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Final Report: Molecular, Cellular and Animal Biomarkers of Exposure and Effect
EPA Grant Number: R825433C044Subproject: this is subproject number 044 , established and managed by the Center Director under grant R825433
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: EERC - Center for Ecological Health Research (Cal Davis)
Center Director: Rolston, Dennis E.
Title: Molecular, Cellular and Animal Biomarkers of Exposure and Effect
Investigators: Wilson, Barry W.
Institution: University of California - Davis
EPA Project Officer: Levinson, Barbara
Project Period: October 1, 1996 through September 30, 2000
RFA: Exploratory Environmental Research Centers (1992)
Research Category: Center for Ecological Health Research , Targeted Research
Description:
Objective:The objective of this research project was to develop and apply biochemical biomarkers of exposure and effect to avian and aquatic ecosystems. Our methods for developing these biomarkers included enzyme assays optimized for the concerned species. We investigated the use of cholinesterases (CHEs), including ethoxyresorufin-O-deethylase (EROD) and neuropathy target esterase. We also developed antibody and gas liquid chromatography (GLC) assays for detection of pesticide residues, used hormone assays to noninvasively examine the reproductive potential of wild animals exposed to pesticides, and produced cell cultures for detecting toxicity effects. Lastly, we performed chemical analyses for pesticide runoff studies examining the organophosphate (OP) diazinon and the pyrethroid esfenvalerate in several orchard sites in California.
Summary/Accomplishments (Outputs/Outcomes):CHEs provide histochemical and enzymatic methods to study the action of pesticides on avian, fish, and mammalian development and monitor for exposure to OP ester agents. We developed fluorescent EROD assays using tissue microsomal preparations and cell cultures to provide an indication of the mixed function oxidase activities of liver and other tissues of birds and mammals. The neuropathy target esterase assay singles out an enzyme of nervous and other tissues implicated in OP-induced delayed neuropathy, a disorder brought about by certain OPs, including the pesticides chlorpyrifos and isofenfos. Our antibody and GLC assays detect pesticide residues, and they are routinely performed to establish pesticide residue levels in tank mixes, air, ground, streams, and on trees. These assays also were used to establish the amount of pesticide residue remaining on the feet of live-captured and sentinel mammals and birds after pesticide application.
Biomarkers are needed for rapidly determining the reproductive state of birds, mammals, and other species at risk in the environment. One such biomarker is possible by using antibodies to fecal metabolites of hormones as a means to assess the reproductive state of the animal in question. Working with Bill Lasley and Joseph Billitti (a graduate student at that time), we established and validated a method for determining the testosterone level in mouse species. Joseph Billitti, along with Michael Johnson, then applied this method to study an endangered mouse species at Mare Island, CA, and the potential reproductive effects of the controversial fuel additive methyl tert-butyl ether. Highly differentiated cell cultures offer safe and cost-effective opportunities to detect toxicity effects, establish species differences, and study metabolic conversions. Toxicity differences established in the laboratory on the cells of different species can be verified on the animals in the laboratory and in the field. We developed an array of primary cultures for these purposes. Jay Davis (who was then a graduate student) and Michael Fry used avian liver cell cultures to study the stimulation of EROD activity from eggs obtained from sites of suspected contamination along the Pacific Coast.
In the dormant orchard-spray component of our study, we found that cover crops reduced runoff and toxicity, and that the pyrethroid esfenvalerate was toxic to test fish species (e.g., fathead minnow) below the level of detectability (0.2 µ/L) of our gas chromatograph. Recent studies are focusing on the hypothesis that spraying early in the rainy season reduces the runoff because of infiltration and breakdown of chemicals.
As a final note, Jon Hamm (who was then a graduate student) made a major discovery during the course of this project: diazinon exposure damages the neural retina of developing fish. The mechanism of this developmental injury and its possible impact on the aquatic environment needs intensive further study, as well as consideration by regulatory agencies.
The following activities were accomplished:
• We improved CHE assays to detect pesticide and chemical agent exposures to aquatic, terrestrial, and avian vertebrates, including humans. This development enhances the ease-of-use and reliability of a commonly used method to determine OP chemical exposures. Our improved assays will be used by state and national agencies, corporations, and academic researchers.
• Data from our laboratory prompted California to require harmonization of clinical blood CHE tests. This enables the comparison of results between laboratories that use different methods. Harmonized CHE tests will be useful to state and national agencies, physicians, wildlife organizations, and anyone detecting pesticide exposure in humans and wildlife.
