化工区土壤中多环芳烃的污染特征及其来源分析

Characteristics and Sources of Polycyclic Aromatic Hydrocarbons in Surface Soil from Chemical Industrial Areas

系统采集了天津滨海新区3个化工区28个表层土壤样品,利用GC/MS分析了16种US EPA优控多环芳烃(PAHs)的含量和组分特征,运用环数比值法和主成分因子载荷法揭示了其污染来源.结果表明,化工区土壤中PAHs最高含量达5991.7ng.g-1(塘沽化工区),平均含量1185.0 ng.g-1,与国内外相关研究比较,处于中高等污染水平,工业污染排放已明显影响到周边环境中PAHs的残留,且塘沽化工区>汉沽化工区>大港采油区;塘沽和汉沽2个化工区土壤中毒性较高的4环和5环PAHs均高于其他环数PAHs,大港采油区3环所占比例明显占主导;土壤有机碳(TOC)和PAHs之间存在显著相关关系(n=28,R2=0.847,p<0.01),TOC是影响研究区域PAHs在土壤中分配的一个重要因素;煤燃烧的排放是化工区土壤中PAHs污染的主要来源,石油类挥发或泄漏对大港采油区影响显著.

Concentrations and composition of 16 polycyclic aromatic hydrocarbons （PAHs） listed for prior control by US EPA were detected by analyzing 28 surface soil samples from the chemical industrial areas of Tianjin Binhai New Area with a gas chromatography equipped with mass spectrometry （GC/MS）. Relative concentrations of PAH compounds with different benzene rings and principal component analysis were used to identify the possible sources of soil PAHs. The maximum PAH concentration in all the samples was 5 991.7 ng·g^-1 ,with a mean values of 1 185.0 ng· g^-1. The concentrations of four and five rings PAH components were higher than that of the other PAH components in Tanggu and Hangu chemical industrial areas, and three rings PAH components were major PAHs in Dagang petroleum industrial area. There is significant positive correlation （ n = 28, R^2 =0. 847, p 〈 0. 01 ） between PAH concentrations and total organic carbon （TOC） contents in the soil samples. Coal combustion was the dominant source of PAHs in chemical industrial areas, while petroleum volatilization and leakage were main contributors of PAHs in Dagang petroleum industrial area.