Massachusetts Finalizes PFAS Cleanup Standards for Groundwater, Soil & Proposes an MCL

December 20, 2019

On December 13, the Massachusetts Department of Environmental Protection (MassDEP) filed a final rule for groundwater and soil cleanup standards of certain per- and polyfluoroalkyl substances (PFAS) under the Massachusetts Contingency Plan (MCP).  Under the new rule, six PFAS compounds are listed as hazardous substances: perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), and perfluorodecanoic acid (PFDA). MassDEP also filed for a draft drinking water standard that proposes a maximum contaminant level (MCL) and establishes monitoring and analytical requirements for the six listed PFAS.

The new groundwater and soil cleanup standards, to be promulgated and finalized on December 27, 2019, are as low as 20 ng/L in groundwater (as the sum of all six listed PFAS) and 0.3 to 2 µg/kg in soil, depending on the listed PFAS compound. The standards also vary depending on the groundwater and soil classification as defined by the MCP. Parties determined to be responsible for contamination will be required to remediate to these standards.

The proposed drinking water MCL is 20 ng/L for the sum of the six listed PFAS, which would regulate more individual PFAS compounds than any other state. MassDEP also proposes that laboratory analysis would be performed using either EPA Method 537 or 537.1. Initial monitoring of listed PFAS would be required with four consecutive quarterly samples collected the first month of every quarter. Routine monitoring would be required depending on whether any listed PFAS was detected in the initial monitoring. Municipalities serving more than 50,000 individuals would start monitoring in April 2020. Suppliers serving 10,000 to 50,000 individuals would start in October 2020, and those serving 10,000 individuals or fewer would start in April 2021.

How Exponent Can Help

Exponent's expert consultants in regulatory compliance, contaminant fate and transport, and analytical chemistry help clients navigate the current regulatory landscape and manage their ongoing environmental liabilities. Our multidisciplinary team of scientists and engineers considers both state and federal regulations when developing strategic solutions for our clients. Exponent can help with selecting appropriate methods and laboratories for PFAS analyses based on the intended use of the data, and Exponent's scientists and engineers can assist with source identification, chemical fingerprinting, and fate and transport analyses of PFAS in the environment. Exponent can also assist with reviewing and commenting upon proposed state and federal regulations for the PFAS compounds.