Oxygen uptake and gill morphological alterations in Procambarus clarkii (Girard) after sublethal exposure to lead

The effects of sublethal lead concentrations on the oxygen uptake in whole animals and excised gill of Procambarus clarkii, as well as the gill morphological alterations, were investigated. Oxygen uptake rates of whole crayfish showed a great variability and decreased as the lead concentration increased. Significant differences were not found (ANOVA, P greater than 0.05). Oxygen consumption of excised gills decreased significantly as the lead concentration increased (P less than 0.01). Macroscopic and microscopic observations of the gill filaments of crayfish treated with 200 mg Pb/l indicated a general disorganization. The filaments showed the apices rounded and they appeared grossly blackened.