HR: 0800h
AN: H31D-1325    [Abstracts]
TI: Development And Evaluation Of Rare Earth Element (REE) Labelled Clays As Fine Sediment Transport Tracers In The Freshwater and Marine Environment.
AU: * Suzuki, K
EM: k.suzuki@qmul.ac.uk
AF: Queen Mary, University of London.Centre for Aquatic and Terrestrial Environments, Department of Geography, Department of Geography, Mile End Road, London, E1 4NS United Kingdom
AU: Spencer, K
EM: k.spencer@qmul.ac.uk
AF: Queen Mary, University of London.Centre for Aquatic and Terrestrial Environments, Department of Geography, Department of Geography, Mile End Road, London, E1 4NS United Kingdom
AB: There is an urgent need to develop a field methodology to accurately measure transport pathways of the <63 um sediment fraction in coastal and estuarine environments. As both inorganic and organic contaminants are often associated with fine sediment particulates transportation, measuring the accurate field transport pathways of fine sediments in fresh and marine environment is extremely important step for understanding the fate of environmental contaminants. Techniques such as sediment trend analysis and sediment tracing using fluorescent sands are well established for the silt and sand fraction but are unsuitable for clay sediments due to their cohesive nature. Geochemically labelled clays have been used as fine sediment tracers in freshwater environments with some success, although little is known about their chemical or physical behaviour once released to saline environments. In this work, common clay minerals (biotite, kaolinite, montmorillonite and phlogopite) have been used as the base aggregates for the sorption of REEs (lanthanum, samarium and holmium) to produce geochemical sediment tracers. The tracer element signal must be detectable after considerable dilution and dispersion in both fresh and marine environment and in preliminary experiments a labelled bentonite retained 43000 ug g-1 La reduced to 36000 ug g-1 La after washing in seawater. This element signal can be detected by routinely available ICP techniques and suggests that REE labelled clay minerals may prove to be suitable sediment tracers and require further investigation. In freshwater and marine environments, the tracer elements may be exchanged with competing cations, thus the extent of REE desorption when exposed to freshwater and marine conditions has been investigated over a range of salinities and for a number of clay minerals, these data will also be presented.
DE: 1862 Sediment transport (4558)
DE: 1895 Instruments and techniques: monitoring
DE: 4558 Sediment transport (1862)
SC: Hydrology [H]
MN: Fall Meeting 2005