An estimated 200 million litres (equivalent
to the contents of 450 municipal swimming pools) of sheep dip is disposed of
each year from around 50,000 dipping facilities. Data from the Soil Association
suggests that dips from about 2,000 facilities are discharged directly into
water courses, and over 25,000 operators use the soakaway method of disposal
where chemical is allowed to soak into the ground near to the dip facility.
Sheep dip is generally used by immersing the sheep in baths holding 2,000-2,500
litres of dip solution. These baths may be emptied in a number of ways:
directly emptying via a drain hole into water courses;
via a soakaway constructed adjacent to the dip bath allowing the spent dip to soak into the ground;
by being pumped out and spread onto surrounding farmland;
if the dip is mobile, the used dip can be disposed of elsewhere (in some cases the contents of fixed dip-baths may be removed in this manner).
Although the Ministry of Agriculture, Fisheries and Food (MAFF) apparently holds such information as part of its agricultural census data gathering, there are no official publicly available figures as to the number, the location, the type or the condition of sheep dipping facilities in the UK.
The chemicals used
Three organophosphate (OP) active ingredients:
diazinon, chlorfenvinphos and propetamphos accounted for 75% of dips sold at the
time of the initial Soil Association research. Since then it is likely that
farmers have increasingly switched to synthetic pyrethroids. At present
therefore, the probable ratio of OPs to synthetic pyrethroids used is about
50:50.
High pollution risk
The most detailed study to date carried out by the
Tweed River Purification Board (TRPB) in Scotland found damage to river
ecosystems downstream of the disposal of OP sheep dips. The study found:
a pollution risk at 40% out of 795 sheep dip facilities investigated;
at 31 sites (5%), dip operators discharged used dip directly into a water course;
disposal in 50% of cases involved soakaways (against MAFF advice see below);
awareness of farmers about the pollution potential of sheep dip was 'extremely patchy';
in some cases, spent dip was entering watercourses at hundreds of times the proposed Environmental Quality Standard (EQS), particularly for the OP propetamphos;
in one incident in 1995, a cupful of spent dip (containing the synthetic pyrethroid cypermethrin) entered a river and killed 1,200 fish downstream.
EC action on groundwater pollution
The UK government is currently subject to infringement proceedings from the
European Commission over a complaint about groundwater pollution from OP sheep
dip. This decision reflects the Commission's concern that groundwater
resources should be fully protected in accordance with Council Directive
80/68/EEC. As a result, the Commission says there is inadequate application of
the Directive in relation to sheep dip disposal.
Inconsistent and impractical advice
Currently, advice to farmers is contradictory, and the
preferred method of disposal is prohibitively expensive. The Veterinary
Medicines Directorate (VMD), which provides official advice, suggests sheep
farmers dispose of dip by incineration through a reputable specialist waste
contractor. Soil Association research found that very little information was
available from waste authorities on how to follow such instructions. On the rare
occasion a contractor was identified, the costs of disposal averaged £1,000 per
bath of dip.
There is conflicting advice with regards to soakaways (the
next best option after incineration). The latest recommendation of the
Veterinary Products Committee (VPC) of the VMD states: "While soakaways should
not be generally recommended for disposal, they might be deemed safe in certain
circumstances." This appears to contradict MAFF's Code of Good Agricultural
Practice for the Protection of Water which states: "Soakaways are not suitable
in most places as they could pollute groundwater." As an alternative, the Code
advises: "Spread used dip onto land at low application rates." Yet, the VPC
admits this latter strategy is a compromise based on economics and expediency,
not on environmental good practice.
The VPC concluded: "The recommendation to spread dip wash
onto a suitable area of land was agreed after much heart searching and only
because there did not appear to be a viable alternative for farmers."
Doing without dips?
Organic sheep farmers have developed husbandry
strategies to minimise or do without the use of chemicals to control sheep
scab or problems from fly-strike.
Organic sheep farmers are however permitted to use limited
amounts of the synthetic pyrethroid flumethrin to control sheep scab, which
therefore means some disposal issues are as relevant for organic as for
conventional sheep farming. The Soil Association has carried out a number of
surveys among organic sheep farmers because of concern over this issue. Two
conclusions can be drawn. First, it is possible to manage sheep organically
without the use of dipping, given the right conditions and a sufficient level of
husbandry. Second however, flumethrin may be advantageous, or even necessary, in
some circumstances and it is clear that organic farmers are then faced with
equal problems when disposing of the spent dip. In response, the Soil
Association has introduced a requirement to mix the spent dip with slaked lime
28 days before disposal, as the increase in pH has the effect of neutralising
the flumethrin.
Recommendations
Patrick Holden, director of the Soil Association,
concluded: "Our research confirms that sheep dip disposal represents one of
the least monitored and controlled farm pollution hazards. Neither the
(previous) government or the manufacturers have provided farmers with the means
or advice to dispose of them safely."
As a result of these concerns the organisation recommends:
MAFF should provide the Environment Agency (that monitors for pollution) with details of the location and type of all sheep dipping facilities in the UK. This information could be collected as part of existing agricultural census and payments information gathering.
Sheep dipping should be made a notifiable act, where farmers have to give advance notice of dipping to the Environment Agency.
The disposal via soakaways of OP sheep dips should be prohibited.
All existing dips using the soakaway method should be closed down within two years, or converted into non-soakaway disposal methods.
Dip manufacturers should subsidise incineration of sheep dips so that proper disposal is affordable to farmers.
MAFF should encourage and support organic sheep farming.
Sheep Dip Disposal: No room for
complacency, Soil Association, Bristol House,
40 - 56 Victoria Street, Bristol,
BS1 6BY, Fax, +44
(0)117 925 2504, 1997, £9, 33pp. (Researchers: Karen McVeigh, Dervila
O'Brien, John Skelton, Consultants: Dr Gordon Halliday and John Newton,
Production: Tim Weisselberg)
Robin Maynard is Local Campaigns Director
at Friends of the Earth and was formerly Campaigns Director at the Soil
Association.
[This
article first appeared in Pesticides News No. 36,
June 1997, page 11]