| 基于DGT技术的广西碳酸盐岩区稻米镉含量主控因素 |
| 摘要点击 2048 全文点击 609 投稿时间：2021-05-14 修订日期：2021-06-22 |
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| 中文关键词 镉积累 地质高背景土壤 生物有效性 影响因素 拟合模型 梯度扩散薄膜技术(DGT) |
| 英文关键词 cadmium accumulation soil with high geological background bioavailability influence factors fitting model diffusive gradients in thin films technology(DGT) |
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| 中文摘要 |
| 为探究广西碳酸盐岩区水稻在地质高背景下影响稻米Cd富集的主控因素，以广西西南部和北部碳酸盐岩区水稻籽粒-根系土壤样品为基础，同时结合梯度扩散薄膜技术（DGT），分析讨论了土壤pH、有机质（OM）、阳离子交换量（CEC）和DGT-Cd等与水稻籽粒ω（rice-Cd）-BCF值的关系，通过主成分分析确定主要因素并建立定量模型.结果表明，水田土壤ω（soil-Cd）均值为0.975 mg·kg-1，超标率33.33%，水稻籽粒ω（rice-Cd）均值为0.020 mg·kg-1，BCF均值为0.038，水稻籽粒Cd含量超标率为4.2%，整体呈现出水田土壤Cd含量较高但生物有效性较低的特点；研究区水稻籽粒BCF值与土壤pH和阳离子交换量在0.01水平下显著负相关，与DGT-Cd在0.01水平下显著正相关，与有机质在0.05水平下显著负相关；主成分分析结果显示，土壤Cd全量、pH和DGT-Cd是影响广西碳酸盐岩区水稻富集Cd的主要因素；以土壤Cd全量、pH和DGT-Cd为变量建立广西碳酸盐岩区水稻籽粒BCF值拟合方程，模型决定系数为0.717，有较好的预测效果. |
| 英文摘要 |
| In order to explore the main controlling factors of Cd enrichment in rice under a geological high background in the Guangxi carbonate rock area, this study was based on rice grain-root soil samples from the carbonate rock areas in the southwest and north of Guangxi. Combined with diffusive gradients in thin films technology (DGT), the relationship between soil pH, organic matter, cation exchange capacity (CEC), DGT-Cd, and ω(rice-Cd)-BCF value in rice grains was analyzed and discussed. The main factors were determined by principal component analysis, and a quantitative model was established. The results showed that the average value of ω(soil-Cd) was 0.975 mg·kg-1, and the over-standard rate was 33.33%; the average value of ω(rice-Cd) was 0.020 mg·kg-1, and the average BCF value was 0.038, and the over-standard rate of Cd content in rice grains was 4.2%. The content of Cd in paddy soil was high, but bioavailability was low in the study area. The BCF value of rice grains in the study area was significantly negatively correlated with soil pH and cation exchange capacity at the level of 0.01, positively correlated with DGT-CD at the level of 0.01, and negatively correlated with organic matter at the level of 0.05. The results of principal component analysis showed that the total amount of Cd in the soil, pH, and DGT-Cd were the main factors affecting the accumulation of Cd in rice in the Guangxi carbonate rock area. Taking the total amount of Cd in the soil, pH, and DGT-Cd as variables, the fitting equation of BCF value of rice grains in the Guangxi carbonate rock region was established, and the determination coefficient of the model was 0.717, which could better predict the content of Cd in rice grains in this region. |
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