Release dynamics of As, Co, and Mo in a biochar treated soil under pre-definite redox conditions
Journal
Science of the Total Environment
Journal Volume
657
Journal Volume
657
Pages
686-695
Start Page
686
End Page
695
ISSN
00489697
Date Issued
2019-03-20
Author(s)
Abstract
This study assessed the impact of pre-definite redox potential (EH) on the release dynamics and distribution of As, Co, and Mo between the dissolved and colloidal phases as well as their potential mobility and phytoavailability in the sediment phase of a mining soil treated with rice hull biochar (BC). The experiment was conducted from controlled moderately-reducing to oxidizing conditions using an automated biogeochemical microcosm system. Arsenic and Mo were more abundant in the dissolved phase due to their predominant in potential mobile fractions, while Co was more abundant in the colloidal phase due to its association with Fe-(hydr)oxides. Biochar increased the dissolved and colloidal concentrations of As, the dissolved concentration of Co, and the colloidal concentration of Mo under oxidizing condition. On the other hand, the application of BC decreased the dissolved concentration of Mo and the colloidal concentration of Co in the first redox cycle under reducing-acidic condition, due to lower pH values, and chemistry of sulfide-sulfate and Fe/Mn oxides. The phytoavailability of As and Co were higher than their potential mobility in the sediment phase, while the same trend was not discerned for Mo. The potential mobility and phytoavailability of As and Co were high under oxic-acidic conditions. The potential mobility and phytoavailability of Mo might be increased under oxic condition due to the dissolution of Fe and Mn oxides under lower pH conditions, especially in the BC treated soil. Application of such rice hull BC to soil might stimulate the release of As, Co, and Mo under flooding conditions, which might increase the environmental and health risks in such wetland ecosystems.
Subjects
Black carbon
Sediment
Soil contamination
Trace elements
Wetland ecosystem
Other Subjects
Colloids; Dissolution; Ecosystems; Health risks; Iron oxides; pH; Redox reactions; Sediments; Soils; Sulfur compounds; Trace elements; Wetlands; Black carbon; Colloidal concentrations; Dissolved concentrations; Environmental and health risks; Oxidizing conditions; Potential mobility; Soil contamination; Wetland ecosystem; Cobalt; arsenic; biochar; charcoal; cobalt; dissolved organic carbon; ferric hydroxide; iron oxide; manganese oxide; molybdenum; organic carbon; sulfate; sulfide; unclassified drug; arsenic; biochar; charcoal; cobalt; molybdenum; arsenic; biochar; black carbon; cobalt; molybdenum; redox conditions; soil pollution; soil remediation; trace element; wetland; Article; biogeochemical cycle; biogeochemistry; colloid; concentration (parameters); controlled study; dissolution; flooding; microcosm; oxidation; oxidation reduction potential; oxidation reduction reaction; pH; physical chemistry; phytoavailability; priority journal; soil amendment; soil pollution; analysis; bioavailability; chemistry; China; ecosystem restoration; mining; pharmacokinetics; soil pollutant; Arsenic; Biological Availability; Charcoal; China; Cobalt; Colloids; Environmental Restoration and Remediation; Hydrogen-Ion Concentration; Mining; Molybdenum; Oxidation-Reduction; Soil Pollutants
Publisher
Elsevier B.V.
Type
journal article