Blue stream in Harlow to be investigated by Environment Agency
An investigation is under way after a stream turned bright blue.
The discoloration of Canons Brook in Harlow, Essex, happened over the weekend.
A farm nearby said it was not the first time it had happened, and it was "very concerning" as the stream was a water source for crops, and children and pets played in it.
The Environment Agency said it was investigating but it had no evidence of harm to the wildlife.
Elliot Wollen, manager at Herts and Essex Community Farm, said: "It's a really vivid blue, you can't miss it at all and if you follow the brook down, it goes as far as you can see.
"This brook leads into the River Stort, so it's contaminating a huge area with this unknown substance."
He said it was not an isolated incident and on previous occasions it has turned yellow, pink and red.
Mr Wollen said the farm used the water from the stream for crops.
"When contamination like this happens it's really worrying and also for our wider community," he said.
"Children play in these streams, people walk their dogs and they go into the water... it leads down to the River Stort and there's an outdoors pursuits centre where they are running holiday clubs at the moment."
He said the farm had stopped using the water from that part of the brook and had moved upstream to extract water.
The Environment Agency said: "Our specialist officers are investigating how Canons Brook in Harlow turned blue over the weekend, but thankfully have no current evidence of harm to wildlife or the environment."
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