Effect of Combined Soil Amendment on Immobilization of Bioavailable As and Pb in Paddy Soil.

Young-Kyu Hong,Sung-Chul Kim,Sang-Phil Lee,Jae-E Yang,Jin-Wook Kim

doi:10.3390/toxics10020090

Young-Kyu Hong, Sung-Chul Kim + Show 3 more

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https://doi.org/10.3390/toxics10020090

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Journal: Toxics	Publication Date: Feb 16, 2022
Citations: 7	License type: CC BY 4.0

Affiliation: Chungnam National University, Kangwon National University

Abstract

Heavy metal pollution in soil can have detrimental effects on soil ecosystems and human health. In situ remediation techniques are widely used to reduce the bioavailable fractions of heavy metals in soil. The main objective of this study was to examine the reduction of the bioavailable fractions of As and Pb in paddy soil with artificial lightweight material (ALM) manufactured from recycled materials. A total of four treatments, including a control (no amendment), ALM10 (10% of ALM in soil), ALM10+L (10% ALM combined with 0.5% lime), and ALM10+FeO (10% ALM combined with 0.5% FeO), were applied to paddy fields, and rice (Oryza sativa L.) was cultivated after 32 weeks. The highest reduction efficiencies for the bioavailable fractions of As and Pb in soil were observed in the ALM10+FeO (52.8%) and ALM10+L treatments (65.7%), respectively. The uptake of As decreased by 52.1% when ALM10+FeO was applied to paddy soil, and that of Pb decreased by 79.7% when ALM10+L was applied. Correlation analysis between bioavailable heavy metals in soil and soil chemical properties showed that soil pH, electrical conductivity (EC), P2O5, and soil organic matter (SOM) were the main factors controlling the mobility and bioavailability of As and Pb. Overall, the efficiencies of As and Pb reduction increased synergistically in both soil and plants when FeO and lime were combined with the ALM. In future studies, long-term monitoring is necessary to examine the longevity of soil amendments.

Highlights

Heavy metal pollution in soil is a critical issue worldwide, in agricultural fields due to food safety concerns [1–4]
artificial lightweight material (ALM) produced from recycled waste, bottom ash, unburned coal, and dredged sand was examined for heavy metal remediation in soil
When ALM was applied to paddy fields, the bioavailable fractions of As and Pb decreased by 22.7% and 52.4%, respectively

Summary

Introduction

Heavy metal pollution in soil is a critical issue worldwide, in agricultural fields due to food safety concerns [1–4]. Heavy metal pollution in soil or water can be a concern because of its toxicity, persistency, bioaccumulation, and leaching into groundwater [11]. The bioavailable fraction of heavy metals differs from the total heavy metal concentration. The total heavy metal concentration can be used to determine the level of soil contamination, whereas the bioavailable fraction of heavy metals can provide information on the mobility and bioavailability of the heavy metals in soil [12–15]. Various chemical extractants have been used to estimate the bioavailable fraction of heavy metals in soil. Among the five different fractions, the exchangeable and bound to carbonate fractions are considered to be the bioavailable fractions of heavy metals [17]. Other extractant includes the toxicity characteristic leaching procedure (TCLP) for conducting ecological risk assessments, Mehlich-3, EDTA, CaCl2, and NH4NO3 [18–23]

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