Evaluating risk from insecticide use at the field and regional scales in Iran

Abstract

Approximately 50% of all pesticides registered in Iran are insecticides with potential risk to human health and the environment. The environmental impact quotient (EIQ) is a pesticide risk indicator that was used to rank the inherent risk of 48 insecticides in use in 28 Iranian provinces and evaluate their environmental impact (EI) at the field and provincial scales over three growing seasons from 2001 to 2005. The results indicate that the introduction of new insecticides over the past decades has produced a negligible decrease in inherent risk. About 75% of provinces had low EI scores of 0.62–11.3. The highest EI and EI/ha scores were found in Kerman and Mazandaran provinces, mainly from increased usage (amount of active ingredient) rather than increased toxicity of insecticides. Inherent toxicity (EIQ) was not significant for increased EI in contrast to the increase in pesticide usage. On average, diazinon comprised 37% of total usage, carbaryl 12.2% and teflubenzuron 8% of total usage. The toxicity of these insecticides ranked lower for EIQ. In contrast, the total usage of environmentally high-risk insecticides (imidacloprid, fipronil, lindane) was relatively lower during the study period. Overall, the increased use of insecticides was not related to the increase in the area under cultivation, but to the type of crop grown (pistachios, vegetables) and to inappropriate spraying equipment and inadequate storage practices, both of which are common problems in developing countries.