HEATHROW is to blame for thick slime in the River Crane, but campaigners have been assured it should not affect the waterway’s recovery from a huge sewage release.
De-icer used on planes and runways during this winter’s extended cold spell has leaked into the river, according to the Environment Agency, causing a build-up of fungus.
The latest incident comes nearly a year-and-a-half since a huge volume of sewage was released into the river by Thames Water in October 2011, to prevent it backing up into Heathrow, killing at least 10,000 fish.
When supporters of the river, which runs through Cranford, Feltham and Whitton, spotted dead fish and a layer of grey sludge in its lower reaches this month, they were naturally concerned.
But the Environment Agency, which has been working closely with Heathrow to improve water quality in the Crane, this week assured nature lovers the river was expected to recover quickly.
A spokesman for the eco watchdog said high levels of the de-icer glycol, used at Heathrow, had leaked into the river, encouraging bacteria to grow. He insisted the same effect would occur had naturally-occurring substances like milk or orange juice got into the water.
“We are aware of grey fungus and continue to monitor the water quality of the River Crane,” he told the Chronicle. “Grey fungus is not harmful to humans or pets and the fungus is expected to naturally dissipate over the coming weeks. We have taken samples and await the results.”
He added that Heathrow had an existing treatment system and was developing a series of upgrades in consultation with the Environment Agency.
Friends of the River Crane Environment (FORCE), a charity set up to protect the river and its surroundings, said members first noticed a ‘green tinge’ to the water of the lower Crane early last month.
Reports had intensified this month, with one walker capturing pictures of polluted water and dead fish at an outfall by Heathrow and another finding a thick layer of slime.
There had been promising signs of the river’s recovery before Christmas, when 5,500 fish were released into the water, aided by the £400,000 pledged by Thames Water.