PFAS compounds also were detected — though at lower levels — in the plasma of the popular gamefish in three other locations: the South Branch of the Potomac in West Virginia and at two sites in the Susquehanna River in Pennsylvania.

PFAS are a group of more than 4,700 chemicals that have been used for decades in a wide variety of products, including nonstick cookware, stain– and water-repellant fabrics and fire-fighting foams. They are very persistent — hence their nickname — and have been found across the United States in groundwater and surface water, in fish and other foods, as well as in people’s bodies.

The extent of PFAS contamination reported in the six-state Chesapeake Bay watershed has been fairly limited — about 20 sites, many of them connected with military bases or airports where fire-fighting foam has been sprayed. But testing to date also has been limited, though Pennsylvania and Maryland are expanding their search for the compounds in drinking water supplies.