Reduction in male births among workers exposed to metal fumes

Sir—A number of reports suggest that some occupational exposures of males may alter the gender ratio of their offspring. Reduction in male offspring has been observed after exposures to hyperbaric chambers1 and among professional drivers,2 applicators of dibromochloropropane,3 carbon setters4 and aluminum smelter workers.5 Weijin and Olsen6 have suggested that offspring gender ratio, because of its correlation with reduced fertility, may be a possible epidemiological indicator of reproductive hazards. We have conducted a study to evaluate the possible role of exposure to metal fumes (particularly nickel and chromium) on the reproductive health of male workers in an Italian mint. The study was designed to evaluate specifically fertility problems, and the observed reduction in fertility is reported separately. We also noted, however, an interesting alteration of the gender ratio with reduced male births which we feel is worth reporting. The workers were divided into administrative staff (non-exposed to metal fumes), technical and maintenance staff (with minimal exposure), coin stampers (exposed to metal fumes) and founders (highly exposed to metal fumes). Air sampling and biological monitoring of workers yielded concentrations of metals within the TLV-ACGIH. However, the blood nickel levels were very near the biological reference value of 0.5 μg/dl, especially among founders.