Biological monitoring of pesticide exposures

Levels of pesticide metabolites in the urine of people known to have been exposed to specific pesticides were compared with the level of these metabolites predicted from data obtained from the regulatory risk assessment process. Cypermethrin and mancozeb were selected as the pesticides to be studied. Subjects were recruited toone of four groups: pesticide applicators or sprayers; agricultural workers entering the fields after spraying (post-application workers); bystanders or neighbours and urban dwellers (consumers). Pesticide metabolites were detected in the urine of sprayers more frequently than in the urine of post-application workers, bystanders or consumers. Recruitment difficulties resulted in a smaller number of samples being obtained than had originally been intended.A simple pharamacokinetic model was developed to predict urinary metabolite levels using dermal exposure level estimated through the regulatory risk assessment process or using data from the EUROPOEM model. Predicted median urinarymetabolite levels were generally much higher than observed urinary metabolite values, for sprayers and post-application workers for both cypermethrin and mancozeb containing pesticides. This provides some confirmation that predicted values are conservative and provides reassurance that the current regulatory risk assessment is protective for sprayers and post-application workers. Where metabolites of cypermethrin or mancozeb were detected in the urine of bystanders, predicted median levels were lower than the observed values regardless of how dermal exposure was estimated. However, only a small number of bystanders were monitored and so it is not possible to conclude whether the regulatory system protects bystanders or not.All measured values for bystanders were well below the acceptable level, i.e. the Allowable Operator Exposure Level (AOEL) or Acceptable Daily Intake (ADI). Since small numbers of subjects were involved, further fieldwork is recommended. We support the establishment of a biomonitoring database as suggested by the Royal Commission for Environmental Pollution and the Advisory Committee on Pesticides. “”