Journal article
Enrichment and heterogeneity of trace elements at the redox-interface of Fe-rich intertidal sediments
Chemical Geology, Vol.383, pp.1-12
2014
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Abstract
<p><p id="x-x-x-sp0005">Redox-interfacial sediments can undergo radical geochemical changes with oscillating tides. In this study, we examine trace element enrichment and availability, at both landscape and pedon-scales, in the surface sediments of a remediating acidic tidal wetland. Fe-rich sediments at the surface-water interface (0–10 mm in depth) were collected across an elevation gradient spanning the supratidal to subtidal range. These sediments were analysed for solid phase Fe fractions and trace elements (As, Pb, Cr, Cu, Mn, Ni, Zn, V, B, Co, Mo, Ba and U) via dilute HCl-extractions and total digests. Their concentrations were compared with those of underlying (0.05–0.65 m in depth) former sulfuric horizon sediments of a coastal acid sulfate soil (CASS). Reactive Fe was enriched at the redox interface by up to 16 times (197 g Fe/kg) that of the former sulfuric horizon. The proportion of total trace elements associated with reactive phases was high in interfacial sediments, representing over 90% of B and U and 50% of Pb, Cu, Zn, V and Ba extractable by dilute HCl. The interfacial sediments were particularly enriched in reactive Cr, Cu, Ni, Zn, B, Mo and U, with reactive B, Mo and U concentrations between 5 and 10 times greater than in the former sulfuric horizon. Surface enrichment of trace elements is strongly co-associated with Fe(III) mineralisation, likely via sorption and co-precipitation processes. Enrichment is highly spatially heterogeneous and is strongly influenced by elevation and tidal zonation at a landscape-scale and by sediment micro-topography and preferential advective transport via surface connected macropores at the pedon-scale. The results from this study provide new insights to the processes influencing trace element enrichment in Fe-rich redox-interfacial sediments across a remediating acidic tidal wetland.</p>
Details
- Title
- Enrichment and heterogeneity of trace elements at the redox-interface of Fe-rich intertidal sediments
- Creators
- Annabelle F Keene - Southern Cross UniversityScott G Johnston - Southern Cross UniversityRichard T Bush - Southern Cross UniversityEdward D Burton - Southern Cross UniversityLeigh A Sullivan - Southern Cross UniversityMatthew Dundoon - C2HM HILL AustraliaAngus E McElnea - Department of Science, Information Technology, Innovation and the Arts, Queensland GovernmentC Doug Smith - Department of Science, Information Technology, Innovation and the Arts, Queensland GovernmentCol R Ahern - Department of Science, Information Technology, Innovation and the Arts, Queensland GovernmentBernard Powell - Department of Science, Information Technology, Innovation and the Arts, Queensland Government
- Publication Details
- Chemical Geology, Vol.383, pp.1-12
- Grants
- A national demonstration site for innovative acid sulfate soil management, 20100095, Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE)
- Identifiers
- 1374; 991012822022802368
- Academic Unit
- Science; Southern Cross GeoScience; Faculty of Science and Engineering
- Resource Type
- Journal article