A Holding Time Evaluation of the Stability of "Forever Chemicals" in Wastewater

Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Prepared by C. Neslund, R. Singh
Eurofins Lancaster Laboratories Environment Testing, 2425 New Holland Pike, Lancaster, PA, 17601, United States

Contact Information: [email protected]; 717-556-7231


For the analysis of PFAS in drinking water there are two EPA sanctioned methods, 537.1 and 533. Each of different vintage and compound list (18 and 25 respectively) but they do share 12 compounds in common. Each is prescriptive in the use of container and preservative. EPA 537.1 uses Trizma as a chlorine scavenger and buffer. EPA 533 uses ammonium acetate for the same purposes, yet they have different holding times. EPA 537.1 uses a 14 day from collection, extraction holding time and EPA 533 uses a 28 day from collection, extraction holding time. Each requires storage at refrigerator temperatures. But these holding times were developed for application to drinking waters. These holding times, via reference to a “water” matrix, are then used by extension to wastewaters of many sorts, in user defined methods.

The new multi-matrix method being developed by collaboration between EPA and DoD looks to be citing holding times and storage conditions cited in a single, published laboratory study. With a healthy dose of skepticism, we decided to undertake our own holding time study using actual wastewaters and several different temperature storage conditions with the intention of verifying the previously published work or providing an alternative set of data to facilitate the continued discussion.

This presentation will present the results of our study and will provide the following:
• Comparison of the different temperature storage conditions
• Comparison of the wastewater results versus laboratory grade water
• Comparison of the performance of the different chemistries of PFAS against the different storage conditions