What is PFAS?
Per- and polyfluoroalkyl substances (PFAS) are a general term applied to thousands of chemicals manufactured since the 1940’s and can be found in food packaging (microwave popcorn bags, pizza boxes, etc.), stain and water-resistant fabrics, non-stick products, fire-fighting foams, and many other consumer and manufacturing products. They have been widely used for many decades because of their unique surfactant and oil/water repelling qualities. When sampling for PFAS there are several things to consider to help avoid cross-contamination.
Why Should We Care About PFAS?
PFAS are considered an emerging chemical of concern and have been classified as “Forever Chemicals” because they do not easily break down in the environment. PFAS also bioaccumulate in the food chain and can end up in humans primarily due to ingestion of food or water contaminated with the chemicals.
Why is Sampling for PFAS More Complicated?
Due to the low screening level concentrations (ng/L) and prevalence of PFAS in consumer products, false positives are a major concern due to cross-contamination between sampling locations and contamination of samples.
As a result, we have listed ten items that are restricted when it comes to sampling for PFAS.
- Sampling equipment with Teflon® components. Initial studies are showing that Teflon® tape leaches PFAS compounds, but Teflon® fittings in pumps may not.
- LDPE plastic (Ziploc® bags, lab containers, tubing, clipboards)
- Plastic fittings made of PVDF (Kynar®), PCTFE (Neoflon®), ETFE (Tefzel®), FEP (Hostaflon®)
- Glass containers/bottles
- Aluminum foil
- Sharpie® or other thick markers
- Post-it® or other branded sticky notes
- Rite in the Rain® or other branded waterproof paper
- Blue ice packs or any other chemical ice
Additionally, below are six field clothing items that are also restricted for PFAS sampling.
- New, unlaundered clothing
- Clothing laundered with fabric softeners
- Clothing and boots with stain/water/dirt/oil-resistant chemicals applied, such as Gore-Tex®, Scotchgard™, and MANY others.
- Clothing treated for insect resistance (permethrin) or ultra-violet (UV) protection
- Latex gloves
There is a lot to consider when preparing for PFAS sampling, so make sure you’re using the correct materials to avoid contamination of your samples.
See 10 Acceptable Items to Use When Sampling for PFAS for the correct materials.
Questions? Ask our expert, Jason Hoffman!