PFAS contamination is a pressing environmental challenge facing industrial sites today. At a former fire-damaged storage facility, we investigated whether the property warranted further remediation.
Case Study: Industrial Storage Site With Historic Magnesium Fire
We were recently awarded a project investigating an industrial storage site with a historic magnesium fire. The property owners reported Aqueous Film Forming Foam (AFFF) was possibly used to put out the fire 20 years ago. Knowing PFAS would be a site consideration due to AFFF use, we recommended PFAS sampling.
How do we know when a PFAS site requires remediation?
We had to look at the region screening levels…
What are Regional Screening Levels (RSLs)?
Regional Screening Levels (RSLs), are values of chemical concentrations created by the EPA for cleanup professionals to initially characterize cleanup sites. Toxicologists use known exposure information about the chemicals and standardized
equations to calculate the concentration of a chemical in soil, air, or groundwater that is no longer safe to humans, including sensitive groups.
Sites that are found below the RSL for a chemical would likely require no further action. Sites that are above the RSL could require further evaluation and remediation depending on the source, saturation, and possible spread of the contamination. Additionally, the RSLs are limited to human health effects and do not consider ecological effects from contamination.
The current screening levels for PFAS chemicals are in the nanogram per gram of soil range, meaning even a tiny amount of PFAS at a site would indicate potential remediation; however, due to the recent emergence of the compounds, there is no set remediation enforcement for PFAS on a federal level and sites of potential concern are evaluated on a site-by-site basis. The current PFAS sites of concern are manufacturing sites, military bases, airports, and landfills.
What is the Laboratory Capable of?
We had to ask about the method detection limits…
What are Method Detection Limits (MDLs)?
Method Detection Limits (MDLs) are the detection limitation of the method used to test a sample, including pretreatment, preparation, and the equipment used. The limit of the method is considered the smallest concentration detectable with 99%
reporting confidence. Smaller concentration detection requires equipment with higher sensitivity.
We were not surprised to find out our samples for the nanogram per gram range of concentration would be a significantly higher cost and longer turn-around-time.
Based on our clients risk tolerance, the current PFAS enforcement, and the fact we did not encounter groundwater during sampling, we chose to analyze the samples at the microgram per kilogram concentration of PFAS. If the potential contamination were detected at that level of concentration, it would indicate a release of PFAS chemicals potentially migrating to neighboring properties or groundwater and further investigation would be required.
Results
We were pleased to find no detections of PFAS in any soil sample. PFAS may still be present on the site, as we know it very common, however, indications of a PFAS release with the potential to impact users of the site or neighboring properties was not identified based on our sampling. No further action was required for the site. Our client was able to move forward with confidence knowing no further PFAS action was required based on current regulations.
For more background information on PFAS, view our previous blog posts, Washington State CLARC PFAS Updates (2024) and “Dark Waters” – The Story of PFAS Regulation.
Updates and new regulations are a constant in our world. McAlister GeoScience dedicates time and resources to researching the latest enforcement information and guidance to ensure our clients are getting quality and accurate reports on their properties. Click here for more information regarding our services.
Resources
https://www.epa.gov/risk/regional-screening-levels-rsls-frequent-questions
https://www.epa.gov/cwa-methods/method-detection-limit-frequent-questions
https://www.epa.gov/sites/default/files/2016-12/documents/mdl-procedure_rev2_12-13-2016.pdf
https://www.usfa.fema.gov/blog/firefighting-foams-pfas-vs-fluorine-free-foams/#:~:text=Per%2D%20and%20polyfluoroalkyl%20substances%20(PFAS,to%20fighting%20liquid%20fuel%20fires.
https://www.epa.gov/pfas/our-current-understanding-human-health-and-environmental-risks-pfas
https://www.epa.gov/system/files/documents/2024-04/pfas-enforcement-discretion-settlement-policy-cercla.pdf