Pennsylvania’s new “Safe Drinking Water PFAS MCL Rule” became effective on January 14, 2023, upon the publication of the new regulations in the Pennsylvania Bulletin.  As discussed in a previous post, this rulemaking establishes new safe drinking water maximum contaminant levels (“MCLs”) for perfluorooctanoic acid (“PFOA”) and perfluorooctane sulfonic acid (“PFOS”) of 14 ng/L and 18 ng/L, respectively, under the Pennsylvania Safe Drinking Water Act regulations at 25 Pa. Code Chapter 109.  The new regulations will also, among other things, establish monitoring, sampling and analytical requirements, and acceptable treatment technologies for achieving compliance with the MCLs.

Importantly, the new MCLs also establish new medium-specific concentrations (“MSCs”) for PFOA and PFOS in groundwater under the Pennsylvania Land Recycling and Environmental Remediation Standards (“Act 2”) Chapter 250 regulations.  Prior to finalization of this new rule, the Act 2 groundwater standards for PFOA and PFOS were 70 parts per trillion (“ppt”).  As a result, we expect that more Pennsylvania sites seeking Act 2 clearance for groundwater impacts will need to investigate for, and likely remediate, PFOA and PFOS in groundwater. 

[View source.]