A group of testosterone blocking chemicals is finding its way into rivers that can erode virility and feminize males.
New research has linked water pollution to the rising incidence of male infertility. The study, by Brunel University, the universities of Exeter and Reading and the Centre for Ecology & Hydrology identified a new group of chemicals that act as “anti-androgens”.
These compounds inhibit the function of the male hormone, testosterone, reducing male fertility. Some of these are contained in drugs, including cancer treatments, pharmaceutical treatments and pesticides used in agriculture.
The research suggests that when they get into the water system, these chemicals may play a pivotal role in causing feminizing effects in male fish.
Earlier research by Brunel and Exeter universities has shown how female sex hormones (oestrogens), and chemicals that mimic oestrogens, are leading to feminization of male fish.
Found in some industrial chemicals and the contraceptive pill, they enter rivers via sewage treatment works. This causes reproductive problems by reducing fish breeding capability and in some cases can lead to male fish changing sex.
Other studies have also suggested that there may be a link between this phenomenon and the increase in human male fertility problems caused by testicular digenesis syndrome.
Until now, this link lacked credence because the list of suspects causing effects in fish was limited to oestrogenic chemicals whilst testicular digenesis is known to be caused by exposure to a range of anti-androgens.
Co-author of the study Susan Jobling at Brunel said “we have been working intensively in this field for over 10 years”, according to an Exter release.
Bob Burn, principal statistician at the University of Reading, said: “State-of- the-art statistical hierarchical modelling has allowed us to explore the complex associations between the exposure and potential effects seen in over 1,000 fish sampled from 30 rivers in various parts of England.”
The research was published in the journal Environmental Health Perspectives.