The Do’s and Don’ts of PFAS Sampling
In April 2024, the US EPA announced enforceable limits for six per- and polyfluoroalkyl substance (PFAS) compounds in drinking water. While the impacts to existing compliance programs, such as local and federal discharge permits, are unknown, it is clear that the collection of representative samples for PFAS analysis is essential.
Don’t: Wait Until the Last Minute to Prepare
Cross-contamination can be an issue while collecting material for testing, but it becomes even more prominent during PFAS sampling. It is vital to avoid cross-contamination during collection, shipping, and beyond. Eliminating the introduction of PFAS during collection should begin at least 24 hours before sample collection.
Samplers should not use any hair products, soaps, body lotions, sunscreen, floss, etc. that are not certified as organic during the 24 hours prior to collection. Many household products include PFAS and could interfere with sample collection before sampling personnel even go into the field.
Do: Wear PFAS-free Clothing
Clothing should be a well-laundered synthetic or 100% cotton that has not been washed with fabric softeners. Waterproof clothing, boots containing Gore-Tex (or similar), and coated Tyvek® (or similar) suits should be avoided while sampling. Many brands have begun to produce clothing and shoes that are marketed as PFAS free, but check with the manufacturer before assuming that is the case or default to 100% cotton. A recent National Geographic article addressed this issue and featured a list of PFAS-free clothing brands. CNN also published a story on PFAS-free clothing with a list of manufacturers last spring noting that several manufacturers had actually started eliminating PFAS from their products during the past few years.
Don’t: Snack While Sampling
During the sample collection, eating and drinking near the collection point should be avoided. Many prepackaged food and drink packaging and containers can contain PFAS. Eating and drinking should be limited to the staging area.
Do: Choose the Right Tools for Recording Notes and Data
It is recommended that Sampling Teams have at least two people, this way one sampler can conduct sample collection while the other maintains records/data collection. Data/records can be collected on loose, non-waterproof, nonrecycled paper or Rite in the Rain® notebooks and aluminum, polypropylene, or Masonite clipboards. Avoid using waterproof treated paper (unless Rite in the Rain® branded) and plastic clipboards. Ballpoint pens, pencils, and Fine or Ultra-Fine Point Sharpie® markers can be used to take notes and label samples. Thin high-density polyethylene (HDPE) lining can be used to cover collection surfaces.
Do: Use the Right Sampling and Personal Protective Equipment
During collection, powderless nitrile gloves should be worn when handling sample containers before, during, and after sample collection. Sample containers should be made of HDPE or polypropylene with unlined polypropylene caps. Disposable and dedicated equipment should be made from HDPE, polypropylene, silicone, or stainless steel. During shipment, avoid using blue ice and stick with wet ice.
When decontaminating all equipment, it is recommended to use Alconox® and/or Liquinox® and laboratory-confirmed PFAS-free water.
Cross-contamination and improper sample collection, especially in regulated compliance programs such as National Pollutant Discharge Elimination System (NPDES) and wastewater sampling, can result in false positives, revocation of permits due to violations, or even the potential to be identified as a responsible party if downstream issues arise. Incorporating PFAS-specific sampling requirements and collection of appropriate field quality control samples will minimize cross-contamination opportunities and ensure representative samples are collected.
