When a new synthetic substance is created, or a naturally occurring substance is generated at greatly increased levels, the effects can be far longer-lasting and wider-reaching than its manufacturers predict or intend. Some well-known examples of this include asbestos, a popular insulation and flame retardant in the late 19th century, which was later discovered to be carcinogenic; and polystyrene foams like Styrofoam, which is frequently used in disposable packaging, yet takes hundreds of years to break down once discarded. In the case of oral contraceptives, the key ingredients are synthetic hormones known as progestins, which mimic progesterone, either alone or combined with estrogen. When used therapeutically in contraceptive pills or in hormone replacement treatments for menopause, these synthetic hormones make their way into the water supply after being excreted in the patients’ urine. As environmental contaminants, these are referred to as endocrine-disrupting chemicals (EDCs), due to the fact that they interfere with the endocrine systems of humans and animals alike following exposure.
While its impact is still being widely studied, there is no doubt that the exposure is occurring: multiple international studies have documented elevated levels of natural and synthetic hormones in drinking water, and one such study conducted in France noted that progestins in particular were more resistant to removal by water treatment methods, compared with other types of pharmaceuticals (3).
Due to the accumulation of synthetic steroids in water, much of the research conducted on its impact has been done using water-dwelling vertebrates such as fish and frogs. An ever-increasing collection of studies report harmful effects of these hormones on aquatic vertebrates, particularly with regard to their reproduction, as would be predicted given the nature of the contaminants (4). One study focused on the effects of exposure to the progestin Levonorgestrel (LNG) on the frog Xenopus tropicalis. While the male reproductive system did not appear to be impaired, female tadpoles exhibited severe defects in the development of their ovaries and oviducts, rendering them sterile (5).
Saturday, May 19, 2012
Contraception As Hurtful For Environment as Asbestos and Styrofoam
Something to think about.