Is your bathroom cabinet full of small orange-brown bottles with leftover medicines from your last bout of the flu or dentist visit?  Especially now, with so much worry about misuse of opioids, people want to get rid of these old pills safely.  Many experts advise flushing them down the toilet to avoid the potential for abuse.  But wastewater treatment plants are not designed to remove many chemicals so those painkillers, antibiotics, anxiety medicines, etc. often end up in the local waterways. Water-dwelling critters are at risk (some scientists believe this may be contributing to infertility in fish, for example).  And of course having other people’s medicine in the drinking water isn’t a great idea.

What can you do?  First, if you get a prescription for more pills than you think you need, ask if it’s really necessary and if fewer would be OK.  (Saves money, too.) If you do have leftovers, bring them to a collection center.  Many pharmacies will accept unused medicine, and some communities have regular medicine collection drives.  If you can’t find a place to take it and you must dispose of it, crush up the pills, mix them with something inedible like kitty litter or used coffee grounds, and put it in the trash.

https://www.americanrivers.org/threats-solutions/clean-water/pharmaceuticals-personal-care/