四川城市生活垃圾重金属污染状况及来源分析

Pollution and source analysis of heavy metals in municipal solid waste in Sichuan

四川省作为西南粮食生产大省,土壤重金属污染问题备受关注,生活垃圾处理处置可能带来的土壤污染风险急需探明。结合四川省五大经济区的发展格局和多样的地形条件,研究了成都、宜宾、南充、达州、西昌、马尔康城市夏冬两季生活垃圾的物理组成、重金属含量及垃圾主要组分受污染状况。结果表明,四川地区生活垃圾中厨余、包装纸、卫生纸、橡塑和灰土是主要组分,共占总量的78.25%-96.92%;四川地区垃圾中Cu（14.23-107.56 mg/kg）、Cd（0.07-0.63 mg/kg）、Zn（53.77-338.30 mg/kg）、Hg（0.01-0.41 mg/kg）和Cr（35.39-179.63 mg/kg）浓度较高,易造成土壤污染。以土壤环境质量农业用地标准为参照计算得出的重金属污染负荷指数表明：仅夏季宜宾生活垃圾处于Ⅰ级中度污染;四川地区夏冬季总体处于无污染水平,且夏季污染负荷指数略高。通过测定垃圾主要组分中重金属含量,发现厨余和灰土是成都夏季垃圾中Cd的主要来源,灰土是四川地区垃圾中Cu、Zn和Cr的主要来源之一,燃煤产生的灰土是西昌冬季垃圾中Hg的主要来源。

As the biggest grain producing province in southwest China,Sichuan has drawn special attention for soil pollution by heavy metals. It is urgent to investigate soil pollution risk brought by municipal solid waste（ MSW） disposal. Considering the development of the five major economic zones and varied terrain conditions of Sichuan,MSW of six cities including Chengdu,Yibin,Nanchong,Dazhou,Xichang and Ma＇erkang were collected in both summer and winter. Its physical components,heavy metal pollution status of the whole waste and its main components were studied. The results showed that kitchen waste,wrapping paper,toilet paper,plastic and dust were the main components in MSW and accounted for 78. 25% —96. 92%. Cu（ 14. 23—107. 56 mg/kg）,Cd（ 0. 07—0. 63 mg/kg）,Zn（ 53. 77—338. 30 mg/kg）,Hg（ 0. 01—0. 41 mg/kg） and Cr（ 35. 39—179. 63 mg/kg） in MSW were relatively high,and might cause soil pollution easily. The pollution loading index（ PLI）,which was calculated based on soil quality standard of agriculture,indicated that only summer waste of Yibin was at the level of moderate pollution and that the waste of Sichuan was in the range of no pollution in both seasons with a higher summer PLI. Through the measurement of target heavy metal contents in the main physical components of MSW samples,it was found that kitchen waste and dust were the main sources of Cd in Chengdu MSW in summer; dust was one of the main sources of Cu,Zn and Cr in Sichuan MSW and dust from coal burning was the main source of Hg in Xichang MSW in winter.