Investigation of PFAS in Air, Dust and Soil: Exposure at a Fire Station
Sellén & Filipovic AB, in collaboration with Eurofins Pegasuslab and the Eurofins European PFAS Competence Center, conducted an investigation commissioned by a fire station and its associated training field in central Sweden. The aim was to map the presence of PFAS in indoor air, dust, and surface soil, and to assess potential exposure risks for personnel. PFAS are present in firefighting foam (AFFF) and can spread via air, dust, and soil, particularly in environments where foam is handled, or equipment is stored. Sampling was carried out in three indoor locations: a basement storage room with older equipment, a foam storage room where firefighting foam is handled, and an office. Soil samples were taken from three outdoor areas. Air samples were collected over 24 hours, dust was sampled from floors and shelves, and soil from the top 10 cm. In the office, Eurofins’ “triple wipes” method was used for dust sampling. A total of 68 PFAS compounds were analyzed, including precursors that can transform into perfluorinated PFAS over time.
Results – PFAS in Air, Dust, and Soil
The highest concentrations in air were measured in the basement storage, followed by the foam storage. The office had the lowest levels. Fluorotelomer alcohols (FTOHs) dominated, particularly 8:2 FTOH (250 ng/m³ in the basement) and 6:2 FTOH (30 ng/m³ in the foam storage). Regarding dust, the foam storage exhibited extremely high levels of DPOSA (Capstone A; 2,500 mg/kg), indicating spillage. The basement storage had high levels of legacy PFAS compounds such as PFOS (510 µg/kg) and PFOA (220 µg/kg). The office had significantly lower levels, e.g., PFOS at 1.8 µg/kg. FTOHs were highest in the foam storage (e.g., 12:2 FTOH at 360 µg/kg), while the office and basement had more moderate levels (e.g., 10:2 FTOH at 35–48 µg/kg). All soil samples showed a complex PFAS composition with total concentrations ranging from 100–500 µg/kg dry weight, all exceeding guideline values for less sensitive land use (MKM). The sample taken near the fire pond had particularly high levels of FTOHs, suggesting a recent contamination source. PFOS ranged from 21–300 µg/kg dry weight, and both DPOSA and 6:2 FTAB were found in low concentrations.
Risk Assessment and Recommendations
Based on the results, an assessment of PFAS exposure was conducted. Airborne exposure was below EFSA’s tolerable weekly intake (TWI) for PFAS4, but the risk increases due to precursor transformation. To reach the TWI via dust ingestion, one would need to ingest 0.38 g of dust from the basement, 1.35 g from the foam storage, or 330 g from the office—highlighting significant variation in risk levels. Recommended measures varied between locations but primarily included increased cleaning, removal of equipment, sealing of materials, etc. The investigation indicates that targeted actions can potentially reduce PFAS exposure and improve the working environment. Follow-up sampling will be conducted after the measures are implemented.
Conclusion
The combination of a broad exposure survey and advanced analytical PFAS methods proved essential for making a relevant assessment of the work environment. Analysis of PFAS in indoor air is a relatively new field that deserves attention in future investigations. Contact Eurofins for questions regarding methodology and analytical capabilities.
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Eurofins Pegasuslab (Air)
Eurofins Environment (Soil, Dust)
Product Sheet PFAS in Air