And going sterile:
NO ONE EVER planned for fish to take birth control pills. But they are. As treated wastewater flows into rivers and streams every day, fish all over the world get a tiny dose of 17Î±-ethinylestradiol, a synthetic steroidal estrogen that’s used in birth control pills. They also get a little sip of the anticonvulsant carbamazepine, a nip of the antidepressant fluoxetine, and a taste of hundreds of other drugs that we take to make our lives better.
Let’s face it – we are a society obsessed with drugs, pharmaceutical and otherwise. Also, increasingly so, we are a society obsessed with keeping our bodies free of toxins. Conflict of interest much? The fish think so. Male fish inhabiting waters near water treatment plants, for example, are becoming feminized (aka growing eggs in their testes) as a result of our habits.
By far, the most dramatic example of this kind of pharmaceutical pollution has been the effect of estrogenic compounds on fish. In the 1990s, scientists working in the U.K. noted that male fish living downstream from wastewater treatment plants were becoming feminized. They were making proteins associated with egg production in female fish, and they were developing early-stage eggs in their testes. Feminized male fish have now been observed in rivers and streams in the U.S. and Europe.
Recent studies done by John Sumpter, an ecotoxicologist at England’s Brunel University and Karen A. Kidd, a biology professor at the Canadian Rivers Institute, University of New Brunswick, confirm that the level of pharmaceutical drug contamination in the waters is affecting the fish. The drugs are getting there via several paths (see image below) – in our bodily excretions, and through our drains (I know all you ninjas have flushed a little something down your toilets at some time or another). The levels are low – as low as the parts per trillion (ppt) range, but because drugs are specifically formulated to be effective at low levels, even the ppt range can affect the water populations.
FOR THREE SUMMERS, Kidd and her colleagues spiked a lake in Canada’s Experimental Lakes Area with 17Î±-ethinylestradiol at a concentration of 5 pptâ€”a concentration that has been measured in municipal wastewaters and in river waters downstream of discharges. During the autumn that followed the first addition of the estrogenic compound, the researchers observed delayed sperm cell development in male fathead minnowsâ€”the freshwater equivalent of a canary in a coal mine. A year later, the male fathead minnows were producing eggs and had largely stopped reproducing. The minnow population began to plummet. The decline continued for an additional three years until the fish had all but disappeared from the lake.
And as the circle of life goes, the loss of one species ripples through the food chain:
The fathead minnow wasn’t the only fish to feel the effects of the trace amounts of birth control. The population of lake trout, which feed on smaller fish, fell by about 30%. “The numbers of lake trout dropped not because of direct exposure to the estrogens but because they lost their food supply,” Kidd says.
But Kidd’s story is not all doom and gloom. In 2006, three years after her team stopped adding 17Î±-ethinylestradiol to the lake, the fathead minnow population rebounded. “So given enough time, once you remove the estrogens from a system, the fish can recover to their original population size,” Kidd notes.
People and animals excrete pharmaceuticals and their metabolites, which then find their way into the environment through a variety of routesâ€”treated wastewater, agricultural runoff, and biosolids and manure that are used as fertilizers. Pharmaceuticals also enter the environment when people dispose of medications by flushing them down the toilet or pouring them down the drain.
We cannot avoid the bodily excretion of drugs that make it through our systems, but we can use other means of disposing of unused drugs. C&EN recommends:
Getting people to stop flushing away their unwanted medication is one easy way to cut down on pharmaceutical pollution. So last year, the Office of National Drug Control Policy (ONDCP) issued new federal guidelines for the proper disposal of prescription drugs. According to the guidelines, unused, unneeded, or expired prescription drugs should be removed from their original containers and thrown in the trash.
To prevent accidental poisonings or potential drug abuse, ONDCP recommends mixing meds with an undesirable substance, such as coffee grounds or kitty litter. The mix should be placed into impermeable, nondescript containers, such as empty cans or sealable plastic bags, before being tossed in the trash.
In some cases, the risk of poisoning or abuse outweighs the potential environmental impact. The Food & Drug Administration recommends that certain controlled substances, such as the painkillers OxyContin and Percocet, are best disposed of down the drain. A full list is available at ONDCP’s website (whitehousedrugpolicy.gov/drugfact/factsht/proper_disposal.html).
Moral of the story: stop flushing your goods. And check C&EN for more details.