At its July 29, 2021 meeting, the Pennsylvania Department of Environmental Protection (“Department”)’s Public Water System Technical Assistance Center (TAC) Board voted to recommend that the Department proceed with a draft proposed rulemaking to set maximum contaminant levels (MCLs) in drinking water for certain PFAS compounds.  The Department has proposed drinking water levels of 14 parts per trillion (ppt) for PFOA and 18 ppt for PFOS, which would put Pennsylvania roughly in the middle, in terms of stringency, of the states that have regulated those two compounds in drinking water.

In its presentation to the TAC Board, the Department recommended the MCLs for PFOA and PFOS and  outlined its analysis, which included derivation of a reference dose for all but one of the PFAS compounds at issue (PFHpA), evaluation of the recommendations of Drexel University’s Drexel PFAS Advisory Group as to maximum contaminant level goals (MCLG) for each PFAS substance, completion of a PFAS sampling plan to generate statewide occurrence data, and consideration of other factors required by federal and Pennsylvania law (including technical limitations such as available analytical methods and detection and reporting limits, treatability and available treatment technologies, and costs and benefits of the regulation).  The Department noted that it was not at this time proposing MCLs for other PFAS substances, namely PFNA, PFHxS, PFHpA, PFBS, and HFPO-DA, due to several factors: a lack of occurrence data above the MCLG, incomplete cost/benefit data and analysis, lack of evidence on toxicity (for PFHpA), and lack of treatability data (for HFPO-DA).

The TAC Board’s recommendation is another step on the long regulatory pathway toward Pennsylvania’s adoption of MCLs for PFOA and PFOS.  Stay tuned for more.