UTS student solves pollution mystery

Research at the University of Technology, Sydney, is helping scientists understand why some waterways remain mostly unpolluted despite being pumped with sewage and industrial and agricultural waste.

UTS Doctoral student in Environmental Sciences, Surattana Settacharnwit, who comes from Thailand, has spent two years studying the water quality of Nong Han, a shallow fresh-water lake in north-eastern Thailand.

Despite raw sewage, agricultural run-off and dog abattoir waste being discharged into Nong Han, the lake has remained relatively pristine. It provides drinking water of an adequate quality, its hatcheries supply healthy fish for sale in local markets, and the non-toxic lake is used as a recreational resource for the local population.

Associate Professor Rod Buckney, who has co-supervised the research, said the lake should be a green soup, given the presence of high levels of nutrients in the water that normally promote the growth of blue-green algae.

"We were puzzled by the lake's remarkable ability to remain relatively pristine and clear, despite daily additions of pollutants," Prof. Buckney said. "We were eager to discover and understand the processes by which the lake's water stays so clean."

The research focused on the role of the abundant aquatic plants covering vast areas of the lake's surface and their ability to control the movement of the nutrient phosphorus to and from the surface sediment of the lake.

"In regard to the plant life in the lake, Surattana has established that the journey of phosphorus between the sediment and the water in Nong Han is occurring very quickly," Prof. Buckney said. "What was once assumed to take weeks or even months is actually happening in only a matter of hours.

"With this new knowledge, researchers can now focus on achieving better biological water purification systems both in Australia and overseas."

Surattana's research has been supported by a Thai Government scholarship.

Item provided courtesy of UTS