Is your water safe?
Friday, 26 October 2012
The Portable Digital Voltammeter used to test arsenic levels
A researcher at Edith Cowan University (ECU) has developed a relatively simple, highly accurate infield method to test the quality of water for toxic metals, such as arsenic and lead, using a portable digital voltammeter.
Chemistry lecturer, Dr Magdalena Wajrak said other accurate methods for detecting these toxic ions are laboratory based and considerably more expensive, requiring sophisticated infrastructure.
The technique developed by Dr Wajrak is considerably cheaper, easier to use and can provide results at the water source.
“This work has contributed in helping people in countries such as Bangladesh, where it is necessary to constantly monitor arsenic levels in groundwater, to reduce people’s exposure to high levels of arsenic,” Dr Wajrak said.
“The test has already been used by the Department of Environment to detect arsenic in groundwater samples in some areas around Perth, where acid sulphate soils are present.”
It works by placing a specific electrode (e.g. gold for arsenic or glassy carbon for lead) into a small amount of water samples and changing the potential at the electrode to deposit the ionic species onto the electrode. The device then strips them back into the water sample, measuring the current being produced, which gives a concentration reading.
Building on the success of this initial project Dr Wajrak has been the recipient of five Category One research grants from Australian Nuclear Science and Technology Organisation (ANSTO), resulting in $59,300 of funding.
These grants have enabled her to carry out specific investigations of the surface of the gold working electrode used in the detection of arsenic in order to further improve detection sensitivity.
“If better understanding of the factors such as working electrode surface, which affects electrochemical process can be obtained, then improvements can be made to the voltametric method to increase its accuracy for arsenic detection,” Dr Wajrak said.
“There is also the potential for this technique to be used to detect other ions in more complicated matrices, such as barium in gunshot residues.”
“Understanding what happens at the electrode surface is crucial in being able to improve sensitivity and reliability of the voltametric method,” Dr Wajrak said.
Dr Wajrak often travels to Sydney (ANSTO) and Melbourne (Australian Synchrotron) to utilise specialised equipment to aide her in this research.
“This research involves the use of highly sophisticated instruments such as scanning electron microscope (SEM), secondary ion mass spectrometer (SIMS) and synchrotron radiation,” said Dr Wajrak.