Nearly 30 tons of unused drugs — that's about five big elephants' weight in pills — were dropped off at "take back" boxes in Pennsylvania, New Jersey, and Delaware on Saturday, yet another piece in the nation's uphill battle against opioid addiction and overdose. More than a third of the total came from the eight-county Philadelphia region.

The amount of excess medications picked up on National Prescription Drug Take-Back Days has varied from year to year and county to county, with less collected at the last event in October but more the previous April (and less than half when the official take-back day coincided with Pope Francis' visit to Philadelphia in fall 2015).

Patrick J. Trainor, special agent and public information officer for the Drug Enforcement Administration's Philadelphia division, noted that there are now far more drop boxes permanently installed around Pennsylvania, through the state Department of Drug and Alcohol Programs. About 580 boxes are located around the state. The New Jersey Division of Consumer Affairs lists hundreds more.

"People are taking advantage of the permanent boxes," Trainor said, and so the total amount of old medicine vials turned in through the year would be significantly higher than what was reported Wednesday.

Surveys have shown that most people who become addicted to opioids started on pain pills that were legitimately prescribed for them, leftover from an old prescription, or were taken from the medicine chest of a family member or friend. Experts say it is best to get rid of any unused pills — but not by throwing them in the garbage or down the drain, where they can contaminate drinking water.

On Saturday, the DEA collected all the discarded drugs from drop boxes overseen by law enforcement in each county to be burned in an incinerator approved for that purpose by the Environmental Protection Agency, Trainor said.

The agency's Philadelphia division, which covers Pennsylvania and Delaware, collected 37,739.63 pounds of discarded drugs from take-back boxes that had been set up for the day in Pennsylvania, and an additional 5,210.8 pounds from Delaware.

The total included more than 19,680 pounds from the Philadelphia region: Bucks County (9,893 pounds), Chester County (1,280 pounds), Delaware County (410 pounds), Montgomery County (7,204 pounds), and Philadelphia (900 pounds).

The New Jersey division took in 15,929 pounds statewide. That included Burlington County (1,067 pounds), Camden County (2,292 pounds), and Gloucester County (772 pounds).