Use of zebra mussel (Dreissena polymorpha) to assess trace metal contamination in the largest Italian subalpine lakes

Trace metal (Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn) contamination was evaluated in zebra mussels from the lakes Maggiore, Lugano, Come, Iseo and Garda, wh ich are located in the most highly populated and industrialised area in Ita ly. Zebra mussels from Lake Maggiore contained the highest concentrations ( 3.44, 1.51, 4.97, 0.158, 5.87, 346 mug g(-1) for Cd, Co, Cr, Hg, Pb, Zn, re spectively) of all metals analysed except Cu and Ni. The lowest levels of m ost metals were in animals from Garda and Lugano (0.78 and 0.60 mug g(-1) f or Cd, 2.87 and 2.03 mug g(-1) for Cr, 0.065 and 0.049 mug g(-1) for Hg, 12 .1 and 11.9 mug g(-1) for Ni, 1.96 and 2.46 mug g(-1) for Pb, 158 and 163 m ug g(-1) for Zn). The most contaminated sites and possible local sources of metals were identified for each lake, and the lakes classified into qualit y classes concerning metal pollution. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.