珠江三角洲地区主要树种叶片多环芳烃含量特征及影响因素分析

Concentrations and Influence Factors of Polycyclic Aromatic Hydrocarbons in Leaves of Dominant Species in the Pearl River Delta,South China

应用气相色谱-质谱联用方法测定了珠江三角洲地区6种主要树种叶片多环芳烃(PAHs)的含量,并对相应的叶脂含量、叶面积、比叶面积进行了测定,探讨了叶片PAHs含量特征和种间差异的影响因素.结果显示,松针PAHs含量显著高于阔叶,马尾松松针含量最高(1 034.7 ng.g-1),荷木含量最低(199.7 ng.g-1).在所有样品中,芴、菲、荧蒽、芘、为主要的PAHs组分,3、4环PAHs含量占∑PAHs的80%以上,各环化合物与∑PAHs在不同显著性水平上呈显著正相关关系.按脂含量计算PAHs含量能大大缩小种间含量的差异,高、低值相差约2倍(分别为6.8 ng.mg-1和2.7 ng.mg-1);按单位叶面积计算的PAHs含量进一步扩大了种间差异,最高值(15.3 ng.cm-2)约最低值(1.9 ng.cm-2)的8倍.进一步分析表明,∑PAHs、3环PAHs、4环PAHs与脂含量呈良好线性正相关关系、与比叶面积表现出一定的线性负相关关系,显示两者是影响叶片PAHs含量种间差异的重要因素.

Concentrations of PAHs in leaves of six dominant species in the Pearl River Delta of South China were determined with gas chromatography and mass spectrometry（GC-MS）,and synchronously leaf-lipid contents,leaf areas,specific leaf areas（SLA） were measured.The characters of PAHs abundance and influence factors on them were investigated.The results show that concentrations of PAHs in pine needles are higher than those in broad-leaves remarkably,and the highest value（1034.7ng·g^-1） in Pinus massoniana） is fivefold of the lowest（199.7ng·g^-1） in Schima superba）.Flu,Phe,Fluo,Pyr,Chr are the main components of ∑PAHs,and the concentrations of 3-ring and 4-ring PAHs exceed 80% of the total PAHs.Significant positive correlations between the components and ∑PAHs were also detected.The PAHs contents by per lipid could reduce inter-species variance obviously,and the diversity is no more than two times（6.8（ng·mg^-1） and 2.7（ng·mg^-1）,respectively）.Adversely,the PAHs contents by per cm^2 magnify inter-species variance,and the highest value（15.3（ng·cm^-2） ascends to eight times of the lowest（1.9ng·cm^-2）.Furthermore,significant positive correlation between PAHs and leaf-lipid contents was identified,as well as negative correlation between PAHs and specific leaf areas.All of these indicate that leaf-lipid contents and specific leaf areas are two significant factors which influenced PAHs contents in leaves.