Physical Sciences and Mathematics Commons^™

The Influence Of Schwertmannite On Acidification And Sulfide Formation In Acid Sulfate Soil Landscapes, S Henderson, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

In coastal lowland acid sulfate soil (CLASS) landscapes, the iron hydroxy-sulfate mineral schwertmannite (Fe8 O8(OH)5.5(SO4)1.25) forms as pedofeatures such as macropore coatings and as ground surface layers. A series of experiments were conducted to examine the geochemical behavior of these pedofeatures under aerobic and anaerobic conditions. Samples of schwertmannite-rich pedofeatures were suspended in water over 10 days to examine their acidification behaviour. An anaerobic incubation was undertaken over 203 days to examine the influence of these pedofeatures on water quality and the reduction of sulfate and formation of sulfide. The results clearly show that the schwertmannite-rich pedofeatures, when introduced to …

Elemental Sulfur Dynamics In Coastal Lowland Acid Sulfate Soil Landscapes, Richard Bush, Edward Burton, Diane Fyfe

Associate Professor Edward D Burton

No abstract provided.

Schwertmannite In Acid Sulfate Subsoils And Associated Groundwater Geochemistry, Leigh Sullivan, Nadia Toppler, Yasmin Cabot, Richard Bush, Edward Burton

Associate Professor Edward D Burton

No abstract provided.

Geochemical Dynamics Of Sedimentary Iron In Waterways From Acid-Sulfate Soil Landscapes, Edward Burton, Richard Bush, Leigh Sullivan

Associate Professor Edward D Burton

The geochemical cycling of iron (Fe) is of great significance as a regulator of pH and contaminant mobility in soil, sediment and water. Pyrite (FeS2(s) oxidation is a particularly important aspect of Fe behaviour associated with ore/coal mining and coastal lowlands. The geochemical dynamics of Fe in the context of Acid Mine Drainage (AMD) environments has been studied intensively. In contrast, Fe geochemistry in waterways associated with coastal lowland Acid-Sulfate Soils (ASS) has received comparatively little research. Therefore, the objective of this study was to determine the solubility, mineralogy and geochemical dynamics of sedimentary Fe in acid-sulfate waterways associated with …

Fractionation And Extractability Of Sulfur, Iron And Trace Elements In Sulfidic Wetland Soils, Edward Burton, Richard Bush, Leigh Sullivan

Associate Professor Edward D Burton

Pyrite and other reactive iron-sulfide minerals are important to trace element behavior in many wetlands. These minerals provide sinks for potentially toxic trace elements that are introduced from anthropogenic and natural sources. The bioavailability and potential mobility of trace elements in wetland soils is therefore largely determined by the geochemical cycling of key Fe and S fractions. We examined Fe and S fractionation, and the related extractability of selected trace elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in wetland soils adjacent to a former municipal landfill in eastern Australia. The soil profiles were strongly reducing (Eh < -120 mV) and contained moderately high concentrations of pore-water sulfide (200 – 600 umol/L) and acid-volatile sulfide (AVS; 9.9 – 129 umol/g). Pyrite-S concentrations increased with depth, attaining concentrations as high as 251– 669 umol/g. The Degree of Sulfidisation was generally high (> 80%), indicating …

Copper Geochemistry In An Acidic, Sandy Soil: Sorption-Desorption, Aqueous Speciation And Mobility, Edward Burton, Ian Phillips, Darryl Hawker, Dane Lamb

Associate Professor Edward D Burton

The geochemical behavior of Cu in an acidic, sandy Podosol was examined. Sorption-desorption of Cu exhibited maximum linear distribution coefficients (Kd) at approx. pH 5. Observed depression of Kd values at pH > 5, were attributed to increased solubility of native Dissolved Organic Carbon (DOC) at higher pH and subsequent formation of poorly-sorbing Cu-DOC complexes. Speciation modelling with the MINTEQA2 code indicated that > 90 % of aqueous Cu was present as Cu-DOC complexes at pH > 5.5. The effect of Cu loading was examined with sorption isotherm analysis at pH 5 using both constant (1:2 and 1:10) and variable solid:solution ratio approaches. …

Conversion Of Naturally Occurring Schwertmannite To Hematite By Controlled Heating: Implications For Soluble Acidity And Titratable Actual Acidity, S Henderson, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

