伊通河(城区段)沉积物重金属形态分布特征及风险评价

Speciation Distribution and Risk Assessment of Heavy Metals in Sediments from the Yitong River City Area

通过对伊通河(长春城区段)7个沉积短岩芯中Cd、Cr、Cu、Ni、Pb和Zn等重金属元素含量与赋存形态的分析,研究了重金属污染特征和潜在生态风险.沉积物中Cd、Cr、Cu、Ni、Pb和Zn含量范围分别为0.10~1.18、23.57~66.35、11.27~43.95、10.78~29.82、15.02~60.81和54.27~175.83 mg·kg^-1.Cd弱酸可溶态的质量分数为42.1%~51.28%;Cr、Ni和Zn以残渣态为主,质量分数分别为63.54%~79.91%、35.16%~53.75%和27.55%~57.55%.沉积物垂向污染程度和生态风险评价结果显示,研究区域受到Cd、Cu、Pb及Zn污染,Cd的生态风险最高,Zn和Cu次之,各岩芯中每组元素具有相似的垂向变化规律,其中4~8 cm深度生态风险相对较高.污染来源解析结果显示,伊通河(城区段)沉积物中Cd、Zn和Pb主要来源于工业污染和城市污水排放,Cu可能受自然过程和人类活动的双重影响,Cr、Ni可能较多地来源于自然过程.

The total content and chemical speciation of Cd,Cr,Cu,Ni,Pb,and Zn in seven short cores sampled from the Yitong River from Changchun City were analyzed to assess the pollution levels and potential ecological risks of heavy metals in the sediments.The results demonstrated that the total contents of Cd,Cr,Cu,Ni,Pb,and Zn in sediments were 0.10-1.18,23.57-66.35,11.27-43.95,10.78-29.82,15.02-60.81,and 54.27-175.83 mg·kg^-1,respectively.The acid-soluble fraction of Cd varied from 42.1%to 51.28%,whereas Cr,Ni,and Zn were mainly found in the residual fraction;their mass fractions were 63.54%-79.91%,35.16%-53.75%,and 27.55%-57.55%,respectively.The vertical results of pollution degree and ecological risk assessment indicated that the studied sediment was polluted by Cd,Cu,Pb,and Zn,and the ecological risk of Cd was the highest,followed by Zn and Cu.Each group of metals in each core showed a similar vertical variation,and the ecological risk of metals in sediment of 4-8 cm depth was relatively high.Cd,Zn,and Pb in the sediments of Yitong River were mainly from industrial pollution and municipal sewage discharge,and Cu could be attributed to both natural processes and human activities,whereas Cr and Ni may be attributed to natural processes.