深圳湾生态系统多环芳烃(PAHs)特征及其生态危害

2004年在深圳湾海域采集海水、悬浮物、表层沉积物和柱状沉积物样品,并分析其中15种多环芳烃的含量及其相关参数,同时采用210Pb法测定柱状沉积物的年龄.结果表明,海水、悬浮物、表层沉积物和柱状沉积物中总的PAHs含量分别为(69.4±24.7)ng·L-1、(429.1±231.8)ng·g-1、(353.8±128.1)ng·g-1和(321.1±134.6)ng·g-1,各介质优势组分均为菲、荧蒽和芘;1948～2004年期间,深圳湾柱状沉积物中PAH各单体的浓度总体上一直在增加,PAHs的平均沉积通量为89.9ng/(cm2·a);PAH各单体在沉积物/海水中的分配系数(Koc)与其相应的辛醇/水比(Kow)存在明显的正相关性,即可用PAH的Kow值来预测深圳湾海域PAH的Koc.目前,水体与沉积物中PAH含量对该海域的水生生物尚未构成威胁.

Characteristics of PAHs in the Ecosystem of Deep Bay and Their Ecological Risk

Seawater, suspended particulate matter (SPM), surface sediment and core sediment samples from Deep Bay in 2004 were collected and 15 PAH isomers concentrations and relative parameters were analyzed, while the age of core sediment was also detected by use of the ²¹⁰Pb dating method. The results demonstrated that total PAHs concentrations in seawater, SPM, surface sediment and core sediment were (69.4±24.7) ng·L^-1, (429.1±231.8) ng·g^-1, (353.8±128.1) ng·g^-1 and (321.1±134.6) ng·g^-1, respectively. Predominant components in all above compartments were phenanthrene, fluoranthene and pyrene. Temporal trend of PAH concentrations in core sediment generally increased from 1948 to 2004, with the mean PAHs sedimentation flux of 89.9 ng/(cm²·a). Significant positive correlations between partition coefficients (K_oc), which was defined as the ratio of PAH isomers concentrations in surface sediment to those in seawater, and their octanol/water partition coefficients (K_ow) were observed, i. e., the sorption constant K_oc of PAHs in the bay may be predicted by the K_ow for the compounds analyzed. For the time being, there is not potential threat to aquatic organisms for PAH concentrations both in water and sediment in Deep Bay.