A world first study into concentrations of gold in urban waterways, and how these change at different locations along the river and over time, has revealed the City of Perth is contributing valuable metals into the Swan River.
Scientists from The University of Western Australia’s School of Earth and Environment used a ground-breaking new technique to measure gold in the Swan River. The method was developed by an international team led by UWA’s Dr Andrew Rate.
The results, scheduled for publication in the journal Geochimica et Cosmochimica Acta, showed that concentrations of gold and several other trace elements in the water were higher at sites downstream of the Perth metropolitan area.
Dr Rate said gold is usually present at extremely low concentrations in natural water although recent continental scale data from Europe on trace elements in soils showed that other major cities are also sources of gold, silver and other metals.
“Our new technique improves on previous methods for measuring gold in river water, because it averages concentrations over time,” Dr Rate said.
“This means that short-term spikes or fluctuations in the concentration of gold and other trace metals are averaged out, improving the reliability of our data,” he said.
Lead author of the study, Dr Andrew Lucas, said the use of the technique ‘Diffuse Gradients in Thin Films’ or DGT had the potential to be used more widely in the environmental and geological sciences.
“We’ve now shown that DGT can measure gold as well as other trace metals in rivers and groundwater and the greater measurement precision means that we should be better able to understand trace element dynamics in estuaries and other natural environments,” Dr Lucas said.
“Additionally, since we are now able to measure gold, DGT also provides a promising new technique for mineral exploration.”
The groundbreaking research formed part of Dr Lucas’s PhD programme, and was funded by the Australian Research Council and Newmont Australia-Pacific.
To view the research published in the Geochimica et Cosmochimica Acta journal article visit https://www.sciencedirect.com/science/article/pii/S0016703715005281 .