PhD conferred: 2011
It seems that Rachael Smith has been mucking about in stormwater for the past decade. After completing an Environmental Biology degree at UTS Rachael’s Honours project on stormwater convinced her that more laboratory research was needed to investigate using chlorophyll a- fluorescence as a valuable field tool in water quality testing.
“There are some very nasty herbicides and we know they pose a danger to both humans and the environment. Local councils often don’t have the resources to test beyond the basic water quality parameters of heavy metals, nitrates and phosphates and microbiological indicator organisms like e.coli.,” said Rachael.
One drawback of current chemical analysis is the need to know what you’re testing to begin with in order to use the most sensitive methods and equipment. If a screening tool could be used to identify a suite of different pollutants up front this would significantly reduce costs, because you don’t have to test clean samples, and reduce the risk of false positives and negatives.
Rachael’s research has been predominantly laboratory based. After culturing microalgae she exposed them to seven different herbicides encompassing 13 photosynthetic impact sites. Using a special fluorimeter, called an Imaging PAM, changes in fluorescence were measured which indicated the toxicant impact at the specific photosynthetic site. By taking a holistic approach Rachael then incorporated reaction rates, changes in parameters of fluorescence and changes associated with concentration response to create a unique fingerprint or biomarker for each herbicide.
“The Imaging PAM has really opened up a lot more opportunities to do larger experiments. Water testing requires lots of samples and the Imaging PAM does 36 samples at a time compared with two samples in earlier PAMs, “ said Rachael.
Rachael is now in the final stages of writing up her thesis. Preliminary results indicate that individual herbicides can be identified from the laboratory samples.
“I hope someone will be able to expand on this research and use the techniques to identify pollutant mixtures in environmental samples. Anything that impacts on photosynthesis - petrochemicals, pesticides, herbicides, organic pollutants - can be detected and identified. In Europe they are starting to go down this path of using biomarkers in water monitoring. They are protecting the environment by identifying the toxicant rather than its toxicity,” she said.
Rachael would like to continue her career in water pollution and perhaps work in developing countries where there is a great need for water monitoring and education about agricultural runoff and ecotoxicology. She believes that the PhD process has left her with an invaluable set of tools and transferable skills.
“ I’ve learnt a lot about project management and experimental design. You need to be open- minded beyond your core discipline and be creative on a tight budget. I’ve really enjoyed the interaction with colleagues, the problem solving and brainstorming sessions. It has also been great to liase with local councils and get a different point of view," she said.
Rachael is supervised by C3 Director Associate Professor Peter Ralph and Professor Jochen Muller, University of Queensland.
By: Marea Martlew
Email contact: Peter.Ralph@uts.edu.au