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How Estrogen From The Pill Could Be Deadly For Fish

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The effects of contraceptives on waterway ecosystems has been both explored and debated for decades - and a recent ongoing study may hold some of the answers.

Lead researcher Karen Kidd of the University of New Brunswick and a team of researchers have been conducting a study at a freshwater lake research facility in northwestern Ontario, Canada since the late 1990s. Kidd says the study began after researchers in the United Kingdom discovered that male fish started to produce eggs when estrogen was introduced to their environment. Kidd's team wanted to build upon this observation, and determine if there were larger effects on the lake's ecosystem and if the presence of estrogen would inhibit the fathead minnow's ability to reproduce.

The testing at the facility involved introducing small amounts of synthetic estrogen (EE2) used in birth control pills, which can be classified as endocrine-disrupting chemicals (EDCs), into the lake and observing the effects of the hormone on the freshwater fish living in the water reserve. Kidd said in a statement that "Right away, the male fish started to respond to the estrogen exposure by producing egg yolk proteins and shortly after that they started to develop eggs ... They were being feminized."

After the estrogen was introduced, the number of fathead minnows in the lake declined rapidly. Says Kidd, "The crash in the population was very evident and very dramatic and very rapid and related directly to the estrogen addition."

Meanwhile, the number of insects around the ecosystem increased, presumably due to lack of predation from the minnows. According to the study, the decline in minnows directly affected the fish who were higher up on the food chain. The team writes that the "biomass of top predator lake trout declined by 23–42% during and after EE2 additions, most probably an indirect effect from the loss of its prey species, the fathead minnow and slimy sculpin."

Once the estrogen was removed from the ecosystem, the number of fathead minnows surged once more to the pre-study population size.

Kidd told CTV News that feminized male fish have been observed in Saskatchewan's Wascana Creek, Ontario's Grand River, and Alberta's South Saskatchewan River. These attributes are likely due to sewage being released into the waterways. "It's a problem that we can certainly resolve with better waste water treatment," she says.

Prof. Sue Jobling, the Head of the Institute for the Environment, and Richard Owen, from the University of Exeter, wrote a piece in 2012 entitled "Environmental science: The hidden costs of flexible fertility." This piece endeavored to examine the effects of contraceptive chemicals on rivers, estuaries and lakes, as well as discussing the regulation of these chemicals. The authors state that "The need to protect our environment from the harmful effects of (EDCs) is clear, but understanding of our willingness as a society to pay for that protection is not. Nor is it obvious where responsibilities lie, including whether pharmaceutical companies have a moral duty of care for all their products, which could be better designed so that they are safe for the environment."

ACS' journal Environmental Science & Technology found that birth control pills account for less than one percent of the estrogen found in drinking water, and that there is actually a greater presence of natural estrogens, such as those that come from dairy products and animal waste. Additional research from the study suggests that animal manure accounts for 90% of estrogen in the environment.

Kidd and the rest of her research team in Ontario concluded their study by writing that such small-scale studies are unlikely to be as conclusive as necessary in this matter. The team writes that whole-ecosystem experiments will inevitably be more effective in "understanding indirect effects of EDCs and other aquatic stressors."

When it comes to the disposal of old prescription medication, the U.S. Food and Drug Administration advises against flushing any pills down the sink or toilet, unless the drug label specifically advises you to do so. The FDA recommends mixing the pills with an undesirable substance, such as used coffee grounds or kitty litter (to deter anyone from recognizing or taking the drugs), before placing the mixture in a sealable bag or container and placing it in the trash.