel (USGS 

National Water Quality Assessment, NAWQA, Program). The sample contained 24 μg/kg p,p’-

DDT, 17 μg/kg dieldrin, 29 μg/kg cis-nonachlor, and 14 μg/kg trans-nonachlor. The most 

significant concentrations were 1800 μg/kg for toxaphene and 2200 μg/kg for p,p’-DDE. These 

higher concentrations suggest greater exposure to HOC in the Salt River than in the treatment 

wetlands. 

The compartmentalized approach indicates bioconcentration potential for animals that 

feed on whole Tilapia residing in the wetlands. The absence of contaminants in the filet tissue 

indicates a reduced risk to humans that eat only the filet of the Tilapia. The Tilapia and 

Gambusia data both show the presence of p,p’-DDE and trans-nonachlor. Concentrations in the 

Gambusia were higher than in the Tilapia. Gambusia also accumulated several compounds not 

detected in the Tilapia specimens but that were present in the SPMD extracts. 

47
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 3-8. Concentrations (wet weight) of organochlorine pesticides (USGS NWQL Schedule 2101, table 

2-16) in Tilapia whole-body and filet tissue (collected July 23, 1998), Gambusia whole-body tissue 

(collected July 23, 1998), and sediment samples (collected August 21, 1998) from the Hayfield wetlands. 

[μg/kg, microgram per kilogram; ND, not determined; E, estimated - compound was detected at 

concentrations below the laboratory reporting level] 

Compound 

Tilapia 

Whole 

Body 

μg/kg 

Tilapia 

Filet 

μg/kg 

Gambusia 

Whole 

Body 

μg/kg 

Hayfield 2 

Inlet 

Sediment 

μg/kg 

Hayfield 2 

Outlet 

Sediment 

μg/kg 

Lipid 2.8% 0.9% 3.3% ND ND 

cis-Chlordane <5 <5 <5 <1 E<1

trans-Chlordane <5 <5 <5 1 E<1

Dacthal <5 <5 <5 <1 E<1

p,p’-DDD 9 <5 <5 E<1 E<1

p,p’-DDE 26 <5 35 E<1 E<1

Dieldrin 5.1 <5 <5 <1 E<1

Endosulfan I <5 <5 <5 <1 E<1

Hexachlorobenzene <5 <5 <5 <1 E<1

cis-Nonachlor <5 <5 <5 <1 E<1

trans-Nonachlor <5 <5 <5 <1 E<1

Surrogate Standardsa

3,5-Dichlorobiphenyl 72 98 72 ND ND 

alpha-Hexachlorohexane d6 84 85 69 102 54 

Nonachlorobiphenyl 84 85 67 ND ND a

. Surrogate standard recovery in percent. 

0

10

20

30

40

COMPOUND

p,p'-DDD p,p'-DDE Dieldrin

CONCENTRATION,

in microgram per kilogram

Tilapia Gambusia

Figure 3-8. Concentrations of organochlorine pesticides in Tilapia and Gambusia whole-body tissue 

collected in the Hayfield 2 wetland, July 23, 1998. 

48
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 3-9. Concentrations of organochlorine pesticides (USGS NWQL Schedule 2101, table 2-16) in 

Tilapia whole-body, filet, liver, and other tissue and Gambusia whole-body tissue collected February 14, 

2000 at the Hayfield and Cobble wetlands, and June 1996 at the 91st Avenue effluent channel. [μg/kg, 

microgram per kilogram; E, estimated concentration; ND, not determined] 

Compound 

Tilapia 

Whole 

Body 

μg/kg 

Tilapia 

Filet 

μg/kg 

Tilapia 

Liver 

μg/kg 

Tilapia 

Other 

μg/kg 

Gambusia 

Whole 

Body 

μg/kg 

Tilapiaa

Whole 

Body 

μg/kg 

Lipid 1.5% 0.9% 3.3% 1.3% 3.4% 4.8% 

cis-Chlordane <5 <5 <5 <5 E3 <5 

trans-Chlordane <5 <5 <5 <5 E4 <5 

p,p'-DDD <5 <5 <5 <5 <5 9 

o,p'-DDE <5 <5 <5 <5 <5 9 

p,p'-DDE 13 <5 13 6.5 44 2200 

o,p'-DDT <5 <5 <5 <5 <5 7 

p,p'-DDT <5 <5 <5 <5 <5 24 

Dieldrin <5 <5 <5 <5 8.3 17 

Lindane <5 <5 <5 <5 6.4 <5 

o,p’-Methoxychlor <5 <5 <5 <5 <5 12 

p,p’-Methoxychlor <5 <5 <5 <5 <5 7 

cis-Nonachlor <5 <5 <5 <5 <5 29 

trans-Nonachlor 10 <5 9 E4.5 61 14 

PCB <50 <50 <50 <50 2400 <50 

Toxaphene <200 <200 <200 <200 <200 1800 

Surrogate Standardsb

alpha-Hexachlorohexane d6 102 106 90 95 83 87 

Nonachlorobiphenyl 91 84 81 81 78 ND a

. Sample collected 6/5/96 at the 91st Avenue effluent channel. b

. Surrogate standard recovery in percent. 

0

15

30

45

60

COMPOUND

trans-Nonachlor p,p'-DDE

CONCENTRATION,

in micrograms per kilogram

Tilapia Whole-Body Tilapia Other

Tilapia Liver Gambusia Whole-Body

Figure 3-9. Concentrations of p,p’-DDE and trans-nonachlor in Tilapia whole-body, liver, and other 

tissue and Gambusia whole-body tissue collected in the Hayfield and Cobble wetlands, February 14, 

2000. 

49
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

0

10

20

30

40

50

60

COMPOUND

 trans- p,p'-DDE Dieldrin Lindane trans- cis-

 Nonachlor Chlordane Chlordane

CONCENTRATION,

in micrograms per kilogram

Figure 3-10. Concentrations of organochlorine pesticides in Gambusia whole-body tissue collected in the 

Cobble wetland, February 14, 2000. 

SEMIPERMEABLE MEMBRANE DEVICES 

1998 DEPLOYMENT

Results from the 28 day summer (July 24 to August 21, 1998) SPMD deployment 

indicate that concentrations of HOC declined between the inlet and outlet of the H2 wetland, and 

also decreased downstream of the 91st Avenue WWTP (table 3-10). Concentrations of HOC 

detected in the SPMD extracts were converted to μg/kg using the standard weight of 5 SPMD 

(22.495 grams). Compounds detected in the trip blank were transferred to the SPMD through 

airborne transport or handling of the devices during deployment, retrieval, and laboratory 

processing. The trip blank contained traces (<5 μg/kg) of hexachlorobenzene, trans-nonachlor, 

pentachloroanisole, and more significant concentrations of cis-chlordane, and trans-chlordane. 

Target HOC in the SPMD extracts typically decreased from inlet to outlet within the H2 

wetland (fig. 3-11). The SPMD field data indicate a 70 to 90% reduction in cis-chlordane, transchlorodane, dieldrin, p,p’-DDE, heptachlor epoxide, lindane, and trans-nonachlor, and a 90 to 

>99% reduction in dacthal, hexachlorobenzene, cis-nonachlor, oxychlordane, and 

pentachloroanisole concentrations between the wetland inlet and outlet locations. Endosulfan 

isomers exhibited more conservative behavior within the system with endosulfan I showing little 

change in concentration whereas endosulfan II decreased 96% within the wetland. In addition to 

HOC, several wastewater compounds also were detected in the SPMD, with NP and TRI having 

the highest concentrations. There was no significant reduction in wastewater compound 

concentrations between the inlet and outlet, although concentrations were only estimated. 

The SPMD recovered from the Bullard Avenue site were covered with a thick algae 

biomass that may have hindered contaminant uptake. Generally, concentrations at the Bullard 

50
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Avenue site decreased 80 to >99% relative to the H2 wetland outlet for p,p’-DDE, endosulfan I, 

endosulfan II, heptachlor epoxide, and lindane. Cis-chlordane, trans-chlordane, 

hexachlorobenzene, trans-nonachlor, and pentachloroanisole also showed significant decreases 

in SPMD concentrations, and were present at levels near those detected in the trip blank. The 

SPMD deployed at the Bullard Avenue site had nominal levels of o,p’-DDE, endrin, and cisnonachlor which were not detected in the H2 wetland effluent. 

Table 3-10. Concentrations of organochlorine pesticides (USGS NWQL Schedule 2101, table 2-16) and 

wastewater-derived compounds (table 2-9) in semipermeable membrane devices deployed in the Hayfield 

2 wetland inlet and outlet and the Gila River at Bullard Avenue, July 24 to August 21, 1998. [μg/kg, 

micrograms per kilogram; E, value estimated because concentration is below laboratory reporting level, 

above highest point on the calibration curve, or for the wastewater compounds have not been validated 

through the GPC cleanup procedure; ND, not determined] 

Compound 

Trip Blank 

μg/kg 

Inlet 

μg/kg 

Outlet 

μg/kg 

Bullard Avenue 

μg/kg 

Organochlorine Compounds 

cis-Chlordane 3.2 E32 8.8 1.2 

trans-Chlordane 3.8 E38 10 1.1 

Dacthal <1 E0.24 <5 <5 

o,p’-DDE <5 <5 <5 1.4 

p,p’-DDE <5 13 3.6 E0.30 

Dieldrin <5 E92 E26 5.2 

Endosulfan I <5 E24 E24 2.4 

Endosulfan II <5 168 E7.4 E0.90 

Endrin <5 <5 <5 1.2 

Heptachlor epoxide <5 13 3.2 E0.26 

Hexachlorobenzene E0.60 E18 1.8 E0.34 

Lindane <5 E140 38 2.2 

cis-Nonachlor <5 2.8 <5 E0.24 

trans-Nonachlor E0.98 13 3.4 E0.76 

Oxychlordane <5 4.6 <5 <5 

Pentachloroanisole E0.50 E36 2.4 E0.42 

Wastewater Compounds 

Bisphenol A <0.1 E0.1 <0.1 ND

2,6-Di-tert-butylbenzoquinone <0.1 <0.1 E0.1 ND

2,6-Di-tert-butylphenol <0.1 E0.1 <0.1 ND

1,4-Dichlorobenzene <0.1 E0.2 E0.3 ND 

Nonylphenol E0.1 E15.2 E19.8 ND

Nonylphenolmonoethoxylate <0.1 E0.1 <0.1 ND

Nonylphenoldiethoxylate <0.1 E0.4 E0.1 ND

normal-Octylphenol <0.1 E0.5 E0.6 ND

tert-Octylphenol E2.3 E0.3 E0.9 ND

Octylphenoldiethoxylate <0.1 E0.8 E3.2 ND

Triclosan <0.1 E4.6 E4.2 ND

Surrogate Standardsa

alpha-Hexachlorohexane d6 ND ND ND ND

Nonachlorobiphenyl ND ND ND ND a

. Surrogate standard recovery in percent. 

51
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

1999 DEPLOYMENT 

A SPMD time-course study was conducted in 1999 to evaluate uptake characteristics of 

HOC in the wetland basins. Duplicate canisters containing 5 individual SPMD were deployed in 

the H1 wetland inlet and outlet, and single SPMD were removed from both locations after 1, 2, 

4, 6, and 8 weeks to determine concentrations of HOC amassing in the SPMD as a function of 

time (table 3-11). Cis-chlordane, trans-chlordane, and trans-nonachlor had significant removal 

(90 ± 8%, 97 ± 3%, and 81 ± 5% respectively) between the H1 wetland inlet and outlet (fig. 3-

12). At the inlet, cis-chlordane and trans-chlordane reached steady state by the end of week 4. 

The outlet trans-nonachlor levels appeared to reach steady state by the end of week 6. 

Dieldrin had linear uptake in the first 2 weeks and reached equilibrium by the end of 

week 4 at the Hayfield 1 inlet (fig. 3-13a). The outlet SPMD had linear uptake for 4 weeks and 

reached steady state by week 6. Clearance of dieldrin was observed during weeks 6 and 8 at the 

inlet and during week 8 at the outlet. The average removal of dieldrin in the wetland was 64 ± 

12%. Pentachloroanisole achieved equilibrium with the inlet SPMD in 4 weeks and then 

experienced a rapid clearance (fig. 3-13b). Outlet concentrations were 17 to 42% larger than inlet 

levels during the first 2 weeks. At week 4, the inlet SPMD pentachloroanisole concentration was 

71% larger than the outlet concentration. Between weeks 4 and 8, the inlet pentachloroanisole 

levels decreased (46 ± 10%) from initial steady-state conditions and the outlet levels completely 

disappeared. Lindane followed a similar pattern of uptake as dieldrin and reached equilibrium 

with the inlet SPMD rapidly (fig. 3-13c), and the outlet SPMD exhibited linear uptake for the 

first 2 weeks and then leveled off. Lindane underwent an average of 37 ± 20% removal within 

the wetland. The inlet and outlet p,p’-DDE concentrations mimicked each other throughout the 8 

week period (fig. 3-13d). The outlet levels were 10 to 48% higher than inlet concentrations for 

the first 4 weeks. The apparent internal loading may have resulted from historical DDT use in the 

former agricultural field at this site. The inlet and outlet SPMD had a 35 to 41% clearance of 

p,p’-DDE in week 6, and by week 8 the concentrations had increased 50 ± 8%. These results 

show the dynamic nature of the exposure of aquatic organisms to HOC. 

SEDIMENT 

Sediment samples provide a record of compounds that have sorbed and settled out of 

solution over time. Aquatic organisms ingest colloidal and particulate bound pollutants that can 

bioaccumulate. Wetland soils indicate types of contaminants that can be resuspended by 

disturbance or desorption mechanisms. The amount of chemical sorbed to sediments is a function 

of contact time, sediment properties, and compound properties. Table 3-8 presents data for HOC 

associated with wetland soils collected from the H2 wetland inlet and outlet on August 21, 1998. 

In addition to the compounds listed in table 3-8, the inlet sediments contained trace levels of cischlordane, trans-chlordane, dacthal, dieldrin, endosulfan I, hexachlorobenzene, cis-nonachlor, 

and trans-nonachlor. The outlet soil sample had no detectable HOC. 

52
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

0

10

20

30

40

b

 trans- cis- Endosulfan I HexachloroChlordane Chlordane benzene

CONCENTRATION,

in micrograms per kilogram

0

50

100

150

Endosulfan II Lindane Dieldrin Pentachloro-

 Anisole

a

CONCENTRATION,

in micrograms per kilogram

 Inlet Outlet Bullard Ave

0

5

10

15

 cisNonachlor

COMPOUND

c

Heptachlor

Epoxide

p,p'-DDE transNonachlor

CONCENTRATION,

in micrograms per kilograms

Figure 3-11. Concentrations of (a) endosulfan II, lindane, dieldrin, and pentachloroanisole, (b) transchlordane, cis-chlordane, endosulfan I, and hexachlorobenzene, and (c) p,p’-DDE, heptachlor epoxide, 

trans-nonachlor, and cis-nonachlor in semipermeable membrane devices deployed at the Hayfield 2 

wetland inlet and outlet and the Gila River at Bullard Avenue, July 24 to August 21, 1998. 

53
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 3-11. Concentrations of organochlorine pesticides (USGS NWQL Schedule 2101, table 2-16) in 

semipermeable membrane devices collected after 1, 2, 4, 6, and 8 week deployments at the Hayfield 1 

wetland inlet and outlet, June 24 to August 19, 1999. [% REC, percent recovery; μg/kg, microgram per 

kilogram; E, estimated value] 

Compound 

Reagent 

Spike 

% REC 

Reagent 

Blank 

μg/kg 

Trip 

Blank 

μg/kg 

Inlet 

7/1/99 

μg/kg 

Outlet 

7/1/99 

μg/kg 

Inlet 

7/8/99 

μg/kg 

Outlet 

7/8/99 

μg/kg 

cis-Chlordane 109 <5.0 E1.4 E2.8 E1.7 E3.0 E1.0

trans-Chlordane 112 <5.0 E2.1 E3.9 E2.2 E3.3 E1.4

p,p'-DDE 97 <5.0 <5.0 E1.4 E2.7 E2.0 E3.4

Dieldrin 120 <5.0 <5.0 E3.6 E1.0 5.2 E1.6

Endrin 133 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0

Hexachlorobenzene 92 <5.0 <5.0 <5.0 E1.0 <5.0 E1.5

Lindane 107 <5.0 <5.0 7.1 E2.8 7.4 5.6

trans-Nonachlor 109 <5.0 E1 E26 E6.0 E42 E12

Pentachloroanisole 105 <5.0 <5.0 E4.5 7.8 10 12

Surrogate Standardsa

alpha-Hexachlorohexane d6 70 60 72 92 61 109 68

Nonachlorobiphenyl 65 65 63 67 66 66 66

Compound 

Inlet 

7/22/99 

μg/kg 

Outlet 

7/22/99 

μg/kg 

Inlet 

8/5/99 

μg/kg 

Outlet 

8/5/99 

μg/kg 

Inlet 

8/19/99 

μg/kg 

Outlet 

8/19/99 

μg/kg 

cis-Chlordane 6.0 E1.7 E4.8 E1.8 5.2 E1.7

trans-Chlordane 6.9 E1.7 6.4 E2.4 6.5 E1.7

p,p'-DDE 6.0 6.7 E4.3 E2.2 7.7 5.0

Dieldrin 13 E3.1 11 5.3 10 E4.8

Endrin <12 <5.0 <11 <5.0 <14 <5.0

Hexachlorobenzene <5.0 E 2.5 <5.0 <5.0 E2.7 <5.0

Lindane 13 5.8 10 7.2 9.8 8.2

trans-Nonachlor E120 E16 E122 E26 E130 E23

Pentachloroanisole E28 E8.1 E13 E1.7 E17 <5.0

Surrogate Standardsa

alpha-Hexachlorohexane d6 103 70 125 65 133 70

Nonachlorobiphenyl 66 68 65 59 67 63 a

. Surrogate standard recovery in percent. 

BIOACCUMULATION 

 The SPMD exposure experiments correlate with the bioavailable p,p’-DDE present in the 

aqueous phase and fish tissue (fig. 3-14a). The SPMD analysis indicates a 71% decrease in p,p’-

DDE from inlet to outlet in 1998 and a slight increase in 1999. The fish biomass analysis shows 

accumulation of p,p’-DDE in whole-body Tilapia and Gambusia collected in 1998 and 2000. 

The levels of p,p’-DDE in Gambusia were 44% higher than in Tilapia. The Tilapia filet samples 

were free of p,p’-DDE in both samplings. The levels of p,p’-DDE in the SPMD averaged 63% 

lower than those detected in Tilapia and 79% less than detected in Gambusia. 

54
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

0

1

2

3

4

5

6

7

8

7/1/99 7/8/99 7/22/99 8/5/99 8/19/99

b

trans-CHLORDANE CONCENTRATION,

in micrograms per kilogram

0

1

2

3

4

5

6

7/1/99 7/8/99 7/22/99 8/5/99 8/19/99

a

cis-CHLORDANE CONCENTRATION,

in micrograms per kilogram

 Inlet Outlet

0

50

100

150

7/1/99 7/8/99 7/22/99 8/5/99 8/19/99

SAMPLING DATE

c

trans-NONACHLOR CONCENTRATION,

in micrograms per kilogram

Figure 3-12. Concentrations of (a) cis-chlordane, (b) trans-chlordane, and (c) trans-nonachlor in 

semipermeable membrane devices deployed in the Hayfield 1 wetland inlet and outlet, June 24 to August 

19, 1999. 

55
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

0

5

10

15

7/1/99 7/8/99 7/22/99 8/5/99 8/19/99

a

DIELDRIN CONCENTRATION,

in micrograms per kilogram

 Inlet Outlet

0

5

10

15

7/1/99 7/8/99 7/22/99 8/5/99 8/19/99

SAMPLING DATE

c

LINDANE CONCENTRATION,

in micrograms per kilogram

0

10

20

30

7/1/99 7/8/99 7/22/99 8/5/99 8/19/99

b

PENTACHLOROANISOLE CONCENTRATION,

in micrograms per kilogram

0

3

6

9

7/1/99 7/8/99 7/22/99 8/5/99 8/19/99

d

p,p'-DDE CONCENTRATION,

in micrograms per kilogram

Figure 3-13. Concentrations of (a) p,p’-DDE, (b) dieldrin, (c) lindane, and (d) pentachloroanisole in 

semipermeable membrane devices deployed in the Hayfield 1 wetland inlet and outlet, June 24 to August 

19, 1999. 

