A North Yorkshire farmer this week claimed he is facing an environmental disaster after tests revealed that 81ha (200 acres) of his land is contaminated with toxic heavy metals he believes were left during the recent flooding.

David Dean said that tests on grass and soil samples taken from Hill Top Farm, Acaster, Selby, had revealed high levels of metals, including zinc, nickel, lead, arsenic, cadmium, copper and mercury.

Mr Dean, whose land is close to the confluence of the Rivers Ouse and Wharfe downstream of York, sent the samples to Lancrop Laboratories in Pocklington after grass and hay in his fields started dying shortly after the flood water receded.

He said the land affected included all his winter feed and grazing and that he had now had to bring his 200 cattle into sheds to feed them after being warned that the levels of zinc could cause them to suffer liver and kidney problems.

Mr Dean believes the metals were left in untreated sewage discharged from the nearby Naburn sewage works and is seeking compensation from the Environment Agency, which he holds responsible. “I don’t blame the EA for the flooding, but it’s their job to keep the rivers clean – and they haven’t done that in this case,” he said.

Mr Dean said that he had contacted both the Environment Agency and DEFRA, but neither had offered any help. “They’ve put the shutters up,” he said. “They are all passing the buck. I’m facing an environmental disaster, the levels of heavy metals are way beyond the maximum permitted levels – and my fields are dead.

“There needs to be an investigation into how this has happened. I have been farming here since 1965, and the land has flooded many times, but this has never happened before.”

A spokeswoman for the Environment Agency said: “We have received copies of Mr Dean’s lab test results and will be looking at the figures, but there are natural traces of metals like lead in the Ouse.”

A spokeswoman for Yorkshire Water said that the operation of the Naburn sewage works had not been compromised by the June floods and that “at no time did any untreated sewage find its way into the river”.

A DEFRA spokeswoman said that contamination of farmland was a matter for the local authority.