DETERMINANTS OF EXPOSURE TO CAPTAN IN FRUIT GROWING

A series of studies investigated occupational exposure to pesticides a mong fruit growers in The Netherlands during spraying and reentry of o rchards between 1990 and 1992 to identify and quantify determinants of exposure. Determinants of exposure are discussed as a starting point for hazard identification and control. Captan was used as a marker for exposure. Cabin use on the tractor was the most prominent determinant of derma[ exposure during spraying. For respiratory exposure, factors related to preparation of pesticides were most prominent. A long dura tion of exposure may reflect a different exposure situation compared w ith a short duration of exposure. As different determinants of exposur e prevailed for each subgroup, consideration should be given to constr ucting exposure models for each group separately. Dislodgeable foliar residue (DFR) was the most prominent determinant of exposure for both respiratory and dermal exposure during reentry. However, no significan t relation between DFR and dermal exposure of forehead and sternal are a was found, perhaps because there was no direct contact-with foliage here. Therefore, use of a transfer factor based on DFR to estimate tot al dermal exposure is only a crude estimate. The half-life of captan o n crops varied from 10-17 days, so substantial exposure when entering the orchard is very likely, particularly when spraying frequency is hi gh. The main starting points for reduction of exposure are use of a ca bin, DFR, and individual time spent on different tasks. Determinants t hat are constant over time (cabin use) may have an especially great in fluence on grouping workers, according to long-term exposure in epidem iological studies. As determinants of exposure vary for the different exposure routes and body locations (for dermal exposure), the measure of interest for a specific study design will decide which determinants are most relevant.