Author(s) |
Doherty, Steven
Tighe, Matthew
Wilson, Susan C
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Publication Date |
2017
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Abstract |
Co-contamination of soils with arsenic (As) and antimony (Sb) presents unique challenges for risk management. In this study a sequence of leaching experiments evaluated zero valent iron powder, ferrihydrite, ferric chloride, aluminium and manganese oxides, and kaolinite for As and Sb immobilisation in co-contaminated soils. Iron based amendments were most effective for the reduction of As and Sb in leachate in a column leaching study. Over 48 h zero valent iron powder and ferrihydrite applied at 3% (w/ w dry weight) were most efficient, decreasing total As and Sb leachate concentrations by more than 80%. Careful moderation of pH (to > 2.5 but < ~6) with lime was required for effective co-immobilisation of both metalloids using ferric chloride. In a subsequent batch study with pH optimised for maximum sorption using 2% lime, ferric chloride (3%) added to two co-contaminated soils decreased As and Sb in solution after 7 days by at least 79%. Ferrihydrite (3%) and iron powder (3%) were less effective. Ferrihydrite (3%) was then used in a 12-week larger scale 'Cynodon dactylon' plant experiment that also considered plant bioavailability. Porewater As and Sb decreased by up to 90% but over the 12 week trial period no significant change in shoot or root metalloid concentrations was observed. The study demonstrates that iron-based amendments can be extremely effective for co-immobilisation of As and Sb in contaminated soils, but for large scale application amendment feasibility considerations and site specific pH moderation are essential.
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Citation |
Chemosphere, v.174, p. 208-217
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ISSN |
1879-1298
0045-6535
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Link | |
Publisher |
Elsevier Ltd
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Title |
Evaluation of amendments to reduce arsenic and antimony leaching from co-contaminated soils
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Type of document |
Journal Article
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Entity Type |
Publication
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