Yorkshire Water cleared in River Calder cyanide fish kill

An investigation has cleared Yorkshire Water of any part in a pollution incident in the River Calder on 5 July. The source of the pollution, identified as having consisted of least 30kg of cyanide, has not been traced.


“We have definitely eliminated Yorkshire Water from having been involved,” an Environment Agency spokesperson told edie. The cyanide is thought to have been discharged illegally into the public sewerage system in Todmorden and then passed through Yorkshire Water’s sewage treatment works at Eastwood, Todmoren.

The cyanide-tainted water was then released from the sewage treatment plant into the Calder river and resulted in the death of more than 300 trout.

A joint investigation between Yorkshire Water and the Environment Agency has led to the conclusion that the cyanide was probably a mixture of copper and potassium cyanide. Such a substance is used in the copper electro-plating industry.

Commenting on the joint effort between Environment Agency and Yorkshire Water in determining the cause of the fish kill – originally thought to be the result of an ammonia discharge by Yorkshire Water – the EA spokesperson said that working together had proved useful, despite the fact that the exact origin of the cyanide has not been traced.

Any member of the public with information regarding this incident is urged to contact either the Environment Agency on 0645 333 111 or Yorkshire Water’s Industrial Waste Team on 0845 124 2429.

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