乌鲁木齐市周边地区土壤中多环芳烃的含量及来源

在乌鲁木齐市周边,从乌拉泊到水西沟按不同距离与深度进行土壤样品采集,采用索氏提取法与层析净化法进行预处理,高效液相色谱法测定土壤中16种多环芳烃(PAHs)的含量,并对PAHs进行对比分析、污染评价和来源分析的相关研究。结果表明:总PAHs平均浓度为998.23(306.94~3 652.16)ng/g,污染程度差异不大,处中度污染水平但更接近严重污染水平;16种PAHs的最低检测限为0.20~0.80 ng/g;一些采样点的表层土壤中苯并a]芘的含量高于土壤质量控制标准。不同层次土壤PAHs的污染程度有所不同,其顺序为表层中层下层;高分子量(4~6环)PAHs占据了总含量的84.1%,低分子量(2~3环)PAHs占据15.9%,得出在乌鲁木齐市周边土壤中PAHs的重要来源是汽车排放,同时煤燃烧排放的贡献也很大。

Contents and Sources of Polycyclic Aromatic Hydrocarbons in Soils Aroundd Urumqi City

Representative soil samples were collected from surrounding parts of Urumqi, in different distance and different depth from WuLaPo to ShuiXiGou. Soxhlet extraction method and Chromatographic purification method were employed for 16 kinds of PAHs preparation prior to analysis with High Performance Liquid Chromatography (HPLC) method. Also the comparative analysis, pollution assessment and source analysis were carried on. The determination result shows that the concentrations of the total PAHs (T-PAHs) ranged from 306.94ng/g to 3652.16ng/g with the mean value of 998.23ng/g, although the pollution situation belongs to the moderate pollution level but very close to the serious pollution. The minimum detection limits for the 16 PAHs were from 0.20ng/g to 0.80ng/g. Bap concentrations in some sites exceeded the suggested standards. Contamination degree of soil by PAHs is different in different depths, and the order follows as: top layer > middle layer> bottom layer. High molecular weight PAHs accounted for 84.1% and low molecular weight PAHs accounted for 15.9% of the total contents. These suggested that Automobile emission was still the most important source of PAHs in surrounding environment of Urumqi, but coal combustion be ignored.