U S. Environmental Pnxidien Agaric1/
                                         Watershed
                                    Field  Research
Public concern has grown over the past 30 years regarding the
health of our ecological resources and the contamination of
water supplies by sediments, chemicals (e.g., pesticides,
fertilizer nitrates and phosphates), metals, and pathogens (e.g.,
fecal coliforms, E.coli, and enterococci). Contaminants are
transported from their site of application to nearby streams and
lakes via the atmosphere, storm runoff, and sub-surface flow,
including ground water. The U.S. EPA conducts field research
to collect environmental data that describes contaminant
release, movement, and related exposures.  These data are used I
to assess existing conditions and to develop and field test
mathematical models for use in predicting future conditions and Stream sampling with cableway
in evaluating alternative management and restoration           system.
approaches.

An Integrated Watershed Research Approach: The integration of field research and model
development in the study of watershed-scale ecological exposure is a prime focus for scientists at
the Ecosystems Research Division (ERD) of the U.S.  EPA Office of Research and Development's
National Exposure Research Laboratory. Scientists collect data for use in the development and
field testing of multimedia exposure models. These models simulate the relationship between
contaminant release; its fate and transport through air, soil, and water; and the degree of exposure
to humans, fish, and wildlife. To be meaningful, results must be gathered for at least three years to
account for variables such as seasonal weather  patterns. Site location, site characteristics,
cropping patterns, application rates, and other variables are selected to enable a better
understanding of the relationship between cause and effect for the measured contaminants.

Scientists from the ERD and the EPA Region 4 Water Management Division and Science and
Ecosystem Support Division are collaborating to collect field data in the South Fork Broad River
Watershed of the Savannah River Basin, Georgia. Field research is now underway in this
watershed to simultaneously measure contaminants and their impacts on ecological health. Data
obtained from this project will be used to develop and test models and to develop protocols for
calculating the Total Maximum Daily Load (TMDL) of bedload (sediment that is transported along
the streambed), suspended  sediments, nutrients (e.g., nitrate, ammonia, and phosphorus), and
pathogens in the watershed. A TMDL is an estimate of the maximum pollutant loading from point
and nonpoint sources that receiving waters can accept without exceeding water quality standards.

-------
                        Watershed Field Research
Benefits:
      The data obtained through the field research is used to provide improved field assessment
       methodologies and monitoring protocols and is widely used for field testing models.
      The data can be used for planning purposes by EPA regional offices, program offices,
       local government agencies, and the general public.
Purpose:
      This research supports the Agency's Sound Science and Clean Water goals by providing an
       improved understanding of environmental risks.
Accomplishments:
      Fourteen field studies have been conducted at various locations over a thirty year period.
      Comprehensive databases have been developed on the transport of pesticides and nutrients
       and on the leaching of pesticides into ground water.
      Field monitoring protocols have been developed for contaminant runoff and leaching.
      Sample requirements have been estimated for pesticide leaching.
      Pesticide and nitrate concentrations have been compared from on-farm drinking water
       wells and research monitoring wells.
Participants:
      The U.S. Environmental Protection Agency, Office of Research and Development, National
       Exposure Research Laboratory, Ecosystems Research Division and the EPA Region 4
       Water Management Division and Science and Ecosystem Support Division.
      Other Federal Agencies, States, and landowners.
                                For More Information
                                        Contact:
                                      Charlie Smith
                                   smith.charlie(g),epa. gov
     National Exposure
    Research Laboratory
Ecosystems Research Division
         Website
  http://www.epa. gov/athens
       For more information about this and other NERL science projects, visit our Website
                                http ://www. epa.gov/nerl/
WEBSITE ANNOUNCEMENT                                                  October 2002

-------