26/2/20: PFAS Detailed Site Investigation
Toowoomba (Anzac Avenue) Fire Station, 201 Anzac Avenue, Harristown, Queensland Queensland Fire and Emergency Services
“The key findings of the PFAS DSI are presented below….
· PFAS compounds were detected in all 24 soil samples analysed with PFOS and PFHxS the main compounds present. The highest ∑(PFHxS+PFOS) concentration present was 0.54 mg/kg within shallow soil at 0.5 mbgl at TW_SS1, located in the landscaped area in the central portion of the site, adjacent and to the east of, the former foam training area…The source of the PFAS may be potentially due to the application of foam to the soil as a wetting agent or foam dispersed by wind during training exercises…
· ∑(PFHxS+PFOS) and PFOA concentrations in 24 soil samples analysed from five deep bores and seven shallow surface bores did not exceed NEMP (HEPA, 2018) health guideline values for a commercial land use. PFOS concentrations in the two soil samples from TW_SS1 (at 0.1 and 0.5 mbgl) exceeded the NEMP (HEPA, 2018) ecological indirect exposure guideline value for a commercial land use (0.14 mg/kg).
· The primary PFAS compounds detected in groundwater were PFHxS and PFOS with ∑(PFHxS+PFOS) in the range 0.02 to 8.56 ug/L in the five groundwater samples collected. ∑(PFHxS+PFOS) groundwater concentrations in four out of five groundwater samples exceeded the NEMP (HEPA, 2018) drinking water guideline value. The three groundwater samples with the
higher ∑(PFHxS+PFOS) concentrations in groundwater were from monitoring wells within the former foam training area (TW_MW02, TW_MW03 and TW_MW05) and concentrations in these wells also exceeded the NHMRC (2019) human health (recreational water) guideline value. Drinking water and recreational guideline values for PFOA were not exceeded in any of the
groundwater samples…
· There is the potential for PFAS in groundwater to extend off-site beyond the northern and western site boundaries at concentrations above human health and ecological guideline values…
· The PSI identified that waste foam was washed into the on-site drains following training exercises, indicating the potential for PFAS to migrate within the surface water drainage system and off-site. The analytical results for co-located surface water and sediment samples from two on-site surface
water drains indicated PFOS concentrations in both surface water samples (up to 0.37 µg/L at TW_SW2), which exceeded both the NEMP (HEPA, 2018) and proposed updated (Batley et al., 2018) ecological guideline value for 99% freshwater species protection. PFAS was also detected in the two co-located sediment samples with the highest ∑(PFHxS+PFOS) concentration detected
at TW_SED01 (0.07 mg/kg). The nearest surface water feature is an unnamed ephemeral channel located at distance (approximately 325 m northwest) from the site. The unnamed surface watercourse appears to flow to the southwest, discharging into Spring Creek approximately 3.6 km to the southwest of the site. The site appears to be within the Spring Creek catchment…
· Based on information provided as part of the PSI, the source of the PFAS detected in soil and groundwater samples is considered likely to be related to the historical firefighting training practices at the fire station, and spills from storage containers, product transfer and other maintenance activities.
Based on these key findings, the PFAS CSM developed for the PSI has been updated. A number of possibly complete exposure pathways for PFAS sourced from the fire station to impact off-site human and ecological receptors have been identified. The significance of these potentially complete sourcepathway-receptor linkages is uncertain and further investigation is required to understand the potential risks to off-site receptors.”
https://www.fire.qld.gov.au/sites/default/files/2024-04/3.6-Toowoomba-PFAS-DSI.pdf