• We developed and validated reactivation methods to detect anti-CHE exposures. These methods enable investigators to determine pesticide exposure by enzyme assays in the absence of baseline data, and will be valuable to state and national agencies, wildlife organizations, and the U.S. Environmental Protection Agency (EPA).
• Our data suggest that exposure to OP pesticides may alter the DNA of sperm cells. If validated by further work, this finding raises the possibility that pesticide exposures may damage germ cells. Agencies such as the National Institutes of Health, the U.S. EPA, the National Science Foundation, and chemical companies will find this information useful.
• We developed and validated antibody methods to estimate the testosterone content, and hence reproductive state, of mammals using fecal assays. This method provides a noninvasive means of examining the reproductive state of threatened or endangered species. Wildlife agencies, investigators, and the U.S. EPA will all find this a beneficial tool in their work.
• We developed models for predicting and mediating the impact of pesticide runoff after dormant spraying. Runoff models permit remediation designs to reduce pesticide use and impact. Our model will be useful to growers, water boards, and other state and national agencies, including the U.S. EPA.
• Recently, our methodology provided a basic research tool for examining the claim that pesticides (as determined by CHEs) are causing the decline of amphibia. State and national wildlife agencies can use this tool to investigate changes in amphibian populations.
Supplemental Keywords:ecosystem, ecosystem protection, environmental exposure and risk, geographic area, international cooperation, water, terrestrial ecosystems, aquatic ecosystem, aquatic ecosystem restoration, aquatic ecosystems and estuarine research, biochemistry, ecological effects, ecological indicators, ecological monitoring, ecology and ecosystems, environmental chemistry, restoration, state, water and watershed, watershed, watershed development, watershed land use, watershed management, watershed modeling, watershed restoration, watershed sustainability, agricultural watershed, exploratory research environmental biology, California, CA, Clear Lake, Lake Tahoe, anthropogenic effects, aquatic habitat, biogeochemical cycling, ecological assessment, ecology assessment models, ecosystem monitoring, ecosystem response, ecosystem stress, environmental stress, environmental stress indicators, fish habitat, hydrologic modeling, hydrology, integrated watershed model, lake ecosystems, lakes, land use, nutrient dynamics, nutrient flux, water management options, water quality, wetlands. , Ecosystem Protection/Environmental Exposure & Risk, Water, Scientific Discipline, Health, RFA, ECOSYSTEMS, Ecosystem/Assessment/Indicators, Endocrine Disruptors - Environmental Exposure & Risk, Water & Watershed, exploratory research environmental biology, Aquatic Ecosystems & Estuarine Research, endocrine disruptors, Terrestrial Ecosystems, Ecological Monitoring, Aquatic Ecosystem, Ecological Indicators, Biochemistry, Watersheds, Environmental Chemistry, Ecological Effects - Environmental Exposure & Risk, Ecosystem Protection, Monitoring/Modeling, Ecology and Ecosystems, Environmental Monitoring, Endocrine Disruptors - Human Health, biomarkers, runoff, water quality, watershed modeling, watershed land use, animal models, endocrine disrupting chemicals, watershed management, watershed restoration, immunoassay, protein kinase, ecological risk, ecology assessment models, ecosystem health, fish, bioindicator, environmental stress indicators, anthropogenic effects, land use, wetlands, models, pesticide exposure, watershed development, molecular markers, aquatic habitat, agricultural watershed, aquatic ecosystems, environmental stress, pesticides, lake ecosysyems, watershed sustainablility, ecological assessment, water management options, agrochemicals, ecosystem stress, ecosystem response
Relevant Websites:
Progress and Final Reports:
1999 Progress Report
2000 Progress Report
Original Abstract
Main Center Abstract and Reports:
R825433 EERC - Center for Ecological Health Research (Cal Davis)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825433C001 Potential for Long-Term Degradation of Wetland Water Quality Due to Natural Discharge of Polluted Groundwater
