THE Hunter’s main drinking water source is being tested for contamination from the Williamtown RAAF Base.
The Newcastle Herald can reveal Hunter Water has begun testing Grahamstown Dam for traces of perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA).
They are the same emerging contaminants found in ground water on properties at Salt Ash and Williamtown, as well as in the Hunter River, since the Department of Defence admitted the chemicals had leaked off the base.
The dam supplies about 40 per cent of the lower Hunter’s drinking water, and is the region’s largest water supply.
Hunter Water has been testing pump stations inside the Tomago Sandbeds since 2012 when Defence first admitted they had contamination inside the airbase, and in November the Herald reported three bores had been shutdown indefinitely, potentially costing tens of millions of dollars and about 1.5 billion litres of water annually.
Now, due to what it says is “mounting public concern about the safety of drinking water”, the region’s water authority has begun testing for PFOS and PFOA at its six water treatment stations.
Hunter Water’s interim chief executive officer, Jeremy Bath, insisted it would be “physically impossible” for Grahamstown Dam to be contaminated “given the direction of the ground water movement”, but said the testing was being done decided “to promote the results as a means of ensuring the community retain confidence in the safety of our water”.
“We know the movement of the ground water and that is south to south-east, Grahamstown Dam is north to north-west from the RAAF Base,” he said.
“It would be like water running up hill.”
But Mr Bath admitted there were no physical barriers around the dam that would stop groundwater leeching in.
“It’s not like a giant swimming pool,” he said. “But, people think that what’s in Grahamstown Dam is what they’re drinking, that’s not true, it’s why the water treatment process is so important.”
Hunter Water representatives will also speak to the Senate committee hearing investigating the spread of the contaminants from the base when it meets in Newcastle on Tuesday.