Shrimps kept in sea water laced with the level of fluoxetine currently found in their natural habitat change their behaviour. Instead of seeking cover from predators under rocks, they swim towards light. So human drugs may trigger behaviour changes which could unbalance the ecosystem.
What happens to all the medication we prescribe? It’s a challenge to find out.
As we know, a lot isn’t ever taken. In one survey, only 18% of people said they completed courses of antibiotics. Unused pharmaceuticals should be returned to a pharmacy. They are then incinerated. In hospital, end of problem. But in the community, probably only 25% of unused prescriptions find their way back to a pharmacist. People usually throw unwanted medication into the household waste or flush it down the toilet.