Don Farrall/Getty Images

DCL

Recently, an investigation showed that trace amounts of drugs were found in the water supply of 24 major cities in the United States. The drugs identified included common over-the-counter pain medications such as ibuprofen and acetaminophen, prescribed heart medications, anti-seizure medications, anti-anxiety drugs, and even some sex hormones. Maybe this is why deer won't get out of my way on my drive home -- they're too sedated from the water!

Though concentrations of these drugs in our water are quite small, and we currently do not believe they have impact on human health, there is some evidence that they are affecting the ecosystem. For example, reports suggest that [pharmaceuticals in the water supply can inhibit the growth of algae -- the small microorganisms that create much of the breathable oxygen in the world.

The truth is, we don't exactly know what effects these medications may be having, but being green means thinking about the best way to properly dispose of things such as leftover medications that could adversely affect the environment. With that in mind, here are some tips on how do dispose of medications in a way that limits your impact:

1.Don't flush medications down the toilet.

Most medication should not be tossed down the toilet. Do not flush any pills except those listed below: atazanavir sulfate (Reyataz Capsules) entecavir (Baraclude Tablets) fentanyl (Duragesic Transdermal System) fentanyl buccal tablet (Fentora) fentanyl citrate (Actiq) gatifloxacin (Tequin Tablets) morphine sulfate (Avinza Capsules) methylphenidate (Daytrana Transdermal Patch) Meperidine HCl Tablets oxycodone (OxyContin Tablets) oxycodone and acetaminophen (Percocet) sodium oxybate (Xyrem) stavudine (Zerit for Oral Solution)

2.Make sure unused medications stay out of the wrong hands.

Take unused medications out of their original containers and throw them in regular trash to make sure people don't illegally reuse them. Mixing pills with an undesirable substance such as kitty litter or coffee grounds and placing the combination in a container or sealable bag works.

3.Find out if your pharmacy can help.

See if your community pharmacy has an unused medication disposal program. Many do. And if you live in Maine, San Francisco, or St. Louis, you're in luck. Residents of Maine who are 65 or older may be eligible to participate in a project funded by the EPA that allows residents to mail in unwanted pills for proper disposal. Residents of St. Louis and San Francisco have access to similar projects.

We're only just starting to understand the effect of drugs in the water supply. Hopefully in the next few years a more universal system of disposing of unused drugs will be available, but for now, taking the steps above is a good start.