The influence of redox chemistry and pH on chemically active forms of arsenic in sewage sludge-amended soil
- Louisiana State Univ., Baton Rouge, LA (United States). Wetland Biogeochemistry Inst.
- Univ. Miguel Hernandez, Alicante (Spain). Div. Tecnologia de Alimentos
- Mahidol Univ., Bangkok (Thailand). Environmental Health Science Dept.
- Kasetsart Univ., Bangkok (Thailand). Dept. of Environmental Science
Chemical fractionation procedures were used to quantify the effect of the sediment redox and pH conditions on the adsorption and solubility of arsenic (As) in municipal sewage sludge and sewage sludge-amended soil. Sludge and sludge-amended soil were incubated in microcosms in which Eh-pH conditions were controlled. Samples were sequentially extracted to determine As in various chemical forms (water soluble, exchangeable, bound to carbonates, bound to iron (Fe) and manganese (Mn) oxides, bound to insoluble organics and sulfides) and the chemically inactive fraction (mineral residues). In both sewage sludge and sludge-amended soil, As chemistry was governed by large molecular humic matter and sulfides and Fe and Mn-oxides. Solubility of As remained low and constant under both aerobic and anaerobic conditions in sludge-amended soil. After dissolution of Fe and Mn-oxides, As{sup 5+} was released into sludge solution, reduced to As{sup 3+} and likely precipitated as sulfide. Therefore, an organic amendment rich in sulfur compounds, such as sewage sludge, would drastically reduce the potential risks derived from As pollution under highly anoxic conditions by precipitation of this toxic metalloid as insoluble and immobile sulfides.
- OSTI ID:
- 684514
- Journal Information:
- Environment International, Vol. 25, Issue 5; Other Information: PBD: Jul 1999
- Country of Publication:
- United States
- Language:
- English
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