I'm not totally sure why that's any better than throwing them into the trash. Are people really digging through garbage just hoping to find opiates?

However, presuming you're not on a septic system, they end up in the river, just like any other form of pollution.

Lots of police departments are taking them no questions asked. The city where I work's police/public affairs building has a big metal box with a one-way lid for unused drugs.