PFAS Sampling: Not Just Any Ordinary Sample

What you need to know before sampling for PFAS

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Andrew Mihailovsky/Dreamstime

For the past several years, programs and research studying Per- and polyfluoroalkyl substances (PFAS) have rapidly increased across the country. Although PFAS have been in use since the 1940s, public awareness of the environmental and health risks posed by PFAS began at the turn of the century. This increased public concern led to a voluntary phase out of perfluorooctanoic acid (PFOA) in all US manufacturing processes. However, PFOA is still used in manufacturing processes world-wide and is used to manufacture products imported into the US. Also, PFOA is only one type of PFAS chemical and there are many more PFAS chemicals in use. The Environmental Protection Agency (EPA) launched a stewardship program in 2006 to monitor these chemicals and to investigate their potential dangers. Research will continue over the coming years, and new articles are posted weekly about the topic. Staying aware of the latest information about PFAS will help when the time for new regulation measures comes to pass.

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What are PFAS?
PFAS is a family of chemicals that includes perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), Gen X chemicals (high-performance fluoropolymers that do not use PFOA), and more, that have become prevalent in the environment and in humans due to contamination from man-made, PFAS-containing products. Chemically, PFAS are thousands of synthetic chemicals made of a strong carbon backbone chain (C) with attached fluorine atoms (F). Their persistence in the environment and resistance to degradation is attributed to their C-F bonds, one of the strongest and shortest chemical bonds in nature.

This bond makes PFAS very useful in manufacturing processes because the chemicals do not easily break down and are long-lasting, but this persistence has negative environmental consequences. PFAS are now widely distributed across the planet and are highly persistent in groundwater, soil, air, and sediments. EPA has found that certain PFAS chains bioaccumulate in the blood and tissue of humans and other animals, posing a variety of health risks including cancer (EPA 2019). Exposure to PFAS can occur through water, food, and even dust particles. A study in Catalonia, Spain, found that, “dietary intake was the main exposure pathway to PFOS and PFOA, followed by the consumption of drinking water…dust and air (indoor environment) would mean only a minor contribution” (Ericson et al. 2012). Once PFAS enter the body, they bind to protein and can be found in the blood, kidneys, liver, or spleen. There is still much research to be done, but current research indicates that PFAS chemicals are potentially carcinogenic and may be linked with unhealthy cholesterol, thyroid disease, poor immune response, and reproductive problems. A recent research endeavor in 2019 found that serum PFAS were significantly associated with altered thyroid and kidney function in humans (Blake et al. 2018). The persistence of PFAS in the body are variable and depend on the chain length and structure of the PFAS chemical in question, but it is clear that some forms of PFAS pose a viable threat to human and environmental health.

PFAS chemicals are known to be harmful to human health, yet they are present in products used by most people every day. PFAS are present in sun blocks, hair products, cosmetics, fragrances, pre-packaged food, waterproof materials, clothing washed with fabric softeners, and much more. Due to the prevalence of PFAS in a variety of materials used daily, special precautions must be taken when sampling for PFAS to avoid sample contamination.

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Sampling Solutions
Low laboratory detection limits (parts per trillion, or nanograms per liter) and high potential for cross-contamination lead to an increased probability of false positives when sampling for PFAS relative to other substances. Stormwater or drinking water samples are particularly susceptible to cross-contamination because PFAS chemicals are often present in the materials used to sample the water itself, such as Teflon tubing, Teflon-coated sample seals, and polytetrafluoroethylene (PTFE) bottles (CSWRCB 2019). Due to their unique chemical structure and resistance to degradation, PFAS are used in the manufacturing of a variety of water-resistant consumer products including plastic bottles, plastic bags, waterproof pens and paper, waterproof clothing, and more. Oftentimes, many of these products are present during stormwater sample collection. Physical contact between a sample and these items at a sampling site could lead to PFAS contamination and/or false-positives. EPA recommends that a PFAS sampling program be designed and implemented for each project requiring PFAS sampling to avoid potential sources of contamination (EPA 2019). The California State Water Quality Control Board (CSWRCB) also recommends that a project-specific Quality Assurance Project Plan (QAPP) be developed (CSWRCB 2019). This QAPP should identify project goals, quality control measures, methods of analysis and analyte lists, reporting limits, data needs, and potential sources of cross-contamination. Some examples of cross-contamination sources specific to sampling methods are water used in drilling equipment, sampling equipment itself (especially Teflon-containing equipment), field clothing or PPE, food packaging, sun protection products, and contaminated soil, dust, or air from the surrounding environment. The CSWRCB recommends that all sampling supplies and materials be divided into three groups: allowable materials, staging area-only materials, and prohibited materials (CSWRCB 2019).

