Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS)
PFOA and PFOS are fluorinated organic chemicals that are part of a larger group of chemicals referred to as per- and poly-fluoroalkyl substances (PFASs). PFOS and PFOA have been extensively produced and studied in the United States. These manmade substances have been synthesized for water and lipid resistance. They have been used extensively in consumer products such as carpets, clothing, fabrics for furniture, paper packaging for food, and other materials (e.g., cookware) designed to be waterproof, stain-resistant or non-stick. In addition, they have been used in fire-retarding foam and various industrial processes.
People are exposed to PFOS and PFOA through food, food packaging, consumer products, house dust, and drinking water. Exposure through drinking water has become an increasing concern due to the tendency of PFASs to accumulate in groundwater. Such contamination is typically localized and associated with a specific facility, for example, an industrial facility where these chemicals were manufacture or used in other products, or airfield which used the chemicals for firefighting. Between 2000 and 2002, PFOS was voluntarily phased out of production in the U.S. by its primary manufacturer. Beginning in 2006 other manufacturers began to voluntarily limit the number of ongoing uses.
Since these chemicals have been used in an array of consumer products, scientists have found PFOA and PFOS in the blood of nearly all people tested. According to the Center for Disease Control (CDC), blood levels of both PFOS and PFOA have steadily decreased in U.S. residents since 1999-2000.
In May 2016, the United States Environmental Protection Agency (U.S. EPA) issued a lifetime health advisory for PFOS and PFOA for drinking water, advising municipalities that they should notify their customers of the presence of levels over 70 parts per trillion in community water supplies. U. S. EPA recommended that the notification of customers include information on the increased risk to health, especially for susceptible populations. Based on the current available peer-reviewed studies on laboratory animals and epidemiological evidence in human populations, the U.S. EPA released the following statement:
“These studies indicate that exposure to PFOA and PFOS over certain levels may result in adverse health effects, including developmental effects to fetuses during pregnancy or to breastfed infants (e.g., low birth weight, accelerated puberty, skeletal variations), cancer (e.g., testicular, kidney), liver effects (e.g., tissue damage), immune effects (e.g., antibody production and immunity), thyroid effects and other effects (e.g., cholesterol changes).”
Health and Safety Code section 116271 delegates to the Division of Drinking Water’s (DDW) Deputy Director the authority “to take action pursuant to Article 5,” including the power to issue a notification level (NL) pursuant to Health and Safety Code section 116455.
In response to a request from DDW, the Office of Environmental Health Hazard Assessment (OEHHA) recommended interim NLs for PFOA (based on liver toxicity, as well as cancer risks) and for PFOS (based on immunotoxicity). OEHHA made these recommendations following its review of currently available health-based advisories and standards and supporting documentation. After independent review of the available information on the risks, DDW established NLs at concentrations 13 parts per trillion for PFOS and 14 parts per trillion for PFOA. These levels are consistent with OEHHA’s recommendations.
Certain requirements and recommendations apply to a water system if it serves customers drinking water containing a contaminant greater than its notification level. In addition to notification levels and pursuant to Health and Safety Code section 116455, DDW has established a single response level for PFOS and PFOA based on U.S. EPA’s conclusion that the lifetime health advisory is applicable to both short-term and chronic risk assessment scenarios. The health advisory level offers a margin of protection for all persons throughout their life from adverse health effects resulting from exposure to PFOA and PFOS in drinking water and suggests that parents of formula-fed infants may consider the use of an alternative drinking water source or using formula that does not require adding water. The response level for PFOA and PFOS is a total concentration of 70 ppt for both contaminants, which is approximately five (5) times the individual notification level. When possible, DDW recommends removing the source from service or providing treatment when the concentration exceeds the level.
Once OEHHA issue its final recommendations for NLs for the two compounds, DDW will consider whether revisions to the NLs are appropriate.
Analytical Methods and Reporting
During the third Unregulated Contaminant Monitoring Rule (UCMR3), USEPA required laboratories to use EPA Method 537 to analyze for six perfluorinated compounds. At that time, the minimum reporting levels established by USEPA for PFOS and PFOA were 0.04 μg/L and 0.02 μg/L, respectively.
The minimum reporting level is similar to the detection limit for purposes of reporting, (DLR), which is established in regulation for chemicals with maximum contaminant levels. The DLR is the level at which the DDW is confident about quantification being reported.
DDW has identified EPA Method 537 Rev. 1.1. as a validated analytical method for detecting perfluorinated compounds in drinking water. This method is capable of detecting the following 14 perfluorinated compounds:
|C2801||PERFLUOROBUTANE SULFONIC ACID||PFBS|
|C2803||PERFLUOROHEXANE SULFONIC ACID||PFHxS|
|C2805||PERFLUOROOCTYL SULFONIC ACID||PFOS|
|C2807||N-ETHYL PERFLUOROOCTANESULFONAMIDOACETIC ACID||NEtFOSAA|
|C2808||N-METHYL PERFLUOROOCTANESULFONAMIDOACETIC ACID||NMeFOSAA|
DDW has also recently identified EPA Method 537.1 as a validated analytical method for detecting perfluorinated compounds in drinking water. This method is capable of detecting 18 perfluorinated compounds, which include all of the analytes detected by EPA Method 537 Rev 1.1 as well as the following four additional analytes:
|C2815||HEXAFLUOROPROPYLENE OXIDE DIMER ACID||HFPO-DA|
|C2816||9-CHLOROHEXADECAFLUORO-3-OXANONE-1 SULFONIC ACID||9Cl-PF3ONS|
Findings in California Drinking Water
From 2013 to 2015,UCMR3 required all large water systems (i.e., water systems serving over 10,000 people) to collect and analyze more than12,000 drinking water samples for PFOS and PFOA. In addition, some water systems serving less than 10,000 people reported approximately 400 drinking water results for PFOS and PFOA. This occurrence data identified 36 sources with PFOS detections and 32 sources with PFOA detections.
Drinking water systems are not currently required by state regulations to monitor for PFOA and/or PFOS. Nevertheless, because of concerns about possible contamination, some water systems have voluntarily chosen to sample their supplies for PFOA and PFOS.
The occurrence data for UCMR3 can be accessed at: https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule. A summary of the findings for California is available here.
California Environmental Contaminant Biomonitoring Program, 2015, Potential Designated Chemicals: Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) (PDF), State of California, March.
Centers for Disease Control and Prevention (CDC, 2009). Fourth National Report on Human Exposure to Environmental Chemicals. U.S. Department of Health and Human Services. (PDF)
US EPA, 2014. Emerging Contaminants – Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) (PDF), US Environmental Protection Agency, March.
US EPA, 2016. Drinking Water Health Advisory for Perfluorooctane Sulfonate (PFOS), May. (PDF)
US EPA, 2016. Drinking Water Health Advisory for Perfluorooctanoic Acid (PFOA), May. (PDF)
US EPA, 2016. FACT SHEET:PFOA & PFOS Drinking Water Health Advisories (PDF), US Environmental Protection Agency, November.
US Federal Register, 2016. Lifetime Health Advisories and Health Effects Support Documents for Perfluorooctanoic Acid and Perfluorooctane Sulfonate. 81 Fed. Reg. 101, May 25, 2016. (PDF)