Taryn McKnight, Product Manager for Eurofins TestAmerica based in Sacramento, California, has more than 15 years of experience in the environmental testing industry. Ms. McKnight is the company’s subject matter expert on PFAS and Vapor Intrusion. She has extensive experience with a wide variety of complex regulatory programs such as Department of Defense, Vapor Intrusion, and emerging contaminants. In her current role she is responsible for providing technical guidance and support to clients, agencies and industry personnel across the country.
State of the Science: PFAS Sampling Guidelines and Frequency of Cross-Contamination
What makes a PFAS investigation different is the potential for sample contamination from commonly used consumer products and sampling materials. Per- and Polyfluoroalkyl substances (PFAS) are a large group of manufactured compounds used in a variety of industries. With their widespread distribution and target detection limits in parts per trillion (ppt) there is heightened concern regarding the potential for cross contamination. Growing concern over PFAS in the environment has led to significant increases in the number of investigations to identify sources and determine the extent of environmental impacts. A complicating factor is the lack of published EPA methods or guidance for addressing PFAS in various media. The Agency is working to develop validated analytical methods for groundwater, surface water, wastewater, and solids, including soils, sediments, and biosolids, but these are all in various stages of development and review. Over the past several years various State, Federal, and private agencies have developed their own protocols and recommendations specific to the collection of samples for PFAS analysis. This presentation will review what is available and being utilized today from published guidance on PFAS sampling protocols. This review includes several State, Federal and trade association documents. We will take a look at the available checklists containing acceptable and prohibited items, and, more importantly what data there are to substantiate these lists or that conflicts with certain claims. Lastly, we will present data from tens of thousands of samples from around the country to see what frequency of detections there are in field quality control samples and what these data might tell us about our current approach.