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Geochemical processes controlling fate and transport of arsenic in acid mine drainage (AMD) and natural systems

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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., PO43− and SO42−), especially phosphate, which leads to their re-mobilization. Understanding the geochemistry of arsenic is helpful for predicting its mobility and fate inAMDand natural systems, and for designing of costeffective
remediation/treatment strategies to reduce the occurrence and risk of arsenic contamination.

Keywords:
Arsenate
Arsenite
Fate and transport
Acid mine drainage (AMD)
Sorption

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Informasi Detail

Judul Seri

Journal of Hazardous Materials

No. Panggil

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Penerbit

London : Elsevier B.V.., 2009

Deskripsi Fisik

Journal of Hazardous Materials 165 (2009) 13–26

Bahasa

English

ISBN/ISSN

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Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

LINGKUNGAN HIDUP

Info Detail Spesifik

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Pernyataan Tanggungjawab

agus

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