Reactive oxygen species production on oxygenation of subsurface sediments. This project aims to examine the nature, extent and effect of redox processes in subsurface environments. Reactive oxygen species, including hydrogen peroxide, superoxide and hydroxyl radicals, transform and affect redox-active substances in the environment such as arsenic, uranium and natural organic matter (which may be oxidised to carbon dioxide). Production of significant quantities of reactive oxygen species on oxyge ....Reactive oxygen species production on oxygenation of subsurface sediments. This project aims to examine the nature, extent and effect of redox processes in subsurface environments. Reactive oxygen species, including hydrogen peroxide, superoxide and hydroxyl radicals, transform and affect redox-active substances in the environment such as arsenic, uranium and natural organic matter (which may be oxidised to carbon dioxide). Production of significant quantities of reactive oxygen species on oxygenation of subsurface sediments through actions such as aquifer recharge and high flow events may alter the form and mobility of trace elements and influence the cycling of carbon and eventual efflux of carbon dioxide to the atmosphere. This project will examine the nature, extent and effect of these redox processes in selected subsurface environments. This research could have implications for contaminant transformation and fate and carbon cycling.Read moreRead less
Redox transformations of natural organic matter. This project aims to determine the electron transfer (redox) properties of terrestrially and microbially-derived natural organic matter (NOM) and the implications of these redox characteristics to reactive oxygen species generation, metals transformation and carbon cycling. Experimental and computational studies using model compounds containing quinone and thiol-containing functional groups as well as well-characterised humic substances and algal ....Redox transformations of natural organic matter. This project aims to determine the electron transfer (redox) properties of terrestrially and microbially-derived natural organic matter (NOM) and the implications of these redox characteristics to reactive oxygen species generation, metals transformation and carbon cycling. Experimental and computational studies using model compounds containing quinone and thiol-containing functional groups as well as well-characterised humic substances and algal exudates will be undertaken under both dark and light conditions. Kinetic models of these processes will be developed enabling prediction of the impact of NOM-mediated electron transfer processes on oxidant generation, metals transformation and carbon cycling.Read moreRead less
New perspectives on arsenic speciation and fate in anoxic aqueous environments: Resolving unexplored interactions with the sulfur cycle. Using exciting new experiments and innovative analyses, this project will provide transformational insights into how sulfur cycling in the Earth’s critical zone affects arsenic speciation and fate. The project will resolve, for the first time, unexplored interactions between arsenic geochemistry and the low-temperature formation and transformation of metastable ....New perspectives on arsenic speciation and fate in anoxic aqueous environments: Resolving unexplored interactions with the sulfur cycle. Using exciting new experiments and innovative analyses, this project will provide transformational insights into how sulfur cycling in the Earth’s critical zone affects arsenic speciation and fate. The project will resolve, for the first time, unexplored interactions between arsenic geochemistry and the low-temperature formation and transformation of metastable iron sulfide minerals. The outcomes will provide crucially important new perspectives on arsenic geochemistry in anoxic soils, sediments and groundwater systems.Read moreRead less
Interactions between antimony and the sulphur cycle. This project aims to unravel unexplored interactions between the sulphur cycle and fundamentally important aspects of antimony geochemistry in the Earth’s critical zone. This project will resolve interactions between antimony geochemistry and the low-temperature formation and transformation of metastable iron sulphide minerals. The outcomes are expected to provide crucially important perspectives on antimony geochemistry in anoxic soils, sedim ....Interactions between antimony and the sulphur cycle. This project aims to unravel unexplored interactions between the sulphur cycle and fundamentally important aspects of antimony geochemistry in the Earth’s critical zone. This project will resolve interactions between antimony geochemistry and the low-temperature formation and transformation of metastable iron sulphide minerals. The outcomes are expected to provide crucially important perspectives on antimony geochemistry in anoxic soils, sediments and groundwater systems. This understanding should lead to more accurate geochemical risk assessments and better site treatment strategies for environmental antimony contamination.Read moreRead less
New perspectives on iron oxide transformations in oxic and anoxic aqueous environments: implications for iron bioavailability and contaminant mobility. Transformations in the form and reactivity of iron oxides in oxic and anoxic aqueous environments are considerably more dynamic than previously thought. This project will examine the nature and extent of these transformations and elucidate their impact on supply of iron to organisms and mobility of uranium and arsenic in groundwaters.
A new paradigm for the accumulation and persistence of metastable iron sulphides in sulphidic soils. Metastable iron sulphide minerals have a critical role in controlling surface- and ground-water quality. This project will transform our understanding of the environmental geochemistry of metastable iron sulphides in sulphidic soils. This will greatly enhance our ability to predict and manage water quality in a wide range of important aquatic systems.