PFAS Overview

The purpose of this webpage is to provide the ASTSWMO membership with information on Perfluoroalkyl and polyfluoroalkyl substances (PFASs), also known as perfluorinated chemicals (PFASs), which are emerging contaminants of concern. The identification and cleanup of these contaminants may pose unique challenges in State cleanup programs.

There are many chemicals that fall into the generic family of PFASs. This page will predominantly focus on the two most commonly researched PFASs:

  • perfluorooctanioc acid (PFOA)
  • perfluorooctane sulfonate (PFOS)
PFASs have been used to make fluoropolymer coatings and products that are widely used by consumers due to their oil and water repellent characteristics. They have also been used to make surfactants that are used in fire-fighting foams and mist suppressants for metal plating operations. Locations that may have been contaminated with PFASs include:
  • firefighting training areas,
  • aircraft crash sites,
  • metal coating and plating facilities,
  • water treatment systems and receiving water bodies, and
  • airport hangars and other facilities storing fire-fighting foams
The scientific community, industry leaders, regulatory agencies, and others are working to fully understand the health and environmental effects of PFASs as well as developing various analytical methods, treatment technologies, and remediation alternatives. In addition, federal government agencies and States are developing their own regulatory guidelines and protocols for addressing PFASs contamination in the United States. This page includes introductory information and resources specific to PFASs and their persistence in the environment, and summarizes policy decisions and programs being implemented by State and Federal agencies.




For more info on PFAS, please read the PFOA and PFOS Information paper developed by the ASTSWMO Federal Facilities Research Center:

Please read this FactSheet released by the EPA for an overview on PFOS/ PFOA.

Please read this State Resources Table created by the ASTSWMO Federal Facilities Subcommittee.



ENVIRONMENTAL FATE AND TRANSPORT

PFOS and PFOA compounds are highly soluble in water and typically present as an anion (conjugate base) in solution and have very low volatility due to their ionic nature. Long chain PFASs have low vapor pressure, and aquatic environments are expected to be their primary sink in the environment. These compounds do not readily degrade by most natural processes. They are thermally, chemically, and biologically stable and are resistant to biodegradation, atmospheric photooxidation, direct photolysis, and hydrolysis. The structure of PFASs increase their resistance to degradation: the carbon-fluorine bonds require a lot of energy to break, and the fluorine atoms shield the carbon backbone.

PFASs have been found worldwide in soil, groundwater, surface water, rain, ice caps, air, plants, animal tissue, and blood serum. The highest concentrations found in the environment tend to be associated with direct discharge from industries where PFASs are in use. Fresh waters in the vicinity of these industries have been documented to have concentrations of PFASs ranging from 1 – 1000s parts per trillion (ppt). Oceanic concentrations of PFASs are several orders of magnitude lower, ranging closer to 0.01 – 0.1 ppt. Interestingly, while not volatile, PFASs have been detected in air, sediments, and fauna in the Arctic, despite being geographically separated from any possible human sources .

PFASs are mobile in soil and leach into groundwater. It is not completely understood how the compounds are transported to areas far removed from industrial facilities or consumer products. Three hypotheses have been presented regarding the method of long-range transport of PFASs. One possibility is direct ocean transport of PFASs. The second is that PFASs are transported directly as marine aerosols, which is supported by evidence that surfactants accumulate at the surface of water bodies. In addition, a third hypothesis is that volatile fluorotelomer alcohols travel great distances in the atmosphere and degrade into PFOS and PFOA.



HEALTH AND ENVIRONMENTAL EFFECTS

Due to the wide variety of uses of PFASs, it is not difficult to understand how people are exposed to these chemicals. In the 1990s, regulatory agencies called for additional research on PFASs when it was discovered that these substances were found throughout the earth’s environment and were also very commonly found in human blood serum. Research has indicated that humans can be exposed to PFASs through the following routes:

a) Occupational exposure. Levels of PFASs in the blood of people who work where PFASs are manufactured or used are much higher than people from the same area that do not work where PFASs are manufactured or used. Inhalation and dermal contact are the most common exposure entry routes.

