Area public safety and environmental leaders say there are several reasons why Douglas County residents should drop off unwanted or old medication Saturday as part of the second National Medication Take-Back Day.

City and county officials say it’s an effort to guard against prescription drug abuse and to keep old medications from entering the water supply and Kansas River if they are flushed down the toilet.

“It’s the fastest growing drug-abuse problem in the country,” said Sgt. Steve Lewis, a Douglas County Sheriff’s spokesman.

Sheriff’s and Lawrence Police Department officers will operate the Lawrence site from 10 a.m. to 2 p.m. Saturday in the one-hour parking lot next to the Douglas County Courthouse, 1100 Mass.

Experts estimate as much as 40 percent of all medication goes unused, and Lewis said residents should guard against leaving old bottles of prescription drugs in cabinets, especially where children can get access to them. Six of the top 10 substances abused by high school seniors are prescription or over-the-counter drugs, according to national statistics.

The Federal Drug Enforcement Administration is coordinating local sites across the country, and the DEA destroys all medication turned in. Last September, about 100 people turned in more than 180 pounds of unwanted medication at a Douglas County event. That was three times the national average among 4,100 drop-off sites across the nation.

The public can drop off tablets and capsules. Liquid products, like cough syrup, need to be securely sealed in the original container. Lewis said participants should remove prescription labels before turning them in.

The drop-off service is free and will be anonymous. Officers cannot accept intravenous solutions, needles or illegal drugs.

Organizers say the drop-off sites are a community effort between pharmacists, law enforcement, substance abuse advocates and others. Kansas University operated a drop-off site on Wescoe Beach on campus Thursday, and students dropped off 36.7 pounds of unused medication, said KU Public Safety Capt. Schuyler Bailey.

Laura Calwell, the Kansas Riverkeeper, said people should not flush drugs down the toilet because the substances are difficult to eliminate from water systems, and that the chemicals can cause problems for animals living in bodies of water.

“There’s a lot of education that needs to happen,” Calwell said. “It’s a relatively new problem.”