title: Sulfate migration in a river affected by acid mine drainage from the Dabaoshan mining area, South China.
abstract: Sulfate, a major component of acid mine drainage (AMD), its migration in an AMD-affected river which located at the Dabaoshan mine area of South China was investigated to pursue the remediation strategy. The existing factors of relatively low pH values of 2.8-3.9, high concentrations of SO4(2-) (∼1940 mg L(-1)) and Fe(3+) (∼112 mg L(-1)) facilitated the precipitation of schwertmannite (Fe8O8(OH)6SO4·nH2O) in the upstream river. Geochemical model calculations implied the river waters were supersaturated, creating the potential for precipitation of iron oxyhydroxides. These minerals evolved from schwertmannite to goethite with the increasing pH from 2.8 to 5.8 along the river. The concentration of heavy metals in river waters was great reduced as a result of precipitation effects. The large size of the exchangeable sulfate pool suggested that the sediments had a strong capacity to bind SO4(2-). The XRD results indicated that schwertmannite was the predominant form of sulfate-bearing mineral phases, which was likely to act as a major sulfate sink by incorporating water-borne sulfate into its internal structure and adsorbing it onto its surface. The small size of reduced sulfur pools and strong oxidative status in the surface sediments further showed that SO4(2-) shifting from water to sediment in form of sulfate reduction was not activated. In short, precipitation of sulfate-rich iron oxyhydroxides and subsequent SO4(2-) adsorption on these minerals as well as water dilution contributed to the attenuation of SO4(2-) along the river waters.
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; School of Environmental and Biological Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, PR China.
authors.forename: Meiqin
authors.initials: M
authors.lastname: Chen
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China. Electronic address: lutao@scut.edu.cn.
authors.forename: Guining
authors.initials: G
authors.lastname: Lu
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China.
authors.forename: Chuling
authors.initials: C
authors.lastname: Guo
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
authors.forename: Chengfang
authors.initials: C
authors.lastname: Yang
authors.affiliation: School of Environmental and Biological Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, PR China.
authors.forename: Jingxiong
authors.initials: J
authors.lastname: Wu
authors.affiliation: School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901, USA.
authors.forename: Weilin
authors.initials: W
authors.lastname: Huang
authors.affiliation: School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Yee
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, PR China. Electronic address: chzdang@scut.edu.cn.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Dang
mesh_terms: D000327:Adsorption; D002681:China; D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry; D008906:Mining; D045483:Rivers / Q000737:chemistry*; D013431:Sulfates / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D019216:Metals, Heavy; D013431:Sulfates; D014874:Water Pollutants, Chemical
keywords: AMD-affected river; Iron oxyhydroxide; Mining area; migration