26 June 1998

Towards sheep dip


Pollution caused by sheep

dip recently cost a

Staffs farmer £6064 in fines

and costs. Robert Davies

looks at ways of avoiding

such incidents

THE arrival of synthetic pyre-throid dips, which are 100 times as toxic to invertebrate aquatic life than organo-phosphorous compounds, set alarm bells ringing at the Environmental Agency.

Bob Merriman, the Agencys rural land use officer responsible for monitoring water pollution and enforcing legislation, admits he is worried about the risk of major incidents involving the economically important rivers flowing through areas with high sheep populations.

"Invertebrates are an essential link in the food chain of some incredibly valuable fishing rivers that contribute £millions to the rural economy," says Mr Merriman. "But many are in areas where sheep density, soil type and topography increase the risk of pollution."

His fears have been magnified by detailed inspections of dipping facilities in some river catchment areas. These revealed dip baths located too close to streams, facilities in very poor condition and some with drain holes to ditches, inadequate drain pens and dip chemical being disposed of in soakaways.

"If these findings are representative of the rest of the country then several thousand dips urgently need attention. At present the Agency does not have any power to serve a notice to prevent pollution if we see a system represents a significant risk of pollution."

But advice can be offered and failure to respond is likely to increase the chance of court action should an incident occur in the future.

Mr Merriman and his colleagues make much of their readiness to consult and work with farmers, but they can, and frequently do, prosecute offenders.

They also have the means to trace the source of any pollution and the statutory right to charge the polluter for the scientific detective work involved.

Unlike incidents involving slurry or silage effluent, very small quantities of SPs and even OPs may have no apparent effect on vertebrates. Though millions of tiny animals have been killed the water course can seem sparklingly clean.

Biologist Lucy Morris is based at the Agencys laboratory at Shrewsbury. She is often called on the follow the trail of dead invertebrates over many miles to the point where the pollution occurred.

"There may be no colour change, frothing or smell, but all insects and many other invertebrates are wiped out. By taking samples we can always follow the pollution route. In one case the trail was 10 miles long and the polluter had to pay for every sample taken and analysed."

The offender can also be fined up to £20,000 and face large legal and compensation bills. Mr Merriman acknowledges that the sheep industrys financial pressures make farmers reluctant to spend on improving dipping facilities. But he insists that a pollution incident costs very much more.

"I am working with farming organisations to get the message across that just the washings of dip chemical off gloves and other protective equipment are sufficient to pollute a stream for hundreds of metres."

Michelle Bannister and Sharon Kirman are environmental protection officers based at Shrewsbury and have been visiting farms in one catchment area with dipping practice questionnaires. They have also been asking permission to check facilities.

"The majority of farmers are very co-operative and very conscious of their responsibilities," says Ms Bannister. "If we see a problem that needs addressing we will point it out then and write later. We have seen cracked baths, dips with illegal drains, the use of soakaways against best current advice, drain pens from which chemical runs into ditches and systems where sheep have to walk through a stream after dipping."

Ms Kirman says less obvious pollution incidents are often discovered when a member of the public notices an absence of insect life or an angler reports that fish have migrated from a stretch of water. Even when contamination occurred several weeks before the source can and will be found.

Mr Merriman suggests that all flockmasters should carry out self- assessments of their dipping systems. Based on a questionnaire developed by the Agencys north west region, it involves giving 18 yes or no replies. A single positive reply should prompt remedial action.

The dip bath must be at least 10m (33ft) from any water course, or 50m (166ft) from a spring. It should be of one piece construction. Drain holes should be permanently sealed and not "plugged with a polythene bag and a wooden bung". Leaks must be repaired effectively.

Draining pens must have impermeable surfaces, and all run off liquid should return to the bath. Dippers should have a valid NPTC certificate of competence.

Freshly dipped sheep should not return to pasture via a road or track that passes through a watercourse, or drains to one. The grazing area must not have access to water courses or wetlands and drinking water must be provided.

Mr Merriman says safe spent dip chemical disposal is vital and should be planned in advance. Soakaways are not acceptable. Dilution and spreading onto land must be very carefully managed. Steep, underdrained or waterlogged land should not be used, Neither should areas close to streams and springs, or wildlife habitats. A mixture of one part spent dip to three parts water can be spread.

Dipping pollution – risks self-assesment

Dipping facilities

Is the facility within 10m of any watercourse or 50m of a spring?

Does the dip bath have any drain holes, even if plugged?

Is it suspected of leaking?

Does the facility have a dry well with a drain hole?

Are impermeable drain pens missing?

Does some pen drainage not return to the dip bath?

Can splashes escape from the bath?

Is the dip bath prone to overflowing in wet conditions?


Do any operators lack a valid NPTC certificate of confidence, or similar?

Management of freshly dipped sheep

Do sheep return to pasture via a road or track that drains to a watercourse?

Do they pass through a watercourse?

Are sheep release to pasture allowing access to watercourses or wetlands?

Used dip disposal

Do you propose to dispose of used dip:

To a soakaway?

To land which is steeply sloping, underdrained or waterlogged?

To land within 10m of a watercourse, or 50m of a spring?

To land important to wildlife ie. a hedgerow, woodland or moorland?

Do you propose to spread at an application rate exceeding 5 cubic metres/ha?

Any yes replies indicate a high risk of pollution in the event a slight mishap

See more