'Zombie' Hormone Disruptors Rise From the Dead 67
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.'"
Possibly Greatly Overblown (Score:4, Informative)
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/ [missouri.edu]
http://www.ncbi.nlm.nih.gov/pubmed/21438738 [nih.gov]
Sunlight and night? (Score:4, Informative)
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.