 The SPMD analysis also showed accumulation of trans-nonachlor, which averaged 75% 

removal between inlet and outlet sites in 1998. Concentrations in 1999 were much higher but 

showed a similar removal (fig. 3-14b). The 2000 Tilapia samples indicated nominal 

accumulations of trans-nonachlor in whole-body and liver extracts, with the other tissue extract 

having half as much trans-nonachlor. The 2000 Gambusia whole-body tissue had concentrations 

of trans-nonachlor six-times higher than the whole-body Tilapia. The 1998 sampling did not 

detect trans-nonachlor in fish tissue. 

 Dieldrin was detected in one Tilapia and one Gambusia sample as well as in both SPMD 

deployments (fig. 3-15a). There was a 76% decrease in dieldrin concentrations across the 

wetlands in SPMD deployed for 4 weeks during 1999. The inlet SPMD concentration was 36% 

higher than the Gambusia concentration. The dieldrin concentration in Tilapia was 25% lower 

than in Gambusia. 

 Lindane was accumulated during both SPMD experiments and was detected in one 

Gambusia sample (fig. 3-15b). The 1998 SPMD deployment showed a 73% decrease in lindane 

56
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

concentrations across the H2 wetland, and concentrations decreased by 53% in the H1 wetland 

during 1999. The concentration of lindane in Gambusia was equivalent to the H1 wetland outlet 

SPMD levels. Lindane was not detected in the Tilapia samples. 

 The cis-chlordane and trans-chlordane isomers significantly accumulated in the SPMD 

during the 1998 deployment, with an average 82% decrease between inlet and outlet (fig. 3-15c). 

The 1999 SPMD experiment had much lower levels of both isomers in the inlet samplers, with a 

>90% removal across the Hayfield 1 wetland. The 2000 Gambusia sample had 4 μg/kg transchlordane and 3 μg/kg cis-chlordane, roughly equal to the 1999 inlet SPMD concentrations. The 

Tilapia tissue did not have detectable chlordane concentrations. 

0

10

20

30

40

50

1999

1998

1998

1998

1998

2000

2000

2000

1999

2000

1998

a

Tilapia Gambusia H2 SPMD H1 SPMD

p,p'-DDE CONCENTRATION,

in micrograms per kilogram

Tilapia Whole-Body

Tilapia Liver

Tilapia Other

Gambusia Whole-Body

 SPMD Inlet

 SPMD Outlet

 SPMD Bullard Ave

0

15

30

45

60

75

90

105

120

135

1999

2000

1998

2000

1999

1998

2000

2000

b

Tilapia Gambusia H2 SPMD H1 SPMD

Tilapia Whole-Body

Tilapia Liver

Tilapia Other

Gambusia Whole-Body

 SPMD Inlet

 SPMD Outlet

trans-NONACHLOR CONCENTRATION,

in micrograms per kilogram

Figure 3-14. Concentrations of (a) p,p’-DDE, and (b) trans-nonachlor in Tilapia whole-body, liver, and 

other tissue and Gambusia whole-body tissue (collected from the Hayfield and Cobble wetlands, July 23, 

1998 and February 14, 2000), and inlet and outlet semipermeable membrane devices (SPMD) deployed in 

the Hayfield wetlands (Hayfield 2 wetlans, H2, deployed July 24 to August 21, 1998; Hayfield 1 wetland, 

H1, deployed June 24 to July 22, 1999). 

57
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

0

20

40

60

80

100

1999

1998

1998

1998

A

Tilapia Gambusia H2 SPMD H1 SPMD 

DIELDRIN CONCENTRATION,

in micrograms per kilogram

Tilapia Whole-Body

Gambusia Whole-Body

 SPMD Inlet

 SPMD Outlet

 SPMD Bullard Avenue

0

40

80

120

160

b

1998

1998

1998

2000

1999

1999

1999

2000

1998

Gambusia H2 SPMD H1 SPMD

LINDANE CONCENTRATION,

in micrograms per kilogram

Gambusia Whole-Body

 SPMD Inlet

 SPMD Outlet

 SPMD Bullard Ave

0

10

20

30

40

1998 2000

2000

1999

1999

1999

1999

1998

1998

1998

1998

1998

c

CHLORDANE CONCENTRATION,

in micrograms per kilogram

cis-Chlordane trans-Chlordane

Gambusia Whole-Body

 SPMD Inlet

 SPMD Outlet

 SPMD Bullard Avenue

Figure 3-15. Concentrations of (a) cis-chlordane and trans-chlordane, (b) dieldrin, and (c) lindane in 

Tilapia whole-body tissue and Gambusia whole-body tissue (collected from the Hayfield and Cobble 

wetlands, July 23, 1998 and February 14, 2000), and inlet and outlet semipermeable membrane devices 

deployed in the Hayfield wetlands (Hayfield 2 wetland, H2, deployed July 24 to August 21, 1998; 

Hayfield 1 wetland, H1, deployed June 24 to July 22, 1999). 

58
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

CHAPTER 4 - INORGANIC CONSTITUENTS IN WATER, BIOTA, 

AND SEDIMENT 

In addition to the field measurements and organic compounds reported in Chapter 3, 

inorganic compounds including major cations and anions, trace elements, and nutrients were 

measured. Results for these analyses are reported in this Chapter. 

QUALITY ASSURANCE 

ACCURACY

The level of accuracy for the determinations of major cations and trace element 

concentrations performed in this study was evaluated by three specific techniques: (1) 

measurement of natural matrix standard reference materials, (2) determination of spike recovery 

information for selected elements, and (3) measurement of laboratory blanks. This approach 

provides information regarding the proximity of reported analytical results to the best-known 

values of various elements in the measured samples. This information was used during data 

interpretation to evaluate bias or systematic error in the concentrations of major cations and trace 

elements in samples collected during the study. 

STANDARD REFERENCE MATERIALS

 

Two types of SRM were used: (1) natural matrix certified SRM produced by NIST, and 

(2) natural matrix non-certified Standard Reference Water Samples (SRWS) produced by the 

USGS. Multiple SRM were analyzed with all batches of water samples at a frequency of about 

30% of the total number of samples. The NIST standards for dissolved samples used in this study 

included: SRM 1643a Trace Elements in Water, SRM 1643b Trace Elements in Water, SRM 

1643d Trace Elements in Water. The USGS SRWS used in this study included: T-99, T-101, T103, T-105, T-107, T-111, T-113, T-117, T-119, T-125, T-129, T-131, T-133, T-135, T-137, T143 and T-145 for trace elements, and Hg-7, Hg-10, Hg-12, Hg-15 and Hg-24 for Hg 

determinations. Certified and “most probable values” for selected elements in each of these 

standards are tabulated elsewhere (Peart, 1998). Results of repeated analysis of selected elements 

are shown in figure 4-1. Standards used in this study for nutrient determinations include USGS 

SRWS N-69 and N-70. Standards used for anion measurements include USGS SRWS M-102, 

M-104 and M-134. 

SPIKE RECOVERIES

Selected samples were spiked, immediately after processing, for the following elements: 

As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, U, and Zn. Nominal concentrations for spiked elements are 

listed in table 4-1 along with the number of spiked samples and the frequency distribution of 

recovery (percent of observations within a range of percent recoveries). Specific quantities of the 

spike added varied, depending on the final volume of sample processed. Recovery was 

59
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

calculated by dividing the measured concentration of the spike by the expected value, then 

multiplying by 100 to convert to percent. 

BLANKS

Blanks for each step of sampling and processing, laboratory reagent blanks, and 

deionized water blanks were analyzed (10% frequency) with all samples. Only reagent blanks 

were used to correct analyte determinations. Process blanks were used to monitor potential 

contamination during sample collection and handling. 

1 10 100 1

10

100

1 10 100 1,000 1

10

100

1,000

10 100 1,000 10,000

10

100

1,000

10,000

1 10 100 1,000 1

10

100

1,000

REPORTED MOST PROBABLE VALUE,

in micrograms per liter

REPORTED MOST PROBABLE VALUE,

in milligrams per liter

REPORTED MOST PROBABLE VALUE,

in micrograms per liter

REPORTED MOST PROBABLE VALUE,

in micrograms per liter

c d

b a

99% Prediction Intervals

 Element

 As

 Be

 Cr

 Sb

OBSERVED CONCENTRATION, 

 V

in micrograms per liter

99% Prediction intervals

 Element

 Ca

 Mg

 Na

 SiO2

OBSERVED CONCENTRATION, 

in milligrams per liter

99% Prediction Intervals

 Element

 Al

 B

 Ba

 Fe

 Sr

 Zn

OBSERVED CONCENTRATION,

in micrograms per liter

99% Prediction Intervals

 Element

 Cu

 Li

 Mn

 Mo

OBSERVED CONCENTRATION,

 Ni

in micrograms per liter

Figure 4-1. Correlation plots of observed concentrations of (a) antimony, arsenic, beryllium, chromium 

and vanadium, (b) calcium, magnesium, sodium and silica, (c) aluminum, boron, barium, iron, strontium 

and zinc, and (d) copper, lithium, manganese, molybdenum and nickel as a function of the Standard 

Reference Water Sample Program most probable value. Solid lines represent the probable error at the 

99% confidence interval. 

60
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

PRECISION

All samples for dissolved constituents were determined in triplicate. Table 4-2 summarizes the 

relative standard deviation (RSD) of select elements. As concentrations approach the detection limit for 

specific elements, the precision of determination decreases. Figure 4-2 shows how the RSD increases as 

concentrations decrease for a typical element (Cd). The RSD is calculated by dividing the standard 

deviation by the mean, and multiplying by 100. The vertical lines represent the detection limit and ten 

times the detection limit. It is clear that RSD increases exponentially with decreasing concentration. 

Table 4-1. Percentage of determinations for selected elements that fall within the specified range of 

recovery for the certified or most probable value of the spike addition in water samples. [RECSpike , 

percent recovery with respect to spiked samples; N, number of observations; Conc., spiked concentration; 

%, percent; μg/L, micrograms per liter] 

RECSpike Percentage of spiked samples within the specified RECSpike range 

Range (%) As Cd Co Cr Cu Hg Ni Pb Se U Zn 

0 – 200 100 100 100 100 100 100 100 100 100 100 100

50 – 150 100 100 100 100 100 100 100 98 100 100 98 

75 – 125 98 100 100 98 98 100 100 98 100 98 98 

85 – 115 92 94 100 98 98 89 100 96 98 80 91 

90 – 110 78 88 98 88 85 69 96 82 94 62 83 

95 – 105 58 69 69 52 60 44 70 56 70 42 55 

N 50 48 49 50 47 36 50 50 50 50 47 

Conc. (μg/L) 10 1 5 50 10 0.004 10 50 20 10 10 

1E-3 0.01 0.1 1 10

0

50

100

150

200

0.001

10X Detection limit

Detection limit

PERCENT RELATIVE STANDARD DEVIATION

CONCENTRATION,

in micrograms per liter

Figure 4-2. Plot of precision for the determination of cadmium as a function of concentration. 

61
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 4-2. Percentage of replicate samples whose relative standard deviations fall below the specified 

values. [MDL, method detection limit; μg/L, microgram per liter; %<, percent less than; RSD, percent 

relative standard deviation; N, number of samples] 

MDL 

%< 

MDL 

%< 

100% 

%< 

50% 

%< 

25% 

%< 

15% 

%< 

10% 

%< 

5% 

Element μg/L N RSD RSD RSD RSD RSD RSD 

Al 0.05 46 0 100 100 100 98 89 76

As 0.04 46 0 100 100 98 93 89 72

B 4 46 4 100 100 98 98 91 76

Ba 0.01 46 0 100 100 100 100 98 89

Be 0.02 46 93 100 100 100 96 93 93

Bi 0.01 46 100 100 100 100 100 100 100

Ca 20 46 0 100 100 100 100 98 93

Cd 0.006 46 41 100 98 93 89 80 70

Ce 0.001 46 2 100 98 85 67 54 37

Co 0.01 46 52 100 100 96 91 89 83

Cr 0.2 46 26 100 100 93 80 65 43

Cs 0.06 46 67 96 93 91 85 76 67

Cu 0.02 46 0 100 98 98 98 96 74

Dy 0.002 46 59 100 100 91 89 85 72

Er 0.002 46 59 100 98 96 87 85 70

Eu 0.001 46 72 98 96 89 85 80 76

Fe 0.7 46 11 100 74 57 41 35 33

Gd 0.003 46 43 100 100 91 74 65 61

Hg 0.0004 47 19 100 100 74 60 55 36

Ho 0.0005 46 52 102 100 91 85 78 70

K 10 46 0 100 100 98 98 96 93

La 0.0005 46 0 100 98 93 70 61 35

Li 0.1 46 4 100 100 100 100 100 80

Lu 0.0005 46 74 100 96 91 85 83 80

Mg 15 46 0 100 100 100 100 98 91

Mn 0.02 46 0 100 100 98 98 96 89

Mo 0.03 46 7 100 100 98 85 72 50

Na 70 46 0 100 100 100 96 93 74

Nd 0.003 46 26 100 96 87 74 61 48

Ni 0.02 46 0 100 100 98 93 87 70

Pb 0.006 46 57 98 89 74 70 67 65

Pr 0.0005 46 17 100 100 87 74 65 52

Rb 0.002 46 0 100 100 100 98 98 80

Re 0.0013 46 83 100 100 93 91 91 87

Sb 0.02 46 9 100 100 91 80 72 46

Se 0.2 46 80 100 100 98 98 96 89

SiO2 50 46 0 100 100 100 100 98 93

Sm 0.003 46 74 100 100 96 93 89 85

Sr 0.02 46 0 100 100 100 98 98 96

Tb 0.0007 46 63 100 98 89 78 74 72

Tl 0.005 46 85 100 100 100 98 98 96

Tm 0.0005 46 74 100 98 91 89 85 80

U 0.002 46 7 100 100 98 96 87 70

V 0.05 46 4 100 100 100 100 98 93

Y 0.0004 46 0 100 100 93 85 74 46

Yb 0.0014 46 48 100 96 87 74 67 63

Zn 0.08 46 0 98 98 91 67 59 33

Zr 0.01 46 67 100 100 91 83 80 78

62
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

WATER 

MAJOR CATIONS AND ANIONS

 Major cations were measured in water samples collected from the inlet and outlet of the 

Hayfield 2 wetland on 5 separate days during July and August 1998 (table 4-3). These data 

demonstrate that although there was a slight increase in outlet concentrations, within 

experimental error, there was little difference in the bulk water chemistry between the inlet and 

outlet on a particular day or over the one-month period for which samples were collected (fig. 4-

3). These results are consistent with specific conductance and TOC measurements. 

Major anion and cation results for water samples collected in 1999 and 2000 from the 

Hayfield inlet and Hayfield 1 and 2 outlets, the Cobble inlet and Cobble 1 and 2 outlet, the Gila 

River at Bullard Avenue, the Gila River at 115th Avenue, and the 91st Avenue dewatering well 

sites are presented in table 4-4. As was observed for the 1998 data, there was little difference in 

the bulk water chemistry between the inlets and outlets of the Hayfield and Cobble wetlands. 

Results for replicate samples, collected for quality control purposes, also are included in table 4-

4 and show excellent agreement. For the Cobble wetlands inlet and outlet samples collected in 

June 1999 and February 2000, no differences are observed for any of the major ions. Comparable 

samples collected from the Hayfield site in February 2000 indicated a minor elevation in 

concentration of major constituents in the outlets relative to the inlet. 

Table 4-3. Summary of major cation results for water samples collected from the Hayfield wetland inlet 

and Hayfield 2 wetland outlet, July to August 1998. 

Element 

Concentration 

Unit 

Hayfield 

Inlet 

7/24/98 

Hayfield 2 

Outlet 

7/24/98 

Hayfield 

Inlet 

7/28/98 

Hayfield 2 

Outlet 

7/28/98 

Hayfield 

Inlet 

8/4/98 

Ca mg/L 59 ± 1 61 ± 2 62 ± 2 62 ± 0 61 ± 2 

Mg mg/L 23 ± 0 25 ± 1 25 ± 1 25 ± 0 25 ± 0 

Na mg/L 215 ± 0 227 ± 2 232 ± 9 232 ± 2 229 ± 0 

K mg/L 18 ± 1 20 ± 1 19 ± 1 21 ± 1 20 ± 0 

SiO2 mg/L 19 ± 0 19 ± 0 20 ± 0 20 ± 0 20 ± 0 

Element 

Concentration 

Unit 

Hayfield 2 

Outlet 

8/4/98 

Hayfield 

Inlet 

8/10/98 

Hayfield 2 

Outlet 

8/10/98 

Hayfield 

Inlet 

8/18/98 

Hayfield 2 

Outlet 

8/18/98 

Ca mg/L 62 ± 2 58 ± 3 63 ± 0 61 ± 3 62 ± 2 

Mg mg/L 26 ± 0 24 ± 0 25 ± 0 25 ± 0 25 ± 0 

Na mg/L 233 ± 1 227 ± 2 239 ± 1 234 ± 0 232 ± 0 

K mg/L 22 ± 0 19 ± 0 21 ± 0 20 ± 0 21 ± 0 

SiO2 mg/L 20 ± 1 18 ± 0 20 ± 2 20 ± 0 19 ± 1 

63
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

7/24/1998 7/28/1998 8/4/1998 8/10/1998 8/18/1998

0

10

20

30

40

50

60

a

CALCIUM CONCENTRATION,

in milligrams per liter

SAMPLING DATE

 Inlet Outlet

7/24/1998 7/28/1998 8/4/1998 8/10/1998 8/18/1998

0

50

100

150

200

250

b

SODIUM CONCENTRATION,

in milligrams per liter

SAMPLING DATE

 Inlet Outlet

Figure 4-3. Plots of dissolved (a) calcium and (b) sodium concentrations in water samples collected from 

the Hayfield 2 wetland inlet and outlet on various days from July 24 to August 18, 1998. 

TRACE ELEMENTS

 Trace elements listed in table 2-11 were determined in water samples collected from the 

inlet and outlet of the H2 wetland during July and August 1998 (table 4-5). The results are fairly 

consistent from day to day for both inlet and outlet samples. Several trace elements had average 

concentrations in the inlet that were higher (>20%) that in the outlet (Al, Bi, Cd, Cr, Cs, Cu, Gd, 

Ni, Pb, Sb, Se, Tl, U, V, Zn), some had similar concentrations (<20% difference) in the inlet and 

outlet (As, B, Co, Fe, Li, Mo, Rb, Re, Sr, Te, and Zr), and others had greater (>20%) 

concentrations in the outlet than the inlet (Ba, Be, Ce, Dy, Er, Eu, Ho, La, Lu, Mn, Nd, Pr, Sm, 

Tb, Th, Tm, Y, Yb). Example plots of As, Cu, Pb and Zn are shown in figure 4-4. These results 

show that As concentrations increase slightly in the wetlands (average outlet concentration was 

9.2% higher than the inlet), whereas the Cu, Pb, and Zn concentrations were significantly 

reduced (92%, 56% and 60% respectively). 

Trace element analyses for water samples collected in 1999 and 2000 from the Hayfield 

wetland inlet and H1 and H2 outlets, the Cobble wetland inlet and C1 and C2 outlets, the Gila 

River at Bullard Avenue, the Gila River at 115th Avenue, and the 91st Avenue dewatering well 

sites are presented in table 4-6. Comparison of results for selected trace elements (Al, As, Cd, 

Cu, Pb, and Zn) at each of the sites sampled during February 2000 are shown in figure 4-5. 

