珠江广州段水体微表层与次表层中多环芳烃的分布与组成

Distribution and composition of polycyclic aromatic hydrocarbons in the surface microlayer and the subsurface microlayer from the Guangzhou Section of the Pearl River

2009年3月对珠江广州段微表层与次表层水中多环芳烃(PAHs)的分布与组成进行了研究.结果表明,珠江广州段微表层和次表层水中16种溶解态PAHs浓度为622.0～2132.2ng·L-1,与DOC存在正相关关系;颗粒态为316.7～639.5ng·L-1,与颗粒物浓度存在明显的线性相关;PAHs的组成以2～3环为主,溶解态中2～3环PAHs占总量的86.0%～95.7%,明显高于颗粒态中2～3环PAHs占总量的(68.8%～84.0%)百分比,PAHs的辛醇-水分配系数及其物理化学性质是造成这一差异的主要原因;微表层对PAHs有一定的富集作用,富集因数EF在1.1～1.5之间(溶解态1.2～1.5,颗粒态1.1～1.3).

Polycyclic aromatic hydrocarbons （PAHs） in water from the surface microlayer and the subsurface microlayer of the Guangzhou section of the Pearl River were studied in March 2009. The dissolved concentrations of 16 PAHs ranged from 622.0 to 2132.2 ng·L^-1,and there was a positive correlation between the concentrations of PAHs and the DOC. The particulate concentrations of PAHs ranged from 316.7 to 639.5 ng·L^-1,which were approximately linearly related to the concentrations of the particulates. Most of the PAHs contained 2 to 3 aromatic rings,and they accounted for 86.0% to 95.7% of the total PAHs in the dissolved phase. This was much higher than those observed in the particulate phase （68.8% to 84.0%）. The octanol-water partition coefficients and physicochemical properties of the PAHs contributed to the difference. The PAHs were found to be enriched in the microlayers and enrichment factors （EF） ranged from 1.1 to 1.5 （1.2 to 1.5 for dissolved and 1.1 to 1.3 for particulate）.