The distribution characteristics of methyl mercury in Rana chensinensis and water,sediment and soil in gold-mining areas of the upper reaches of the Songhua River,China were studied by field sampling and laboratory testing.The results show that the methyl mercury contents in water,sediment and soil in gold-mining areas are much higher than those in the control site,indicating that gold-mining activities intensify the methyl mercury pollution in the study area.Methyl mercury contents are in a descending order of sediment > soil > water in the environment,and in a descending order of brain > viscera > muscle > skin in Rana chensinensis.There are significant correlation between methyl mercury contents in Rana chensinensis and those in water and sediment.In particular,the methyl mercury content in the skin of Rana chensinensis is positively correlated with those in water and sediment in spring.Therefore,skin is one of main intake pathways for methyl mercury due to its high permeability.
