Perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS) are part of a family of manufactured compounds called per- and poly-fluoroalkyl substances (PFAS), which are used in a wide variety of applications. They are emerging contaminants that bioaccumulate in the environment, and are commonly found in and around populated areas throughout Australia and internationally.
PFAS and Drinking Water
The drinking water Hunter Water supplies is regularly tested throughout the water supply system, and complies with the National Health and Medical Research Council's Australian Drinking Water Guidelines (ADWG).
In consultation with NSW Health, Hunter Water has adopted the ADWG for PFAS of:
- less than 0.07 micrograms per litre for PFOS and PFHxS (combined); and
- less than 0.56 micrograms per litre for PFOA.
Hunter Water routinely samples for PFAS in all of its drinking water supply zones, and reports detections over 0.002 micrograms per litre, which is our independent laboratory's limit of reporting.
All results available to date show drinking water supplied by Hunter Water is safe to drink.
Hunter Water includes PFAS results in our monthly water quality report.
PFAS and Grahamstown Dam / Tomago Sandbeds
Although Grahamstown Dam is only a few kilometres away from the RAAF Base Williamtown, the source of a local PFAS contamination plume, it impossible for water to enter Grahamstown Dam from the RAAF Base due to the direction of surface and groundwater flows in the area. Water would need to flow uphill to enter the dam, even in wet conditions. This assessment is based on decades of ongoing hydrological testing and modelling.
Part of the Tomago Sandbeds have been affected by contamination from the RAAF Base Williamtown. Hunter Water has embargoed, or isolated, three of its bore stations in the Sandbeds as a precaution while further investigations are undertaken. It is possible that some or all of these bore stations may be able to supply safe drinking water again in the future if appropriate management strategies can be implemented. The Tomago Sandbeds is used as a backup water source, and the water is tested for contaminants including PFAS before it enters the drinking water supply.
For more PFAS related information on ground and surface water flows in the Grahamstown Dam / Tomago Sandbeds area, download the Williamtown to Campvale Hydrology Report.