以焦作电厂为例,研究了燃煤电厂附近农田土壤中多环芳烃(PAHs)的分布特征.采集了焦作电厂附近农田的土壤,用索氏提取法进行样品处理后,采用气相色谱法对样品中16种PAHs进行了分析测试,初步探索了燃煤电厂附近农田土壤中PAHs污染的特征及分布规律.结果表明,在该研究区域内共检测出10种PAHs,总残留量范围为30.6-740.8μg·kg^-1,属轻微污染水平;但具有致癌作用的组分Fla、Chr和Baa含量约占总量的42%,说明该区域农田土壤存在一定的生态风险.通过对PAHs组成成分分析认为,PAHs污染主要来源于燃烧源.PAHs总量及单污染因子随污染源距离的增加呈现抛物线分布趋势,在距电厂1000-1500m达到最大值;土壤剖面中其峰值出现在0~5cm,且随着深度的增加而呈递减趋势PAHs组分中含量相对较高的Fla、Phe和Pyr3种化合物与各组分及总量间显著相关,Pearson相关系数在0.625~0.999(a=0.05);可以认为,Fla、Phe和Pyr是研究区燃煤电厂附近农田土壤中PAHs的特征性化合物类型.
The distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) in the soils around the Jiaozuo Power Plant were studied. The soil samples were Soxhlet extracted and the contents of 16 EPA priority PAHs in the extract were determined using gas chromatography. Ten EPA priority PAHs were detected in the soil samples. The total PAHs residues in the samples of this area ranged from 30.6 to 740.8 μg· kg^-1 , reaching the level of light pollution. The contents of fluoranthene, phenanthrene and pyrene, three species of carcinogenic PAHs, accounted for 42% of the total content of PAHs, suggesting potential ecological risk from the PAHs in this area. Considering the composition of the PAHs, it can be concluded that the dominant source of PAHs in this area was combustion of coal. The maximum concentration of total PAHs and of the single compounds were detected from 1000- 1500 m around the plant, and in the top 0 -5 cm of the soil. The studies indicate that the abundance of fluoranthene, phenanthrene and pyrene ,sere highly correlated with the total PAHs concentrations with correlation coefficients between 0. 625 to 0. 999 ( a = 0.05) , suggesting the abundance of these three compounds might be good indicators for the total abundance of the PAHs in the soil around the power plant.