Variation in pesticide hazard from vegetable production in Great Britain from 1991 to 2003

Pesticides pose a difficult problem for policy makers as society generally seeks to reduce any adverse impacts of their use, while industry claims they are important contributors to economic success. Attempts to direct policy according to scientific findings are hampered by the multidimensionality of the potential impacts of pesticides which may affect consumers, operators, wildlife and the environment. Pesticide risk indices seek to reduce these multidimensional impacts into a single dimension and have been increasingly used to understand variation in the hazard posed by pesticides at both field and regional level. This study uses one such risk index, the environmental impact quotient (EIQ), to estimate the hazard posed by pesticide usage from 1991 to 2003 on several vegetable crops grown in the UK. Results are reported for the EIQ and for the environmental impact (EI) for brassicas, peas, beans, onions, leeks, lettuce and endives. The EIQ is a dimensionless estimate of the toxicity of a product, while the EI, which combines the EIQ with data on actual usage, estimates the overall hazard of the use of a product. The exact trends in EIQ and EI varied with crop over the period 1991-2003, but overall the EIQ decreased by 19% and the EI decreased by 34%. However, the mean EI per hectare decreased by only 3%. This suggests that some of the observed reduction in EI at the national level may be related more to decrease in crop area than changes in pesticide use and management. If these observed losses in crop area are being replaced by vegetable imports from overseas, then this raises the possibility that the UK is effectively exporting any problems related to pesticide use. The ethics of this remain unclear.