Date of Award

2016

Degree Type

Thesis

Degree Name

Doctor of Philosophy

School

School of Medical and Health Sciences

First Advisor

Associate Professor Jacques Oosthuizen

Second Advisor

Professor Wei Wang

Third Advisor

Dr Martyn Cross

Abstract

It has been well established that air pollution is associated with health impacts. This study investigated the relationship between exposure to air pollutants and potential biomarkers of health effects. The research project was conducted in 2 separate study locations and cohorts.

Study 1: An Evaluation of Children’s Exposures to Respirable Particulates, Environmental PM2.5, PAHs and Metal Compounds in The South West of Western Australia. A cross sectional study to evaluate the exposures of children (n=18), and controls (n=15) to respirable particulates PAHs and metal compounds in the South West of Australia during 2011. Ambient particulate matter (PM2.5) samples were found to be significantly higher in Collie as compared to Dalyellup. However, personal PM2.5 concentrations between locations were not significantly different and both PAH and heavy metals were below the levels of detection. Urinary levels of 1-hydroxypyrene (1-OHpy) were below the level of detection. Copper, selenium and nickel were present in urine samples and these were not significantly different between locations, nor was there any correlation with residential areas within study locations. Urinary nickel concentrations were higher than expected for nonoccupational cohorts and although statistically insignificant, mean values of urinary nickel were highest for homes using gas as a fuel source.

These data endorse current views that the reconstruction of PM2.5 exposures and related respiratory health effects based simply on the mass of airborne particulate matter alone is not sufficient in providing an insight to the respiratory health of susceptible subgroups such as children. The presence of certain urinary heavy metals suggests possible accumulation in participants via alternative routes of entry, probably a dietary source. Studies that rely purely on data accrued from ambient PM2.5 mass, and/or general health data might not detect or underestimate significant relationships between certain components of PM2.5.

Study 2: Urinary levels of malondialdehyde and 8-deoxyguanosine as biomarkers of oxidative DNA damage induced by exposure to nickel and cobalt in metal refinery workers. Metal mining and refinery workers in Australia have the potential to be occupationally exposed to quantities of heavy metals that may be associated with health impacts affecting major organ and immune systems. Current regulatory and internal company policies and guidelines require regular monitoring of occupational exposures of employees through a combination of air borne sampling as well as biological monitoring for heavy metals.

Toxic levels of heavy metals accumulated in the body have been shown to elicit inflammatory responses linked to exacerbated health effects impacting the respiratory, cardiovascular and nervous systems. There are many studies that have established a significant link between heavy metal exposure and increased oxidative stress. In light of these observations, this study investigated urinary levels of nickel (Ni) and cobalt (Co) and Malondialdehyde (MDA) and 8-hydroxy-2’deoxyguanosine (8-OHdG) which are oxidative stress markers indicative of cellular and DNA damage.

A positive correlation between urinary Ni and Co exposure and oxidative stress markers among refinery workers was established. This finding has implications for occupational health management as individual responses to exposures can now be identified. In addition to implementing a global mean air borne exposure standard, individual variation and sensitivity can be accommodated through the use of urinary oxidative stress markers

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