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i was just reading this article...

http://news.ninemsn.com.au/article.aspx?id=65741

did anyone know this?

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Truth doesn't always win friends but it influences them

I just read the artical after reading if fully it sounds a political thing rather than any thing else. Notice he did not mention where the research came from or who wrote the paper.

Keith

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Lawrence Springborg will say anything to try and make the leader of the state look bad... He's constantly complaining, and I don't beleive a word that comes out of his mouth. I'd like to see him explain where he got his findings from, but that doesn't make headlines.

i didnt think it was possible that such a large level of hormones could be present in treated sewerage water.. and there is no evidence considering we dont know where the findings did come from..

you gotta love aussie politics!

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Truth doesn't always win friends but it influences them

I heard that yesterday, talk about scare tactics!

I can imagine that it *could* potentially be a problem, but considering the method which they intend to be doing this by, and the fact that many bird sanctuaries and nature reserves are built around recycled sewage, surely this would have popped up well before now.

For animals, the entire universe has been neatly divided into things to (a) mate with, (b) eat, (c) run away from, and (d) rocks. - Terry Pratchett

Ah, this old chestnut.

We've had the issue of what are known as 'oestrogenic compounds' in water arise here in the UK. However, the issue here has centred upon the appearance of compounds with an oestrogenic effect that arise from the decomposition of POPs - persistent organic pollutants - such as pesticide residues and polychlorinated biphenyls generated by the chemical industry (and where I live, we had wall to wall chemical factories for 150 years).

However, those synthetic degradation compounds are also joined by natural oestrogens - women, whether pregnant or otherwise, deliver small quantities of natural oestrogens after each bathroom visit. Not much that can be done about that - it's hardly practical to tell women to stop peeing after all (not to mention likely to provoke some robust responses ...)! Contraceptive pills also play a part here.

There is some respectable research on the subject (here's a link to a PDF from one of our universities) and indeed, certain sensitive fish species will indergo interesting changes after exposure to even small quantities of oestrogenic chemicals. The revelation has also thrown up the fairly interesting matter of metabolites from prescription medicines ending up in drinking water supplies, such as residues from heart drugs and antibiotics. How these are to be dealt with is a matter of ongoing research.

However, the effect is highly variable, and is dependent upon the compounds in question (a compound called EE2 used in female oral contraceptives here in the UK is a particularly potent endocrine disruptor in fishes) and the amounts delivered to the river systems (here in the UK we have human population densities that are considerably higher than in Australia). So the issue is of valid scientific concern.

However, oestrogenic compounds are biodegradable. This means that a suitable treatment system can, in theory, remove them from recycled water altogether, though there are some interesting engineering problems to overcome, along with the ever present looming concern of cost (and who pays for it). That the issue has become a political football says more about those doing the kicking than it does about the issue itself.

Incidentally, the problem isn't "sex changing" - more properly it is termed 'endocrine disruption'. Fishes have reproductive tissues that are remarkably flexible - indeed in many fishes the male and female reproductive systems are anatomically very similar, and the gonadal tissues can respond to hormonal input of either male or female hormones (and of course, there are fishes that DO 'change sex' naturally - Anthias on coral reefs for example). What happens when endocrine disruption takes place is that fishes whose gonadal tissue has been programmed nominally to be male by virtue of genetics, suddenly find their tissues subject to the influence of oestrogenic compounds, and female type oocyte cells (progenitors of eggs) begin to appear in what was originally testicular tissue. There's a nice photomicrograph in the document I linked above illustrating this. Removal of the source of endocrine disruption should, in theory at least, result in the reversion of the testicular tissue to its normal state, though with fishes there are quite a few interesting interactions that are not yet fully understood and are still the subject of Ph.D level research.

Of course, if endocrine disruption takes place in a fish species that exhibits natural and spontaneous sex changing (particularly a protandrous hermaphrodite species) then it's entirely possible that in such a fish, full sex changing would occur. I suspect that the sex ratios of offspring of fishes such as Kribs, whose male/female ratios depend upon, among other things, the pH of the water in which the parents spawned, would also be skewed by endocrine disruptors.

Oh, it's quite a topic of research in respectable ecological circles. The UK government is spending a fair amount of money trying to solve some of the problems that oestrogenic compounds could pose in drinking water supplies. From what I can gather though, given the above, at least one of the two combative Australian politicians is more concerned with grabbing tabloid headlines than listening to respectable scientists (sigh).


Panda Catfish fan and keeper/breeder since Christmas 2002

From what I heard there was a massive long purification chain, essentially getting it to lab-quality pure water before adding it back to the system, and labs aren't likely to want anything other than pure H2O. There was a 6-12 month 'rest' in a natural reservoir too, which I figured would allow the problem material to break down or be taken up by other things (something in the back of my mind is saying 'plants', but that might be backwards and i'm getting it mulldled with phytoestrogens)

And I quite like peeing thankyouverymuch!

Its not like men don't produce oestrogen, whats good for the goose is good for the gander

For animals, the entire universe has been neatly divided into things to (a) mate with, (b) eat, (c) run away from, and (d) rocks. - Terry Pratchett

Well I did say that anyone making that impractical suggestion was likely to face some robust responses Callatya!

It would be interesting to find out how this proposed purification chain works, given that the PDF I linked to notes some interesting engineering and cost problems (at least here in the UK).

The simple fact of the matter is that if we are going to continue enjoying water on tap as and when we want it, we're going to have to recycle our water more efficiently, because simply replumbing the planet isn't going to cut the mustard. Not if we want to maintain that nice biodiversity that is so enjoyable to people like us who keep fish at any rate - but then some of the garganutan replumbing projects that are on the drawing board in some parts of the world are designed more to be corporate money troughs than sensible solutions ...


Panda Catfish fan and keeper/breeder since Christmas 2002