title: Slow pyrolyzed biochars from crop residues for soil metal(loid) immobilization and microbial community abundance in contaminated agricultural soils.
abstract: This study evaluated the feasibility of using biochars produced from three types of crop residues for immobilizing Pb and As and their effects on the abundance of microbial community in contaminated lowland paddy (P-soil) and upland (U-soil) agricultural soils. Biochars were produced from umbrella tree [Maesopsis eminii] wood bark [WB], cocopeat [CP], and palm kernel shell [PKS] at 500 °C by slow pyrolysis at a heating rate of 10 °C min-1. Soils were incubated with 5% (w w-1) biochars at 25 °C and 70% water holding capacity for 45 d. The biochar effects on metal immobilization were evaluated by sequential extraction of the treated soil, and the microbial community was determined by microbial fatty acid profiles and dehydrogenase activity. The addition of WB caused the largest decrease in Pb in the exchangeable fraction (P-soil: 77.7%, U-soil: 91.5%), followed by CP (P-soil: 67.1%, U-soil: 81.1%) and PKS (P-soil: 9.1%, U-soil: 20.0%) compared to that by the control. In contrast, the additions of WB and CP increased the exchangeable As in U-soil by 84.6% and 14.8%, respectively. Alkalinity and high phosphorous content of biochars might be attributed to the Pb immobilization and As mobilization, respectively. The silicon content in biochars is also an influencing factor in increasing the As mobility. However, no considerable effects of biochars on the microbial community abundance and dehydrogenase activity were found in both soils.
authors.affiliation: Korea Biochar Research Center & School of Natural Resources and Environmental Science, Kangwon National University, Chuncheon 24341, Republic of Korea.
authors.forename: Avanthi Deshani
authors.initials: AD
authors.lastname: Igalavithana
authors.affiliation: School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
authors.forename: Jinje
authors.initials: J
authors.lastname: Park
authors.affiliation: School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
authors.forename: Changkook
authors.initials: C
authors.lastname: Ryu
authors.affiliation: Division of Plant Environmental Research, Gyeongsangnam-do Agricultural Research & Extension Services, Jinju 52773, Republic of Korea.
authors.forename: Young Han
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Bioapplication and Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan.
authors.forename: Yohey
authors.initials: Y
authors.lastname: Hashimoto
authors.affiliation: Centre for Mined Land Rehabilitation, Sustainable Minerals Institute, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Longbin
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Environment and Energy, Sejong University, Seoul 05006, Republic of Korea.
authors.forename: Eilhann E
authors.initials: EE
authors.lastname: Kwon
authors.affiliation: Korea Biochar Research Center & School of Natural Resources and Environmental Science, Kangwon National University, Chuncheon 24341, Republic of Korea. Electronic address: soilok@kangwon.ac.kr.
authors.forename: Yong Sik
authors.initials: YS
authors.lastname: Ok
authors.affiliation: Korea Biochar Research Center & School of Natural Resources and Environmental Science, Kangwon National University, Chuncheon 24341, Republic of Korea. Electronic address: sslee97@kangwon.ac.kr.
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Lee
mesh_terms: D000383:Agriculture; D001419:Bacteria / Q000187:drug effects*; D002606:Charcoal / Q000737:chemistry*; D018556:Crops, Agricultural / Q000737:chemistry*; D004787:Environmental Pollution; D017745:Incineration; D008670:Metals / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000302:isolation & purification*; D013696:Temperature
chemical_list: D008670:Metals; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal
keywords: Black carbon; PLFA; Slow pyrolysis; Soil enzymes; Toxic metals