Zhao Rui, Zhao Mengxia, Wang Hui, Taneike Yasuhito, Zhang Xinrong
Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084, P.R. China.
Sci Total Environ. 2006 Dec 1;371(1-3):293-303. doi: 10.1016/j.scitotenv.2006.03.019. Epub 2006 Apr 19.
Arsenic is predominantly found as an inorganic species in most terrestrial plants. However, we found that a significant proportion of organic arsenic was present in moso bamboo (Phyllostachys pubescens Mazel) shoot in a market survey of arsenic species in edible terrestrial plants. Moso bamboo shoots from different producing areas in China were collected for analysis to confirm the ubiquity of methylated arsenic species. The total arsenic concentrations of bamboo shoots were determined by hydride generation coupled atomic fluorescence spectrometry (HG-AFS), ranging from 27.7 to 94.0 microg/kg. Information about arsenic species was acquired from cold trap-hydride generation-atomic absorption spectrometry (CT-HG-AAS). Dimethylarsinic acid (DMA) was present in the amount of 13.9% to 44.9% of sum of the arsenic species in all these samples. Monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO) were also detected in certain samples in the range of 4.2-16.5% and 11.8-18.4%, respectively. In addition, bamboo shoots collected in winter were found to have more total arsenic and organic arsenic than those collected in spring. To investigate the source of the organic arsenic in moso bamboo shoots, arsenic species in the rhizosphere soils of the plants were examined. The absence of organic arsenic in soils would suggest the possibility of formation of methylated arsenic in the plants. In addition, studies of arsenic speciation in the peel and core of winter bamboo shoots showed that all the cores contained organic arsenic while no organic arsenic was detected in the peels. The study provides useful information for better understanding of the distribution of arsenic species in terrestrial plants.
在大多数陆生植物中，砷主要以无机形态存在。然而，在一项针对可食用陆生植物中砷形态的市场调查中，我们发现毛竹笋（Phyllostachys pubescens Mazel）中存在相当比例的有机砷。采集了中国不同产地的毛竹笋进行分析，以确认甲基化砷形态的普遍存在。竹笋中的总砷浓度通过氢化物发生-原子荧光光谱法（HG-AFS）测定，范围为27.7至94.0微克/千克。砷形态信息通过冷阱-氢化物发生-原子吸收光谱法（CT-HG-AAS）获取。在所有这些样品中，二甲基砷酸（DMA）占砷形态总量的13.9%至44.9%。在某些样品中还检测到一甲基砷酸（MMA）和三甲基氧化砷（TMAO），其含量分别在4.2 - 16.5%和11.8 - 18.4%范围内。此外，发现冬季采集的竹笋比春季采集的含有更多的总砷和有机砷。为了探究毛竹笋中有机砷的来源，对植物根际土壤中的砷形态进行了检测。土壤中不存在有机砷表明植物中可能形成了甲基化砷。此外，对冬笋笋皮和笋芯中砷形态的研究表明，所有笋芯都含有有机砷，而笋皮中未检测到有机砷。该研究为更好地了解陆生植物中砷形态的分布提供了有用信息。
