From Environmental Health Perspectives:

The state of Maine experimented with drugs last year. The state had already tested several methods
for collecting unused pharmaceuticals, with varying degrees of success. After tracking surprisingly high concentrations of pharmaceuticals in landfill leachate —raising the potential for eventual ground and surface water contamination—the state decided to pursue a new tool to keep drugs out of the waste stream. Maine wanted to establish statewide collection programs, mandated 
by legislation and paid for by manufacturers, that would intercept unwanted pharmaceutical products before they got to the trash.

Although the state legislation bogged down earlier this year, other states have introduced bills similar to Maine’s, with some success. Meanwhile, Europe and Canada have had systems for pharmaceutical take-back programs in place for a decade or so. At the same time, an increasing number of reports from across the world have tracked active pharmaceutical ingredients (APIs) in surface waters and even tap water, leading environmental scientists and water utilities to look for ways to limit the amount of drugs entering the environment. Read more.