title: [Mercury and copper accumulation during last fifty years and their potential ecological risk assessment in sediment of mangrove wetland of Shenzhen, China].
abstract: The processes of sediment transport and deposition can record some relative anthropogenic information in gulf region. Chronological analysis of the sediment core collected from mangrove wetland in Shenzhen Bay showed that the sedimentation rate was about 1.38 cm x a(-1). Soil buck density, pH, electrical conductivity (EC) and total organic carbon (TOC) changed in range of 0.36-0.71 g x cm(-3), 6-7, 2.93 x 10(3) -4.97 x 10(3) microS x cm(-1), and 1.5% - 3.8%, respectively. With the increase of soil depth, the soil buck density and EC increased gradually. However, the TOC decreased, with no significant change of pH. Contents of Hg and Cu in the whole depth of core ranged between 92-196 ng x g(-1) and 29-83 microg x g(-1), respectively. And both of them in sediment increased firstly and then decreased with the increasing soil depth. At 14 cm depth, contents of Hg and Cu reached up to the highest levels. Correspondingly, the ecological risk of Hg and Cu changed similarly with the contents of Hg and Cu. At 14 cm depth, the ecological risk indexes of Hg and Cu were at the highest levels of 39.10 and 13.85, respectively. The potential ecological risks of both Hg and Cu in sediments were mild. The rapid economical development of Hong Kong in 1960-1985 and Shenzhen in 1985-2000 contributed much to the Hg and Cu accumulation in mangrove wetland of Shenzhen Bay, China. Since the year of 2000, the reduction in contents of Hg and Cu has been expected as a consequence of the adoption of contamination control policies, improving the environment for growth of mangrove. In conclusion, the variations of core sediment heavy metal contents and its ecological risk assessment along the vertical profile reveal the interaction processes and extent of anthropogenic influences from the areas around the Shenzhen Bay and the catchments.
authors: School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen 518055, China. liruili@pkusz.edu.cn
authors: Rui-Li
authors: RL
authors: Li
authors: Min-Wei
authors: MW
authors: Chai
authors: Guo-Yu
authors: GY
authors: Qiu
authors: Bei
authors: B
authors: He
mesh_terms: D061006:Bays; D002681:China; D002947:Cities; D003300:Copper / Q000032:analysis*; D004785:Environmental Pollutants / Q000032:analysis*; D019015:Geologic Sediments / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D043982:Rhizophoraceae / Q000254:growth & development; D053833:Wetlands
chemical_list: D004785:Environmental Pollutants; D003300:Copper; D008628:Mercury