64
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 4-4. Summary of duplicate major anion and cation results for water samples collected from the 

Cobble wetland inlet, Cobble 2 wetland outlet, and the Gila River at Bullard Avenue during June 1999, 

and from the Cobble wetland inlet, Cobble 1 and Cobble 2 wetlands outlets, Hayfield wetland inlet, 

Hayfield 1 and Hayfield 2 wetlands outlets, the Gila River at 115th and Bullard Avenues, and the 91st

Avenue dewatering well during February 2000. 

Element 

Concentration 

Unit 

Cobble 

Inlet 

6/23/99 

Cobble 

Inlet 

6/23/99 

Cobble 2 

Outlet 

6/23/99 

Cobble 2 

Outlet 

6/23/99 

Bullard 

Avenue 

6/23/99 

Bullard 

Avenue 

6/23/99 

Ca mg/L 67 ± 23 66 ± 3 63 ± 5 69 ± 5 110 ± 10 110 ± 10 

Mg mg/L 28 ± 9 28 ± 0 26 ± 2 29 ± 2 47 ± 6 48 ± 7 

Na mg/L 290 ± 10 270 ± 0 280 ± 0 290 ± 10 390 ± 20 400 ± 0 

K mg/L 24 ± 1 22 ± 1 21 ± 0 20 ± 3 20 ± 1 21 ± 0 

SiO2 mg/L 18 ± 5 19 ± 1 16 ± 1 17 ± 1 20 ± 2 20 ± 2 

Cl mg/L 420 ± 50 550 ± 40 530 ± 10 410 ± 0 730 ± 20 690 ± 50 

SO4 mg/L 194 ± 60 192 ± 7 185 ± 12 193 ± 4 275 ± 31 276 ± 34 

Element 

Concentration 

Unit 

Cobble 

Inlet 

2/14/00 

Cobble 

Inlet 

2/14/00 

Cobble 1 

Outlet 

2/14/00 

Cobble 1 

Outlet 

2/14/00 

Cobble 2 

Outlet 

2/14/00 

Cobble 2 

Outlet 

2/14/00 

Ca mg/L 60 ± 3 61 ± 1 65 ± 2 64 ± 2 64 ± 2 66 ± 2 

Mg mg/L 30 ± 1 30 ± 1 31 ± 1 31 ± 1 30 ± 1 31 ± 0 

Na mg/L 169 ± 1 165 ± 2 173 ± 3 172 ± 2 167 ± 4 169 ± 1 

K mg/L 17 ± 0 17 ± 0 18 ± 0 18 ± 0 17 ± 0 18 ± 1 

SiO2 mg/L 19 ± 1 19 ± 0 18 ± 0 17 ± 0 18 ± 0 18 ± 1 

Cl mg/L 300 ± 20 280 ± 30 300 ± 10 330 ± 10 270 ± 30 310 ± 10 

SO4 mg/L 190 ± 5 191 ± 4 210 ± 6 202 ± 5 199 ± 6 204 ± 5 

Element 

Concentration 

Unit 

Hayfield 

Inlet 

2/15/00 

Hayfield 

Inlet 

2/15/00 

Hayfield 1 

Outlet 

2/15/00 

Hayfield 1 

Outlet 

2/15/00 

Hayfield 2 

Outlet 

2/15/00 

Hayfield 2 

Outlet 

2/15/00 

Ca mg/L 65 ± 12 61 ± 21 64 ± 5 69 ± 1 70 ± 4 69 ± 4 

Mg mg/L 31 ± 6 29 ± 9 30 ± 2 32 ± 1 33 ± 3 33 ± 2 

Na mg/L 190 ± 10 190 ± 10 190 ± 20 210 ± 10 180 ± 10 190 ± 10 

K mg/L 19 ± 1 19 ± 1 19 ± 2 22 ± 1 19 ± 1 19 ± 1 

SiO2 mg/L 20 ± 3 19 ± 5 16 ± 0 17 ± 1 15 ± 1 15 ± 1 

Cl mg/L 180 ± 30 170 ± 0 170 ± 10 170 ± 10 180 ± 30 180 ± 30 

SO4 mg/L 189 ± 32 176 ± 56 185 ± 11 199 ± 56 204 ± 12 202 ± 10 

Element 

Concentration 

Unit 

Bullard 

Avenue 

2/13/00 

Bullard 

Avenue 

2/13/00 

115th

Avenue 

2/13/00 

115th

Avenue 

2/13/00 

91st Avenue 

Well 

2/16/00 

Ca mg/L 94 ± 2 93 ± 4 115 ± 2 118 ± 2 57 ± 0 

Mg mg/L 46 ± 1 46 ± 2 52 ± 2 54 ± 1 27 ± 1 

Na mg/L 270 ± 7 276 ± 4 364 ± 2 380 ± 6 290 ± 80 

K mg/L 14 ± 0 14 ± 0 15 ± 0 15 ± 0 5.9 ± 2 

SiO2 mg/L 21 ± 0 21 ± 1 20 ± 0 21 ± 0 32 ± 0 

Cl mg/L 660 ± 20 550 ± 0 910 ± 30 910 ± 40 250 ± 20 

SO4 mg/L 245 ± 2 249 ± 2 300 ± 4 310 ± 1 182 ± 2 

65
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

7/24/1998 7/28/1998 8/4/1998 8/10/1998 8/18/1998

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5 a

ARSENIC CONCENTRATION,

in micrograms per liter

SAMPLING DATE

 Inlet Outlet

7/24/1998 7/28/1998 8/4/1998 8/10/1998 8/18/1998

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

b

COPPER CONCENTRATION,

in micrograms per liter

SAMPLING DATE

 Inlet Outlet

Detection 

Limit

7/24/1998 7/28/1998 8/4/1998 8/10/1998 8/18/1998

0.00

0.05

0.10

0.15

0.20 c

LEAD CONCENTRATION,

in micrograms per liter

SAMPLING DATE

 Inlet Outlet

7/24/1998 7/28/1998 8/4/1998 8/10/1998 8/18/1998

0

5

10

15

20

25 d

ZINC CONCENTRATION,

in micrograms per liter

SAMPLING DATE

 Inlet Outlet

Figure 4-4. Plots of dissolved (a) arsenic, (b) copper, (c) lead, and (d) zinc concentrations in water 

samples collected from the Hayfield 2 wetland inlet and outlet on various days from July 24 to August 18, 

1998. 

66
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 4-5. Concentrations of dissolved trace elements for water samples collected from the Hayfield 

wetland inlet and the Hayfield 2 wetland outlet during July to August 1998. [μg/L, micrograms per liter] 

Concen- Hayfield Hayfield 2 

tration Inlet Outlet 

Element Unit 7/24/98 7/24/98 

Hayfield 

Inlet 

7/28/98 

Hayfield 2 

Outlet 

7/28/98 

Hayfield 

Inlet 

8/4/98 

Al μg/L 9.9 ± 1 1.8 ± 0.2 11 ± 1 1.9 ± 0.3 7.9 ± 0.4

As μg/L 3.7 ± 0 3.6 ± 0 3.6 ± 0.3 3.6 ± 0 3.6 ± 0

B μg/L 364 ± 13 354 ± 1 413 ± 2 391 ± 7 385 ± 1

Ba μg/L 23 ± 0 29 ± 1 22 ± 0 31 ± 0 19 ± 0

Be μg/L < 0.008 ± 0.005 0.01 ± 0.004 < 0.008 ± 0.009 < 0.008 ± 0.003 < 0.008 ± 0.003

Bi μg/L 0.009 ± 0.003 0.002 ± 0 0.005 ± 0 0.003 ± 0.001 0.006 ± 0.002

Cd μg/L 0.23 ± 0 0.027 ± 0.003 < 0.002 ± 0.007 < 0.002 ± 0.006 < 0.002 ± 0.006

Ce μg/L 0.018 ± 0 0.033 ± 0 0.02 ± 0 0.037 ± 0 0.014 ± 0

Co μg/L 0.36 ± 0.03 0.48 ± 0.05 0.31 ± 0.01 0.28 ± 0 0.28 ± 0

Cr μg/L 0.7 ± 0.1 0.5 ± 0.1 0.8 ± 0.3 0.5 ± 0.2 0.7 ± 0.2

Cs μg/L 0.108 ± 0 0.065 ± 0 0.097 ± 0.002 0.068 ± 0.003 0.091 ± 0.003

Cu μg/L 0.71 ± 0.04 0.07 ± 0.01 0.93 ± 0.05 < 0.06 ± 0.06 1.3 ± 0.2

Dy μg/L 0.0028 ± 0.0004 0.0052 ± 0.001 0.0026 ± 0 0.006 ± 0.0001 0.0018 ± 0.0003

Er μg/L 0.002 ± 0.0005 0.0045 ± 0.0002 0.0021 ± 0.0007 0.0045 ± 0.0006 0.0019 ± 0.0005

Eu μg/L 0.0017 ± 0.0006 0.0025 ± 0.0006 0.0016 ± 0.0005 0.0029 ± 0.0011 0.0015 ± 0.0012

Fe μg/L 84 ± 0 83 ± 3 99 ± 4 168 ± 0 81 ± 0

Gd μg/L 0.081 ± 0.001 0.067 ± 0.001 0.067 ± 0.004 0.031 ± 0 0.064 ± 0.002

Ho μg/L 0.0012 ± 0.0001 0.0019 ± 0.0001 0.0012 ± 0.0001 0.0015 ± 0.0001 0.0011 ± 0

La μg/L 0.0062 ± 0.0001 0.007 ± 0.0006 0.006 ± 0.0007 0.0086 ± 0.0001 0.0054 ± 0.0002

Li μg/L 105 ± 0 105 ± 1 111 ± 1 107 ± 2 105 ± 0

Lu μg/L 0.0004 ± 0.0002 0.0008 ± 0.0001 0.0006 ± 0.0001 0.0006 ± 0.0001 0.0004 ± 0.0001

Mn μg/L 34 ± 1 76 ± 6 38 ± 0 87 ± 1 33 ± 0

Mo μg/L 25 ± 1 21 ± 0 30 ± 1 19 ± 1 26 ± 0

Nd μg/L 0.007 ± 0.002 0.014 ± 0 0.008 ± 0 0.016 ± 0.001 0.007 ± 0.001

Ni μg/L 4.6 ± 0.2 3.4 ± 0.1 4 ± 0.1 2.2 ± 0.2 8.3 ± 0.3

Pb μg/L 0.2 ± 0.01 0.06 ± 0 0.12 ± 0.01 0.04 ± 0.01 0.12 ± 0.02

Pr μg/L 0.0017 ± 0 0.0028 ± 0.0001 0.0019 ± 0.0001 0.0039 ± 0 0.0014 ± 0

Rb μg/L 15 ± 0 14 ± 0 15 ± 1 15 ± 1 15 ± 0

Re μg/L 0.081 ± 0 0.081 ± 0.002 0.085 ± 0.001 0.085 ± 0.004 0.083 ± 0.002

Sb μg/L 0.69 ± 0.01 0.43 ± 0 0.66 ± 0 0.42 ± 0 0.78 ± 0

Se μg/L 0.3 ± 0.15 < 0.09 ± 0.01 0.11 ± 0.06 < 0.09 ± 0.1 0.11 ± 0.06

Sm μg/L 0.002 ± 0 0.004 ± 0.001 0.002 ± 0 0.005 ± 0 0.002 ± 0.001

Sr μg/L 662 ± 18 692 ± 21 686 ± 24 730 ± 39 680 ± 11

Tb μg/L 0.0007 ± 0 0.001 ± 0.0002 0.0007 ± 0 0.0009 ± 0.0001 0.0006 ± 0

Te μg/L 0.031 ± 0.006 0.026 ± 0 0.036 ± 0.005 0.038 ± 0.005 0.036 ± 0.003

Th μg/L 0.0006 ± 0.0002 0.0008 ± 0.0001 0.0005 ± 0.0001 0.0006 ± 0 0.0003 ± 0.0001

Tl μg/L 0.002 ± 0 0.002 ± 0.002 0.002 ± 0.001 < 0.001 ± 0 0.002 ± 0.001

Tm μg/L 0.0004 ± 0.0001 0.0006 ± 0.0001 < 0.0001 ± 0 0.0006 ± 0.0001 0.0003 ± 0.0002

U μg/L 0.87 ± 0.04 0.54 ± 0.02 1.09 ± 0.05 0.47 ± 0.02 1.01 ± 0.05

V μg/L 5.4 ± 0.2 2.4 ± 0.2 5.6 ± 0.5 2.1 ± 0.2 4.7 ± 0.3

Y μg/L 0.018 ± 0.001 0.034 ± 0 0.017 ± 0 0.029 ± 0 0.014 ± 0.001

Yb μg/L 0.0019 ± 0.0001 0.0041 ± 0.0009 0.002 ± 0.0002 0.0037 ± 0.0004 0.0019 ± 0.0003

Zn μg/L 20 ± 1 5.3 ± 0.2 19 ± 1 4.3 ± 0.2 24 ± 2

Zr μg/L 0.029 ± 0.001 0.026 ± 0.003 0.044 ± 0.001 0.026 ± 0.003 0.043 ± 0.002

67
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 4-5. Continued. 

Element 

Concentration 

Unit 

Hayfield 2 

Outlet 

8/4/98 

Hayfield 

Inlet 

8/10/98 

Hayfield 2 

Outlet 

8/10/98 

Hayfield 

Inlet 

8/18/98 

Hayfield 2 

Outlet 

8/18/98 

Al μg/L 4.9 ± 1.4 11 ± 1 1.6 ± 0.2 7 ± 0.7 22 ± 1

As μg/L 4.5 ± 0 3.2 ± 0 3.7 ± 0 4 ± 0 4.3 ± 0

B μg/L 407 ± 0 455 ± 3 399 ± 3 388 ± 6 407 ± 4

Ba μg/L 26 ± 1 22 ± 1 28 ± 0 20 ± 0 29 ± 0

Be μg/L 0.01 ± 0.003 < 0.008 ± 0.008 0.008 ± 0.003 < 0.008 ± 0.002 0.015 ± 0.006

Bi μg/L 0.012 ± 0.001 0.006 ± 0 0.003 ± 0.001 0.006 ± 0.002 0.003 ± 0

Cd μg/L < 0.002 ± 0.003 < 0.002 ± 0.006 < 0.002 ± 0.005 < 0.002 ± 0.003 < 0.002 ± 0.005

Ce μg/L 0.033 ± 0.003 0.019 ± 0.001 0.031 ± 0 0.02 ± 0 0.069 ± 0

Co μg/L 0.32 ± 0.01 0.22 ± 0 0.32 ± 0.03 0.42 ± 0.05 0.49 ± 0

Cr μg/L 0.7 ± 0.3 0.7 ± 0.2 0.4 ± 0.1 0.7 ± 0.2 0.7 ± 0.2

Cs μg/L 0.069 ± 0.001 0.081 ± 0.002 0.064 ± 0.001 0.099 ± 0.002 0.053 ± 0.002

Cu μg/L < 0.06 ± 0.06 0.63 ± 0.04 < 0.06 ± 0.01 0.8 ± 0.05 < 0.06 ± 0.1

Dy μg/L 0.0048 ± 0.0008 0.0024 ± 0.0007 0.0041 ± 0.0003 0.0028 ± 0 0.0067 ± 0.001

Er μg/L 0.0038 ± 0 0.002 ± 0.0007 0.0037 ± 0.0003 0.0022 ± 0.0002 0.0057 ± 0.0003

Eu μg/L 0.0015 ± 0.0006 0.0014 ± 0.0004 0.0026 ± 0.0011 0.0012 ± 0.0004 0.0023 ± 0.0006

Fe μg/L 71 ± 1 85 ± 0 91 ± 0 83 ± 0 107 ± 0

Gd μg/L 0.028 ± 0.001 0.012 ± 0 0.057 ± 0.003 0.044 ± 0 0.03 ± 0

Ho μg/L 0.0018 ± 0.0001 0.0011 ± 0.0001 0.0016 ± 0.0001 0.0011 ± 0.0001 0.002 ± 0.0001

La μg/L 0.0079 ± 0.0005 0.0062 ± 0 0.0068 ± 0.0003 0.005 ± 0.0001 0.026 ± 0.001

Li μg/L 105 ± 6 104 ± 0 110 ± 2 113 ± 2 108 ± 1

Lu μg/L 0.0007 ± 0.0001 0.0005 ± 0.0001 0.0005 ± 0.0001 0.0004 ± 0.0001 0.001 ± 0.0003

Mn μg/L 79 ± 1 28 ± 0 67 ± 2 34 ± 0 110 ± 1

Mo μg/L 20 ± 0 23 ± 1 25 ± 1 27 ± 1 20 ± 1

Nd μg/L 0.017 ± 0.001 0.01 ± 0.001 0.015 ± 0 0.008 ± 0.001 0.033 ± 0

Ni μg/L 3.1 ± 0.3 2.6 ± 0.4 4 ± 0.4 4.4 ± 0.5 3.6 ± 0.2

Pb μg/L 0.05 ± 0.01 0.08 ± 0 0.05 ± 0 0.14 ± 0.01 0.07 ± 0

Pr μg/L 0.0035 ± 0.0004 0.0023 ± 0.0002 0.0032 ± 0.0001 0.002 ± 0.0001 0.0083 ± 0.0006

Rb μg/L 15 ± 0 14 ± 0 15 ± 1 16 ± 0 14 ± 1

Re μg/L 0.085 ± 0 0.082 ± 0.005 0.088 ± 0.001 0.086 ± 0.004 0.082 ± 0.003

Sb μg/L 0.41 ± 0.01 0.66 ± 0 0.45 ± 0 0.67 ± 0.01 0.49 ± 0.01

Se μg/L < 0.09 ± 0.11 0.16 ± 0.17 0.24 ± 0.02 0.35 ± 0.18 < 0.09 ± 0.01

Sm μg/L 0.004 ± 0 0.002 ± 0.001 0.003 ± 0.001 0.002 ± 0.001 0.007 ± 0.001

Sr μg/L 687 ± 10 663 ± 5 733 ± 14 695 ± 1 686 ± 16

Tb μg/L 0.0009 ± 0.0002 0.0008 ± 0 0.0009 ± 0 0.0006 ± 0.0001 0.0015 ± 0.0001

Te μg/L 0.04 ± 0 0.027 ± 0.005 0.034 ± 0.002 0.028 ± 0.002 0.039 ± 0.001

Th μg/L 0.0011 ± 0.0004 0.0005 ± 0.0003 0.001 ± 0.0005 0.0003 ± 0.0002 0.0006 ± 0.0002

Tl μg/L < 0.001 ± 0.001 0.002 ± 0.002 < 0.001 ± 0.001 0.002 ± 0.001 0.002 ± 0.001

Tm μg/L 0.0007 ± 0.0001 0.0004 ± 0.0001 0.0005 ± 0.0001 0.0003 ± 0.0001 0.0009 ± 0.0001

U μg/L 0.45 ± 0.01 1.06 ± 0.03 0.66 ± 0.04 0.65 ± 0.04 0.6 ± 0.02

V μg/L 3.1 ± 0 5.8 ± 0.5 2.2 ± 0 5.1 ± 0.5 3.2 ± 0.2

Y μg/L 0.025 ± 0 0.014 ± 0 0.027 ± 0.001 0.015 ± 0 0.035 ± 0

Yb μg/L 0.0044 ± 0.0001 0.0021 ± 0.0005 0.0035 ± 0.0002 0.0026 ± 0.0003 0.0055 ± 0.0009

Zn μg/L 15 ± 0 15 ± 1 10 ± 0 20 ± 2 4.4 ± 0.2

Zr μg/L 0.028 ± 0.001 0.036 ± 0.004 0.025 ± 0.001 0.033 ± 0.002 0.05 ± 0.009

68
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 4-6. Summary of duplicate trace element results for water samples collected from the Cobble 

wetlands inlet, Cobble 2 wetland outlet, and the Gila River at Bullard Avenue during June 1999, and from 

the Cobble wetlands inlet, Cobble 1 and Cobble 2 wetlands outlet, Hayfield wetlands inlet, Hayfield 1 and 

