River of gold

A recent UWA media release highlights research recently published on the measurement of gold and other metals in the water of Perth’s iconic Swan River estuary. Dr Andy Lucas, who did the work as part of his PhD, is lead author for the article in Geochimica et Cosmochimica Acta with contributions from his supervisors Andrew Rate and Ursula Salmon, and WA Department of Water collaborators Kieryn Kilminster and Sarah Larsen.

A key finding of the research was that concentrations of gold and several other trace elements in Swan River water were higher at sites downstream in the Perth metropolitan area. The techniques for measurement of gold in water, developed by an international team assembled by Dr Rate, allowed measurement of both dissolved and nanoparticulate gold, and a surprising finding was the likely existence of gold nanoparticles suspended in estuary water. The technique, an adaptation of diffusive gradients in thin films (DGT), provides highly sensitive, time-averaged measurements of gold in water, and is not subject to fluctuations caused by rainfall or tidal flow. Separate “snapshot” measurements of gold in the Swan estuary made alongside DGT measurements showed that gold concentrations could vary by up to 3-fold in 24 hours.

Andy in the lab
Dr Andy Lucas preparing DGT devices for measurement of gold in water
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DGT array
Schematic of the DGT device array used in the research. The outer cage prevents damage from hungry estuarine critters!
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lab testing gold DGT
Setup used to test DGT devices in the lab. Look for the tiny gold nugget!

Andy’s project was conceived with mineral exploration in mind, and the DGT technique has also shown promise as a sensitive method for soil analysis for gold exploration.

The story has been picked up (or at least syndicated) by several news outlets, including an interview on Radio 6PR, and articles on news.com.au, The Daily Telegraph, PerthNow, and the Herald Sun. It’s also covered in an article on the ScienceNetwork WA website.

For more information:

Lucas, A.R., Salmon, S.U., Rate, A.W., Larsen, S., Kilminster, K.L., 2015. Spatial and temporal distribution of Au and other trace elements in an estuary using the diffusive gradients in thin films technique and grab sampling. Geochimica et Cosmochimica Acta doi: http://dx.doi.org/10.1016/j.gca.2015.08.025

Lucas, A.R., Rate, A.W., Salmon, S.U., Reid, N., Anand, R.R., 2013. Evaluating the diffusive gradients in thin films technique for the detection of multi-element anomalies in soils. Explore, 161, 1-15.  http://www.researchgate.net/publication/258521441

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