Persistent organochlorine pollutants and heavy metals in tissues of common bottlenose dolphin (Tursiops truncatus) from the Levantine Basin of the Eastern Mediterranean

DDT's, PCBs and heavy metals (HM) were measured in tissues of common bottlenose dolphins, collected along the Israeli Mediterranean coast during 2004-2006. ΣDDT and PCBs concentrations were highest in the blubber, with a wide concentration range of 0.92-142 and 0.05-7.9 mg kg^-1 wet weight, respectively. Blubber PCBs values were an order of magnitude lower than in tissues of this and other delphinid species in the Western Mediterranea. We found relatively high DDE/ΣDDT percentage (85-96%); a common indicator of DDT degradation, which fitted the general trend of increase in the last 20 years in the Mediterranean Sea, indicating the progressive degradation of the remnant DDT and the absence of new inputs. Concentrations of HM ranged as follows: 0.01-123 mg kg^-1 wet weight for Hg, <0.04-1.3 for Cd, 1-30 for Cu, 0.3-4 for Mn, 19-517 for Fe, 4.3-68 for Zn and 2.4-48 for Ni. These concentrations were similar to those found in specimens collected during previous years in the region, suggesting stability over time in the HM levels of the basin's food-web.