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Chou M.-L.,National Cheng Kung University | Jean J.-S.,National Cheng Kung University | Yang C.-M.,Taiwan Agricultural Research Institute | Hseu Z.-Y.,National Taiwan University | And 4 more authors.
Journal of Geochemical Exploration | Year: 2016

Chemical immobilization of arsenic (As) in contaminated sites may be achieved through the use of inorganic and organic soil amendments to reduce its bioavailability. The chemical immobilization of As-rich soil by using ethylenediaminetetraacetic acid ferric sodium salt (EDTA-Fe) and calcium peroxide (CaO2) as stabilizing agents was investigated in Chianan plain of southwestern Taiwan. The As-rich soil was amended with EDTA-Fe, at the rates of 0, 0.35, 0.7 and 1.4 Mg ha-1, or with CaO2, at the rates of 0, 0.38, 0.76 and 1.52 Mg ha-1, and grown with radish (Raphanus sativus L.), lettuce (Lactuca sativa), Chinese cabbage (Brassica rapa) and Arden lettuce (Lactuca sativa L.). Results showed that those amended with EDTA-Fe at 0.35 and 0.7 Mg ha-1 can significantly reduce As accumulation in vegetables. Moreover, the uptake of As in vegetables decreased more in soil amended with CaO2 relative to that amended with EDTA-Fe. The topsoil amended with EDTA-Fe and CaO2 can significantly increase As chemisorption by oxides and hydroxides of Fe and Al on the soil surface. As indicated, applications of EDTA-Fe at the rate of 0.7 Mg ha-1 and CaO2 at the rate of 1.52 Mg ha-1 can obtain optimal effect on suppressing As uptake by vegetables. As a result, both EDTA-Fe and CaO2 proved to be effective in immobilizing As in the soil and thus can maintain nutrient balance of vegetables grown in As-rich soil, though CaO2 application obtained a better result. © 2016 Elsevier B.V. Source

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