Iron reductive dissolution in vadose zone soils: Implication for groundwater pollution in landfill impacted sites
| Autor: | Timothy G. Townsend, Willie G. Harris, Akua B. Oppong-Anane, Jean-Claude J. Bonzongo, Katherine Y. Deliz Quiñones |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Oxide minerals 0208 environmental biotechnology 02 engineering and technology 010501 environmental sciences 01 natural sciences Pollution 020801 environmental engineering chemistry Geochemistry and Petrology Environmental chemistry Groundwater pollution Soil water Vadose zone Environmental Chemistry Environmental science Organic matter Leachate Dissolution Groundwater 0105 earth and related environmental sciences |
| Zdroj: | Applied Geochemistry. 94:21-27 |
| ISSN: | 0883-2927 |
| DOI: | 10.1016/j.apgeochem.2018.05.001 |
| Popis: | Iron (Fe) contamination of groundwater has become a problem of concern at a number of landfill impacted locations, and long-term monitoring studies suggest that the reductive dissolution of iron (hydr)oxide minerals present in soils and aquifer sediments could be one the sources of dissolved Fe measured in impacted aquifers. In this study, vadose zone soil samples were collected along a gradient emphasizing differences in both soil water saturation levels and degrees of crystallization of Fe-minerals. Collected soil samples were analyzed for pH, organic matter content, particle size distribution, and Fe speciation into amorphous and crystalline fractions. Batch experiments were conducted under anaerobic conditions using soil slurries with (treatments) or without (controls) landfill leachate addition to the liquid phase. Under the experimental conditions used in this study, tested soils released Fe primarily via reductive dissolution pathways, with rates ranging from ∼0.3 to 12 mg Fe/kg.day. However, no clear trend was evident between the amount of Fe released and the crystallinity degrees of the iron minerals present in the tested soils. The addition of organic carbon sources to prepared vadose soils slurries fueled the microbial driven Fe-reductive dissolution, suggesting that organic-rich landfill leachate would play a significant role in the dissolution of iron (hydr)oxide minerals, and potentially in the mobilization of toxic metals co-precipitated with or adsorbed onto iron (hydr)oxide minerals. |
| Databáze: | OpenAIRE |
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