Dipartimento di Chimica e Farmacia, Università Degli Studi di Sassari, Via Vienna, 2, I-07100, Sassari, Italy.
Dipartimento di Agraria, Università Degli Studi di Sassari, Viale Italia, 39A, I-07100, Sassari, Italy.
J Environ Manage. 2022 Jan 15;302(Pt B):114105. doi: 10.1016/j.jenvman.2021.114105. Epub 2021 Nov 18.
Food is the major route of arsenic (As) intake for humans, and rice is the staple food for more than half of the world's population. Unfortunately, rice bioaccumulates large amounts of As from the paddy field, and the toxicity of this element in the kernel is closely linked to its chemical form. Therefore, it is of the utmost importance to have access to an integrated set of analytical methods, capable of measuring the concentration of As in its various chemical forms in soil and rice. Hence, the principal aim of this study was to assess and validate a group of inductively coupled plasma - mass spectrometry (ICP-MS) and IC-ICP-MS (IC, Ionic Chromatography) methods designed to measure the amount of the total or extracted As and its main chemical species (As(III), As(V), monomethylarsonic acid, MMA, and dimethylarsinic acid, DMA) in flours of rice grain and in soils. Great attention has been given to the assessment and the optimization of extraction methods of As species from these matrices. No appreciable interconversion among As species has been observed using an aqueous solution 1 mol dm of phosphoric acid and 0.5 mol dm of L (+)-ascorbic acid for the extraction from soils, and an aqueous solution 0.2% (w/v) of nitric acid for the extraction from rice flour. Validation has been successfully accomplished in terms of limit of detection, limit of quantification, linearity and accuracy. In addition to many certified reference materials, these methods have been tested on real samples of soils and rice grains of the Aleramo genotype obtained through traditional or intermittent irrigation methods. Data obtained revealed the critical role of the intermittent irrigation methods in determining the nature and the amount of the As chemical species in rice grains as well as in soils. As(V) is the only species found in soil irrigated by sprinkling, while the most toxic As(III) dominates in soil irrigated by continuous flooding. On the other hand, the most abundant species found in continuously flooded Aleramo rice grains are As(III) and - mostly - DMA, whereas As(V), less toxic than As(III), represents 60% of the total inorganic compounds measured in sprinkler-irrigated rice. Lastly, the total amount of As measured in this rice is 3.8% of that measured in rice irrigated by continuous flooding.
食物是人类摄入砷（As）的主要途径，而大米是世界上一半以上人口的主食。不幸的是，大米从稻田中大量吸收砷，其内核中元素的毒性与其化学形态密切相关。因此，获得一套能够测量土壤和大米中各种化学形态砷浓度的综合分析方法至关重要。因此，本研究的主要目的是评估和验证一组电感耦合等离子体质谱（ICP-MS）和 IC-ICP-MS（IC，离子色谱法）方法，这些方法旨在测量稻谷粉和土壤中总砷或提取砷及其主要化学物质（As(III)、As(V)、一甲基砷酸、MMA 和二甲基砷酸、DMA）的含量。研究人员非常关注从这些基质中提取砷形态的方法的评估和优化。在使用 1 摩尔磷酸和 0.5 摩尔 L(+)-抗坏血酸的水溶液从土壤中提取以及使用 0.2%（w/v）硝酸的水溶液从大米粉中提取时，没有观察到砷形态之间的明显转化。在检出限、定量限、线性和准确度方面已经成功地完成了验证。除了许多经过认证的参考材料外，这些方法还在通过传统或间歇灌溉方法获得的 Aleramo 基因型的土壤和大米实际样本上进行了测试。获得的数据表明，间歇灌溉方法在确定大米和土壤中砷化学物质的性质和数量方面起着关键作用。As(V)是通过喷洒灌溉的土壤中唯一存在的物种，而在连续淹没灌溉的土壤中则以最毒的 As(III)为主。另一方面，在连续淹没灌溉的 Aleramo 大米中含量最丰富的物种是 As(III)和——主要是——DMA，而毒性低于 As(III)的 As(V)则代表在喷洒灌溉大米中测量的总无机化合物的 60%。最后，在这种大米中测量的总砷量是在连续淹没灌溉大米中测量的砷量的 3.8%。
