During their production, use, and disposal, pharmaceutical ingredients in prescription and over-the-counter drugs are released into the environment, especially in surface waters. Results from a recent study published in Environmental Toxicology and Chemistry indicate that pharmaceutical pollution is a global problem that is likely negatively affecting the health of the world's rivers.
source https://www.lifetechnology.com/blogs/life-technology-science-news/how-is-pharmaceutical-pollution-affecting-the-worlds-rivers