Use of Passive Samplers for Detecting Spatial Distribution of Organic Contaminants in Lake Mead, Nevada, U.S.A M. R. Rosen, S. L. Goodbred, D.A. Alvarez, and Thomas J. Leiker US Geological Survey

This work is part of an ongoing study initiated in 1995 to assess potential for endocrine disruption in Lake Mead. Objectives Determine presence and potential sources of endocrine disrupting compounds (EDCs) in Lake Mead National Recreation Area (LAME) using passive samplers and sediment cores. Importance of study Determine what EDCs aquatic organisms might be exposed to at various locations in LAME and their potential sources. Background

Water Quality Issues in Las Vegas Bay, Lake Mead Historic use chemicals present in sediment & biota (i.e. chlorinated pesticides, PCB’s etc.) Historic use chemicals present in sediment & biota (i.e. chlorinated pesticides, PCB’s etc.) Chemicals from manufacturing plants and defense related industries since 1940’s. (e.g. perchlorate etc). Chemicals from manufacturing plants and defense related industries since 1940’s. (e.g. perchlorate etc). Tertiary treated effluent (currently >180 million gallons daily, expected to increase to 400 million gallons daily by 2050). Tertiary treated effluent (currently >180 million gallons daily, expected to increase to 400 million gallons daily by 2050). Storm-water runoff and other non-point sources Storm-water runoff and other non-point sources

1950 Pop 47, Pop 1,300,000 Population Growth in Las Vegas Valley

Overton Arm Colorado R. Inflow Las Vegas Bay Bay Lake Mead National Recreation Area Sampling Sites March, 2006 Colorado R. Outflow (Willow Beach) SentinelIsland Las Vegas Wash Below STPs Las Vegas Wash Above STPs

Study Design Three 36” SPMDs, 3 POCIS discs both pharmaceutical and pesticide were deployed at 7 sites in LAME for one month in February 2006 all at 8 m water depth Three 36” SPMDs, 3 POCIS discs both pharmaceutical and pesticide were deployed at 7 sites in LAME for one month in February 2006 all at 8 m water depth SPMDs deployed in vertical gradient at Las Vegas Bay site SPMDs deployed in vertical gradient at Las Vegas Bay site Analytical chemistry done on extracts by GC/MS Analytical chemistry done on extracts by GC/MS Performance Reference Compounds (PRCs) used in SPMDs Performance Reference Compounds (PRCs) used in SPMDs

What are SPMDs and POCIS Samplers? Hydrophilic compounds K ow <3.0 POCIS consists of a microporous membrane containing various solid phase sequestering media Hydrophobic compounds K ow >3.0 SPMD consists of Low density polyethylene lay-flat tubing containing lipid (fat-like organic compound made of triolein) similar to fish fat

Vertical gradient Sampling Setup POCIS 8 M

Deployment and Retrieval of Samplers

Different Blank Used at Each Site If compound detected in blank: Concentration in blank subtracted from reported value If compound detected in blank: Concentration in blank subtracted from reported value Above WWTPs Below WWTPs

Performance Reference Compounds used for SPMDs to calculate concentrations Anthracene – d 10 Anthracene – d 10 Chrysene – d 12 Chrysene – d 12 Las Vegas Bay inflowBoulder Basin site

Blanks are Important What did we find in blanks? Acetophenone fragrance (soaps, creams) Acetophenone fragrance (soaps, creams) Benzophenone sunscreens Benzophenone sunscreens Oyxbenzone sunscreens Oyxbenzone sunscreens Di limonene citrus based solvent Di limonene citrus based solvent Methyl naphthalene found in air, cigarettes Methyl naphthalene found in air, cigarettes Methyl salicylate deep heat therapy Methyl salicylate deep heat therapy Octylphenol surfactant in soaps Octylphenol surfactant in soaps Compound Uses

Total Compounds Detected SPMD Total Compounds (30) Number of EDCs (17) POCIS Total Compounds (28) Number of EDCs (7)

