Occurence of pharmaceuticals in surface water

Abstract

Pharmaceuticals constitute a large group of human and veterinary medicinal organic compounds which have long been used throughout the world. According to their therapeutic activity they are classified in several groups: antibiotics, analgesics/antipyretic, CNS (Central nervous system) drugs, cardiovascular drugs, endocrinology treatments, diagnostic aid-adsorbable organic halogen compounds. Pharmaceuticals are designed to have a physiological effect on humans and animals in trace concentrations. Pharmaceuticals end up in soil, surface waters and eventually in ground water, which can be used as a source of drinking water, after their excretion (in unmetabolized form or as active metabolites) from humans or animals via urine or faeces. The possible fates of pharmaceuticals once they get into the aquatic environment are mainly three: (i) ultimately they are mineralized to carbon dioxide and water, (ii) the compound does not degrade readily because it is lipophilic and is partially retained in the sedimentation sludge and (iii) the compound metabolizes to a more hydrophilic molecule, passes through the wastewater treatment plant and ends up in receiving waters (which are surface waters, mainly rivers). These compounds exhibit the highest persistence in the environment. In recent years, and in particular after the use of the advanced measurement technologies, many pharmaceuticals have been identified worldwide and detected at ng/L levels (trace concentrations) in the aquatic environment, and are considered as an emerging environmental problem due to their continuous input and persistence in the aquatic ecosystem even at low concentrations.