Schmidt Anne-Christine, Kutschera Kristin, Mattusch Jürgen, Otto Matthias
Faculty of Chemistry and Physics, TU Bergakademie Freiberg, Institute of Analytical Chemistry, Freiberg, Germany.
Chemosphere. 2008 Dec;73(11):1781-7. doi: 10.1016/j.chemosphere.2008.09.001. Epub 2008 Oct 10.
Phenylated arsenic compounds occur as highly toxic contaminants in former military areas where they were formed as degradation products of chemical warfare agents. Some phenylarsenic compounds such as roxarsone and aminophenylarsonic acids were applied as food additive and veterinary drugs in stock-breeding and therefore pose an environmental risk in agricultural used sites. Very few data exist in the literature concerning uptake and effects of phenylarsenic compounds in plants growing on contaminated soils. In this study, the accumulation, extractability, and metabolization of five different phenylarsenic compounds, phenylarsonic acid, p- and o-aminophenylarsonic acid, phenylarsine oxide, and 3-nitro-4-hydroxyphenylarsonic acid called roxarsone, by the terrestrial plant Tropaeolum majus were investigated. Ion chromatography coupled to inductively coupled plasma mass spectrometry was used to differentiate these arsenic compounds, and inductively coupled plasma atomic emission spectroscopy was used for total arsenic quantification. All compounds considered were taken up by the roots and transferred to stalks, leaves, and flowers. The strongest accumulation was observed for unsubstituted phenylarsonic acid followed by its trivalent analogue phenylarsine oxide that was mostly oxidized in soil whereas the amino- or nitro- and hydroxy-substituted phenylarsonic acids were accumulated to a smaller degree. The highest extraction yield of 90% for ground leaf material was achieved by 0.1M phosphate buffer, pH 7.7, in a two-step extraction with a total extraction time of 24h. The extraction of higher amounts of arsenic (50-70% of total arsenic present in leaves depending on arsenic species application) from non-ground intact leaves with deionized water in comparison with the buffer (20-40% of total arsenic) is ascribed to osmotic effects. The arsenic species analysis revealed a cleavage of the amino groups from the phenyl ring for plants treated with aminophenylarsonic acids. A further important metabolic effect consisted in the production of inorganic arsenate and arsenite from the phenylated arsonic acid groups.
苯基化砷化合物作为剧毒污染物存在于 former military areas，它们是化学战剂的降解产物。一些苯基砷化合物，如洛克沙胂和氨基苯基胂酸，曾被用作食品添加剂和兽药用于畜牧业，因此在农业使用场所构成环境风险。关于苯基砷化合物在受污染土壤中生长的植物中的吸收和影响，文献中存在的数据非常少。在本研究中，研究了陆生植物旱金莲对五种不同苯基砷化合物，即苯基胂酸、对氨基苯基胂酸和邻氨基苯基胂酸、氧化苯胂和 3-硝基-4-羟基苯基胂酸（称为洛克沙胂）的积累、可提取性和代谢情况。采用离子色谱-电感耦合等离子体质谱联用技术区分这些砷化合物，并用电感耦合等离子体原子发射光谱法进行总砷定量。所有考虑的化合物都被根部吸收并转移到茎、叶和花中。未取代的苯基胂酸积累最强，其次是其三价类似物氧化苯胂，氧化苯胂在土壤中大多被氧化，而氨基或硝基和羟基取代的苯基胂酸积累程度较小。通过 0.1M pH 7.7 的磷酸盐缓冲液在两步提取中，总提取时间为 24 小时，对磨碎的叶片材料实现了 90%的最高提取率。与缓冲液（占叶片中总砷的 20-40%）相比，用去离子水从完整未磨碎的叶片中提取出更高量的砷（取决于砷物种的施用情况，占叶片中总砷的 50-70%）归因于渗透作用。砷物种分析表明，用氨基苯基胂酸处理的植物中，氨基从苯环上断裂。另一个重要的代谢作用是从苯基化胂酸基团产生无机砷酸盐和亚砷酸盐。
