BIOACCUMULATION OF METALS IN DIFFERENT ORGANS OF MANILA CLAM RUDITAPES PHILIPPINARUM: LABORATORY AND TRANSPLANTATION EXPERIMENTS

Abstract

To predict the negative repercussions on benthic organisms caused by discharge of heavily polluted sediment after the operation of tidal power plant (TPP) in Lake Shihwa of Korea, the manila clam Ruditapes philippinarum was transplanted into three different sites where represent heavily metal contaminated site, moderately contaminated site, and reference site, respectively. R. philippinarum collected in outer region of the Lake Shihwa were reared for 56 days (8 weeks) in specially manufactured cages at the bottom of three different sites in Lake Shihwa. Then, the accumulations of heavy metals in their specific tissues were analyzed in every 2 weeks. In heavy metal analysis, 8 different elements (Cr, Co, Ni, Cu, Zn, As, Cd, and Pb) were analyzed in 7 different organs (gill, foot, siphon, adduct muscle, digestive gland, mantle, and residual body). The net accumulation rate and their absolute concentrations of heavy metals in each clam were higher in contaminated site than those of reference site. Furthermore, the net accumulation rates of heavy metals in each clam also had great values in polluted site. In dissected sample, the net accumulation and relatively increasing rate of heavy metal were different according to the elements and organs. For example, the highest concentration of Cd was observed in gills, but the relatively increasing concentration was great in digestive gland. For comparing with in-situ test, we meo three different sites where represent heavily metal contaminated site, moderately contaminated site, and reference site, respectively. R. philippinarum collected in outer region of the Lake Shihwa were reared for 56 days (8 weeks) in specially manufactured cages at the bottom of three different sites in Lake Shihwa. Then, the accumulations of heavy metals in their specific tissues were analyzed in every 2 weeks. In heavy metal analysis, 8 different elements (Cr, Co, Ni, Cu, Zn, As, Cd, and Pb) were analyzed in 7 different organs (gill, foot, siphon, adduct muscle, digestive gland, mantle, and residual body). The net accumulation rate and their absolute concentrations of heavy metals in each clam were higher in contaminated site than those of reference site. Furthermore, the net accumulation rates of heavy metals in each clam also had great values in polluted site. In dissected sample, the net accumulation and relatively increasing rate of heavy metal were different according to the elements and organs. For example, the highest concentration of Cd was observed in gills, but the relatively increasing concentration was great in digestive gland. For comparing with in-situ test, we me