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An environmental scientist by training, Larissa pursued her PhD in environmental chemistry researching the environmental effects of metals released into the environment by coal-fired power stations. She is now a postdoctoral fellow in the School of Culture, History and Language in the Archaeology and Natural History program researching the application of geochemistry to track historical environmental changes.
Last year Larissa was awarded a DECRA (Discovery Early Career Researcher Award). Her motivation to propose this DECRA was the need to fill in the gap in knowledge of the historical sources and cycle of mercury in Australia.
'Over the last two decades, mercury studies have received significant support in the Northern Hemisphere due to its toxicity and potential for bioaccumulation. My DECRA project is intended to fill the significant knowledge gap that exists in our geographic region. Knowing the historical changes in mercury emissions and atmospheric fluxes in Australia is the first step to protect human health and the environment from the adverse effects of mercury,' she says.
Though mercury occurs naturally in the environment, mercury researchers, like Larissa, are concerned about the increase in mercury emissions to the environment by human activities.
'Even remote areas have had an increase in mercury atmospheric fluxes and deposition in the environment,' she says. 'This is because the mercury cycle is very dynamic and it connects the entire world. Mercury that is emitted in one part of the world can eventually be transported to any other location and remote areas.
'For example, mercury concentrations in the Arctic region have increased three-fold since the advent of the Industrial Revolution. This is an environmental issue that requires international collaboration and Australia should be supporting this global cause,' emphasises Larissa.
During her postdoctoral research at the CHL, Larissa has acquired important research skills. 'Since I started working in the Archaeology and Natural History at the School of Culture, History and Language I realised I could expand my research far back in time by investigating historical lake sediments. There is a lot of history hidden in sediment cores. We collect the sediments using a core sampler, it's like a metal tube and we put in down into the lake, hammer the pole into the lake bed, where the sampler creates a vacuum that lets us remove the sample from the bed.
Through research of sediments deposited over thousands of years, Larissa is able to understand the natural geochemical cycle of mercury and other elements and establish a baseline against which she compares current data. 'I establish the timeframe of the samples first by using dating analysis. Then you can pinpoint where in the core the time you are interested in is represented. So you might want to see what happened when the power station was established, or you might want to look at the last ice age'.
Historically, mercury has been used very widely in Australia, for example, in gold mining and in agriculture. 'Although Australia has ended such uses, contamination remains in the environment and requires ongoing monitoring and mitigation plans. The main contemporary source of mercury contamination in Australia is the emission of coal-fired power stations due to mercury traces in the coal which are released as it is burnt.'
'This work is timely and important given that international Minamata Convention on Mercury came into force in August, 2017, and that Australia, although a signatory, has done very little to address how it would comply with its obligations if, as anticipated, we ratify the Convention,' warns Larissa. The Minamata Convention on Mercury has been established as an international treaty to protect human health and the environment from the adverse effects of mercury. It commits countries to the reduction of mercury emissions.
The information from Larissa's DECRA will support policy advice to governments, national, state and territory, on appropriate regulations and governance in order to meet Australia's anticipated international commitments to reduce mercury emissions under the recently activated Minamata Convention.