Distribution and sources of polycyclic aromatic hydrocarbons in sediments of Pan Hangzhou bay

Polycyclic aromatic hydrocarbons (PAHs) surface sediment samples were collected from the Pan Hangzhou Bay at 36 sites from 2011 to 2014.The concentration level,spatial distribution,composition structure and possible sources of PAHs were investigated.The results implied that the survey sea area was at a moderate PAHs pollution level with average concentrations of (116.03±15.26) ×10^-9,(106.59±13.90)×10^-9,(129.05±14.37)×10^-9 and (106.10±10.43)×10^-9 in sequence by year.The distribution of PAHs level showed a decrease trend from inshore to offshore with high patches mainly located around the Yangtze River Estuary and the Zhoushan Coast.Phenanthrene dominated in concentration out of the 16 priority PAHs and the proportion of 3~5 rings-PAHs was much high.The source analysis implied that PAHs were mainly from the combustion of coal,wood and biomass,with some stations affected by oil leakage.