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A study of the relationship between arsenic bioaccessibility and its solid phase distribution in Wellingborough soils

Wragg, Joanna. 2005 A study of the relationship between arsenic bioaccessibility and its solid phase distribution in Wellingborough soils. University of Nottingham, Geography, PhD Thesis.

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Abstract/Summary

The aim of this study was to establish the relationship between the measured bioaccessibility and the solid-phase distribution of arsenic in Wellingborough soils. Arsenic is known to be present in soils in the Wellingborough area of Northamptonshire at concentrations up to c. 100 mg kg-1, which is above the soil guideline value of 20 mg kg-1 for this element in residential gardens, with or without plant uptake, and allotments. Four different locations were chosen from around the Wellingborough area as test sites for use in the study, two gardens, a Country Park and a new housing development site. In total 21 samples were collected to represent the ranges of As in the Wellingborough test soils at these locations. To achieve the aim of this study the test soils were chemically characterised using a combination of analytical techniques that included XRFS and mixed acid digestion/ICP-AES, XRD, soil pH, TOC and CEC. The bioaccessible arsenic content of the soils was measured using a physiologically based extraction test (PBET). The physico-chemical distribution of arsenic between the different soil components present was determined using the CISED test and cluster analysis. The majority of total arsenic was found to be held in pure iron oxides but the bioaccessible arsenic was found to be associated with impure iron oxides, clays and carbonate sources. The bioaccessibility of arsenic, for the oral ingestion pathway, in the Wellingborough test soils was shown to be below the SGV of 20 mg kg-1. A strong positive relationship between the total arsenic and iron present in the test soils was identified. The bioaccessible arsenic was shown not to be related to the total arsenic content of the test soils. The bioaccessible arsenic was shown to be derived from soil components derived from iron and non-iron dominated sources and is dependant on the interaction of different soil constituents.

Item Type: Publication - Thesis (PhD)
Programmes: BGS Programmes > Chemical and Biological Hazards
NORA Subject Terms: Earth Sciences
Health
Date made live: 22 Aug 2012 09:23
URI: http://nora.nerc.ac.uk/id/eprint/18928

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