Hayfield 2 wetlands outlets, the Gila River at 115th and Bullard Avenues, and the 91st Avenue dewatering 

well during February 2000. [ND, not determined] 

Element

Concentration 

Unit 

Cobble 

Inlet 

6/23/99 

Cobble 

Inlet 

6/23/99 

Cobble 2 

Outlet 

6/23/99 

Cobble 2 

Outlet 

6/23/99 

Bullard 

Avenue 

6/23/99 

Bullard 

Avenue 

6/23/99 

Al μg/L 9 ± 0.5 9.7 ± 0.3 2.4 ± 0.1 1.4 ± 0 103 ± 3 1.7 ± 0.3

As μg/L 3.9 ± 0.1 5 ± 0 3.5 ± 0.2 5 ± 0.1 8.4 ± 0 8.3 ± 0

B μg/L 468 ± 13 450 ± 30 476 ± 17 432 ± 7 589 ± 11 591 ± 10

Ba μg/L 20 ± 0 19 ± 0 24 ± 1 23 ± 0 48 ± 1 46 ± 0

Be μg/L < 0.01± 0 < 0.01± 0.01 < 0.01 ± 0.01 < 0.01± 0 < 0.01± 0.01 < 0.01± 0

Bi μg/L 0.014 ± 0 0.009 ± 0.003 0.045 ± 0.002 0.01 ± 0 0.0072 ± 0.0011 0.012 ± 0

Cd μg/L 0.005 ± 0.001 0.031 ± 0.004 0.047 ± 0.005 0.005 ± 0.004 0.004 ± 0.01 < 0.002 ± 0.007

Ce μg/L 0.021 ± 0.001 0.017 ± 0 0.037 ± 0.001 0.022 ± 0.001 0.3 ± 0.01 0.011 ± 0

Co μg/L 0.24 ± 0.01 0.34 ± 0.01 0.34 ± 0.01 0.22 ± 0.02 0.55 ± 0.01 0.44 ± 0.04

Cr μg/L 0.6 ± 0.2 0.5 ± 0.1 0.5 ± 0.1 0.6 ± 0 1.1 ± 0.1 1.1 ± 0.1

Cs μg/L 0.12 ± 0 0.13 ± 0 0.082 ± 0.003 0.088 ± 0.001 0.076 ± 0.002 0.062 ± 0.002

Cu μg/L 1.1 ± 0 0.97 ± 0.09 0.58 ± 0.06 0.62 ± 0.25 2.6 ± 0.1 2.2 ± 0

Dy μg/L 0.0024 ± 0.0007 0.0017 ± 0.0003 0.0041 ± 0.0007 0.0045 ± 0.0004 0.016 ± 0.001 0.0031 ± 0.001

Er μg/L 0.002 ± 0.0013 0.0021 ± 0.0001 0.0032 ± 0.0005 0.0043 ± 0.0005 0.011 ± 0.001 0.0035 ± 0.0007

Eu μg/L 0.0009 ± 0.0012 < 0.0002 ± 0.0005 0.0006 ± 0.0011 0.0011 ± 0.001 0.0061 ± 0.0008 0.0008 ± 0.0018

Fe μg/L 70 ± 20 88 ± 2 65 ± 3 58 ± 4 170 ± 10 7.8 ± 1

Gd μg/L 0.11 ± 0 0.12 ± 0 0.043 ± 0.001 0.04 ± 0.002 0.058 ± 0.001 0.041 ± 0.001

Hg ng/L ND ND ND ND ND ND

Ho μg/L 0.0013 ± 0.0001 0.0011 ± 0.0001 0.0017 ± 0.0001 0.0018 ± 0.0002 0.0039 ± 0.0004 0.0019 ± 0.0001

La μg/L 0.006 ± 0 0.004 ± 0 0.01 ± 0 0.006 ± 0 0.14 ± 0 0.006 ± 0

Li μg/L 92 ± 1 96 ± 0 89 ± 0 91 ± 1 130 ± 10 130 ± 10

Lu μg/L 0.0005 ± 0.0001 0.0006 ± 0 0.0009 ± 0.0001 0.0007 ± 0 0.0017 ± 0.0002 0.0011 ± 0.0001

Mn μg/L 26 ± 0 27 ± 1 30 ± 1 11 ± 0 62 ± 1 2.2 ± 0

Mo μg/L 21 ± 0 23 ± 0 17 ± 0 17 ± 0 17 ± 0 17 ± 0

Nd μg/L 0.0064 ± 0.001 0.0076 ± 0.0003 0.017 ± 0.001 0.014 ± 0.002 0.14 ± 0 0.0099 ± 0.0017

Ni μg/L 7.2 ± 0.4 6.2 ± 0.1 4.1 ± 0.4 4.7 ± 0.5 5.6 ± 0.6 5.3 ± 0.7

Pb μg/L 0.16 ± 0 0.15 ± 0.01 0.096 ± 0.001 0.098 ± 0.002 0.21 ± 0.01 0.083 ± 0.002

Pr μg/L 0.0019 ± 0.0001 0.0016 ± 0.0003 0.0037 ± 0.0003 0.0033 ± 0.0006 0.033 ± 0 0.0021 ± 0.0003

Rb μg/L 14 ± 0 14 ± 0 13 ± 0 13 ± 0 12 ± 0 11 ± 0

Re μg/L 0.091 ± 0 0.1 ± 0 0.13 ± 0 0.13 ± 0 0.11 ± 0 0.11 ± 0

Sb μg/L 0.55 ± 0 0.56 ± 0.01 0.38 ± 0.02 0.4 ± 0 0.47 ± 0 0.47 ± 0.01

Se μg/L 0.2 ± 0.2 1.2 ± 0.1 1 ± 0.1 < 0.2 ± 0.2 0.4 ± 0.1 0.5 ± 0.2

Sm μg/L 0.0013 ± 0.0004 0.0014 ± 0.0005 0.0033 ± 0.0011 0.0038 ± 0.0007 0.026 ± 0 0.0025 ± 0.0002

Sr μg/L 780 ± 10 810 ± 10 830 ± 0 800 ± 10 1300 ± 0 1200 ± 0

Ta μg/L < 0.003 ± 0.004 < 0.002 ± 0.002 < 0.002 ± 0.001 < 0.003 ± 0.002 < 0.003 ± 0.002 < 0.003 ± 0.003

Tb μg/L 0.0009 ± 0.0001 0.0006 ± 0 0.0009 ± 0 0.0012 ± 0.0001 0.0035 ± 0.0003 0.0011 ± 0.0003

Te μg/L 0.035 ± 0.001 0.037 ± 0.015 0.029 ± 0.005 0.046 ± 0.001 0.05 ± 0.002 0.048 ± 0.005

Th μg/L 0.0024 ± 0.0016 < 0.0008 ± 0.0005 0.0011 ± 0.0006 0.0029 ± 0.0009 0.016 ± 0.001 0.0017 ± 0

Tl μg/L < 0.002 ± 0.001 < 0.002 ± 0.001 < 0.002 ± 0.001 < 0.002 ± 0.003 < 0.002 ± 0.002 < 0.002 ± 0.002

Tm μg/L 0.0002 ± 0.0001 0.0003 ± 0 0.0004 ± 0.0001 0.0008 ± 0.0001 0.0014 ± 0.0001 0.0005 ± 0.0001

U μg/L 1.5 ± 0 1.6 ± 0 0.66 ± 0.01 0.66 ± 0 4.1 ± 0.1 4.1 ± 0

V μg/L 5.4 ± 0.3 4.2 ± 0.1 1.2 ± 0.2 2.7 ± 0.1 8.9 ± 0.1 8.7 ± 0

Y μg/L 0.017 ± 0 0.016 ± 0.001 0.029 ± 0.002 0.028 ± 0 0.092 ± 0 0.026 ± 0.001

Yb μg/L 0.0027 ± 0.0004 0.0027 ± 0.0003 0.0036 ± 0.0004 0.0039 ± 0.0003 0.0094 ± 0.0007 0.0045 ± 0.0008

Zn μg/L 14 ± 0 14 ± 0 6.8 ± 0.1 6.4 ± 0.2 9.2 ± 0.1 8.5 ± 0

Zr μg/L 0.023 ± 0.001 0.022 ± 0.001 0.013 ± 0.001 0.017 ± 0.002 0.053 ± 0.002 0.023 ± 0.001

69
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 4-6. Continued. 

Element

Concentration 

Unit 

Cobble 

Inlet 

2/14/00 

Cobble 

Inlet 

2/14/00 

Cobble 1 

Outlet 

2/14/00 

Cobble 1 

Outlet 

2/14/00 

Cobble 2 

Outlet 

2/14/00 

Cobble 2 

Outlet 

2/14/00 

Al μg/L 6.7 ± 0.4 6.7 ± 0.1 3.0 ± 0.2 3.0 ± 0.2 7.5 ± 0.4 4.6 ± 0.4

As μg/L 5.5 ± 0.4 5.4 ± 0.3 5.7 ± 0 5.1 ± 0.3 5.1 ± 0.3 4.7 ± 0.1

B μg/L 606 ± 1 653 ± 71 554 ± 84 560 ± 40 569 ± 69 570 ± 20

Ba μg/L 18 ± 1 18 ± 1 14 ± 1 14 ± 0 14 ± 1 14 ± 0

Be μg/L < 0.007 ± 0.001 < 0.007 ± 0.002 < 0.007 ± 0.001 < 0.007 ± 0.003 < 0.007 ± 0.003 < 0.007 ± 0.003

Bi μg/L 0.009 ± 0.001 0.016 ± 0.003 0.009 ± 0.001 0.011 ± 0.001 0.005 ± 0.002 0.012 ± 0.009

Cd μg/L 0.007 ± 0.017 0.009 ± 0.009 < 0.003 ± 0.003 < 0.003 ± 0.031 0.037 ± 0.012 0.025 ± 0.002

Ce μg/L 0.013 ± 0.001 0.012 ± 0.001 0.016 ± 0.001 0.017 ± 0 0.035 ± 0.001 0.028 ± 0.001

Co μg/L 0.027 ± 0.106 0.051 ± 0.075 0.19 ± 0.1 0.19 ± 0.09 0.30 ± 0.06 0.32 ± 0.1

Cr μg/L 0.6 ± 0.1 0.5 ± 0 0.4 ± 0 0.4 ± 0.1 < 0.4 ± 0 0.4 ± 0.1

Cs μg/L < 0.03 ± 0.01 < 0.03 ± 0.03 < 0.03 ± 0.01 < 0.03 ± 0.01 < 0.03 ± 0.04 < 0.03 ± 0.02

Cu μg/L 1.9 ± 0.1 1.8 ± 0.1 1.6 ± 0.1 1.7 ± 0.1 1.1 ± 0.1 0.91 ± 0.03

Dy μg/L 0.0015 ± 0.0002 0.002 ± 0.0004 0.0021 ± 0.0003 0.0023 ± 0.0003 0.0036 ± 0.0001 0.0032 ± 0.0004

Er μg/L 0.0017 ± 0.0001 0.0018 ± 0.0002 0.0017 ± 0.0002 0.0018 ± 0.0003 0.0028 ± 0.0002 0.0025 ± 0.0007

Eu μg/L < 0.0002 ± 0.0029< 0.0002 ± 0.0015< 0.0002 ± 0.0018< 0.0002 ± 0.0022 0.0013 ± 0.0005 0.0009 ± 0.0024

Fe μg/L 82 ± 0 79 ± 1 40 ± 1 40 ± 1 81 ± 2 71 ± 2

Gd μg/L 0.02 ± 0.002 0.019 ± 0.002 0.12 ± 0.01 0.12 ± 0.01 0.10 ± 0.01 0.099 ± 0.005

Hg ng/L 1.3 ± 0.2 0.9 ± 0.3 0.6 ± 0.2 0.5 ± 0.1 < 0.4 ± 0.1 < 0.4 ± 0.2

Ho μg/L 0.0008 ± 0.0001 0.0007 ± 0.0002 0.0007 ± 0.0002 0.0008 ± 0.0002 0.0012 ± 0.0001 0.0011 ± 0.0002

La μg/L 0.005 ± 0 0.004 ± 0 0.005 ± 0 0.005 ± 0 0.014 ± 0.001 0.011 ± 0

Li μg/L 66 ± 2 65 ± 1 63 ± 0 62 ± 1 59 ± 1 59 ± 0

Lu μg/L 0.0005 ± 0.0001 0.0005 ± 0 0.0003 ± 0 0.0005 ± 0.0001 0.0005 ± 0.0001 0.0006 ± 0

Mn μg/L 24 ± 2 24 ± 1 16 ± 1 16 ± 1 27 ± 2 28 ± 1

Mo μg/L 11 ± 0 11 ± 0 19 ± 0 18 ± 1 17 ± 0 16 ± 0

Nd μg/L 0.005 ± 0.001 0.006 ± 0.001 0.006 ± 0 0.007 ± 0.001 0.015 ± 0.001 0.012 ± 0.000

Ni μg/L 3.7 ± 0.6 4.3 ± 0.3 5.8 ± 0.3 6.1 ± 0.2 6.5 ± 0.4 6.2 ± 0.4

Pb μg/L 0.17 ± 0.01 0.17 ± 0.02 0.2 ± 0.01 0.21 ± 0 0.20 ± 0 0.20 ± 0.03

Pr μg/L 0.0014 ± 0.0002 0.0013 ± 0.0002 0.0016 ± 0.0003 0.0016 ± 0.0001 0.0036 ± 0 0.0030 ± 0.0001

Rb μg/L 13 ± 0 13 ± 0 13 ± 0 13 ± 0 13 ± 0 13 ± 0

Re μg/L 0.059 ± 0.002 0.057 ± 0.003 0.064 ± 0.001 0.07 ± 0.001 0.058 ± 0.001 0.064 ± 0.001

Sb μg/L 0.43 ± 0.01 0.43 ± 0.01 0.59 ± 0.01 0.57 ± 0.03 0.52 ± 0.01 0.52 ± 0.1

Se μg/L 1.1 ± 0.6 0.9 ± 0 0.6 ± 0.2 1 ± 0.5 0.9 ± 0.2 1.4 ± 0.2

Sm μg/L 0.0013 ± 0.0005 0.0013 ± 0.0001 0.0016 ± 0.0002 0.0018 ± 0.0002 0.0033 ± 0.0003 0.0026 ± 0.0005

Sr μg/L 736 ± 5 721 ± 12 802 ± 19 791 ± 20 750 ± 20 791 ± 13

Ta μg/L < 0.002 ± 0.001 < 0.002 ± 0.001 < 0.002 ± 0.001 < 0.002 ± 0 < 0.002 ± 0.001 < 0.002 ± 0

Tb μg/L 0.0006 ± 0.0001 0.0005 ± 0.0001 0.0005 ± 0.0002 0.0008 ± 0 0.0008 ± 0.0002 0.0010 ± 0

Te μg/L 0.031 ± 0.001 0.026 ± 0.003 0.021 ± 0.004 0.025 ± 0.007 0.019 ± 0.005 0.025 ± 0.005

Th μg/L 0.0011 ± 0.0004 0.0013 ± 0.0006 0.0023 ± 0.0016 0.001 ± 0.0005 0.0032 ± 0.001 0.0037 ± 0.0016

Tl μg/L 0.005 ± 0.003 0.004 ± 0.003 < 0.003 ± 0 < 0.003 ± 0.002 < 0.003 ± 0.002 0.023 ± 0.004

Tm μg/L 0.0003 ± 0 0.0003 ± 0.0001 0.0003 ± 0 0.0003 ± 0 0.0004 ± 0.0001 0.0004 ± 0.0001

U μg/L 2.6 ± 0.1 2.6 ± 0.1 2.3 ± 0.1 2.4 ± 0.1 2.2 ± 0.1 2.4 ± 0.1

V μg/L 3.1 ± 0.2 3.1 ± 0.1 4.5 ± 0.2 4.4 ± 0.1 4.2 ± 0.1 4.0 ± 0

Y μg/L 0.019 ± 0.001 0.017 ± 0.001 0.021 ± 0.001 0.022 ± 0.002 0.032 ± 0.003 0.031 ± 0.001

Yb μg/L 0.0024 ± 0.0006 0.0024 ± 0.0003 0.002 ± 0.0005 0.0022 ± 0.0008 0.0029 ± 0.0002 0.0040 ± 0.0004

Zn μg/L 22 ± 0 22 ± 0 22 ± 1 20 ± 0 16 ± 1 16 ± 1

Zr μg/L 0.047 ± 0.001 0.044 ± 0.002 0.042 ± 0.001 0.04 ± 0.001 0.039 ± 0.003 0.036 ± 0.002

70
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 4-6. Continued. 

Element 

Concentration 

Unit 

Hayfield 

Inlet 

2/15/00 

Hayfield 

Inlet 

2/15/00 

Hayfield 1 

Outlet 

2/15/00 

Hayfield 1 

Outlet 

2/15/00 

Hayfield 2 

Outlet 

2/15/00 

Hayfield 2 

Outlet 

2/15/00 

Al μg/L 7 ± 3 3 ± 4 14 ± 5 10 ± 4 3 ± 4 7 ± 4

As μg/L 4.1 ± 0.1 4.8 ± 0.2 5.3 ± 0 5.4 ± 0.4 5.6 ± 0.1 5.3 ± 0.6

B μg/L 510 ± 0 570 ± 10 570 ± 20 550 ± 20 560 ± 20 560 ± 50

Ba μg/L 15 ± 0 15 ± 0 10 ± 0 9.5 ± 0.2 8.2 ± 0.4 8.7 ± 0.3

Be μg/L < 0.01 ± 0.01 0.01 ± 0.01 < 0.01 ± 0 < 0.01 ± 0 < 0.01 ± 0.01 < 0.01 ± 0

Bi μg/L 0.017 ± 0.002 0.017 ± 0.002 0.0059 ± 0.0022 0.0027 ± 0.0007 0.0042 ± 0.0021 0.0042 ± 0.0013

Cd μg/L 0.04 ± 0.01 0.01 ± 0.03 < 0.09 ± 0.09 0.06 ± 0.06 0.14 ± 0.06 < 0.01 ± 0.01

Ce μg/L 0.011 ± 0.001 0.011 ± 0 0.12 ± 0 0.1 ± 0 0.057 ± 0.005 0.09 ± 0.002

Co μg/L 0.2 ± 0.02 0.20 ± 0.1 0.34 ± 0.01 0.32 ± 0.01 0.21 ± 0.01 0.22 ± 0

Cr μg/L < 0.4 ± 0.4 < 0.4 ± 0.6 < 0.4 ± 0.2 < 0.4 ± 0.2 < 0.4 ± 0 < 0.4 ± 0.6

Cs μg/L 0.11 ± 0.01 0.12 ± 0 0.06 ± 0.02 0.03 ± 0.02 0.12 ± 0.01 0.02 ± 0.01

Cu μg/L 1.8 ± 0 1.8 ± 0.1 1.7 ± 0 1.1 ± 0.2 1.6 ± 0.1 1.5 ± 0.1

Dy μg/L 0.0013 ± 0.0002 0.0012 ± 0.0003 0.0068 ± 0.0005 0.0065 ± 0.0012 0.0042 ± 0.001 0.0057 ± 0.0002

Er μg/L 0.0012 ± 0.0001 0.0012 ± 0.0002 0.0052 ± 0.0008 0.0039 ± 0.0004 0.004 ± 0.0009 0.0047 ± 0.0007

Eu μg/L 0.0003 ± 0.0003 0.0002 ± 0.0005 0.0021 ± 0.0005 0.0022 ± 0.0006 0.0011 ± 0.0002 0.0018 ± 0.0003

Fe μg/L 86 ± 15 84 ± 27 59 ± 6 53 ± 2 37 ± 2 57 ± 3

Gd μg/L 0.073 ± 0.003 0.072 ± 0 0.086 ± 0.004 0.081 ± 0.002 0.062 ± 0.002 0.067 ± 0

