Statistical Distribution Features and Evaluation of Ecological Risk in Superficial Sediments of Hulun Lake

摘要

The paper discusses concentrations, statistical distributions and ecological risks of seven heavy metals insuperficial sediments of Hulun Lake. The highest values for heavy metal concentrations in sediments beforethe modern industrialization of the world and grade I criteria of the National Standard for Soil EnvironmentalQuality were used to analyse the accumulation and potential ecological risk (PER) coefficients of heavymetals. The PER index for each sample location is also discussed. The PER index was evaluated using themethod of Lars Hakanson to evaluate ecological risk. The distribution of content of heavy metal does notreveal regional distributive characteristics; the space distribution differential is small. However, three metals(i.e., Zn, Cr, Cu) exhibit the same trend. These heavy metals are highly concentrated in the northeast andsouthwest parts of Hulun Lake than at the entrance of the Xinkai, Wuerxun, and Kelulun rivers. Using thehighest values for heavy metal concentrations in sediments before the modern industrialization of the worldas reference, these heavy metals have an accumulation order of Pb > Zn > Cd > Cu> As > Cr > Hg andpollution level order of Cd > As > Pb > Cu > Hg > Cr > Zn. However, most of these heavy metals are in lowrisk states. Using the grade I criteria of the National Standard for Soil Environmental Quality work as reference,these heavy metals have an accumulation order of Cd > Zn > Cu > As > Pb > Cr > Hg and pollution levelorder of Cd > As > Hg > Cu > Pb > Cr > Zn. Cd is the potential impact element for the ecological environmentin Hulun Lake.