Characterization, sources and ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments from the mangroves of China

We characterized 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments of natural mangrove habitats in China, as well as assessed their sources and the risks they pose. Our results indicate that the total concentrations of the 16 PAHs ranged from 3.16 to 464.05 ng g(-1) dw (mean value of 72.80 ng g(-1) dw), which were generally lower than those in other coastal environments in China and in other countries. The compositional patterns were dominated by four-ring PAHs, including fluoranthene, pyrene, benzo[a]anthracene and chrysene. Petrogenic sources, specifically, petroleum spills, were the dominant sources of PAHs in the surficial sediments of mangroves in China. Selected ratios of PAHs from two-tailed Pearson correlation analysis and principal-component analysis for different sites also indicate pyrolytic sources of PAHs. Results of the ecological risk assessment show little negative effect of most of the PAHs in the surface sediments. Overall, the data obtained in this study reveal relative low PAHs pollution in the mangrove swamps of China.