b) Non-occupational exposure. PFASs contamination of food and air is likely to be responsible for most non-occupational exposures in industrial nations. Potential exposure routes include:

i. Eating fish from contaminated water bodies;
ii. Eating crops grown in contaminated soils, particularly in agricultural areas that receive amendments of biosolids from wastewater treatment plants (WWTPs). Biosolids from WWTPs become contaminated from the treatment of contaminated wastewaters at the WWTP.
iii. Infant consumption of contaminated breast milk. Breast milk can become contaminated from PFASs in the bloodstream of the mother;
iv. Drinking contaminated water.
v. Inhalation of contaminated air;
vi. Inhalation and ingestion of house dust containing PFASs; and
vii. Direct contact with consumer products that have been treated with PFASs (such as carpets which are treated with PFASs for stain resistance) or which contain residuals from a manufacturing process. Children especially may ingest PFASs through hand-to-mouth transfer from treated carpets.



ANALYTICAL AND TREATMENT METHODS

The unique chemical and physical properties of PFOA and PFOS prevent them from being measured using conventional analysis. For example, their extremely low volatility eliminates the possibility of using gas chromatography/mass spectrometry (GC/MS). As a result, the more complex methodology of liquid chromatography and tandem mass spectrometry (LC/MS-MS) has been proven most reliable for analyzing PFOS and PFOA in biological and environmental samples. This type of analysis has allowed for more sensitive determination of many PFASs, including PFOA and PFOS, in air, water, and soil.

U.S. EPA developed the first reference method for PFASs in drinking water in September 2008. EPA’s Method 537, Version 1.1 was published in September 2009, and is intended for analyzing selected PFASs in drinking water using solid phase extraction with LC/MS-MS. The method has been validated for 14 different perfluorinated alkyl acids and has lowest concentration minimum reporting limits of 2.9 ppt to 14 ppt. Before September 2009, there were no validated test methods or standardized data quality criteria. As a result, most PFC data generated and used in earlier publications was not based on validated methods and therefore cannot be used for comparison with today’s data.

Many reports have been published on the analysis of PFASs in surface waters, but very few report on the contents of PFASs in air or drinking water. Methods for surface water analysis are similar to those used for drinking water analysis. The European Food Safety Authority and ATSDR have compiled and summarized the various analytical technologies available for detecting various PFASs. ASTM has published two methods for analyzing PFASs in environmental media, D7968 – 14 for soil and D7979 – 15 for water, sludge, influent, effluent and wastewater, but neither has been validated yet. Some environmental laboratories have also developed their own LC/MS-MS procedures allowing for the detection of PFASs.The unique chemical and physical properties of PFASs make the use of conventional treatment technologies difficult. For groundwater, the most common treatment is extraction and filtration through granular activated carbon (GAC). This technology has been shown to consistently remove PFOS at µg/L concentrations with an efficiency of 90%; however, it is not as efficient at removing PFOA and other PFASs. Other adsorbents that have been utilized include: powdered activated carbon, polymers, maize-straw-derived ash, alumina, and montmorillonite. Alternative treatment technologies for groundwater include ion exchange, sonochemical treatment and reverse osmosis for groundwater. All of these technologies still require groundwater extraction and exsitu treatment and are more costly than GAC and relatively experimental.

For soil treatment, contaminated soils are usually removed and sent to landfills. Not only is this an expensive remediation alternative it is also inefficient because the contaminants are not destroyed, but just transferred to another location. PFAS contaminated soils can also be incinerated, but only high temperature incinerators will completely destroy PFOS and PFOA.

Studies continue to be conducted to find more efficient, less costly, in-situ treatment technologies.

PFOS/PFOA Work Group Members

The workgroup is composed of six Board Members and two ASTSWMO Staff.

REFERENCES

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Darwin, R. L. (2011). Estimated inventory of PFOS-based Aqueous Film Forming Foam (AFFF), 2011 update to the 2004 report entitled “Estimated Quantities of Aqueous Film Forming Foam (AFFF) In The United States”. Prepared for the Fire Fighting Foam Coalition, Inc., Arlington, VA.

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