Hg ng/L ND ND ND ND ND ND

Ho μg/L 0.0006 ± 0.0001 0.0006 ± 0.0001 0.0019 ± 0.0001 0.0016 ± 0.0002 0.0013 ± 0.0001 0.0015 ± 0.0003

La μg/L 0.0035 ± 0.0009 0.0025 ± 0.0005 0.049 ± 0 0.041 ± 0 0.019 ± 0.001 0.035 ± 0

Li μg/L 51 ± 2 53 ± 1 53 ± 2 53 ± 0 53 ± 4 53 ± 1

Lu μg/L 0.0003 ± 0.0001 0.0003 ± 0 0.0008 ± 0.0002 0.0008 ± 0 0.0009 ± 0 0.0009 ± 0

Mn μg/L 23 ± 1 21 ± 1 18 ± 1 14 ± 1 6.1 ± 0.5 7.2 ± 0.5

Mo μg/L 13 ± 0 13 ± 0 14 ± 0 14 ± 0 16 ± 0 17 ± 0

Nd μg/L 0.0060 ± 0.0015 0.0055 ± 0.0003 0.049 ± 0.004 0.044 ± 0.004 0.021 ± 0 0.036 ± 0.001

Ni μg/L 6.2 ± 0.3 6.1 ± 0.1 6.2 ± 0.1 5.6 ± 0.2 5.6 ± 0.1 5.5 ± 0.1

Pb μg/L 0.21 ± 0 0.21 ± 0 0.18 ± 0.01 0.13 ± 0.02 0.13 ± 0.01 0.13 ± 0.01

Pr μg/L 0.0013 ± 0.0004 0.0012 ± 0.0002 0.013 ± 0 0.011 ± 0 0.0051 ± 0.0003 0.009 ± 0.0004

Rb μg/L 11 ± 0 12 ± 0 12 ± 0 11 ± 0 11 ± 0 11 ± 0

Re μg/L 0.090 ± 0.003 0.093 ± 0.004 0.061 ± 0.003 0.061 ± 0 0.059 ± 0.002 0.058 ± 0.001

Sb μg/L 0.42 ± 0 0.44 ± 0.01 0.47 ± 0.01 0.46 ± 0.01 0.54 ± 0.01 0.55 ± 0.03

Se μg/L 0.22 ± 0.05 0.42 ± 0.13 0.33 ± 0.12 0.32 ± 0.05 0.35 ± 0.14 0.37 ± 0.06

Sm μg/L 0.0015 ± 0.0007 0.0012 ± 0.0008 0.0089 ± 0.001 0.0083 ± 0.0007 0.0077 ± 0.0004 0.0071 ± 0.0005

Sr μg/L 700 ± 10 730 ± 10 750 ± 0 740 ± 10 710 ± 0 730 ± 0

Ta μg/L < 0.001 ± 0 < 0.001 ± 0.001 < 0.001 ± 0.001 < 0.001 ± 0 0.003 ± 0.002 0.003 ± 0.003

Tb μg/L 0.0003 ± 0.0001 0.0004 ± 0 0.0015 ± 0.0001 0.0013 ± 0.0002 0.0008 ± 0.0001 0.0011 ± 0.0001

Te μg/L 0.023 ± 0.008 0.016 ± 0.001 0.022 ± 0.009 0.017 ± 0.004 0.017 ± 0.003 0.019 ± 0.006

Th μg/L 0.0023 ± 0.0011 0.0015 ± 0.0009 0.0066 ± 0.0018 0.0047 ± 0.0007 0.011 ± 0.009 0.005 ± 0.0013

Tl μg/L < 0.01 ± 0.01 < 0.01 ± 0.01 < 0.01 ± 0 < 0.01 ± 0 < 0.01 ± 0.01 < 0.01 ± 0.01

Tm μg/L < 0.0001 ± 0.0001 0.0002 ± 0.0001 0.0007 ± 0.0001 0.0007 ± 0.0002 0.0006 ± 0.0001 0.0008 ± 0.0002

U μg/L 1.9 ± 0 1.9 ± 0 1.8 ± 0 1.8 ± 0 2.5 ± 0 2.5 ± 0.1

V μg/L 4.0 ± 0.5 4.5 ± 0.2 5.9 ± 0.3 5.6 ± 0.3 7 ± 0.2 6.5 ± 0

Y μg/L 0.013 ± 0.001 0.031 ± 0 0.044 ± 0.001 0.043 ± 0.001 0.029 ± 0 0.039 ± 0.002

Yb μg/L 0.0016 ± 0.0001 0.0019 ± 0.0004 0.0056 ± 0.0006 0.0048 ± 0.0004 0.0046 ± 0.0003 0.0052 ± 0.0004

Zn μg/L 14 ± 1 14 ± 1 10 ± 0 9.9 ± 0.9 12 ± 0 12 ± 1

Zr μg/L 0.058 ± 0.032 0.025 ± 0.002 0.047 ± 0.017 0.028 ± 0.004 0.041 ± 0.013 0.03 ± 0.004

71
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 4-6. Continued. 

Element 

Concentration 

Unit 

Bullard 

Avenue 

2/13/00 

Bullard 

Avenue 

2/13/00 

115th

Avenue 

2/13/00 

115th

Avenue 

2/13/00 

91st Avenue 

Well 

2/16/00 

Al μg/L 48 ± 1 35 ± 0 15 ± 2 22 ± 2 < 10 ± 11

As μg/L 6.2 ± 0 7.3 ± 0.1 6.7 ± 0.9 6.8 ± 1 10 ± 1

B μg/L 614 ± 7 604 ± 3 747 ± 35 760 ± 31 570 ± 10

Ba μg/L 46 ± 1 46 ± 3 34 ± 1 35 ± 1 57 ± 1

Be μg/L 0.009 ± 0 < 0.007 ± 0.001 < 0.007 ± 0.003 0.008 ± 0.002 < 0.01 ± 0.01

Bi μg/L 0.041 ± 0.03 0.007 ± 0.005 0.009 ± 0.002 0.017 ± 0.002 0.015 ± 0.001

Cd μg/L 0.015 ± 0.01 < 0.003 ± 0.009 < 0.003 ± 0.007 < 0.003 ± 0.003 0.02 ± 0.01

Ce μg/L 0.13 ± 0 0.094 ± 0.004 0.031 ± 0.002 0.044 ± 0.002 0.011 ± 0

Co μg/L 0.56 ± 0.11 0.44 ± 0.08 0.18 ± 0.19 0.14 ± 0.22 1.1 ± 0

Cr μg/L 1.8 ± 0.1 1.8 ± 0.1 < 0.4 ± 0.1 0.4 ± 0.1 < 0.4 ± 1.6

Cs μg/L < 0.03 ± 0.06 < 0.03 ± 0.03 < 0.03 ± 0.01 < 0.03 ± 0.01 0.14 ± 0.02

Cu μg/L 1.6 ± 0.2 1.7 ± 0.1 1.2 ± 0.1 1.2 ± 0 8.2 ± 0.1

Dy μg/L 0.0088 ± 0.0008 0.0062 ± 0.0005 0.0033 ± 0 0.0045 ± 0.0002 0.0026 ± 0.0002

Er μg/L 0.0067 ± 0.0004 0.0059 ± 0.0006 0.0041 ± 0.0004 0.0046 ± 0.0005 0.0089 ± 0.0003

Eu μg/L 0.0041 ± 0.0034< 0.0002 ± 0.0027 < 0.0002 ± 0.0049< 0.0002 ± 0.0012 < 0.0001 ± 0.0002

Fe μg/L 68 ± 3 50 ± 2 49 ± 1 57 ± 1 19 ± 6

Gd μg/L 0.097 ± 0.009 0.1 ± 0 0.087 ± 0.009 0.09 ± 0.008 0.0036 ± 0.001

Hg ng/L 1 ± 0.2 <0.4 ± 0.2 0.8 ± 0.2 <0.4 ± 0.5 ND

Ho μg/L 0.0022 ± 0.0001 0.0018 ± 0 0.0015 ± 0.0001 0.0016 ± 0.0001 0.002 ± 0.0001

La μg/L 0.063 ± 0.003 0.045 ± 0.002 0.014 ± 0.001 0.02 ± 0.002 0.009 ± 0.0004

Li μg/L 113 ± 1 121 ± 7 165 ± 1 162 ± 1 160 ± 0

Lu μg/L 0.0018 ± 0.0002 0.0016 ± 0.0001 0.0014 ± 0 0.0015 ± 0.0002 0.0052 ± 0.0001

Mn μg/L 75 ± 0 77 ± 1 81 ± 6 84 ± 5 25 ± 1

Mo μg/L 12 ± 0 13 ± 0 12 ± 0 12 ± 1 2.9 ± 0.1

Nd μg/L 0.061 ± 0.003 0.043 ± 0.002 0.014 ± 0.001 0.02 ± 0.001 0.0058 ± 0.0006

Ni μg/L 5 ± 0.2 5.3 ± 0.4 4.7 ± 0.1 5.3 ± 0.5 ND

Pb μg/L 0.2 ± 0 0.18 ± 0.01 0.18 ± 0.01 0.18 ± 0.01 0.059 ± 0.006

Pr μg/L 0.015 ± 0 0.011 ± 0 0.0035 ± 0.0001 0.0051 ± 0.0002 0.0017 ± 0.0004

Rb μg/L 11 ± 0 11 ± 0 13 ± 0 12 ± 0 6 ± 0.1

Re μg/L 0.082 ± 0 0.081 ± 0.002 0.077 ± 0.002 0.077 ± 0.002 0.09 ± 0.001

Sb μg/L 0.36 ± 0.01 0.37 ± 0.01 0.37 ± 0 0.38 ± 0.01 0.056 ± 0.003

Se μg/L 2.2 ± 0.2 1.2 ± 0.2 0.8 ± 0.3 0.5 ± 0.2 < 0.09 ± 0.18

Sm μg/L 0.011 ± 0 0.0086 ± 0.001 0.0034 ± 0.0006 0.0047 ± 0.0001 0.0021 ± 0

Sr μg/L 1326 ± 1 1321 ± 1 1413 ± 27 1437 ± 15 580 ± 20

Ta μg/L < 0.002 ± 0 < 0.002 ± 0.001 < 0.002 ± 0 < 0.002 ± 0 < 0.001 ± 0.001

Tb μg/L 0.0017 ± 0.0001 0.0014 ± 0.0002 0.0011 ± 0.0003 0.001 ± 0.0003 0.0006 ± 0.0001

Te μg/L 0.023 ± 0.007 0.017 ± 0.001 0.037 ± 0 0.035 ± 0 0.015 ± 0.007

Th μg/L 0.011 ± 0.001 0.0063 ± 0.0004 0.0033 ± 0.0002 0.0047 ± 0.0011 0.0032 ± 0.0017

Tl μg/L 0.007 ± 0.003 0.007 ± 0.004 0.009 ± 0.001 0.008 ± 0.004 < 0.01 ± 0.01

Tm μg/L 0.0011 ± 0 0.0009 ± 0.0001 0.0006 ± 0.0001 0.0008 ± 0.0001 0.002 ± 0.0001

U μg/L 5.3 ± 0.1 5.3 ± 0.1 5.6 ± 0 5.7 ± 0 1.8 ± 0

V μg/L 6.5 ± 0 6.6 ± 0.3 4.8 ± 0.1 5 ± 0 10 ± 0

Y μg/L 0.06 ± 0.003 0.05 ± 0.002 0.039 ± 0.001 0.041 ± 0.001 0.041 ± 0.002

Yb μg/L 0.0096 ± 0.0006 0.0076 ± 0.0004 0.0064 ± 0.0008 0.0064 ± 0.0007 0.02 ± 0.001

Zn μg/L 11 ± 0 11 ± 0 12 ± 0 13 ± 1 0.66 ± 0.18

Zr μg/L 0.074 ± 0.002 0.065 ± 0.001 0.041 ± 0 0.045 ± 0.002 0.007 ± 0

72
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

0

5

10

15

20

25

30

35

40 a b

Bullard Ave 115th Ave Cobble Hayfield 91st Ave

 Well

ALUMINUM CONCENTRATION,

in micrograms per liter

 Inlet

 Outlet1

 Outlet2

Bullard Ave 115th Ave Cobble Hayfield 91st Ave

 Well

Less than

0

2

4

6

8

10

ARSENIC CONCENTRATION,

in micrograms per liter

 Inlet

 Outlet1

 Outlet2

0.00

0.02

0.04

0.06

0.08

c

Bullard Ave 115th Ave Cobble Hayfield 91st Ave

 Well

CADMIUM CONCENTRATION,

in micrograms per liter

 Inlet

 Outlet1

 Outlet2

Less than

0

1

2

3

4

5

6

7

8

9

d

Bullard Ave 115th Ave Cobble Hayfield 91st Ave

 Well

COPPER CONCENTRATION,

in micrograms per liter

 Inlet

 Outlet1

 Outlet2

0.00

0.05

0.10

0.15

0.20

0.25

0.30

e f

Bullard Ave 115th Ave Cobble Hayfield 91st Ave

 Well

Bullard Ave 115th Ave Cobble Hayfield 91st Ave

 Well

LEAD CONCENTRATION,

in micrograms per liter

 Inlet

 Outlet1

 Outlet2

0

5

10

15

20

25

ZINC CONCENTRATION,

in micrograms per liter

 Inlet

 Outlet1

 Outlet2

Figure 4-5. Plots of dissolved (a) aluminum, (b) arsenic, (c) cadmium, (d) copper, (e) lead, and (f) zinc 

concentrations in water samples collected from the Gila River at 115th and Bullard Avenues, the Cobble 

and Hayfield wetlands inlets and outlets, and the 91st Avenue dewatering well, February 2000. 

73
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

NUTRIENTS

 Table 4-7 lists the results for dissolved nutrients including nitrate, nitrite, ammonium, and 

orthophosphate in samples collected at the H2 wetland in July and August 1998. Results show 

that nitrate and nitrite values are always higher in the inlet samples than the corresponding outlet 

samples. No significant change was observed for concentrations of ammonium between the inlet 

and outlet sites. Values for all orthophosphate determinations were reported to be greater than 

0.7 milligrams of phosphorus per liter due to sample preservation problems. 

SEDIMENT 

 Results for duplicate elemental analyses of sediment samples collected from the inlet and 

outlet of the C2 wetland on June 23, 1999 are listed in table 4-8. In addition, results are reported 

for NIST Buffalo River Sediment Standard, SRM 2704 along with the reported certified values. 

BIOTA 

VEGETATION

Elemental composition data for Schoenoplectus tabernaemontani and Schoenoplectus 

americanus vegetation samples (culms) collected from the C2 wetland inlet and outlet, June 23, 

1998 are reported in table 4-9. All results are reported on a dry-weight basis. Analyses of NIST 

Apple Leaves Standard, SRM 1515 (Taylor, 2001) are listed with certified values. Bar graphs 

showing typical vegetation data for 6 elements are shown in figure 4-6. 

Table 4-7. Nutrient data for water samples collected from the Hayfield wetlands inlet and the Hayfield 2 

wetland outlet during July to August 1998. 

Compound 

Concentration

Unit 

Hayfield 

Inlet 

7/24/98 

Hayfield 2 

Outlet 

7/24/98 

Hayfield 

Inlet 

7/28/98 

Hayfield 2 

Outlet 

7/28/98 

Hayfield 

Inlet 

8/4/98 

NO3 mg N/L 2.26 ± 0.02 0.041 ± 0.009 2.27 ± 0 0.009 ± 0.003 0.62 ± 0

NO2 mg N/L 0.071 ± 0.001 0.034 ± 0.001 0.08 ± 0.001 0.004 ± 0.001 0.076 ± 0.001

NH4 mg N/L 0.97 ± 0.01 1.1 ± 0 1.2 ± 0 1.2 ± 0 1.1 ± 0

PO4 mg P/L > 0.7 ± 0 > 0.7 ± 0.77 > 0.7 ± 0 > 0.7 ± 0.39 > 0.7 ± 0

Compound 

Concentration

Unit 

Hayfield 2 

Outlet 

8/4/98 

Hayfield 

Inlet 

8/10/98 

Hayfield 2 

Outlet 

8/10/98 

Hayfield 

Inlet 

8/18/98 

Hayfield 2 

Outlet 

8/18/98 

NO3 mg N/L 0.03 ± 0.001 1.7 ± 0.02 0.1 ± 0 1.45 ± 0.01 0.024 ± 0

NO2 mg N/L 0.008 ± 0.002 0.1 ± 0 0.031 ± 0.001 0.024 ± 0 0.047 ± 0.001

NH4 mg N/L 1.0 ± 0 1.1 ± 0 0.6 ± 0 0.75 ± 0.01 0.62 ± 0

PO4 mg P/L > 0.7 ± 1.65 > 0.7 ± 0 > 0.7 ± 0.75 > 0.7 ± 0 > 0.7 ± 0.75

74
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 4-8. Trace-element composition data for duplicate sediment samples collected from the Cobble 2 

wetland inlet and outlet, June 23, 1998. [Values reported on a dry-weight basis; μg/g, microgram per 

gram; ng/g, nanogram per gram; analysis of Buffalo River Sediment Standard, SRM 2704, is listed with 

certified values (Taylor, 2001); ND, not determined] 

