调水后受水区水环境的演化及重金属污染评价

本文通过渭河原水和客水的混合稀释实验模拟调水后受水区水环境的演化，价调水后水环境的重金属污染特征、含变化规律及潜在的生态风险。研究结果表明：在pH、矿化度等其他因素和重金属间相互作用下，渭南和咸阳段混合水体中重金属Co、Cr、Mn、Mo、Pb和V的含量基本上随客水混入量的增大而下降，水质呈良性发展；客水汇入后，受混合稀释作用的影响，混合水的重金属内梅罗综合污染指数P综合平均降低幅度达到60%左右，重金属污染程度明显降低；调水后受水区水环境中单个重金属潜在生态风险系数和潜在生态危害指数RI明显降低，重金属Cr、Mn、Pb的潜在生态风险系数平均下降幅度分别达到50%、70%、56%左右，潜在生态危害指数RI的平均下降幅度为57%作用，说明调水的混合稀释作用可以明显降低重金属的潜在生态风险。 The mixture dilution experiment of Weihe River water and incoming water was performed to simulate the water environment evolution in the water receiving area after water transfer and to assess the pollution characteristics of heavy metals in the water environment and the potential ecological risk. The results showed that (1) the contents of Co, Cr, Mn, Mo, Pb, and V in the mixed water of Weihe River of the Weinan and Xianyang sections decrease with the increasing volume of incoming water due to the impacts of the interactions among pH, TDS, and heavy metals, and water quality of the mixed water improves; (2) the comprehensive pollution index of heavy metal (Nemoro P综合) of the mixed water reduces by about 60% in average due to mixture dilution, and the pollution degree of heavy metals decreases significantly; and (3) the potential ecological risk coefficient of single heavy metal and potential ecological risk index RI in the water environment of the water-receiving area after water transfer reduce apparently. The average decline rates of the potential ecological risk coefficients of Cr, Mn, and Pb are 50%, 70%, and 56% respectively, and the average decline rate of the potential ecological hazard index RI is 57%, which indicates that the mixture dilution can decrease the potential ecological risk of heavy metals significantly.