Fate and toxicity of pharmaceuticals in water environment: An insight on their occurrence in South Asia

Pharmaceutically active compounds are newly recognized micropollutants which are ubiquitous in aquatic environment mainly due to direct discharge of treated and untreated wastewater from wastewater treatment plants. These contaminants have attracted mounted attention due to their toxic effects on aquatic life. They disrupt biological processes in non-target lower organisms upon exposure. Biodegradation, photo-degradation, and sorption are key processes which determine their fate in the environment. A variety of conventional and advanced treatment processes had been extensively investigated for the removal of pharmaceuticals from wastewater. However, due to structural complexity and varying operating parameters, complete removal seems ideal. Generally, due to high energy requirement of advanced treatment technology, it is considered cost ineffective. Transport of pharmaceutical compounds occurs via aquatic channels whereas sediments and aquatic colloids play a significant role as sinks for these contaminants. The current review provides a critical understanding of fate and toxicity of pharmaceutical compounds and highlights their vulnerability and occurrence in South Asia. Antibiotics, analgesics, and psychiatric drugs were found predominantly in the water environment of South Asian regions. Despite significant advances in understanding pharmaceuticals fate, toxicity, and associated risks since the 1990s, still substantial data gaps in terms of monitoring, human health risks, and legislation exist which presses the need to develop a more in-depth and interdisciplinary understanding of the subject.