杨凌城市生活垃圾中重金属元素的污染特性分析

A Pollution Characteristics of Heavy Metals in Municipal Solid Waste of Yangling City

采用异地取样和理化分析的方法对杨凌城区生活垃圾中重金属元素的含量、浸出毒性进行了测定。通过污染负荷评价得到主要污染元素,并在调查的基础上对重金属来源进行了分析,提出了重金属污染的防治对策。结果表明,垃圾中塑料含量以学生生活区最高,高达41.47%;可腐有机物含量西农学生生活区最高,达到32%～46%,化安生活区最低,只有5.076%;筛下混合物西农学生生活区较低,在20%左右,其他各采样点在37.91%～69.30%。同一采样点的不同重金属元素的含量,表现为Zn的含量最高,变化范围为76.63～704mg·kg-1,其次是Cu和Cr,变化范围分别是7.26～226.7mg·kg-1和13.24～90.21mg·kg-1,As的含量最低,变化范围在0.49～18.52mg·kg-1。生活垃圾因产生主体不同而使污染元素的可浸出态含量差别较大,但不具有浸出毒性危险。杨凌城市生活垃圾中As的污染负荷远远高于Zn和Cu。

The content of heavy metals and leaching toxicity of MSW were measured by sampling on the other spots and physical-chemical analysis. Main pollution metals were determined through pollution load assessment and the source of heavy metals was analyzed by investigation. The results were as follows: The plastic and the organic matter in students living areas were both highest, up to 41.47%and 32%～46%, respectively. Below-sift amalgam in most sampling spots was 37.91%～69.30%except students living areas. The content of Zn was higher than the other heavy metals in every spots, up to 76.63～704 mg·kg-1.The contents of Cu, Cr and As ranged from 7.26 to 226.7 mg·kg-1, from 13.24to 90.21 mg·kg-1 and from 0.49 to 18.52 mg·kg-1. Leaching of pollution metals in MSW from different sources differed greatly, but had no leaching toxicity danger. The pollution load of As far exceeded Zn and Cu. Cu in composting materials probably came from printed material, while Cu in below-screened matter might come from dust. Zn came from battery and dust, Pb came from plastics and As and Pb in below-sift matter came from dust.