深圳表层土壤中多环芳烃的污染特征及来源

Distribution and source of polycyclic aromatic hydrocarbons (PAHs) in topsoil of Shenzhen

2007年1月采集深圳市36个土壤．采用气相色谱-质谱仪对其中的16种优先控制的多环芳烃（PAHs）进行分析。结果表明：16种PAHs的含量范围在67．7-7137．0ng·g^-1之间，平均值为664．7ng·g^-1，其中苯并[b]荧蒽的含量最高，致癌性PAHs占总量的51．9％。PAHs在深圳不同土地利用类型的土壤中的含量由高到低的次序为：菜园地，城区，果园地，林地。PAHs主要来源于燃烧来源，果园地、林地中的PAHs主要来源于长距离的大气迁移，部分城区土壤指示有石油来源。深圳市19．4％的土壤属重污染，重污染的土壤主要分布在菜园地和城区两类土壤中，城区表层土壤PAHs含量较国外其他城市低。结果对于认识PAHs在深圳土壤中的分布规律和环境迁移、以及如何控制PAHs污染具有重要的意义。

Sixteen prior PAHs compounds were measured by gas chromatography equipped with a mass spectrometry detector for totally 36 surface soil samples （0-20 cm） collected from Shenzhen in January 2007. The result showed total PAHs ranged from 67.7-7 137.0 nggl with the average concentration of 664.7 ng·g^-1, and benzo[b]fluoranthene was the most abundant compound. The carcinogenic PAHs occupied the contribution of 51.9%. The concentration of ∑PAHs in the collected samples related to different land use types the order： vegetable soils〉urban〉orchard soils〉forest. The ratios ofFlur/（ Flur＋Pye ） and AN/（ AN＋Phen ） indicated that the PAHs in the surface soils were probably originated from the combustion of grass, wood, coal, and vehicle exhaust. And in some urban soils, petroleum might be the major contributors of PAHs. The levels of PAHs in Shenzhen soil was lower than those urban found in foreigh country, PAHs in orchard soils and forest were mainly come from long-range transport than with emissions from a local source. According to the recommendations or guidelines existed in worldwide, 19.4% of the samples in the present study were described as heavily contaminated, which were mostly distributed in vegetable soils and urban. Our studying is significant to understand characteristics of distribution, accumulation and transportation of PAHs in Shenzhen soil, which is useful to control PAHs pollution.