Project description
Probing the mechanisms that control chromium mobilisation
Long-term pollution mitigation measures require a better understanding of the biogeochemical processes that regulate the behaviour of trace metals, such as chromium, over time. While stable chromium isotopes can be used to effectively assess the element’s biogeochemical and redox cycles, few studies have investigated the ligand-induced chromium mobilisation mechanism. Funded by the Marie Skłodowska-Curie Actions programme, the CHROMA project will investigate whether chromium can be mobilised by organic ligands under various environmental conditions. To this end, it will combine field sampling, isotopic analysis and geochemical modelling. Project results will help reveal more about how organic ligands affect the chromium redox cycle and how anthropogenic activities impact on the subsurface environment.
Objective
Long-term pollution mitigation requires a better understanding of the biogeochemical processes that regulate the behavior and fate of trace metals, such as chromium (Cr), in subsurface environments. The emerging role of organic ligands, including siderophores and organic acids, in the speciation, bioavailability and mobility of trace metals is receiving increasing attention. However, the relative importance of the opposing Cr reduction and mobilization processes in sediments remain poorly constrained, and the Cr-ligand interaction has not been explicitly determined. Whilst stable isotope compositions of Cr are an effective tool for assessing biogeochemical cycling and redox processes, there have been few studies reporting the isotope effect of ligand-induced Cr mobilization. This project combines an interdisciplinary set of field sampling, controlled experiments, isotopic analysis alongside geochemical modelling, aiming to test the hypothesis that (1) solid Cr can be effectively remobilized by organic matter in reduced environment despite Cr reduction, and (2) aqueous Cr can be stabilized in the form of organic complexes with a distinct Cr isotope signature. The extent and mechanism of Cr mobilization by organic ligands under various environmental conditions will be quantified. Stable Cr isotopes in sediment pore water will be accurately determined and validated as a tracer for Cr-ligand complexation. The fate of Cr in relation to Fe and organic ligands in sediments will be predicted. This project will shed new light on the role of organic ligands in the Cr redox cycle, and will reveal the sensitivity of subsurface environments to anthropogenic activities. This project includes both the transfer of knowledge to the host institution and the training of the candidate in advanced techniques. Results from this project will be disseminated to the environmental science and geochemistry research community and to the wider public.
Fields of science
Programme(s)
Funding Scheme
MSCA-IF-EF-ST - Standard EFCoordinator
1010 Wien
Austria