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| Immobilization of Cd and Pb using different amendments of cultivated soils around lead-zinc mines |
| Received:May 23, 2018 |
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| KeyWord:sepiolite;lime;humic acid;biochar;calcium magnesium phosphate;heavy metal;immobilization |
| Author Name | Affiliation | E-mail | | YUAN Xing-chao | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | LI Bo | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | ZHU Ren-feng | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | YAO Dong | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | ZHAN Fang-dong | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | CHEN Jian-jun | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | ZU Yan-qun | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | HE Yong-mei | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | LI Yuan | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | liyuan@ynau.edu.cn |
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| Abstract: |
| Field experiments and pot experiments were carried out to study the effects of sepiolite (S), lime (L), humic acid (H), biochar (B), and calcium magnesium phosphate fertilizer (P) on the remediation of cultivated soils planted with corn, in the vicinity of a lead-zinc mine in Yunnan. A BCR morphological classification experiment was used to study the variation in heavy metal fractions before and after the soil amendments. The results showed the following:The soil pH value significantly increased after lime and sepiolite treatments. The amendments significantly decreased the DTPA-extractable Cd and Pb. In the pot experiments, the highest immobilization efficiency of Cd for the biochar 45 t·hm-2 treatment was 45.3%, and that of Pb for lime 2.25 t·hm-2 was 60.6%. In the field experiments, the highest immobilization efficiency of Cd for calcium magnesium phosphate fertilizer 3 t·hm-2 was 48.3%, and that of Pb for lime 4.5 t·hm-2 was 25.3%. Lime, sepiolite, and biochar had significant effects on the fractions of heavy metals, that promoted the transformation of the heavy metals from highly active to poorly active fractions. The immobilization treatment significantly decreased the Cd and Pb content in corn grains. Under the biochar 22.5 t·hm-2 treatment, the maximum Cd content decreased by 85%, and the content of Cd in grains met the National Food Safety Standard value (GB 2762-2012, Cd ≤ 0.1 mg·kg-1). Under the lime 4.5 t·hm-2 treatment, the maximum Pb content decreased by 59.6%, but did not meet the National Food Safety Standard value (GB 2762-2012, Pb ≤ 0.2 mg·kg-1). The yield increased after some of the amendment treatments. The yield increased by 29.1% after the humic acid 22.5 t·hm-2 treatment. Based on a comprehensive analysis of the effects of different amendments and their application amounts on the yield, heavy metal mobility in soil, and contents in crops, sepiolite and lime are the best choice of amendments for the remediation of Cd and Pb-contaminated cultivated soil around a lead-zinc mine area. The application amounts are sepiolite 45 t·hm-2 and lime 2.25 t·hm-2, respectively. |
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