受污染疏浚底泥用作植物培植土的环境影响分析

资源化利用是疏浚底泥管理方案的基本选择之一。笔者使用上海市受污染河道疏浚底泥为研究对象,通过实验室模拟的方法,分析和评价了受污染疏浚底泥作为城市园林绿化培植土利用过程中对地下水、地表水和土壤可能造成的环境影响。结果表明,中度受污染底泥具有作为绿化用土的基本理化性状,其不利的环境影响主要表现为硝酸盐对地下水的影响及重金属Cd,Hg对地表径流和地下水的影响。其中,硝酸盐的影响只在底泥应用后的第1个植物生长季中出现;重金属污染影响与底泥重金属总含量和可交换态比例有关。控制底泥单位面积的应用量,是控制其不利环境影响的可靠途径。 

Environmental Impacts of Urban Contaminated Dredged Sludge as Vegetative Soil

Beneficial use is one of promising management alternatives for dredged materials.The contaminated dredged material from urban rivers in Shanghai was experimentally researched upon the environmental impacts when beneficially used as vegetative soil.The results show that middle-contaminated dredged material has the basic physical-chemical characteristics of the materials that can be used as vegetative soil.The inverse influences focus on the impact of nitrate on the groundwater and that of heavy metals,e.g.Cd,Hg,on the run-off and groundwater.The impact on nitrate only behaves at the first vegetative production season,while the impact of heavy metals relates to the ratio of the total volume to the transferable proportion.To restrict the applied volume of the contaminated dredged material per unit area and to choose the appropriate species of vegetable are reliable methods to control the inverse environmental influence.