Abstract: The content and the space distribution of mercury in Anodonta, a representative freshwater shellfish from the main estuary wetlands in Chaohu Lake, were investigated in this study. The results showed that the sediments from the estuary wetlands had been affected by mercury pollution. Especially the pollution in estuary wetlands of Shiwuli River and Nanfei River was most serious. The accumulation of mercury and methyl mercury in Anodonta was obvious and the contents of them were significantly correlated with the contents in sediments. The freshwater shellfish Anodonta was used as an indicator for monitoring the mercury pollution in the estuary wetland. The accumulation of mercury in various tissues had obvious selectivity (mantle＞guts＞gill and muscle). The shellfish evaluation results showed that the contents of mercury and methyl mercury in Anodonta were lower than the limited standards and had a lower risk for eating. Anodonta in estuary wetlands should be divided into the conservation areas for ecological protection and resource utilization.

Key words: estuary wetland, Anodonta, mercury, methyl mercury, bioaccumulation