2010-20: Nelsons Borefield, Ayr. PFAS detected

Nelsons Borefield Raw Water Quality 2010-2020

In recent times however, PFAS chemicals were detected in this borefield above the ADWG health guideline value that was first incorporated into the Australian Drinking Water Guidelines (ADWG) in August 2018. This has resulted in Council decommissioning Bores 2 and 5 and taking Bore 3 offline. Bores 1, 4 and 6 are currently below ADWG values but have been blended in some instances to achieve this result. The results from these bores are regularly monitored and reported to DNRME and Queensland Health. Subsequent investigations have identified the Ayr Fire Station as a highly contaminated site. While the exact pathway for contamination of the drinking water bores has not been elucidated (it may be from a PFAS plume emanating from the QFES site, stormwater that washes off the Fire Station Site, or from direct application of firefighting foam to the surface within Nelsons Lagoon), Council now has to manage the impact. Currently bores are operated in pairs, pumped to the Ayr Water Tower directly. This has effectively managed to maintain PFAS levels below the health guideline now that we have developed an understanding of the behaviour of each bore in the borefield. The risk is further mitigated with the blending of bore water from the Chambers Bores 15 and 16 and the construction of a 450mm trunk cross connector directly linking South Ayr to the Ayr Water Tower. It is Councils understanding that QFES is now undertaking the offsite component of a Contaminated Land investigation to identify the extent and direction of expansion of the contamination plume. It is understood that QFES and the Department of Environment and Science will continue to provide information to Council to allow us to understand the extent of the problem. It is expected that Queensland Health and the Department of Natural Resources Mines and Energy will also advocate for an appropriate infrastructure solution given the contamination is out of the control of Burdekin Shire Council

PFOA 0.01ug/L (max), 0.004ug/L (av.)

PFHxS 0.13ug/L (max), 0.0284ug/L (av.)

PFOS 0.26ug/L (max), 0.046ug/L (av.)

PFHxS/PFOS 0.43ug/L (max), 0.0813 (av.)

Pesticides also detected