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Full-Text Articles in Physical Sciences and Mathematics

Seawater Causes Rapid Trace Metal Mobilisation In Coastal Lowland Acid Sulfate Soils: Implications Of Sea Level Rise For Water Quality, Vanessa Wong, Scott Johnston, Edward Burton, Richard Bush, Leigh Sullivan, Peter Slavich Jul 2013

Seawater Causes Rapid Trace Metal Mobilisation In Coastal Lowland Acid Sulfate Soils: Implications Of Sea Level Rise For Water Quality, Vanessa Wong, Scott Johnston, Edward Burton, Richard Bush, Leigh Sullivan, Peter Slavich

Associate Professor Edward D Burton

Coastal floodplains are highly vulnerable to inundation with saline water and the likelihood of inundation will increase with sea level rise. Sediment samples from floodplains containing coastal lowland acid sulfate soils (CLASS) in eastern Australia were subjected to increasing seawater concentration to examine the probable effects of sea level rise on acidity and metal desorption. Ten soils were mixed with synthetic seawater concentrations varying from 0% to 100% at a solid:solution ratio of 1:10 for 4 h. There was a slight decrease in pH (≈0.5 units) with increasing seawater concentration following treatment, yet, calculated acidity increased significantly. In most soil …


Monosulfidic Black Ooze Accumulations In Sediments Of The Geographe Bay Area, Western Australia, Nicholas Ward, Richard Bush, Edward Burton, S Appleyard, S Wong, Leigh Sullivan, Paul Cheeseman Jul 2013

Monosulfidic Black Ooze Accumulations In Sediments Of The Geographe Bay Area, Western Australia, Nicholas Ward, Richard Bush, Edward Burton, S Appleyard, S Wong, Leigh Sullivan, Paul Cheeseman

Associate Professor Edward D Burton

Mobilisation of sedimentary monosulfidic black ooze (MBO) may result in rapid deoxygenation and acidification of surface waters, and release of potentially toxic metals. This study examines the extent and nature of MBO accumulation in the Geographe Bay area, Western Australia. MBO accumulations were found to be widespread in benthic sediments of the Geographe Bay area with acid-volatile sulfide (AVS) contents as high as 320 μmol g−1. The MBO materials often had unusually high dissolved sulfide (S−II) concentrations in their pore-waters (up to 610 mg L−1) and elevated elemental sulfur (S0) contents (up to 51 μmol g−1). Dissolved S−II is able …


Climate Change: A Frontier For Acid Sulfate Soil Research, Richard Bush, Leigh Sullivan, Scott Johnston, Edward Burton, Vanessa Wong, Annabelle Keene Jul 2013

Climate Change: A Frontier For Acid Sulfate Soil Research, Richard Bush, Leigh Sullivan, Scott Johnston, Edward Burton, Vanessa Wong, Annabelle Keene

Associate Professor Edward D Burton

Sea-level is predicted to continue to rise this century, threatening the integrity of coastal floodplains throughout the world. The low-lying elevation of much of the 17 million ha of acid-sulfate soils that occur worldwide, renders these landscapes particularly vulnerable to the impacts of climate change. Acid sulfate soils landscapes are regulated by redox driven biogeochemical processes that are sensitive to watertable dynamics, tidal exchange and temperature. The increased likelihood of extreme weather events such as drought and floods and rising global temperatures are directly relevant to the redox and hydrological processes that influence acid sulfate soil behaviour and their impact …


Seawater-Induced Mobilization Of Trace Metals From Mackinawite-Rich Estuarine Sediments, Vanessa Wong, Scott Johnston, Edward Burton, Richard Bush, Leigh Sullivan, Peter Slavich May 2013

Seawater-Induced Mobilization Of Trace Metals From Mackinawite-Rich Estuarine Sediments, Vanessa Wong, Scott Johnston, Edward Burton, Richard Bush, Leigh Sullivan, Peter Slavich

