PESTICIDES IN DRINKING WATER SOURCES AND SUPPLIES (DWE 9004) Final Report to the Department of the Environment June 1987 to March 1993
Report No DWI0301

Aug 1993

SUMMARY

Around four hundred pesticides are approved for use in the UK, and some of these will have the potential to reach drinking water sources. The UK has set a requirement that the concentrations of individual pesticides in drinking water supplies must not exceed 0.1µg/l (0.5µg/l for total pesticides). Pesticides are being found in some water sources and supplies and the subject is one of the more important problems relating to UK water supplies. The research programme covered by this report was aimed at providing information to assist the Drinking Water Inspectorate of the Department of the Environment in providing advice on pesticides to the water industry and other bodies. In addition to pesticides, their environmental transformation products (TPs) may need to be monitored. Also needing consideration are the various non-pesticide chemical present in pesticide formulations.

Pesticides of potential importance were selected for monitoring using various criteria. Multi-residue methods of analysis were developed and these were applied to:

An evaluation of the environmental TPs of the sixty-eight most used pesticides in the UK and the importance of non-pesticide chemicals in formulations were carried out.

Conclusions and recommendations are presented in relation to various aspects of the work including:

  1. The selection of key pesticides and the development of appropriate monitoring methods.

  2. The factors that govern the occurrence of pesticides in water sources, such as usage, seasonal effects and pesticide properties, and models to predict their occurrence.

  3. The potential importance of point sources and,

  4. The relevance of pesticide transformation products and formulation additives.

While the work and findings relate directly to the monitoring and assessment of drinking water quality they also have a bearing on the assessment and protection of river water quality in general.

Copies of the Report are available from FWR, price £35.00 less 20% to FWR Members