Back to Search
Start Over
Geochemical processes controlling fate and transport of arsenic in acid mine drainage (AMD) and natural systems
- Source :
- Journal of Hazardous Materials. 165:13-26
- Publication Year :
- 2009
- Publisher :
- Elsevier BV, 2009.
-
Abstract
- Acid mine drainage (AMD) is often accompanied with elevated concentrations of arsenic, in the forms of arsenite, As(III), and/or arsenate, As(V), due to the high affinity of arsenic for sulfide mineral ores. This review summarizes the major geochemical processes controlling the release, speciation, fate, and distribution of inorganic arsenic in mine drainage and natural systems. Arsenic speciation depends highly on redox potential and pH of the solution, and arsenite can be oxidized to the less toxic arsenate form. Homogeneous oxidation of arsenite occurs rather slowly while its heterogeneous oxidation on mineral surfaces can greatly enhance the reaction rates. Little evidence suggests that precipitation reaction limits the concentrations of arsenic in natural water, while co-precipitation may lead to rapid arsenic removal when large amount of iron hydroxides precipitate out of the aqueous phase upon neutralization of the mine drainage. Both arsenate and arsenite adsorb on common metal oxides and clay minerals through formation of inner-sphere and/or outer-sphere complexes, controlling arsenic concentration in natural water bodies. Arsenite adsorbs less strongly than arsenate in the typical pH range of natural water and is more mobile. Part of the adsorbed arsenic species can be exchanged by common anions (e.g., PO(4)(3-) and SO(4)(2-)), especially phosphate, which leads to their re-mobilization. Understanding the geochemistry of arsenic is helpful for predicting its mobility and fate in AMD and natural systems, and for designing of cost-effective remediation/treatment strategies to reduce the occurrence and risk of arsenic contamination.
- Subjects :
- Environmental Engineering
Sulfide
Environmental remediation
Health, Toxicology and Mutagenesis
chemistry.chemical_element
Mining
Arsenic
chemistry.chemical_compound
Water Movements
Chemical Precipitation
Environmental Chemistry
Waste Management and Disposal
Arsenite
chemistry.chemical_classification
Drainage, Sanitary
Arsenate
Environmental engineering
Phosphate
Acid mine drainage
Pollution
Arsenic contamination of groundwater
chemistry
Environmental chemistry
Adsorption
Water Pollutants, Chemical
Subjects
Details
- ISSN :
- 03043894
- Volume :
- 165
- Database :
- OpenAIRE
- Journal :
- Journal of Hazardous Materials
- Accession number :
- edsair.doi.dedup.....711c7f74bda51a707179f17eca9864bf