Endocrine Disruptors in Freshwater: Impact on Teleost Reproduction

Fish are acutely affected by the increasing number of chemicals in the ambient water, including endocrine disruptors (EDC’s). EDCs include heavy metals such as cadmium and mercury, the polycyclic hydrocarbon benzo(a)pyrene, polychlorinated biphenyls, phthalates, carbamate and organophosphate pesticides, organochlorines, and bisphenol A. Nevertheless, certain groups of EDCs do manifest a comparatively greater effect on specific endocrine glands. The endocrine dysfunctions induced by explicitly acting EDCs include changes in fertility and in the ratio of male and female fish, classified as xenoestrogens or xenoandrogens. These EDCs result in a high prevalence of intersex condition including sex reversal. Feminization of male and masculinization of female fish pose a serious threat for fish populations, causing reduction or even breakdown of the reproductive performance of fish and of the yield of fisheries. It is now widely accepted that fish provide reliable biomarkers of early effects of EDC’s which data can be used as a warning signal for the ecosystem in general and a lever to diminish or prevent further release of effluents and discharges from anthropogenic activities. Graphic Abstract