DISTRIBUTION OF POLYCYCLIC AROMATIC HYDROCARBONS IN WATER AND SEDIMENTS FROM DAYA BAY AND THEIR ECOLOGICAL HAZARD ASSESSMENT

Abstract

Sub-surface seawater and surface sediment samples at 14 sites in the sea area of the Daya Bay were collected in August of 1999 for the first time. 16 individual concentrations of polycyclic aromatic hydrocarbons (PAHs) were analyzed and their possible sources were discussed. The ecological hazards of typical PAHs were assessed. The results showed that the average content of PAHs was 10 984±8 461 ng·L~(-1) and varied from 4 228 to 29 325 ng·L~(-1) in the water, and 481±316 ng·g~(-1) and from 115 to 1 134 ng·g~(-1) (dry weight) in the sediments, respectively. In comparison with other offshore areas, the PAHs level in the water of the Daya Bay was relatively high. The individual composition of PAHs was characterized by 3 rings in the seawater and 4 rings in the se-(diments). The ratios of phenanthrene to anthracene and fluoranthene to pyrene suggested that PAHs in the sediments were derived from combustion of fossil fuels and petrogenic inputs. The average accumulation coefficient of PAHs across water-sediment was 72, and ranged from 9 to 756. The pollution of PAHs was serious in the water and light in the sediments, demonstrating that there were still a relatively large number of PAHs inputs. In order to keep sustainable development of marine ecosystem in the Daya Bay and protect human health, it is urgent to strengthen the monitoring of PAHs in the water and sediments, especially in the organisms in the sea area of the Daya Bay.