Pharmaceuticals in our Drinking Water

On Monday, one of the cover stories in the Express (a publication of the Washington Post) announced the alarming discovery of “six commonly used drugs” in the District of Columbia’s water supply. The discovery was the result of a study by the Associated Press, which found that pharmaceuticals were present in the water supplies of at least 41 million Americans. The drugs discovered in DC water included caffeine, naproxen, and ibuprofen. In many other cities across the nation other drugs, including sex hormones (from drugs like birth control and Viagra), were also found.

Reading this article made me very angry. Unlike the average express reader, I was not angered by the news that the water I drink could be harmful to my health; I had accepted that long ago. I was furious that what should already be common knowledge was presented as new, and that a public that should be better informed instead reacted with such surprise. I have known for years that our over-medicated species has been poisoning our waters, ourselves, and wildlife. I was disappointed that the AP article was narrowly focused on the effects these drugs could potentially have on human health, with only passing mentions of the well-documented ill effects drugs in small concentrations have on wildlife around the nation.

If you perused any of the articles covering this story, you will have read that when we take medications, ANY medications, the body does not metabolize the entire dose. What is left exits the body and enters the water cycle. Pharmaceuticals (as well as many other dangerous or toxic compounds such as flame retardants) enter the water system despite wastewater treatment, because current wastewater treatment practices do not remove them. A 2004 study by the U.S. Geological Survey (USGS) and the Centers for Disease Control and Prevention found that between 11 and 17 organic wastewater-related contaminants (OWCs) remained in wastewater after treatment.

It has been proven that these chemicals have drastic consequences for aquatic life. The September 2007 issue of Environmental Health News summarized a paper by Filby et. al. which studied the effects of one estrogen found in wastewater (17α- ethinylestradiol) on minnows. They found that exposure to wastewater containing estrogen caused “male fish to start producing egg yolk,” effected the blood concentration of hormones, and changed the expression of genes necessary for synthesizing hormones. The minnows also experiences a “decrease [in] the size of testes and alter[ation of] secondary sex characters, including coloration and behavior.”

A 2004 study by Nash et. al. studied the effects of estrogen on zebra fish by exposing them to environmentally relevant concentrations of estrogen. Fish which were exposed for only 40 days did not suffer significant effects, but lifelong exposure caused complete population failure with no fertilization, as the exposure caused the males to lack functional testes and instead have either undifferentiated or inter-sex gonads.

In the media coverage of the AP study, it was frequently mentioned that the effects of drugs at such low concentrations had not been studied in depth in humans, which as far as I can tell is a fair assessment. Still, if one drug can render a fish sterile in 2-5 years (the lifespan of a zebra fish), I cannot imagine what 30 or more years of exposure to a cocktail of drugs could do to people or other wildlife, despite the low concentrations. And, by the way, you can’t escape by drinking bottled water. Most bottling companies filter their water using the same technology as the wastewater plants, and that “pure” spring they draw from is likely already contaminated.

Now I try to keep my blog postings as hopeful as possible, but unfortunately as of yet there is no cost-effective or practical solution. The only successful methods of removing these compounds during wastewater treatment, such as reverse-osmosis, are prohibitively expensive to be performed on all the wastewater generated in the nation. Furthermore, our still rapidly growing world population depends greatly on pharmaceutical birth control, which is more effective than other methods. In order to develop a solution, more research is necessary into improved wastewater treatment technology, and into better drugs that are more efficiently metabolized by the body or have fewer consequences outside it. And of course, little difference though it will make, I know I am going to be thinking a lot more carefully about whether or not I actually need that 4 pm Tylenol.

Another interesting study on the effects of chemicals on frogs can be found here.

And a side note: The antibiotics that end up in our wastewater (whether the penicillin you took for your last infection or the Clorox you used to whiten your towels) contribute to the evolution of drug-resistant strains of bacteria and viruses. While somewhat unlikely, it is possible that our over-zealous need to be “clean” could create a resistant and deadly strain of germ.