铅同位素解析技术在工业园污染溯源中的应用

Application of lead isotope analysis technique for pollution sources identification in industrial parks

针对土壤中重金属污染溯源及解析不同污染源对土壤中铅的相对贡献率问题,以陕西西部某工业园区为例,采集土壤样品、铅锌冶炼厂矿石混合样、热电厂煤样及焦化厂混合煤样共40个,用ICP-MS测定样品的铅浓度及铅同位素比值(208Pb/204Pb、207Pb/204Pb、206Pb/204Pb)。借助于铅同位素比值散点图来对比分析采样点土壤、背景点土壤和可能的污染源样品的铅同位素特征分布,判定其主要污染来源。用混合多元模型计算不同污染区域各污染源的贡献率,结果表明,土壤中的铅同位素比值落在铅锌矿石、炼焦用煤及热电燃煤及背景点的铅同位素比值之间,说明各端元介质均有可能对工业园区土壤中的铅污染有贡献。在铅同位素比值散点图中土壤铅浓度大于60 mg/kg的采样点的铅同位素比值集中落在热电燃煤与炼焦用煤附近。统计定量解析结果可知,对工业园区土壤铅污染的贡献大小依次为热电厂、焦化厂和铅锌冶炼厂。研究表明,铅同位素指纹解析技术用于定性与定量解析工业园区土壤铅污染效果较为理想。

This study provides lead concentration and lead isotope ratios(208Pb /204 Pb,207Pb /204 Pb,206Pb /204Pb) by ICP-MS approach,collecting and examining 40 soil samples,mixed ores of lead and zinc smelter,coal of thermal power plants and coal coking plants in a western Shaanxi industrial park. The analysis of lead isotope ratio scatter diagrams reveals main sources of lead pollution through isotopic characteristic comparision of sample soil,background soil,possible polluted soil. The solution of a mixed multivariate model shows that lead isotope ratios in soil falls between thermal power plants lead and zinc ores,coal of coking,thermal power and background points,which means that each substance of the samples is likely to contribute to the lead pollution.In lead isotope ratios scatter diagrams,soil of greater than 60 mg / kg fall near coal of thermal power and coal coking plants. The results of quantitative analysis show that the causes of lead pollution are,in bigger to smaller sequence,thermal power plants,coking plants and lead-zinc smelter. We found that finger print lead isotope technique is appropriate to quantitative analysis for soil lead pollution of industrial parks.