A How-To for Sampling Water & Wastewater to Detect PFAS
PFAS can be detected in trace amounts in water and wastewater, but obtaining an accurate assessment is a challenge due to the widespread nature of the chemicals. Exacting steps must be taken before, during and after samples are obtained to ensure they are not compromised.
As experts in water and wastewater sampling and flowrate measurement for more than 60 years, Teledyne ISCO is uniquely qualified to assist in determining and implementing best practices that take much of the guesswork, wasted time, unnecessary expenses, and inaccurate analysis due to compromised samples out of the equation.
For more detailed information specific to your application, contact our Water Product Support team at [email protected] or in the United States, toll-free at 866-209-6174.
Equipment Choices/Material Selection
PFAS sampling is conducted similarly to other sampling projects. Due to the prevalence of PFAS in our environments and the extremely small quantitative measurements (0.02 ppt) in the EPA guidelines, the potential for cross-contamination is significant. Therefore, greater care is required to avoid compromising the quality of the collected water sample.
Sources of contamination
Avoid the following before and during sampling or while at the sampling site. While not an exhaustive list, these points demonstrate the prevalence of PFAS and the care that must be taken.
Personal sources of contamination: soaps, shampoos, insect repellants, sunscreen, moisturizing lotion, cosmetics, some toothpastes
Clothing washed with fabric softeners or marked as stain-resistant/waterproof
Fast food containers/packaging, food or drink in sealed packages (e.g., juice boxes)
Materials that are NOT in direct contact with the sample but should be avoided include: GPS receivers, notebooks, clipboards, etc.
Please note that PPE could contain PFAS. However, never compromise safety for the sake of eliminating PFAS material. If there is no equivalent PFAS-free option available, document the use of such and use a blank sample to establish a baseline presence of PFAS with the equipment and the exposure potential.
Materials to use or avoid in sampler parts
At the top of the list of materials that must be avoided, DO NOT USE PTFE or FEP tubing or any tubing that contains fluoride for suction line or any part of the sampler equipment. Use high-density polyethylene (HDPE) sample collection bottles. Avoid low-density polyethylene (LDPE) unless verified to be PFAS-free.
Approved Materials
Materials to avoid or use with caution
- LDPE (unless PFAS-free verified)
- Glass (unless PFAS-free verified)
- Teflon or related materials
- Any fluoropolymer materials
- Gel-Paks
Equipment considerations
- Sampling equipment should be dedicated to sampling PFAS.
- Decontamination is a MUST due to the sensitive nature and cross-contamination threat. This is often accomplished by a thorough rinse of the sample lines using known PFAS-free water.
- Communicate with your analytical laboratory and appropriate regulatory agency for their specific decontamination recommendations.
