Arsenic Dynamics in Porewater of an Intermittently Irrigated Paddy Field in Bangladesh

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• 作者：Linda C. Roberts ; Stephan J. Hug ; Andreas Voegelin ; Jessica Dittmar ; Ruben Kretzschmar ; Bernhard Wehrli ; Ganesh C. Saha ; A. Borhan M. Badruzzaman ; M. Ashraf Ali
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：February 1, 2011
• 年：2011
• 卷：45
• 期：3
• 页码：971-976
• 全文大小：343K
• 年卷期：v.45,no.3(February 1, 2011)
• ISSN：1520-5851

文摘

In Bangladesh, irrigation of dry season rice (boro) with arsenic-contaminated groundwater is leading to increased As levels in soils and rice, and to concerns about As-induced yield reduction. Arsenic concentrations and speciation in soil porewater are strongly influenced by redox conditions, and thus by water management during rice growth. We studied the dynamics of As, Fe, P, Si, and other elements in porewater of a paddy field near Sreenagar (Munshiganj), irrigated according to local practice, in which flooding was intermittent. During early rice growth, As porewater concentrations reached up to 500 渭g L^鈭? and were dominated by As^III, but As release was constrained to the lower portion of the soil above the plow pan. In the later part of the season, soil conditions were oxic throughout the depth range relevant to rice roots and porewater concentrations only intermittently increased to 150 渭g L^鈭? As^V following irrigation events. Our findings suggest that intermittent irrigation, currently advocated in Bangladesh for water-saving purposes, may be a promising means of reducing As input to paddy soils and rice plant exposure to As.