松针生理性质对其富集多环芳烃行为的影响

测定了雪松(Cedrus deodar)和黑松(Pinus thunbergii)松针的脂含量、气孔密度和比表面积等生理性质及松针中多环芳烃 (PAHs)浓度,考察了松针生理性质对其富集PAHs行为的影响.结果表明,雪松松针中PAHs浓度高于黑松,其平均总浓度(ΣPAHs)分别为(1101±692)ng/g和(518±339)ng/g,2种松针对PAHs的富集能力有较大差异,脂含量是决定松针富集PAHs量的首要因素.2种松针中PAHs组成均以3环和4环PAHs为主,分别占ΣPAHs的56%和31%以上.松针对于3环PAHs的富集能力强于4环PAHs,两者浓度差异约为2倍左右;对于5、6环PAHs,未发现其浓度与脂含量之间的相关关系.由于雪松和黑松松针的脂含量随比表面积具有不同的变化趋势,2种松针中PAHs浓度随比表面积的变化趋势相反.对于5、6环PAHs,松针比表面积和气孔密度对其浓度有显著影响.

Influences of Pine Needles Physiological Properties on the PAH Accumulation

The lipid contents, specific surface areas and stomata density of two kinds of pine (Cedrus deodar and Pinus thunbergii) needles were determined simultaneously with the levels of polycyclic aromatic hydrocarbons (PAHs). The influences of the physiological properties of two species on the accumulation of PAHs in pine needles were investigated. The PAH concentrations in Cedrus deodar needles are higher than that in Pinus thunbergii needles, and the average total PAH concentrations (PAHs) in two species are (1 101 +/- 692) ng/g and (518 +/- 339) ng/g, respectively. The capabilities of accumulating PAHs for two species are different. The lipid content is the principal factor influencing the levels of pine needle PAHs. In Cedrus deodar and Pinus thunbergii needles, 3-ring (> 56%) and 4-ring (> 31%) PAHs make up large proportions of sigma PAHs. The accumulation capabilities of pine needles for 3-ring PAHs are greater than 4-ring PAHs, and the concentrations of 3-ring PAHs are about two times of those of 4-ring PAHs. There are no significant correlations between the levels of 5- and 6-ring PAHs and lipid contents for two species. For two species, the correlations between lipid contents and specific surface areas are different, which results in the contrary correlations between the PAH levels and specific surface areas for Cedrus deodar and Pinus thunbergii. Specific surface areas and stomata density affect the levels of 5- and 6-ring PAHs in pine needles significantly.