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Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote Euglena gracilis.
Ecotoxicology. 2012 May; 21(4):1013-23.E

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.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Trenfield MA
Ecotoxicology Program, Environmental Research Institute of the Supervising Scientist, Darwin, Australia. Melanie.Trenfield@environment.gov.au
Ng JC
No affiliation info available
Noller B
No affiliation info available
Markich SJ
No affiliation info available
van Dam RA
No affiliation info available

MeSH

BenzopyransCarbonChemical PhenomenaEnvironmental MonitoringEuglena gracilisFresh WaterInhibitory Concentration 50Linear ModelsRiversToxicity TestsUraniumWater Pollutants, Radioactive

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22278366

Citation

Trenfield, Melanie A., et al. "Dissolved Organic Carbon Reduces Uranium Toxicity to the Unicellular Eukaryote Euglena Gracilis." Ecotoxicology (London, England), vol. 21, no. 4, 2012, pp. 1013-23.
Trenfield MA, Ng JC, Noller B, et al. Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote Euglena gracilis. Ecotoxicology. 2012;21(4):1013-23.
Trenfield, M. A., Ng, J. C., Noller, B., Markich, S. J., & van Dam, R. A. (2012). Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote Euglena gracilis. Ecotoxicology (London, England), 21(4), 1013-23. https://doi.org/10.1007/s10646-012-0855-x
Trenfield MA, et al. Dissolved Organic Carbon Reduces Uranium Toxicity to the Unicellular Eukaryote Euglena Gracilis. Ecotoxicology. 2012;21(4):1013-23. PubMed PMID: 22278366.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote Euglena gracilis. AU - Trenfield,Melanie A, AU - Ng,Jack C, AU - Noller,Barry, AU - Markich,Scott J, AU - van Dam,Rick A, Y1 - 2012/01/26/ PY - 2012/01/09/accepted PY - 2012/1/27/entrez PY - 2012/1/27/pubmed PY - 2012/9/11/medline SP - 1013 EP - 23 JF - Ecotoxicology (London, England) JO - Ecotoxicology VL - 21 IS - 4 N2 - 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. SN - 1573-3017 UR - https://www.unboundmedicine.com/medline/citation/22278366/Dissolved_organic_carbon_reduces_uranium_toxicity_to_the_unicellular_eukaryote_Euglena_gracilis_ L2 - https://doi.org/10.1007/s10646-012-0855-x DB - PRIME DP - Unbound Medicine ER -