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| Distribution and ecological risk assessment of heavy metals in surface sediments of Yelang Lake |
| Received:September 12, 2016 |
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| KeyWord:sediment;heavy metals;distribution;speciation;risk assessment;Yelang Lake |
| Author Name | Affiliation | E-mail | | XU Meng | College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China | | | LIU Hong-yan | College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China
College of Agriculture, Guizhou University, Guiyang 550025, China | hongyan.l@163.com | | LUO Kai | College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China | | | CUI Jun-li | College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China | | | LIU Yan-ping | College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China | | | LI Jia-fei | College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China | |
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| Abstract: |
| Carbonate rock, which is typical heavy metals geochemical anomaly karst terrain, accounts for 73% of the land area in Guizhou Province. The geochemical background value of Cd is 0.31×10-6, which is 2.5~3.5 times higher than the abundance value. Therefore, the accumulation, release, and environmental risks of heavy metals should be studied in this region. To evaluate pollution levels comprehensively, the concentration and speciation distributions of seven heavy metals(Zn, As, Cd, Cr, Ni, Cu, and Pb) were analyzed in surface sediments from Yelang Lake. The geoaccumulation index(Igeo) and the potential ecological risk index(RI) were used to assess the potential contamination and the environmental risks associated with heavy metals. The results showed that the mean contents of Zn, Pb, Cr, Ni, Cu, As, and Cd in the surface sediments were 141.75, 83.76, 54.97, 38.60, 36.61, 9.47, and 1.50 mg·kg-1, respectively. These contents, excluding As and Cr, were higher than the geochemical background values of supergene sediments in Guizhou Province. Cr, Ni, Cu, and As in the sediments were dominated mainly by the residual fraction, which accounted for 52.56%~80.21%, 30.09%~70.43%, 38.05%~80.77%, and 70.04%~94.89%, respectively. The reducible fractions of Pb and Zn were higher than they were for the other metals, and the percentages of the exchangeable and reducible fractions of Cd were 10.93%~49.15% and 25.58%~62.49%, respectively. The Igeo showed that there were more serious degrees of Pb and Cd contamination in Yelang Lake. The RI showed that Cd is the main ecological risk factor, which was affected by sediment from the fish culture in net pen, and the pollution degree of heavy metals in the surface sediments from Yelang Lake represented light to moderate ecological harm. Therefore, Cd geochemical background levels in karst areas are a high potential environmental risk for aquatic areas. |
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