Breaking down the complexities of PFAS

Definition and Background of PFAS

The per- and polyfluoroalkyl substances (PFAS) are a group of chemicals used to make fluoropolymer coatings and products that resist heat, oil, stains, grease, and water. Within the PFAS group of Forever Chemicals there also sit a large number of Perfluorooctane sulfonate (PFOS). The term ‘PFOS-related substances’ is commonly used to refer to any or all of the substances that contain the PFOS part that may break down in the environment to give PFOS.

PFAS chemistry was discovered in the late 1930s and, since the 1950s, many products commonly used by consumers and industry have been manufactured with or from PFAS. Two major processes, electrochemical fluorination (ECF) and fluorotelomerization, are used to manufacture PFAS substances that contain perfluoroalkyl chains. More than 600 intermediate processes have also been used to further produce certain PFAS and the associated final products.

PFAS have been and still are widely used, but not all types and uses of PFAS result in the same level of environmental impact and exposure. When considering potential environmental and human impacts from PFAS, it is critical to be as specific as possible not only about the particular PFAS involved but also where and how they are released to the environment.

For many years, PFAS were thought to be inert and non-toxic and were extensively used with little thought for environmental disposal or ecological impact. It was not until early this century that the extent of PFAS global contamination was first realized.

The research on PFAS compounds has identified them as being persistent and bio-accumulative, and their widespread use has led to them being almost ubiquitous in the environment. Because PFAS do not break down, they enter the environment through production or waste streams. There are over 4,000 PFAS compounds thought to have been manufactured and are now potentially in the environment globally.

"PFAS are a new style of pollutants that don't follow the 'rules' of traditional organic pollutants," says Bradley Clarke, senior lecturer in Analytical Chemistry and Environmental Science, at the University of Melbourne in Australia. "This is why regulators and scientists, unfortunately, failed to predict how these chemicals would move through the environment, and why we now have a serious problem of such widespread PFAS contamination of drinking water, agricultural land, and the domestic environment."

Impact of PFAS on human health

Like other chemicals, PFAS is potentially capable of producing a wide range of adverse health effects depending on the circumstances of exposure and factors associated with the individuals exposed.

Aspects to consider when establishing the health effects of greatest concern are effects for which potential impact is greatest (factors contributing to impact can include severity of effect, functional impairment, persistence, and specific age groups that are susceptible, as examples), and effects for which evidence is the strongest (strength of evidence can come from consistency of effect across studies, strength of effect associations in epidemiological studies, and species concordance, as examples).

Understanding PFAS Testing

Importance of Accurate Detection

According to the US EPA, there are over 9,000 PFAS compounds that have been used in industry and commerce. However, global regulatory lists, show the number of PFAS that are currently under regulatory overview is less than 50. So, for regulation, there are less than 1 to 2% of the number of currently known PFAS being observed. This shows we are only at the start of PFAS testing and can expect regulatory lists to continue to grow with an expansion of standardized PFAS extraction and PFAS analysis methods.

People can be exposed to low levels of PFAS compounds through consumer products that contain PFAS, such as carpets, leather and apparel, textiles, paper and packaging materials, and non-stick cookware. Drinking water can also be a source of exposure in communities where these chemicals have contaminated water supplies, such as an industrial facility where PFAS were produced, or used to manufacture other products, or an oil refinery, airfield, or other location at which PFAS may have been used for firefighting.

Overview of PFAS Testing Techniques

PFAS analysis is performed using traditional analytical instrumentation, in particular coupled chromatography with mass spectrometry LC-MS/MS. This approach is selective and quantitative with detection limits in the low ppt range. Currently approved EPA methods involve the use of solid-phase extraction (SPE) to concentrate the sample followed by LC-MS/MS analysis.

One of the critical aspects of collecting balanced PFAS data is to have standard methods that provide reliability and robustness, no matter where they are performed. The US EPA has two methods for the analysis of PFAS in drinking water, and another method for PFAS analysis in wastewater and surface water. The EPA is also currently creating a method for PFAS testing in wastewater and soil. Several other consensus organizations are working on routine and regulatory methods as well.

The ISO has many standards concerning PFAS in leather, water quality, and LC-MS detection techniques.

Given the sensitivity required in detecting PFAS across the entire spectrum, labs need to be confident they have a high-purity hydrogen solution to supply their equipment. The Precision Trace series of hydrogen generators is ideal to provide hydrogen at up to 99.99999% purity. 

Challenges in PFAS Analysis

Matrix Interference

Since PFAS have been widely used for decades and do not easily break down, these compounds have been detected in almost every ecosystem that interacts with humans. PFAS have been detected in drinking water, wastewater, soils, food, and air—showing large-scale environmental exposure. PFAS are used in several consumer products such as nonstick cookware, stains and water repellents, paints, cleaning products, food packaging, and even cosmetics.

Additionally, several studies have also shown PFAS to be globally present in the blood of wildlife and humans. As a result, there is a need for many PFAS detection methods for various matrices including, for example, how to measure PFAS in water, PFAS testing in soil, PFAS testing in food, PFAS testing in air, biosolids PFAS testing, and more.

Conclusion

Future research on the health effects of replacement PFAS and routine studies on legacy PFAS must apply “lessons learned”. There are only a small number of PFAS with enough health effects data for use in decision-making, as evidenced by state-led standard setting. There are numerous health effects reported for those PFAS tested, which sets this family of chemicals apart from many others and elevates the need for precautionary action.

With hundreds of PFAS lacking health effects data, translational research teams using innovative methodologies and carefully designed studies will be critical to the state of knowledge on PFAS-related health effects and our enhanced strategies for informing risk assessment of this large family of chemicals.