高砷煤矿污染稻田水稻对砷的吸收与赋存特征研究

Study on the Uptake and Occurrence Features of Arsenic in Rice in the Field Contaminated by High Arsenic Coal Mine

为研究砷污染稻田水稻(Oryza sativa L.)各器官(根、茎、叶、稻壳、稻米)在拔节期、灌浆期、成熟期对不同形态砷的富集、吸收、转运和分布特征,以贵州省兴仁县高砷煤矿区砷污染稻田的水稻为研究对象,采用高效液相色谱-氢化物发生-原子荧光光谱法测定水稻各生育时期各器官中形态砷含量。研究表明,随着水稻生长,根部对As的富集逐渐降低,而水稻茎、叶部对As富集并未随根部As含量降低而降低;拔节期至灌浆期是茎、叶部对As富集的主要生长期。不同生育时期水稻根部主要富集As(Ⅴ),但水稻向茎部主要输送As(Ⅲ),在成熟期茎、叶部和稻米中As(Ⅲ)占总砷含量的70%以上。拔节期根部阻留As能力和茎部向叶部输送分配As的能力都相对较强,但随着水稻生长而逐渐减弱。水稻成熟期茎部与叶部相比,可能更易赋存As(Ⅴ)。成熟期水稻各部位As(Ⅲ)含量比值为根?茎?叶?稻壳?稻米=91.6?20.5?6.3?1.6?1;As(Ⅴ)含量比值为根?茎?叶?稻壳?稻米=620.8?12.2?5.7?4.7?1。水稻各器官吸收不同形态砷的同时,会保持体内As(Ⅲ)与As(Ⅴ)的平衡。研究结果可为深入认识矿业背景条件下砷在水稻中的富集及形态分布提供参考。

In order to study the features of enrichment of arsenic in different organs(root,stem,leaf,husk and grain)and growth periods(jointing stage,filling stage and maturing stage)of rice contaminated by the drainage of high arsenic coal mine,located in Xingren County,Guizhou Province of China,the contents of arsenic species were determined by high performance liquid chromatography-hydride-atomic fluorescence spectrometry.It was found that the content of As decreased gradually in root with the growth of rice,while it increased in stem and leaf.The As was mainly enriched from the jointing stage to the filling stage.As(V)was the main species in root during different growth periods,but more As(Ⅲ)was transported to above ground part of rice,and As(Ⅲ)accounted for more than 70%of total arsenic in the stem,leaf and grain during maturing stage.The abilities of retaining As in root and transporting As from stem to leaf at the jointing stage were relatively stronger than other stages.The accumulation of As(V)might be more susceptible in stem than in leaf during maturing stage.The ratio of As(Ⅲ)in different parts of rice at maturing stage was root.stem.leaf.husk.rice=91.6.20.6.3.1.6.1,and it was 620.8.12.2.5.7.4.7.1 for As(V).The balance of As(Ⅲ)and As(V)might be maintained in different parts of rice with the uptake of As.The results can provide a theoretical reference for further understanding the enrichment and distribution of arsenic species in rice under the mining background.