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'Zombie' Hormone Disruptors Rise From the Dead
ananyo writes "Hormone-disrupting chemicals may be far more prevalent in lakes and rivers than previously thought. Environmental scientists have discovered that although these compounds are often broken down by sunlight, they can regenerate at night, returning to life like zombies (abstract). Endocrine disruptors — pollutants that unbalance hormone systems — are known to harm fish, and there is growing evidence linking them to health problems in humans, including infertility and various cancers 'Risk assessments have been built on the basis that light exposure is enough to break down these products,' adds Laura Vandenberg, an endocrinologist at the University of Massachusetts in Amherst who was not involved in the study. 'This work undermines that idea completely.'"
I assume that there simply weren't as many endocrine disruptors in the wild, so it was less of an issue over evolutionary time; but for (modestly complex) chemicals to be photosensitive enough to degrade; but suitably structurally favored to have more than a remote probability of being created by the recombination of their breakdown products is rather interesting...
Would it be in any way adaptive for hormones themselves(which disruptors are often very similar to, hence the ability to neatly disrupt the endocrine system) to have this level of durability, or is it much more likely that it's mere chance, biologically irrelevant until we started pumping the things out on an industrial scale?
Chemicals are your friends. Untested chemicals are your untested friends.
There a lot of serious problems with doing risk assessment for endocrine disruptors.
The first is that there is no known mechanism for most of the effects reported in the literature. Without this mechanism a real science based approach is impossible.
The second issue (and a general problem for that matter) is that many of the studies reported turn out not to be reproducible.
The following articles give some insight into this, relative to BPA which has been (possibly without justification a cause celebre):
http://munews.missouri.edu/news-releases/2013/0102-previous-studies-on-toxic-effects-of-bpa-couldn%E2%80%99t-be-reproduced-says-mu-research-team/
http://www.ncbi.nlm.nih.gov/pubmed/21438738
The other day I caught a bit of a documentary on the zombie craze. It ended with the head of some zombie research institute saying something along the lines that deep down, they view the zombie appocolypse as a metaphor for any disaster, manmade or natural. The same tactics, supplies, and training you need for a zombie outbreak can also be used to survive another hurricane Katrina.
Zombie survival fantasies are also about the most tactful way to work through your serious interest in gunning down shambling hordes of your abhuman inferiors, without attracting social condemnation or law-enforcement interest.
This is not to say that all zombie enthusiasts are doing this, many are indeed, harmless LARPer types who are guilty only of perhaps not knowing when a premise is no longer amusing; but if you do happen to suspect that the Racial Holy War is looming, and negroid looter swarms will emerge from their slums to march on the exurbs any day now, a little fretting about 'zombies' is a good way to get your feet wet without making yourself a total pariah in polite company.
Expecting "none at all naturally" is not realistic. OTOH, having lots more of the chemicals, whether combined or not, in the streams and lakes is a problem iof they are endocrine disruptors.
;-)
It's like global warming. We need carbon dioxide. But too much of a good thing is too much.
I find it interesting that the default assumption of everyone looking at chemicals is that they break down and then never recombine.
Unlike trees in a forest, chemicals apparently combine whether anyone is watching or not. (It's too hard to see at night
Kind of makes you wonder if the breakdown products from this stuff can get into your body separately, and then combine there. Well, it makes me wonder. Maybe that's because I'm not a biologist, or maybe it's because I'm a pessimist.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Well here is what gets me... if they break down in sunlight, but then recombine without the light, well.... natural bodies of water tend not to be terribly clear. You don't have to go down far to not find all that much light, especially if the area itself isn't in direct sunlight....
So its likely that in many place, it doesn't even take "night", breakdown is likely only happening within a short distance of the surface.
"I opened my eyes, and everything went dark again"