Assessment of metal pollution in Onsan Bay, Korea using Asian periwinkle Littorina bre¨icula as a biomonitor

Cadmium Cd., lead Pb., copper Cu. and zinc Zn. concentrations in the marine gastropod, Littorina bre¨icula Philippi, were determined to assess the metal pollution in Onsan Bay, Korea. Samples of L. bre¨icula employed as a biomonitor and seawater were collected from 12 to 20 stations of Onsan Bay in November 1997, respectively. Dissolved metal concentrations in surface seawater were highest at the station near Onsan Non-ferrous Industrial Complex: 1.15 mg ly1 for Cd, 2.49 mg ly1 for Pb, 3.75 mg ly1 for Cu and 23.98 mg ly1 for Zn. These values were 1]2 orders higher than those shown at outer regions of the Bay. Metal concentrations in the soft body of periwinkles were highly variable at different sampling locations: 0.48]27.11 mg gy1 for Cd, 1.41]24.91 mg gy1 for Pb, 57]664 mg gy1 for Cu and 83]246 mg gy1 for Zn. The values from stations near the industrial complex were higher than those expected from relationships between body sizes and metal body burdens in periwinkles collected from the whole Korean coast. Spatial distribution of metal concentrations in the periwinkle and seawater indicated that Onsan industrial complex near the Bay is the input source of these metals. Especially, Cd and Pb concentrations in the periwinkle and seawater were distinctly decreased with distance from the Onsan industrial complex. Non-essential metals such as Cd and Pb in the periwinkle showed a strong correlation with dissolved metal concentrations in seawater. Conversely, essential Cu and Zn in the periwinkle were hardly explained by those in seawater, except at the most contaminated sites.