Operations Mananger, Air Services-Northeast
Weston Solutions, Inc.
Wes Fritz has a B.S. in Physics from West Chester University. He has 28 years of professional experience managing, leading and performing stack sampling projects. He has performed emission testing for a wide variety of industrial clients including chemical manufacturing, petrochemical/refineries, power generation, manufacturing, and pharmaceuticals. He has led programs focused on developing stack testing methods to measure isocyanates and PFAS in source emissions.
Innovative Sampling and Analysis Techniques for Stack Sampling of PFAS Compounds in Air Emissions from Stationary Sources
Wesley Fritz and Paul Meeter, Weston Solutions, Inc., West Chester, PA, USA
Background/Objectives. Many per- and polyfluoroalkyl substances (PFAS) are known or suspected to be toxic to humans. Several routes of environmental exposure have been studied and primarily focused on drinking water and, to a lesser extent, groundwater and soil. Until recently, there has been little focus on PFAS exposure from air emissions at stationary sources and no stack sampling methodologies validated by the U.S. Environmental Protection Agency (EPA) have been developed. This has led to the development of unique and innovative sampling and analysis techniques during characterization of PFAS compounds in stack gas at multiple project sites.
Approach/Activities. Several PFAS compounds of interest have boiling points in EPA’s semi-volatile range; however, the traditional organic solvents employed to handle semi-volatile analytes derived from sampling trains are insufficiently polar to be used to complete sampling train breakdowns in the field, or extract sample fractions in the laboratory. Other PFAS compounds receiving attention as air source target analytes have boiling points that are in EPA’s volatiles range. Stack sampling for PFAS emissions has been performed at several chemical manufacturing facilities, one coating facility, and one sewage sludge incinerator facility using sampling methods developed in collaboration with a partnering analytical laboratory. Stack gas samples have been collected and analyzed using EPA Method 0010 and EPA Method 18 modified specifically for the unique characteristics of PFAS. Sources tested include the inlets and outlets of several air pollution control devices including carbon absorption units, wet scrubbers, and thermal oxidizers. The sample collection activities have been observed by representatives from state regulatory agencies and the test data have been thoroughly reviewed by EPA, state agencies, and community advocacy groups.
Results/Lessons Learned. To address the problem of sampling train solvent polarity, a modified version of the EPA Method 0010 sampling train configuration has been devised to effectively characterize hexafluoropropylene oxide dimer acid (HFPO-DA, also known under the trade name “GenX”) and perfluorooctanoic acid in stack gas. Conversely, PFAS compounds in the volatile range have been successfully characterized using a Modified Method 18 cryogenic midget impinger sampling train charged with methanol. The sampling train is chilled using a dry ice and methanol bath to assist the condensation and dissolution of the volatile PFAS analytes in the impinger solvent.
As air emissions come under heightened focus as a potential PFAS exposure pathway, the need for accurate and defensible PFAS emissions testing data is necessary. This presentation will discuss the derivation of the modified methods developed for the stack emissions sampling and analysis and the results and findings from this work.