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Using tree rings to track atmospheric mercury pollution in Australia: the legacy of mining in Tasmania
journal contribution
posted on 2023-05-20, 20:50 authored by Schneider, L, Kathryn AllenKathryn Allen, Walker, M, Morgan, C, Haberle, SHistorical records of mercury (Hg) deposition in lake sediments have commonly been used to monitor historic atmospheric concentrations. In the Australian environment, however, freshwater lakes are limited, restricting the region for which depositional archives of Hg can be derived. In this study we show that dendrochemistry can provide a record of atmospheric concentrations at very high resolution. We measured Hg concentrations in growth rings of two tree species from a site in western in Tasmania-Huon Pine (Lagarostrobus franklinii) and Celery Top Pine (Phyllocladus aspleniifolius). This region has been heavily mined over the past 150 years. Although much previous work has linked atmospheric Hg to gold mining, the evidence in this study suggests that copper smelters in Queenstown and Zeehan, not gold mining activities, were the main sources of Hg emissions to the atmosphere in this location. Huon Pine had significantly higher background Hg concentrations (x̄ = 5.62 ng/g) than Celery Top Pine (x̄ = 2.95 ng/g). No significant increase in Hg concentration during the peak copper smelting phase (1896 to 1935) was observed in Celery Top Pine, while a significant 1.4 fold-increase was observed in Huon Pine. Our results show that of species examined across the globe, Huon Pine is one of the most efficient bioaccumulators of Hg, making it a good proxy for tracking historical Hg emissions in western Tasmania. This ability to measure Hg in the environment is essential if Australia ratifies the Minamata Convention.
History
Publication title
Environmental Science and TechnologyVolume
53Issue
10Pagination
5697-5706ISSN
0013-936XDepartment/School
School of Geography, Planning and Spatial SciencesPublisher
Amer Chemical SocPlace of publication
1155 16Th St, Nw, Washington, USA, Dc, 20036Rights statement
Copyright 2019 American Chemical SocietyRepository Status
- Restricted