Four Pennsylvania agencies have issued a joint warning about fish caught in the Neshaminy Creek basin that winds through Bucks and Montgomery Counties:

• Department of Agriculture
• Department of Environmental Protection
• Department of Health
• Fish and Boat Commission

The ban resulted from evidence of extremely high levels of Perfluorooctane Sulfonate (PFOS), a chemical once used to repel stains as a fabric protector.

PFOS is one of a group of perfluoroalkyl and polyfluoroalkl chemical substances (PFAS) that readily bioaccumulates in fish tissue.

Chemical levels detected in fish from the Neshaminy Creek watershed had levels over the 0.2 parts per million, prompting the warning. It applies specifically to two Bucks County parks popular for water recreation: Neshaminy Creek State Park and Tyler State Park.

Scientists classify PFOS chemicals as emerging contaminants because the risks they pose to human health and the environment are not completely understood.

More on the dangers of fish from the Neshaminy Creek basin are at the Pennsylvania Department of Environmental Protection.