The march toward regulation of PFAS in Pennsylvania continues (see our recent post on statewide public water system sampling results), with the release of final data from sampling conducted in September 2019 of surface waters throughout the Commonwealth.  The study, a collaboration among the U.S. Geological Service (“USGS”), the Susquehanna River Basin Commission, and the Pennsylvania Department of Environmental Protection (“PADEP”), collected and analyzed over 200 grab samples collected from 178 PADEP Water Quality Network station locations, as well as passive samples collected at 18 locations over a period of about one month.  The results reflect raw surface water concentrations for a set of 33 PFAS chemicals, including PFOA, PFOS, and PFBS, plus 19 oxidizable PFAS precursors.

According to the sampling results, Total PFOS+PFOA generally fell within a range of non-detect to 34 parts per trillion (“ppt”) in grab samples; for comparison’s sake, the U.S. EPA’s current health advisory level, or HAL, for Total PFOS+PFOA in drinking water is 70 ppt.  One passive sample, collected at a location in Neshaminy Creek, exceeded the EPA drinking water HAL for PFOA+PFOS, coming in at 212 ppt.

In its summary of the results, PADEP notes distinctions between its raw surface water sampling analysis and analysis in finished drinking water (aside from the fact that finished drinking water has had some treatment to remove contaminants, PADEP points out that the lab analytical method for PFAS differs for raw surface water and drinking water).  However, the agency’s summary also posits that the results illustrate the sensitivity of the passive sampling method and its ability to detect chemicals that grab sample analysis might miss.

Stay tuned for more, as results from follow-up monthly sampling are still to come. But the identification of the presence of various PFAS chemicals in surface waters throughout Pennsylvania, even at levels below the EPA’s HAL, could be another line of evidence that PADEP relies upon to support the development of PFAS regulatory standards in multiple media.