Impact of soil treatment with Nitrilo Triacetic Acid (NTA) on Cd fractionation and microbial biomass in cultivated and uncultivated calcareous soil

• Published in: Journal of environmental health science and engineering Vol. 21; no. 2; pp. 319 - 332
• Main Authors: Mehrab, Narges, Chorom, Mostafa, Norouzi Masir, Mojtaba, Biswas, Jayanta Kumar, Fernandes de Souza, Marcella, Meers, Erik
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2023; BioMed Central Ltd; Nature Publishing Group
• Subjects: Bacterial leaching; Biological activity; Biomass; Cadmium; Calcareous soils; Calcium carbonate; Carbon content; Carbon dioxide; CD25 antigen; Chelating agents; Chelation; Corn; Cultivation; Dissolved organic carbon; Earth and Environmental Science; Environment; Environmental Economics; Environmental Engineering/Biotechnology; Environmental Health; Environmental Law/Policy/Ecojustice; Fractionation; Leaching; Loam; Microbial activity; Microbial contamination; Microorganisms; Nitrilotriacetic acid; Phytoremediation; Plant roots; Quality of Life Research; Research Article; Soil chemistry; Soil contamination; Soil investigations; Soil pollution; Soil remediation; Soil treatment; Soils; Toxicity; Waste Management/Waste Technology; Biodegradable chelators; Soil remediation; Available cadmium; Leaching; Calcium carbonate
• DOI: 10.1007/s40201-023-00857-y
• ISSN: 2052-336X

Purpose The aim of this study was to evaluate the effectiveness of nitrilotriacetic acid (NTA) on cadmium (Cd) fractions and microbial biomass in a calcareous soil spiked with Cd under cultivated ( Zea   mays L.) and uncultivated regime subject to soil leaching condition. Expanding investigations related to soil–plant interactions on metal-contaminated soils with insights on microbial activity and associated soil toxicity perspective provides novel perspectives on using metal-chelating agents for soil remediation. Methods The experimental factors were three levels of Cd contamination (0, 25, and 50 mg kg −1 soil) and three levels of NTA (0, 15, and 30 mmol L −1 ) in loamy soil under maize-cultured and non-cultured conditions. During the experiment, the adding NTA and leaching processes were performed three times. Results The results showed that the amount of leached Cd decreased in cultivated soil compared to uncultivated soil due to partial uptake of soluble Cd by plant roots and changes in Cd fractions in soil, so that Cd leached in Cd 50 NTA 30 was 9.2 and 6.1 mg L −1 , respectively, in uncultivated and cultivated soils. Also, Cd leached in Cd 25 NTA 30 was 5.7 and 3.1 mg L −1 respectively, in uncultivated and cultivated soils. The best treatment in terms of chemical and microbial characteristics of the soil with the high percentage of Cd removed from the soil was Cd 25 NTA 30 in cultivated soil. In Cd 25 NTA 30 compared to Cd 25 NTA 0 in cultivated soil, pH (0.25 unit), microbial biomass carbon (MBC, 65.0 mg kg −1 ), and soil respiration (27.5 mg C-CO 2 kg −1 24 h −1 ) decreased, while metabolic quotient (qCO 2 , 0.05) and dissolved organic carbon (DOC, 20.0 mg L −1 ) increased. Moreover, the changes of Cd fractions in Cd 25 NTA 30 in cultivated soil compared to uncultivated soil were as follows; the exchangeable Cd (F 1 , 0.27 mg kg −1 ) and Fe/Mn-oxide-bounded Cd (F 4 , 0.15 mg kg −1 ) fractions increased, in contrast, carbonate-Cd (F 2 , 2.67 mg kg −1 ) and, organically bounded Cd (F 3 , 0.06 mg kg −1 ) fractions decreased. NTA had no significant effect on the residual fraction (F 5 ). Conclusion The use of NTA, especially in calcareous soils, where most of the Cd is bound to calcium carbonate, was able to successfully convert insoluble fractions of Cd into soluble forms and increase the removal efficiency of Cd in the phytoremediation method. NTA is a non-toxic chelating agent to improve the accumulation of Cd in maize.