Impact of regulatory actions to establish maximum contaminant levels on per- and polyfluoroalkyl substances in New Jersey public water systems.

BACKGROUND

The U.S. Environmental Protection Agency set drinking water Maximum Contaminant Levels (MCLs) for several PFAS in 2024, yet few evaluations of earlier state regulations have been conducted. We evaluated the impact of regulatory actions taken by the New Jersey Department of Environmental Protection (NJDEP) to set PFAS drinking water standards in NJ community water systems (CWS).

METHODS

The NJDEP performed statewide testing of CWS PFAS levels in 2006 and 2009-2010, which were supplemented by additional CWS data reported to NJDEP and federal monitoring from 2013 to 2015 using methods including EPA method 537 and 537.1. The NJ Drinking Water Quality Institute formally recommended MCLs to NJDEP for PFNA (13 ng/L) in July 2015, for PFOA (14 ng/L) in March 2017, and PFOS (13 ng/L) in June 2018. Routine CWS monitoring began in 2019, covering the study period of 2006-2025. Quarterly PFOA, PFOS, and PFNA testing results were obtained from 47 CWS with monitoring data before and after the MCL recommendations. Using linear regression, we fit interrupted time series models to estimate the change and trend in PFAS levels following proposed MCLs.

RESULTS

We obtained 4,150, 4,086, and 4,053 monitoring results for PFOA, PFOS, and PFNA, respectively. We observed declines in the proportion of PFOA (49.3% v s 14.9%), PFOS (11.6% vs 3.5%), and PFNA (23.6% vs 1.5%) results above the MCL following recommendation of PFAS regulations (chi-squared P < 0.001). There was a 55% (95% CI: 11%, 77%) and 50% (95% CI: 14%, 71%) decline in PFOA and PFNA levels, respectively, following recommendation of MCLs. There were declines in quarterly trend in PFOS (2%, 95% CI: 0%, 5%) and PFNA levels (6%, 95% CI: 2%, 9%).

DISCUSSION: Regulated PFAS levels declined following formal recommendation of MCLs to NJDEP. Actions taken toward establishing regulations to limit drinking water PFAS exposures can achieve substantial reductions.