Occurrence and ecotoxicological assessment of pharmaceuticals: Is there a risk for the Mediterranean aquatic environment?

Due to their pseudo-persistence and their biological activity, pharmaceuticals are emerging contaminants of major concern for the environment. The aim of this review is to provide an updated inventory of the contamination of aquatic environments by 43 drugs representing different classes of pharmaceuticals, such as antibiotics, anti-inflammatory drugs, anti-depressants, sex hormones, lipid regulators and beta-blockers. The data collected is focused on contamination levels reported in marine coastal waters and in waste and river waters flowing into the Mediterranean Sea. The most widely produced/prescribed classes of medicines are compared with the substances most widely searched for in the environment. Ranges of pollution levels according to the type of water body are also presented, to examine the fate in sewage treatment plants and the persistence in the environment of the targeted molecules. Levels of pharmaceuticals ranged from 100 to 10,000 or even 100,000 ng·L-1 in sewage waters, dropping to 1 to 10,000 ng·L-1 in rivers and to not detected to 3000 ng·L-1 in sea water. However, this paper evidences a lack of data for seawater and also for several countries along the southern coast of the Mediterranean Sea. In order to assess the risk for aquatic ecosystems associated with pharmaceuticals, experimental ecotoxicological values obtained using normalized acute and/or chronic bioassays carried out with different trophic levels were collected for each drug. Targeted biological species and associated bioassays are classified on the basis of their sensitivity to each class of compounds. Occurrence and ecotoxicology are then linked by using the Hazard Quotient (HQ) to assess the environmental risk caused by pharmaceuticals in the Mediterranean Basin. Correlations between HQ and frequency of detection of pharmaceuticals highlighted thirteen compounds that are cause for concern in Mediterranean fresh and sea waters, such as 17α-ethinylestradiol, metoprolol, 8 antibiotics and 3 analgesics/anti-inflammatories.