The trade body Water UK estimates that removing pesticides from drinking water down to the EU limit of 0.1 micrograms per litre costs water companies £100 million per year. It blames diffuse sources such as run-off from roads, railways and farmland.
The industry has long insisted that the large sums it spends on removing pesticides fit uncomfortably with the "polluter pays" principle. It has also argued that the simplest solution to persistent pesticide contamination of smaller sources is to abandon them - a practice unlikely to be sustainable in the longer term in view of growing pressure on water resources.
Eureau's report gives the problem a European perspective. Data from 17 countries show that the UK has one of the worst problems - with 77% of surface water and 6% of groundwater sources "regularly" exceeding the 0.1µg/l limit. However, many countries lack adequate information for comparison (see Table 1).
Eureau says there are certain pesticides which "give rise to significant contamination of water resources however carefully they are used" - and which "should be severely restricted or even banned." It lists ten products which it considers to cause the most common problems, including glyphosate - widely considered to be relatively environmentally benign (Table 2).
Several of the problem pesticides are already listed as "priority substances" under the 2000 EU water framework Directive (ENDS Report 312, pp 46-47 ). Environmental quality standards and other measures to achieve a progressive reduction in discharges are to be drawn up for these by the European Commission. Eureau wants to see pesticides breaching drinking water limits given priority in the process.
But Eureau acknowledges that best practice schemes can be effective. These include catchment protection agreements with landowners, integrated crop management, spraying agreements with Railtrack, and training programmes. However, it says the results can be "of very limited value" without high participation.
The European Crop Protection Association commented that calls for pesticides to be banned were "counter-productive". It favours a local or regional approach which allows products to remain in use in areas where they do not pose environmental problems.
ECPA said that water quality improvements would be achieved only if the sources and activities were identified and addressed through improved farm management, voluntary agreements and collaborative approaches.