'Safer' sheepdip is wiping out wildlife, conservationists claim
Unlikely allies from the world of conservation have joined forces in condemning the latest wave of sheepdips which they claim are playing havoc with the ecosystems of Britain's rivers and streams.
The environmental risks of cypermethrin are well-known, and have been openly acknowledged by the authorities.
Environment Agency officers at an April meeting of the South West Wales Area Environment Group told members: "It only takes minute concentrations of a few parts per trillion of cypermethrin to kill some species of invertebrates. "If these are lost it creates a knock on effect for fish which could then die because their food source has gone."
Defra, too, publishes advice to farmers on how to minimise the risk of dip spills, including keeping treated sheep out of water courses for at least two weeks after dipping and making sure the dipping site is well away from any wells, stream or rivers.
According to Buglife, synthetic pyrethroids are replacing the older organophosphate dips because of health concerns, but the new chemicals are 1,000 times more toxic to wildlife than the 'dangerous' ones they are replacing and drips from a treated sheep wading across a stream can kill insects living 10km downstream.
"These chemicals are deadly to aquatic life, the current systems to safeguard our environment have failed," said Matt Shardlow, conservation director of Buglife.
"Only by banning the practice will we be able to halt this unacceptable environmental damage."
The Salmon & Trout Association share Mr Shardlow's concerns and have warned of the impact of the dip on the multi-million pound angling industry.
"Cypermethrin sheep dip pollution is devastating flylife populations across wide areas of the country," said the association's Paul Knight.
"Although the government has brought in a number of measures for the use and administration of sheep dip, even when these best-practice guidelines are adhered to our evidence proves sheep dip pollution still occurs.
"Because the pollution is so toxic to invertebrates any pollution is unacceptable.
"We need to ban cypermethrin sheep dip now."
Acording to EA figures there have been 58 pollution incidents, and four successful preosecutions, related to sheep dip in the past 18 months in England and Wales.
Most appear to have occurred through routine use of cypermethrin.
A spokesman for the EA told edie the agency saw the use of the controversial sheep dip as a very significant problem.
"Our detailed investigations have been mainly in Wales, where a number of particularly devastating pollution incidents have occurred, and because of the concentration of sheep farming," she said.
"Although we haven't looked in detail at the problem elsewhere, we have to assume that the risks exist in other sheep farming areas.
"Much tougher pollution prevention measures need to be pursued, given the implications for animal health and farming of a ban.
"A phase-out strategy whereby alternative approaches are promoted that maintain animal welfare standards and do not affect farmer livelihoods is amongst options we are considering and consulting on."
While its devastating effect on aquatic habitats is recognised, cypermethrin is not thought to be particularly harmful if absorbed by soils and is often used to treat crops as well as livestock.
It is also found in many domestic products designed to kill ants and cockroaches and there are recorded cases of it leading to serious health problems among pest controllers in Germany.
The neurotoxin cypermethrin is thick, yellow liquid or semi-solid that was first synthesised and brought to the open market in the 1970s.
It is classified by the World Health Organisation as moderately hazardous to humans, with some suggestion it could be mutagenic, disrupt hormones and motor skills.
Opinions vary as to whether it is carcinogenic.
By Sam Bond