Arao Tomohito, Maejima Yuji, Baba Koji
National Institute for Agro-Environmental Sciences, Kannondai 3-1-3, Tsukuba, Ibaraki 305-8604, Japan.
Environ Sci Technol. 2009 Feb 15;43(4):1097-101. doi: 10.1021/es8023397.
Chemical warfare agents containing aromatic arsenicals (AAs) such as Clark I (diphenylchloroarsine) are well-known, as is the risk of leakage from such munitions into the environment. We investigated the uptake of AAs in agricultural soils by rice. Methylphenylarsinic acid (MPAA) was detected in brown rice grown in contaminated soil. Dimethylphenylarsine oxide (DMPAO) and methyldiphenylarsine oxide (MDPAO) were detected in the straw but not in the grains grown in the contaminated soil. Inthe contaminated soil, phenylarsonic acid (PAA) and MPAA concentrations decreased and DMPAO concentration increased under the flooded conditions; however, their concentrations remained unchanged underthe upland conditions. DMPAO was detected in the straw of the rice grown in PAA- or MPAA-amended soil but was not detected in that grown in a PAA- or MPAA-added solution culture. MDPAO was detected in the straw of the rice grown in diphenylarsinic acid (DPAA)-amended soil but was not detected in that grown in a DPAA-added solution culture. Thus, MPAA and DPAA were methylated not in the rice plant but in the soil under the flooded conditions. Dephenylated products were detected in the straw grown in AA-added solution cultures, but demethylated products were not detected. DMPAO and MDPAO absorbed by the shoots were retained, and MPAA and DPAA absorbed by the shoots were translocated to the grains more easily than other AAs.
含有芳香族砷化合物（AAs）的化学战剂，如克拉克一号（二苯基氯胂）广为人知，此类弹药泄漏到环境中的风险也为人所知。我们研究了水稻对农业土壤中AAs的吸收情况。在受污染土壤中种植的糙米中检测到了甲基苯胂酸（MPAA）。在受污染土壤中生长的稻草中检测到了二甲基苯胂氧化物（DMPAO）和甲基二苯基胂氧化物（MDPAO），但在谷粒中未检测到。在受污染土壤中，淹水条件下苯胂酸（PAA）和MPAA浓度降低，DMPAO浓度升高；然而，在旱地条件下它们的浓度保持不变。在添加PAA或MPAA的土壤中种植的水稻稻草中检测到了DMPAO，但在添加PAA或MPAA的溶液培养中生长的水稻稻草中未检测到。在添加二苯基胂酸（DPAA）的土壤中种植的水稻稻草中检测到了MDPAO，但在添加DPAA的溶液培养中生长的水稻稻草中未检测到。因此，MPAA和DPAA不是在水稻植株中甲基化，而是在淹水条件下的土壤中甲基化。在添加AA的溶液培养中生长的稻草中检测到了脱苯基产物，但未检测到脱甲基产物。地上部吸收的DMPAO和MDPAO被保留，地上部吸收的MPAA和DPAA比其他AAs更容易转运到谷粒中。
