Guan Di, Ji Xionghui, Liu Saihua, Chen Shan, Xie Yunhe, Wu Jiamei
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.
Heliyon. 2024 Dec 5;10(24):e40910. doi: 10.1016/j.heliyon.2024.e40910. eCollection 2024 Dec 30.
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 NHOAc, CaCl-DTPA, 0.01 mol/L CaCl, 0.1 mol/L CaCl, 0.5 mol/L NaHPO, 0.05 mol/L NaHCO, 0.1 mol/L NaNO, 0.1 mol/L HNO), 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, CaCl, HNO, and CaCl-DTPA solutions exhibited high extraction efficiency for Cd (42.2-88.4 %); for As, NaHPO, HCl, and HNO have the extraction efficiency (0.85-23.4 %). The concentration of Cd extracted by 0.01 mol/L CaCl was significantly positively correlated with Cd levels in rice. The potential risk extraction threshold of CaCl 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 CaCl-DTPA and 0.05 mol/L NaHCO 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 CaCl, CaCl-DTPA, and 0.05 mol/L NaHCO 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.
稻田土壤中镉（Cd）和砷（As）的污染风险已引起全球关注。为科学、客观地评价土壤Cd、As的生物有效性以及污染农田中Cd或As阈值的风险，本研究对不同类型的萃取剂提取Cd和As的潜在效率进行了研究。以中国南方典型双季稻产区湖南岳阳和益阳两种不同母质的土壤作为供试土壤。比较了10种萃取剂（超纯水、0.1 mol/L HCl、1.0 mol/L NHOAc、CaCl-DTPA、0.01 mol/L CaCl、0.1 mol/L CaCl、0.5 mol/L NaHPO、0.05 mol/L NaHCO、0.1 mol/L NaNO、0.1 mol/L HNO）对土壤有效Cd和As的萃取能力。同时，在收获期监测水稻植株和籽粒中Cd和As的含量，并分析萃取态与水稻中Cd、As含量的相关性。结果表明，HCl、CaCl、HNO和CaCl-DTPA溶液对Cd的萃取效率较高（42.2-88.4%）；对于As，NaHPO、HCl和HNO的萃取效率较高（0.85-23.4%）。0.01 mol/L CaCl萃取的Cd浓度与水稻中的Cd含量显著正相关。砂壤土中CaCl的潜在风险萃取阈值为0.178 mg/kg，而黏土中为0.312 mg/kg。黏土中CaCl-DTPA和0.05 mol/L NaHCO萃取的As浓度与水稻中的As含量显著正相关，潜在风险萃取阈值分别为0.115 mol/L和0.106 mg/kg。这些研究表明，0.01 mol/L CaCl、CaCl-DTPA和0.05 mol/L NaHCO的重金属萃取方法能够反映农田中Cd和As的污染程度，并表明它们有潜力作为评估砂壤土和黏土稻田中Cd和As污染风险的方法。
