Abstract: Under laboratory conditions, this paper studied the adsorption of different concentration (40, 400 and 4 000 μg·L^-1) polycyclic aromatic hydrocarbons (PAHs) including low molecular weight acenaphthylene, phenathrene and chrysene and high molecular weight benzo［g,h,i］perylene in seawater by the leaf litters of Kandelia candel and Avicennia marina at different decomposition status. The results showed that at the same concentrations, the total amount of test PAHs adsorbed by the K. candel and A. marinaleaf litters had no significant difference, in spite of their decomposition status. The adsorbed amount of the PAHs tended to increase with their increasing concentrations. The litters had a higher adsorption rate of or exhibited selective adsorption to phenathrene and chrysene when the PAHs concentrations were lower, and had a higher adsorption rate of benzo［g,h,i］perylene when the PAHs concentrations were higher. These results indicated that mangrove leaf litter at different decomposition status had higher adsorption rates of PAHs in seawater. It is suggested that cleaning up the mangrove leaf litter in time could be one of the most effective ways to remove PAHs from seawater.

Key words: Wheat, Root activity, Flag leaf, Senescence