Chlorinated Hydrocarbons

EPA Grant Number: R825433C064
Subproject: this is subproject number 064 , 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: Chlorinated Hydrocarbons
Investigators: Goldman, Charles R. , Matsumura, Fumio
Institution: University of California - Davis
EPA Project Officer: Levinson, Barbara
Project Period: June 30, 1995 through June 30, 1998
RFA: Exploratory Environmental Research Centers (1992) RFA Text |  Recipients Lists
Research Category: Center for Ecological Health Research , Targeted Research


Atmospheric transport of toxic compounds provides a potential source of these pollutants to regions which are otherwise not directly impacted. In this section of the investigators' research, they plan to expand upon work previously funded by the Center to extend studies on bioaccumulation of organochlorines into the fish and amphibian communities of Sierra Nevada waterbodies. The importance of these compounds as biomarkers of pollution will also be investigated. Organochlorine and mercury concentrations will be measured in sediment cores taken from Lake Tahoe to determine historical rates of deposition.

Atmospheric transport provides a potentially important pathway whereby organic and the investigators metal contaminants can reach otherwise 'pristine' regions. In previous worked funded by the Center, it was found that lake trout and kokanee salmon from Lake Tahoe both contained unexpectedly significant levels of residues of the organochlorine pollutants PCB'S, p,p-DDE and toxaphene. The ultimate incorporation of these toxics into the aquatic food web raise both questions regarding biological health/stress, but also indicate that they can serve as biomarkers to assess exposure to these organic compounds at both the organism and ecosystem levels.


Lake Tahoe and other high altitude lakes in the Sierra Nevada provide a very interesting model of atmospheric transport. The source of these organochlorine chemicals are likely the agriculturally very active Central Valley. The prevailing winds blowing across California from west to east carry those chemicals. The rising air masses are known to release most of their moisture as precipitation on the western face of the mountains so much so that the eastern side of the crest is very dry making the boundary to the great desert areas of the western U.S. Such transport processes are selective, however, depending on the physicochemical nature of the chemicals including persistence and their mode of precipitation (snow, rain, particle-bound, etc.) For instance, the results of the research Linda Aston conducted in the Center indicate that despite the heavy use of organophosphates and carbamate in the Central Valley, their residues are seldom found at elevations higher than 1000 m. It has been found that DDE residues in the mountain yellow-legged frogs throughout the Sierra Nevada are very unevenly distributed. There were ultra-clean 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 where this endangered species is still found.

Building on previous research, plans for additional work with organochlorines includes:

  • Expand measurements to include other important fish species in Lake Tahoe, and correlate fish age with organochlorine body burden,
  • Examine deep lake sediment cores to determine historical time sequence of organochlorine deposition,
  • Map the long-range transport of these compounds from the central valley to the Sierra Nevada by surveying fish from other water bodies along a north-south and a west-east transect.
  • Expand our studies to two species of amphibians, Hyla regilla, Pacific trees frogs, which are relatively resistant to pollution and still found widely distributed in the high Sierra, and the mountain yellow-legged frog, Rana musicos, using mostly freeze-stored samples from many parts of the Sierra Nevada. The archived samples are being made available to us by the courtesy of Dr. Bradley Shaffer, UCD.

Expected Results:

Lake Tahoe is an ideal system to study the patterns of atmospheric transport and deposition of potentially toxic metal pollutants as well. Gold mining was extremely widespread in the Sierra Nevada during the late 1800s. During that period, mercury was mined in the California Coast Range and transported into the Sierras for use in the mining process. Since refining and retorting were important processes in the production of mercury at the Coastal Range locations, it can be hypothesized that atmospheric transport directly into the Sierra Nevada may have been significant. By correlating the date(s) of mercury changes down the core with historical information on mercury refining, burning of coal, incineration of solid waste, etc. investigators expect to better understand the importance of atmospheric-Hg transport in aquatic mercury dynamics. Since mercury has been identified nationwide as a major pollutant, the work planned is highly generalizable to other regions.

Supplemental Keywords:

Aquatic ecosystem, California, environmental assessment, atmospheric transport, atmospheric deposition, Ecosystem modeling, Lake Tahoe, Sierra Nevada, watersheds, aquatic food web, mercury., RFA, Scientific Discipline, Waste, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Chemical Mixtures - Environmental Exposure & Risk, Chemistry, Ecological Effects - Environmental Exposure & Risk, chemical mixtures, Chemistry and Materials Science, Ecological Risk Assessment, Ecology and Ecosystems, Biology, Ecological Indicators, biomarkers, chlorinated hydrocarbons, PCB, atmospheric transport, DDT, Lake Tahoe

Progress and Final Reports:

1996 Progress 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