燃煤电厂土壤中多环芳烃污染特征及其源解析

Pollution characteristics and source analysis of polycyclic aromatic hydrocarbons in soil of coal fired power plant

本研究以美国环境保护署(USEPA)优控的16种多环芳烃(PAHs)为研究对象,对我国西南某地燃煤电厂采集的10个土壤样品,用气相色谱-质谱联机方法(GC-MS)测定样品PAHs含量,分析PAHs含量特征及其变化规律,在此基础上以污染物源解析方法确定燃煤电厂土壤PAHs的来源。研究结果表明:该电厂土壤中16种PAHs均有检出,其含量范围为4 706～12 175μg/kg,均值为7 436μg/kg,与国内外其他工业区相比属于中度偏高污染;电厂土壤中PAHs含量随距离的增加总体上表现出先减小后增大的趋势,在600 m处采样点PAHs含量出现大幅上升,且不同环数的PAHs与∑_(16)PAHs变化趋势具有较好的一致性;不同层土壤的∑_(16)PAHs含量变化特征有一定的差异,但基本表现为先减小后增大再减小的趋势,200 m处采样点的∑_(16)PAHs含量最高。电厂土壤中PAHs主要来自于石油源和煤的燃烧,其中煤燃烧源的贡献率为67.93%,交通源贡献率为21.74%。

In this study,16 kinds of priority PAHs listed by US Environmental Protection Agency(USEPA)were selected as research objects.Ten soil samples collected from a coal fired power plant in southwest of China were analyzed by gas chromatography-mass spectrometry(GC-MS)to determine the contents of PAHs.Based on the analysis of the characteristics of PAHs and its variation,the source of soil PAHs in coal fired power plant was determined by the method of pollutant source analysis.The results showed that 16 PAHs were detected in the soil of the plant,and the contents of 16 PAHs were 4 706~12 175μg/kg.Average content of PAHs were 7 436μg/kg.Compared with other regions in China and abroad,the PAHs in the soil of the power plant are seriously polluted.The content of PAHs in soil showed the trend of decreasing firstly and then increasing with the increase of distance in general.The content of PAHs increased sharply at the sampling point of 600 m,and the variation of PAHs with different ring number andΣ16PAHs was in good agreement.The variations of contents ofΣ16PAHs in different layers of soils were different,but the tendency reduced at first,then increase and then decrease.The content ofΣ16PAHs reached the highest at 200 m of sampling sites.The analytical solutions of the ratio method show that the PAHs in the soil of the power plant mainly came from oil source and coal combustion.The results of principal component analysis show that the contribution of PAHs coal combustion source in the soil of power plant is 67.93%,and the contribution of traffic source is 21.74%.