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.