title: A three-year experiment confirms continuous immobilization of cadmium and lead in contaminated paddy field with biochar amendment.
abstract: Heavy metal contamination in croplands has been a serious concern because of its high health risk through soil-food chain transfer. A field experiment was conducted in 2010-2012 in a contaminated rice paddy in southern China to determine if bioavailability of soil Cd and Pb could be reduced while grain yield was sustained over 3 years after a single soil amendment of wheat straw biochar. Contaminated biochar particles were separated from the biochar amended soil and microscopically analyzed to help determine where, and how, metals were immobilized with biochar. Biochar soil amendment (BSA) consistently and significantly increased soil pH, total organic carbon and decreased soil extractable Cd and Pb over the 3 year period. While rice plant tissues' Cd content was significantly reduced, depending on biochar application rate, reduction in plant Pb concentration was found only in root tissue. Analysis of the fresh and contaminated biochar particles indicated that Cd and Pb had probably been bonded with the mineral phases of Al, Fe and P on and around and inside the contaminated biochar particle. Immobilization of the Pb and Cd also occurred to cation exchange on the porous carbon structure.
authors.affiliation: Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China.
authors.forename: Rongjun
authors.initials: R
authors.lastname: Bian
authors.affiliation: Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China; School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia; Discipline of Chemistry, University of Newcastle, Callaghan, NSW 2308, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Joseph
authors.affiliation: Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Cui
authors.affiliation: Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China. Electronic address: pangenxing@aliyun.com.
authors.forename: Genxing
authors.initials: G
authors.lastname: Pan
authors.affiliation: Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China.
authors.forename: Lianqing
authors.initials: L
authors.lastname: Li
authors.affiliation: Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China.
authors.forename: Afeng
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW 2052, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: Rutlidge
authors.affiliation: Electron Microscope Unit, University of Newcastle, Callaghan, NSW 2308, Australia.
authors.forename: Singwei
authors.initials: S
authors.lastname: Wong
authors.affiliation: School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Chee
authors.initials: C
authors.lastname: Chia
authors.affiliation: Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW 2052, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Marjo
authors.affiliation: Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW 2052, Australia.
authors.forename: Bin
authors.initials: B
authors.lastname: Gong
authors.affiliation: School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Munroe
authors.affiliation: Discipline of Chemistry, University of Newcastle, Callaghan, NSW 2308, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Donne
mesh_terms: D000327:Adsorption; D018533:Biomass; D002104:Cadmium / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002606:Charcoal; D002681:China; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry*; D019216:Metals, Heavy / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry; D012275:Oryza; D012987:Soil; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D009930:Organic Chemicals; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002104:Cadmium; D002606:Charcoal; D007854:Lead; D002244:Carbon
keywords: Aged biochar; Biochar; Heavy metal pollution; Rice paddy; Soil remediation