PCBs and DDTs in Stenella coeruleoalba dolphins from the French Mediterranean coastal environment (2007-2009): current state of contamination.

Organochlorinated compounds including PolyChloroBiphenyles, Dichloro-DiphenylTrichloroethan and metabolites are determinated in Stenella coeruleoalba (n = 37) stranded on the french Mediterranean coasts from 2007 till 2009. Studies are carried out on lung, muscle, kidney, liver, and blubber. The sought-after compounds are all detected to variable levels in each tissue and organ. In general, total PCBs are the most abundant, followed by total DDTs. The concentration (in ng g(-1) of lipid weight) in blubber of S. coeruleoalba, varied from 2,052 to 158,992 for PCBs and from 1,120 to 45,779 for DDTs. The ratios DDE/tDDTs are higher than 80% in almost all samples. The overall results of this work, compared to previous studies concerning the Mediterranean Sea, seems to confirm the tendency to a decrease of the contamination by organics compounds for the cetaceans in the Western Mediterranean Sea.

Accumulation and distribution of organochlorines (PCBs and DDTs) in various organs of Stenella coeruleoalba and a Tursiops truncatus from Mediterranean littoral environment (France).

The objective of the present study is to determine the levels of contamination by PCBs, DDT and its metabolites in dolphins failed on the coasts of the Mediterranean sea. Samples are represented by six Stenella coeruleoalba and a Tursiops truncatus collected in 2000 and 2003. The studies are achieved on the blubber, the heart, the liver, the kidney, the muscle and the lung. The concentrations of PCBs and DDT are very high in all tissues and organs analyzed. For the PCBs, the concentrations vary between 43,838 and 110,343 microg/kg lipid basis in the blubber, 601 and 39444 microg/kg dried weight in the liver, 1375 and 34512 microg/kg dried weight in the muscle, 3151 and 17082 microg/kg dried weight in the heart, 674 and 12365 microg/kg dried weight in the kidney and finally between 648 and 4118 microg/kg dried weight in the lung. These values are comparable to those previously obtained in our laboratory and by other authors during the years 1990 on the Mediterranean environment. Significant differences in concentrations are noted in tissues and organs, neither according to the age, nor according to the gender. In all the analyzed samples, the contents in PCBs are higher than those of DDT. The average ratios of pp'-DDE/SigmaDDT are close to 0.6 which shows the metabolization of these compounds along the years. The examination of the profiles of congeners shows that the hexachlorinated molecules are dominating in all tissues and organs which supposes the different animals were especially exposed to Pyralen-type compounds of transformer (Dp6).