Naturally occurring schwertmannite (Fe8(OH)5.5(SO4)1.25), a result of acid sulfate soils (ASS) oxidation and severe acidification, has been identified as a labile source of iron, sulfate and acidity. Schwertmannite forms surface accumulations on coastal flood plains of eastern Australia. These flood plains are subject to wild fire events and fire-stick farming practices. Four samples of naturally occurring schwertmannite, from New South Wales coastal catchments, were converted to hematite by controlled heating. Complete conversion of schwertmannite to hematite (α-Fe2O3) occurred after exposure to temperatures of ≥500oC. The unheated schwertmannite and corresponding hematite samples were analysed for soluble acidity and Titratable Actual Acidity …

Investigation Of Sulfidic Sediments In A Coastal Lake Impacted By Urban Development, Bernard Powell, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

Lake Coombabah is a 2 km2, shallow, turbid estuarine system, surrounded by urbanized development situated within the Gold Coast Broadwater tidal system on the east coast of Australia; it is one of the fastest growing urban areas in the developed world 5. The region is an example of a system that demands urgent attention to the relationship between the environment and sustained development. The western shores of the Lake are heavily urbanised as is the upper catchment. Point and non-point source pollutants enter the system from urban sources (such as runoff from residential and commercial areas), acid sulfate soil disturbance, …

A Proposed Sequential Extraction Method For Metals Optimized For Acid Sulfate Soil Materials, Salirian Claff, Edward Burton, Leigh Sullivan, Richard Bush

Associate Professor Edward D Burton

Acid sulfate soils are an issue of international concern. Globally they are estimated to affect 24 million ha. Little work has been done on metal behavior in acid sulfate soils especially in Australia. Metals potentially raise a number of issues in the use and remediation of acid sulfate soils, however current risk assessment and management of these soils deals with acidity production only. To adequately manage the metal contamination risk some understanding of metal mobility and availability is required. Total metal analyses give little indication of the potential mobility of the metals, and little understanding of how mobility can change …

The Influence Of Naturally Occurring Schwertmannite On Sulfur Biomineralization In Coastal Acid Sulfate Soils Landscapes, S Henderson, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

In acid sulfate soil affected landscapes the iron oxide mineral schwertmannite (Fe8 (OH)5.5(SO4)1.25) is often abundant, forming coatings on ground surfaces and soil peds. Recent research has demonstrated that schwertmannite is a labile source of iron, sulfate and acidity, and may be the major mineral phase controlling water quality in these landscapes. We report experimental evidence that schwertmannite may also have an important role in the contemporary sulfur cycle, particularly sulfur reduction and accumulation of Monosulfidic-Black-Ooze (MBO). In-vitro anaerobic incubations were undertaken over 203 days to examine the influence of naturally occurring schwertmannite precipitates on the reduction and precipitation of …

Iron-Sulfur Biomineralisation And Arsenic Mobility In Acid-Sulfate Wetlands, Edward Burton, Scott Johnston, Richard Bush, Leigh Sullivan, Kym Watling, Annabelle Keene

Associate Professor Edward D Burton

Iron sulfide oxidation in drained coastal lowland soils liberates acidity, Fe and SO4, and leads to the accumulation of secondary Fe(III) minerals, such as schwertmannite (Fe8O8(OH)6SO4). Here we describe new insights on Fe-S biomineralisation and the associated mobility of As following the re-establishment of reducing conditions in reflooded acid sulfate wetlands. Our studies include controlled laboratorybased experiments on model systems as well as field-based observations on acid sulfate wetlands [1–-3]. When subjected to prolonged soil waterlogging as a result of wetland re-establishment, the bacterial reduction of schwertmannite-derived Fe(III) releases abundant Fe2+ (with up to 30 mM in affected groundwater) This …

Schwertmannitic Coatings On Subsoil Macropores Of Coastal Acid Sulfate Soil Landscapes In Eastern Australia And Implications For Groundwater Geochemistry, Leigh Sullivan, Yasmine Cabot, Richard Bush, Edward Burton

Associate Professor Edward D Burton

Schwertmannite (Fe8(OH)5.5(SO4)1.25) has recently been found to be the dominant mineral of iron precipitate accumulations from surface environments surrounding waterways (e.g. the sides of drains, and soil surface horizons) in acid sulfate soil landscapes in eastern Australia (Sullivan and Bush, 2004). In this study the yellowish-brown, orange-brown, and reddish-brown coatings on macropores (such as channels and planar pores) in 21 subsoil layers all located within acid sulfate soil ‘hotspots' in eastern Australia, were isolated and examined by both XRD and SEM-EDS to determine if schwertmannite was present. This examination determined that schwertmannite was detected in these coatings in 14 of …

