Chemical contaminants persist across Chesapeake Bay watershed

Chemical contaminants continue to afflict the Chesapeake Bay watershed, raising concern over water quality and the health of fish, wildlife and watershed residents.

Close to three-quarters of the Bay’s tidal waters are considered impaired by chemical contaminants, from the pesticides applied to farmland and lawns to repel weeds and insects to the household and personal-care products that enter the environment through our landfills and wastewater. But so-called “PCBs” and mercury are particularly problematic in the region, according to a report released last week by the U.S. Environmental Protection Agency (EPA), U.S. Geological Survey (USGS) and U.S. Fish and Wildlife Service (USFWS).

Both PCBs—short for “polychlorinated biphenyls”—and mercury are considered “widespread” in extent and severity, concentrating in sediment and in fish tissue and leading to fish-consumption advisories in a number of rivers and streams.

The District of Columbia, for instance, has issued such advisories for all of its water bodies, asking the public not to consume catfish, carp or eels, which are bottom-feeding fish that can accumulate chemicals in their bodies. While the District’s Anacostia and Potomac rivers raise the greatest concern in the watershed when it comes to fish tissue contamination, a November report confirmed that many Anacostia anglers are sharing and consuming potentially contaminated fish, sparking interest in reshaping public outreach to better address clean water, food security and human health in the area.

While PCBs have not been produced in the United States since a 1977 ban, the chemicals continue to enter the environment through accidental leaks, improper disposal and “legacy deposits”; mercury can find its way into the atmosphere through coal combustion, waste incineration and metal processing.

Exposure to both of these contaminants can affect the survival, growth and reproduction of fish and wildlife.

The Chesapeake Bay Program will use this report to consider whether reducing the input of toxic contaminants to the Bay should be one of its new goals.

Read more about the extent and severity of toxic contaminants in the Bay and its watershed.