ePrep supports PFAS testing in soil samples

PFAS soil testing

Investigating the forever chemical

 

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are synthetic chemicals known for their stability and durability, giving them the label the ‘forever chemicals’. Their properties make them ideal for use in countless commercial and industrial applications, ranging from food packaging and non-stick pans to electronics and fire-fighting foams. However, these unique characteristics have a darker side; their forever qualities have led to widespread accumulation, to the point where they are ubiquitous in nature, our food and even our bodies. This blog investigates the PFAS conundrum and the critical role of PFAS soil testing in monitoring and managing this environmental issue.

 

The impact of PFAS on the environment

The carbon-fluorine molecular bond in PFAS is one of the strongest in chemistry, which is the secret to the stability and robustness of these chemicals.1 This makes them perfect for uses that operate over wide temperature ranges or require stable and non-reactive substances, as well as effective surfactants or surface protectors.2 The chemicals were first harnessed for commercial use in the 1940s, and rapidly expanded into various applications, however, unfortunately, their stability has led to extensive environmental contamination, reaching even the most remote corners of the Earth.3 What’s even more concerning is the potential of these chemicals to build up in our bodies in a process called bioaccumulation.1 This can happen through a number of pathways, but PFAS contamination of soil is perhaps the most common, where these chemicals can easily be transferred to groundwater, crops and, eventually, humans.4 A number of health issues can stem from continued exposure, including altered metabolism and body weight regulation, increased risk of some cancers, and reduced efficacy of the immune system.1

 

PFAS testing

For decades, rising environmental levels of PFAS were seen as unproblematic, largely because legacy instrumentation found them to be non-toxic – an assessment that turned out to be wrong.4 Recent research and the availability of technology that can test for PFAS at very low concentrations have clearly shown that these chemicals negatively affect both the environment and our health.5 What the scientific world must now address is how to monitor and manage the buildup of PFAS in the environment, food, animals and humans, and soil is an obvious medium to regularly test so that any contamination can potentially be addressed before waterways and plant-feeding animals also become affected.

 

Challenges of PFAS testing in soil

 

Selectivity

There are literally thousands of PFAS chemicals, each with slightly different properties, making them difficult to study and detect in the presence of others.1 However, environmental degradation typically results in only a small number being of interest to environmental scientists.

Sensitivity

Most PFAS are present at extremely low concentrations – often down to the parts per trillion range – making them difficult to accurately quantify. It is therefore vital to have good laboratory practices in place, as well as highly sensitive instrumentation.

 

Contamination

The detection and quantitation of PFAS can also be hindered by the presence of other substances in a sample. As PFAS are ubiquitous, it is vital to ensure that they aren’t present in the measurement background, and that any labware or instrumentation isn’t contaminated.

 

Adhering to regulatory frameworks

Laboratories performing PFAS analysis are becoming more widespread in response to public health and environmental concerns, calling for standard methods that ensure reliability and robustness. For example, the U.S. Environmental Protection Agency (EPA) has published a key initiative – Method 1633 – to recommend a consistent methodology for testing a range of media with the required quality control.

 

It’s all in the method

While these challenges are real and evolving, two things remain steadfast: good laboratory methods can help to deliver accurate results, and high-quality instrumentation can provide the necessary sensitivity, precision and accuracy. The same is true for both targeted PFAS analysis – when looking for a list of specific compounds – and non-targeted analysis, when searching for unknown substances. Either way, solid-phase extraction (SPE) combined with liquid chromatography-mass spectrometry (LC-MS) is often the go-to approach for robust testing, as it provides the required sensitivity and specificity. However, while effective, manual SPE is a labour- and time-intensive method, and requires large sample volumes to achieve low limits of detection.

 

Accelerating sample preparation

We tackled the challenge of tedious manual workflows – like SPE – in PFAS soil testing head-on during the development of the ePrep® ONE, a fully automated sample preparation instrument for just about any chromatography application. This beast of a platform has already proven itself across multiple sectors, including environmental PFAS testing, as clearly shown in this application note. Here, we tested for PFAS in contaminated water samples, performing sample preparation using our µSPEed® Cartridges – which provide enormous separation power and high concentration factors in microlitre volumes – and automated the workflow on the ePrep ONE, which delivered some impressive results compared to manual SPE methods, including:

 

  • 5-minute extraction time versus more than 30 minutes;
  • 125 times less sample volume used (2 ml versus 250 ml);
  • significantly less elution solvent used.

 

Here to stay – for now

While some people may argue that the production of PFAS should be limited or even banned, these chemicals remain essential to many facets of society for applications in which alternatives do not yet exist.6 In the meantime, we must continue to explore ways to mitigate their propagation in the environment, ensuring they don’t end up in soil, crops, drinking water and, eventually, our bodies. PFAS remains a complex issue with many challenges that need to be addressed. However, scientists all over the world are investing more time and effort into the issue, and we are proud to support them in a small part by making workflows more productive with our innovative technologies.

 

References
  1. National Institute of Environmental Health Sciences. (2024). Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS). Accessed September 18, 2024. https://www.niehs.nih.gov/health/topics/agents/pfc
  2. Glüge J, Scheringer M, Cousins IT, et al. An overview of the uses of per- and polyfluoroalkyl substances (PFAS). Environ Sci Process Impacts. 2020;22(12):2345. doi:10.1039/D0EM00291G
  3. Wang Z, Dewitt JC, Higgins CP, Cousins IT. A Never-Ending Story of Per- and Polyfluoroalkyl Substances (PFASs)? Environ Sci Technol. 2017;51(5):2508-2518 doi:10.1021/ACS.EST.6B04806/ASSET/IMAGES/LARGE/ES-2016-048069_0002.JPEG
  4. Biegel-Engler A, Frauenstein J. PFAS in Soil and Groundwater: Comprehensive Challenges and Progress in Regulation and Management in Germany. Int Yearb Soil Law Policy. 2024;2022:285-304. doi:10.1007/978-3-031-40609-6_12/TABLES/2
  5. S. Food and Drug Administration. Per- and Polyfluoroalkyl Substances (PFAS). (2024) Accessed September 18, 2024. https://www.fda.gov/food/environmental-contaminants-food/and-polyfluoroalkyl-substances-pfas
  6. Glüge J, Scheringer M, Cousins IT, et al. An overview of the uses of per- and polyfluoroalkyl substances (PFAS). Environ Sci Process Impacts. 2020;22(12):2345-2373. doi:10.1039/D0EM00291G

 

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