PERSISTENT CONTAMINANTS IN DOLPHINS - AN INDICATION OF CHEMICAL POLLUTION IN THE MEDITERRANEAN-SEA

Concentrations of metals (mercury and methylmercury, selenium. cadmium , lead), chlorinated pesticides and polychlorinated byphenyls (PCB) ha ve been determined in tissues and organs of Stenella coeruleoalba dolp hins beached along the Adriatic and Ionian coasts of Apulia (Southern Italy). The results obtained confirm that in Mediterranean dolphins th e accumulation of contaminants is higher than in similar species livin g in the Atlantic. Therefore cetaceans can be considered ''organisms i ndicating pollution''. Accumulation is influenced by factors such as d iet, age and sex, Reproduction plays a fundamental role in the elimina tion of toxic compounds in females. Correlation between contamination and death has not been found; however it is clear that pollutants at s ub-lethal doses have neuro-toxic effects, increase stress and alter im mune defences, leaving the organism at a greater risk from disease.