Grantee Research Project Results

1999 Progress 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
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
RFA: Exploratory Environmental Research Centers (1992) RFA Text |  Recipients Lists
Research Category: Center for Ecological Health Research , Targeted Research

Objective:

To study the bioaccumulation of organochlorines in the fish and amphibian communities of the Sierra Nevada waterbodies.

Progress Summary:

Atmospheric transport of toxic compounds provides a potential source of these pollutants to regions which are otherwise not directly impacted. In this section of our research, we 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 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 PCBs, p, p-DDE and toxaphene. Since 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 is the likely significant source of input not only to Lake Tahoe but other Sierra Nevada subalpine and alpine lakes. Similar atmospheric processes which transport nitrogen and organochlorine chemicals into the Sierra Nevada may also 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. 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 northwest to southeast carry those chemicals. The rising air masses are known to release most of their moisture as precipitation on the western face of the mountains in winter. 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 the 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. We have analyzed rainbow trout samples collected from various locations from Sierra Nevada. We found that samples from remote, high altitude lakes have much lesser amounts of PCB residues as compared to those from low altitudes. Also there appear to be some pockets of clean areas on the eastern slope of high mountain peaks and ranges. PCB residues are particularly high in Lake Tahoe and Huntington Lake (a comparison or reference site to Lake Tahoe on the western slope.) The residue levels of toxaphene showed less altitude-dependent differences in distribution. The manuscript describing the details of the patterns of residues of organochlorine chemicals has been accepted for publication.

We have investigated the bioaccumulation of PCBs and toxaphene in Pacific Treefrogs (Hyla regilla) from the range. H. regilla tadpoles were collected throughout the Sierra Nevada and analyzed for the presence of polychlorinated biphenyls (PCBs, as Aroclor 1260) and toxaphene. Whole tadpole PCB levels ranged from 44 ppb (wet weight) at lower elevations on the Western slope to 1.5 ppb high on the Eastern slope, while toxaphene levels ranged from 10.7 ppb to 1.5 ppb. Straight-line regression of PCB and toxaphene residue levels versus elevation yielded an inverse relationship with an r-squared value of 0.74 (PCB, n=18), and 0.70 (toxaphene, n=15) indicating a significant elevation effect on PCB and toxaphene bioaccumulation in these tadpoles. A comparison of mean PCB residue values from populations at 2000 to 6500 feet versus those collected at 7000 to 11500 feet indicated significantly different means (p<0.05, n=23). A comparison of tadpole samples from sites in East-facing (n=7) versus West-facing (n=14) drainage basins also showed significant differences in PCB residue levels (p<0.001), suggesting the possibility of a rain-shadow effect in the long-range atmospheric transport of PCBs to the Sierra Nevada mountains. We have prepared a manuscript of this work to be submitted to Environmental Toxicology and Chemistry. Another area we have been investigating relates to the effects of PCBs on the leopard frog (Rana pipiens), which serves as a surrogate for the threatened indigenous Sierra Nevada mountain yellow-legged frog (Rana muscosa). R. muscosa exists at high elevations (from 5,000-12,000 feet) in the Sierras, and has been declining dramatically within the last 20 years for unknown reasons. In order to investigate the possibility of PCB-mediated immunosuppression and cold tolerance modulation in Ranid frogs, the effect of 5 mg/kg intraperitoneal PCB (as Aroclor 1260) treatment on liver glucose transporter (GLUT2) titers, liver glycogen stores, and selected indicators of immune function was assessed in R. pipiens under room temperature and cold acclimation conditions. Hepatic GLUT2 titers were significantly elevated by cold treatment within the vehicle control groups. PCB treatment also resulted in a significant increase in GLUT2 titers among ambient temperature groups, possibly similar to the enhancing effect of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) on glucose uptake in guinea pig liver. Among cold-treated groups, PCB treatment resulted in a six-fold decrease in GLUT2 titers. Cold treatment significantly depressed liver glycogen in both PCB and control groups. PCB treatment did not significantly affect hepatic glycogen content among either cold-treated or ambient temperature groups, but did increase the magnitude of the depression from the ambient temperature group to the cold-treated group. Among the cold treatments, neutrophils increased significantly in number from control to PCB treatment, while basophils increased significantly upon PCB treatment among the ambient temperature groups. PCB treatment resulted in nearly a 10-fold decrease in serum complement activity in both ambient temperature and cold-treated groups. The ability of Aroclor 1260 to mimic the effect of cold exposure is significant, as it demonstrates that PCBs can induce immunosuppression in Ranids to an extent commensurate with the effects of natural stressors. This work is being prepared for submission to Aquatic Toxicology.

Future Activities:

We have developed an XAD-resin based method for water concentration. We plan to sample water throughout the Sierra Nevada, particularly in Yosemite National Park, and analyze for PCBs, DDT, toxaphene, and if possible, chlordane in order to study possible correlations between residue levels found in Hyla regilla and the degree of water contamination in these lakes and ponds. We also plan to continue our biochemical work on the possible adverse effects of PCBs on overwintering mechanisms in Rana pipiens. We are particularly interested in the changing levels of glycogen storage and the decreased levels of glucose transporter proteins in muscle and adipose tissue.

Supplemental Keywords:

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

Progress and Final Reports:

Original Abstract

1997

1998

Final 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