Carbonate Ions and Arsenic Dissolution by Groundwater
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- 作者：Myoung-Jin Kim ; Jerome Nriagu ; and Sheridan Haack
- 刊名：Environmental Science & Technology
- 出版年：2000
- 出版时间：August 1, 2000
- 年：2000
- 卷：34
- 期：15
- 页码：3094 - 3100
- 全文大小：107K
- 年卷期：v.34,no.15(August 1, 2000)
- ISSN：1520-5851
文摘
Samples of Marshall Sandstone, a major source ofgroundwater with elevated arsenic levels in southeastMichigan, were exposed to bicarbonate ion under controlledchemical conditions. In particular, effects of pH andredox conditions on arsenic release were evaluated. Therelease of arsenic from the aquifer rock was strongly relatedto the bicarbonate concentration in the leaching solution.The results obtained suggest that the carbonation ofarsenic sulfide minerals, including orpiment (As2S3) andrealgar (As2S2), is an important process in leaching arsenicinto groundwater under anaerobic conditions. The arseno-carbonate complexes formed, believed to be As(CO3)2-,As(CO3)(OH)2-, and AsCO3+, are stable in groundwater. Thereaction of ferrous ion with the thioarsenite fromcarbonation process can result in the formation ofarsenopyrite which is a common mineral in arsenic-richaquifers.