Alterations in selected haematological parameters of rainbow trout (Oncorhynchus mykiss) exposed to complex mixtures of contaminants

The aim of the study was to evaluate and compare changes in the selected haematological parameters of rainbow trout after long-term (14 days) exposure to sublethal concentrations of two kinds of contaminants: 1) highway traffic emission pollutants (model mixture of heavy metals) and 2) road maintenance salt. Four groups of fish exposed to sublethal concentrations of model mixture metal solutions demonstrated an increased frequency of abnormal erythrocytes and elevated percentage of neutrophiles. The percentage of juvenile and abnormal erythrocytes was significantly increased in the blood of fish exposed to sublethal concentrations of road maintenance salt solutions. Our data confirm that even low amounts of metals found in soil near roadsides and road maintenance salt can induce adverse effects on fish. Morphological analysis of erythrocytes seems to be a reliable tool for detection of toxic effects upon fish.