An intensive field trial and a multi-site surveillance exercise on the use of aldicarb to investigate methods for the assessment of possible environmental hazards presented by new pesticides

Abstract

The opportunity presented by the introduction of a coal-based granular formulation of the carbamate nematocide, aldicarb for use on sugar beet and potatoes in the United Kingdom has been used to evaluate a number of new methods for the assessment of the environmental hazard presented by pesticides. In an intensive field trial with sugar beet, well established biological procedures for recording changes in animal populations and behaviour were combined with a planned programme involving the sampling of animals, plants and soil. Emphasis was placed on sampling and observing mammals in addition to birds which have been more extensively studied in the past. The samples were submitted to a variety of chemical and biochemical analyses designed to reveal the extent to which the pesticide was distributed temporally and spatially and the effects it produced on individuals. The results indicate that although the pesticide is not persistent, it is mobile especially in wet soil, systemic in plants and can be found widely in the local vertebrate fauna for up to 90 days after application. Specific hazards were identified as arising from the ingestion of uncovered granules and from worms containing residues coming to the surface following application in wet conditions.

Subsequently a surveillance exercise was mounted on the commercial use of the pesticide at eight sites where sugar beet and potatoes were grown. The hazards identified in the field trial were confirmed and their practical importance assessed, resulting in modifications to the application method in order to eliminate them.

The value of the various methods employed in the trials and the significance of the results are discussed. It is concluded that the approach used will find wider and more general use in assessing the environmental hazard posed by new pesticides.