Chemical leak in Witney stream kills 1,700 fish

Environment Agency staff are focusing on a 2km stretch of Colwell Brook and Queen Emma's Dyke

About 1,700 fish have died in a suspected chemical leak in a stream.

"High ammonia levels" were found in the water near Witney Lake, said Thames Water, due to discharges from a nearby sewage treatment works.

It said the cause was "most likely substances being put into the drainage network which shouldn't be there".

The Environment Agency (EA) said officers were taking measurements from rivers and monitoring fish levels.

Dog owners warned

A spokesman said: "The Environment Agency is investigating the death of about 1,700 fish on a 2km stretch of Colwell Brook and Queen Emma's Dyke near Witney Lake in Oxfordshire.

"Investigations are ongoing and officers are on site, taking measurements from local rivers and conducting a fish survey, with an ecology survey planned for tomorrow."

Members of the public used social media to warn dog owners to protect their pets from entering the water yesterday.

The Spotted Witney Official Facebook page said Thames Water staff were testing the water after "some sort of chemical/pollution spill into the river".

Sewage discharges

A Thames Water spokeswoman said it was working with the EA to prevent further environmental damage.

"We've identified high ammonia levels in the stream which we believe are due to discharges from our sewage treatment works," she said.

"We're investigating what has caused these discharges to contain such high ammonia levels, most likely substances being put into the drainage network which shouldn't be there, and are supporting the Environment Agency in their work to protect the stream from further damage."

Graham State, who runs a nearby tackle shop, said it was not the first time there had been pollution incidents in the area.

"We've had it happen several times in the past, but not for a few years. The river's changed colour in the past."