天津市土壤多环芳烃污染特征、源解析和生态风险评价

Characteristics,sources apportionment and ecological risks assessment of polycyclic aromatic hydrocarbons in soils of Tianjin,China

采用气相色谱-质谱联机方法(GC-MS)分析了天津市不同功能区10个采样点表层土壤样品中16种多环芳烃(PAHs)的浓度,并对其污染特征、来源和生态风险进行了分析.结果表明:天津市土壤中16种多环芳烃的总浓度(∑PAHs)范围为142—1.49×103ng·g-1,平均浓度765 ng·g-1,Bap浓度范围7.06—118 ng·g-1,平均值37.6 ng·g-1.∑PAHs浓度均值呈工业区>近郊区>城区>远郊区趋势.采用PAHs成分谱、污染物的特征比值和主成分分析的污染来源解析结果表明:工业区PAHs主要来源于焦化、煤和天然气的燃烧,以及机动车的污染排放;城区和郊区土壤中PAHs除来自于煤和焦炭的燃烧外,机动车污染是一个非常重要的污染源.根据荷兰土壤质量标准,所有采样点均有PAHs单体超标,其中西青、津南、北辰、汉沽、塘沽和大港采样点超过荷兰土壤标准规定的10种多环芳烃的苯并(a)芘(Bap)毒性当量浓度(TEQ Bap10)限值33 ng·g-1,说明天津近郊区和工业区土壤已受到PAHs的污染,存在潜在的生态风险.

The concentrations of 16 polycyclic aromatic hydrocarbons （PAHs） in 10 surface soil samples collected from various functional zones in Tianjin were analyzed by GC-MS （Gas Chromatography-Mass Spectrometry）. The characteristics, sources of PAHs and ecological risks of the soils were assessment. Results showed that the total concentrations of 16 PAHs （ ∑PAHs）were 142-1.49 × 10^3 ng, g-1 with a mean of 765 ng. g-1, and the concentrations of Benzo （a） pyrene （Bap） were 7.06-118 ng. g- 1 with a mean of 37.6 ng. g- 1, The total concentrations of 16 PAHs decreased in the order of industrial areas 〉 suburban areas 〉 urban areas 〉 outer suburban areas. Source apportionment was studied by PAHs source profile, diagnostic rate and principal component analysis （PCA） methods, The results showed that the PAHs of industrial areas was mainly from combustion of coal, coke and gas, as well as the motor vehicle emission, Except from coal and coke burning, motor vehicle pollution is an important source for PAHs pollution in both urban and suburban areas. According to the Dutch soil quality standards, the concentrations of some monomer PAHs exceeded the standard in all the PAHs （TEQBap10） exceeded the Dutch sampling points. The Bap toxicity equivalent quantity for 10 soil standard limit of 33 ng,g-1 in Xiqing, Jinnan, Beichen,Hangu, Tanggu and Dagang. The soils collected from Tianjin suburbs and industrial areas have a potential ecological risk,which have been polluted by PAHs.