R825433C002 Sacramento River Watershed
R825433C003 Endocrine Disruption in Fish and Birds
R825433C004 Biomarkers of Exposure and Deleterious Effect: A Laboratory and Field Investigation
R825433C005 Fish Developmental Toxicity/Recruitment
R825433C006 Resolving Multiple Stressors by Biochemical Indicator Patterns and their Linkages to Adverse Effects on Benthic Invertebrate Patterns
R825433C007 Environmental Chemistry of Bioavailability in Sediments and Water Column
R825433C008 Reproduction of Birds and mammals in a terrestrial-aquatic interface
R825433C009 Modeling Ecosystems Under Combined Stress
R825433C010 Mercury Uptake by Fish
R825433C011 Clear Lake Watershed
R825433C012 The Role of Fishes as Transporters of Mercury
R825433C013 Wetlands Restoration
R825433C014 Wildlife Bioaccumulation and Effects
R825433C015 Microbiology of Mercury Methylation in Sediments
R825433C016 Hg and Fe Biogeochemistry
R825433C017 Water Motions and Material Transport
R825433C018 Economic Impacts of Multiple Stresses
R825433C019 The History of Anthropogenic Effects
R825433C020 Wetland Restoration
R825433C021 Sierra Nevada Watershed Project
R825433C022 Regional Transport of Air Pollutants and Exposure of Sierra Nevada Forests to Ozone
R825433C023 Biomarkers of Ozone Damage to Sierra Nevada Vegetation
R825433C024 Effects of Air Pollution on Water Quality: Emission of MTBE and Other Pollutants From Motorized Watercraft
R825433C025 Regional Movement of Toxics
R825433C026 Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
R825433C027 Source Load Modeling for Sediment in Mountainous Watersheds
R825433C028 Stress of Increased Sediment Loading on Lake and Stream Function
R825433C029 Watershed Response to Natural and Anthropogenic Stress: Lake Tahoe Nutrient Budget
R825433C030 Mercury Distribution and Cycling in Sierra Nevada Waterbodies
R825433C031 Pre-contact Forest Structure
R825433C032 Identification and distribution of pest complexes in relation to late seral/old growth forest structure in the Lake Tahoe watershed
R825433C033 Subalpine Marsh Plant Communities as Early Indicators of Ecosystem Stress
R825433C034 Regional Hydrogeology and Contaminant Transport in a Sierra Nevada Ecosystem
R825433C035 Border Rivers Watershed
R825433C036 Toxicity Studies
R825433C037 Watershed Assessment
R825433C038 Microbiological Processes in Sediments
R825433C039 Analytical and Biomarkers Core
R825433C040 Organic Analysis
R825433C041 Inorganic Analysis
R825433C042 Immunoassay and Serum Markers
R825433C043 Sensitive Biomarkers to Detect Biochemical Changes Indicating Multiple Stresses Including Chemically Induced Stresses
R825433C044 Molecular, Cellular and Animal Biomarkers of Exposure and Effect
R825433C045 Microbial Community Assays
R825433C046 Cumulative and Integrative Biochemical Indicators
R825433C047 Mercury and Iron Biogeochemistry
R825433C048 Transport and Fate Core
R825433C049 Role of Hydrogeologic Processes in Alpine Ecosystem Health
R825433C050 Regional Hydrologic Modeling With Emphasis on Watershed-Scale Environmental Stresses
R825433C051 Development of Pollutant Fate and Transport Models for Use in Terrestrial Ecosystem Exposure Assessment
R825433C052 Pesticide Transport in Subsurface and Surface Water Systems
R825433C053 Currents in Clear Lake
R825433C054 Data Integration and Decision Support Core
R825433C055 Spatial Patterns and Biodiversity
R825433C056 Modeling Transport in Aquatic Systems
R825433C057 Spatial and Temporal Trends in Water Quality
R825433C058 Time Series Analysis and Modeling Ecological Risk
R825433C059 WWW/Outreach
R825433C060 Economic Effects of Multiple Stresses
R825433C061 Effects of Nutrients on Algal Growth
R825433C062 Nutrient Loading
R825433C063 Subalpine Wetlands as Early Indicators of Ecosystem Stress
R825433C064 Chlorinated Hydrocarbons
R825433C065 Sierra Ozone Studies
R825433C066 Assessment of Multiple Stresses on Soil Microbial Communities
R825433C067 Terrestrial - Agriculture
R825433C069 Molecular Epidemiology Core
R825433C070 Serum Markers of Environmental Stress
R825433C071 Development of Sensitive Biomarkers Based on Chemically Induced Changes in Expressions of Oncogenes
R825433C072 Molecular Monitoring of Microbial Populations
R825433C073 Aquatic - Rivers and Estuaries
R825433C074 Border Rivers - Toxicity Studies