Associate Professor Edward D Burton

Benthic sediments in coastal acid sulfate soil (CASS) drains can contain high concentrations (∼1–5%) of acid volatile sulfide (AVS) as nano-particulate mackinawite. These sediments can sequester substantial quantities of trace metals. Because of their low elevation and the connectivity of drains to estuarine channels, these benthic sediments are vulnerable to rapid increases in ionic strength from seawater incursion by floodgate opening, floodgate failure, storm surge and seasonal migration of the estuarine salt wedge. This study examines the effect of increasing seawater concentration on trace metal mobilization from mackinawite-rich drain sediments (210–550 μmol g−1 AVS) collected along an estuarine salinity …


Arsenic Mobilization And Iron Transformations During Sulfidization Of As(V)-Bearing Jarosite, Scott Johnston, Edward Burton, Annabelle Keene, Britta Planer-Friedrich, Andreas Voegelin, Mark Blackford, Greg Lumpkin Apr 2013

Arsenic Mobilization And Iron Transformations During Sulfidization Of As(V)-Bearing Jarosite, Scott Johnston, Edward Burton, Annabelle Keene, Britta Planer-Friedrich, Andreas Voegelin, Mark Blackford, Greg Lumpkin

Associate Professor Edward D Burton

Jarosite (KFe3(SO4) 2(OH)6) is an important host-phase for As in acid mine drainage (AMD) environments and coastal acid sulfate soils (CASS). In AMD and CASS wetlands, jarosite may encounter S(−II) produced by sulfate reducing bacteria. Here, we examine abiotic sulfidization of As(V)-bearing K-jarosite at pH 4.0, 5.0, 6.5 and 8.0. We quantify the mobilization and speciation of As and identify corresponding Fe mineral transformations. Sulfide-promoted dissolution of jarosite caused release of co-precipitated As and the majority of mobilized As was re-partitioned to a readily exchangeable surface complex (AsEx). In general, maximum As mobilization occurred in the highly sulfidized end-members of …


Decoupling Between Water Column Oxygenation And Benthic Phosphate Dynamics In A Shallow Eutrophic Estuary, Peter Kraal, Edward Burton, Andrew Rose, Michael Cheetham, Richard Bush, Leigh Sullivan Apr 2013

Decoupling Between Water Column Oxygenation And Benthic Phosphate Dynamics In A Shallow Eutrophic Estuary, Peter Kraal, Edward Burton, Andrew Rose, Michael Cheetham, Richard Bush, Leigh Sullivan

Associate Professor Edward D Burton

Estuaries are crucial biogeochemical filters at the land–ocean interface that are strongly impacted by anthropogenic nutrient inputs. Here, we investigate benthic nitrogen (N) and phosphorus (P) dynamics in relation to physicochemical surface sediment properties and bottom water mixing in the shallow, eutrophic Peel-Harvey Estuary. Our results show the strong dependence of sedimentary P release on Fe and S redox cycling. The estuary contains surface sediments that are strongly reducing and act as net P source, despite physical sediment mixing under an oxygenated water column. This decoupling between water column oxygenation and benthic P dynamics is of great importance to understand …


Iron And Arsenic Cycling In Intertidal Surface Sediments During Wetland Remediation, Scott Johnston, Annabelle Keene, Edward Burton, Richard Bush, Leigh Sullivan Jan 2013

Iron And Arsenic Cycling In Intertidal Surface Sediments During Wetland Remediation, Scott Johnston, Annabelle Keene, Edward Burton, Richard Bush, Leigh Sullivan

Associate Professor Edward D Burton

The accumulation and behavior of arsenic at the redox interface of Fe-rich sediments is strongly influenced by Fe(III) precipitate mineralogy, As speciation, and pH. In this study, we examined the behavior of Fe and As during aeration of natural groundwater from the intertidal fringe of a wetland being remediated by tidal inundation. The groundwater was initially rich in Fe2+ (32 mmol L−1) and As (1.81 μmol L−1) with a circum-neutral pH (6.05). We explore changes in the solid/solution partitioning, speciation and mineralogy of Fe and As during long-term continuous groundwater aeration using a combination of chemical extractions, SEM, XRD, and …