Abstract: Surface sediments were sampled from the mangrove wetland in Quanzhou Bay to study the distribution, speciation, and bio-availability of mercury in the sediments. The total mercury content in the sediments ranged in 0.03-0.22 mg·kg^-1, which met the first class standard of Marine Sediment Quality (GB 18668-2002), with the exception of that at site 14. The average proportion of different speciation mercury to total mercury in the sediments presented a sequence of oxidizable (84.0%) > residual (14.0%) > reducible (1.8%) > weak acid soluble (0.2%). The relatively high bio-availability of mercury in the sediments indicated certain potential hazard to the mangrove ecosystem.

Key words: Vetiveria zizanioids, Eutrophication, Purification of water body