Urban Waters Federal Partnership—Patapsco Watershed (Baltimore, Md. region)
Reductions in PCBs Mandated for Baltimore’s Tidal Waters
USGS pilot study to provide guidance
Science Center Objects
Several watersheds in the Baltimore region have elevated PCB loads in tidal waters. Local jurisdictions are responsible for reducing PCB loading from their watersheds. The USGS is embarking on a pilot study in the Patapsco watershed that will help determine sources of PCBs and will demonstrate innovative monitoring and analysis techniques for more efficient use of mitigation resouces.
Industrial chemicals known as polychlorinated biphenyls (PCBs) are legacy pollutants—they persist in the environment long after their use has been banned. This group of carcinogenic chemicals was banned in 1979 but continue to contribute to contamination of Chesapeake Bay. Researchers from the USGS and the University of Maryland Baltimore County (UMBC) are focusing on PCBs in tributaries to the Back River to better understand the contamination. The Patapsco watershed will serve as a pilot study to refine approaches to determining PCB sources and to apply innovative sampling and analysis techniques.
The Back River, along with several other Chesapeake Bay waterways, has been classified as PCB-impaired by the U.S. Environmental Protection Agency. A Total Maximum Daily Load (TMDL), which identifies the maximum amount of a pollutant that a water body can receive while still maintaining water-quality standards, mandates a reduction in PCBs loads in these waterways.
In the initial phase of the pilot study, the USGS has inventoried existing data and discharge permits, identified potential locations for sample collection, and compiled that information into a Geographic Information System (GIS) platform. Field reconnaissance has aided in refining location of sampling sites. USGS and UMBC are investigating three general sources: 1) mobile sediment-bound PCBs under low-flow and stormflow conditions, 2) stationary sediment-bound PCBs in "hot spots", and 3) PCBs in wastewater, including effluent and sanitary sewer overflows. Sampling has begun and will continue through 2020.
The results of pilot study could aid in eventual cleanup efforts in other urban areas in the region and around the country.
The project is being done in cooperation with Baltimore City, Baltimore County and UMBC.