High mass resolution and mass accuracy spectrometric techniques to explore the contamination relationship between bfrs and brominated/mixed halogenated dioxins and furans

Peters 1982-2019, Leon Isaac (2019). High mass resolution and mass accuracy spectrometric techniques to explore the contamination relationship between bfrs and brominated/mixed halogenated dioxins and furans. University of Birmingham. Ph.D.

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Abstract

Dioxins and furans are classes of toxic, persistent environmental contaminants. These compounds, despite never being deliberately synthesized in any great quantity are present in detectable concentrations in almost every environmental matrix. Brominated and Mixed halogenated dioxins and Furans, unlike their comparatively well studied chlorinated analogues have not received nearly as much scientific attention. Despite having comparable physico-chemical and toxicological properties are as yet are not officially listed as POPs. The lack of available scientific data pertaining to Br and mixed dioxins and furans is due principally to the almost prohibitive expense and analytical difficulty of their analysis. Isobaric interferences with PBDEs, PCBs and PBBs (among others) require extensive clean-up procedures, analysis exclusively by high resolution mass spectrometry, judicious selection of quantification ions and meticulous data interpretation. Also, until only recently have 13C labelled surrogates standards become commercially available. Recent advances in high resolution high accurate mass instrumentation has the potential to overcome many of the analytical challenges presented with the analysis of these compound groups.

Despite limited data, current theory concerning the sources of these compounds in the environment has predominantly centred on their formation by high temperature thermolysis in the presence of PBDEs or other potential halogenated phenolic precursors. While substitutive evidence exists confirming their source commonality, extension of this relationship at points of contamination has yet to be explored rigorously.
Accordingly, to address this knowledge gap and overcome the analytical barriers hampering these research efforts, an appropriately sensitive and selective analytical methodology was developed. This method utilised the recently released and state-of-the-art Thermo Scientific GC Q Exactive mass spectrometer. Its suitability for the analysis of trace organic contaminants including the brominated and mixed halogenated dioxins and furans as well as polybrominated diphenyl ethers was established through the analysis of certified reference standards. This technique further extended to provide for analytical quantification of these compounds in freshwater sediments, human breast milk as well as atmospheric particulate matter.

To address the presence and extent of contamination relationships in these matrices measurements were taken of all target compounds concurrently and concentrations examined for correlations. Contamination trends were generated through the use of radiometrically dated sediment cores and chronologies revealed statistically significant associations between a number of key individual compounds. Measurements of human breast milk confirmed for the first time the presence of brominated furans in UK mothers. Through the analysis of atmospheric particulate matter sampled during a fire event in the city of Santiago, Chile measurements made revealed the presence of elevated concentrations of brominated furans at sites affected by this event as well as congener compositional changes.

The adoption of this development analytical method and its application to relevant environmental and biological matrices the authors hope to reduce the analytical complexity of such measurement for future assessments and alleviate constraints to future assessments of these persistent and toxic environmental pollutants.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):