  1. Allowable materials are components proven to be PFAS-free and can be used at any time during the sampling stage.
  2. Staging area-only materials may contain PFAS and should never contact the sample directly but can be used in the staging area away from the sample itself.
  3. Prohibited materials are known to contain PFAS and should not be present at the sampling site or staging area at any time.

Many sunscreens and bug sprays are known to contain PFAS. California, along with other states, have developed useful sampling guidelines with information about which common branded materials can or cannot be present during sampling (CSWRCB 2019). However, if there is a material that would make sampling much easier but whether it poses a PFAS contamination risk is unknown, the best way to find out is to test it. Sending a sample of the material to a lab to determine whether there is a detectable presence of PFAS may add some cost and effort to a project, but it is often simpler and cheaper in the long run than altering the sampling process unnecessarily. However, if the material in question has been previously studied and found to contain PFAS, save yourself the time and cost by eliminating that material from your sampling program and find an alternative.

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The Future of PFAS
On a larger scale, the next step in PFAS research is to determine where PFAS contamination is primarily coming from. At certain locations, such as department of defense sites, airports, or refineries, the presence of PFAS is largely attributable to the use of Aqueous Film-Forming Foam (AFFF) to put out petroleum-based fires. AFFF is a chemical fire-fighting foam that contains high concentrations of PFAS chemicals. Unfortunately, this foam has been used historically for training purposes, not just in emergency situations, increasing the amount of PFAS in the environment. A large majority of PFAS testing nationwide has been done by the Department of Defense at various sites due to their routine use of AFFF and desire to prevent further environmental contamination.

PFAS can come from primary production of raw materials, typically water-proof materials, but also comes from landfill leachate at sites in which these primary PFAS-containing materials break down. More research over the coming years will help to determine the largest contributors of PFAS so that steps can be taken to mitigate human and environmental exposure to PFAS.

There is still much to be done in terms of PFAS regulation. In 2016, EPA set a lifetime health advisory limit for PFOA/PFOS at 70 parts per trillion (ppt); however, some scientists believe that to be ten times higher than the true healthy limit and many states have set their own PFAS limits between 10 and 20 ppt. On August 23, 2019, The CSWRCB lowered its drinking water notification levels for PFOA and PFOS based upon health recommendations received from the California Environmental Protection Agency (CSWRCB 2019). The notification level for PFOA lowered from 14 ppt to 5.1 ppt, and the notification level for PFOS lowered from 13 ppt to 6.5 ppt. As research about PFAS increases, states will be updating their notification levels to align with the most recent health and safety information available. EPA and other involved parties are continuing their research on the effects of PFAS and the phase-out of PFAS products. For now, it looks like more research will be done to determine the safest lifetime health advisory limit, and in the future, potential regulations may be put in place for instances where PFAS exposure is greater than specified limits.

If you are unsure whether your facility operations will be affected by future PFAS regulation, or if you are intimidated by the prospect of sampling for PFAS, reach out to an environmental consultant to discuss your position and available options. Although sampling for PFAS can be tricky, it is very achievable and can provide valuable data.

Blake et al. 2018. “Associations between longitudinal serum perfluoroalkyl substance (PFAS) levels and measures of thyroid hormone, kidney function, and body mass index in the Fernald Community Cohort.” Environmental Pollution 242: 894-904.

California State Water Resources Control Board. 2019. “Per- and Polyfluoroalkyl Substances (PFAS).”

California State Water Resources Control Board. 2019. “Per- and Polyfluoroalkyl Substances (PFAS) Sampling Guidelines.”

Environmental Protection Agency. 2019. “Basic Information on PFAS.” 

Ericson et al. 2012. “Per- andPolyfluorinated compounds (PFCs)in house dust and indoor air inCatalonia, Spain: Implications for human exposure.” Environmental International 39: 172-180.

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