Element 

Concentration 

Unit 

Cobble 

Inlet 

Cobble 

Inlet 

Cobble 2 

Outlet 

Cobble 2 

Outlet 

SRM 2704 

Measured 

SRM 2704 

Certified 

As μg/g < 10 ± 1 ND 17 ± 3 < 20 ± 4 29 ± 2 23 ± 1 

Ba μg/g 690 ± 50 ND 830 ± 90 780 ± 60 440 ± 10 414 ± 12 

Be μg/g 1.5 ± 0 1.5 ± 0.1 2.2 ± 0.3 1.9 ± 0.3 1.7 ± 0 ND 

Bi μg/g 0.64 ± 0.07 0.64 ± 0.06 0.31 ± 0.05 0.36 ± 0.04 0.64 ± 0.08 ND 

Cd μg/g 0.1 ± 0 0.07 ± 0.02 0.17 ± 0.04 0.09 ± 0.07 3.5 ± 0.1 3.45 ± 0.22 

Ce μg/g 49 ± 3 47 ± 0 63 ± 1 67 ± 5 53 ± 6 72 

Co μg/g 10 ± 1 11 ± 1 16 ± 1 14 ± 1 13 ± 2 14 ± 0.6 

Cr μg/g 75 ± 5 81 ± 5 97 ± 4 91 ± 5 120 ± 10 135 ± 5 

Cs μg/g 4 ± 0 4 ± 0 4 ± 1 5 ± 0 4 ± 1 6 

Cu μg/g 37 ± 4 38 ± 3 44 ± 3 46 ± 3 100 ± 0 98.6 ± 5 

Dy μg/g 3.2 ± 0.3 2.9 ± 0 4.7 ± 0.1 3.9 ± 0.1 4.3 ± 0.4 6 

Er μg/g 1.9 ± 0.2 1.7 ± 0 2.8 ± 0.1 2.3 ± 0.1 2.7 ± 0 ND 

Eu μg/g 0.9 ± 0 0.9 ± 0 1.3 ± 0 1.3 ± 0 1.2 ± 0 1.3 

Ga μg/g 11 ± 0 12 ± 1 15 ± 0 13 ± 0 12 ± 2 15 

Gd μg/g 3.3 ± 0.2 3.3 ± 0.4 4.9 ± 0.1 4.5 ± 0.3 4.5 ± 0.8 ND 

Hg ng/g < 3 ± 4 < 4 ± 4 < 4 ± 5 < 5 ± 4 1342 ± 39 1470 ± 70 

Ho μg/g 0.61 ± 0.05 0.56 ± 0 0.9 ± 0 0.76 ± 0.01 0.82 ± 0.09 ND 

La μg/g 24 ± 2 24 ± 0 31 ± 1 32 ± 3 26 ± 3 29 

Li μg/g 32 ± 4 30 ± 1 40 ± 3 37 ± 5 44 ± 3 47.5 ± 4.1 

Lu μg/g 0.3 ± 0.03 0.26 ± 0 0.4 ± 0.01 0.34 ± 0 0.37 ± 0.04 0.6 

Mn μg/g 350 ± 20 360 ± 20 640 ± 10 620 ± 40 560 ± 20 555 ± 19 

Mo μg/g 1.7 ± 0.1 1.8 ± 0.1 2.2 ± 0.2 2 ± 0.2 4.5 ± 0.4 ND 

Nd μg/g 23 ± 2 22 ± 0 31 ± 0 31 ± 2 26 ± 3 ND 

Ni μg/g 31 ± 3 34 ± 5 45 ± 2 43 ± 4 43 ± 8 44.1 ± 3 

Pb μg/g 20 ± 2 18 ± 0 23 ± 0 21 ± 1 170 ± 20 161 ± 17 

Pr μg/g 6.0 ± 0.4 6.0 ± 0.5 8.2 ± 0.2 8.1 ± 0.7 6.7 ± 0.7 ND 

Rb μg/g 91 ± 10 82 ± 4 95 ± 5 99 ± 7 90 ± 8 100 

Re μg/g 0.002 ± 0.002 < 0.002 ± < 0.002 ± < 0.002 ± 0.006 ± 0.001 ND 

Sb μg/g 1.1 ± 0 1.1 ± 0 1.4 ± 0 1.2 ± 0.1 3.9 ± 0.4 3.79 ± 0.2 

Sc μg/g 11 ± 1 ND 13 ± 1 14 ± 1 13 ± 1 12 

Se μg/g 9 ± 1 10 ± 0 11 ± 1 12 ± 0 11 ± 1 1.12 ± 0.1 

Sm μg/g 4.2 ± 0.3 4 ± 0.1 6 ± 0.1 5.5 ± 0 5.3 ± 0.7 6.7 

Sr μg/g 300 ± 30 310 ± 20 360 ± 20 350 ± 30 110 ± 10 130 

Ta μg/g 1.4 ± 0.2 1.3 ± 0.1 2.1 ± 0.2 1.8 ± 0.2 1.5 ± 0.1 ND 

Tb μg/g 0.5 ± 0 0.49 ± 0.01 0.8 ± 0 0.67 ± 0.01 0.71 ± 0.08 ND 

Te μg/g 0.15 ± 0.01 0.14 ± 0.04 0.15 ± 0.02 0.28 ± 0 0.25 ± 0.01 ND 

Th μg/g 7 ± 1 6 ± 0 9 ± 0 9 ± 0 9 ± 0.8 9.2 

Tl μg/g 0.4 ± 0 0.3 ± 0.1 0.4 ± 0.1 0.4 ± 0 0.8 ± 0.2 1.06 ± 0.1 

Tm μg/g 0.29 ± 0.01 0.25 ± 0.01 0.4 ± 0.01 0.33 ± 0.01 0.37 ± 0.04 ND 

U μg/g 3 ± 0.3 2.8 ± 0.1 2.8 ± 0.1 2.9 ± 0.2 3.5 ± 0.1 3.13 ± 0.1 

V μg/g 94 ± 5 ND 130 ± 0 130 ± 10 120 ± 9 95 ± 4 

Y μg/g 16 ± 1 15 ± 1 23 ± 1 20 ± 2 20 ± 2 ND 

Yb μg/g 1.9 ± 0.2 1.7 ± 0 2.8 ± 0 2.3 ± 0 2.5 ± 0.3 2.8 

Zn μg/g 68 ± 4 72 ± 0 86 ± 2 82 ± 7 410 ± 50 438 ± 12 

Zr μg/g 100 ± 9 100 ± 6 110 ± 4 110 ± 9 130 ± 14 300 

75
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 4-9. Trace-element composition data for softstem (Schoenoplectus tabernaemontani) and Olney’s 

(Schoenoplectus americanus) bulrush samples collected from the Cobble 2 wetland inlet and outlet zones, 

June 23, 1998. [Values reported on a dry-weight basis; μg/g, microgram per gram; ng/g, nanogram per 

gram; wt%, weight percent; analysis of Apple Leaves Standard, SRM 1515, is listed with certified values 

(Taylor, 2001); ND, not determined] 

Element 

Concentration 

Unit 

Cobble 2 Inlet 

tabernaemontani

Cobble 2 Inlet 

americanus

Cobble 2 Outlet

tabernaemontani

Cobble 2 Outlet

americanus

SRM 1515 

Measured 

SRM 1515 

Certified 

Al μg/g 11 ± 3 49 ± 11 23 ± 8 17 ± 5 230 ± 10 286 ± 9

As μg/g 0.25 ± 0.05 0.16 ± 0.03 0.18 ± 0.03 0.65 ± 0.17 < 0.1 ± 0.1 0.04 ± 0.01

B μg/g 8 ± 11 11 ± 1 9 ± 4 23 ± 2 27 ± 9 27 ± 2

Ba μg/g 14 ± 1 15 ± 2 23 ± 1 8.6 ± 0.4 49 ± 2 49 ± 2

Be μg/g < 0.09 ± 0.01 < 0.09 ± 0.02 < 0.09 ± 0.04 < 0.09 ± 0.02 < 0.09 ± 0.02 ND

Bi μg/g < 0.01 ± 0 < 0.01 ± 0 < 0.01 ± 0 < 0.01 ± 0.02 < 0.01 ± 0 ND

Ca wt% 0.4 ± 0.03 0.3 ± 0.04 0.37 ± 0.07 0.35 ± 0.05 1.5 ± 0.1 1.53 ± 0.02

Cd μg/g 0.19 ± 0.06 < 0.02 ± 0.07 0.2 ± 0.07 0.5 ± 0.03 0.06 ± 0.02 0.013 ± 0.002

Ce μg/g 0.038 ± 0.01 0.12 ± 0.02 0.058 ± 0.01 0.058 ± 0.007 3.1 ± 0.1 3

Co μg/g 0.03 ± 0.01 0.03 ± 0.01 < 0.02 ± 0.01 < 0.02 ± 0.01 0.03 ± 0.01 0.09

Cr μg/g < 1 ± 1 < 1 ± 1 < 1 ± 1 < 1 ± 1 1.1 ± 0.4 0.3

Cs μg/g < 0.4 ± 0.4 < 0.4 ± 0.1 < 0.4 ± 0.3 < 0.4 ± 0.4 < 0.4 ± 0.1 ND

Cu μg/g 1.8 ± 0.4 4 ± 0.9 1.6 ± 0.4 1.2 ± 0.5 5.4 ± 0.3 5.64 ± 0.24

Dy μg/g < 0.005 ± 0.002 < 0.005 ± 0.007 < 0.005 ± 0.001 < 0.006 ± 0.003 1.7 ± 0 ND

Er μg/g < 0.006 ± 0.001 < 0.006 ± 0.001 < 0.006 ± 0.001 < 0.006 ± 0.002 0.54 ± 0.01 ND

Eu μg/g < 0.002 ± 0.001 < 0.002 ± 0.001 < 0.002 ± 0.001 < 0.002 ± 0.001 0.24 ± 0.01 0.2

Fe μg/g 65 ± 18 120 ± 10 26 ± 12 40 ± 6 87 ± 44 83 ± 5

Gd μg/g < 0.004 ± 0.001 < 0.004 ± 0.003 < 0.004 ± 0.002 < 0.004 ± 0.001 2.9 ± 0.1 3

Hg ng/g 23 ± 0 13 ± 0 27 ± 1 19 ± 1 33 ± 1 44 ± 4

Ho μg/g 0.0017 ± 0.0009 0.002 ± 0.001 < 0.0009 ± 0.0008< 0.0009 ± 0.0002 0.27 ± 0 ND

La μg/g 0.009 ± 0.0002 0.039 ± 0.009 0.02 ± 0.008 0.021 ± 0.005 20 ± 0 20

Li μg/g 1.2 ± 0.1 1.1 ± 0.2 2.5 ± 0.4 3.2 ± 0.2 < 0.1 ± 0.1 ND

Lu μg/g < 0.001 ± 0.001 0.0014 ± 0.0013 < 0.001 ± 0 < 0.001 ± 0.001 0.021 ± 0.001 ND

Mg wt% 0.14 ± 0.01 0.13 ± 0.02 0.11 ± 0.02 0.13 ± 0.02 0.28 ± 0.01 0.27 ± 0.01

Mn μg/g 250 ± 20 53 ± 8 230 ± 10 100 ± 10 52 ± 3 54 ± 3

Mo μg/g < 0.2 ± 0.4 0.6 ± 0.3 0.6 ± 0.3 0.4 ± 0.1 < 0.2 ± 0.1 0.094 ± 0.013

Na wt% 0.28 ± 0.03 0.38 ± 0.07 0.52 ± 0.1 0.8 ± 0.04 0.005 ± 0.003 0.0024 ± 0.0001

Nd μg/g 0.009 ± 0.003 0.039 ± 0.009 0.017 ± 0.002 0.026 ± 0.004 16 ± 0 17

Ni μg/g < 0.05 ± 0.1 < 0.05 ± 0.24 < 0.05 ± 0.11 < 0.05 ± 0.05 < 0.05 ± 0.14 0.91 ± 0.12

P μg/g 3200 ± 200 2000 ± 300 2000 ± 400 1500 ± 300 1500 ± 100 1600 ± 100

Pb μg/g 0.03 ± 0.04 0.14 ± 0.06 0.02 ± 0.01 0.04 ± 0.05 0.4 ± 0.04 0.47 ± 0.02

Pr μg/g 0.0013 ± 0.001 0.012 ± 0.003 0.0024 ± 0.0029 0.0049 ± 0.0011 4.1 ± 0.2 ND

Rb μg/g 7.6 ± 0.5 9.6 ± 1.5 6.1 ± 1.2 4.7 ± 0.7 9.6 ± 0.4 10.2 ± 1.5

Re μg/g < 0.002 ± 0 < 0.002 ± 0.001 < 0.002 ± 0.001 < 0.002 ± 0.002 < 0.002 ± 0 ND

S wt% 0.39 ± 0.03 0.34 ± 0.02 0.46 ± 0.06 0.7 ± 0.03 0.2 ± 0.03 0.18

Sb μg/g < 0.02 ± 0.03 < 0.02 ± 0.01 < 0.02 ± 0.03 < 0.02 ± 0.01 < 0.02 ± 0.01 0.013

Sc μg/g < 0.4 ± 0.1 < 0.4 ± 0.2 < 0.4 ± 0.2 < 0.4 ± 0.3 < 0.4 ± 0.3 0.03

Se μg/g < 0.7 ± 0.3 < 0.7 ± 0.7 < 0.7 ± 0.3 < 0.7 ± 0.6 0.9 ± 0.4 0.05 ± 0.01

Si wt% 0.19 ± 0.04 0.16 ± 0.03 0.25 ± 0.01 0.087 ± 0.008 0.033 ± 0.003 ND

Sm μg/g < 0.006 ± 0.002 0.012 ± 0.004 0.007 ± 0.006 0.008 ± 0.001 2.7 ± 0.1 3

Sr μg/g 51 ± 4 56 ± 9 59 ± 12 45 ± 6 24 ± 1 25 ± 2

Ta μg/g < 0.010 ± 0.006 < 0.010 ± 0.002 < 0.010 ± 0.007 < 0.010 ± 0.003 < 0.010 ± 0.007 ND

Tb μg/g < 0.001 ± 0.001 < 0.001 ± 0.001 < 0.001 ± 0.001 < 0.001 ± 0.001 0.36 ± 0 0.4

Te μg/g < 0.06 ± 0.02 < 0.06 ± 0.03 < 0.06 ± 0 < 0.06 ± 0.02 < 0.06 ± 0.03 ND

Th μg/g < 0.02 ± 0.01 < 0.02 ± 0.01 < 0.02 ± 0.02 < 0.02 ± 0.01 < 0.02 ± 0 0.03

Tl μg/g < 0.02 ± 0.04 < 0.02 ± 0.02 < 0.02 ± 0.01 < 0.02 ± 0.04 < 0.02 ± 0.01 ND

Tm μg/g < 0.0008 ± 0.0001< 0.0008 ± 0.0014 < 0.0008 ± 0.0004< 0.0008 ± 0.0003 0.053 ± 0.001 ND

U μg/g 0.01 ± 0.006 0.057 ± 0.023 0.014 ± 0.006 0.024 ± 0.025 0.007 ± 0.006 0.006

V μg/g < 0.7 ± 0.3 < 0.6 ± 0.2 < 0.7 ± 0.2 < 0.7 ± 0.5 < 0.7 ± 0.6 0.26 ± 0.03

Y μg/g 0.068 ± 0.007 0.1 ± 0.03 0.12 ± 0.02 0.077 ± 0.014 9.4 ± 0.1 ND

Yb μg/g < 0.003 ± 0.001 0.004 ± 0.003 < 0.003 ± 0.001 < 0.003 ± 0.003 0.2 ± 0.02 0.3

Zn μg/g 16 ± 5 25 ± 7 9.9 ± 2.9 8.2 ± 2.1 11 ± 1 12.5 ± 0.3

Zr μg/g 0.67 ± 0.04 0.92 ± 0.27 1.5 ± 0.1 0.7 ± 0.04 0.06 ± 0.01 ND

76
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

0

10

20

30

40

50 A

ALUMINUM CONCENTRATION, 

in micrograms per gram

Schoenoplectus tabernaemontani Schoenoplectus americanus

Inlet Outlet

0.0

0.5

1.0

1.5 f

ZINC CONCENTRATION,

in micrograms per gram

Inlet Outlet

0.00

0.05

0.10

0.15

0.20

e

LEAD CONCENTRATION,

in micrograms per gram

Inlet Outlet

0

1

2

3

4

5

d

COPPER CONCENTRATION,

in micrograms per gram

Inlet Outlet

0.0

0.1

0.2

0.3

0.4

0.5

0.6

c

CADMIUM CONCENTRATION,

in micrograms per gram

Inlet Outlet

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

b

ARSENIC CONCENTRATION,

in micrograms per gram

Inlet Outlet

Figure 4-6. Plots of (a) aluminum, (b) arsenic, (c) cadmium, (d) copper, (e) lead, and (f) zinc 

concentrations (dry-weight basis) for softstem (Schoenoplectus tabernaemontani) and Olney’s 

(Schoenoplectus americanus) bulrush samples collected at the inlet and outlet of the Cobble 2 wetland, 

June 23, 1998. 

77
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Ag As B Ba Be Cd Co Cr Cu Fe Li MgMnMo Ni Pb Rb Sb Se Sr Th Tl U V Y Zn Zr

10-3

10-2

10-1

100

101

102

103

104

CONCENTRATION,

in micrograms per gram (dry weight)

ELEMENT

Gambusia

Tilapia

Figure 4-7. Plot of 27 selected trace-element concentrations for Gambusia and Tilapia whole-body tissue 

collected at the Hayfield 2 wetland, July 23, 1998. 

FISH TISSUE

Elemental composition data for two species of fish, Gambusia and Tilapia, collected 

from the H2 wetland on July 23, 1998, are listed in table 4-10. For Gambusia, whole-body data 

are reported in micrograms per gram (μg/g) on a dry-weight basis. Tilapia specimens were 

analyzed for both whole-body and dissected parts, including liver and filet tissue (table 2-15). 

Figure 4-7 shows a plot of 27 selected elements comparing the whole-body trace element 

composition of Gambusia and Tilapia. This figure demonstrates a high degree of similarity in 

composition between the two fish species. 

 Table 4-11 lists elemental data for Gambusia whole-body, and Tilapia filet and liver 

tissue collected from the Hayfield and Cobble wetlands, February 14, 2000. Data are reported in 

μg/g on a dry-weight basis. Replicate samples of both filet and liver tissue are listed as are data 

for NRC Dogfish Muscle Standard, DORM-1, and Dogfish Liver Standard, DOLT-1, SRM. 

Figure 4-8 shows plots for selected elements comparing concentrations in whole-body Gambusia

and Tilapia filet and liver tissue. Replicate samples are designated to demonstrate variability 

between individual organisms. 

78
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 4-10. Trace-element composition data for Gambusia whole-body and Tilapia whole-body, filet, 

liver, and other tissue samples collected from the Hayfield 2 wetland, July 23, 1998. [Values reported on 

a dry-weight basis; μg/g, microgram per gram; wt%, weight percent] 

Element 

Concentration 

Unit 

Gambusia

whole-body 1 

Tilapia

whole-body 1 

Tilapia

whole-body 2 

Tilapia

filet 1 

Tilapia

filet 2 

Al μg/g 530 ± 20 960 ± 10 680 ± 0 3 ± 0 27 ± 1

As μg/g 0.45 ± 0.01 0.67 ± 0.01 0.45 ± 0 0.08 ± 0 0.19 ± 0.01

B μg/g 1.2 ± 0.1 1.2 ± 0.1 1 ± 0 0.9 ± 0 0.5 ± 0

Ba μg/g 27 ± 0 21 ± 0 12 ± 0 0.2 ± 0 1 ± 0

Be μg/g 0.025 ± 0.002 0.039 ± 0.004 0.031 ± 0.002 < 0.002 ± 0.001 0.004 ± 0

Bi μg/g 0.031 ± 0 0.13 ± 0 0.18 ± 0.01 0.006 ± 0.001 0.023 ± 0.001

Ca wt% 3.7 ± 0 6.3 ± 0 4.5 ± 0.1 0.11 ± 0 0.54 ± 0

Cd μg/g 0.015 ± 0.001 0.016 ± 0.001 0.011 ± 0.001 0.0006 ± 0.0004 < 0.0008 ± 0.0004

Ce μg/g 1.5 ± 0 2.4 ± 0 1.8 ± 0 0.008 ± 0 0.072 ± 0

Co μg/g 0.44 ± 0 0.59 ± 0.02 0.42 ± 0.01 0.02 ± 0 0.07 ± 0

Cr μg/g 1.1 ± 0 2.2 ± 0 1.6 ± 0 0.2 ± 0.01 0.19 ± 0.11

Cs μg/g 0.18 ± 0.01 0.29 ± 0.01 0.23 ± 0 0.11 ± 0.01 0.08 ± 0.02

Cu μg/g 3.9 ± 0 3.7 ± 0 3.5 ± 0 0.7 ± 0 0.8 ± 0

Dy μg/g 0.091 ± 0.002 0.14 ± 0 0.1 ± 0 0.0005 ± 0.0001 0.0043 ± 0.0002

Er μg/g 0.036 ± 0 0.059 ± 0 0.043 ± 0 0.0003 ± 0.0001 0.002 ± 0.0003

Eu μg/g 0.027 ± 0 0.043 ± 0.001 0.031 ± 0.002 0.0001 ± 0 0.0012 ± 0

Fe μg/g 720 ± 40 1200 ± 100 930 ± 90 17 ± 2 61 ± 3

Gd μg/g 0.1 ± 0 0.16 ± 0 0.12 ± 0 0.0007 ± 0.0001 0.0054 ± 0

Ho μg/g 0.014 ± 0 0.022 ± 0.001 0.016 ± 0 0.0001 ± 0 0.0007 ± 0.0001

La μg/g 0.69 ± 0 1 ± 0 0.77 ± 0 0.004 ± 0 0.035 ± 0.001

Li μg/g 1.3 ± 0 2.2 ± 0 1.7 ± 0 0.05 ± 0.01 0.18 ± 0.02

Lu μg/g 0.005 ± 0.0001 0.0079 ± 0.0005 0.0059 ± 0 0.0001 ± 0 0.0002 ± 0

Mg wt% 0.18 ± 0 0.21 ± 0.01 0.16 ± 0 0.14 ± 0 0.16 ± 0

Mn μg/g 27 ± 0 21 ± 1 20 ± 1 0.6 ± 0 1.9 ± 0.1

Mo μg/g 0.34 ± 0 0.68 ± 0.02 0.57 ± 0.02 0.07 ± 0.02 0.09 ± 0.01

Na wt% 0.36 ± 0 0.57 ± 0.02 0.42 ± 0.02 0.27 ± 0 0.4 ± 0.01

Nd μg/g 0.67 ± 0.01 1 ± 0 0.76 ± 0 0.003 ± 0 0.033 ± 0

Ni μg/g 1.2 ± 0 2.2 ± 0 1.5 ± 0.1 0.09 ± 0.02 0.58 ± 0

P wt% 1.8 ± 0 3.1 ± 0 2.2 ± 0.1 0.76 ± 0.03 0.91 ± 0.01

Pb μg/g 0.4 ± 0 0.76 ± 0 0.54 ± 0.01 0.008 ± 0 0.028 ± 0

Pr μg/g 0.18 ± 0 0.28 ± 0.01 0.21 ± 0.01 0.001 ± 0 0.009 ± 0

Rb μg/g 8 ± 0.1 6.7 ± 0 5.8 ± 0 11 ± 0 10 ± 0

Re μg/g 0.001 ± 0 < 0.001 ± 0 < 0.001 ± 0.001 < 0.001 ± 0 0.005 ± 0.001

S wt% 1.6 ± 0 1.4 ± 0.1 1.1 ± 0 1.6 ± 0 2.2 ± 0.1

Sb μg/g 0.018 ± 0.001 0.039 ± 0.001 0.031 ± 0.001 0.002 ± 0 0.004 ± 0

Se μg/g 2 ± 0 3 ± 0 2.3 ± 0.1 3 ± 0.1 3.8 ± 0

Si wt% 0.23 ± 0 0.23 ± 0 0.19 ± 0 0.03 ± 0 0.06 ± 0

Sm μg/g 0.13 ± 0 0.2 ± 0 0.15 ± 0 0.0008 ± 0.0002 0.0061 ± 0.0002

Sr μg/g 130 ± 0 300 ± 0 190 ± 0 3.7 ± 0.1 21 ± 0

Tb μg/g 0.012 ± 0 0.019 ± 0 0.014 ± 0 0.0001 ± 0 0.0007 ± 0.0001

Te μg/g < 0.02 ± 0.01 < 0.02 ± 0.01 < 0.01 ± 0.01 < 0.02 ± 0.01 < 0.03 ± 0

Th μg/g 0.13 ± 0 0.23 ± 0 0.16 ± 0 0.001 ± 0 0.007 ± 0.001

Tl μg/g 0.0054 ± 0.0002 0.0086 ± 0.0001 0.0068 ± 0.0001 < 0.0002 ± 0.0001 0.0006 ± 0.0003

