Gender-bending chemicals in our
rivers grow more potent
By David Derbyshire
2:19 AM on 19th January 2009 Dail Mail UK
Pollution
horror: Anti-androgens in poisoned fish can induce low fertility and an
increase in genital deformities
The cocktail of gender-bending
chemicals entering rivers and streams is more potent and harmful than anyone
realised, it has been revealed.
Scientists have found an entirely
new class of chemicals that is changing male fish into females – and which
could be contributing to the soaring rate of infertility and defects in men.
They have yet to find the source
of the chemicals, known as anti-androgens, but believe they could come from
pesticides, industrial pollution or pharmaceutical drugs.
Until now it was assumed that the
most serious gender bending man-made chemicals were those that mimicked the
female sex hormone oestrogen.
The new pollutants, which were
discovered in more than 30 rivers, work by blocking male sex hormones such as
testosterone. In animal tests they have shown to cause low sperm counts and
genital deformities.
Professor Charles Tyler, of
Exeter University who was involved in the study, said the mix of anti-androgens
and oestrogen mimicking chemicals was a 'double whammy' for wildlife – and
possibly humans.
'There are likely to be many
reasons behind the rise in male fertility problems in humans, but these
findings could reveal one, previously unknown, factor,' he said.
'Anti-androgens can induce a lot
of conditions we see in humans, such as low fertility and an increase in
genital deformities, very readily.'
People could be exposed to
anti-androgens in pesticides on food, through airborne pollution or from drugs.
The findings come from a three-year study at Exeter and Brunel Universities.
Scientists looked at samples of
water from 30 sites near sewage outlets and at 1,500 fish. Genetically
engineered yeast cells can be used in a laboratory to determine levels of
anti-androgens. The researchers were astonished at what they found.
Male fish exposed to the highest
levels of anti-androgens were most likely to be 'feminised' – and have egg
cells in their testes.
Dr Susan Jobling of Brunel
University, said: 'We have identified a new group of chemicals, but do not know
where they are coming from. A principal aim of our work is now to identify the
source of these pollutants and work with regulators and industry to test the
effects of a mixture of these chemicals.'