2000 Progress Report: Sacramento River Watershed

EPA Grant Number: R825433C002
Subproject: this is subproject number 002 , 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: Sacramento River Watershed
Investigators: Hinton, David E. , Botsford, Louis , Fan, Teresa W-M. , Fry, D. Michael , Higashi, Richard M. , Lasley, Bill L. , Orlob, Gerald , Wilson, Barry W.
Institution: University of California - Davis
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1996 through September 30, 2000
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
RFA: Exploratory Environmental Research Centers (1992) RFA Text |  Recipients Lists
Research Category: Center for Ecological Health Research , Targeted Research


The overall goal of this research is to determine adverse effects of multiple stressors on tissues, cells and macromolecules of fish, crayfish and fish-eating birds within a waterway and to incorporate these findings into hydrodynamic and biologically-based models enabling better understanding of the role of multiple stressors in population level responses. The overall result should enable ecologically-based management and a reduction in stressors.

Progress Summary:

The Sacramento River watershed is stressed by diversion of river flows, historical mining of copper, zinc and mercury, and agricultural and urban chemical runoff, including the recent redirection of saline drainage waters that contain selenium into the delta (Figure A-1). The combined stresses have led to deterioration in both surface and ground water quality creating an increasing concern about the impact of agricultural practices on terrestrial wildlife. The potential interaction of these stressors on the river, coupled with over-fishing, introduced species, and direct mortality from pumping juvenile fish into aqueducts, have driven several species of fish to near extinction. Populations of clams also show effects of pollutants in the upper San Francisco Bay. Historic contamination by heavy metals is now exacerbated by organophosphate pesticides at levels exceeding National Academy of Sciences recommendations, throughout the lower watershed and San Francisco Bay.

Figure A-1.

Figure A-1. Sacramento River Watershed, Showing Multiple Stresses and Ecosystem Processes

This project combines terrestrial and aquatic ecosystem studies to better meet Center objectives. By placing greater importance on studying the mechanisms of multiple stressor toxicity, the scope of this project now extends from the molecular and cellular levels, to diminished fecundity of individuals, leading to the decline of populations and loss of biodiversity at community and ecosystem levels. A valuable feature of the Center is its emphasis on comparative studies. In some instances, common mechanisms of action are being discovered in birds, fish, and rodents, enhancing our ability to interpret findings throughout the ecosystem.

Critical questions include: (a) which molecular, cellular, and organismal test systems best reveal effects of the stressors in each of the species of concern (b) which tests best indicate whether effects of multiple stressors are additive, antagonistic, or synergistic (c) which mechanisms link levels of biological organization, and (d) how might these affect targets of future investigative processes?

The Sacramento River watershed encompasses an area of 66,000 square kilometers. Surrounded by high mountains of the Sierras and Cascades to the east and Coastal Range to the west, this watershed includes a complex system of reservoirs that supply water to the agricultural areas of the central valley, and the urban areas of Southern California. From mountains and foothills to the north and east, the river flows through the Central Valley and, below the City of Sacramento, forms a large delta which receives inflow from the San Joaquin River. Orchards are abundant in the foothills and higher reaches of the valley, rice and other crops are major recipients of river water for irrigation. Large agricultural tracts and islands with abundant stone-fruit orchards are located in the delta which is continuous to the west with the San Francisco Bay.

Figure A-2.

Figure A-2. Management Considerations

The management of the watershed is complex, and Figure A-2 illustrates the more important considerations. Multiple uses of the watershed have led to many ecosystem stresses resulting in concern by federal, state and local managers and a fundamental reassessment of land and water use.

Selection of field sites for Center activities has been based on existing toxicity data from mine drainage and agricultural return water inputs which have resulted in demonstrated ecosystem deterioration. Our rationale for selection of representative terrestrial study areas includes sites that have established runoff data from field experiments, and known bioaccumulation of specific inorganic and organic toxicants with demonstrated acute toxicity to test species of cladocerans and fish. Agricultural sites include orchards where dormant sprays are applied in the winter rainy season and the small Willow Slough watershed in Yolo County where surveys of birds and mammals are being conducted. Nest boxes have also been established and are monitored for kestrels and tree swallows to evaluate the habitat changes brought by agriculture to wildlife.

A complex data set has been collected in the first years of Center activities. We focused on stressors, including contaminants in sediments and water, agricultural chemical transfer to wildlife, and runoff inputs into agricultural drains and the river. The contaminant levels in populations of finfish and birds continue to be measured (Analytical and Biomarkers Core), and the distributions of larval stages of fish, and models of pollutant and larval fish movements through the system are now being integrated (Hinton and Orlob with assistance from Data Analysis and Decision Support Core). New methods, including use of solid phase micro extraction (SPME), are being developed through the Analytical and Biomarkers Core and used to measure contaminants in sediment invertebrates (crayfish and clams) and to link pollutants in real time by monitoring phytoplankton populations.

