A survey on Pb accumulation effects on fish liver and gill tissues of Rutilus rutilus caspius

Lead (Pb) is considered as one of the most destructive environmental pollutants causing extremely undesirable impacts on tissues of living organisms. In this trial, physiological and morphological changes in fish liver and gill tissues after Pb exposure for different terms and at various concentrations were investigated. To do so, samples were placed in aquaria containing 0.1, 0.2 and 0.4mg l-1 of Pb at different exposure times (46, 96, 144, and 168hrs). Afterwards fish were removed from the experimental tanks and their gill and liver tissues were sampled in order to determine any histopathological effects. The resulting stained slides were checked using a binocular microscope with a magnification of 10x and 40x. Histopathological changes in liver included sinusoidal extension, vacuolization, hyperemia and hemorrhage, nuclei picnosiation, hepatocyte necrosis, hemocydrine accumulation of melano macrophage cells. Cell acidofication, lymphocyte invasion and focal necrosis were also observed. Gill tissues were damaged by hyperemia, filament and secondary lamellae, mucosal accumulation, telansicatzy, dysplasia pavement cells metaplasia into mucosal cells and gill mucosa, and distal hyperplasia of secondary lamellae. Damages were intensified by an increase in the concentration of the contamination since minor histopathology occurred at 0.1mg l-1 of Pb while levels of 0.1, 0.2 and 0.4mg l-1 of Pb showed major histopathological effects as exposure time increased.