Predictability and Practicability of Attaining Pennsylvania’s Proposed MCLs for PFOS and PFOA in Groundwater
Level: Intermediate
Presenter
Jeffrey R. Hale, P.G.
Senior Principal Professional
Kleinfelder
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Level: Intermediate
Who should attend: This presentation will be of particular interest to consultants, regulators, and environmental managers interested in PFAS and contaminant hydrogeology.
Webinar Overview (updated 24 August): Pennsylvania has initiated rulemaking to establish maximum contaminant levels (MCLs) for the per and polyfluorinated alkyl substances PFOS (18 ng/L) and PFOA (14 ng/L). These values are intended to be health-protective, and are less stringent than U.S. EPA’s recently revised health advisory levels (HALs) of 0.02 ng/L and 0.004 ng/L for PFOS and PFOA, respectively. Other states (Michigan, New Hampshire, and New Jersey) have promulgate slightly more stringent criteria than those proosed for Pennsylvania.
These MCLs are intended to be health protective at the tap / point of use. However, the practicability of attaining these criteria in groundwater and the distance from source at which these regulatory criteria are attained without intervention have received little evaluation. The vast majority of PFAS mass in groundwater is represented by relatively few samples that are more than 10X the proposed MCLs for PFOS and PFOA. Conversely, relatively little mass of PFAS in groundwater corresponds to many samples with PFAS concentrations between the proposed Pennsylvania MCLs and 10X those MCLs. This results in long PFAS plumes relative to ng/L MCLs with little mass in the distal extent of the PFAS plume. Empirical fate & transport modeling using available data sources demonstrates expected distances to attainment of Pennsylvania’s proposed MCLs for PFOS and PFOA, as well as the sensitivity of that attainment distance to other state and federal regulatory criteria and guidance values.
About our presenter: Jeffrey R. Hale, PG is located in Pittsburgh, PA where he has been a Pennsylvania Professional Geologist since 2000. Jeff is a Senior Principal Professional at Kleinfelder. He provides consultation, strategy, and direction for challenging environmental and natural resources issues with emphasis on PFAS, emerging contaminants, complex sites, remediation, liability management, and environmental forensics.