Results from Center studies identified data gaps, enabling us to develop plans to better integrate the data sets, fill gaps in the framework of the watershed model, and provide integration on specific chemical, physiological, histopathological, and ecological questions. The latter used biomarkers developed by the Analytical and Biomarkers Core. Each of the seven subprojects in the Sacramento River Watershed has specific plans to fill information gaps in the ecological processes diagram (Figure A-1). A number of projects (A.1 through A.6 -Hinton, Washburn, Fan, Higashi, Fry, Lasley and Wilson) involving birds, rodents, finfish, shellfish and crayfish are designed to determine bioeffects (see bottom right of Figure A-1).

Suborganismal studies, strongly supported by the Analytical and Biomarkers Core, investigate molecular through physiological phenomena and these levels of biological organization reflect changes over a time of minutes to days or weeks. If physiological alterations are protracted, the individual may show histopathological alterations, or reduced bioenergetics or inhibition of reproductive processes. These intermediate level changes may take weeks to months to detect. If the intermediate level responses are severe, population level effects may be seen. These could take months to years to occur and further illustrate the need for long-term data sets in ecotoxicologic investigations. Finally, the Sacramento River Watershed projects and the analytical chemical and biomarker core interactions focus on investigations at the molecular level and extend up to the level of populations. These include reproduction of birds and mammals, development of birds and fish, application of biomarkers to field situations, biochemical indicators, bioavailability, and liver pathology. Through the integrative efforts of the Data Integration and Decision Support and Transport and Fate Cores, processes are now being modeled which extend our combined effort to the community, landscape and region.

Certain subprojects will become involved in metals effects (A.1 through A.6), particularly mercury-selenium interactions and toxicity mechanisms to invertebrates, fish, and bioaccumulation through aquatic insects to birds. We will address how the interaction of metals and chemical species occurring in the ecosystem modify the bioavailability of these toxicants. Salinity intrusion into the delta, and effects on plankton and larval fish will be assessed directly with toxicity tests, and included in the river model.

Several innovative analytical chemical methods (Higashi with help from Analytical and Biomarkers Core) will be evaluated on continuing projects and newly initiated projects, including NMR studies (Fan and Hinton assisted by Higashi) of fish embryos exposed to metabolic and neurotransmitter toxicants (Wilson to direct) at critical stages in development. Data will be input into the model for fish exposure to agricultural drain water. SPME sampling methods (Higashi) will be used to evaluate sediment toxicants, water toxicants, and biotransfer of toxicants in the food web. New high pressure liquid chromatography (HPLC) methods (Higashi) will evaluate carotenoids and other pigments as measures of exposure of phytoplankton to agricultural toxicants, to monitor phytoplankton community structure and provide improved data for input into the ecological models (Quinn and Jassby of the Data Integration and Decision Support Core) of the river and delta.

The data on trophic transfer of pollutants (Fry and Hinton, assisted by Analytical and Biomarkers Core; Higashi in conjunction with Quinn and Jassby) through organisms (phytoplankton, aquatic insects, fish, and birds), will provide greater integration of the terrestrial studies into the watershed project, especially with the inclusion of studies of tree swallows and blackbirds living along agricultural drain water canals, where exposure to pesticides and selenium secondarily through aquatic insects occurs (Fry with assistance of Wilson). The discovery that Kestrels in Yolo County have high levels of selenium has prompted new studies of both selenium and mercury exposure to Kestrels in agricultural areas where historic deposition of mercury by winter flooding of farmlands has occurred.

Future Activities:

Future studies will also emphasize effects on birds living along agricultural drains. These will focus on bioaccumulation of metals and of endocrine disruptive pesticides (dicofol, endosulfan, lindane, alkylphenols as mixing agents for agricultural chemicals). Laboratory models will be used for egg injections, chick exposures, and determination of the critical periods in development where agricultural chemical exposure will have a developmental impact.

The role of bioavailability and relationship to meaningful estimates of pollutant fate and transport is a major future goal. Seasonal riverine processes which may influence bioavailability will be assessed and used to better predict biologically relevant aspects of fate and transport.

Supplemental Keywords:

RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Water, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Water & Watershed, Environmental Chemistry, wildlife, Aquatic Ecosystem, Environmental Microbiology, Terrestrial Ecosystems, Biochemistry, Ecology and Ecosystems, Watersheds, Mercury, anthropogenic stress, population stressors, contaminant exposure, fish, fish habitat, watershed, watershed management, Sacramento River, agricultural watershed, marine biology, agricultural watersheds, fish communities, fish-eating birds, marine biogeochemistry, bioassays, crayfish, aquatic ecosystems, birds, environmental stress, ecosystem stress, ecological research

Progress and Final Reports:

Original Abstract
  • 1997
  • 1998
  • 1999
  • Final

  • 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