Exploration of the bio-availability and the risk thresholds of cadmium and arsenic in contaminated paddy soils

Di Guan; Xionghui Ji; Saihua Liu; Shan Chen; Yunhe Xie; Jiamei Wu

Heliyon (Dec 2024)

Exploration of the bio-availability and the risk thresholds of cadmium and arsenic in contaminated paddy soils

Di Guan,
Xionghui Ji,
Saihua Liu,
Shan Chen,
Yunhe Xie,
Jiamei Wu

Affiliations

Di Guan: The Key Laboratory of Agro-Environment in Midstream of Yangtze Plain, Ministry of Agriculture, The Key Laboratory of Prevention, Control and Remediation of Soil Heavy Metal Pollution in Hunan Province, Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, 410125, PR China
Xionghui Ji: The Key Laboratory of Agro-Environment in Midstream of Yangtze Plain, Ministry of Agriculture, The Key Laboratory of Prevention, Control and Remediation of Soil Heavy Metal Pollution in Hunan Province, Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, 410125, PR China
Saihua Liu: The Key Laboratory of Agro-Environment in Midstream of Yangtze Plain, Ministry of Agriculture, The Key Laboratory of Prevention, Control and Remediation of Soil Heavy Metal Pollution in Hunan Province, Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, 410125, PR China
Shan Chen: The Key Laboratory of Agro-Environment in Midstream of Yangtze Plain, Ministry of Agriculture, The Key Laboratory of Prevention, Control and Remediation of Soil Heavy Metal Pollution in Hunan Province, Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, 410125, PR China
Yunhe Xie: The Key Laboratory of Agro-Environment in Midstream of Yangtze Plain, Ministry of Agriculture, The Key Laboratory of Prevention, Control and Remediation of Soil Heavy Metal Pollution in Hunan Province, Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, 410125, PR China
Jiamei Wu: Corresponding author.; The Key Laboratory of Agro-Environment in Midstream of Yangtze Plain, Ministry of Agriculture, The Key Laboratory of Prevention, Control and Remediation of Soil Heavy Metal Pollution in Hunan Province, Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, 410125, PR China

Journal volume & issue: Vol. 10, no. 24
p. e40910

Abstract

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Cadmium (Cd) and arsenic (As) contamination risk in paddy soils has raised global concern. In order to scientifically and objectively evaluate the bioavailability of soil Cd, As and the risk of Cd or As threshold in contaminated farmland, this study was conducted to investigate different types of extractants for their potential extraction efficiency of Cd and As. Soils from two different parent materials in Hunan, Yueyang and Yiyang, typical double-cropping rice production areas in the south of China, were used as test soils. The extraction capabilities of 10 extractants (ultrapure water, 0.1 mol/L HCl, 1.0 mol/L NH4OAc, CaCl2-DTPA, 0.01 mol/L CaCl2, 0.1 mol/L CaCl2, 0.5 mol/L NaH2PO4, 0.05 mol/L NaHCO3, 0.1 mol/L NaNO3, 0.1 mol/L HNO3), were compared for their extraction capabilities of soil available Cd and As. Meanwhile, the content of Cd and As in plants issues and grains of rice was monitored during harvest, and the Cd, As content correlation between extracted forms and rice was analyzed. The results showed that the HCl, CaCl2, HNO3, and CaCl2-DTPA solutions exhibited high extraction efficiency for Cd (42.2–88.4 %); for As, NaH2PO4, HCl, and HNO3 have the extraction efficiency (0.85–23.4 %). The concentration of Cd extracted by 0.01 mol/L CaCl2 was significantly positively correlated with Cd levels in rice. The potential risk extraction threshold of CaCl2 in sandy loam soil was 0.178 mg/kg, while it was 0.312 mg/kg in clay soil. The concentration of As extracted by CaCl2-DTPA and 0.05 mol/L NaHCO3 in clay soil was significantly positively correlated with As levels in rice, the potential risk extraction thresholds were 0.115 mol/L and 0.106 mg/kg, respectively. These investigations indicated that the heavy metals extraction methods by 0.01 mol/L CaCl2, CaCl2-DTPA, and 0.05 mol/L NaHCO3 could reflect the Cd and As pollution degree in farmland and suggest their potential to serve as methods for assessing the risk of Cd and As pollution in sandy loam and clay paddy soil.

Published in Heliyon

ISSN: 2405-8440 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Science: Science (General); Social Sciences: Social sciences (General)
Website: https://www.cell.com/heliyon/home

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