An Epidemiological Evaluation of the Biochemical Basis for Steroid Hormonal Depressions in Fish Exposed to Industrial Wastes

Our earlier work showed that exposure to bleached kraft pulp mill effluent resulted in a number of reproductive alterations in white sucker including depression of circulating sex steroid hormone levels. Further studies demonstrated that reductions in the steroid biosynthetic capacity of the ovarian follicle were responsible for these changes. In this study an epidemiological approach was used to evaluate whether fish (white sucker and brown bullhead) exposed to different classes of organic compounds (non-chlorinated pulp mill effluent and polycyclic aromatic hydrocarbons) exhibit comparable alterations in reproductive function (reduced gonadal size, reductions in circulating steroid levels and depressed steroid biosynthetic capacity). The criteria of probability, strength of association, and consistency with respect to time were satisfied with respect to these reproductive alterations. The responses observed did not satisfy the criteria of specificity, or consistency with respect to different people and were indeterminate for the criteria of prediction, time order, consistency with respect to different places, species and contaminant as well as for coherence. In conclusion, changes in reproductive performance represents a common response in fish exposed to pulp mill effluent and other organic contaminants, but the biochemical basis for steroid hormone depression in fish associated with organic contaminant exposure is not consistent enough to allow generalizations at this time.