Weston Solutions, Inc.
Robert Appelt has a B.S. in Geology and a M.S. in Geochemistry from the New Mexico Institute of Mining and Technology. Mr. Appelt's has over 20 years' of professional experience serving a variety of clients in primarily the commercial and industrial sectors at their most challenging multi-contaminant sites.
Innovative Approaches for Investigation and Remedial Activities at PFAS Sites in Variable Regulatory Environments
As emerging contaminants, the per- and polyfluoroalkyl substance (PFAS) class of compounds is the focus of ongoing regulatory developments. While current regulation is focused primarily on drinking water, environmental focus is turning in earnest to surface waters, soils, biosolids, and air. This uncertain regulatory environment presents challenges to the planning and execution of assessment and remedial activities. This process is made even more complicated by the fact that PFAS sites can have a range of contaminant mixtures in various media while the applicable regulatory sampling and analytical requirements and action levels can vary and often do not yet exist. Site investigations were started at several facilities in Texas, New Hampshire, North Carolina, and New Jersey that historically handled or disposed of PFAS-containing compounds. At these facilities, PFAS have been confirmed in soil, groundwater, surface water, or stack emissions. The applicable State regulations were and remain in various stages of development, adoption, and/or promulgation for any kind of regulatory criteria related to PFAS compounds. For example, in Texas, no such criteria existed, but regulations allow investigators to develop preliminary screening criteria. With concurrence from the State, those values could be used as action levels. Conversely, New Hampshire and New Jersey have some of the strictest standards in the United States. As subsequent investigations to delineate impacted media are completed at the sites, states continue to adopt and revise criteria. In at least one instance, PFAS criteria were revised for regulated compounds and criteria for 14 additional PFAS compounds were promulgated. The continued regulatory changes result in iterative attempts to complete site investigation activities; with each new update requiring additional investigation. The outcome is extended project life cycles with multiple challenges to the client as they try to meet regulatory action and reporting schedules. The continually and rapidly evolving regulatory framework has resulted in project delays from investigation phases to selection of remedies and achieving closure. Concurrent to setting applicable regulatory criteria, additional work is being done to develop sampling and analytical methodologies. The fate of transport of PFAS in air is a significant and growing concern. Currently, limited regulatory guidelines and no EPA-approved analytical methods exist for stack emissions sampling. Here, we present our work in the development of a defensible methodology for sampling PFAS in stack emissions with comparison to other methods available. Our method provides reliable results in the sampling process and facilitates mass balance analyses. Due to the recalcitrant nature of PFAS, we have revisited and developed remedial strategies to be applied that meet current regulatory requirements as well as anticipated future developments in treatment and disposal of impacted environmental and remediation derived media. This presentation will detail the evolving site characterization and investigative approaches; developing investigative strategies to accommodate the expected changes in action levels; and the results of methods developed for stack emission sampling.