Exposure to pesticides of fruit growers and effects on reproduction : an epidemiological approach

In this thesis the exposure to pesticides of fruit growers in The Netherlands was studied as well as its relation to reproductive health effects. The most commonly used fungicide, captan, was used as a marker for exposure. Several exposure studies were carried out during application of captan, and work in the orchards. As exposure per unit of time was in the same order of magnitude for Very different tasks such as application and re-entry, individual time spent on different tasks is crucial for estimating total exposure. As day-to-day variability in exposure was high, within as well as between workers, repeated measurements are necessary to estimate individual exposure accurately. For the application, respiratory exposure was predominantly related to the preparation of tank mixtures. Cabin use on the tractor was the most prominent determinant of dermal exposure during spraying. During re-entry dislodgeable foliar residue was the most prominent determinant of exposure for both respiratory and dermal exposure. Uptake of captan into the human body was measured with biological monitoring of tetrahydrophtalimide in urine of exposed farmers after application. Urine levels were related to dermal exposure of specific skin areas. The consequences of these findings for the way a 'skin notation' is set, is discussed. Another study was carried out to evaluate methods for subjective assessment of pesticide exposure in fruit growing by experts. Experts seem to recognize the most important determinants of exposure. In an epidemiological study time to pregnancy was used to study effects of pesticide exposure. In addition, the relationship with offspring sex ratio was explored. The findings of the study on time to pregnancy indicate that an adverse effect of exposure to pesticides on fecundability is likely. As very few epidemiological studies have been carried out on the effects of pesticides on reproduction, no firm conclusions can be drawn about specific pesticides or other related factors responsible for the observed effect on time to pregnancy or on offspring sex ratio. The indication, however, justifies more attention for possible effects of pesticide exposure on reproduction. In this light, reduction of exposure to pesticides as far as achievable is needed. The validity of the observed effects on reproduction and the underlying mechanisms have to be elucidated.