PFAS and Field Blanks: A Lab Perspective

Presented by Sarah Choyke, Eurofins Environment Testing – Denver CO
Contact Information: [email protected]

ABSTRACT

PFAS are contaminants of emerging concern found in almost every environmental matrix including drinking water, biosolid and wastewater. EPA Drinking water methods and several States require the collection of field blanks for all sampling events, however, after thousands of field blanks have been analyzed, there have been minimal target PFAS detections. Laboratories that perform PFAS testing are struggling to keep pace with the increase in sampling campaigns and are turning to innovative solutions to keep up with demand. The laboratory takes two approaches to deliver high quality data to the clients, (1) maintaining laboratory practices and (2) working with clients to prioritize data delivery.

Given the current reporting limits for drinking water and non-potable water, detections are rarely seen in field-based blanks, including field blanks, trip blanks, and equipment blanks. However, if the reporting limits for PFAS drop significantly, the likelihood of field based blank detections would increase as well as finding a reliable source of PFAS-Free water. Currently, the laboratory has found that not all purified or DI water treatment systems are “PFAS-Free” and PFAS-free water must be tested by the lab staff to ensure high quality data is maintained. Lab staff must also be very careful about not introducing any PFAS contamination into a sample. The lab staff uses “best practices” when handling PFAS samples, including frequent glove changes, cleaning and changing tubing, and limiting outside materials such as personal care products, recreational or waterproof gear, and floor or ski wax in the working areas.

Some clients decide that to maintain QC consistency across a project, all samples should be batched and analyzed together. While other clients choose to collect field blanks and decide to analyze them after the initial results are reported. If they suspect gross contamination across all samples, the field blanks may be activated usually outside of hold time to confirm the detections. It is critical that both the laboratory and the client understand and communicate the requirements at the site to ensure success and completion of the project.