A rapidly increasing number of chemicals, or their degradation products, are being recognized as possessing estrogenic activity, albeit usually weak.
We have found that effluent from sewage treatment works contains a chemical, or mixture of chemicals, that induces vitellogenin synthesis in male
fish maintained in the effluent, thus indicating that the effluent is estrogenic. The effect was extremely pronounced and occurred at all sewage
treatment works tested. The nature of the chemical or chemicals causing the effect is presently not known. However, we have tested a number of
chemicals known to be estrogenic to mammals and have shown that they are also estrogenic to fish; that is, no species specificity was apparent.
Many of these weakly estrogenic chemicals are known to be present in effluents. Further, a mixture of different estrogenic chemicals was
considerably more potent than each of the chemicals when tested individually, suggesting that enhanced effects could occur when fish are exposed
simultaneously to various estrogenic chemicals (as is likely to occur in rivers receiving effluent). Subsequent work should determine whether
exposure to these chemicals at the concentrations present in the environment leads to any deleterious physiological effects. - Environ Health
Perspect 103(Suppl 7):173-178 (1995)
Key words: vitellogenesis, fish, estrogenic contamination, water quality