THE Environment Agency is investigating a pollution incident that took place on March 26th on the River Crouch near Wickford in Essex.
A report was made to the Environment Agency that a dead salmon or sea trout had been removed from the River Crouch at Battlesbridge Mill.
Investigations by the Agency showed that a raised level of ammonia was present in the river water, but that there was no reduction in dissolved oxygen and fish did not appear to be suffering.
Anglian Water also contacted the Agency to advise that there had been an unforeseeable reduction in treatment performance at the Wickford sewage works and that steps were being taken to minimise any environmental impact of this.
Investigations found that unauthorised contaminated trade effluent had been discharged to the sewage works from an unknown source. A substance in the trade effluent had reduced the performance of the bacteria in the sewage works which treats ammonia, resulting in the ammonia in the effluent exceeding the consent limit.
Further investigation by the Agency on the following days showed that ammonia levels in the effluent discharge from the works had returned to normal. Samples were taken from the river at various points showing that ammonia levels had also returned to normal with no evidence of dead fish.
Both the Environment Agency and Anglian Water are continuing to investigate the source of the pollution. The Agency takes pollution incidents extremely seriously and will always prosecute where appropriate. Any member of the public witnessing a potential pollution incident should ring the Agency’s emergency hotline number on 0800 80 70 60.