The U.S. Environmental Protection Agency (EPA) has just issued a lifetime drinking water health advisory standard of 0.07 micrograms per liter (µg/L) or 0.07 parts per billion (ppb) for the Perfluoroalkyl substances (PFAS) perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) based on a reference dose (RfD) derived from a developmental toxicity study in mice.(1,2) In the recently published Drinking Water Health Advisories for PFOA and PFOS, the EPA found there is suggestive evidence of carcinogenic potential for PFOA and PFOS under EPA’s Guidelines for Carcinogen Risk Assessment. (1,2,3)

The nonregulatory Health Advisory (HA) Program, established by EPA in 1978, provides informal technical guidance to public health officials (and other interested groups) to assist administrators (federal, state, and local) and managers of public/community water systems in protecting public health. HAs identify the concentration of a contaminant in drinking water at which adverse health effects are not anticipated to occur over specific exposure durations (e.g., 1 day, 10 days, a lifetime). (1,2) In addition, HAs identify treatment technologies and procedures used to mitigate short-term contamination incidents or emergency spills that can affect drinking water quality, but are not regulated under the Safe Drinking Water Act (SDWA).(1,2) Currently, the EPA lists HAs for more than 200 contaminants.

Presently, there are no federal regulations under the SDWA or national recommended ambient water quality criteria under the Clean Water Act (CWA) for PFOA or PFOS. In January 2009, EPA developed provisional HAs in drinking water for PFOA (0.4 micrograms per liter (µg/L)) and PFOS (0.2 micrograms per liter (µg/L)). (1, 2) The provisional HAs were developed to reflect an amount of PFOA/PFOS that could cause adverse health effects in the short term (weeks to months). (1,2) The provisional HA was intended as a guideline for public water systems (PWS) while allowing time for EPA to develop a lifetime HA (published in May 2016). (1,2)

Perfluoroalkyl substances (which include PFOA and PFOS) have been widely found in consumer and industrial products, as well as in food items. (1) In the United States, PFOA was used in carpets, leathers, textiles, upholstering, paper packaging, and coating additives as a waterproofing or stain-resistant agent.(1) In addition, PFOA and/or PFOS is used to increase the fire resistance of aviation fluids. (1,2) While major U.S. manufacturers have voluntarily agreed to phase out production of PFOA by the end of 2015 and the only major U.S. manufacturer of PFOS voluntarily agreed to phase out production of PFOS in 2002, PFOA and PFOS are very persistent in the environment and the human body. (1,2)

Exposure to PFOA/PFOS remains possible due to its legacy uses, existing and legacy uses on imported goods, degradation of precursors, and extremely high persistence in the environment and the human body. (1,2) Currently, the dominant source of human exposure to PFOA and PFOS is expected to be from the diet. (1,2) In addition, indoor dust (from carpets, textiles, etc.) is of particular concern for exposure of PFOA/PFOS to children. Lastly, PFOA and PFOS are known to be transmitted to the fetus in cord blood and to the newborn in breast milk. (1,2)

Water resources contaminated by PFOA/PFOS have been associated with releases from manufacturing sites, industrial sites, fire/crash training areas, and industrial or municipal waste sites where products are disposed of or applied. (1,2)

According to the EPA’s most recent data on unregulated drinking water contaminants, released in January, 14 drinking water systems around the country reported levels of PFOA that exceed the new HA threshold, while 40 reported PFOS above the new HA threshold. (4,5)


Stewart McCollam, P.E. is an Environmental Engineer with the Smith Management Group. Stewart can be reached at


(1)        Drinking Water Health Advisory for Perfluorooctanoic Acid (PFOA). EPA Document Number: 822-R-16-005. Washington, DC: U.S. Environmental Protection Agency Office of Water Health and Ecological Criteria Division, 2016. Web.

(2)        Drinking Water Health Advisory for Perfluorooctane Sulfonate (PFOS). EPA Document Number: 822-R-16-004. Washington, DC: U.S. Environmental Protection Agency Office of Water Health and Ecological Criteria Division, 2016. Web.

(3)        Guidelines for Carcinogen Risk Assessment. EPA Document 630-P-03-001F. Washington, DC: U.S. Environmental Protection Agency, 2005. Web.

(4) PFOA Drinking Water Advisory