Environmental Mineralogy

Aims

• To establish and quantify the processes controlling the redistribution of chemical elements in the surface environment through mineral breakdown due to fluid-mineral interactions.
• To provide relevant information on element mobility and mineral stability for associated studies on water quality and bioavailability of toxic elements.
• To develop techniques on the stabilisation of toxic metals in the environment, particularly in developing countries and around sites of mining and mineral processing.

Research team

• Dr Eva Valsami-Jones
• Dr Bill Dubbin
• Dr Javier Cuadros
• Dr Ben Williamson
• Dr Elena Hutchens (Marie Curie Fellow)
• Mr Ross Sneddon (Research Assistant)
• Ms Jacqueline van der Houwen (PhD student)
• Ms Alison Carruthers (PhD student)
• Mr Mikel Orueetxebarria (PhD student)

Current projects

• Heavy metal immobilisation in soils via phosphate formation: This project aims to develop methodologies of fixing heavy metals, by transforming them into insoluble (and therefore non-bioavailable) metal phosphates. Laboratory studies carried out at the Museum on experimental phosphate formation suggest that a micro-crystalline form of apatite, such as occurs in bone-meal, could be a more effective source of phosphorus, as it has a higher solubility than rock apatite, but is not so soluble that it is readily leached from soil. The phosphorus released from the bone-meal combines with the metals to form metal phosphates within days to weeks (depending on experimental conditions) and reduces metal availability. This has been demonstrated in laboratory batch and column experiments, and is currently being studied in a field trial.
• Phase quantification of contaminated soils: Metal fixing in contaminated soils via the formation of new insoluble phases often requires challenging phase identification and quantification, to demonstrate remediation progress. We have recently developed a rapid and accurate method for phase quantification using the NHM's PSD X-ray diffractometer. This project will develop quantification methodologies specifically for soils, and will test trial mixtures, which will be used to calibrate the limits of the technique prior to the examination of remediated soils.
• Studies of sorption of heavy metals by clay minerals: Clays often represent a short-term sink of heavy metals in soils, because of their adsorptive properties. This study is part of our efforts to better understand the controls on heavy metal residence in soils, in order to better target remediation methods. This study investigates the NMR spectra of Cd-exchanged smectites, in order to assess the mode of cadmium adsorption on these smectites.
• Mechanisms of release, transport and precipitation of arsenic in the environment: The chemistry of arsenic is complex and strongly influenced by environmental conditions. In order to better understand arsenic mobility, this project combines adsorption/desorption studies with a thorough understanding of the mineral substrates and their role in controlling arsenic mobility. The work involves studies of mineral reactivity and involves computational simulations (in collaboration with the Royal Institute/University College London).
• Calcium phosphate precipitation in wastewaters as a mechanism of phosphorus recovery: This is research into a sustainable alternative to current methods of phosphorus removal from wastewaters. Our research aims to develop technology that will allow a calcium phosphate of recyclable quality to be produced during wastewater treatment. In terms of research, we investigate the precipitation kinetics of calcium phosphates, with particular emphasis on the effects of organic ligands that may act as inhibitors.
• Microbial mineral weathering: This is an investigation of the mechanisms involved in mineral dissolution by heterotrophic bacteria. The study will consider the factors that affect the rate and extent of mineral dissolution, including bacterial attachment to surfaces. Ultimately, the aim of this project is to assess whether micro-organisms play a role in the circulation of base cations on the Earth's surface.
• Abiotic degradation of organic contaminants on Mn oxides: Naturally occurring mineral components in soils, such as manganese oxides, have the potential to degrade pesticides and therefore reduce their potential threat. The project aims to study the degradation of a range of different pesticides (eg atrazine, 2,4-D, malathion) on Mn oxides (eg birnessite, cryptomelane, pyrolusite).
• Study of Cd adsorption on smectite
• Mineral resources of the Urals, development and environmental impacts
• Chronic pollution from smelter emissions in the town of Zlatna, Romania

For further information contact:

Dr Eva Valsami-Jones
Tel: +44 (0)20 7942 5321

Fax: +44 (0)20 7942 5537
email