Elemental Sulfur Dynamics In Acid Sulfate Soil Landscapes, Richard Bush, Edward Burton, Leigh Sullivan, Salirian Claff

Associate Professor Edward D Burton

The precipitation and dissolution of iron and sulfur minerals has a primary influence on water quality of acid sulfate affected landscapes (Fanning et al. 2002; Nordstrom 2000). The two key processes involved are the microbially mediated reduction and oxidation of sulfate and iron (Peine et al. 2000), which drive the geochemical store and flux of acidity. Iron sulfide minerals are the dominant store of acidity in sediments subjected to relatively stable reducing conditions (Fanning et al. 2002). However, we have found abundant elemental sulfur in the near-surface sediments of acid sulfate affected drain sediments that are subject to seasonally fluctuating …

Contemporary Iron Stone Formation Due To Acid Sulfate Soil Processes, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

One of the defining factors affecting soil formation is parent material: it may therefore be expected that sulfidic parent materials leave acid sulfate soil ‘inprints' within the soil profiles developing on such parent materials. Indeed, acid sulfate soil processes have been thought to be responsible for relict soil features (e.g. Fanning, pers. comm.; Rabenhorst et al 2004). This presentation describes the occurrence of a contemporary iron stone layer (i.e. an indurated layer cemented by iron minerals) within the channel of the Talbragar River in central New South Wales, in Eastern Australia. A long term study has been conducted at this …

Trends In Soil Science Education And Employment, J. Havlin, N. Balster, S. Chapman, D. Ferris, T. Thompson, T. Smith

Earth and Soil Sciences

During the last several decades, members of the SSSA have discussed several trends related to soil science education, including: (i) declining academic programs and course offerings at land grant universities, (ii) decreased enrollments, and (iii) improved employment opportunities for soil science graduates (SSSA, 2006; Ferris et al., 2010). The SSSA Advocacy/Education Task Force met in 2007 and concluded that quantitative survey information was needed to document trends in soil science academic programs, student enrollment, faculty, and job opportunities for graduates. Suggested survey topics included:

• Has the recognition of soil science as a distinct discipline increased or decreased?
• How has the …

Background Fluorescence In Groundwater From A Tropical Karst Island Aquifer, Michelle Hoffman

Michelle Hoffman

Background levels of four fluorescent compounds were monitored biweekly at thirteen sampling sites on Guam, consisting of subtidal and intertidal springs, dissolution fractures, and internal upland contact spring discharge, over a 13-month period from 2006 to 2007. Samples were compared to local precipitation and to seawater samples from four nearby reef flats. The data revealed that the concentrations of optical brighteners were consistently two orders of magnitude greater than either sodium fluorescein or rhodamine WT, while Eosine Y was rarely detected. Background levels in seawater, by comparison, accounted for 25% or more of the fluorescent compounds detected at the thirteen …

Improved Identification Of Sulfidic Soil Materials By A Modified Incubation Method, Leigh Sullivan, Nicholas Ward, Richard Bush, Edward Burton

Associate Professor Edward D Burton

This study examines the acidification behaviour and rate of sulfidic-sulfur oxidation in the incubation method that is currently used in soil taxonomies to identify sulfidic materials, for some clayey textured soil materials. ‘Sulfidic’ in these taxonomies identifies that a soil material is capable of becoming extremely acidic (i.e. pH < 4) as a result of oxidation of sulfide minerals contained in that soil material. As well as examining incubation slabs of acid sulfate soil materials with the standard 10 mm thickness, the utility of thinner (i.e. 2 mm thick) incubation slabs of these soil materials for identification of sulfidic soil materials …

Fe And S K-Edge Xas Determination Of Iron-Sulfur Species Present In A Range Of Acid Sulfate Soils: Effects Of Particle Size And Concentration On Quantitative Xanes Determinations, Kate Morgan, Edward Burton, Perran Cook, Mark Raven, Robert Fitzpatrick, Richard Bush, Leigh Sullivan, Rosalie Hocking

Associate Professor Edward D Burton

Acid sulfate soils (ASS) are soils and soft sediments in which sulfuric acid may be produced from iron sulfides or have been produced leaving iron oxyhydroxysulfates in amounts that have a long lasting effect on soil characteristics. If soil material is exposed to rotting vegetation or other reducing material, the Fe-oxyhydroxysulfates can be bacterially reduced to sulfides including disulfides (pyrite and marcasite), and Monosulfidic Black Ooze (MBO) a poorly characterised material known to be a mixture of iron sulfides (especially mackinawite) and organic matter. The chemistry of these environments is strongly affected by Fe and S cycling processes and herein …

