The agency said Marina Development Limited (MDL), which plans to convert the Newlyn site into a marina, hotel and housing complex, would be required to carry out its own tests and submit the results with the planning application.

MDL has disputed recent claims that the pool of water, which will mix with sea water if the marina development goes ahead, could be highly toxic.

Terry Cotton has suggested that the water could do "untold damage to marine life".

But Geoffrey Waldon, a mining geologist for MDL, said the company had tested the water and had no concerns about the quality.

"It's not highly acidic," he said. "Its the same quality as any other stream coming off this coast."

* The water in the quarry occupies a space of four hectares.

article copyright THE CORNISHMAN