Biomarkers for carbon monoxide and benzene in outdoor and indoor microenvironments in South Wales

Henderson, Katrina A. 2008. Biomarkers for carbon monoxide and benzene in outdoor and indoor microenvironments in South Wales. PhD Thesis, Cardiff University.

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Abstract

A messenger role for carbon monoxide has been identified for the cardiovascular system and also possibly for neurological effects through activation of soluble guanylate cyclise (SGC) and consequent production of intracellular cyclic guanosine monophosphate (cGMP). Chronic exposure to carbon monoxide associated with indoor heating may affect this important mechanism. Therefore the differential effects upon cGMP in blood platelets for people residing in homes with different types of heating were investigated. A differential in ambient concentrations of benzene and nitrogen dioxide has also been hypothesized for residential areas of differing urbanicity in particular with respect to traffic flows. Therefore the differential in urinary biomarker of benzene exposure, s phenylmercaptuirc acid (sPMA) as well as in environmental concentrations of nitrogen dioxide was investigated in people residing in urban and less urban microenvironments. Environmental concentrations of carbon monoxide indoors were measured in real-time over a period of one week and integrated measurements of benzene and nitrogen dioxide concentrations outdoors were obtained over a period of one month. cGMP was measured in the blood platelets of subjects and sPMA in their urine. Environmental concentrations of carbon monoxide indoors were low but despite this in homes heated by liquid petroleum gas (LPG) the concentration of cGMP in subjects' blood platelets were twice those in subjects using other types of heating. Further, for the LPG group the difference between paired measurements for the winter and summer seasons were 91%. Substantial differences between mean concentrations of benzene (37%) and nitrogen dioxide (65%) were observed between urban and less urban areas but this differential was not reflected by any difference in toxic uptake as measured by sPMA in urine. Exposure to emissions from LPG heating substantially affected cGMP concentrations in blood platelets but this is very unlikely to be caused by the low levels of carbon monoxide measured. We hypothesize that Nitric oxide may be responsible for the differences observed in cGMP. Substantial differences in outdoor benzene and nitrogen dioxide concentrations exist within the city of Cardiff but sPMA is not sufficiently sensitive to be used as a biomarker of exposure.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Medicine
ISBN:	9781303184727
Date of First Compliant Deposit:	30 March 2016
Last Modified:	10 Jan 2018 02:43
URI:	https://orca.cardiff.ac.uk/id/eprint/55775

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