DNA Alterations Triggered by Environmentally Relevant Polymetallic Concentrations in Marine Clams Ruditapes philippinarum and Polychaete Worms Hediste diversicolor

We exposed marine clams (Ruditapes philippinarum) and aquatic worms (Hediste diversicolor) to environmentally relevant concentrations of two metal mixtures each containing three divalent metals [(C-1 in A mu g/L) cadmium (Cd) 1, mercury (Hg) 0.1, and lead (Pb) 4] and [C-2 in A mu g/L) Cd 17, Hg 1.1, and Pb 55]. Animals collected in the Arcachon Bay were exposed for 8 days in microcosms made up of a mixed biotope consisting of a water column and natural marine sediment both taken up from the Arcachon Bay. Bioaccumulation analysis showed a significant increase of Cd, Hg, and Pb in clams, particularly at C-2 concentration in the water column reaching, in soft body, 2.3 +/- A 0.3 A mu g Cd/g, 0.7 +/- A 0.2 A mu g Hg/g, and 45 A mu g Pb/g dry weight (dw). DNA alterations and upregulation of the cox1 mitochondrial gene were also observed in clam gill after exposure to the metal blend. For worms exposed to the C-2 metal blend, DNA alterations and significant increase of Cd and Hg concentrations were observed reaching 0.5 +/- A 0.1 A mu g Cd/g and 2 +/- A 0.6 A mu g Hg/g dw.