A preliminary study of environmental impact assessment of tidal power plant in Shihwa Lake, Korea: Heavy metal accumulation in the transplanted Manila clam (Ruditapes philippinarum)

Abstract

Ra, K., Kim, K.T., Bang, J.H., Lee, J.M., Kim, E.S. and Cho, S.R., 2011. A preliminary study of enviromental impact assessment of tidal power plant in Shihwa Lake, Korea: Heavy metal accumulation in the transplanted Manila clam (Ruditapes philippinarum). Journal of Coastal Research, SI 64 (Proceedings of the 11th International Coastal Symposium), 932 - 936. Szczecin, Poland, ISSN 0749-0208 The Manila clam (Ruditapes philippinarum) was transplanted into heavily contaminated sites and in reference site for 56 days to evaluate the accumulation of heavy metals in the soft tissue of clams and to assess the environmental impact caused by discharge of heavily contaminated sediments after the operation of tidal power plant in Shihwa Lake of Korea. A significant accumulation of heavy metals such as Cr, Cu, Zn, Cd and Pb was observed in the clams transplanted at heavily contaminated site. The results of bioaccumulation factor relative to seawater and sediment suggested that the transplanted clams have a great capacity for Cd, Cu and Zn accumulation than other metals and they can accumulate metals in their tissue from seawater rather than sediment. The calculated net accumulation rates for heavy metals were 1.8-8.4 times greater at contaminated sites than at the reference site. The daily metals uptake per clam was 5.6 ng for Cr, 2.4 ng for Co, 26.6 ng for Ni, 96.2 ng for Cu, 202 ng for Zn, 29.6 ng for As, 2.4 ng for Cd and 7.8 ng for Pb, respectively. However, heavy metal concentrations of transplanted clams in this study are all below the Korean regulation and the guideline of USFDA. The resuspension of contaminated sediments in Shihwa Lake by the operation of tidal power plant can induce that heavy metals release to the seawater. Given the bioavailability of metals for the Manila clam and long-term effects, the consumption of contaminated clams can cause the detrimental effects on human health in the residents. The monitoring and assessment of cumulative environmental impacts on the coastal environment and ecosystem around Shihwa Lake should be necessary after the operation of tidal power plant.