POLLUTION CHARACTERISTICS AND ECOLOGICAL RISK ASSESSMENT OF HEAVY METALS AND POLYCYCLIC AROMATIC HYDROCARBONS(PAHs) IN SEDIMENT FROM XIAMEN BAY

Heavy metal and polycyclic aromatic hydrocarbons(PAHs) are often present together in sediment environment,and their combined pollution has become one of the important directions of environmental sciences.Bottom surface sediments from 12 stations within Xiamen bay were analyzed for Cu,Zn,Pb,Zn,Cr,Cd and 16 priority PAHs.The results indicated that As,Pb and Cu were grouped between the effects range-low(ERL) and effects range-median(ERM),and Zn,Cr,Cd,Hg were grouped below ERL at most sites.Total PAH levels were far below ERL of 4000 μg·kg-1,and both petrogenic and pyrogenic inputs were significant to the observed PAH levels.The results that have shown a good correlation between heavy metals and low-ring PAHs indicated that they have similar chemical behaviours in the environment.By applying of mean Effects Range Median quotients(mERM-Q),it was found that the Yundang Lagoon with mERM-Q value close to 0.5 would be expected to have the greatest potential toxic risk in amphipod within Xiamen bay and its adjacent areas.