The NSW Environment Protection Authority (EPA) is investigating the extent of a fluoride discharge into Slaughterhouse Creek and the Williams River from the Dungog water treatment plant in Dungog, on Tuesday.

EPA manager Hunter Region, Adam Gilligan said the EPA was alerted to the discharge by Hunter Water.

“The EPA has begun an immediate investigation into the circumstances leading up to the discharge and has taken a number of water samples,” he said.

“The EPA understands that Hunter Water has contacted all downstream landholders who might be using the Slaughterhouse Creek to water stock or agriculture and alerted them to possible pollution of waters.”

Slaughterhouse Creek runs through a number of rural properties on the outskirts of the Dungog township, then into Williams River.

While fluoride is considered safe in small quantities, it can be toxic at high concentrations.

“Hunter Water has been discharging large volumes of water to the creek since the incident to dilute the fluoride and has been conducting its own monitoring until levels return to normal,” Mr Gilligan said.

“The water quality data received by the EPA on Wednesday suggests there were initially high levels of fluoride in Slaughterhouse Creek.

“Levels have shown progressive reductions as the creek is being flushed.

“Anyone with health concerns arising from the incident is encouraged to contact their GP for further advice.

“We should have further sample results back later today (Thursday).”

Anyone with any concerns about water quality is encouraged to contact the EPA’s Environment Line on 131 555.