Determination of operator exposure levels to insecticide during bait applications in olive trees: Study of coverall performance and duration of application

In this study the operator exposure levels during bait applications of an insecticide in olive groves were determined using a whole body dosimetry method for dermal exposure. The study design allowed the roles of application task duration and coverall type to be evaluated as factors influencing operator exposure. Twenty applications were carried out with knapsack sprayers in the Tanagra region of Viotia, Greece, ten of which were for a 1 h and ten for a 3 h duration. An in-house GC-NPD analytical method was developed and validated for the determination of malathion, the active substance (a.s.) of the insecticide formulation used in field trials. The mean recovery of field-fortified samples was 84% (%RSD = 3.0). Field trial results generally indicated lower operator exposure levels than indicated by the most relevant operator exposure predictive model. Residues of malathion on internal dosimeters were compared to those measured on the respective outer coveralls (potential dermal exposure) to evaluate the protective factor of each one of the two coverall types used. Both coverall types provided satisfactory levels of protection and can be considered as suitable protection for the conditions of the application scenario studied. Furthermore, the results indicated that there is not a strong correlation between exposure levels and duration of application.