An Environment Agency investigation into Wheal Maid at Gwennap has concluded the former waste tip is contaminated with a range of potentially harmful substances including arsenic, copper and zinc.

Wheal Maid was used in the 1970's and 80's for the disposal of waste from two Cornish tin mines - Mount Wellington and Wheal Jane at Bissoe. The 24-acre site comprises two tailing lagoons and three tailing dams. It is now owned by Gwennap parish council and regularly used by walkers, mountainbikers and motorcycle scramblers.

A serious pollution problem occurred after the two mines closed. An adit poured out contaminated water from a dam into the Carnon River which eventually flowed down into Falmouth where bird and wild life was seriously affected. The Carrick Roads and the bay turned a vivid orange.

The latest findings have come about following Carrick district council asking the Environment Agency to carry out a detailed inspection of Wheal Maid to determine whether the site is contaminated and if the mine waste poses a risk to people using the land for recreation. The Agency was also asked if waste from the site is polluting the St Day stream.

The Agency has worked closely with the Health Protection Agency and the local Primary Care Trust in assessing any risks to users of the site, said a statement issued yesterday.

The investigation showed Wheal Maid is contaminated with arsenic, cadmium, chromium, copper, zinc, lead and nickel. These substances combine in the tailings lagoons to form an acidic leachate which seeps through the lower dam and into the St Day stream.

"Our investigation showed the site does not pose a risk to people walking along footpaths and bridleways or to nearby residents. However, it did indicate health dangers to people regularly using the site for mountain biking. The risks relate to long-term exposure over many years, although even short-term exposure could affect health so the use of Wheal Maid for mountain biking should be avoided," said Martin Weiler for the Environment Agency.

Michael Trevarthen for Carrick council said: "We will work in full co-operation with Gwennap Parish Council, Cornwall county council, the Environment Agency and all other interested parties to secure the best outcome for the site and would advise members of the public to stay off the site."

In the light of these latest findings, the Agency will now make further inquiries to try to find out who was responsible for contaminating Wheal Maid and whether the polluter can be made to clean up the site. If not, other sources of funding will need to be found. Any clean-up could take many years.

In the meantime, Carrick council has been advised to officially classify Wheal Maid a contaminated site and members of the public are strongly advised to keep away from the site until its future has been decided.

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