“Similar levels exist in northern inland NSW but less on the North Coast,” Mr Harvey said.

Mr Harvey’s study is now being peer reviewed before submission for publication.

Milton Ulladulla district has been an initial litmus for the State on research indicating elevated levels of neurotoxic lead in our drinking water.

Almost 50 participants from the district took part in his investigations between late last January and October and half of the 55 samples tested contained detectable levels of lead.

On his most recent trip he collected 37 samples from around Armidale and Tamworth in the New England and Macksville and Nambucca Heads on the coast.

“The data continues to tell us a couple of things, the first is that there is a widespread problem with lead entering the consumer's glass of water,” the Macquarie University researcher said.

“The second is that it tells us there is no way to predict where and when elevated lead concentrations will arise.”