In NSW, water pollution is defined as introduction of anything into waters that changes their chemical, biological or physical nature. This obliges the NSW Environment Protection Authority to regulate all non-trivial impacts of water pollution on the environment, including potential impacts from emerging contaminants which lack robust environmental guideline values.
This paper outlines the scientific data informing the NSW Government’s policy around per- and polyfluoroalkyl substance (PFAS) contamination originating from RAAF Williamtown. The discussion is framed in the context of the State Government’s advice to minimise local community exposure to PFAS, implemented as a precautionary measure while the Commonwealth Government conducts its site characterisation, risk assessment, and remedial works at the base. The precautionary advice is underpinned by a diverse array of hydrological, toxicological, and geospatial data including Defence-commissioned studies, State-conducted investigations, and advice from the Williamtown Expert Panel and technical Working Groups.
Here, development of key scientific inputs are discussed, including: the regional-scale conceptual model of PFAS transport from the base; the maximum likely impact area from hydrological and contaminant transport principals; and, the Investigation Area boundary – a geospatial product synthesizing hydrological and cadastral data to support Government’s community engagement efforts. Additionally, the challenges public-service scientists face when providing policy-ready scientific advice in the face of evolving guideline values are examined.