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.
The Tomago Sandbeds are a safe and reliable back up water supply for the Lower Hunter. They can be operated during times of shortfall and provide 20 per cent of the region's drinking water. Hunter Water has embargoed, or isolated, two of its bore stations that are located in the Williamtown Management Area 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.
In the event the Tomago Borefield is operated, a monitoring program is initiated which tests sections of the Borefield prior to connection to the system, and assurance testing is regularly carried out during times of operation. Any decision to use the Tomago Sandbeds as a drinking water supply will be made in consultation and with the approval of NSW Health. The monitoring and assurance regime has been endorsed by the NSW PFAS Expert Panel.
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.