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Title: Determination and speciation of mercury in sediment and related samples from Greece and Scotland
Author: Cavoura, Olga
ISNI:       0000 0004 5359 1625
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2014
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Mercury is a global pollutant. Research is needed to improve methods for Hg detection and improve understanding of its biogeochemical cycle and risks to human health. In this study, a simple, colorimetric method utilising the reaction of Hg with copper(I)iodide was characterised and adapted for screening marine samples, and the speciation and relationships of Hg with other sediment parameters in contaminated environments was examined. Field application of the colorimetric method indicated Hg concentrations in sediments from West Scotland, U.K., and Kifissos River, Greece, were below Canadian sediment quality guideline values of 0.13 and 0.17 mg/kg for marine and freshwater sediment respectively, whereas sediment from the Falkirk area of the Union Canal, U.K., and Elefsina Bay, Greece, had Hg concentrations above probable effect levels (0.49 and 0.7 mg/kg). Total sediment Hg concentrations, determined quantitatively using cold-vapour atomic absorption spectrometry (AAS), ranged from 0.220 to 2.96 mg/kg in Elefsina Bay. Concentration was influenced by proximity to nearshore pollution sources but was not found to vary seasonally or be related to sediment organic matter content. Sequential extraction indicated that Hg speciation - hence mobility - varied between sites. No Hg was detected in the fish Mugil Cephalus indicating no threat to humans from consumption. Total sediment Hg concentrations in the Union Canal ranged from 22 to 1200 mg/kg. Both sequential extraction and speciation analysis using thermodesorption AAS indicated that ca.>70% of the Hg present was mobile. Analysis by gas chromatography inductively coupled plasma mass spectrometry showed that the methylmercury content was <0.03% of the total Hg content. A negative relationship was found between total Hg concentration and % methylmercury (r² = 0.60). Ethylmercury was detected in the samples and weak positive relationships determined between methylmercury and ethylmercury and organic matter content, while low pH appeared to favoured the partitioning of methylmercury into the water column.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available