#4 While seemingly innocuous, this has the potential to become a substantial problem. Phthalates found in plasticizers (used in Saran wrap, can liners and many flexible plastics) are now being connected to increasing "intersex" (mingled genital formation) populations in fish, alligators and other wildlife. Pseudo-estrogenic compounds found in food packaging and those excreted by human birth control users may be altering the sexual expression of other species. These compounds, known as hormone-mimics are being identified as "endocrine disruptors" which may affect the gender outcome and genital formation of some wildlife. There are ongoing investigations into connections between these chemicals and the global decline of human sperm counts.
Phthalates, largely used as plasticisers, have long been suspected in connection with rising infertility rates, particularly among men. These substances are quite common and are considered highly hazardous to human health because they disrupt the hormonal balance and impair reproduction and development.
In this same vein, increasing quantities of excreted anti-depressants now appearing in our waterways may have unanticipated effects upon the behavior of wildlife. These psychoactive compounds may cause subtle alterations in mating behavior and breeding patterns. The PPB and PPT concentrations sound negligible, but much higher levels may be present at sewage processing outfalls and waste disposal facilities.
In the short term studies, the antibiotics and cholesterol drug at concentrations of just 10 parts per billion appear to stunt growth and result in more male offspring. In the long term studies, these differences were diminished: offspring exposed to the antibiotics tended to have longer lifespans, while those exposed to the cholesterol lowering drug showed no apparent effects.
Exposure to the antidepressant produced no differences in the shorter trials, but did result in a greater number of offspring in the longer studies. "When Daphnia were exposed to a single pharmaceutical throughout their entire [30 day] life span, as in the long term studies, they seemed to become acclimated to the polluted environment," Flaherty said.
When Flaherty exposed the organisms to a combination of the cholesterol drug and the antidepressant during the short term studies, up to 90 percent of them died. Their offspring were more likely to be female, and to have deformities that hinder swimming.
EMPHASIS ADDED
While it is premature to sound alarms over this issue, it certainly merits close attention. A more significant problem lies in how our populations are increasingly medicated in daily life. The potentially negative downstream effects of altering brain chemistry with powerful neuro-chemical drugs may take decades to manifest fully. |
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