On 5 November 2009 Queensland Health released an Interim Health Risk Assessment (HRA). This interim report was based upon air monitoring data collected up until June 2009 and broadly assessed the risks posed to the Gladstone community by emissions from industrial and other sources.

The final detailed Gladstone HRA is due in mid-2010.This report will be based upon a thorough analysis of the community’s exposure to a comprehensive list of over 160 contaminants of concern.

In future columns I will examine the findings of the Interim HRA. However, today I’ll discuss the fourth and last step to complete a HRA, the health risk assessment.

In this last step, the measured levels of each contaminant are firstly compared to the contaminant’s air quality standard.As discussed in a previous column, these air quality standards apply safety factors of between 1/10th to more than 1/100th to the concentrations thought to have any impact. So these standards are very conservative.

The generally accepted assessment guideline is that if a contaminant exposure concentration is less than 30 per cent of its air quality standard, then this level of exposure is regarded as safe.

If the contaminant exposure is found to be more than 30 per cent of its air quality standard, there is a possibility that this could be unsafe and so Queensland Health conducts further investigation into this contaminant.

For example, over the past 18 months the Clean and Healthy Air for Gladstone project found that on more than 10 occasions particulate pollution (dust) levels were greater than 30 per cent of the Australian and World Health Organisation standards. Investigation of these results found that these readings all coincided with bushfire and dust storms in our local and regional areas.

In summary the interim HRA report found that to date, with the exception of particulate pollution, the concentrations of nearly all contaminants were less than 5 per cent of the contaminant’s air quality standard, with the majority being less than 1 per cent. However, after the final HRA is released, we will be able to draw more confident conclusions about air quality in the Gladstone area.

If you have any questions about the four steps to complete a HRA, please go to our forum topic at www.gilg.com.au.

If you would like to have your say on how GILG is going and don't know how, please click on this link which shows you how to register and make a comment, anonymously if you wish.

I look forward to hearing from you soon, cheers, Kurt.