In Cumbria alone, about 90 miles of river have been damaged by the new synthetic pyrethroid (SP) sheep dips leaking into the water.
The chemical wipes out most of the tiny aquatic insects, crustacea and other invertebrates near the base of the food webs. This starves the fish and that, in turn, deprives otters and river birds of their fish food. Streams have also been harmed in upland areas of the West Country and Wales.
SP dips have been marketed as a safer alternative for ridding sheep of parasites than the organophosphate dips which have caused severe, chronic illness in many farmers. Sales have soared over the past five years. But according to the Environment Agency, they are up to one hundred times more lethal to river life, and a teaspoonful entering a stream can wipe out invertebrates for hundreds of metres downstream.
Farmers are currently asked to follow a Code of Good Practice when they dispose of surplus dip. This allows them to pour it onto flat grassland, provided it is at least 10 metres from any river and 50 metres from any well or borehole.
But the European Commission reckons this is inadequate, and is prosecuting Britain for failing to comply with EU water pollution laws. The Government has responded by promising new regulations covering the disposal of waste dip, to come into force next year.
When these are issued the agency expects to be put in charge. Farmers wishing to dispose of dip on their land will have to get its permission. If there is any risk of dip reaching a river, this will not be granted.
The agency's pollution prevention manager, David Griffiths, told a sheep farming conference yesterday: ``We will not hesitate to prosecute where there is evidence that farmers have caused pollution.''
Both coarse and game fishermen are calling for the SP dips to be withdrawn. They can also cause problems when the wool from dipped sheep passes through processing and cleaning plants - their effluent can harm rivers. The Environment Agency is talking to the textile industry about tackling that.
Grampian Pharmaceuticals, which sells most of the SP dip in Britain, said that provided the instructions accompanying the product were followed there should be no damage. It had sent details of the Code of Practice to all 8,000 of its customers.Reuse content