Tm μg/g 0.0067 ± 0.0002 0.011 ± 0 0.0079 ± 0 < 0.0001 ± 0 0.0003 ± 0.0001

U μg/g 0.045 ± 0 0.35 ± 0 0.18 ± 0.01 0.002 ± 0 0.012 ± 0

V μg/g 1.4 ± 0 3 ± 0 2.1 ± 0 < 0.005 ± 0.001 0.08 ± 0.03

Y μg/g 0.41 ± 0 0.65 ± 0.02 0.47 ± 0.01 0.002 ± 0 0.02 ± 0

Yb μg/g 0.039 ± 0 0.062 ± 0.002 0.044 ± 0.001 0.0003 ± 0.0001 0.0019 ± 0.0002

Zn μg/g 110 ± 0 140 ± 0 81 ± 0 18 ± 0 41 ± 1

Zr μg/g 0.85 ± 0 1.5 ± 0.1 1.2 ± 0 0.009 ± 0 0.057 ± 0.001

79
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 4-10. Continued.

Element 

Concentration 

Unit 

Tilapia 

liver 1 

Tilapia

liver 2 

Tilapia 

other 1 

Tilapia 

other 2 

Al μg/g 81 ± 0 170 ± 0 280 ± 0 1100 ± 0

As μg/g 0.38 ± 0 0.58 ± 0 0.3 ± 0 0.78 ± 0.01

B μg/g 1.6 ± 0.1 4.1 ± 0 1.7 ± 0.1 1.6 ± 0

Ba μg/g 1.2 ± 0 2.7 ± 0 12 ± 0 21 ± 0

Be μg/g 0.004 ± 0.003 < 0.005 ± 0.009 0.014 ± 0 0.053 ± 0.002

Bi μg/g 0.32 ± 0 0.26 ± 0 0.082 ± 0 0.38 ± 0

Ca wt% 0.15 ± 0.03 0.37 ± 0.24 5.9 ± 0 5.2 ± 0

Cd μg/g 0.046 ± 0.001 0.023 ± 0 0.0091 ± 0.0006 0.018 ± 0.001

Ce μg/g 0.23 ± 0 0.47 ± 0.01 0.71 ± 0 3 ± 0.1

Co μg/g 1.4 ± 0 0.79 ± 0.02 0.17 ± 0 0.75 ± 0.01

Cr μg/g 0.39 ± 0.05 1.8 ± 0 0.82 ± 0.07 3 ± 0

Cs μg/g 0.05 ± 0.01 0.11 ± 0.01 0.14 ± 0 0.37 ± 0.01

Cu μg/g 216 ± 1 78 ± 1 2.6 ± 0 4.4 ± 0.1

Dy μg/g 0.01 ± 0 0.021 ± 0 0.042 ± 0.001 0.17 ± 0

Er μg/g 0.0045 ± 0.0005 0.0081 ± 0.0007 0.017 ± 0 0.072 ± 0.001

Eu μg/g 0.0034 ± 0.0004 0.0068 ± 0.0002 0.013 ± 0 0.053 ± 0.001

Fe μg/g 1700 ± 100 2600 ± 100 550 ± 30 1600 ± 100

Gd μg/g 0.014 ± 0 0.028 ± 0.004 0.062 ± 0.022 0.2 ± 0

Ho μg/g 0.0015 ± 0.0001 0.0034 ± 0.0001 0.0067 ± 0.0001 0.026 ± 0

La μg/g 0.12 ± 0 0.21 ± 0 0.32 ± 0.01 1.3 ± 0

Li μg/g 0.31 ± 0 0.57 ± 0.02 0.92 ± 0.02 2.7 ± 0.1

Lu μg/g 0.0005 ± 0 0.0012 ± 0.0002 0.0026 ± 0.0001 0.0097 ± 0.0002

Mg wt% 0.08 ± 0 0.12 ± 0.01 0.18 ± 0 0.23 ± 0

Mn μg/g 10 ± 0 19 ± 0 16 ± 1 38 ± 2

Mo μg/g 27 ± 0 12 ± 0 0.37 ± 0 0.79 ± 0.02

Na wt% 0.83 ± 0 0.79 ± 0 0.54 ± 0 0.53 ± 0.02

Nd μg/g 0.095 ± 0.002 0.19 ± 0 0.31 ± 0.01 1.3 ± 0

Ni μg/g 2.1 ± 0 2.7 ± 0 0.65 ± 0.08 2.5 ± 0.1

P wt% 0.91 ± 0.01 0.94 ± 0.15 3 ± 0 2.7 ± 0

Pb μg/g 0.16 ± 0 0.24 ± 0.01 0.39 ± 0 0.93 ± 0

Pr μg/g 0.025 ± 0 0.05 ± 0 0.083 ± 0 0.35 ± 0

Rb μg/g 6.6 ± 0 5.5 ± 0 7.9 ± 0 8.7 ± 0.3

Re μg/g 0.003 ± 0 < 0.004 ± 0.001 0.003 ± 0.005 0.003 ± 0.003

S wt% 1.7 ± 0 1.5 ± 0 1.5 ± 0.1 1.5 ± 0.1

Sb μg/g 0.058 ± 0.001 0.036 ± 0.001 0.022 ± 0.002 0.047 ± 0.002

Se μg/g 30 ± 0 15 ± 0 3.3 ± 0 3.3 ± 0.1

Si wt% 0.6 ± 0 0.89 ± 0 0.47 ± 0 0.29 ± 0

Sm μg/g 0.017 ± 0 0.035 ± 0.001 0.058 ± 0.002 0.25 ± 0

Sr μg/g 8 ± 0.2 18 ± 0 270 ± 0 230 ± 10

Tb μg/g 0.0014 ± 0.0001 0.003 ± 0.0002 0.0056 ± 0.0001 0.023 ± 0

Te μg/g 0.06 ± 0.01 < 0.06 ± 0.04 < 0.02 ± 0 < 0.01 ± 0.01

Th μg/g 0.011 ± 0 0.013 ± 0.001 0.061 ± 0 0.26 ± 0

Tl μg/g 0.0027 ± 0.0001 0.003 ± 0.0025 0.0034 ± 0.0008 0.012 ± 0

Tm μg/g 0.0007 ± 0 0.0015 ± 0 0.0032 ± 0.0002 0.013 ± 0

U μg/g 0.082 ± 0 0.1 ± 0 0.12 ± 0 0.32 ± 0.01

V μg/g 0.72 ± 0.01 0.52 ± 0 1.5 ± 0 3.3 ± 0

Y μg/g 0.046 ± 0.001 0.1 ± 0 0.2 ± 0 0.79 ± 0.01

Yb μg/g 0.004 ± 0.0001 0.0098 ± 0.0001 0.019 ± 0.001 0.075 ± 0.002

Zn μg/g 110 ± 0 110 ± 0 86 ± 0 110 ± 0

Zr μg/g 0.04 ± 0.003 0.004 ± 0.004 0.54 ± 0.01 2.1 ± 0

80
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 4-11. Trace-element composition data for Gambusia whole-body tissue collected from the Cobble 

2 wetland, and Tilapia filet and liver tissue collected from the Hayfield 1 wetland, February 14, 2000. 

[Values reported on a dry-weight basis; μg/g, microgram per gram; ng/g, nanogram per gram; wt%, 

weight percent; analysis of Dogfish Muscle Standard, DORM-1, and Dogfish Liver Standard, DOLT-1, 

are listed with certified values (Taylor, 2001); ND, not determined] 

Element 

Concentration 

Unit 

Gambusia

whole-body 

Tilapia

filet 1

Tilapia

filet 3

Tilapia

filet 4

Tilapia

filet 5

Tilapia

filet 6

Al μg/g 22 ± 5 < 0.8 ± 1.6 < 1 ± 1 < 0.9 ± 1 < 0.3 ± 1.1 < 0.9 ± 1.7

As μg/g 0.46 ± 0.11 0.3 ± 0.22 0.49 ± 0.24 0.46 ± 0.2 0.12 ± 0.06 0.4 ± 0.14

B μg/g < 9 ± 6 < 9 ± 3 < 10 ± 0 < 10 ± 11 6 ± 2 < 10 ± 3

Ba μg/g 9.4 ± 0 < 0.06 ± 0.07 < 0.09 ± 0.01 0.76 ± 0.07 0.04 ± 0.02 0.4 ± 0.08

Be μg/g < 0.3 ± 0.1 < 0.3 ± 0.1 < 0.4 ± 0.3 < 0.3 ± 0.3 < 0.09 ± 0.05 < 0.3 ± 0.2

Bi μg/g < 0.005 ± 0.008 < 0.005 ± 0.009 < 0.007 ± 0.015 < 0.006 ± 0.01 < 0.002 ± 0.002 0.024 ± 0.034

Ca wt% 5.3 ± 0.2 0.07 ± 0.019 0.12 ± 0.01 1 ± 0.1 0.022 ± 0.002 1 ± 0.1

Cd μg/g < 0.07 ± 0.06 < 0.07 ± 0 < 0.09 ± 0.1 < 0.07 ± 0.11 < 0.02 ± 0.02 < 0.07 ± 0.07

Ce μg/g 0.092 ± 0.004 < 0.003 ± 0.007 < 0.004 ± 0.005 < 0.003 ± 0.005 0.004 ± 0.002 0.012 ± 0.008

Co μg/g < 0.05 ± 0.06 < 0.05 ± 0.02 < 0.07 ± 0.08 < 0.06 ± 0.06 < 0.02 ± 0.01 < 0.06 ± 0.02

Cr μg/g < 2 ± 1 < 2 ± 0 4 ± 4 < 2 ± 0 < 0.7 ± 0.3 < 2 ± 1

Cs μg/g < 1 ± 0 < 1 ± 1 < 2 ± 0 < 2 ± 0 < 0.5 ± 0 < 2 ± 0

Cu μg/g 8.3 ± 0.5 3.2 ± 1 4.3 ± 0.5 3.6 ± 1.8 0.5 ± 0.1 2.2 ± 0.3

Dy μg/g 0.007 ± 0.008 < 0.007 ± 0.003 < 0.010 ± 0.006 < 0.008 ± 0.006 < 0.002 ± 0.002 < 0.008 ± 0.002

Er μg/g < 0.01 ± 0.01 < 0.01 ± 0 < 0.02 ± 0.01 < 0.01 ± 0.01 < 0.004 ± 0.002 < 0.01 ± 0

Eu μg/g < 0.003 ± 0 < 0.003 ± 0.001 < 0.005 ± 0.002 < 0.004 ± 0.003 < 0.003 ± 0.001 < 0.004 ± 0.003

Fe μg/g 180 ± 20 < 5 ± 3 13 ± 3 19 ± 17 3 ± 1 13 ± 1

Gd μg/g < 0.009 ± 0.008 < 0.007 ± 0.003 < 0.01 ± 0 < 0.009 ± 0.003 < 0.003 ± 0.001 < 0.009 ± 0.004

Hg ng/g 64 ± 0 8 ± 1 8 ± 3 15 ± 2 6 ± 2 14 ± 3

Ho μg/g < 0.002 ± 0.001 < 0.002 ± 0.001 < 0.002 ± 0.002 < 0.002 ± 0.002 < 0.0006 ± 0.0006 < 0.002 ± 0

K wt% 1.2 ± 0.1 1.3 ± 0.1 1.6 ± 0.1 1.5 ± 0.2 0.35 ± 0.03 1.5 ± 0.1

La μg/g 0.045 ± 0.001 < 0.003 ± 0.003 < 0.004 ± 0.001 < 0.003 ± 0.001 0.002 ± 0.001 0.007 ± 0.002

Li μg/g 0.3 ± 0 0.2 ± 0.2 < 0.3 ± 0.3 0.6 ± 0.1 0.1 ± 0.1 < 0.2 ± 0

Lu μg/g < 0.002 ± 0 < 0.002 ± 0.001 < 0.003 ± 0.001 < 0.002 ± 0.001 < 0.0007 ± 0.0001 < 0.002 ± 0.001

Mg wt% 0.19 ± 0.01 0.073 ± 0.02 0.13 ± 0 0.13 ± 0.01 0.019 ± 0.002 0.12 ± 0.01

Mn μg/g 18 ± 1 0.14 ± 0.1 0.91 ± 1.06 1.1 ± 0.7 0.18 ± 0.07 1.7 ± 1.2

Mo μg/g < 0.1 ± 0.1 < 0.1 ± 0.1 < 0.2 ± 0.4 < 0.1 ± 0.1 < 0.04 ± 0.22 < 0.1 ± 0.2

Na wt% 0.37 ± 0.02 0.36 ± 0.1 0.51 ± 0.01 0.44 ± 0.03 0.13 ± 0.01 0.54 ± 0.05

Nd μg/g 0.038 ± 0.011 < 0.01 ± 0 < 0.02 ± 0.01 < 0.01 ± 0.01 < 0.004 ± 0.002 < 0.01 ± 0.01

Ni μg/g < 0.2 ± 0.4 1.1 ± 0.2 < 0.3 ± 0.3 0.3 ± 0 < 0.06 ± 0.05 < 0.2 ± 0.3

P wt% 2.91 ± 0.06 0.53 ± 0.11 0.76 ± 0.06 0.96 ± 0.05 0.14 ± 0.03 0.94 ± 0.04

Pb μg/g 0.05 ± 0.15 < 0.04 ± 0.01 < 0.05 ± 0.15 < 0.04 ± 0 < 0.01 ± 0 < 0.04 ± 0.06

Pd μg/g 0.014 ± 0.003 < 0.01 ± 0 < 0.02 ± 0.01 0.015 ± 0.015 < 0.004 ± 0.003 < 0.01 ± 0.01

Pr μg/g 0.013 ± 0.002 0.003 ± 0.001 < 0.004 ± 0.003 < 0.003 ± 0 < 0.0009 ± 0.0008 < 0.003 ± 0.002

Rb μg/g 11 ± 1 6.3 ± 1.7 9 ± 0.2 7.9 ± 0.3 1.8 ± 0.2 9.5 ± 0.9

Re μg/g < 0.006 ± 0.003 < 0.006 ± 0.002 < 0.008 ± 0.003 < 0.006 ± 0.002 < 0.002 ± 0.001 < 0.006 ± 0.002

S wt% 1.17 ± 0.09 0.82 ± 0.08 1.3 ± 0.05 1.23 ± 0.16 0.23 ± 0.02 1.18 ± 0.16

Sb μg/g < 0.04 ± 0.02 < 0.04 ± 0.05 < 0.06 ± 0.02 < 0.05 ± 0.01 < 0.01 ± 0.01 < 0.05 ± 0.01

Se μg/g 5.2 ± 0.4 3.9 ± 2 6.1 ± 1.4 2.1 ± 0.1 1 ± 0.2 5.2 ± 1.2

Si wt% < 0.02 ± 0.02 < 0.02 ± 0.01 < 0.04 ± 0.02 < 0.03 ± 0 < 0.009 ± 0.002 < 0.03 ± 0.02

Sm μg/g 0.011 ± 0.003 < 0.007 ± 0.003 < 0.01 ± 0.01 < 0.008 ± 0.012 < 0.003 ± 0.001 < 0.008 ± 0.001

Sr μg/g 170 ± 10 1.9 ± 0.5 3.5 ± 0.6 37 ± 2 0.5 ± 0.1 40 ± 3

Ta μg/g 0.019 ± 0.015 < 0.01 ± 0 0.027 ± 0.008 0.041 ± 0.003 0.013 ± 0.002 0.016 ± 0.004

Tb μg/g < 0.002 ± 0 < 0.002 ± 0.001 < 0.003 ± 0.001 0.002 ± 0.003 < 0.0007 ± 0.0002 < 0.002 ± 0.001

Te μg/g < 0.1 ± 0 < 0.1 ± 0.1 < 0.2 ± 0.2 < 0.1 ± 0.1 < 0.04 ± 0.02 < 0.1 ± 0

Th μg/g < 0.008 ± 0.015 < 0.008 ± 0.009 < 0.01 ± 0 < 0.009 ± 0.007 < 0.003 ± 0.001 < 0.009 ± 0.012

Tl μg/g < 0.06 ± 0.01 < 0.06 ± 0.14 < 0.08 ± 0.02 < 0.07 ± 0.07 < 0.02 ± 0.05 < 0.07 ± 0.06

Tm μg/g < 0.002 ± 0.001 < 0.002 ± 0.002 < 0.003 ± 0.001 < 0.002 ± 0 < 0.0007 ± 0.0003 < 0.002 ± 0.001

U μg/g 0.035 ± 0.011 < 0.006 ± 0.01 < 0.009 ± 0.003 0.009 ± 0.001 < 0.002 ± 0.003 0.023 ± 0.003

V μg/g < 0.8 ± 0.1 < 0.8 ± 0.8 < 1 ± 1 < 0.9 ± 0.9 < 0.3 ± 0.1 1.1 ± 1.5

Y μg/g 0.028 ± 0.008 < 0.003 ± 0 0.008 ± 0.003 0.011 ± 0.009 0.001 ± 0.002 0.01 ± 0.003

Yb μg/g < 0.008 ± 0.001 < 0.008 ± 0.003 < 0.01 ± 0 < 0.008 ± 0.008 < 0.003 ± 0 < 0.008 ± 0.001

Zn μg/g 180 ± 0 27 ± 6 42 ± 4 57 ± 10 8 ± 1 49 ± 8

Zr μg/g 0.13 ± 0.02 0.05 ± 0.01 0.07 ± 0.01 0.07 ± 0 0.04 ± 0.01 0.08 ± 0.01

81
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Table 4-11. Continued.

