Arsenic Bioavailability to Rice Is Elevated in Bangladeshi Paddy Soils
Arsenic Bioavailability to Rice Is Elevated in Bangladeshi Paddy Soils
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DOI：
10.1021/es101952f
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发表时间：
2010-11-15
影响因子：
11.4
通讯作者：
Zhao, Fang-Jie
中科院分区：
文献类型：
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作者：
Khan, M. Asaduzzaman;Stroud, Jacqueline L.;Zhao, Fang-Jie
孟加拉三角洲的一些水稻土由于灌溉富含砷的地下水而受到砷的污染，这可能会导致产量损失并增加砷向食物链的转移。盆栽试验研究了这些土壤是否比其他含As或受采矿活动污染的土壤具有更高的As生物有效性。采集了14种不同来源和不同As污染程度(4-138 mg As kg(-1))的土壤，其中10种来自孟加拉国水田(受灌溉水污染)，2种来自中国和英国(受地源或采矿影响)。与其他土壤相比，孟加拉土壤可被磷酸铵萃取的总砷的百分比更高(特别是吸附的砷)，而且在洪水发生时，也有更多的砷释放到孔隙水中。在孟加拉土壤中，土壤As浓度随着土壤As浓度的增加而增加，其中亚砷酸盐是主要的As物种。在含~gt；13 mg/kg(-1)的孟加拉土壤中，水稻生长和产量显著降低，而在其他土壤中则不显著。磷酸盐可提取态或孔隙水态砷比全土壤态砷更能反映土壤的生物有效性。稻草As浓度随着土壤As浓度的增加而增加；然而，由于植物毒性似乎导致了较低的籽粒As浓度。水稻籽粒中无机砷和二甲基砷酸(DMA)的相对比例因土壤不同而不同，温室植株中DMA的比例大于同一土壤和同一水稻品种稻田的籽粒样品，表明环境对水稻籽粒中As的存在有较强的影响。这项研究表明，受灌溉污染的孟加拉水稻土具有比其他土壤更高的As生物有效性，导致As对水稻的植物毒性和大量的产量损失。
Some paddy soils in the Bengal delta are contaminated with arsenic (As) due to irrigation of As-laden groundwater, which may lead to yield losses and elevated As transfer to the food chain. Whether these soils have a higher As bioavailability than other soils containing either geogenic As or contaminated by mining activities was investigated in a pot experiment Fourteen soils varying in the source and the degree (4-138 mg As kg(-1)) of As contamination were collected, 10 from Bangladeshi paddy fields (contaminated by irrigation water) and two each from China and the UK (geogenic or mining impacted), for comparison. Bangladeshi soils had higher percentages of the total As extractable by ammonium phosphate (specifically sorbed As) than other soils and also released more As into the porewater upon flooding. Porewater As concentrations increased with increasing soil As concentrations more steeply in Bangladeshi soils, with arsenite being the dominant As species. Rice growth and grain yield decreased markedly in Bangladeshi soils containing >13 mg As kg(-1), but not in the other soils. Phosphate-extractable or porewater As was a better indicator of As bioavailability than total soil As. Rice straw As concentrations increased with increasing soil As concentrations; however, As phytotoxicity appeared to result in lower grain As concentrations. The relative proportions of inorganic As and dimethylarsinic acid (DMA) in grain varied among soils, and the percentage DMA was larger in greenhouse-grown plants than grain samples collected from the paddy fields of the same soil and the same rice cultivar, indicating a strong environmental influence on As species found in rice grain. This study shows that Bangladeshi paddy soils contaminated by irrigation had a higher As bioavailability than other soils, resulting in As phytotoxicity in rice and substantial yield losses.