Aquatic Sciences Meeting, Albuquerque 2001

CS37 Zooplankton

Date: Tuesday, February 13, 2001, Time: 4:30:00 PM

Location: Aztec

De la Hoz , E, A, Utah State University, Logan, USA, ead73@hotmail.com

Wurtsbaugh, W, A, Utah State University, Logan, USA, wurts@cc.usu.edu

HIGH TOXICITY OF BROMIDE TO COPEPODS AND DAPHNIA

Sodium bromide is used extensively in hydrological studies to trace water mass movements, with the assumption that is not toxic to aquatic organisms. However, results from short-term, static experiments with calanoid and cyclopoid copepods and Daphnia show that the acute toxicity varied from 0.6 mg Br/L to 4800 mg Br/L (LC50 values), depending on the species and the source of water used on the bioassays. Calanoid copepods were particularly susceptible with a LC50s varying from 0.6 for a soft-water species to 125 mg Br/L for a hard-water species. In contrast, Daphnia and cyclopoid copepods had LC50 values of 4000 and 4800 mg Br/L, respectively. The LC50 of Daphnia pulex (4000 mg Br/L) was lower than the reported for Daphnia magna (11 g Br/L). The high sensitivity of some crustaceans indicates that bromide may seriously impact aquatic communities if used at concentrations currently recommended for tracer experiments in field studies. The susceptibility of organisms to NaBr in a particular ecosystem should be tested prior to using it in field experiments.

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Aquatic Sciences Meeting, Albuquerque 2001

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