A WA parliamentary question addresses potential PFOS contamination from Alcoa's Huntly bauxite mine, inquiring about further studies. The response indicates Alcoa initiated studies as the responsible party, with results to be publicly available upon completion and review.

AnsweredQoN 1133Legislative Council
Asked
11 December 2025
Portfolio
the Environment

QuestionView source ↗

Consultancy firm 360, in a report prepared for Alcoa Australia dated August 2021 as required under the Contaminated Sites Act 2003 , titled Huntly Bauxite Mine, Regional Surface Water and Source Water Dams - Stage 1, Detailed Site Investigation noted that PFOS and by-products from PFOS degradation were detected that suggestive of degradation from a fluorotelomer source. The report considered that PFAS impacts were likely associated with AFFF and may be originating from stormwater runoff from the failure of plant fire suppression systems, firefighting activities or dust suppression using impacted water on the conveyor line or haul roads. Given that Boronia Dam is unlined and is likely to be partly recharged by groundwater (and possibly ephemeral flows from the South Dandalup River), it is inferred that the PFOS may be attributed to impacted groundwater, potentially originating from the mining operation. It recommended that further work is required to confirm this. Considering the above, I ask: (a) has the Department of Water and Environmental Regulation initiated further studies; (b) if yes to (a), can the results of these studies please be provided in full; and (c) if not to (a), why not?

AnswerView source ↗

Answered
24 February 2026
Responded by
Minister for the Environment
Response time
5 days
(a)                    As the party responsible for the contamination, further studies were initiated by Alcoa in accordance with the requirements of the Contaminated Sites Act 2003 . Alcoa has advised the Department of Water and Environmental Regulation (the Department) that a detailed site investigation (DSI) has been completed, and is currently being reviewed by their accredited contaminated sites auditor.
(b) – (c)            When the DSI has been completed, the auditors report, and any other relevant reports are submitted to the Department, they will be available to the public through a Detailed Summer of Records (DSR) request.

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