Abstract: Sediment samples were collected from the south branch of Yangtze River estuary in May and October 2008, and their polycyclic aromatic hydrocarbons (PAHs) concentrations were analyzed by HPLC, aimed to study the distribution, sourc
e, and ecological risk of the PAHs. The total concentration of PAHs in the sediments ranged in 8.9-312.2 ng·g^-1, and the PAHs were mainly constituted by Pyr, Phe, BbF, BaA, and BaP, with the highest concentration of Pyr. The total concentration of PAHs in test sediments was very similar to the published data for the Yangtze River estuary, Huanghe River estuary, and Yalu River estuary, but was significantly lower than those for the Pearl River estuary, Mingjiang River estuary, and tidal flats of Yangtze River estuary. In the PAHs, those with 4-6 rings were the dominant, suggesting that the main source of the PAHs was of pyrogenic. The assessment by the method of mean effects median quotient demonstrated that the PAHs in test sediments had very low probability (<10%) of ecological risk.

Key words: AM fungus, Na-phytate, ALP, Extraradical hyphae