title: Does ochre have the potential to be a remedial treatment for As-contaminated soils?
abstract: Ochre is an iron oxyhydroxide-rich waste that accumulates in water bodies associated with disused mines. Laboratory experiments were conducted to examine the potential of four different ochres to be used as remedial agents for As contaminated soils. The ochres removed As from solution (200 and 500 mg L(-1)) in adsorption experiments at pH 3 and 8 and, when added to As contaminated soil (5% w/w) significantly reduced As release to solution. In both these experiments the highest surface area ochres performed best. The impact of ochre amendments on uptake of As from soil by plants and humans and release of As to ground water was assessed in a year-long incubation study. Ochres increased soil pH and reduced CaCl2 extractable As but had no consistent effect on plant growth, plant As uptake or As extraction in physiologically-based extraction tests. Ochre may be better used for water treatment than soil remediation.
authors.affiliation: Soil Research Centre, Dept. Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, University of Reading, RG6 6AB, UK; Department of Soil and Environmental Management, Faculty of Agriculture, Kogi State University, P.M.B. 1008 Anyigba, Kogi State, Nigeria. Electronic address: joeolimah@gmail.com.
authors.forename: J A
authors.initials: JA
authors.lastname: Olimah
authors.affiliation: Soil Research Centre, Dept. Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, University of Reading, RG6 6AB, UK.
authors.forename: L J
authors.initials: LJ
authors.lastname: Shaw
authors.affiliation: Environment Department, University of York, York, YO10 5DD, UK.
authors.forename: M E
authors.initials: ME
authors.lastname: Hodson
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry*; D060587:Groundwater / Q000737:chemistry; D006801:Humans; D010944:Plants / Q000378:metabolism; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D005290:Ferric Compounds; D012987:Soil; D012989:Soil Pollutants; C021024:ferric hydroxide; D001151:Arsenic
keywords: Arsenic; Bioassays; Contaminated soil; Incubation; Ochre