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Fish don't want birth control, but scientists say they get it from your pill

WASHINGTON — Your birth control pill is affecting more than just your body.

Flushed down toilets, poured down sinks and excreted in urine, a chemical component in the pill wafts into sewage systems and ends up in various waterways where it collects in fairly heavy doses. That's where fish soak it up.

A recent study by the U.S. Geological Survey found that fish exposed to a synthetic hormone called 17a-ethinylestradiol, or EE2, produced offspring that struggled to fertilize eggs. The grandchildren of the originally exposed fish suffered a 30 percent decrease in their fertilization rate. The authors mulled the impact of what they discovered and decided it wasn't good.

“If those trends continued, the potential for declines in overall population numbers might be expected in future generations,” said Ramji Bhandari, a University of Missouri assistant research professor and a visiting scientist at USGS. “These adverse outcomes, if shown in natural populations, could have negative impacts on fish inhabiting contaminated aquatic environments.”

The study, with Bhandari as lead author, also determined that the chemical BPA, used widely in plastics, had a similar effect on the small Japanese medaka fish used for the research. The medaka was chosen because it reproduces quickly so that scientists can see results of subsequent generations faster than slow reproducing species such as smallmouth bass.

BPA and EE2 are both endocrine disrupters that interfere with hormones and cause developmental disorders. Over the past 12 years, male smallmouth and largemouth bass throughout the country have switched sex, developing ovaries where their testes should be, and the two disrupters are prime suspects.

These particular chemicals were employed in the study for good reason. EE2 is a major ingredient in oral contraceptives for women, and up to 68 percent of each dose is released in the latrine through urine and excrement. A full dose is released when some women simply pour unused pills down the drain.

BPA is a chemical used primarily for polycarbonate plastics and epoxy resins. Environmental waste from products containing it “has been a serious concern and potential threat to public and wildlife health,” according to a USGS statement about the study. It was published recently in the journal Scientific Reports.

Gender-bending is happening at several locations on the Potomac River in the Chesapeake region, showing up in between 50 and 100 percent of bass caught and dissected. EE2 survives even after wastewater is treated, so it's a safe bet that large doses arrive when sewage facilities dump millions of gallons of untreated wastewater into the Potomac and other waterways during overflow events when pipes are overwhelmed by rain.

“We know intersex is occurring, we don't understand exactly how that's occurring,” said the recent study's co-author, Don Tillitt, research toxicologist at USGS's Columbia Environmental Research Center in Missouri. “We know that certain endocrine disrupting chemicals can cause intersex from exposure during development or the birth cycle.”

Japanese medaka were used for a study showing the harmful effects of birth control pill residue that contaminates waterways. Ramji Bhandari and Ben Stahlschmidt/USGS
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