Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote Euglena gracilis

Trenfield, Melanie A., Ng, Jack C., Noller, Barry, Markich, Scott J. and van Dam, Rick A. (2012) Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote Euglena gracilis. Ecotoxicology, 21 4: 1013-1023. doi:10.1007/s10646-012-0855-x


Author Trenfield, Melanie A.
Ng, Jack C.
Noller, Barry
Markich, Scott J.
van Dam, Rick A.
Title Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote Euglena gracilis
Formatted title
Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote Euglena gracilis
Journal name Ecotoxicology   Check publisher's open access policy
ISSN 0963-9292
1573-3017
Publication date 2012-05
Sub-type Article (original research)
DOI 10.1007/s10646-012-0855-x
Volume 21
Issue 4
Start page 1013
End page 1023
Total pages 11
Place of publication New York, United States
Publisher Springer New York
Collection year 2013
Language eng
Formatted abstract
The influence of dissolved organic carbon (DOC), in the form of Suwannee River fulvic acid (SRFA), on uranium (U) toxicity to the unicellular eukaryote, Euglena gracilis (Z strain), was investigated at pH 6. In a background medium without SRFA, exposure of E. gracilis to 57 μg L -1 U resulted in a 50% reduction in growth (IC 50). The addition of 20 mg L -1 DOC (as SRFA), reduced U toxicity 4 to 5-fold (IC 50 increased to 254 μg L -1 U). This reduction in toxicity was also evident at more sensitive effect levels with a 10% reduction in growth (IC 10) occurring at 5 μg L -1 U in the background medium and at 17 μg L -1 U in the SRFA medium, respectively. This amelioration of toxicity with the addition of SRFA was linked to a decrease in the bioavailability of U, with geochemical speciation modelling predicting 84% of U would be complexed by SRFA. The decrease in bioavailability of U in the presence of SRFA was also evident from the 11-14 fold reduction in the cellular concentration of U compared to that of E. gracilis in the background medium. Stepwise multiple linear regression analyses indicated that UO 2 2+ alone explained 51% of the variation in measured U toxicity to E. gracilis. Preliminary U exposures to E. gracilis in the presence of a reactive oxygen species probe, suggest exposure to ≥60 μg L -1 U may induce oxidative stress, but this endpoint was not considered to be a sensitive biological indicator.
Keyword Euglena
Fulvic acid
Uranium
Toxicity
Freshwater
Dissolved organic carbon
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 7 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 9 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Mon, 21 May 2012, 22:36:33 EST by System User on behalf of National Res Centre For Environmental Toxicology