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Toxicity of uranium and copper individually, and in combination, to a tropical freshwater macrophyte (Lemna aequinoctialis).
Chemosphere. 2006 Mar; 62(8):1224-33.C

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 degrees 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 microg l-1, with a minimum detectable effect concentration (MDEC) of 3.2 microg l-1. The concentration of U inhibiting growth by 50% (EC50) was 758+/-35 microg l-1 with a MDEC of 112 microg l-1. The EC50 value for the exposure of L. aequinoctialis to equitoxic mixtures of Cu and U was significantly (P0.05) 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.

Authors+Show Affiliations

Charles AL
Environment Division, Australian Nuclear Science and Technology Organization, Private Mail Bag 1, Menai, NSW 2234, Australia.
Markich SJ
No affiliation info available
Ralph P
No affiliation info available

MeSH

AnimalsAustraliaCopperDrug CombinationsFishesFresh WaterUraniumWater Pollutants, Chemical

Pub Type(s)

Journal Article

Language

eng

PubMed ID

15982709

Citation

Charles, Amanda L., et al. "Toxicity of Uranium and Copper Individually, and in Combination, to a Tropical Freshwater Macrophyte (Lemna Aequinoctialis)." Chemosphere, vol. 62, no. 8, 2006, pp. 1224-33.
Charles AL, Markich SJ, Ralph P. Toxicity of uranium and copper individually, and in combination, to a tropical freshwater macrophyte (Lemna aequinoctialis). Chemosphere. 2006;62(8):1224-33.
Charles, A. L., Markich, S. J., & Ralph, P. (2006). Toxicity of uranium and copper individually, and in combination, to a tropical freshwater macrophyte (Lemna aequinoctialis). Chemosphere, 62(8), 1224-33.
Charles AL, Markich SJ, Ralph P. Toxicity of Uranium and Copper Individually, and in Combination, to a Tropical Freshwater Macrophyte (Lemna Aequinoctialis). Chemosphere. 2006;62(8):1224-33. PubMed PMID: 15982709.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Toxicity of uranium and copper individually, and in combination, to a tropical freshwater macrophyte (Lemna aequinoctialis). AU - Charles,Amanda L, AU - Markich,Scott J, AU - Ralph,Peter, Y1 - 2005/06/27/ PY - 2004/12/22/received PY - 2005/04/02/revised PY - 2005/04/29/accepted PY - 2005/6/29/pubmed PY - 2006/4/28/medline PY - 2005/6/29/entrez SP - 1224 EP - 33 JF - Chemosphere JO - Chemosphere VL - 62 IS - 8 N2 - 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 degrees 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 microg l-1, with a minimum detectable effect concentration (MDEC) of 3.2 microg l-1. The concentration of U inhibiting growth by 50% (EC50) was 758+/-35 microg l-1 with a MDEC of 112 microg l-1. The EC50 value for the exposure of L. aequinoctialis to equitoxic mixtures of Cu and U was significantly (P0.05) 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. SN - 0045-6535 UR - https://www.unboundmedicine.com/medline/citation/15982709/Toxicity_of_uranium_and_copper_individually_and_in_combination_to_a_tropical_freshwater_macrophyte__Lemna_aequinoctialis__ DB - PRIME DP - Unbound Medicine ER -