To: The Honorable MayorFrom:
Date: April 19, 2013
Per your request for information regarding the recently published Gladstone Study, I have summarized the important information for your review. The Gladstone Study by Kennedy, Bentley, Heffernan, Paxman, Stevenson & Mueller (2010) examines the potential of a cumulative impact of hazardous air pollutants (HAPs) from industrialization. Specifically, the study examined polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo‐p‐dioxins and furans (PCDD/Fs) over a twelve month period between February, 2009 and January, 2010. The monitoring included utilizing up to six sites for air monitoring during this period.
The community of Gladstone houses a significant number of industrial complexes. Due to the presence of these, there have been concerns regarding the cumulative air impact of HAPs in the area. Specifically, the community expressed concerning regarding the possible risk of chronic exposure to these HAPs. The Parliamentary Member for Gladstone requested incidence of asthma, miscarriage, and cancer for the community.
The health risks associated with PAHs include possible cancer development. PAHs are recognized as carcinogenic and mutagenic, indicating they may cause mutation of an individual’s DNA. The risks of chronic exposure include damage to the lungs, gastrointestinal tract and kidneys. Many of the studies indicating that PAHs may cause cancer were done on animal models (ATSDR, 2008). PCBs have been shown to cause a number of adverse health effects in humans. PCBs are considered probable human carcinogens. They also cause adverse effects on the immune system, nervous system, endocrine system and reproductive system (EPA, 2013). PCDD/F exposure also causes possible negative health effects for humans. These two toxicants, which include forms of dioxin, tend to occur together. Dioxins are well known for their toxicity. This group of chemicals tends to bioaccumulate in humans and the environment. Bioaccumulation occurs when the chemical cannot be eliminated at a rate equal to its absorption. Dioxin is stored in fat cells impeding the quick elimination of the chemical. The short-term exposure to dioxins may cause skin lesions including chloracne and dark patches on the skin. Dioxins may also negatively affect the functioning of the liver. Chronic exposure impairs the immune system, the reproductive system, the endocrine system and the nervous system. Dioxins often mimic hormones in the body, resulting in hormonal disruption. Because dioxins are ubiquitous in the environment, all individuals have a background exposure to them (WHO, 2010).
The Gladstone Study was part of the Clean and Healthy Air for Gladstone (CHAG) project. It was undertaken to examine the levels of these chemicals in the community. It also wanted to study the potential need to relocate the air monitoring stations in the area. It would also compare the levels of HAPs in the area with other areas of Australia.
The key findings of the study indicated that the level of benzo[a]pyrene (B[a]P) determined that the levels measured in Gladstone were consistent with other areas of Australia. B[a]P is used to determine the level of PAHs in the atmosphere. The level of B[a]P also was significantly lower than the levels measured in urban areas, such as Brisbane. The levels of PCDD/Fs also measured were consistent with other background areas of Australia. Furthermore, the levels in the background atmosphere are very low by worldwide standards. Dioxin levels have been extensively monitored in Australia through the National Dioxins Program. Furthermore, octachlorodibenzo-p-dioxin (OCDD) was the congener found in the highest concentrations. Congeners are related chemicals. This particular congener of dioxin is approximately 10,000 times less toxic than the dioxin congener used for standard reference.
While the citizens and representatives of the Gladstone area express concern regarding the potential for air pollution in the area, the risk assessment indicates that this is unfounded. Obviously, individuals have a legitimate right to question the effects of industrialization on their health and well-being. However, despite the heavy industrialization in the area, the data collected indicates that the air possesses no more a significant risk to health outcomes than any other area of Australia. Furthermore, the levels of some HAPs in the air, such as dioxin, are far below the safe limits. The levels of dioxin are consistent with background levels normally found. The detected levels also measured significantly lower than levels measured worldwide.
Based upon the data collected, the levels detected do not pose an acute or chronic risk to the health and well-being of the citizens of Gladstone. It is recommended that the monitoring of the HAP levels continue as a surveillance technique. Furthermore, the introduction of additional factories and industrialization may negatively impact the quality of the air in Gladstone. Due to this, the further addition of industries that pollute should be considered cautiously. All industries are encouraged to reduce their contribution to air pollution as a means to reduce the potential for adverse health and environmental outcomes.
While the study does not indicate an immediate danger from the industrialization, further studies may be warranted. Longitudinal studies may possess a benefit in determining the incidence and prevalence of respiratory, cardiac, and reproductive health outcomes. Studies may also examine the incidence and prevalence of cancer in the inhabitants of the area relative to other areas of Australia with both greater and lower levels of air pollution.
No conclusions may be drawn on the overall level of particulate matter in the atmosphere in the Gladstone area. Particulate matter, specifically ultrafine particulate matter, has been shown to have negative health outcomes for both the respiratory and the cardiac systems. Exposure to high levels of particulate matter leads to increased airway resistance and inflammation in those with asthma (Richards, 2008, pp. 244-46). For this reason, further studies to monitor the levels of particulate matter may elucidate the incidence, prevalence and severity of asthma in the Gladstone community.
- Agency for Toxic Substances and Disease Registry (2008, June) Polycyclic aromatic hydrocarbons (PAHs). What health effects are associated with PAH exposure? Retrieved April 18, 2013, from: http://www.atsdr.cdc.gov/csem/csem.asp?csem=13&po=11
- Environmental Protection Agency (2013, January) Health effects of PCBs. Retrieved April 18, 2013, from: http://www.epa.gov/osw/hazard/tsd/pcbs/pubs/effects.htm
- Kennedy, K., Bentley, C., Heffernan, A., Paxman, C., Stevenson, G., Mueller, J. Gladstone Air Study 2009 –2010: Monitoring for polycyclic aromatic hydrocarbons (PAHs), and polychlorinated dibenzo‐p‐dioxins(PCDDs) &‐furans (PCDFs) and polychlorinated biphenyls (PCBs). The National Research Centre for Environmental Toxicology (Entox), The University of Queensland.
- Richards, I. (2008) Principles and practice of toxicology in public health. Boston: Jones and Bartlett.
- World Health Organization (2010, May) Dioxins and their effects on human health. Retrieved April 18, 2013, from: http://www.who.int/mediacentre/factsheets/fs225/en/