Jingtao Wu1, Qingqiu Zhou2, Rong Huang1, Kejun Wu3, Zhian Li4. 1. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China. 2. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology, Yunnan University, Kunming 650500, PR China. 3. Tourism Development Research Center of Sichuan, School of Tourism, Leshan Normal University, Leshan 614000, PR China; Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China. Electronic address: wkj966516@lsnu.edu.cn. 4. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China. Electronic address: lizan@scbg.ac.cn.
Abstract
Heavy metal mobilisation or immobilisation have been widely applied in situ for soil remediation. However, the consequences of the mobilisation or immobilisation amendments on soil health and heavy metal transfer are rarely compared. In this study, four mobilisation additives (EDTA, humic acid, oxalic acid and citric acid) and four immobilisation additives (calcium silicate, lime, biochar and pig manure) were applied in soils contaminated with Cd, Zn, and Pb to investigate their effects on soil microbial and nematode communities, chemical speciation of metals in Amaranthus tricolour L., and metal food chain transfer in soil-plant-insect system. We found that mobilisation amendments inhibited plant growth and EDTA reduced microbial biomass indicated by phospholipid fatty acids. In contrast, immobilisation amendments promoted plant growth. However, abundances of microbe and nematode were reduced by calcium silicate and lime, while they were substantially increased by biochar and pig manure. We also realised that the immobilisation amendments shifted the water-soluble and pectate-/protein-associated fractions to phosphate-/oxalate-associated fractions of metals in plant leaves, enhanced detoxification ability of Prodenia litura larvae, and reduced metal transfer along food chain. However, opposite changes were observed in mobilisation treatments. According to redundancy analysis, we found that the addition of biochar or pig manure improved soil health and function by reducing metal availability and increasing soil available N and P concentrations. Our results indicate that organic immobilisation amendments most effectively improve soil health and reduce metal transfer, and should be recommended for remediation of heavy metal-contaminated soils.
Heavy n class="Chemical">metal mobilisationpan> or immobilisationpan> have beenpan> widely applied inpan> situ for soil remediationpan>. However, the conpan>sequenpan>ces of the mobilisationpan> or immobilisationpan> amenpan>dmenpan>ts onpan> soil health and heavy n class="Chemical">metal transfer are rarely compared. In this study, four mobilisation additives (EDTA, humic acid, oxalic acid and citric acid) and four immobilisation additives (calcium silicate, lime, biochar and pig manure) were applied in soils contaminated with Cd, Zn, and Pb to investigate their effects on soil microbial and nematode communities, chemical speciation of metals in Amaranthus tricolour L., and metal food chain transfer in soil-plant-insect system. We found that mobilisation amendments inhibited plant growth and EDTA reduced microbial biomass indicated by phospholipid fatty acids. In contrast, immobilisation amendments promoted plant growth. However, abundances of microbe and nematode were reduced by calcium silicate and lime, while they were substantially increased by biochar and pig manure. We also realised that the immobilisation amendments shifted the water-soluble and pectate-/protein-associated fractions to phosphate-/oxalate-associated fractions of metals in plant leaves, enhanced detoxification ability of Prodenia litura larvae, and reduced metal transfer along food chain. However, opposite changes were observed in mobilisation treatments. According to redundancy analysis, we found that the addition of biochar or pig manure improved soil health and function by reducing metal availability and increasing soil available N and P concentrations. Our results indicate that organic immobilisation amendments most effectively improve soil health and reduce metal transfer, and should be recommended for remediation of heavy metal-contaminated soils.
Authors: Yajun Chang; Zheyuan Feng; Jixiang Liu; Junfang Sun; Linhe Sun; Qiang Tang; Dongrui Yao Journal: Int J Environ Res Public Health Date: 2022-01-29 Impact factor: 3.390