Costs of chronic waterborne zinc exposure and the consequences of zinc acclimation on the gill/zinc interactions of rainbow trout in hard and soft water

Journal Article · Sat May 01 04:00:00 EDT 1999 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1002/etc.5620180529· OSTI ID:361945

Alsop, D H; McGeer, J C; McDonald, D G; Wood, C M ^[1]

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1. McMaster Univ., Hamilton, Ontario (Canada). Dept. of Biology

Juvenile rainbow trout were exposed to zinc in both moderately hard water and soft water for 30 d. Only the 450 {micro}g/L zinc-exposed fish experienced significant mortality. Zinc exposure caused no effect on growth rate, but growth affected tissue zinc levels. Whole body zinc levels were elevated, but gill sand liver showed no consistent increases relative to controls over the 30 d. Therefore, tissue zinc residues were not a good indicator of chronic zinc exposure. After the 30-d exposure, physiological function tests were performed. Zinc was 5.4 times more toxic in soft water. All zinc-exposed trout had acclimated to the metal, as seen by an increase in the LC50 of 2.2 to 3.9 times over that seen in control fish. Physiological costs related to acclimation appeared to be few. Zinc exposure had no effect on whole body Ca{sup 2+} or Na{sup +} levels, on resting or routine metabolic rates, or on fixed velocity sprint performance. However, critical swimming speed (U{sub Crit}) was significantly reduced in zinc-exposed fish, an effect that persisted in zinc-free water. Using radioisotopic techniques to distinguish new zinc incorporation, the gills were found to possess two zinc pools: a fast turnover pool and a slow turnover pool. The fast pool was much larger in soft water than in hard water, but at most it accounted for < 3.5% of the zinc content of the gills. The size of the slow pool was unknown, but its loading rate was faster in soft water. Chronic zinc exposure was found to increase the size of the fast pool and to increase the loading rate of the slow pool.

• Sponsoring Organization: USDOE
• OSTI ID: 361945
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 5 Vol. 18; ISSN 0730-7268; ISSN ETOCDK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL ADAPTATION
BIOLOGICAL INDICATORS
CHRONIC EXPOSURE
TISSUE DISTRIBUTION
TOXICITY
TROUT
WATER POLLUTION
ZINC