Groundwater Investigations and Assessments at Sites Impacted by PFAS
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Per- and polyfluoroalkyl substances (PFAS) consist of more than 5,000 manmade fluorinated organic chemical compounds that have been extensively manufactured since the mid-20th century.

PFAS have been widely used due to their unique physical and chemical properties (e.g., surfactant, oil- and water-repelling, etc.) and are considered emerging environmental contaminants of concern due to evidence of their potential human health effects or environmental risks.  They also often have no regulatory cleanup standard or a standard is evolving. One widely recognized use of PFAS is as a component in aqueous film forming foam (AFFF), which has been stored and used by the military, airports, and other firefighting and fire-training facilities (FTFs) to extinguish hydrocarbon fires. Geosyntec was retained to conduct preliminary assessments at fire training facilities throughout Florida and at a large, federal facility. The objective of these investigations was to assess the presence or absence of PFAS in groundwater, sediment, soil, and surface water.

Scope of Services

Our review of the previous site usage and interviews with staff from the FTFs identified potential PFAS release locations, mainly associated with the use of AFFF. The review of previous site usage and investigations and interview with staff from the federal facility also identified releases of PFAS that were associated with the use of AFFF, sewage treatment plants, sludge disposal areas, and landfills. The scopes of work for these investigations included preparing work plans and collecting hundreds to thousands of environmental samples. The scientific methods for PFAS investigations are in the early stages of development, so we prepared Standard Operating Procedures that represented an abundance of precaution to avoid potential cross contamination and false-positive results. The development and adherence to the SOPs were warranted because PFAS are present in a variety of commonly-used materials and the laboratory method detection limits are extremely low.

Geosyntec developed a human-health screening process for PFAS in soil and groundwater and a surface water screening process to identify human-health exposure pathways and/or sources of PFAS to groundwater.  We presented the field activities and results in reports that were submitted to the regulatory agency, which included recommendations for a path forward to complete delineation of affected media.

Our preliminary assessment of the FTFs identified PFAS-impacted media at 11 of the 13 investigated and we have been tasked to continue investigations at four of them. Ongoing work at one FTF includes a detailed investigation of a soil source area and we have been discussing a preliminary soil source removal to depths of about 40 feet. Investigations at the other FTFs involve a multi-media site assessment that includes a desk-top assessment to identify potential nearby receptors and potential off-site PFAS sources, and the investigation and delineation of PFAS-impacted soil and groundwater. They also include a forensics component to ascertain if groundwater data suggest that other off-site PFAS sources are potentially present.

Notable Accomplishments

Geosyntec's initial investigation at the federal facility, completed under an expedited timeframe, was one of the largest PFAS groundwater investigations in the state. The regulatory agency approved our report and a work plan to complete the delineation of PFAS-impacted media, and our work this far at these AFFF-impacted sites is advancing the state of PFAS investigations in the state of Florida.

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Project Summary

  • Location: Florida
  • Client: Confidential
  • Project Practice Areas: Contaminated Sites
  • Type of Facility: Industrial facilities
  • Services Provided: Document reviews, Groundwater and other multi-media environmental sampling, Human health screening, Conceptual site modeling
  • Type of Work: PFAS groundwater investigation
  • Governing Regulation: Federal and state regulations