MassDEP proposed groundwater cleanup standards for PFAS significantly lower than the federal health advisory as part of its long-expected proposed revisions to Massachusetts’ regulations governing the assessment and cleanup of contaminated properties. The proposed revisions to the Massachusetts Contingency Plan (MCP) became available on MassDEP’s web site on April 18, 2019, and include a series of important changes upon which we will report in the coming days. Interested parties may comment on any of the proposed MCP changes through July 19, 2019. In addition, five public hearings will be held in different locations across the state in May 2019.

States have led the effort to regulate PFAS compounds – per and polyfluoroalkyl substances consisting of several thousand man-made, inert substances. Most of the discussion nationwide regarding PFAS has focused on two specific compounds:

  1. Perfluorooctane sulfonate (PFOS).
  2. Perfluorooctanoic acid (PFOA).

That discussion is evolving and now often includes four additional PFAS compounds:

  1. Perfluorodecanoic acid (PFDA).
  2. Perfluoroheptanoic acid (PFHpA).
  3. Perfluorohexanesulfonic acid (PFHxS).
  4. Perfluorononanoic acid (PFNA).

The MassDEP has proposed to issue standards for these six PFAS compounds.

Reportable Concentrations

The proposed MCP revisions would set reportable concentrations for the six PFAS compounds for groundwater and soil, which trigger an obligation to report the release to the state. The proposed standards are:

  GW-1 Possible Drinking Water Areas GW-2 All Other Groundwater S-1 More Accessible Soil

S-2 Other Soils

Combined total of:

  • PFOA
  • PFOS
  • PFDA
  • PFHxS
  • PFNA
  • PFHpA
0.00007 mg/L See individual  components below. See individual compounds below. See individual compounds below.
PFOA See above. 40 mg/L 0.0002 mg/kg 0.4 mg/kg
PFOS See above. 0.5 mg/L 0.0002 mg/kg 0.4 mg/kg
PFDA See above. 40 mg/L 0.0002 mg/kg 0.4 mg/kg
PFHxS See above. 0.5 mg/L 0.0002 mg/kg 0.4 mg/kg
PFNA See above. 40 mg/L 0.0002 mg/kg 0.4 mg/kg
PFHpA See above. 40 mg/L 0.0002 mg/kg 0.4 mg/kg

Groundwater Cleanup Standards

The proposed MCP revisions would set “Method 1” cleanup standards for the six PFAS compounds for groundwater. Method 1 standards can be used at most sites by comparing exposure point concentrations to the standard. The proposed rule would set the following standards:

  GW-1 Applies to Potential Drinking Water Areas GW-2 Applies to Areas Near Structures GW-3 Applies to All  Groundwater in MA

Combined total of:

  • PFOA
  • PFOS
  • PFDA
  • PFHxS
  • PFNA
  • PFHpA
0.02 parts per billion (ppb) See individual compounds below. See individual compounds below.
PFOA See above. N/A 40,000 ppb
PFOS See above. N/A 500 ppb
PFDA See above. N/A 40,000 ppb
PFHxS See above. N/A 500 ppb
PFNA See above. N/A 40,000 ppb
PFHpA See above. N/A 40,000 ppb

Soil Cleanup Standards

The proposed MCP revisions would also set Method 1 cleanup standards for the six PFAS compounds for soil. The standards differentiate between soil that is more accessible to people (e.g., S-1) and soil that is less accessible (e.g., S-3), and take into account potential impacts to groundwater. We provide below the proposed standards for the most accessible soils, S-1:

  S-1 Soil in Areas That Are GW-1 S-1 Soil in Areas That Are GW-2 S-1 Soil in Areas That Are GW-3

Combined total of:

  • PFOA
  • PFOS
  • PFDA
  • PFHxS
  • PFNA
  • PFHpA
0.0002 parts per million (ppm) See individual compounds below. See individual compounds below.
PFOA See above. 0.3 ppm 0.3 ppm
PFOS See above. 0.3 ppm 0.3 ppm
PFDA See above. 0.3 ppm 0.3 ppm
PFHxS See above. 0.3 ppm 0.3 ppm
PFNA See above. 0.3 ppm 0.3 ppm
PFHpA See above. 0.3 ppm 0.3 ppm

These proposed revisions to the MCP do not address drinking water standards. However, MassDEP has indicated that it is working on a Maximum Contaminant Level for drinking water with the goal of issuing proposed regulations by the end of the year. However, this week MassDEP has sent letters to public water suppliers with levels above 20 parts per trillion (ppt) for the combined PFAS compounds, encouraging them to expeditiously lower the concentration of these PFAS compounds to below 20 ppt.