Influence of waterborne cations on zinc uptake and toxicity in rainbow trout, Oncorhynchus mykiss

Derek H. Alsop, Chris M. Wood

Research output: Contribution to journalArticle

52 Scopus citations

Abstract

The effects of waterborne cations on 65Zn uptake, Zn toxicity, and relationships with Ca uptake were examined in juvenile rainbow trout, Oncorhynchus mykiss, in soft water. Whole-body Zn uptake (waterborne [Zn] = 100 μg·L-1 = 1.5 μM) was greatly reduced by a variety of cations. This reduction was directly related to the concentration of positive charges, regardless of which ion carried that charge. Thus, 1.0 mM Na+, K+, NH4/+, and N-methyl-D-glucamine+ and 0.5 mM Mg2+ (divalent) reduced Zn uptake to a similar extent (~50%), indicating a relatively nonspecific competition for anionic sites on the gill. Ca2+ was an exception and was more potent at reducing Zn uptake, likely because only Ca2+ would also compete for absorption. Although Na+ and Mg2+ were able to markedly reduce Zn uptake, they had no effect on Zn toxicity (measured with 96-h LC50 tests), a result paralleled by their inability to restore Ca2+ uptake that was inhibited by Zn. In contrast, Ca2+ reduced Zn toxicity and restored Ca2+ uptake. These results partially dissociate Zn uptake from Zn toxicity, implicate disturbed Ca2+ uptake as the toxic mechanism, and have profound implications for water quality criteria where Ca2+ and Mg2+ (the two 'hardness' cations) are traditionally considered to be equally protective.

Original languageEnglish (US)
Pages (from-to)2112-2119
Number of pages8
JournalCanadian Journal of Fisheries and Aquatic Sciences
Volume56
Issue number11
DOIs
StatePublished - Jan 1 1999

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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