温州河道底泥重金属污染特征和分级评价

Characteristics and Grading Evaluation of Heavy Metals Pollution of River Sediment in Wenzhou

为评估温州重点区域河道底泥的重金属污染状况,进而为受污染河道底泥清淤工作分类制定科学环保的处理处置方案,通过对温州市龙湾区、瓯海区和瑞安市14条河道底泥样品测定Cu、Zn、Cd、Cr、Ni、Pb和Hg等7种重金属元素的全量浓度,并参照《浙江省河湖库塘清淤技术指南(试行)》制定的5级污染物控制指标和限值,通过改进型内梅罗污染指数方法对温州14条河道底泥样品的重金属污染进行了分级评价,评价结果表明,14条河道中,有3条河道底泥未受重金属污染可用于土地改良等;有2条河道底泥受重金属轻微污染可用于园林绿化等;有6条河道底泥受重金属中度污染可用于回填土等;有1条河道底泥受重金属重度污染可用于制砖等;有2条河道底泥受重金属严重污染,通过浸出毒性分析可鉴别为一般固废,其底泥可脱水后进行卫生填埋。

In order to evaluate heavy metal pollution status in river sediments of key areas in Wenzhou, and establish scientific and environmental plans for sediment dredging of polluted river. The contents of heavy metals, including Cu, Zn, Cd, Cr, Ni, Pb and Hg were analyzed in 14 fiver sediment samples of Longwan District, Ouhai district and Ruian city- in Wenzhou. On this basis, the heavy metal pollution status of 14 river sediment samples in Wenzhou were evaluated by the improved Nemerow index method, and reference to control index and limit of 5 levels of pollutants in technical guideline of sediment dredging of rivers, lakes, reservoirs and ponds of Zhejiang province. The evaluation results showed that, among the 14 rivers, sediment in 3 rivers were not polluted by heavy metals and could be used for land improvement, sediment in 2 rivers were slightly polluted by heavy metals and could be used for landscaping, sediment in 6 rivers were moderately polluted by heavy metals and could be used as backfill soil, sediment in 1 fiver was heavy polluted by heavy metal and could be used to make bricks, sediment in 2 rivers were seriously polluted by heavy metals and identified as general solid waste through the extraction toxicity- identification, the river sediment should go to landfill after dewatering.