遵义市中心城区河道底泥污染评价及底泥清淤方案

为确保湘江河干流和支流水质全面好转,检测和评价遵义市中心城区湘江6条支流及干流上5个水电站底泥重金属和营养盐指标,采用潜在生态风险指数法和综合污染指数法分别评估底泥中重金属和营养盐污染情况。结果表明,所有底泥采样点重金属单项及综合潜在生态风险指数均为低风险,不存在重金属污染;部分河道底泥存在营养盐重度污染。综合考虑河道重金属和营养盐污染状况及河道本底状况,确定底泥清淤深度,共清淤33.8×10~4 m~3。河道采用干式清淤,水电站底泥采用环保清淤船清淤,板框压滤脱水后将秸秆按一定比例混合形成营养土进行资源利用。

Assessment of Status in Sediments and Sediment Dredging Scheme in Central Urban Area of Zunyi City

In order to ensure the overall improvement of water quality in the main stream and tributaries of the Xiangjiang River, this paper tests and evaluates the heavy metals and nutrients in the sediments of the six tributaries and the five hydropower stations in the Xiangjiang River. The potential ecological risk index method and the comprehensive pollution index method were used to evaluate the heavy metal and nutrient salt pollution in the sediment. The results show that all the sediment samples and the comprehensive potential ecological risk index were low risk, and there was no heavy metal pollution. Some river sediments were heavily polluted by the nutrients. Considering the heavy metal and nutrient salt pollution status of the river and the background of the river channel, the sediment dredging depth was determined and a total of 338 000 m3 was dredged. The river channel adopted dry dredging, and the sediment of the hydropower station was dredged by an environmentally-friendly dredging vessel. After the frame was crushed by dewatering, the straw was mixed with a certain proportion to form nutrient soil for resource utilization.