Levels of toxicity in the river have been reducing steadily since Saturday as rain and flowing water continued to dilute the chemical residue and the EA report that levels are now undetectable in the river in Peterborough.

Crustaceans are the most sensitive species to pollution in the river and levels in the Nene are below what would be expected to affect them.

Norman Robinson from the Agency said:

“The exact number of dead fish is still being assessed but is likely to now be in excess of 4,000. The pollution has also wiped out a large percentage of invertebrates along the stretch of affected river between Orton Mere and Wisbech.

Our biological surveys have shown there is likely to be a long-term impact on the flora and fauna of the river. We are now working out how to help the river recover.”

Tens of thousands of fish were seen in distress along the length of affected river after the 5,000 litre chemical spill from Safapac at Orton Southgate industrial estate.The Environment Agency managed water flows between Orton Mere and the Dog in a Doublet Sluice to help dilute the chemical pollution and lower the risk to wildlife.

The chemical spill is still being investigated by police and the Environment Agency and people are advised to take the usual precautions when being in contact with river water such as covering up cuts and not swallowing the water.