Respiration and osmo regulation in rainbow trout salmo gairdneri exposed to hexavalent chromium at different ph values
Van Der Putte, I.; Laurier, M.B.H.M.; Van Eijk, G.J.M.
Aquatic Toxicology 2(2): 99-112
ISSN/ISBN: 0166-445X DOI: 10.1016/0166-445x(82)90009-1
Recordings were made of the ventilation frequency, coughing rate and O2 uptake rate of rainbow trout (S.gairdneri) subjected for 4 days to sublethal levels of Cr6+. Experiments were conducted at pH values of 7.8 and 6.5 and concentrations ranging between 5-50 and 1-10 mg/l Cr, respectively. During exposure no significant effect of Cr on O2 uptake rate was detected. The ventilation frequency and coughing rate increased proportionally to an increase in metal concentration, with fish being more susceptible at the lower pH. Alterations in blood and plasma variables determined after exposure included a significant dose-dependent decrease in plasma osmolality and some electrolyte concentrations and an increase in Hb, hematocrit, plasma glucose and lactate levels. The pattern of these changes was dependent on pH and exposure concentration and seemed to be related with Cr-induced histological alterations. At pH 7.8 and 6.5 an osmoregulatory and respiratory dysfunction were part of the physiological mechanism of Cr6+ toxicity.