Many years ago I had a conversation with my sister, who's a highly qualified nurse and academic instructor. We were discussing the problems of drugs taken in combination with one another: that while one drug may be perfectly safe in and of itself, when combined with another drug, or dietary supplement, its effect may be negated, or even turned into something negative.
My sister pointed out that this was even more of a problem in nature. There are tens of thousands of chemical compounds developed over the past century or so: medicines, fertilizers, manufacturing chemicals, plastics and polymers, and so on. These have all leaked out into nature, whether by deliberate discharge, negligence over their disposal, breakdown of products containing them, even human waste products discharged into sewage systems. She said that what worried her was that all these tens of thousands of compounds were now interacting in nature in ways that have never been tested in any laboratory. How do we know what some of the new combinations may do?
One very worrying answer has just been reported in Britain.
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.'
The article lists a number of potential contributors to the problem:
- Bisphenol A (BPA): Oestrogen-mimicking chemical found in clear plastic bottles, food containers, dental sealants and the lining of food cans.
- Phthalates: Oestrogen mimicking plastic softener used in toys, PVC, flooring, shower curtains, and air fresheners.
- Polybrominated Diphenyl Ethers: Flame retardant used in casing of computers and TV's, furniture, lighting and carpets. Mimics oestrogen.
- Oestrogen: By-product of contraceptive pill and hormone replacement therapy. It enters environment by sewage.
I wish the scientists investigating this the best of luck. I'd hate to be part of the generation that condemned the human race to extinction with our own effluent! The alleged threat of human-caused 'climate change' may be 'chump change' by comparison.
Peter
3 comments:
This was news here in the states at least 10 years ago. Of course it was just a blip on the radar and disappeared very quickly
That explains Boy George.
We need to check San Fransisco's water STAT.
I'm not convinced. Too many of the studies are done without proper experimental design and control of the factors involved.
It's a little like the anthropogenic global warming stuff, where a particular opinion has become expressed as fact because of consensus among a vocal group of scientists instead of compilation of data.
The Bisphenol A studies (for example) have so far been inconclusive because they haven't controlled for other possible factors. Mind you, I'm not saying that it isn't harmful, I'm just saying that we need to do a much more thorough job of testing its influence. The environmental scientists who get funding are not the ones who want to study small, controllable effects (the kind where you can prove causation, for instance), but the gloom-and-doom types who can claim that their research will save the planet (and thus, being broader in scope, are more difficult from which to draw accurate conclusions).
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