北京市常用常绿树种冬季叶片多环芳烃含量及其富集特征

为了解北京市常用常绿植物对大气污染物多环芳烃的富集能力，以陶然亭公园和马甸公园为样地，运用液相色谱法测定了9种健康生长的常绿植物冬季叶片中多环芳烃的含量，并对比分析了其中4种植物在不同样地的富集能力差异。结果显示:同一样地叶片多环芳烃富集特征存在种间差异。陶然亭公园9种植物叶片中，白皮松叶片中多环芳烃的总含量最高，叶片多环芳烃总含量排序为白皮松>雪松>华山松>侧柏>油松>粗榧>沙地柏>圆柏>白扦，其中白皮松叶片内轻环多环芳烃含量最高，白扦的含量最低；粗榧叶片内中环多环芳烃含量最高，沙地柏的含量最低；油松叶片内重环多环芳烃含量最高，圆柏的含量最低。马甸公园与陶然亭公园相同的4种植物，其叶片中多环芳烃的总含量排序相同，即:白皮松>侧柏>油松>圆柏，但同一树种在不同样地表现出叶片内多环芳烃组成不同。结果表明，常绿植物对多环芳烃有一定吸收能力，不同树种的富集量和富集组成有显著差异，从吸收有害污染物角度考虑，在城市绿化建设中进行相关树种筛选很有必要性。 

Content and absorption features of polycyclic aromatic hydrocarbons in the leaves of frequently-used evergreen trees in Beijing

To understand the absorption capacity of polycyclic aromatic hydrocarbons ( PAHs, a kind of air pollutant) from evergreen trees in Beijing, the contents of PAHs in the leaves from 9 kinds of evergreen trees in normal growth at Taoranting Park and Madian Park of Beijing in winter were measured by liquid chromatography, and a comparative analysis of 4 kinds of plants' absorption capacity in different sampling area was made. The results showed that:the absorption characteristics for PAHs from tested trees in the same sampling area was species dependent. The highest total content of PAHs was Pinus bungeana. The order of total PAHs content in different leaves at Taoranting Park from high to low was:Pinus bungeana >Cedrus deodara > Pinus armandii > Platycladus orientalis > Pinus tabuliformis > Cephalotaxus sinensis >Sabina vulgaris > Sabina chinensis > Picea meyeri, among which, the highest content of light PAHs was Pinus bungeana, while the minimum was Picea meyeri; Cephalotaxus sinensis had the most intermediate PAHs ,while Sabina vulgaris had the least; the content of heavy PAHs in Pinus tabuliformis was the maximum, and Sabina chinensis had the minimum content of heavy PAHs in leaves; The order of total PAHs content from four plants at Madian Park was the same as the content in leaves at Taoranting Park, which was Pinus bungeana > Platycladus orientalis > Pinus tabuliformis > Sabina chinensis;However,the four trees had different absorption features. The results indicate that evergreen trees can absorb PAHs from air, different trees have significantly different absorption content of PAHs and characteristics. In terms of absorption of harmful pollutants, the relevant tree species selection is necessary.