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1996 Progress Report: Wildlife Bioaccumulation and Effects
EPA Grant Number: R825433C014Subproject: this is subproject number 014 , 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: Wildlife Bioaccumulation and Effects
Investigators: Anderson, Daniel
Institution: University of California - Davis
EPA Project Officer: Levinson, Barbara
Project Period: October 1, 1996 through September 30, 2000
Project Period Covered by this Report: October 1, 1996 through September 30, 1997
RFA: Exploratory Environmental Research Centers (1992)
Research Category: Center for Ecological Health Research , Targeted Research
Description:
Objective:Current Status:
Past work on avifauna at Clear Lake has developed an excellent picture of the current exposure of fish-eating birds to chlorinated hydrocarbons and mercury. The species receiving most intense investigation have been osprey and western/Clarke's grebes. Osprey virtually disappeared from Clear Lake in the application era, and the decline of western grebes was the basis for a classic paper on food chain accumulation of chlorinated hydrocarbons. Osprey have had 13-20 successful nests each year on Clear Lake and fledging rates are consistent with at least maintenance reproduction. Western grebes are abundant, but are breeding at very low rates, despite apparently good condition. In comparison to western grebes at control Klamath and Eagle Lakes, grebes at Clear Lake have significantly higher mercury burdens. The situation with chlorinated hydrocarbons is quite different. DDT metabolites such as DDE are at regional background levels. DDD body burdens have fallen dramatically from levels in the 1960s and 70s.
Future Plans:
Future work will concentrate upon better understanding the current effects of mercury contamination at Clear Lake and upon reconstructing the past exposures of birds to the multiple stress of chlorinated hydrocarbons and mercury. Several important questions are outstanding regarding current exposure to mercury and its effects. Both grebes and osprey are migratory birds, and it is never clear if the mercury burden of a given bird was acquired in the habitat where it was collected or at some remote location. We will pursue both experimental and observational techniques to address this question.
Experimental studies of caged birds and mammals fed foods collected at different lakes will be used to investigate the dynamics of acquisition and depuration. These experiments will also test non-invasive assays for body burdens, especially feathers and hair. Preliminary results of the feather assay are moderately promising, but the dynamics of deposition of Hg in feathers over the molt cycle is complex. We will also experiment with releasing birds carrying radiotelemetry transmitters to track movements birds to estimate exposures. Initially these experiments will be conducted with a tractable sentinel species (mallard ducks or mink), with the ultimate aim of conducting similar experiments on grebes.
Observational studies will include continued monitoring of populations of western grebes and osprey at Clear Lake. It is still not clear why western grebes visit Clear Lake in large numbers, and yet fail to reproduce at even near replacement levels. Human disturbance, mercury body burdens, and food availability are all possible stresses. Our current hypothesis is that some combination of these stresses prevent successful reproduction at Clear Lake, and that the Clear Lake habitat is currently a sink for a regional population that is reproducing successfully elsewhere. Alternatively, western grebes are said to have reproduce successfully in Clear Lake in the 1980s before our study began, and reproduction may be episodic in time rather than patchy in space. We will test the regional part of this hypotheses defining the regional population structure the western grebe using genetic markers. Is the Clear Lake population distinctive or is it merely one habitat occupied by a much larger population?
Most likely, the combined stresses of mercury and chlorinated hydrocarbons had the greatest impact on fish-eating wildlife at Clear Lake in the 1950s and 60s when DDD body burdens are known to have been high and the Sulphur Bank Mine was still in operation. Unfortunately, scientists interested in the DDD question did not measure mercury body burdens in the years when DDD levels were high. We have located some museum specimens and stored samples which can be resampled for Hg. We plan to calibrate a non-destructive X-ray fluorescence method for estimating mercury in feathers and other tissues remaining in study skins, and make an intensive search for specimens to reanalyze as far back into the past as possible. In conjunction with Project A1.x on the history of anthropogenic effects, it should be possible to reconstruct the time course of exposure of wildlife to both toxicants. This information, in turn, will be the basis for experiments designed to test the multiple stressors hypothesis.
Supplemental Keywords:migratory birds, mercury, toxins, ecosystem. , Ecosystem Protection/Environmental Exposure & Risk, Water, Scientific Discipline, RFA, Water & Watershed, Aquatic Ecosystem Restoration, Ecology, Aquatic Ecosystems & Estuarine Research, Aquatic Ecosystem, Hydrology, mercury transport, Watersheds, Ecology and Ecosystems, Environmental Monitoring, lakes, migratory birds, environmental rehabilitation, mesocosm experiments, wildlife bioaccumulation, watershed management, esturarine eutrophication, mercury contamination in fish, Clear Lake, bioaccumulation, nutrient stress, eutrophication, organochlorides, diagnostic indicators, lake ecosystems, wetlands, ecological recovery, riparian ecosystem integrity, wetland restoration, fish consumption, algal blooms, aquatic ecosystems, environmental stress, nutrient loading, lake ecosysyems, riparian habitat, watershed influences, nutrients, restoration strategies
Progress and Final Reports:
Original Abstract
2000 Progress Report
Final Report
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