Unidad de Espectroscopía, División de Química, Departamento de Tecnología, CIEMAT, Madrid, Spain.
Sci Total Environ. 2012 Jan 1;414:600-7. doi: 10.1016/j.scitotenv.2011.09.051. Epub 2011 Dec 10.
Arsenic accumulation and speciation in different plant species growing in two polluted sites were examined, in addition to arsenic transfer from soils to plants. The studied areas were two abandoned mercury mines in Northern Spain, La Soterraña and Los Rueldos. Plants accumulated extremely high amounts of arsenic in their tissues. Accumulation rates depend on both the grade of pollution of the site and on the plant species itself. Total arsenic concentrations varied depending on the part of the plant, with roots accumulating the most arsenic in all the studied plants (up to 1400 mg · kg(-1)). A suitable extraction method for arsenic speciation in the studied samples was developed and optimized using 0.3M orthophosphoric acid as the extracting agent in a graphite block digestion system at 90 °C for 1h. Extraction efficiencies were above 80% and speciation was not altered, since recoveries of the spiked arsenic species (As(III), As(V), DMA (dimethylarsonic acid) and MMA (monomethylarsonic acid)) were between 94 and 102%. Speciation studies were performed on the parts of each plant species by means of HPLC-ICP-MS with the results indicating no significant differences in the speciation between parts of the plants. As(V) was always the predominant species, although a non-negligible amount of As(III) was found for all samples. Little amounts of MMA and DMA occurred in certain samples. Arsenic uptake by plants depends on the plant available arsenic fraction in soils, here considered as the sum of water-soluble and phosphate-extractable fractions. Although soils from La Soterraña were less polluted, arsenic bioavailability was much higher than in Los Rueldos. Soil-to-plant transfer factors, based on total and available arsenic in soils, were evaluated for the studied plants. Dryopteris filix-mas and Calluna vulgaris (L.) Hull, from La Soterraña and Los Rueldos respectively, were the plants with the highest abilities to extract arsenic from their corresponding soils.
研究了在西班牙北部两个受污染地区生长的不同植物物种中的砷积累和形态，以及砷从土壤向植物的转移。研究区域是西班牙北部的两个废弃汞矿，即拉索泰拉纳和洛斯鲁埃尔多斯。植物在其组织中积累了极高水平的砷。积累率取决于污染程度和植物种类本身。总砷浓度取决于植物的部位，所有研究植物的根部积累的砷最多（高达 1400mg·kg(-1)）。开发并优化了一种适用于研究样品中砷形态分析的提取方法，使用 0.3M 正磷酸作为提取剂，在石墨块消解系统中于 90°C 下提取 1 小时。提取效率超过 80%，形态没有改变，因为添加的砷形态（As(III)、As(V)、DMA（二甲基砷酸）和 MMA（一甲基砷酸））的回收率在 94%至 102%之间。通过 HPLC-ICP-MS 对每个植物物种的不同部位进行了形态分析，结果表明植物不同部位的形态没有显著差异。As(V)始终是主要形态，尽管所有样品中都发现了不可忽视的 As(III)量。某些样品中还存在少量的 MMA 和 DMA。植物对砷的吸收取决于土壤中植物可利用的砷分数，这里认为是水溶性和磷酸盐可提取分数的总和。尽管拉索泰拉纳的土壤污染程度较低，但砷的生物可利用性远高于洛斯鲁埃尔多斯。基于土壤中总砷和可利用砷，评估了研究植物的土壤-植物转移因子。来自拉索泰拉纳和洛斯鲁埃尔多斯的鳞毛蕨和普通石楠，是从各自土壤中提取砷能力最高的植物。
