Biomonitoring of polycyclic aromatic hydrocarbons exposure in small groups of residents in Brisbane, Australia and Hanoi, Vietnam, and those travelling between the two cities
Introduction
Polycyclic aromatic hydrocarbons (PAHs), a class of hazardous air pollutants, are predominantly produced during the incomplete combustion of organic materials, e.g. fossil fuel, coal, and wood. PAHs are widely distributed in the atmosphere and they can be transported over long distances before depositing through atmospheric precipitation onto soils, vegetation or waters (Ravindra et␣al., 2008).
Exposure to PAHs is associated with a variety of health effects including lung, skin and bladder cancers in humans (Agudo, 2006, IARC, 2010, Kim et␣al., 2013). Recent findings are suggestive of relationships between PAHs in placenta and the risk of neural tube defects and the alteration of the immune system (Langlois et␣al., 2012, Walker et␣al., 2013). Other study suggests that exposure to polycyclic aromatic hydrocarbons encountered in New York City air may play a role in childhood Attention Deficit Hyperactivity Disorder behaviour problems (Perera et␣al., 2014).
Due to the ubiquitous presence of PAHs in the atmosphere, exposure to atmospheric PAHs may likely impact large populations; as a consequence, it could be a major public health issue. This is especially important in developing countries, where severe air pollution from fossil fuel combustion, e.g. coal burning power plants and motor vehicles (Gurjar et␣al., 2010, Han and Naeher, 2006), usually exceeds air quality standards (Hopke et␣al., 2008). For example Vietnam ranked among the ten worst countries in the world in terms of air pollution (Emerson et␣al., 2012), with traffic emissions responsible for 70% of all urban air pollution (MoNRE, 2007). One study reported that atmospheric PAHs concentrations at 10 different roadside sites in Hanoi were significantly higher than those from other countries, and often exceeded the recommended maximum thresholds set by the World Health Organisation (Kishida et␣al., 2008). At the same time, developed countries like Australia are considered relatively clean in terms of air pollution with levels of atmospheric PAHs similar to other countries in Europe (Berko, 1999). Levels of atmospheric PAHs in Brisbane, a metropolitan city in Australia, have decreased throughout the last decade (Kennedy et␣al., 2010, Muller et␣al., 1998, Wang et␣al., 2013) probably due to strict emission regulations (Hopke et␣al., 2008).
To study the actual exposure to PAHs, urinary mono-hydroxylated PAHs (OH-PAHs), a group of PAH metabolites, have been used as biomarkers (Jacob and Seidel, 2002). Among the OH-PAHs, 1-hydroxypyrene (1-PYR) is the most commonly used PAH biomarker in both occupational as well as in the general population from various countries (Hansen et␣al., 2008). The use of PAH metabolites as biomarkers is more important when one wants to access the actual change in human exposure to different levels of PAHs (e.g. in different level of air pollution).
However, to our knowledge, there is no study to date using PAH metabolites to assess general human exposure to PAHs in Australia. There are only two known studies in Vietnam assessing PAH exposure by biomonitoring urinary OH-PAHs. One study systematically monitored 1-PYR urinary concentrations in 44 street workers in Hanoi over 4 weeks and consistently showed concentrations of 1-PYR up to 24 times higher than those in the US population. The study suggested substantially higher exposure to PAHs in Hanoi even when the workers wore activated carbon respirators to reduce exposure to PAHs and other air pollutants (Wertheim et␣al., 2012). The other study only analysed random spot urine samples of 23 middle-age people in Hanoi to compare the levels with those from other countries in Asia (Guo et␣al., 2013).
In this study, we report urinary concentrations of PAH metabolites in a small group of residents in Brisbane, Australia, and Hanoi, Vietnam, and those travelling between the two cities. Our goals were to assess (a) the exposure to PAHs in the two cities through biomonitoring of urinary OH-PAH concentrations; (b) the change of OH-PAH profile when people travelled between the two cities; and (c) the influence of age on the concentrations of OH-PAHs.
Section snippets
Study participants
We recruited 16 healthy volunteers (9 adults and 7 children) representing 5 families (Table␣1). Three families lived in metropolitan Brisbane and two families lived in metropolitan Hanoi. Their homes were not close to any heavy emission source or heavy traffic (at least 1 km away from heavy traffic). During the study, one family in Brisbane (two adults and two children) travelled to Hanoi, and then back to Brisbane. All participants were of Vietnamese origin, i.e. there was no race difference
Concentrations of OH-PAHs in the participants’ urine
OH-PAHs concentrations were detectable in most urine samples, with a detection rate over 99% for all nine OH-PAHs. There were 11 samples in which one of the OH-PAHs concentrations was below the LOD. Values <LOD were replaced as LOD/squrt(2) in the statistical analysis (Hornung and Reed, 1990).
OH-PAHs urinary concentrations in samples collected in Hanoi and Brisbane are compared in Table␣2 and stratified into two age groups (children and adults). Median unadjusted concentrations of the nine
Discussion
This is the first study to monitor the biological response on urinary PAH biomarkers to the change in atmospheric PAH exposure for small groups of adults and children in a non-occupational setting while maintaining a similar diet. It is also the first study, to the best of our knowledge, which reports urinary OH-PAHs levels in a small group of residents living in Australia.
Conclusion
This is the first study, to the best of our knowledge, reporting levels of urinary OH-PAHs in Brisbane, Australia. Even with a small sample size, we found that the urinary OH-PAH levels in Brisbane were consistent with those in developed countries. We found 2–10 times higher levels in residents in Hanoi, Vietnam than those in Brisbane suggesting that PAH exposure in Hanoi was substantially higher than in Brisbane, most likely because of the higher ambient air PAH concentrations. Travelling from
Acknowledgements
We would like to thank the participants for their time and devotion. The co-authors of this manuscript do not have any financial conflict of interest. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. PT is partly funded by a UQ Postdoctoral Fellowship. JFM is funded by an ARC Future Fellowship (FT120100546). Entox is a joint venture of the University of Queensland and
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