Salmon and Trout Association: Sheep Dip

Cypermethrin sheep dips are toxic insecticides designed to kill parasites, but in concentrations as low as 1 part per billion, they cause devastation to aquatic invertebrate populations, and also damage the reproduction and juvenile life stages of salmonids.

There are four main areas of concern regarding the use of sheep dips: 1. the poisoning of rivers and the wipe out of invertebrates from sheep dip pollution; 2. harmful effects of the polluting sheep dip chemicals on the breeding, development and fitness of salmonids; 3. damage to terrestrial ecosystems when sheep dips are ‘disposed of’; and, 4. potentially devasting public health risk given the harmful effects minute amounts of the chemical have on salmonids.

In the 2004 Environment Agency (EA) Wales study, 100% of the stream sites sampled exceeded the Environmental Quality Standard (EQS) for sheep dips. EA and CEFAS research records cypermethrin in rivers exceeding the EQS by as much as 400%, and that this pollution puts the survival of threatened stocks of fish and invertebrates at risk.

In February 2006, the Veterinary Medicines Directorate (VMD) suspended the marketing licence on cypermethrin, particularly thanks to S&TA lobbying. This marked a significant milestone in fisheries NGO influence over environmental issues.

The argument for continued use of sheep dip is animal welfare. This is an important and serious issue, as is good animal husbandry and disease and drug resistance prevention. But already there are sheep mites and ticks resistant to sheep dips - leading to increased concerns about sheep farming’s damaging chemical dependency problem. Since the suspension, there has been no evidence of any decline in animal health as a result.

Meanwhile, new Government commissioned research shows one sheep crossing 3 inches of water a few hours after being dipped in cypermethrin can poison 2,500 meters of a stream, and exceed, by 25 times, the Maximum Allowable Concentration (MAC) of the (EQS) for cypermethrin pollution. Even two days after being dipped, one sheep stepping through a stream 3 inches deep causes enough pollution within 300 meters to seriously reduce Atlantic salmon and brown trout reproductive efforts and drastically lessen the survival chances of embryos and smolts. The study states the risks of surface water pollution from a single sheep could continue for several months after dipping.

The EA and VMD commissioned an ‘options appraisal study’ to advise them on either permanently banning cypermethrin or bringing it back onto the market with management conditions.

S&TA’s view is that only by eliminating sheep dip pollution will the Government meet its legal duties to protect, maintain, improve and enhance the environment – including fisheries. There is no question in S&TA’s view that the most effective way of ensuring these duties are met is to ban cypermethrin and organophosphate sheep dips, and support the alternatives.

We now have to continue the fight until cypermethrin is banned permanently in favour of the viable alternative sheep treatments already available to farmers.

---

For further information see:

• S&TA Information Sheet
• S&TA. (2007). Sheep Dip Letter to EA Chief Exec
• S&TA. (2007). Comments on GHK report and VMD research reports
• S&TA. (2006). Targeted Sheep Dip Pollution Monitoring
• S&TA. (2006). Sheep Dip Pollution Reduction Programme
• Central Science Laboratory. (2007). Cypermetrin losses from sheep farms
• EA. (2007).An appraisal of the options for responding to the risks and impacts associated with sheep dip products.
• Public Cypermethrin Suspension Notice (2006).
• Defra. (2006). Pesticides and the Environment.
• Sustainable Control of Parasites (2005). Ectoparasite Control in Sheep
• EA. (2004). Effects of sheep dip disposal on terrestrial invertebrates.
• RFERAC. (2005). Sheep dip impact on aquatic life.
• EA. (2002). Proposed Environmental Quality Standards for Cypermethrin and Flumethrin in water.