钢铁工业区下风向土壤中多环芳烃污染特征及源解析

摘要

In order to understand how the steel industry pollutes the soil environment,the concentrations of sixteen priority polycyclic aromatic hydrocarbons (PAHs) in 14 topsoil samples in the steel industrial downwind area in Baoshan District of Shanghai,were determined by gas chromatography-mass spectrometry (GC-MS).Meanwhile,the distribution pattern was discussed,and source apportionment of PAHs in surface soil was conducted via isomer ratio and principal component analysis.The results showed that the concentration of Σ 16PAHs in the surface soil of the steel industrial downwind area ranged from 167.0 to 2355.0 μg/kg,and the average proportion of carcinogenic Σ 7PAHs in Σ 16 PAHs was 50.4％.The average concentrations of Y 16PAHs in the soil adjacent to steel industrial area was the highest (1057.7 μg/kg).The sampling points further away from the industrial area had the relative lower Σ 16PAHs (381.4 μg/kg).BS3,BS6 and BS9 were located in the downwind area of the steel industrial sintering proccss emission zone,resulting in the highest Σ 16 PAHs concentration of BS3 (2355.0 μg/kg) and the concentrations of PAHs decreased in sequence.In addition,fluoranthene was the dominant PAHs compound in the surface soil.The highest carcinogenic BaP concentration ranged from 10.0 to 194.0 μ g/kg.Among different types of PAHs,the proportion of 4 rings PAHs is the highest,followed by 5-6 rings,which accounted for 46.3％ and 39.9％ of the total PAHs respectively.The proportion of d rings PAHs increased with the distance of the sampling points.On the contrary,5-6 rings PAHs ratio decreased.Source apportionment indicated that the PAHs in topsoil originated mainly from the combustion of oil and coal and emission of vehicle exhaust.Research showed that the steel industry had a great contribution to soil PAHs in the downwind area and degressions of the total PAHs concentration and multiple-ring PAHs proportion were observed with the increasing distance from the industry.Soil PAHs in the downwind area were mainly sourced from oil and coal combustion and vehicle exhaust emissions.%为了解钢铁工业区对土壤环境的影响以及土壤的污染状况,采集上海典型钢铁工业区下风向的14个表层土壤样品,应用气相色谱-质谱联用仪(GC-MS)检测了样品中16种优控PAHs(多环芳烃)的含量水平,分析了钢铁工业区下风向土壤中PAHs的组成分布特征,并利用比值法和主成分分析法对土壤中的PAHs进行溯源.结果表明,钢铁工业区下风向土壤中Σ16PAHs(16种优控PAHs的含量)范围为167.0 ～2 355.0 μg/kg,Σ7PAHs(7种具有致癌作用的PAHs的含量)在Σ16PAHs中平均比例为50.4％,近距离样区(＜1 km)表层土壤中Σ16PAHs平均值最高,为1 057.7 μg/kg,远距离样区(5～ 10 km)污染相对较轻,平均值为381.4 μg/kg;宝3、宝6和宝9采样点于钢铁工业区烧结工艺的下风向,导致宝3采样点Σ16PAHs最高,为2 355.Oμg/kg,宝3、宝6和宝9采样点土壤中PAHs含量依次降低;表层(0～20 cm)土壤中PAHs单体含量最高的为荧蒽,致癌性最强的苯并[a]芘含量范围为10.O～194.0 μg/kg,环数组成以4环为主,平均比例为46.3％,其次是5～6环,二者平均比例为39.9％,随着距离工业区越远,4环的组成比例越高,5～6环比例降低;比值法和主成分分析法结果显示土壤中PAHs主要来源于石油、煤的燃烧和机动车尾气的排放.研究显示,钢铁工业对多环芳烃贡献较大,下风向土壤中总多环芳烃的含量和高环多环芳烃比例都呈现明显的随距离递减特征,石油、煤的燃烧和机动车尾气的排放是其多环芳烃的最主要来源.