August 1998 Newsletter

US EXPERIENCE NEXT STEP IN PHD

PhD student Jo Cavanagh is US-bound after winning a bid to undertake advanced training in environmental chemistry and risk assessment.

Jo won a US$10,000 SEATC fellowship which will take her to the Woods Hole Oceanographic Institute, Western Washington University and Harvard University in her quest to develop a risk assessment model for the evaluation of chemical usage in the Queensland sugar industry. She is supported by CRC Reef Research Centre Ltd and is currently based at the Australian Institute of Marine Science.

She sees the US experience as a natural 'next step' in her PhD which is looking at the residues of organochlorine (OCs) pesticides in near-shore environments and their relationship to historical agricultural industries.

"Organochlorine pesticides have historically been widely used by the sugar industry," Jo said. "Although their use has been phased out, concern over their environmental impact still exists due to their persistent nature and the quantity of chemicals used. By understanding the legacy of OCs which can give use a 'worst-case' scenario, we will also increase our understanding of the impact of chemicals that are still currently used".

"It is essential to understand the link between land-based chemical usage and their environmental effect, in order to assess and minimise impact on the adjacent marine environment."

To date Jo's project has involved data collection relating to levels of OCs in cane land soils, sediments in drainage channels leading off farms and marine sediments. Assessment of the biological impact of OCs is being undertaken through examination of enzyme activity in a local fish species. Collection of historical climatic, land-use and pesticide application information to be used in the risk assessment model has also been undertaken.

"Despite known historical usage in adjacent river catchments I have been unable to detect the presence of OC residues in the Herbert and Burdekin River regions of the North Queensland coastal marine environment," she said. "Although I have found low levels of OC residues in cane land soils, it seems that little or none of the pesticides historically used in the sugar industry have reached the marine environment."

However, Jo believes that the development of a risk assessment framework is still important for the sugar industry and the coastal region.

"The risk assessment research will provide a framework that can be applied to many relevant chemical compounds. It can map out how compounds are transported from land to the marine environment and therefore provide a better ability to predict what will happen if pesticide usage continues to increase or changes".

"The other important point to remember is that my work involves sediment-bound contaminants which have the potential to bioaccumulate in animals. Although I am not seeing OCs in the sediments, it doesn't necessarily follow that they have no impact on biological organisms. Again, a risk assessment framework will be useful in helping to predict the fate of OCs and other chemical contaminants." During her four-month stint in the US later this year, Jo will be examining three approaches to risk assessment to gain insight into the strengths, weaknesses and applicability of the different models. "By comparing and evaluating different models, I am hoping to develop an appropriate and effective risk assessment process to the Australian tropical environment," Jo said.

Jo will also be presenting papers at two international conferences after also winning a 1998 Australian Marine Science Association Student Prize. She will be presenting 'Ecological Risk Assessment and the North Queensland Sugar Industry' at the Ecological Risk Assessment and Risk Management Symposium in Washington and 'Environmental and Economic Sustainability of Chemical Usage in the North Queensland Sugar Industry' in the Issues in Environmental Pollution Symposium in Colorado.

Jo said presentation of her results would be of particular interest to international audiences because the research has been undertaken in a tropical environment which has remained in a seemingly pristine state despite intensive land-usage.

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