Toxicity to Australian tropical freshwater species: amelioration by dissolved organic carbon & linking toxicity with intracellular oxidative stress

Trenfield, M., Markich, S., Ng, J., Noller, B. and van Dam, R. U. (2010). Toxicity to Australian tropical freshwater species: amelioration by dissolved organic carbon & linking toxicity with intracellular oxidative stress. In: 31st Annual Meeting in North America of the Society of Environmental Toxicology and Chemistry (SETAC), Portland, Oregon, (115-115). 7-11 November 2010.

Author Trenfield, M.
Markich, S.
Ng, J.
Noller, B.
van Dam, R. U.
Title of paper Toxicity to Australian tropical freshwater species: amelioration by dissolved organic carbon & linking toxicity with intracellular oxidative stress
Conference name 31st Annual Meeting in North America of the Society of Environmental Toxicology and Chemistry (SETAC)
Conference location Portland, Oregon
Conference dates 7-11 November 2010
Place of Publication Pensacola, FL, United States
Publisher Society of Environmental Toxicology and Chemistry (SETAC)
Publication Year 2010
Year available 2010
Sub-type Oral presentation
ISSN 1087-8939
Start page 115
End page 115
Total pages 1
Abstract/Summary In Australia, activity in U exploration and mining is growing, and this may result in increased amounts of U being transferred to aquatic ecosystems. The Alligator Rivers Region (ARR) in northern Australia is a historical and current focal point for U exploration and mining. A “high reliability” site-specific guideline value of 6 µg/L U exists for the Magela Creek catchment of this region, based on local species chronic toxicity data. While this guideline incorporates, to some extent, the presence of natural dissolved organic carbon (DOC) as a complexing agent for U, there has been little investigation into the extent that varying concentrations of DOC in natural waters can influence U toxicity. The influence of two DOC sources on the toxicity of U to three Australian tropical freshwater species – the northern trout gudgeon, Mogurnda mogurnda, the green alga, Chlorella sp. and the green hydra, Hydra viridissima has been quantified in this study. The influence of a commercial standard Suwannee River fulvic acid (SRFA) on U toxicity was assessed with the objective that this could be used as a readily available DOC source for metal/DOC toxicity studies. U exposures were conducted in synthetic soft water lacking DOC, supplemented with SRFA at a range of DOC concentrations (0-20 mg/L). U toxicity was up to 20 times less in water containing 20 mg/L DOC, relative to DOC-free test waters. U toxicity was also assessed in natural billabong water containing 10 mg/L DOC, in which U toxicity was up to ten times less, relative to DOC–free test waters. Geochemical speciation modelling confirmed the decreased U toxicity was primarily due to lowering of the free uranyl ion (UO22+) concentration through complexation with DOC. This modelling predicted a similar rate of UO22+-DOC complexation occurred in the presence of each DOC source. Physicochemical characterisation of the fulvic acids revealed striking similarities in their properties, supporting the likelihood of a similar capacity to complex metals. Mechanistic studies exposing the unicellular Euglena gracilis to U in the presence of a reactive oxygen stress probe, indicated inhibition of cell growth and cell death were linked to U-induced oxidative stress.
Subjects 050204 Environmental Impact Assessment
050206 Environmental Monitoring
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Invited abstract, no. 499 Conference theme: 'Bridging Science with Communities'

Document type: Conference Paper
Collection: National Research Centre for Environmental Toxicology Publications
 
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Created: Tue, 15 Mar 2011, 15:16:44 EST by Manjit Sanghera on behalf of National Res Centre For Environmental Toxicology