title: Concentrations of inorganic arsenic in groundwater, agricultural soils and subsurface sediments from the middle Gangetic plain of Bihar, India.
abstract: Concentrations of inorganic forms [arsenite, As(III) and arsenate, As(V) of arsenic (As) present in groundwater, agricultural soils and subsurface sediments located in the middle Gangetic plain of Bihar, India were determined. Approximately 73% of the groundwater samples (n=19) show As(III) as the dominant species while 27% reveals As(V) was the dominant species. The concentration of As(III) in agricultural soil samples varies from not detectable to 40μg/kg and As(V) was observed as the major species (ranging from 1050 to 6835μg/kg) while the total As concentration varied from 3528 to 14,690μg/kg. Total extracted concentration of As was higher in the subsurface sediments (range 9119-20,056μg/kg in Methrapur and 4788-19,681μg/kg in Harail Chapar) than the agricultural soil, indicating the subsurface sediment as a source of As. Results of X-ray diffraction (XRD) and environmental scanning electron microscope (ESEM) revealed the presence of hematite and goethite throughout the vertical section below while magnetite was observed only in the upper oxidized layer at Methrapur and Harail Chapar. Alteration of Fe-oxides and presence of fibrous goethite indicating presence of diagenetic sediment. Siderite plays a crucial role as sinks to the As in subsurface sediments. The study also concluded that decomposition of organic matter present in dark and grey sections promote the redox conditions and trigger mobilization of As into groundwater.
authors.affiliation: Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), University of Newcastle, ATC Building, University Drive, Callaghan, NSW 2308, Australia; School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
authors.forename: Manoj
authors.initials: M
authors.lastname: Kumar
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
authors.forename: A L
authors.initials: AL
authors.lastname: Ramanathan
authors.affiliation: Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), University of Newcastle, ATC Building, University Drive, Callaghan, NSW 2308, Australia.
authors.forename: Mohammad Mahmudur
authors.initials: MM
authors.lastname: Rahman
authors.affiliation: Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), University of Newcastle, ATC Building, University Drive, Callaghan, NSW 2308, Australia. Electronic address: ravi.naidu@crccare.com.
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
mesh_terms: D001151:Arsenic / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D060587:Groundwater / Q000737:chemistry*; D007194:India; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D001151:Arsenic
keywords: Agricultural soil; Extractable arsenic; Inorganic arsenic; Middle Gangetic plain; Subsurface sediments