Nano zerovalent Fe did not reduce metal(loid) leaching and ecotoxicity further than conventional Fe grit in contrasting smelter impacted soils: A 1-year field study.

Lewandowská, Šárka; Vaňková, Zuzana; Beesley, Luke; Cajthaml, Tomáš; Wickramasinghe, Niluka; Vojar, Jiří; Vítková, Martina; Tsang, Daniel C W; Ndungu, Kuria; Komárek, Michael

Abstract

The majority of the studies on nanoscale zero-valent iron (nZVI) are conducted at a laboratory-scale, while field-scale evidence is scarce. The objective of this study was to compare the metal(loid) immobilization efficiency of selected Fe-based materials under field conditions for a period of one year. Two contrasting metal(loid) (As, Cd, Pb, Zn) enriched soils from a smelter-contaminated area were amended with sulfidized nZVI (S-nZVI) solely or combined with thermally stabilized sewage sludge and compared to amendment with microscale iron grit. In the soil with higher pH (7.5) and organic matter content (TOC = 12.7 %), the application of amendments resulted in a moderate increase in pH and reduced As, Cd, Pb, and Zn leaching after 1-year, with S-nZVI and sludge combined being the most efficient, followed by iron grit and S-nZVI alone. However, the amendments had adverse impacts on microbial biomass quantity, S-nZVI being the least damaging. In the soil with a lower pH (6.0) and organic matter content (TOC = 2.3 %), the results were mixed; 0.01 M CaCl extraction data showed only S-nZVI with sludge as remaining effective in reducing extractable concentrations of metals; on the other hand, Cd and Zn concentrations were increased in the extracted soil pore water solutions, in contrast to the two conventional amendments. Despite that, S-nZVI with sludge enhanced the quantity of microbial biomass in this soil. Additional earthworm avoidance data indicated that they generally avoided soil treated with all Fe-based materials, but the presence of sludge impacted their preferences somewhat. In summary, no significant differences between S-nZVI and iron grit were observed for metal(loid) immobilization, though sludge significantly improved the performance of S-nZVI in terms of soil health indicators. Therefore, this study indicates that S-nZVI amendment of soils alone should be avoided, though further field evidence from a broader range of soils is now required. [Abstract copyright: Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.]

• Journal Article Type: Article
• Acceptance Date: Mar 20, 2024
• Online Publication Date: Mar 26, 2024
• Deposit Date: Apr 23, 2024
• Publicly Available Date: Apr 23, 2024
• Journal: The Science of the total environment
• Print ISSN: 0048-9697
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 927
• Pages: 171892
• DOI: https://doi.org/10.1016/j.scitotenv.2024.171892
• Keywords: Metal(loid) immobilization, Sewage sludge, Soil remediation, Sulfidized nZVI, Soil pore water