22 June 2001

Treat used sheep dip, says DEFRA

USED sheep dip must be treated before disposal to reduce the risk of spreading foot-and-mouth virus, according to new advice issued by the Department of Environment Food and Rural Affairs.

There is a possibility that used dip solution contains foot-and-mouth virus, it says. But it can be destroyed by increasing the pH to 11 or more for 30-60 minutes.

Which method to use to increase pH will depend on the type of dip used. The first option is to check whether the manufacturer can supply a deactivation pack containing a strong alkali, advises DEFRA.

When this is not available, add 5kg of powdered lime for each 100 litres of used dip containing diazinon or flumethrin. This must be mixed thoroughly for five minutes to ensure that the pH is raised sufficiently. Sodium hydroxide should be used instead of lime for dips containing high cis-cypermethrin.

Increasing the pH of sheep dip will have no additional effect on the environment, says Bob Merriman of the Environment Agency. "Disposal on land can be undertaken within existing authorisations for land disposal, but they will need to be amended by contacting your regional office."

Apply used dip on land, spread it thinly over a level site, at least 10m (33ft) away from watercourses and 50m (165ft) from springs and wells, he says.

When disposing of dip, DEFRA recommends spreading it on-farm to reduce virus transfer between farms. For this, producers without authorisation can still apply for permission from their local Environment Agency office. &#42