Reductive Transformation Of Iron And Sulfur In Schwertmannite-Rich Accumulations Associated With Acidified Coastal Lowlands, Edward Burton, Richard Bush, Leigh Sullivan, David Mitchell

Associate Professor Edward D Burton

We examined the transformations of Fe and S associated with schwertmannite (Fe8O8(OH)6SO4) reduction in acidified coastal lowlands. This was achieved by conducting a 91 day diffusive-flux column experiment, which involved waterlogging of natural schwertmannite- and organic-rich soil material. This experiment was complemented by short-term batch experiments utilizing synthetic schwertmannite. Waterlogging readily induced bacterial reduction of schwertmannite-derived Fe(III), producing abundant pore-water FeII, SO4 and alkalinity. Production of alkalinity increased pH from pH 3.4 to pH 6.5 within the initial 14 days, facilitating the precipitation of siderite (FeCO3). Interactions between schwertmannite and FeII at pH 6.5 were found, for the first time, …

A Sequential Extraction Procedure For Acid-Sulfate Soils: Partitioning Of Iron, Salirian Claff, Leigh Sullivan, Edward Burton, Richard Bush

Associate Professor Edward D Burton

A new sequential extraction scheme for acid sulfate soil materials has been evaluated for iron partitioning in a range of synthetic iron-bearing minerals and natural acid sulfate soil materials. This sequential extraction procedure employs six steps to quantify (1) exchangeable (magnesium chloride extractable), (2) acid (hydrochloric acid) soluble, (3) reactive organic-bound (pyrophosphate extractable), (4) crystalline oxide (citrate buffered dithionite (CBD)) extractable, (5) pyrite-bound (nitric acid extractable) and (6) residual (acid/peroxide digestible) forms of iron. Given its intended use for acid sulfate soil materials that frequently contain pyrite, a primary aim of this new sequential extraction procedure was to differentiate iron …

Temporal And Spatial Assessment Of Evaporation, Transpiration, And Soil Moisture Redistribution, Brian M. Bird

UNLV Theses, Dissertations, Professional Papers, and Capstones

At a native stand of creosote bush (Larrea tridentata) in North Las Vegas, a rainfall simulation study was conducted over a 12 month period from October 2005 to October 2006. Simulated rainfall occurred during the winter, spring, summer, and fall periods. Rainfall simulation systems were positioned on each of 12 plots, each containing a single creosote bush. Simulated rainfall events occurred at night with multiple short pulses designed to maximize infiltration while minimizing ponding. Yearly simulated rainfall amounts were set at 0, 15, 30 and 60 cm (replicated three times) and were approximately 0, 1.5, 3.0 and 6.0 times the …

Cockatoo Sands Soil Survey : Assessment Of The Potential Irrigation Areas, Kununurra Area, East Kimberley, Henry Smolinski, Kus Kuswardiyanto, Justin Laycock

Resource management technical reports

No abstract provided.

Factors Influencing Soil Moisture At The Hillslope Scale In A Semi-Arid Mountainous Environment, Ivan John Geroy

Boise State University Theses and Dissertations

Soil moisture couples ground, surface, and atmospheric water interactions via the processes of evapotranspiration, infiltration, and runoff generation (Grayson et al., 1997). Consequently, understanding the factors that influence the spatial distribution of soil moisture is vitally important to the accurate conceptualization and modeling of watershed processes. Typically, topographic indexing methods for the prediction of soil moisture have been studied in temperate or humid areas where the soil profile is often saturated and redistribution of soil moisture is driven by topography (Famiglietti et al., 1998; Grayson et al., 1997; Western et al., 1999). By contrast, in semi-arid environments, long periods of …

An Investigation For The Need Of Secondary Treatment Of Residential Wastewater When Applied With A Subsurface Drip Irrigation System, Boone S. Hillenbrand

Masters Theses

The objective of this study was to investigate the need for domestic wastewater to receive secondary treatment when being applied to the soil by subsurface drip irrigation (SDI). SDI uniformly distributes wastewater into the soil, which optimizes the soil’s chemical, physical, and biological capacity to remove waste constituents. Because of these advantages, many regulatory jurisdictions are allowing SDI at sites that previously were prohibited from using conventional trench-based soil application systems because of shallow soil restrictions. However, most of these regulatory agencies also require that the wastewater receives secondary treatment (dissolved organic carbon reduction) before the SDI system. At issue …

