Assessing pharmaceutical contamination along the Mediterranean and Red Sea coasts of Israel: Ascidians (Chordata, Ascidiacea) as bioindicators

Abstract

Global increase in the use of pharmaceutically-active compounds (PhACs), and their insufficient removal in wastewater treatment plants, have resulted in their continuous release into the marine environment. We investigated the use of the solitary ascidians Herdmania momus, Microcosmus exasperatus, and Styela plicata as bioindicators of three common PhACs in the Israeli coastal waters: Bezafibrate, carbamazepine and diclofenac. Both the Mediterranean and the Red-Sea coasts were found contaminated with PhACs, detected at all 11 sampling sites, with four sites contaminated with all three studied PhACs. Diclofenac was most frequent, present in nine of the 11 sites with concentrations reaching 51.9 ng/g of dry weight sample (dw). Bezafibrate and carbamazepine reached concentrations of 47.8 ng/g dw and 14.3 ng/g dw, respectively. The alarming detection of such high concentrations of PhACs in ascidians along Israel's coasts demonstrates both the extent of PhACs contamination in the region, and the potential of ascidians as bioindicators, and emphasizes the urgent need for additional research into PhAC contamination sources and effects.

Keywords: Bioindicators; Eastern Mediterranean, Gulf of Aqaba; Pharmaceutical residues; Pharmaceutically-active compounds; Tunicates.