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).

Effects of 12 years' operation of a sewage treatment plant on trace metal occurrence within a Mediterranean commercial sponge (Spongia officinalis, Demospongiae).

The present field study uses Spongia officinalis for assessing trace metals occurrence in time and space within Mediterranean rocky communities. Nine sites were selected in the Marseille area for studying spatial trends in 12 metal concentrations. Long term changes in 8 metal concentrations were assessed at sites that had been sampled before and 12 years after the opening of a treatment plant. Spongia officinalis highly concentrated all the trace metal surveyed excepted Hg and Cd. The overall contamination level registered provided a classification of the study sites which is congruent with that given by other studies on pollutant accumulation in neighbouring sandy-bottoms or benthic assemblages. Among the metals studied, Fe, Pb, Cr are those that best highlighted a pollution gradient. In the present study, only Cd concentration did not vary in space. Except for Ni, all pollutant concentrations clearly decreased between 1984 and 1999. This very impressive decrease in heavy metal concentrations within the Marseille area represents an indisputable evidence of the improvement of the seawater quality resulting from 12 years' operation of the Marseille sewage plant. Moreover, the significant decrease also recorded in the reference population at Port-Cros might reflect an overall improvement in the seawater quality of the NW Mediterranean.