An oily sheen shimmered along the Virginia side of the Potomac River this month. (Dean Naujoks / Potomac River Keeper)

If you’re in search of some locally sourced fish, be selective about what you choose to consume from the Potomac River.

American eel, carp and striped bass — which includes rockfish — caught in these waters have tested positive for elevated levels of toxic chemicals, according to an advisory this week from the D.C. Department of Energy and Environment.