Earlier this month, the Wisconsin State Natural Resources Board (NRB) moved to regulate the two most widely studied PFAS compounds, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), in both drinking water and surface water within the state. Unlike some other states that have moved to adopt aggressive standards for groundwater such as Michigan, however, the Board declined to set limits on PFAS in groundwater. The Wisconsin Board’s decisions come in the context of broader federal PFAS regulation by the United States Environmental Protection Agency (EPA), which recently submitted its proposal to the Office of Management and Budget to designate PFOA and PFAS as hazardous substances under the federal Comprehensive Environmental Response, Compensation & Liability Act (CERCLA). You can read more about the proposed designation here.
Groundwater Rule Rejected
The NRB rejected a rule to establish limits on PFAS compounds in groundwater after a 3-3 vote that included one abstention. The failed rule proposed standards for 17 total substances, including PFOA and PFOS, the two most regulated PFAS compounds. The proposed preventative action limit for PFOA and PFOS was 2 nanograms per liter, which translates to about 2 parts per trillion (ppt), while the enforcement standard proposed was 20 ppt. The standard was denied due to concerns over the economic impact of the proposed limits.
Drinking Water
The NRB passed a rule setting limits for two PFAS compounds, PFAS and PFOA for drinking water from municipal water systems. The final limit was set at 70 parts per trillion (ppt), which marked an increase from the Wisconsin Department of Health Services’ recommendation of 20 ppt. The 70 ppt standard is in line with EPA’s current health advisory level, a non-enforceable guidance value, of 70 ppt issued by EPA. However, EPA is currently developing enforceable drinking water standards for PFOA and PFOS, and the standard may become more stringent following the Science Advisory Board’s review of new scientific data on PFOA and PFOS.
Surface Water
The Board also approved a rule setting limits on PFOA and PFOS compounds in surface water. The standard for PFOS was set at a low 8 ppt for all waters “except those that cannot naturally support fish and do not have downstream waters that support fish” because of concern over the compound’s presence in fish tissues and resulting fish consumption advisories. The Board adopted a 20 ppt limit for PFOA in waters classified as public water supplies and 95 ppt for all other surface waters.
As a consequence of the surface water limitations, the rule allows the WDNR to use its wastewater discharge permitting processes to compel sources of PFOA and PFOS to restrict their PFAS discharges to surface waters.
The approved standards for surface and groundwater still require approval from Wisconsin Governor Tony Evers and the state legislature. Evers is likely to quickly approve the standards, but the Legislature is divided on whether to approve state level PFAS standards.