上海世博会规划区不同土地利用方式下附属绿地的重金属分布

上海世博会规划区是工厂和居民区混杂的典型老城区.对其主要土地利用方式下附属绿地土壤的重金属进行调查分析.结果表明:部分样点的Ni、Cr、Cu、Zn、Pb和Cd含量超标,Hg和As的含量均没有超标;大部分绿地土壤没有出现重金属的污染,其中清洁安全和尚清洁占了69.83%和6.94%,轻度污染、中度污染和重度污染的分别占了12.87%、2.56%和7.81%;周边利用类型不同的附属绿地土壤重金属含量差别很大,居民办公区的绿地土壤没有出现重金属污染,试剂溶剂类工厂局部有重金属污染,重金属污染主要集中在造船厂、机械厂、钢铁厂等重型工厂的附属绿地;利用类型不同绿地土壤重金属的相关性也不同,重金属的相关性基本与产生污染的土地利用类型一致;污染源的距离以及对污染源保护不当是导致绿地土壤重金属污染的主要因素,注意对污染源的集中堆置或采取隔离措施,能有效减少重金属对绿地的污染.

Heavy metals distribution in green-belt soils under different land use patterns in planning site of 2010 Shanghai World Exposition

The planning site of 2010 Shanghai World Exposition was a typical old urban district speckled with factories and residential areas.The study on the heavy metals distribution in green-belt soils under different land use patterns in the district showed that the soil Ni,Cr,Cu,Zn,Pb and Cd contents in parts of the district exceeded the National second-level standard,but the Hg and As contents were not.69.83% of the green-belt soils were clean,6.94% were relatively clean,12.87% were slightly polluted,2.56% had a medium degree of pollution,and 7.81% were severely polluted.The soil heavy metals content varied significantly with land use patterns.Residential or business area had no soil heavy metals pollution,but the soils near chemical-reagent factories were partly polluted by heavy metals.Soil heavy metals pollution was mainly occurred in the green belts of ship-building,mechanical,and iron-steel factories.Correlations among soil heavy metals also varied with land use patterns,which was in accordance with the pollution produced from different land use patterns.The distance from pollutant sources and the improper management of wastes were the main factors resulting in the green-belt soil's heavy metals pollution.To reduce the probability of the pollution,wastes and pollutant sources should be well managed to keep them away from the green-belts.