Assessment of the levels of polycyclic aromatic hydrocarbons and organochlorine contaminants in bottlenose dolphins (Tursiops truncatus) from the Eastern Atlantic Ocean

The concentrations of 18 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs), and 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the blubber and liver of 27 bottlenose dolphins (Tursiops truncatus) stranded along the Canary Islands coasts from 1997 to 2011. DDTs (mean of 60,960 and 445 ng/g lw., respectively) and PCBs (mean of 47,168 and 628 ng/g lw., respectively) were the predominant compounds in both tissues. Among PCBs the highly chlorinated PCB 180, 153 and 138 were the predominant congeners. We found a p,p′-DDE/∑DDTs ratio of 0.87 in blubber and 0.88 in liver, which is indicative of DDT ageing. All the samples showed detectable values of any of the 16 PAH studied. Phenanthrene was the most frequently detected and at the highest concentration. According to our results, concentrations of OCPs, and especially PCBs, are still at toxicologically relevant levels in blubber of bottlenose dolphins of this geographical area.