Science Center Objects

The objective of the South River Mercury TMDL study is to develop a better understanding of methyl mercury cycling in the South River and calculate mercury loading reductions that would protect fish from high mercury concentrations.

Problem

The South River and South Fork Shenandoah River are scenic recreational streams, but they are contaminated with mercury. The mercury contamination stretches from Waynesboro for 125 miles downstream to Front Royal. A major source of the mercury is known to be a former DuPont facility in Waynesboro that disposed mercury waste from 1929 to 1950. Regulatory actions dealing with the streams have focused on the health threat to people who eat mercury contaminated fish.

The VADEQ regularly samples fish to monitor concentrations of mercury in fish. In 2002, smallmouth bass had mercury concentrations as high as 4 ppm and average concentrations of 1.3 ppm. These numbers are higher than the state mandated maximum allowable mercury concentrations in fish of 0.5 ppm. Because of this, the Virginia Department of Health has placed a fish consumption advisory on the South River and South Fork Shenandoah River.

Ongoing Studies

The US Environmental Protection Agency (EPA) has required Virginia to develop plans for cleaning polluted streams (those on the 303d list) in the state. This TMDL study will form the foundation used to develop a cleanup plan for the South River and South Fork Shenandoah River. 

The Virginia DEQ samples fish every year and is scheduled to do a comprehensive sediment survey in 2007.

DuPont sponsors numerous studies of the mercury problem through a group known as the South River Science Team (SRST). The South River Science Team consists of scientists and representatives from government agencies, universities, environmental non-profit groups and Dupont. The group meets regularly to share scientific findings and plan future studies. Studies currently being performed by SRST members include investigations of mercury occurrence in stream water, groundwater, surface runoff, soil, plants, fish, algae, earthworms, and birds.

In July, 2005, Dupont signed an agreement with the Natural Resources Defense Council and the Virginia Chapter of the Sierra Club that requires Dupont to perform a large six-year ecosystem study of the South River watershed. Click here for a Description of the Study (pdf file, 113 Kb) or the legal Consent Decree (pdf file, 1.1 Mb).

The objective of the South River Mercury TMDL study is to develop a better understanding of methyl mercury cycling in the South River and calculate mercury loading reductions that would protect fish from high mercury concentrations.

Approach

Data will be collected to calculate fluxes of mercury and methyl-mercury in the watershed. Four monitoring stations, operated jointly by the VDEQ and the USGS, continuously measure stream discharge and/or water quality in the South River. These stations are at Waynesboro (01626000), South Dooms (01626850), Dooms (01626920), and Harriston (01627500). Water samples are periodically sampled to measure mercury and methyl-mercury concentrations along with a suite of related water-quality parameters. The data collection will continue for 2 years.

The data will then be used to calculate mercury fluxes and to build a model of mercury cycling in the river. From this model, reductions in mercury loading required to lower fish tissue mercury concentrations to safe levels will be calculated.

Relevance and Benefits

Work on this project will develop a foundation for the future remediation of the South River and South Fork Shenandoah River. Basic science benefits will come from a better understanding of methyl-mercury cycling in fresh water systemsthat is developed by this project. A better understanding of the regional aquatic ecosystem will also result from the collection and analysis of water quality data during this project.

Additional Resources

PRESENTATION TO THE SOUTH RIVER SCIENCE TEAM: JUNE 2005

STREAMFLOW DATA: SOUTH RIVER NEAR WAYNESBORO, VIRGINIA

STREAMFLOW DATA: SOUTH RIVER NEAR DOOMS, VIRGINIA

STREAMFLOW DATA: SOUTH RIVER AT HARRISTON, VIRGINIA

WATER QUALITY DATA: SOUTH RIVER NEAR WAYNESBORO, VIRGINIA

WATER QUALITY DATA: SOUTH RIVER NEAR DOOMS, VIRGINIA

WATER QUALITY DATA: SOUTH RIVER AT HARRISTON, VIRGINIA

USGS NATIONAL MERCURY RESEARCH: ACTIVE SOUTH RIVER DATA STATIONS

USGS NATIONAL MERCURY RESEARCH: GENERAL INFORMATION

VIRGINIA DEPARTMENT OF ENVIRONMENTAL QUALITY: MERCURY INFORMATION

VIRGINIA DEPARTMENT OF ENVIRONMENTAL QUALITY: VIRGINIA STREAMS TMDLS

VIRGINIA DEPARTMENT OF HEALTH: SOUTH RIVER FISHING ADVISORIES

US ENVIRONMENTAL PROTECTION AGENCY: CLEANUP REPORT: DUPONT FACILITY IN WAYNESBORO, VIRGINIA

US ENVIRONMENTAL PROTECTION AGENCY: MERCURY INFORMATION

SOUTH RIVER SCIENCE TEAM (SRST) ABSTRACT

DUPONT AND NATURAL RESOURCES DEFENSE COUNCIL (NRDC) SETTLEMENT: DESCRIPTION OF STUDY

DUPONT AND NATURAL RESOURCES DEFENSE COUNCIL (NRDC) SETTLEMENT: CONSENT DECREE