A study of toxicity and genotoxicity of copper, zinc and their mixture to rainbow trout (Oncorhynchus mykiss)

Abstract

The aim of the study was to evaluate the toxicity and genotoxicity of heavy metals (HM) (Cu and Zn) and their mixture to rainbow trout (Oncorhynchus mykiss). No significant alterations in the erythrocyte count and haemoglobin concentration were found after exposure to Cu, Zn and their mixture at all three concentrations studied. The most significant decrease (P < 0.001) in leukocyte count was determined in the blood of fish exposed to 0.25 LC50 of HM and their mixture, 0.125 and 0.0625 LC50 of HM mixtures. A slight, but significant increase (P < 0.05) in hematocrit level was found in the blood of fish exposed to a 0.125 LC50 concentration of Cu and HM mixture. The frequency of micronucleated erythrocytes (MNE) increased after exposure to HM and their mixture at all three concentrations studied (0.25, 0.125 and 0.06 LC 50) (P < 0.0001), but there were no significant differences in MNE levels among the concentrations studied (P = 0.136). After a 96-hour recovery (in clean water) of the fish exposed to a HM mixture, the levels of MNE significantly decreased at the highest and lowest concentrations studied (P = 0.0001 and P = 0.004, respectively). Keywords: fish, toxicity, genotoxicity, copper, zinc, micronuclei, haemotological parameters