A Wisconsin study on what happens to unused prescription and over-the-counter drugs finds most are disposed of improperly.

Of the millions of prescriptions and drugs bought over the counter in 2010, only 2 percent went to programs designed to take back unused medication.

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The study was commissioned by the Wisconsin Department of Natural Resources to assess medication collection programs.

"If these unwanted medications are flushed down the toilet, which a lot of people do to get rid of them, it goes through the sewage treatment plant and those aren't designed to remove this material so it ends up in surface waters, lakes streams," said Brad Wolbert, chief of recycling and solid waste for the DNR.

The study notes there's an increasing number of medication take-back programs in Wisconsin.

Superior is at the forefront of that movement. A drop box program was implemented last month.

The box is open daily in the Superior Police Department lobby in the Government Center, 1316 N. 14th St. All household prescription and over-the-counter medication can be dropped off between 8 a.m. and 4:30 p.m. Monday-Friday.

No syringes, thermometers or needles are accepted. Just cross names off prescription bottles and drop them in the green box, similar to the book drop box at the Superior Library.

The program was launched to protect the environment and citizens. Keeping unused or expired pharmaceuticals in the home can put a family at risk for theft, prescription drug abuse and accidental poisoning, according to Superior Police Chief Charles LaGesse.

"It's great to have it right here as a way to keep our waters healthy and clean," said Wendy Grethen, research assistant with the city of Superior's environmental services division. The medicines are stored safely until they can be incinerated, LaGesse said.

The study also noted that medication take-back programs are expensive. The disposal costs for Wisconsin's take back programs are between $8 and $10 per pound. That's more than twice what Canada and France spend.

One difference is those countries have manufacturers and pharmacies take back the unwanted drugs, similar to how the U.S. gets rid of electronic goods, consumers take it back where they got it.

Telegram writer Maria Lockwood contributed to this story .