Checking drinking water for PFAS and lithium

Public water systems in the US would have to monitor their drinking water for the presence of 29 environmentally persistent synthetic compounds and of lithium under a proposal the Environmental Protection Agency released Feb. 22.

The 29 compounds are per- and polyfluoroalkyl substances (PFAS) that are either sulfonic or carboxylic acids, some with ether or sulfonamido groups (four examples shown). Exposure to a number of PFAS is linked to reproductive, developmental, liver, kidney, and immunological problems.

The alkali metal lithium occurs naturally in some groundwater, including brines pumped from oil and gas wells. Exposure to lithium can impair thyroid and kidney function.

About 45% of US public-supply water wells contain levels of lithium that potentially could pose a risk to human health, according to a US Geological Survey study released in February (Sci. Total Environ., 2021, DOI: 10.1016/j.scitotenv.2020.144691).

The EPA does not currently limit the amount of any PFAS or lithium in drinking water. However, the agency announced in January that it officially determined it needs to regulate two toxic PFAS that contaminate drinking water supplies across the US, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). Formerly used in fire-fighting foams, PFOA and PFOS are no longer manufactured in the US.

Under the EPA’s Safe Drinking Water Act proposal, utilities would monitor for the presence and amount of the 29 PFAS and lithium from Jan. 1, 2023, to Dec. 31, 2025, and report their findings to the agency. The EPA would then use the data to determine whether federal legal limits are needed on any of these substances in drinking water to protect public health. Congress could speed up the regulatory process by passing legislation requiring the EPA to set limits on the chemicals in drinking water.