铅稳定同位素在土壤污染物来源识别中的应用

Application of Pb Stable Isotope in Source Identification of Soil Pollutants

稳定同位素是追踪土壤重金属来源的重要手段.根据地统计学研究结果,在某重金属污染场地采集了11个表层土壤样品,它们的Pb浓度呈梯度分布,最大值超过2 000μg.g-1.对土壤样品中4种Pb稳定同位素的含量进行了分析,以了解研究区土壤Pb的主要来源.结果表明,土壤样品206Pb/207Pb、208Pb/204Pb和206Pb/204Pb与Pb浓度的倒数,206Pb/204Pb与208Pb/204Pb都呈显著的线性正相关关系,这些关系符合二元混合模型,由此可以推断土壤铅主要源于人为排放和土壤母质.

Stable isotopes are key importance for tracing the source of heavy metals in soils. 11 surface soil samples were collected in a contaminated site according to geostatistical results, which had a series of concentrations from almost background value of Pb to more than 2 000 μg·g^-1 , Pb stable isotope composition of the soil samples was analyzed to imply the sources. The results showed that ^206 pb/^207 Pb, ^208Pb/^204Pb and ^206 pb/^204 Pb of soil samples were all remarkably correlated linearly with reciprocals of Pb concentration, and ^206 pb/^204Pb had a significant positive linear correlation with ^208 pb/^204 Pb, which was consistent with binary mixing model. It can be inferred that soil Pb mainly came from two sources, an anthropogenic source and soil parent material.