Total (T-Hg) and organic (O-Hg) mercury concentrations and tissue distribution were examined in 20 species of cephalopods (n=278) from the north eastern Atlantic waters, i.e. from the Bay of Biscay to the Faroe Islands. Concentrations of T-Hg in whole cephalopods showed elevated variations among species, i.e. from 40 to 3560ng g(-1) dwt, but a low variability within each species (mean CV%=39%). With the exception of oceanic squids, the digestive gland globally displayed higher T-Hg concentrations than the remaining tissues. In contrast, O-Hg concentrations determined in selected species were generally higher in the remaining tissues. Despite higher T-Hg concentrations, the digestive gland weakly contributed to the total body burden of both T-Hg and O-Hg (<25% and <15%, respectively). In fact, from 75% to 95% of the T-Hg and O-Hg were contained in the muscular remaining tissues. Therefore, O-Hg may have a strong affinity to proteins in cephalopods. Sex and size only significantly influenced the bioaccumulation of Hg for the Loliginidae family. T-Hg and O-Hg concentrations were also influenced by geographical origin: Celtic Sea>Bay of Biscay>Faroe Islands, corresponding to the seawater Hg concentrations in these areas. In the Faroe Islands and the Celtic Sea, benthic cephalopods contained significant higher Hg concentrations compared to pelagic ones. This suggests that diet is not the main pathway of Hg uptake in cephalopods as pelagic species were expected to be more exposed to O-Hg through fish consumption than benthic ones.
High PCB levels were recorded in porpoises and common dolphins from European coasts.
AbstractConcentrations of polychlorinated biphenyls (PCBs) in blubber of female common dolphins and harbour porpoises from the Atlantic coast of Europe were frequently above the threshold at which effects on reproduction could be expected, in 40% and 47% of cases respectively. This rose to 74% for porpoises from the southern North Sea. PCB concentrations were also high in southern North Sea fish. The average pregnancy rate recorded in porpoises (42%) in the study area was lower than in the western Atlantic but that in common dolphins (25%) was similar to that of the western Atlantic population. Porpoises that died from disease or parasitic infection had higher concentrations of persistent organic pollutants (POPs) than animals dying from other causes. Few of the common dolphins sampled had died from disease or parasitic infection. POP profiles in common dolphin blubber were related to individual feeding history while those in porpoises were more strongly related to condition.
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