Natural and synthesised iron-rich amendments for As and Pb immobilisation in agricultural soil |
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Authors: | Yaser A Almaroai Meththika Vithanage Anushka Upamali Rajapaksha Sang Soo Lee Xiaomin Dou Young Han Lee |
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Institution: | 1. Department of Biological Environment, Kangwon National University, Chuncheon, Korea;2. Department of Biology, Umm Al-Qura University, Makkah, Saudi Arabia;3. Chemical and Environmental Systems Modeling Research Group, Institute of Fundamental Studies, Kandy, Sri Lanka;4. Department of Environmental Science and Engineering, Beijing Forestry University, Beijing, PR China;5. Division of Plant Environmental Research, Gyeongsangnam-do Agricultural Research and Extension Service, Jinju, Korea |
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Abstract: | The immobilisation of heavy metals in contaminated soils is a promising alternative to conventional remediation techniques. Very few studies have focused on the use of iron-rich nanomaterials and natural materials for the adsorption of toxic metals in soils. Synthesised iron-rich nanomaterials (Fe and Zr–Fe oxides) and natural iron-rich materials (natural red earth; NRE) were used to immobilise As and Pb in contaminated agricultural soil. Total concentrations of As and Pb in the initial soil (as control) were 170.76 and 1945.11 mg kg?1, respectively. Amendments were applied into the soil at 1, 2.5 and 5% (w/w) in triplicate and incubated for 150 days. Except for the NRE-amended soil, soil pH decreased from 5.6 to 4.9 with increasing application rates of Fe and Zr–Fe oxides. With addition of Fe and Zr–Fe oxides at 5%, the ammonium acetate (NHO4Ac)-extractable Pb was greatly decreased by 83 and 65% compared with NRE addition (43%). All subjected amendments also led to a decrease in NHO4Ac-extractable As in the soils, indicating the high capacity of As immobilisation. Soil amended with NRE showed a lower ratio of cy19:0 to 18:1ω7c, indicating decreased microbial stress. The toxicity characteristic leaching procedure produced results similar to the NHO4Ac extraction for As and Pb. The NRE addition is recommended for immobilising heavy metals and maintaining biological soil properties. |
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Keywords: | bioavailability stabilisation nanoparticle adsorbent remediation soil quality |
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