Drug Pollution

EVERY TUESDAY, at 11 AM, C&EN's news staff gathers to select the items that will populate the five pages making up the News of the Week section of the magazine. In our deliberations for the issue of Nov. 12, 2007, one item for consideration was advice from the federal government on proper disposal of unused medicines.

In particular, the Substance Abuse & Mental Health Services Administration, which is part of the Department of Health & Human Services, was encouraging Americans to mix leftover medicine with used kitty litter. The story idea elicited much laughter. I thought it was a joke.

The story idea didn't land in the news pages, but an item in the Government Concentrates page explained what some of us dismissively laughed about: "The goal of [mixing with kitty litter, coffee grounds, or sawdust] is to prevent the drugs from falling into the hands of those who might abuse the agents" (C&EN, Nov. 12, 2007, page 39).

No joke after all, the federal agency's advice raised serious questions: What pharmaceuticals are in the environment and in what amounts? How do they affect the environment? What happens to unused medicines? Do people know how they should be disposed of? This week's cover story (page 13), by Associate Editor Bethany Halford, offers answers.

All kinds of drugs are in the environment—antibiotics, antidepressants, anti-inflammatory agents, birth control agents, you name it. "People and animals excrete pharmaceuticals and their metabolites, which then find their way into the environment through a variety of routes," Halford writes.

"If you're a fish, it's really bad," Halford tells me. For example, at very low concentration, 17α-ethinylestradiol, a synthetic estrogen used in birth control pills, feminizes male fish, and some feminized males don't reproduce. A population of fathead minnows, which Halford says are "the freshwater equivalent of a canary in a coal mine," rapidly declined when researchers temporarily treated their habitat with the estrogen at 5 ppt, she reports.

To us humans, however, the more immediate question is the effect on our health. Opinions vary. Several of Halford's sources think that the concentrations of pharmaceuticals finding their way into drinking water are too low to cause health effects. However, according to Christian G. Daughton, chief of the Environmental Chemistry Branch at the Environmental Protection Agency's National Exposure Laboratory, toxicologists have yet to understand the effects of simultaneous exposure to multiple chemicals, each at low concentration. But all agree "that more research needs to be done on all aspects of pharmaceuticals' effects in the environment," Halford finds.

Detection is no longer a problem. Advances in analytical instrumentation and techniques now enable detection of exceedingly low concentrations of pharmaceuticals in the environment. What scientists must figure out next is what really makes sense to measure. Halford reports that it's not enough to look at the parent compounds only; their breakdown products could be equally disruptive to the environment. And it's not enough to look at compounds individually; they could be interacting with other contaminants.

What actions should the data spur? Whether sewage treatment plants should be engineered to remove pharmaceuticals is controversial; doing so would be extremely costly, Halford reports.

Individuals, however, can help reduce pharmaceutical pollution now. According to Halford, "Pharmaceuticals also enter the environment when people dispose of medications by flushing them down the toilet or pouring them down the drain." Flushing of the medications of deceased people alone adds an estimated 19.7 tons of active pharmaceutical ingredients into U.S. sewage systems annually, she reports.

So next time you're poised to flush medications, stop. Heed the advice of the U.S. government: Mix them with unpleasant material such as used kitty litter, coffee grounds, or sawdust, and put the mixture in a can or plastic bag before tossing it in the trash. Better still, make use of pharmaceutical take-back programs, which take unwanted medicines and incinerate them.

Views expressed on this page are those of the author and not necessarily those of ACS.