Distribution of mercury and other trace metals in the cockle Cerastoderma glaucum from the Mediterranean Lagoon Etang de Thau

The concentrations of Ag, Cd, Co, Cr, Cu, Ni, Pb, Zn, Mn, and Fe in the sof t tissue of the cockle Cerastoderma glaucum from six sites along the Medite rranean Lagoon Etang de Thau were determined by AAS; Hg was determined by t he cold-vapor technique. Significant spatial variations in metal concentrat ions within the lagoon were recorded. Elevated levels of tissue Pb, Cr, and Hg in the Etang des Eaux Blanches, an area adjacent to the harbor and high ly industrialized region, are likely of anthropogenic origin. Seasonally de pendent variations in the tissue concentrations of trace elements at Crique de l'Angle were observed. The highest levels of Cr and Pb in the tissue we re identified in March 1992, of Hg, Co, and Fe in period August 1990-Januar y 1991, of Mn in August 1992, and Ag in January 1991. The gills contained t he maximum amounts of Co and Ni, the mantle the most Fe and Hg, and the dig estive gland (hepatopancreas) had most Cu.