The Effects Of Changes In Water Content On Uranium(Vi) Leaching In Sediment Mixtures Containing Gravel, Andrew Weber Moore

Masters Theses

This study is aimed at understanding the physical and chemical effects that changes in water content have on uranium leaching in sediment containing gravel. It was hypothesized that leaching will be more efficient under unsaturated conditions because flow will be restricted to the smallest pores and will have the most contact with the uranium contaminated sediment. Under saturated conditions, a large portion of the flow will bypass the < 2 mm material, and in turn not come into contact with uranium contaminated material. Batch adsorption and desorption experiments were performed on < 2 mm ERDF sediment to determine the linearity and reversibility of sorption processes and to aid in the interpretation of the leaching experiments. Results of the desorption experiments on aged, contaminated sediments show that the mass percent of sorbed U(VI) released to solution decreased as the sorbed concentration of U(VI) decreased. The opposite trend was observed on freshly contaminated sediments. This indicated that aging increased U(VI) affinity for the solid phase and was attributed to either the crystallization of calcite, which incorporated a portion of the sorbed U(VI) as it crystallized, or the presence of voids in basaltic lithic fragments accessed by diffusion. Column leaching experiments were performed at two water contents on artificially contaminated sediment collected from the Department of Energy’s (DOE) Hanford Site, Washington state. The sediment contained 81.3% gravel (> 2 mm) by mass. Non-reactive tracers were well fit with the convection-dispersion equation (CDE) at both high and low water contents indicating physical equilibrium. The column experimental data were fitted to an …

Water Erosion Hazard Assessment Of The Lort And Young Rivers Catchment, Karen Holmes, John Andrew Simons, B Marillier, N Callow, Paul Galloway

Resource management technical reports

No abstract provided.

A Study Of Soil Development On Marine And Stream Terraces Of Swanton Pacific Ranch, Davenport, Ca, Genevieve M. Widrig, Kristine W. Johnson, Anna E. Tornincasa

Earth and Soil Sciences

No abstract provided.

The Influence Of Vegetation And Landscape Position On Soil Temperature Change In A Sagebrush-Steppe Eastern Sierra Environment: Implications On Soil Taxonomy, Nathan Michael Lurie

Earth and Soil Sciences

Soil temperature is a parameter that has been studied for a considerable time and from many different perspectives. However, relatively few studies have been conducted for taxonomic purposes and fewer still have focused on how changes in soil temperature related to global climate change may affect soil taxonomy. Soil temperature regimes are used to subdivide soils with similar properties that exist in dissimilar climate zones requiring different management practices depending on intended use. Seven sites with variable surficial features were used for this study within a cohesive sagebrush-steppe Eastern Sierra glacial moraine landform. Soil temperature was measured once a month …

Management And Control Plan For Zinfandel Vines In South Paso Robles, Ca., Tanner E. Campbell

Earth and Soil Sciences

Zinfandel, also known as Zin, is a red skinned variety of wine grape very popular in California. The wines produced from Zinfandel grapes have an intense fruitiness and luscious texture. Production is extremely variable throughout California and is dependent upon, climate, soil fertility, crop level management practices, and irrigation. This study was conducted to determine the on site soil physical and chemical properties as a means to obtain optimal yields and fruit quality. The A & L Western Agriculture Laboratories performed comprehensive fertility analysis to determine the concentrations of the plant essential nutrients, organic matter, electrical conductivity, cation exchange capacity, …

Fragaria Species Grown In A Greenhouse Cropping System Chemigated By Phosfite® And Bacillus® In Subsidence Of Phytophthora Fragariae And Verticillium Dahliae, Russell L. Morgan

Earth and Soil Sciences

Strawberry yields depend directly on infestation of Phytophthora fragariae and Verticillium dahliae in correspondance to the use of Phosfite and Bacillus. The objective is to find understanding of newly administered techniques in prevention of Phytophthora fragariae and Verticillium dahliae and prohibiting the use of Methyl Bromide. Application of Phosfite and Bacillus on patented Fragariae species to identify utilization of P and ZN forms and their aid in prevention of Phytophthora and Verticillium species. In the Plots on the western bench the developmental symptoms of PRR disease were absent within all infested soil containers containing the FHS-1 crop. In the plots …