EDCs Detected in Las Vegas Wash and Lake Mead National Recreation Area PCPs PCPs Galoxolide Galoxolide Tonalide Tonalide 4-tert-octylphenol 4-tert-octylphenol Triclosan Triclosan PAHs PAHs Pyrene Pyrene Anthracene Anthracene Phenanthrene Phenanthrene Benzo (a) pyrene Benzo (a) pyrene Pesticides Chlorphrifos o,p’ DDE Trifluralin HCB Trans & Cis Chlordane Industrial BDE (47,99,100,138, 146,180 )

Hydrophobic Compounds Total concentration (µg/L) and number of detects Hydrophobic Compounds Total concentration (µg/L) and number of detects Overton Arm (3) Colorado R Inflow 0.02 (6) Colorado R Outflow (6) Sentinel Island (5) Las Vegas Bay 0.06 (16) Las Vegas Wash Below STPs 0.45 (17) Las Vegas Wash Above STPs (12)

Where are EDCs Coming From? Example of Galaxolide (µg/L) at 8 m depth in Lake Mead Overton Arm < Colorado R Inflow < Colorado R Outflow < Sentinel Island Las Vegas Bay 0.06 Las Vegas Wash Below STPs 0.4 Las Vegas Wash Above STPs <0.0005

Where are EDCs Coming From? Example of Naphthalene (petrogenic) (µg/L) at 8 m depth in Lake Mead Overton Arm < Colorado R Inflow 0.01 Colorado R Outflow Estimated Sentinel Island < Las Vegas Bay Las Vegas Wash Below STPs < Las Vegas Wash Above STPs <0.0009

Where are EDCs Coming From? Example of Pyrene (pyrogenic) (µg/L) at 8 m depth in Lake Mead Overton Arm < Colorado R Inflow < Colorado R Outflow < Sentinel Island < Las Vegas Bay Las Vegas Wash Below STPs < Las Vegas Wash Above STPs <

Vertical Gradient of Hydrophobic Contaminants in Las Vegas Bay

Hydrophilic Compounds ng/POCIS (pesticide EI and NCI) and # of detects Overton Arm 390 (8) Colorado R Inflow 0 (0) Colorado R Outflow 1,033 (5) Sentinel Island 74 (3) Las Vegas Bay 136 (1) Las Vegas Wash Below STPs 24,716 (11) Las Vegas Wash Above STPs 22,551 (11)

Effects in Male Carp Las Vegas Wash downstream of WWTPs From high to low, reproductive condition by site can be classified as: OA > LVB > LVW > WB Intersex fish found in Las Vegas Wash EDCs found in carp include Methyl Triclosan,PBDEs, DDT (and metabolites)

Effects in Male Largemouth Bass Relatively low KT levels and high E2/KT ratios in Las Vegas Bay males are consistent with reduced health and reproductive condition Only two sites have bass present No chemical data available yet The differences between sites were most evident just prior spawning period (March 2008)

Conclusions Las Vegas Wash below WWTPs major source of hydrophobic contaminants and EDCs in LAME Las Vegas Wash below WWTPs major source of hydrophobic contaminants and EDCs in LAME Sole source of Galaxolide and Tonalide, weakly estrogenic musk fragrances, is Las Vegas Wash below WWTPs. Sole source of Galaxolide and Tonalide, weakly estrogenic musk fragrances, is Las Vegas Wash below WWTPs. Hydrophilic compounds come from both sites in the Wash. Hydrophilic compounds come from both sites in the Wash. Main source of PAHs is petrogenic compounds from within lake (boats) Main source of PAHs is petrogenic compounds from within lake (boats) Very few EDCs coming from inflows at Overton Arm, Colorado R. or present below Hoover Dam. Very few EDCs coming from inflows at Overton Arm, Colorado R. or present below Hoover Dam. Overall, aquatic biota show impaired reproductive function in LVW and LVB and are most exposed to EDCs in LVW, Bay, and Boulder Basin, but other sources exist. Overall, aquatic biota show impaired reproductive function in LVW and LVB and are most exposed to EDCs in LVW, Bay, and Boulder Basin, but other sources exist.

Research Team USGS personnel Project coordinator: Michael R. Rosen Toxicologist: Steven Goodbred Fish Biologist: Reynaldo Patiño Chemist: David Alvarez Risk analyst: Greg Linder Fish microbiologist: Jill Jenkins Partners Toxicologist:Erik Orsak USFWS Foodweb biologist:Sudeep Chandra Microbiologist:Duane Moser