NHDES Report on PFAS MCL/AGQS Development

The summary report on the NHDES development of the Maximum Contaminant Levels and Ambient Groundwater Quality Standards for perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononoic acid (PFNA) and perfluorohexanesulfonic acid (PFHxS) is available here: https://www.des.nh.gov/organization/commissioner/pip/publications/documents/r-wd-19-01.pdf

The report provides the method by which NHDES derived the proposed Maximum Contaminant Levels (MCLs) and Ambient Groundwater Quality Standards (AGQSS) for four perflourinated componds, as authorized by the legislature in 2018 (SB309). These proposed standards were derived following a review of the draft ATSDR MRLs (note MRLs are not the same as MCLs), the 2016 EPA Health Advisories for PFOA and PFOS, toxicity values identified by other states and recent scientific studies. Many of which were recommended by the public during technical workshops. While the Legislature requested NHDES to document and consider the occurrence of these chemicals in New Hampshire, the viability of detection and treatment technologies, as well as the costs and benefits to affected parties as a result of setting the standards, the proposed standards have not been modified away from the health-based standards due to these other considerations. As such, the proposed standards address long-term, chronic exposure and were derived to be fully protective for the most sensitive populations through life, including the earliest stages of life, based on the science and studies that are available today. The NHDES Risk Assessment Team continues to review emerging research to identify information that would necessitate re-assessment of the proposed standards as described further in the report.