Element 

Concentration 

Unit 

Tilapia

filet 8

Tilapia

filet 10

Tilapia

liver 1 

Tilapia

liver 5 

Tilapia

liver 6 

Tilapia

liver 7 

Al μg/g < 1.0 ± 1.3 < 4 ± 3 42 ± 3 200 ± 50 96 ± 4 13000 ± 1000 

As μg/g 0.56 ± 0.28 1.8 ± 1.5 0.23 ± 0.05 0.37 ± 0.13 1.7 ± 0.3 3.8 ± 1.4 

B μg/g < 10 ± 6 < 40 ± 70 < 6 ± 1 < 7 ± 1 < 20 ± 20 82 ± 45 

Ba μg/g < 0.07 ± 0.07 < 0.3 ± 0.1 0.85 ± 0.08 9.3 ± 2.4 2.2 ± 0 140 ± 10 

Be μg/g < 0.3 ± 0.3 < 1 ± 1 < 0.2 ± 0.1 < 0.2 ± 0.2 < 0.6 ± 0.6 1.8 ± 0.8 

Bi μg/g < 0.006 ± 0.009 < 0.03 ± 0.01 0.046 ± 0.004 0.22 ± 0.05 0.24 ± 0.02 1.7 ± 0.3 

Ca wt% 0.1 ± 0.02 0.35 ± 0.06 0.43 ± 0.01 0.13 ± 0.03 0.8 ± 0.02 0.56 ± 0.09 

Cd μg/g < 0.08 ± 0.06 < 0.3 ± 0.3 < 0.05 ± 0.02 < 0.05 ± 0.06 < 0.2 ± 0.1 < 0.4 ± 0.3 

Ce μg/g 0.005 ± 0.004 < 0.02 ± 0.02 0.06 ± 0.007 0.39 ± 0.11 0.33 ± 0.05 24 ± 1 

Co μg/g < 0.06 ± 0.02 < 0.3 ± 0.2 0.07 ± 0.02 0.19 ± 0.07 0.52 ± 0.06 4.7 ± 0.7 

Cr μg/g 3 ± 2 < 10 ± 0 < 1 ± 1 < 2 ± 1 < 5 ± 4 30 ± 12 

Cs μg/g < 2 ± 1 < 7 ± 2 < 1 ± 0 < 1 ± 1 < 4 ± 0 19 ± 2 

Cu μg/g 2.5 ± 0.6 18 ± 2 45 ± 0 51 ± 13 280 ± 30 47 ± 3 

Dy μg/g < 0.008 ± 0.005 < 0.04 ± 0.02 < 0.005 ± 0.001 0.007 ± 0.002 < 0.02 ± 0 1.2 ± 0 

Er μg/g < 0.01 ± 0.01 < 0.06 ± 0.02 < 0.008 ± 0.004 < 0.008 ± 0.004 < 0.03 ± 0.02 0.057 ± 0.02 

Eu μg/g < 0.004 ± 0.002 < 0.02 ± 0.02 < 0.002 ± 0.001 0.004 ± 0.002 < 0.008 ± 0.005 0.34 ± 0.01 

Fe μg/g 19 ± 5 31 ± 14 310 ± 10 930 ± 40 1600 ± 0 14000 ± 1000 

Gd μg/g < 0.01 ± 0.009 < 0.04 ± 0.04 < 0.006 ± 0.002 0.015 ± 0.005 0.021 ± 0.02 1.4 ± 0 

Hg ng/g 15 ± 3 8 ± 2 8 ± 4 14 ± 9 63 ± 6 54 ± 16 

Ho μg/g 0.003 ± 0.002 < 0.008 ± 0.005 < 0.001 ± 0.001 0.003 ± 0.001 0.005 ± 0.002 0.24 ± 0 

K wt% 1.9 ± 0 5 ± 0.2 0.28 ± 0.02 0.28 ± 0.08 1.7 ± 0.2 1.1 ± 0.3 

La μg/g 0.006 ± 0.004 < 0.01 ± 0.01 0.024 ± 0.003 0.15 ± 0.04 0.16 ± 0.01 11 ± 1 

Li μg/g 0.3 ± 0.2 < 1.0 ± 0.6 < 0.1 ± 0 0.3 ± 0.1 0.5 ± 0.1 17 ± 2 

Lu μg/g < 0.002 ± 0.001 < 0.010 ± 0.009 < 0.001 ± 0.001 < 0.001 ± 0.001 < 0.005 ± 0.003 0.078 ± 0.012 

Mg wt% 0.11 ± 0.01 0.29 ± 0.03 0.047 ± 0.002 0.06 ± 0.015 0.24 ± 0.03 0.52 ± 0.05 

Mn μg/g 1.3 ± 1.3 2.5 ± 5.3 1.6 ± 0 6.2 ± 1.5 6.4 ± 1.3 110 ± 10 

Mo μg/g < 0.1 ± 0.2 < 0.6 ± 1.4 4.2 ± 0.1 2.8 ± 0.5 26 ± 0 4.2 ± 1.5 

Na wt% 0.57 ± 0.08 1.6 ± 0.1 0.21 ± 0.01 0.21 ± 0.05 1.2 ± 0.1 0.43 ± 0.05 

Nd μg/g 0.014 ± 0.007 < 0.06 ± 0.03 0.021 ± 0.003 0.11 ± 0.03 0.1 ± 0.02 9.7 ± 1 

Ni μg/g 0.3 ± 0 < 0.9 ± 0.2 0.4 ± 0.1 0.8 ± 0 1.8 ± 0.4 18 ± 1 

P wt% 0.83 ± 0.12 2.08 ± 0.02 0.34 ± 0.08 0.2 ± 0.06 1.24 ± 0.24 0.61 ± 0.07 

Pb μg/g 0.08 ± 0.15 < 0.2 ± 0.7 0.03 ± 0.02 0.39 ± 0.12 0.44 ± 0.07 10 ± 1 

Pd μg/g 0.017 ± 0.024 < 0.06 ± 0.04 0.009 ± 0.002 0.027 ± 0.007 0.033 ± 0.028 0.17 ± 0.06 

Pr μg/g 0.006 ± 0.003 0.019 ± 0.014 0.006 ± 0.002 0.032 ± 0.006 0.037 ± 0.016 2.7 ± 0.1 

Rb μg/g 10 ± 0 25 ± 3 1.8 ± 0.1 1.7 ± 0.4 10 ± 1 25 ± 2 

Re μg/g < 0.007 ± 0.001 < 0.03 ± 0.01 < 0.004 ± 0 < 0.004 ± 0.001 < 0.01 ± 0.01 < 0.03 ± 0.01 

S wt% 1.41 ± 0.07 3.54 ± 0.42 0.2 ± 0 0.18 ± 0.03 1.2 ± 0.11 0.55 ± 0.1 

Sb μg/g < 0.05 ± 0.02 < 0.2 ± 0.2 < 0.03 ± 0.01 < 0.03 ± 0.03 < 0.1 ± 0 < 0.3 ± 0.2 

Se μg/g 4.7 ± 1.7 18 ± 1 4.8 ± 0.8 4.3 ± 1.1 33 ± 2 10 ± 4 

Si wt% < 0.03 ± 0.01 < 0.1 ± 0 < 0.02 ± 0.01 0.02 ± 0.01 0.07 ± 0.06 2.47 ± 0.6 

Sm μg/g < 0.008 ± 0.003 < 0.04 ± 0.06 < 0.005 ± 0.001 0.034 ± 0.003 0.034 ± 0.033 1.6 ± 0.3 

Sr μg/g 3.1 ± 0.8 9.7 ± 2.5 18 ± 0 13 ± 3 31 ± 3 81 ± 7 

Ta μg/g 0.019 ± 0.008 0.12 ± 0.02 0.009 ± 0.002 0.018 ± 0.01 < 0.03 ± 0.03 0.17 ± 0.05 

Tb μg/g < 0.002 ± 0.002 < 0.010 ± 0.004 < 0.001 ± 0.001 0.002 ± 0.001 < 0.005 ± 0.001 0.24 ± 0 

Te μg/g < 0.1 ± 0 0.62 ± 0.04 < 0.08 ± 0.01 < 0.09 ± 0.01 < 0.3 ± 0 < 0.7 ± 0.5 

Th μg/g < 0.009 ± 0.005 < 0.04 ± 0.05 < 0.006 ± 0.009 0.015 ± 0.014 0.034 ± 0.03 1.9 ± 0.2 

Tl μg/g < 0.07 ± 0.1 < 0.3 ± 0.2 < 0.04 ± 0.02 < 0.04 ± 0.06 < 0.1 ± 0.2 < 0.4 ± 0.6 

Tm μg/g < 0.002 ± 0 < 0.01 ± 0.01 < 0.001 ± 0 < 0.002 ± 0.001 < 0.005 ± 0.002 0.09 ± 0.014 

U μg/g < 0.007 ± 0.004 < 0.03 ± 0.06 0.044 ± 0.006 0.21 ± 0.06 0.2 ± 0 2 ± 0.3 

V μg/g < 0.9 ± 1.1 < 4 ± 5 < 0.6 ± 0.2 1.3 ± 0.9 2.7 ± 2 26 ± 2 

Y μg/g 0.004 ± 0.005 0.021 ± 0.015 0.016 ± 0.002 0.074 ± 0.023 0.088 ± 0.007 6.3 ± 0.2 

Yb μg/g < 0.009 ± 0.005 < 0.04 ± 0 < 0.005 ± 0.003 < 0.006 ± 0.004 < 0.02 ± 0.01 0.59 ± 0.01 

Zn μg/g 49 ± 7 130 ± 0 23 ± 1 30 ± 1 200 ± 0 110 ± 10 

Zr μg/g 0.04 ± 0.02 0.23 ± 0.04 0.25 ± 0.15 1.1 ± 0 0.33 ± 0.03 14 ± 1 

82
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

Table 4-11. Continued.

Element 

Concentration 

Unit 

Tilapia

liver 10 

DOLT-1 

standard 1 

DOLT-1 

standard 2 

DOLT-1 

certified 

DORM-1 

standard 1 

DORM-1 

certified 

Al μg/g 4700 ± 200 < 0.6 ± 2.3 < 0.5 ± 0.7 ND < 0.6 ± 1.3 ND

As μg/g 2.1 ± 0.4 8.6 ± 0.8 9 ± 0 10.1 ± 1.4 14 ± 0 17.7 ± 2.1

B μg/g < 30 ± 10 14 ± 3 17 ± 9 ND 30 ± 1 ND

Ba μg/g 76 ± 1 0.07 ± 0.03 0.06 ± 0 ND 0.1 ± 0.02 ND

Be μg/g < 0.9 ± 0.6 < 0.2 ± 0.1 < 0.2 ± 0.2 ND < 0.2 ± 0.1 ND

Bi μg/g 0.87 ± 0.05 0.006 ± 0.022 < 0.003 ± 0.004 ND < 0.004 ± 0 ND

Ca wt% 0.8 ± 0.02 0.06 ± 0.008 0.057 ± 0.004 ND 0.096 ± 0.01 ND

Cd μg/g < 0.2 ± 0.1 3.7 ± 0.4 4 ± 0.1 4.2 ± 0.3 0.05 ± 0.04 0.09 ± 0.01

Ce μg/g 12 ± 0 0.007 ± 0.004 0.01 ± 0.002 ND 0.006 ± 0.002 ND

Co μg/g 2.7 ± 0.4 0.14 ± 0.03 0.11 ± 0 0.157 ± 0.037 < 0.04 ± 0.05 0.049 ± 0.014

Cr μg/g 14 ± 8 < 1 ± 0 < 1 ± 1 0.4 ± 0.07 3 ± 1 3.6 ± 0.4

Cs μg/g < 5 ± 1 < 1 ± 1 < 0.9 ± 0.3 ND 170 ± 10 ND

Cu μg/g 270 ± 20 20 ± 0 18 ± 1 20.8 ± 1.2 4.8 ± 0.5 5.22 ± 0.33

Dy μg/g 0.61 ± 0.04 < 0.005 ± 0.004 < 0.004 ± 0.004 ND < 0.005 ± 0.001 ND

Er μg/g 0.27 ± 0.06 < 0.008 ± 0.002 < 0.007 ± 0.004 ND < 0.008 ± 0.003 ND

Eu μg/g 0.16 ± 0 < 0.002 ± 0.001 < 0.002 ± 0.001 ND < 0.002 ± 0.002 ND

Fe μg/g 7500 ± 600 820 ± 10 750 ± 50 712 ± 48 61 ± 7 63.6 ± 5.3

Gd μg/g 0.74 ± 0.04 < 0.006 ± 0.002 < 0.005 ± 0.004 ND < 0.006 ± 0.004 ND

Hg ng/g 151 ± 15 -- 262 ± 42 225 ± 37 -- 798 ± 74

Ho μg/g 0.087 ± 0.001 < 0.001 ± 0.001 0.001 ± 0.001 ND < 0.001 ± 0 ND

K wt% 1.8 ± 0.3 0.99 ± 0.12 0.97 ± 0.05 1.01 ± 0.1 1.6 ± 0.1 1.59 ± 0.1

La μg/g 5.5 ± 0 0.006 ± 0.001 0.007 ± 0.001 ND 0.008 ± 0.002 ND

Li μg/g 6 ± 0.3 0.1 ± 0.1 < 0.1 ± 0 ND 0.2 ± 0 ND

Lu μg/g 0.026 ± 0.008 < 0.001 ± 0 < 0.001 ± 0 ND < 0.001 ± 0.001 ND

Mg wt% 0.42 ± 0.01 0.11 ± 0.01 0.1 ± 0.01 0.11 ± 0.015 0.12 ± 0.01 0.121 ± 0.013

Mn μg/g 66 ± 5 9 ± 1 8.6 ± 0.1 8.7 ± 0.5 2.5 ± 1.4 1.3 ± 0.3

Mo μg/g 13 ± 0 0.83 ± 0.37 0.74 ± 0.14 ND < 0.08 ± 0.06 ND

Na wt% 1.2 ± 0.2 0.66 ± 0.08 0.66 ± 0.04 0.73 ± 0.07 0.77 ± 0.05 0.8 ± 0.06

Nd μg/g 5.3 ± 0.2 < 0.008 ± 0.003 0.011 ± 0.006 ND 0.008 ± 0.006 ND

Ni μg/g 7.2 ± 0.6 0.4 ± 0.1 0.4 ± 0.1 0.26 ± 0.06 0.9 ± 0.1 1.2 ± 0.3

P wt% 1.29 ± 0.21 1.19 ± 0.2 1.12 ± 0.3 ND 1.01 ± 0.24 ND

Pb μg/g 9.3 ± 0.6 1.8 ± 0.2 1.1 ± 0.1 1.36 ± 0.29 0.28 ± 0.13 0.4 ± 0.12

Pd μg/g 0.097 ± 0.024 < 0.008 ± 0.004 < 0.007 ± 0.006 ND < 0.008 ± 0.005 ND

Pr μg/g 1.4 ± 0 < 0.002 ± 0.001 < 0.002 ± 0.001 ND < 0.002 ± 0.001 ND

Rb μg/g 18 ± 0 3.7 ± 0.4 3.5 ± 0.2 ND 5.9 ± 0.5 ND

Re μg/g < 0.02 ± 0 < 0.004 ± 0 < 0.004 ± 0 ND < 0.004 ± 0.001 ND

S wt% 1.15 ± 0.07 1.63 ± 0.07 1.53 ± 0.17 ND 0.99 ± 0.11 ND

Sb μg/g 0.53 ± 0.34 < 0.03 ± 0.02 < 0.03 ± 0.02 ND < 0.03 ± 0.01 ND

Se μg/g 18 ± 3 5.8 ± 1.2 5.3 ± 0.7 7.34 ± 0.42 1.1 ± 0.1 1.62 ± 0.12

Si wt% 0.38 ± 0.02 0.02 ± 0.03 < 0.02 ± 0.01 ND < 0.02 ± 0 ND

Sm μg/g 0.96 ± 0.06 < 0.005 ± 0.007 0.006 ± 0.005 ND < 0.005 ± 0.003 ND

Sr μg/g 70 ± 2 4.3 ± 0.5 4.4 ± 0.2 ND 5.4 ± 0.4 ND

Ta μg/g 0.041 ± 0.035 0.025 ± 0.006 0.011 ± 0.003 ND 0.013 ± 0.001 ND

Tb μg/g 0.093 ± 0.004 < 0.001 ± 0.001 < 0.001 ± 0.001 ND < 0.001 ± 0.001 ND

Te μg/g < 0.4 ± 0.4 < 0.08 ± 0.04 < 0.07 ± 0.03 ND < 0.08 ± 0.02 ND

Th μg/g 0.81 ± 0.03 < 0.006 ± 0.002 < 0.005 ± 0.003 ND < 0.006 ± 0.003 ND

Tl μg/g < 0.2 ± 0.1 < 0.04 ± 0.09 < 0.04 ± 0.03 ND < 0.04 ± 0.03 ND

Tm μg/g 0.031 ± 0.008 < 0.001 ± 0 < 0.001 ± 0 ND < 0.001 ± 0 ND

U μg/g 1.2 ± 0 0.023 ± 0.005 0.023 ± 0.002 ND < 0.004 ± 0.001 ND

V μg/g 9.8 ± 4.9 0.7 ± 0.2 < 0.5 ± 0.3 ND < 0.6 ± 0.2 ND

Y μg/g 3 ± 0.1 0.003 ± 0.002 0.004 ± 0.002 ND 0.003 ± 0.001 ND

Yb μg/g 0.21 ± 0.05 < 0.005 ± 0.001 < 0.005 ± 0.003 ND < 0.005 ± 0.005 ND

Zn μg/g 190 ± 20 93 ± 0 91 ± 13 ND 19 ± 3 ND

Zr μg/g 6 ± 0.1 0.05 ± 0.01 0.05 ± 0.01 ND 0.04 ± 0.03 ND

83
Barber and others, 2003, U.S. Geological Survey Water Resources Investigations Report 03-4129 

Whole Gambusia

Tilapia filet 1

Tilapia filet 3

Tilapia filet 4

Tilapia filet 5

Tilapia filet 6

Tilapia filet 8

Tilapia filet 10

Tilapia liver 1

Tilapia liver 5

Tilapia liver 6

Tilapia liver 7

Tilapia liver 10

0

2

4

a

ARSENIC CONCENTRATION,

in micrograms per gram

SPECIMEN Whole Gambusia

Tilapia filet 1

Tilapia filet 3

Tilapia filet 4

Tilapia filet 5

Tilapia filet 6

Tilapia filet 8

Tilapia filet 10

Tilapia liver 1

Tilapia liver 5

Tilapia liver 6

Tilapia liver 7

Tilapia liver 10

0

10

20

30

40

50

60

b

COPPER CONCENTRATION,

in micrograms per gram

SPECIMEN

280 270

Whole Gambusia

Tilapia filet 1

Tilapia filet 3

Tilapia filet 4

Tilapia filet 5

Tilapia filet 6

Tilapia filet 8

Tilapia filet 10

Tilapia liver 1

Tilapia liver 5

Tilapia liver 6

Tilapia liver 7

Tilapia liver 10

0

20

40

60

80

100

120

140

160

c

MERCURY CONCENTRATION,

in nanograms per gram

SPECIMEN

151

Whole Gambusia

Tilapia filet 1

Tilapia filet 3

Tilapia filet 4

Tilapia filet 5

Tilapia filet 6

Tilapia filet 8

Tilapia filet 10

Tilapia liver 1

Tilapia liver 5

Tilapia liver 6

Tilapia liver 7

Tilapia liver 10

0.0

0.2

0.4

0.6

0.8

1.0

d

LEAD CONCENTRATION,

in micrograms per gram

SPECIMEN

10 9.3

Less than

Figure 4-8. Plots of (a) arsenic, (b) copper, (c) mercury, and (d) lead concentrations (dry weight) in 

whole-body Gambusia and selected body parts of Tilapia specimens collected from the Cobble and 

Hayfield wetlands, February 14, 2000. 

84
Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

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Organic and trace element contaminants in water, biota, sediment, and SPMD at the Tres Rios Treatment Wetlands, Phoenix, Arizona

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89