NSU Research Contributions
Title : Dissolved Organic Matter Sources and Consequences for Iron and Arsenic Mobilization in Bangladesh Aquifers
Authors : Natalie mladenov, Yan zheng, Matthew p. Miller, Diana R. Nemergut, Teresa legg, Bailey Simone,Clarrisa Hageman, M. Moshiur Rahman, K. Matin Ahmed, Diane M. Macknight
Abstract : Iron (Fe) and dissolved organic matter (DOM) cycling have been implicated in arsenic mobilization via microbially mediated Fe oxide reduction. To evaluate the sources and multiple rolesofDOMinBangladeshaquifers,weconductedspectroscopic analyses on various types of surface water and groundwater samples from a site representative of aquifer chemistry and hydrology.Surfacewatercontainedhumicsubstanceswithoxidized quinone-like moieties and high concentrations of labile microbially derived DOM. In contrast, in shallow groundwater where dissolved iron and arsenic concentrations were high, the quinone-like moieties of humic substances were more reduced, with less abundant labile DOM than that of surface water. Instead, DOM at these depths was characterized by terrestrial (plant/ soil) signatures. A sediment microcosm experiment demonstrated that Fe(II) and terrestrially derived DOM were released from sediment over time. The results provide new evidence to support a dual role of natural DOM in Bangladesh aquifers (1) as a labile substrate for Fe- and humic-reducing bacteria and (2) as anelectron shuttle viahumic substancestoenhancemicrobial iron reduction. Fluorescence index, amino acid-like fluorescence, andredox index may serve as useful indicators of the type of DOM likely to be involved in Fe solubilization and potentially As mobilization reactions.
| Journal : Environmental Science & Technology | Volume : 44 | Year : 2009 | Issue : 1 |
| Pages : 123-128 | City : | Edition : | Editors : |
| Publisher : | ISBN : | Book : | Chapter : |
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