The Potomac River estuary extends for 117 miles (188 km) from its mouth at Pt. Lookout on the Maryland side and Smith Point on the Virginia side, to its head-of-tide located approximately 0.4 miles (0.64 km) upstream of Chain Bridge in the District of Columbia. In the document, “Potomac River at Chain Bridge,” or simply “Chain Bridge,” is used to indicate the Potomac River estuary head-of-tide. The surface area of all tidal waters, including Potomac River embayments and the tidal Anacostia River, is about 434 mi2 (1,125 km2 ).
A consent decree was entered into by the EPA and the U.S. District Court (Kingman Park Civic Association, et al. v. U.S. Environmental Protection Agency, et al, No. 1:98CV00758 (D.D.C.)) that requires the District of Columbia to complete a polychlorinated biphenyls (PCB) Total Maximum Daily Load (TMDL) by September 30, 2007. Maryland and Virginia were not required to complete their PCB TMDLs by this date, but the three jurisdictions informally agreed in 2004 to coordinate their PCB TMDL development efforts and address all of their tidal Potomac PCB impairments by that date. This study is the result of that agreement. A joint TMDL was desirable because the impaired waterbodies in the three jurisdictions are in such close proximity to each other that flows and loads cross state lines in each direction. Furthermore, a single, joint TMDL would be more cost effective, and the jurisdictions would avoid confusing the public with three independent TMDLs completed on different dates using potentially different models and assumptions, and possibly reaching different conclusions, particularly with respect to PCB loads crossing state lines. The provisions of this PCB TMDL are severable. If any provision of the PCB TMDL, or the application of any provision of this TMDL to any circumstances or participating jurisdiction, is held invalid by a court of competent jurisdiction, the application of such provision to other circumstances and any other participating jurisdiction, and the remainder of the TMDL document available below, shall not be affected.
The State of Maryland has listed the Potomac River Lower Tidal (basin number 02140101), Potomac River Middle Tidal (basin number 02140102), Potomac River Upper Tidal (basin number 02140201), and tidal portion of the Anacostia River (basin number 02140205) as impaired due to elevated levels of PCBs in fish tissue and other causes (MDE 2006). These waters are designated Use II: Support of Estuarine and Marine Aquatic Life and Shellfish Harvesting. The Maryland Department of the Environment identified the waters of the Potomac River Lower Tidal watershed on the State’s 303(d) List as impaired by nutrients (1996), sediments (1996), toxics (PCBs in fish tissue) (2002), bacteria (2004), and impacts to biological communities (2004 and 2006) (MDE 2006). A TMDL for Fecal Coliform to address the 2004 bacteria listing was approved by the EPA in 2005. The Department listed waters of the Potomac River Middle Tidal watershed as impaired by nutrients (1996), sediments (1996), toxics (PCBs in fish tissue) (2002), metals (cadmium, chromium, copper, and lead) (1996), and impacts to biological communities (2004 and 2006) (MDE 2006). A Water Quality Analysis (WQA) for cadmium, chromium, copper, and lead to address the 1996 metals listing was approved by the EPA in 2006. Waters of the Potomac River Upper Tidal watershed were placed on the State’s 303(d) List as impaired by nutrients (1996), sediments (1996), toxics (PCBs in fish tissue) (2002), metals (copper) (1996), and impacts to biological communities (2006 – non-tidal) (MDE 2006). A WQA for copper to address the 1996 metals listing was approved by the EPA in 2006. The waters of the tidal Anacostia River watershed were placed on the State’s 303(d) List as impaired by nutrients (1996), sediments (1996), toxics (PCBs in fish tissue) (2006), bacteria (2004), and trash/debris (2006). A TMDL for fecal coliform to address the 2004 bacteria listing was approved by the EPA in 2006, and a TMDL for sediments to address the 1996 listing was approved by EPA in 2007.
The document below establishes TMDLs for PCBs for 28 listed impaired water body segments in the tidal waters of the Potomac and Anacostia Rivers in the District of Columbia, Maryland, and Virginia.
Total Maximum Daily Loads of Polychlorinated Biphenyls (PCBs) for Tidal Portions of the Potomac and Anacostia Rivers in the District of Columbia, Maryland, and Virginia(Approved on October 31, 2007)
Comment Response Document
Please direct questions or comments concerning this project to Maryland's TMDL Program at (410) 537-3818.
1800 Washington Boulevard, Baltimore, MD 21230