Grantee Research Project Results

Final Report: Regional Movement of Toxics

EPA Grant Number: R825433C025
Subproject: this is subproject number 025 , 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: UC Davis Center for Children's Environmental Health and Disease Prevention
Center Director: Van de Water, Judith
Title: Regional Movement of Toxics
Investigators: Matsumura, Fumio , Reuter, John E. , Goldman, Charles R.
Institution: University of California - Davis
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1996 through September 30, 2000
RFA: Exploratory Environmental Research Centers (1992) RFA Text |  Recipients Lists
Research Category: Center for Ecological Health Research , Targeted Research

Objective:

The objectives of this research project were to: (1) investigate the bioaccumulation of organochlorines in the fish and amphibian communities of Sierra Nevada bodies of water; and (2) investigate the importance of these compounds as biomarkers of pollution.

Summary/Accomplishments (Outputs/Outcomes):

Atmospheric transport provides a potentially important pathway whereby organic and metal contaminants can reach otherwise "pristine" regions. In previous work funded by the Center for Ecological Health Research, it was found that lake trout and kokanee salmon from Lake Tahoe both contained unexpectedly significant levels of residues of the following organochlorine pollutants: polychlorinated biphenyls (PCBs); p,p'-dichlorodiphenyldichloroethane (DDE); and toxaphene. Because Lake Tahoe is not subject to direct contamination by industrial discharges or agricultural runoff, the presence of these pollutants in biota suggests that atmospheric transport (possibly from the pesticide-rich Central Valley) likely is the significant source of input not only to Lake Tahoe, but also to other Sierra Nevada subalpine and alpine lakes. Similar atmospheric processes that transport nitrogen and organochlorine chemicals into the Sierra Nevada also may contribute, at least in part, to the deposition of mercury into this region. The ultimate incorporation of these toxics into the aquatic food web raises questions regarding biological health/stress, but it also indicates that organochlorine residues can serve as biomarkers to assess exposure to these organic compounds at both the organism and ecosystem levels. For this study, we measured organochlorine concentrations in sediment cores taken from Lake Tahoe to determine historical rates of deposition.

We also conducted two studies of PCB as related to frogs. In the first study, we investigated the distribution pattern of Pacific tree frogs showing PCB bioaccumulation throughout the Sierra Nevada. In the second study, we investigated the molecular biological effects of PCB on leopard frogs, a surrogate species for the indigenous Sierra Nevada mountain yellow-legged frog. Other studies have shown that the DDE residues in the mountain yellow-legged frogs throughout the Sierra Nevada are very unevenly distributed with respect to geography. There were ultraclean (no DDE residue) pockets between very high mountain ranges and on several locations on the eastern slope immediately east of high mountain ranges. These clean areas are the locations in which the mountain yellow-legged frog is still found.

The following activities were accomplished:

• We discovered that relatively high amounts of PCB and toxaphene residues are present in the lake trout of Lake Tahoe. The amounts of PCB present in lake trout samples are similar to what has been found in Lake Superior. Slightly higher levels of PCB residues found in Lake Michigan have been considered to be the main cause for the failure of natural lake trout reproduction there. This discovery alerts other researchers and environmental agencies to a potential similar danger in Lake Tahoe.

• We showed that PCB, toxaphene, and organochlorine pesticides can reach even the most remote areas of the Sierra Nevada, as judged by their presence in rainbow trout. Small, but significant, amounts of PCB and organochlorine pesticide residues are found in rainbow trout samples from even very remote, high-altitude lakes and streams of the Sierra Nevada. This finding suggests that PCB contamination can be unexpectedly widespread, perhaps prompting stronger efforts to monitor PCB and other organochlorine pesticides.

• The pattern of PCB residue distributions indicates that these pollutants are introduced into high-altitude Sierra Nevada regions through atmospheric transport. PCB residues have been found to be distributed according to an altitude-dependent fashion; the higher the altitude, the lower its residue levels. In contrast, toxaphene residues are distributed ubiquitously, indicating that the route and the mechanism of transport of these two chemical complexes are different. These results are significant because they suggest a possible source of PCB pollution (California’s intensely agricultural Central Valley), and thereby point to a course of abatement.

• PCB residue distribution patterns in Pacific tree frog tadpoles indicate that there is a distinct difference in the composition of residues within the frogs: those from the western slope contain a higher proportion of low-chlorinated congeners, and those from the eastern slope contain highly chlorinated congeners. PCB consists of more than 200 similar compounds called congeners, many with varying degrees of chlorinated biphenyls. It is known that lower chlorinated congeners are more volatile than more highly chlorinated ones. The above observation indicates that there is a definite effect of high-altitude mountain ranges on capturing even volatile constituents of PCBs. (A useful analogy for illustrating this phenomenon is the condensation of atmospheric water by high-altitude mountains.) This information should be kept in mind in further research effort, especially those involving high-altitude sampling.

• We determined that PCBs, such as Aroclor 1260, can mimic the effect of cold exposure in leopard frogs. This finding is very interesting because it provides a possible explanation (decreased cold tolerance) for why numbers of mountain yellow-legged frogs—an endangered indigenous Sierra Nevada frog species—are declining. This information can be used in further research into the phenomenon of declining yellow-legged frogs.

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., RFA, Scientific Discipline, Waste, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, State, Fate & Transport, Monitoring/Modeling, Environmental Monitoring, Ecological Risk Assessment, Ecology and Ecosystems, fate and transport, monitoring, food chain, environmental measurement, organochloriines, biomarkers, kinetics, PCBs, forest ecosystem, fish consumption, emissions, mercury cycling, modeling, air pollution, detection system, watershed influences, emission control, ecological risk, field detection, Lake Tahoe, California (CA), analytical models, atmospheric deposition, bioaccumulation

Relevant Websites:

http://ice.ucdavis.edu/cehr/ Exit

Progress and Final Reports:

Original Abstract

1997

1998

1999 Progress Report

Main Center Abstract and Reports:

R825433    UC Davis Center for Children's Environmental Health and Disease Prevention

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