Metal Fractionation and Leaching in Soils from a Gold Mining Area in the Equatorial Rainforest Zone

Sarpong, Lilian; Boadi, Nathaniel Owusu; Akoto, Osei

doi:10.1155/2023/3542165

Cited by 2 publications

(1 citation statement)

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“…The stability of the residue fraction in terms of content before and after leaching indicates that rainwater leaching over three years had minimal impact on altering the form of Cr within the soil lattice. Sarpong et al [ 45 ] also found that compared to Cd and Mn, Cr in the soil remains predominantly in the oxidizable and residual fractions. However, the increased content of the oxidizable fraction after leaching suggests that a small portion of water-soluble CrO 4 2− transformed into a more stable oxidizable fraction.…”

Section: Discussionmentioning

confidence: 99%

The Release and Migration of Cr in the Soil under Alternating Wet–Dry Conditions

Chen,

Liang

et al. 2024

Toxics

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In recent decades, chromium contamination in soil has emerged as a serious environmental issue, demanding an exploration of chromium’s behavioral patterns in different soil conditions. This study aims to simulate the release, migration, and environmental impact of chromium (Cr) in contaminated soils under natural rainfall conditions (wet–dry cycles). Clean soils sourced from Panzhihua were used to cultivate chromium-containing soils. Simulated rainfall, prepared in the laboratory, was applied to the cultivated chromium-containing soils in indoor simulated leaching experiments. The experiments simulated three years of rainfall in Panzhihua. The results indicate that soils with higher initial Cr contents result in higher Cr concentrations in the leachate, but all soils exhibit a low cumulative Cr release. The leachate shows similar patterns in total organic carbon (TOC), pH, electrical conductivity, and Cr content changes. An analysis of the speciation of Cr in the soil after leaching reveals a significant decrease in the exchangeable fraction for each Cr species, while the residual and oxidizable Cr fractions exhibit notable increases. The wet–dry cycle has the following effects on the soil: it induces internal reduction reactions in the soil, leading to the reduction of Cr(VI) to Cr(III); it alters the binding of Cr ions to the soil, affecting the migration of chromium; and it involves microorganisms in chemical processes that consume organic matter in the soil. After three years of rainwater leaching, chromium-containing soils released a relatively low cumulative amount of total chromium, resulting in a reduced potential risk of groundwater system contamination. Most of the chromium in the chromium-containing soil is fixed within the soil, leading to less biotoxicity.

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Section: Discussionmentioning

confidence: 99%