≡ Menu


Wild fish in the freshwater, estuarine and coastal sea environments of are undoubtedly affected by chemical pollution that can cause hormone disruption. Particular attention has been drawn to sewage treatment plant effluents, which contain hormonally active compounds ranging from naturally occurring steroids and manmade steroids used in the contraceptive pill, through to industrial chemicals.



The best-known effect is the feminising of male fish. When exposed to some hormone disrupting chemicals in the wild, juvenile and adult male fish, including roach, gudgeon and rainbow trout, start to abnormally make the  egg yolk protein, known as vitellogenin, and can even start producing female eggs in their testes.  The findings of a UK Government DEFRA-led study, published in December 2002, confirmed that vitellogenin production was still occurring in male flounder in estuaries, particularly the Clyde, Mersey, Tees and Tyne.

CHEM Trust’s report Effects of Pollutants on the Reproductive Health of Male Vertebrate Wildlife – Males Under Threat by Gwynne Lyons, shows that male fish, amphibians, reptiles, birds and mammals have been harmed by chemicals in the environment. Widespread feminisation of male vertebrate wildlife is highlighted. These findings add to mounting worries about the role of hormone-disrupting or so-called ‘gender-bending’ chemicals in the environment, and the implications for human health.