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Toxicity of uranium and copper individually, and in combination, to a tropical freshwater macrophyte (Lemna aequinoctialis)
- Source :
- Chemosphere. 62(8)
- Publication Year :
- 2004
-
Abstract
- Copper (Cu) and uranium (U) are of potential ecotoxicological concern to tropical freshwater biota in northern Australia, as a result of mining activities. Few data are available on the toxicity of U, and no data are available on the toxic interaction of Cu and U, to freshwater biota. This study determined the toxicity of Cu and U individually, and in combination, to a tropical freshwater macrophyte, Lemna aequinoctialis (duckweed), in a synthetic soft water (27°C; pH, 6.5; hardness, 40 mg CaCO3 l-1, alkalinity, 16 mg CaCO3 l-1), typical of many fresh surface waters in coastal northern Australia. The growth rate of L. aequinoctialis decreased with increasing Cu or U concentrations, with the concentration of Cu inhibiting growth by 50% (EC50) being 16 ± 1.0 μg l-1, with a minimum detectable effect concentration (MDEC) of 3.2 μg l-1. The concentration of U inhibiting growth by 50% (EC50) was 758 ± 35 μg l-1 with a MDEC of 112 μg l-1. The EC50 value for the exposure of L. aequinoctialis to equitoxic mixtures of Cu and U was significantly (P ≤ 0.05) higher than one toxic unit (1.35; 95% confidence interval, 1.18-1.52), indicating that the combined effects of Cu and U are less than additive (antagonistic). Therefore, inhibition of the growth rate of L. aequinoctialis was reduced when Cu and U were present in equitoxic mixtures, relative to individual metal exposures. Since non-additive (e.g. antagonistic) interactions of metal mixtures cannot be predicted using current mixture models, these results have important potential implications for the protection of freshwater ecosystems through the derivation of national water quality guidelines. © 2005 Elsevier Ltd. All rights reserved.
- Subjects :
- Environmental Engineering
Health, Toxicology and Mutagenesis
Fresh Water
Aquatic plant
medicine
Environmental Chemistry
Ecotoxicology
Meteorology & Atmospheric Sciences
Animals
Lemna
biology
Copper toxicity
Public Health, Environmental and Occupational Health
Australia
Fishes
General Medicine
General Chemistry
medicine.disease
biology.organism_classification
Pollution
Macrophyte
Drug Combinations
Environmental chemistry
Lemna aequinoctialis
Uranium
Soft water
Phytotoxicity
Environmental Sciences
Copper
Water Pollutants, Chemical
Subjects
Details
- ISSN :
- 00456535
- Volume :
- 62
- Issue :
- 8
- Database :
- OpenAIRE
- Journal :
- Chemosphere
- Accession number :
- edsair.doi.dedup.....4073f5e3057dce257a7e58469b143796