Plans by energy firm EDF to dump hundreds of thousands of tons of sediment from the Hinkley Point nuclear power station in the Severn Estuary are facing a backlash.

A campaign group called Save the Severn Estuary, supported by a Welsh pop star, has launched a crowdfunding site to finance a legal challenge.

The estuary is a designated Marine Protected Area and campaigners, including Cian Ciaran of rock band Super Furry Animals, fear the dumped waste, including chemical and radioactive materials, will spread on the strong tidal currents all around the Estuary, depositing on its mud banks and beaches.

EDF, with its UK base in Gloucester, is planning to start its second phase of sediment dumping at Portishead, near Bristol.

Campaigners are calling on the Marine Management Organisation (MMO) to revoke the license granted to the French owned company.

They say without meaningful public consultation the MMO has 'behaved recklessly, treating fishing and ecological interests with utter contempt'. They say the mud is contaminated with radioactive microparticles that could cause cancer and mutations in humans and wildlife.

But EDF says the mud, dredged during the construction process for the new Hinkley Point C reactor, is not dangerous.

Chris Fayers, EDF's head of environment for the project, said: "Hinkley Point C is one of Britain's biggest projects in the fight to protect the environment from climate change. Mud dredging in the Severn is normal practice and extensive testing by the Government's marine science agency, the Centre for the Environment, Fisheries, and Aquaculture Sciences, has shown the mud is safe and poses no risk to the public or the environment.

"An independent report commissioned by the Welsh Government found the mud to be suitable for disposal at sea. We have engaged positively with stakeholders throughout and a public consultation was also carried out."

The Save the Severn Estuary campaign, which claims to be a non-partisan coalition of scientists, experts, individuals and organisations, says: "The MMO must halt the dumping immediately before any further damage is done to the safety and wellbeing of the estuary, its inhabitants and coastal populations of Avonmouth, Bristol, Newport, Cardiff, Barry and beyond."

Campaigners are aiming to raise £60,000 to cover the costs of the legal action.