| Eh、pH和铁对水稻土砷释放的影响机制 |
| 摘要点击 5527 全文点击 1728 投稿时间：2016-11-30 修订日期：2016-12-29 |
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| 中文关键词 水稻土 土壤微环境 氧化还原电位 砷 pH值 铁 |
| 英文关键词 paddy soil micro-environment redox potential arsenic pH value iron |
| 作者 | 单位 | E-mail | | 钟松雄 | 环境保护部华南环境科学研究所, 广州 510655
广东工业大学环境科学与工程学院, 广州 510006 | sxzhong123@163.com | | 尹光彩 | 广东工业大学环境科学与工程学院, 广州 510006 | | | 陈志良 | 环境保护部华南环境科学研究所, 广州 510655 | chenzhiliang@scies.org | | 林亲铁 | 广东工业大学环境科学与工程学院, 广州 510006 | | | 黄润林 | 广东工业大学环境科学与工程学院, 广州 510006 | | | 刘德玲 | 广东工业大学环境科学与工程学院, 广州 510006 | | | 彭焕龙 | 环境保护部华南环境科学研究所, 广州 510655 | | | 黄玲 | 环境保护部华南环境科学研究所, 广州 510655 | | | 王欣 | 环境保护部华南环境科学研究所, 广州 510655 | | | 蒋晓璐 | 环境保护部华南环境科学研究所, 广州 510655 | |
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| 中文摘要 |
| 水稻水淹管理是导致水稻土砷大量释放和水稻对砷富集累积的关键环节.为研究土壤氧化还原电位（Eh）、pH值和铁对水稻土砷释放的影响，采用有氧/厌氧和间歇式有氧水淹培养方式，并分析土壤Eh、pH值、溶解态砷和铁（Ⅱ）随时间的变化，结果表明，长期厌氧水淹培养具有最大的砷释放量，且随着土壤Eh降低，砷（Ⅲ）和总砷（Ⅴ）的浓度均显著提高，其中相比于第一阶段，第二阶段砷（Ⅲ）和砷（Ⅴ）浓度分别提高了1.37 μg·L-1和0.99 μg·L-1；相反，间歇式有氧水淹处理砷的释放量则相对较低，当有氧处理时间最长（6 d）时，砷的释放量最低.土壤Eh与pH值和砷的关系研究表明，二者均与土壤溶液砷呈指数关系，且随着土壤Eh降低和pH提高，水稻土砷的释放速率增大；土壤溶液铁（Ⅱ）与砷则存在显著正相关关系（r=0.868，P<0.001）.水稻土微环境中Eh降低和pH值提升是驱动砷释放的关键因素，因而有氧水管理模式是能够抑制砷的释放和降低水稻对砷吸收累积的有效方法. |
| 英文摘要 |
| The massive release of soil arsenic and its enrichment in rice are significantly associated with the flooded and anaerobic management in paddy soil. Soil redox potential (Eh), pH and iron oxides exert remarkable impacts on arsenic release, which remain to be explored. In this study, long-term aerobic and anaerobic as well as intermittent aerobic incubation treatments were applied to investigate the influences of Eh, pH and iron content on arsenic release. It was found that anaerobic and flooded treatment contributed to the highest arsenic release. With decreasing Eh, significant enhancement in As(Ⅲ) and As(Ⅴ) contents in soil solution was observed. Particularly, As(Ⅲ) and As(Ⅴ) contents during the second phase increased by 1.37 and 0.99 μg·L-1compared with those in the first phase. Conversely, significant reduction in soil arsenic release (P<0.05) occurred when intermittent aerobic treatment was adopted, and the lowest level of arsenic release was observed along with the longest treatment time (6 d). The exponent relationships between arsenic and soil Eh, pH and Fe2+ content were also established, which indicated that arsenic release could be accelerated by lower pH and elevated Eh. In addition, a significant positive correlation was also found between iron(Ⅱ) content and arsenic content in soil solution. Since low Eh and elevated pH served as critical factors driving arsenic release, intermittent and aerobic water management was proved to be an effective method for the inhibition of arsenic release and uptake and accumulation of arsenic by rice. |
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