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Mercury species in environmental samples studied by spectroscopic methods

Qian, Jin (2001). Mercury species in environmental samples studied by spectroscopic methods. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Silvestria, 1401-6230 ; 202
ISBN 91-576-6085-9
[Doctoral thesis]

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Abstract

In this thesis, attention is focused on the determination, stability, reaction, and chemical association of mercury species in various types of environmental samples. Capillary gas chromatography (GC) was coupled to a number of systems for mercury speciation analyses, including microwave-induced plasma atomic emission spectrometry (MIP-AES), inductively coupled plasma-mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS) and mass spectrometry (MS). In addition, synchrotron-based mercury L,-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, sulphur K-edge X-ray absorption near edge structure (XANES) spectroscopy were used to explore the chemical association of monomethyl mercury (CH,Hg (11)) in soil organic matter (SOM). Reactions of mercury species in organic solutions were investigated to determine the stability of mercury species in hydrocarbon products, standards and reference materials. A simple and rapid sample preparation procedure including acid leaching and simultaneous ultrasonic- assisted in situ ethylation and extraction was developed for the determination of methyl mercury in biological samples. The efficiency of different solvent extraction and derivatisation methods for the determination of methyl mercury in soils was evaluated. It was found that the binding affmity of Cu2+ to SOM functional groups and affinity of Br- for mercury ions are strong enough to extract in average 93% of the total mercury in the soil samples investigated. The results indicated that the extraction efficiency was related to the oxidation state of sulphur present in the soil. Reactions with Grignard reagent for the derivatisation of mercury species for GC separation were characterised. Evaluation of derivatisation efficiency and species trans- formation reactions allowed for efficient optimisation of methods to reduce analytical errors. EXAFS analysis provided direct molecular level evidence for the bonding between mercury (in CH,Hg (11)) and sulphur in the first shell at a CH,Hg (II)/Org-Sm, ratio below 0.26 in SOM. Calculated surface complexation constants were in the range of 10163-10167, that was very similar to stability constants for associations between methyl mercury and thiol groups (RSH) in well-defined organic compounds. Concentrations of CH,Hg (11), Hg-tot and sulphur species were determined in soil, soil solutions and streams of a forested catchment. Higher ratios of CH,Hg (II)/Hg-tot were found in stream bank soils and open mire peat soils, indicating that these sites provide favourable conditions for net methylation on a landscape level. Org-SRED made up 50 to 78% of total S in all soil and stream organic samples examined. Model calculations showed that under oxic and slightly reduced conditions nearly all the Hg (11) and CH3Hg (11) were complexed by Org-S,, in soil, soil solution and stream wate

Authors/Creators:Qian, Jin
Title:Mercury species in environmental samples studied by spectroscopic methods
Year of publishing :January 2001
Volume:202
Number of Pages:34
Papers/manuscripts:
NumberReferences
ALLI. Snell, J., J. Qian, M. Johansson, K. Smit and W. Frech. 1998. Stability and reactions of mercury species in organic solution. Analyst 123,905-909. II. Tu, Q., J. Qian and W. Frech. 2000. Rapid determination of methylmercury in biological materials by GC-MIP-AES or GC-ICP-MS following simul- taneous ultrasonic-assisted in situ ethylation and solvent extraction. Journal ofAtomic Absorption Spectrometry 15, 1583-1588. III. Qian, J., U. Skyllberg, Q. Tu, W. F. Bleam and W. Frech. 2000. Efficiency of solvent extraction methods for the determination of methyl mercury in forest soils. Fresenius Journal of Analytical Chemistry 367,467-473. IV. Emteborg, H., J. Snell, J. Qian and W. Frech. 1999. Sources of systematic errors in mercury speciation using Grignard reagents and capillary gas chromatography coupled to atomic spectrometry. Chemosphere 39,1137- 1 152. V. Qian, J., U. Skyllberg, W. Frech, W. F. Bleam, P. R. Bloom and P.-E. Petit. Binding of methyl mercury to reduced sulphur groups in soil organic matter as determined by X-ray absorption spectroscopy and binding affinity studies. (Manuscript .) VI. Qian, J., U. Skyllberg, W. Frech, K. Xia and W. F. Bleam. Distribution of mercury and organic sulphur species in soil, soil solution and stream of a forested catchment. (Manuscript.
Place of Publication:Umeå
ISBN for printed version:91-576-6085-9
ISSN:1401-6230
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P33 Soil chemistry and physics
Subjects:Not in use, please see Agris categories
Agrovoc terms:mercury, gas chromatography, mass spectrometry, x ray spectroscopy, soil solution, soil organic matter
Keywords:biological samples, derivatisation, EXAFS, GC-AAS, GC-ICP-MS, GC-MIP-AES, GC-MS, mercury species, methyl mercury, organic solution, soil solution, SOM, stream water, XANES
ID Code:30
Department:(S) > Institutionen för skogsekologi (930701-061231)
Deposited By: Staff Epsilon
Deposited On:02 May 2002 00:00
Metadata Last Modified:02 Dec 2014 10:01

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