Risk evaluation of the reproductive effects of chemicals acting on the nervous system in the occupationally exposed population

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We evaluated the reproductive function of workers exposed to pesticides acting on the nervous system. A questionnaire survey was conducted on 54 males of a pesticide company, asking the workers their subjective symptoms and the sex ratio of their offspring. Of them, the following indices were measured for 34 workers ; the serum concentrations of testosterone, follicle stimulating hormone(FSH) and luteinizing hormone, the time-weight average of exposure concentrations, and the urinary concentrations of metabolites of the insecticide and solvents. Semen indices of six workers were examined according to the WHO manual. Urinary bromide ion concentrations, a metabolite of an organohalogenated pesticide, were significantly higher in the exposed workers than in the controls. The solvent concentrations were almost comparable with the general population except for toluene (2.5-13.5 ppm) and ethyl acetate (1.5-7.3 ppm), indicating that they were below the occupational exposure limits. No signifi … More cant differences were observed as to that of the workers' offspring and their sex ratio. A significant positive correlation was observed between the age of the workers and the FSH concentration. Semen indices were within normal limits, but the participation ratio was only 11.5%. As a whole, it is unlikely that there is any significant toxic effect on the reproduction of the workers.Another semen study on pesticide sprayers revealed a significant increase in sperm with lower motility compared to the non-exposed controls in summer when pesticide-spraying work is at maximum. However, there was no positive biologically relevant finding for other indices. Thus, we administered dichlorvos, suggestive of a testicular toxicant, to male rats for 9 weeks. The results showed a significant but small increase in the percentage of motile sperm at doses inducing marked inhibition of acetylcholine esterase. We could not conclude that the observed effects in the workers were attributable to dichlorvos exposure alone. Less