VITELLOGENESIS AS A BIOMARKER FOR ESTROGENIC CONTAMINATION OF THE AQUATIC ENVIRONMENT

A rapidly increasing number of chemicals, or their degradation product s, are being recognized as possessing estrogenic activity, albeit usua lly weak. We have found that effluent from sewage treatment works cont ains a chemical, or mixture of chemicals, that induces vitellogenin sy nthesis in male fish maintained in the effluent, thus indicating that the effluent is estrogenic. The effect was extremely pronounced and oc curred at all sewage treatment works tested. The nature of the chemica l or chemicals causing the effect is presently not known. However, we have tested a number of chemicals known to be estrogenic to mammals an d have shown that they are also estrogenic to fish; that is, no specie s 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 che micals when tested individually, suggesting that enhanced effects coul d occur when fish are exposed simultaneously to Various estrogenic che micals (as is likely to occur in rivers receiving effluent). Subsequen t work should determine whether exposure to these chemicals al the con centrations present in the environment leads to any deleterious physio logical effects.