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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Dealing with contaminated land in the 'New Regime' : an appraisal of the use of plants as biomonitors for metal contamination analysis and risk assessment for a former landfill site in Greenwich

Murphy, Anthony Patrick January 2007 (has links)
In assessing the health risks posed from heavy metals in a contaminated site, it is important to determine when the contamination occurred and when the metals become available to the surrounding biota. Trees and plants growing in the vicinity of a contaminated site may provide such a historic record. There have been few studies on their role as biomarkers to identify metal mobility or bioavailability for continuous monitoring purposes. The aim of the study was to evaluate the role of plants as biomonitors for site characterisation and risk assessment purposes and to see if there was any selectivity between metal uptake in leaves and roots. Tree cores were also collected as metals in soil or ground water and may be drawn up via tree roots and deposited in the growth rings. This was examined using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LAICPMS) and Proton Induced X-Ray Emission (PIXE). From the plant analysis, the elements present in highest amount were lead, zinc and cooper. The mobility of lead could be monitored by bramble and nettle leaves; that of copper by nettle roots and bramble leaves and that of zinc by nettle roots, bramble and sycamore leaves. Analysis of tree cores by LAICPMS and PIXE showed a contrasting contaminant signature between the sampled trees, as there was inconsistency of metal concentrations within the same segment of growth ring. This variability may offer an insight into labile metal function within the tree physiology. The utility of using the dendrochemical record may best serve as an indicator of macro-environmental perturbations, rather than an indicator of labile metal chronologies, for which only lead showed a reasonably consistent decline through time, across the tree core record.

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