DEVELOPMENT OF A TOTAL MAXIMUM DAILY LOAD FOR MERCURY IN THESAVANNAH RIVER BASIN

摘要

A lawsuit was brought against Region IV of the United States Environmental Protection Agencyrn(EPA-IV) by the Sierra Club and others when EPA-IV and the State of Georgia failed to writernTotal Maximum Daily Loads (TMDLs) for Georgia in a timely manner. The lawsuit resulted in arnconsent decree that required EPA-IV to write TMDLs for Georgia on a specific timeline. One ofrnthe TMDLs EPA-IV developed was for mercury in the Savannah River Basin (SRB). The SRBrnruns southeast to the Atlantic Ocean and is bordered by both Georgia and South Carolina.rnAlthough SRB waters do not exceed aquatic life water quality criteria for mercury, existing fishrnadvisories for mercury were considered by EPA-IV to be a violation of Georgia’s “fishable”rnnarrative standard, thus requiring inclusion of the SRB in Georgia’s 303(d) list of impairedrnwaters under the Clean Water Act. EPA-IV issued a proposed target concentration for mercury inrnthe SRB of 1 part per trillion (ppt, also designated as nanograms per liter, or ng/l) in Februaryrn2000. A lengthy period of discussion with stakeholders resulted in site-specific research by EPArnand a more palatable final TMDL. The final TMDL gives affected dischargers the option ofrnmeeting end-of-pipe limits for mercury of 2.8 ppt or implementing a mercury minimization plan.