Contrasting impacts of mobilisation and immobilisation amendments on soil health and heavy metal transfer to food chain

• Published in: Ecotoxicology and environmental safety Vol. 209; p. 111836
• Main Authors: Wu, Jingtao, Zhou, Qingqiu, Huang, Rong, Wu, Kejun, Li, Zhian
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.02.2021; Elsevier
• Subjects: Amaranthus tricolour; Animals; Biomass; Calcium Compounds; Charcoal; Chemical forms; Environmental Pollution - analysis; Environmental Restoration and Remediation; Food Chain; Manure; Metals, Heavy - analysis; Nematode; Oxides; Phosphates - analysis; Phospholipid fatty acids; Plants; Prodenia litura; Silicates; Soil; Soil Pollutants - analysis; Swine; Nematode; Prodenia litura; Chemical forms; Phospholipid fatty acids; Amaranthus tricolour
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2020.111836

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. [Display omitted] •The changes in soil microbial and nematode communities were nutrient-driven.•Metal transfer along food chain was associated with their chemical forms in plant.•Biochar and pig manure improved soil health and reduced metal transfer.