Geochemical distribution and removal of As, Fe, Mn and Al in a surface water system affected by acid mine drainage at a coalfield in Southwestern China

• Published in: Environmental Geology Vol. 57; no. 7; pp. 1457 - 1467
• Main Authors: Wu, Pan, Tang, Changyuan, Liu, Congqiang, Zhu, Lijun, Pei, TingQuan, Feng, Lijuan
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.06.2009; Springer Berlin Heidelberg; Springer; Springer Nature B.V
• Subjects: Acid mine drainage; Alkalinity; Aluminum; Coal; Coal mining; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Geochemistry; Geology; Heavy metals; Hydrogeology; Manganese; Metal concentrations; Mineralogy; Minerals; Natural attenuation; Original Article; Pollutants; Pollution, environment geology; Silicates; Sulfates; Surface water; Water geochemistry; Water quality; Southwest China; Far East; Asia; China; Guizhou China; China, People's Rep; Xingren coalfield; Hydrogeochemical characteristic; Acid mine drainage (AMD); Natural attenuation; Heavy metals; heavy metals; acide mine drainage; ferrous iron; coal seams; ground water; metals; aluminum; pollution; aquifers; pH; Mine drainage; anions; sulfides; carbonaceous rocks; coal fields; cations; dissolution; concentration; arsenic; alkalinity; pollutants; natural attenuation; surface water; sedimentary rocks; water-rock interaction; coal; iron
• ISSN: 0943-0105; 1866-6280; 1432-0495; 1866-6299
• DOI: 10.1007/s00254-008-1423-9

The chemical characteristics, formation and natural attenuation of pollutants in the coal acid mine drainage (AMD) at Xingren coalfield, Southwest China, are discussed in this paper based on the results of a geochemical investigation as well as geological and hydrogeological background information. The chemical composition of the AMD is controlled by the dissolution of sulfide minerals in the coal seam, the initial composition of the groundwater and the water-rock interaction. The AMD is characterized by high sulfate concentrations, high levels of dissolved metals (Fe, Al, Mn, etc.) and low pH values. Ca²⁺ and SO₄ ²⁻ are the dominant cation and anion in the AMD, respectively, while Ca²⁺ and HCO₃ ⁻ are present at significant levels in background water and surface water after the drainage leaves the mine site. The pH and alkalinity increase asymptotically with the distance along the flow path, while concentrations of sulfate, ferrous iron, aluminum and manganese are typically controlled by the deposition of secondary minerals. Low concentrations of As and other pollutants in the surface waters of the Xingren coalfield could be due to relatively low quantities being released from coal seams, to adsorption and coprecipitation on secondary minerals in stream sediments, and to dilution by unpolluted surface recharge. Although As is not the most serious water quality problem in the Xingren region at present, it is still a potential environmental problem.