The effects of ethylene dibromide on semen quality: a comparison of short-term and chronic exposure

Two occupational field studies were conducted to determine the effects of ethylene dibromide (EDB) exposure on male reproductive potential. The first study was a longitudinal study of 10 EDB-exposed forestry employees and 6 unexposed men conducted in Colorado in the summer of 1983. The exposure time was approximately 6 weeks. The second study was a cross-sectional study of 46 EDB-exposed papaya workers and 43 unexposed men conducted in Hawaii in December 1983 in which the average term of employment was about 5 years. In the longitudinal study, sperm velocity decreased in all 10 exposed men and in only two unexposed men. Semen volume was also decreased in 9 of the 10 exposed men (there was no change in the other man); only two unexposed men had a decrease in their semen volume. The longer term EDB exposure resulted in decreases in sperm motility and viability, suggesting that the short term exposure may slow sperm velocity, but longer exposures cause immotility and cell death. An apparent decrease in semen volume that was observed in the longitudinal study was not statistically significant in the cross sectional study of workers having chronic exposure. However, a significantly higher semen pH was observed in the exposed men compared to the unexposed men in the cross-sectional study. The results from both studies suggest that the accessory sex glands may be affected by EDB exposure.