A molecular-level understanding of the surface complexation reactions between ecotoxic heavy metals and mineral surfaces is essential for determining their environmental fate. Many studies have investigated the surface complexes of elements on different mineral surfaces, but few studies have performed surface complexation modelling to determine the specific equilibrium constants for these complexes. To the best of our knowledge, no study has applied appropriate equilibrium constant data from surface complexation modelling for determining the stability and bioaccessibility of ecotoxic elements at actual sites of concern. This is the goal of this study. Chapter 1 is a review of the scale of metal contamination in the UK, the sources and the common methods of environmental impact assessment. This Chapter describes how surface complexation models can provide the most accurate means of modelling metal partitioning onto environmentally relevant mineral surfaces. Chapters 2 and 3 are surface complexation modelling studies of Pb and Zn respectively, onto the highly reactive and environmentally ubiquitous Mn oxide mineral phase, birnessite (o-Mn02). Chapter 4 is a geochemical survey of the River Axe Valley in Somerset, England. This area has been identified as having a high risk of contamination from mining, but has not received the same depth of investigation compared to other areas in the UK. This Chapter provides background information on this area, and investigates the mineralogy of the mine site soils, the caves through which the surface waters drain and the River Axe floodplain. The surface complexation models derived in Chapters 2 and 3 are successfully applied to model the partitioning of Pb and Zn in this setting, and assist in understanding the possible risk from the mine-derived metal-bearing sediment. Chapter 5 is a summary of the information required for the successful application of surface complexation models for site investigations in general, and gives an appraisal of their uses in future studies.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:687595 |
| Date | January 2014 |
| Creators | Bacon, Charles Guy David |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0167 seconds