title: Heavy metal contamination in a vulnerable mangrove swamp in South China.
abstract: Concentrations of six heavy metals (Cu, Ni, Zn, Cd, Cr, and Pb) in sediments and fine roots, thick roots, branches, and leaves of six mangrove plant species collected from the Futian mangrove forest, South China were measured. The results show that both the sediments and plants in Futian mangrove ecosystem are moderately contaminated by heavy metals, with the main contaminants being Zn and Cu. All investigated metals showed very similar distribution patterns in the sediments, implying that they had the same anthropogenic source(s). High accumulations of the heavy metals were observed in the root tissues, especially the fine roots, and much lower concentrations in the other organs. This indicates that the roots strongly immobilize the heavy metals and (hence) that mangrove plants possess mechanisms that limit the upward transport of heavy metals and exclude them from sensitive tissues. The growth performance of propagules and 6-month-old seedlings of Bruguiera gymnorhiza in the presence of contaminating Cu and Cd was also examined. The results show that this plant is not sufficiently sensitive to heavy metals after its propagule stage for its regeneration and growth to be significantly affected by heavy metal contamination in the Futian mangrove ecosystem. However, older mangrove seedlings appeared to be more metal-tolerant than the younger seedlings due to their more efficient exclusion mechanism. Thus, the effects of metal contamination on young seedlings should be assessed when evaluating the risks posed by heavy metals in an ecosystem.
authors.affiliation: State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
authors.forename: Yutao
authors.initials: Y
authors.lastname: Wang
authors.forename: Qiu
authors.initials: Q
authors.lastname: Qiu
authors.forename: Guorong
authors.initials: G
authors.lastname: Xin
authors.forename: Zhongyi
authors.initials: Z
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Zheng
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Ye
authors.forename: Shaoshan
authors.initials: S
authors.lastname: Li
mesh_terms: D002681:China; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D053833:Wetlands
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical