Chief Investigator

Richard T Bush


Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (project no. 6-6-01-06/07 ‘A national demonstration site for innovative acid sulfate soil management’).

Grant ID


School or Research Centre

Southern Cross Geoscience

Lead Partner Organisation

Southern Cross University


Professor Richard Bush, Director Southern Cross Geoscience, Southern Cross University, PO Box 157, Lismore NSW 2480,


Acid sulfate soils, Iron, Trace elements, Tidal wetland, Remediation


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 tidalwetland. Fe-rich sediments at the surface-water interface (0–10mmin 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 coassociated 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.

Data Collection Start Date


Data Collection End Date


Creative Commons License

Creative Commons Attribution-Noncommercial-Share Alike 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

FoR Code

040600 Physical Geography and Environmental Geoscience, 040200 Geochemistry, 050300 Soil Sciences

Viewing Instructions

Each layer has a number.

Data Processing

Excel, SPSS

Surface_oxide_samples_worksheet.csv (28 kB)
Surface Oxide Samples
Total_elevation_sorted_worksheet.csv (5 kB)
Total Elevation
Total_M_Enrichment.csv (26 kB)
Total M Enrichment
HCI_M_Enrichment_Worksheet.csv (18 kB)
HCI_M Enrichment
Water_soluble_M_enrichment.csv (9 kB)
Water Soluble M Enrichment
Quadrat_Fe_and_As.csv (11 kB)
Quadrat Fe and As
Quadrat_Total_Fe_Standard_Worksheet.csv (1 kB)
Quadrat Total Fe Standard
Quadrat_Total_Fe_conc_HCI_Worksheet.csv (5 kB)
Quadrat Total Fe conc HCI
Quadrat_Total_Metals__Conc_HCI_Worksheet.csv (7 kB)
Quadrat Total Metals Conc HCI
Correlations_Worksheet.csv (24 kB)
Quadrat_Correlations_Worksheet.csv (2 kB)
Quadrat Correlations
Quadrat_Total_As_Conc_HCI_Worksheet.csv (5 kB)
Quadrat Total As Conc HCI


Spatial Coverage