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 (PPT) 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).”

Notification Level

Notification levels are nonregulatory, health-based advisory levels established for contaminants in drinking water for which maximum contaminant levels have not been established. Notification levels are established as precautionary measures for contaminants that may be considered candidates for establishment of maximum contaminant levels but have not yet undergone or completed the regulatory standard setting process prescribed for the development of maximum contaminant levels and are not drinking water standards.

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. Assembly Bill 756 (codified as Health and Safety Code section 116378) provides for new reporting and notification requirements for detections of perfluoroalkyl substances and polyfluoroalkyl substances (collectively, PFAS).

In August 2019, after further review, the Office of Environmental Health Hazard Assessment (OEHHA) recommended NLs for PFOA and for PFOS be set at the lowest levels at which they can be reliably detected in drinking water using currently available and appropriate technologies. This recommendation is based on OEHHA’s development of reference levels intended to protect against cancer and noncancer effects, including effects on the liver and immune system. These recommendations supersede the recommended interim NLs that OEHHA provided to SWRCB in July 2018. After independent review of the available information on the risks, DDW established NLs at 6.5 PPT for PFOS and 5.1 PPT for PFOA. These levels are consistent with OEHHA’s recommendations.

A response level (RL) is set higher than a notification level and represents a recommended chemical concentration level at which water systems consider taking a water source out of service or provide treatment if that option is available to them. Starting in January 2020, water systems that receive an order and detect levels of PFAS substances that exceed their response level, shall take a water source out of use, treat the water delivered, or provide public notification.

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 lowered the response levels for PFOA and PFOS from 70 PPT combined to 10 PPT for PFOA and 40 PPT for PFOS based on a running four quarter average.

At the request of the Division of Drinking Water, OEHHA is initiating the development of Public Health Goals (PHGs) for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in drinking water. PHGs are concentrations of contaminants in drinking water that pose no significant acute or chronic health risks. OEHHA establishes PHGs, which are used as the health basis for the development of California’s primary drinking water standards (Maximum Contaminant Levels or MCLs).

Through the State Water Board’s investigation, seven additional PFAS chemicals have been detected in multiple wells in California. The State Water Board has requested OEHHA’s recommendation in developing notification levels for the following chemicals:

  • perfluorohexane sulfonic acid (PFHxS)
  • perfluorobutane sulfonic acid (PFBS)
  • perfluorohexanoic acid (PFHxA)
  • perfluoroheptanoic acid (PFHpA)
  • perfluorononanoic acid (PFNA)
  • perfluorodecanoic acid (PFDA)
  • 4,8-dioxia-3H-perflourononanoic acid (ADONA)

As additional PFAS data become available, DDW may request from OEHHA to include additional PFAS chemicals. The State Water Board also requested that OEHHA include an evaluation of whether some of the PFAS chemicals should be grouped together when being considered in a regulatory manor and if it is possible to consider them in subclasses based on specific characteristics or features of the chemicals.

For more information regarding the impact of Assembly Bill 756 (as codified as Health and Safety Code section 116378) on public water systems, please refer to the Frequently Asked Questions: AB 756 Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS).

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 537.1 as a validated analytical method for detecting perfluorinated compounds in drinking water. This method is capable of detecting the following 18 perfluorinated compounds:


STORET Code CHEMICAL Abbreviation
C2801 PERFLUOROBUTANE SULFONIC ACID PFBS
C2802 PERFLUOROHEPTANOIC ACID PFHpA
C2803 PERFLUOROHEXANE SULFONIC ACID PFHxS
C2804 PERFLUORONONANOIC ACID PFNA
C2805 PERFLUOROOCTYL SULFONIC ACID PFOS
C2806 PERFLUOROOCTANOIC ACID PFOA
C2807 N-ETHYL PERFLUOROOCTANESULFONAMIDOACETIC ACID NEtFOSAA
C2808 N-METHYL PERFLUOROOCTANESULFONAMIDOACETIC ACID NMeFOSAA
C2809 PERFLUORODECANOIC ACID PFDA
C2810 PERFLUORODODECANOIC ACID PFDoA
C2811 PERFLUOROHEXANOIC ACID PFHxA
C2812 PERFLUOROTETRADECANOIC ACID PFTA
C2813 PERFLUOROTRIDECANOIC ACID PFTrDA
C2814 PERFLUOROUNDECANOIC ACID PFUnA
C2815 HEXAFLUOROPROPYLENE OXIDE DIMER ACID HFPO-DA
C2816 9-CHLOROHEXADECAFLUORO-3-OXANONE-1 SULFONIC ACID 9Cl-PF3ONS
C2817 11-CHLOROEICOSAFLUORO-3-OXAUNDECANE-1-SULFONIC ACID 11Cl-PF3OUdS
C2818 4,8-DIOXA-3H-PERFLUORONONANOIC ACID ADONA

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.

Resources

Fact Sheet: Update on Spring 2019 State Water Board Directives for Soil and Water Samples at Likely Per- and Poly-Fluoroalkyl Substance (PFAS) “Hot Spot” Locations (08/23/19)

Fact Sheet: Frequently Asked Questions: Drinking Water Guidelines for PFOA and PFOS (08/23/19)

Frequently Asked Questions: Per- and Poly-fluoroalkyl Substances (PFAS)Water Monitoring

Example PFOA/PFOS Notification Letter: (PDF) (Word)

Laboratories Accredited to Analyze for PFAs in Drinking Water by EPA Method 537 Revision 1.1 or EPA Method 537.1

Drinking Water Sample Collection for PER and POLYFLUORINATED ALKYL SUBSTANCES (PFAS) Sampling Guidance

Primary Changes in the Revised April 2019 PFAS Sampling Guidance

PFAS Water Systems Orders - April 30, 2019

PFAS Phased Investigation Approach Presentation Training for Public Water Systems (Recording) - April 3, 2019

PFAS Phased Investigation Approach Presentation for Public Water Systems (Slides) – April 3, 2019

References

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)

  (Page last updated 04/23/2020)

 
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