ISSN:
1432-136X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary 1. Rainbow trout exposed to waterborne zinc at an acutely lethal level (1.5 mg/l) or at a lower concentration close to the 4 d LC50 (0.8 mg/l) exhibited contrasting physiological responses in artificial soft water (ASW). 2. The changes in acid-base status and other blood parameters during the acute zinc exposure (1.5 mg/l) in ASW resulted from a rapid cascade of events in which hypoxemia, probably due to gill damage, resulted in tissue hypoxia and a mixed acidosis which were rapidly fatal. Changes in Het, MCHC, Cl− and lactate reflected the acidosis. Hypoxia rather than acidosis was the primary lethal mechanism. 3. Lower level zinc exposure (0.8 mg/l) over a 3 day period resulted in a slight alkalosis, despite a rise in $$P{\text{a}}_{{\text{CO}}_{\text{2}} }$$ . No changes were observed in plasma concentrations of Na+, Cl− or K+, and $$P{\text{a}}_{{\text{O}}_{\text{2}} }$$ remained high. Possible causes for the alkalosis are discussed. Some mortality occurred, suggesting that toxic mechanisms other than hypoxemia may have operated. 4. Zinc accumulated in whole blood to a greater extent during the 3 day low level exposure than the short term, high level exposure, suggesting that toxicity in the latter reflected an external effect of zinc. Zinc accumulated only in plasma with no penetration of the RBC's.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00684139
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