• 关键词：砷  SEPs  形态分级  湖南  石灰性土壤

• 基金项目：国家杰出青年科学基金项目(No.40325003)

• 武斌
• 1. 中国科学院地理科学与资源研究所环境修复中心, 北京 100101; 2. 中国科学院研究生院, 北京 100049

• 廖晓勇
• 中国科学院地理科学与资源研究所环境修复中心, 北京 100101

• 陈同斌
• 中国科学院地理科学与资源研究所环境修复中心, 北京 100101

• 阎秀兰
• 1. 中国科学院地理科学与资源研究所环境修复中心, 北京 100101; 2. 中国科学院研究生院, 北京 100049

• 摘要：通过对修改自Chang和Jackson及Manful的5种SEPs方法进行对比研究,确定适合于石灰性土壤砷分级的SEPs方法,即1mol·L^-1NH₄Cl、0.5mol·L^-1NH₄F、0.1mol·L^-1NaOH、0.5mol·L^-1H₂SO₄分别提取松散结合态、Al-结合态、Fe-结合态和Ca-结合态的As,以HNO₃-H₂O₂消煮法测定残渣态As含量.同时发现,前人常采用的“可还原态”提取步骤不适合用于石灰性土壤的砷分级.该分级方法的确立对于石灰性土壤砷污染的风险评价具有一定科学意义和实用价值.

• Abstract：Arsenic (As) fractionation is an important indicator for assessing its risk and bioavailability in soil. The sequential extraction procedure (SEP) is a commonly utilized fractionation method for assessing soil As distributions. Various SEP procedures are compared (modified from the original methods developed by Chang and Jackson (1957) and SEP method by Manful (1992)), and identifies the most reliable SEP for assessing specific calcareous paddy field soils contaminated by As. The final strategy includes the following five extraction steps: (1) 1mol·L^-1 NH₄ Cl, 20℃/0.5h; (2) 0.5 mol·L^-1 NH₄ F 20℃/1h; (3) 0.1mol·L^-1 NaOH 20℃/17h; (4) 0.5mol·L^-1 H₂SO₄ 20℃/1h and (5) HNO₃ /H₂O₂ digestion. These As fractions are: (1) non-specifically absorbed (2) bound to aluminum (3) bound to iron (4) bound to calcium and (5) in residual phases. Moreover, the research indicates that the “reducible phases” extracted with dithionite-citrate-bicarbonate (DCB) are not suitable for specific calcareous paddy field soils. It is conclude that the establishment of the As fractionation procedure is important and practical for assessing the risk of As-contaminated calcareous soil.

• Key words：arsenic  SEPs  fractionation  Hunan Provence  calcareous soil

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