东川小江流域河漫滩沉积物重金属污染分布特征及生态风险评价

以小江河漫滩沉积物为研究对象，在河流上、中、下游采集42个河漫滩沉积物样品，对其理化性质及Cu、Pb、Mn、Zn、Cr、Cd共6种重金属含量进行测试，并利用地累积指数法和潜在生态风险法进行污染风险评价。结果表明：小江河漫滩沉积物中重金属Cu、Pb、Mn、Zn、Cr、Cd元素浓度分别为218.68、93.48、1347.97、414.39、71.04、2.47 mg/kg，除了Cr，其他元素含量均超过昆明土壤重金属环境背景值（Cu：69 mg/kg、Pb：41 mg/kg、Mn：606 mg/kg、Zn：90 mg/kg、 Cd：0.27 mg/kg）。Cd、Zn元素含量均值分别是环境背景值的9.17、4.60倍，分布存在空间差异性，主要污染源自人类活动；单项重金属潜在生态风险系数均值由大到小依次为Cd（274.98）、Cu（14.67）、Zn（4.60）、Mn（2.22）、Pb（1.79）、Cr（1.44），潜在生态风险指数RI的均值为300达到强生态风险程度；小江河漫滩沉积物中的重金属Cu、Zn处于富集状态，Cd处于高富集状态。因此，小江流域已出现重金属污染，且存在潜在生态风险，需要采取适当的监测和相应的治理措施。

Distribution Characteristics and Ecological Risk Assessment of Heavy Metal Pollution in Floodplain Sediments of Xiaojiang River Basin in Dongchuan

Taking the Xiaojiang River floodplain sediments as the research object, 42 samples of floodplain sediments were collected from the upper, middle and lower reaches of the river, and their physical and chemical properties and the contents of 6 heavy metals including Cu, Pb, Mn, Zn, Cr, and Cd were tested. The pollution risk was evaluated by geo-accumulation index method and potential ecological risk method. The results showed that the concentrations of heavy metals Cu, Pb, Mn, Zn, Cr and Cd in the sediments of the Xiaojiang River floodplain were 218.68 mg/kg, 93.48 mg/kg, 1347.97 mg/kg, 414.39 mg/kg, 71.04 mg/kg and 2.47 mg/kg, respectively, except for Cr, the contents of other elements exceeded the environmental background values of heavy metals in Kunming soil(Cu: 69 mg/kg, Pb: 41 mg/kg, Mn: 606 mg/kg, Zn: 90 mg/kg, Cd: 0.27 mg/kg). The contents of other elements were all higher than the environmental background value of heavy metals in Kunming soil. The average contents of Cd and Zn were 9.17 and 4.60 times of the environmental background value, respectively. There were spatial differences in distribution, and the main sources of pollution were human activities; the mean value of potential ecological risk coefficient of single heavy metal from large to small was Cd(274.98), Cu(14.67), Zn(4.60), Mn(2.22), Pb(1.79), Cr(1.44), and the mean value of potential ecological risk index RI was 300 to reach the level of strong ecological risk; heavy metals Cu and Zn in sediments of Xiaojiang River floodplain are enriched, while Cd is highly enriched. In summary, heavy metal pollution has occurred in Xiaojiang River basin, and there are potential ecological risks. Appropriate monitoring and corresponding control measures are needed.