Bioaccumulation and related effects of PCBs and organochlorinated pesticides in freshwater fish Hypostomus commersoni

Abstract

Few studies have investigated the bioaccumulation of persistent organic pollutants (POPs) in Brazilian native freshwater fish. In order to evaluate the bioavailability, potential risk to human exposure and the effects of POPs in the fish Hypostomus commersoni, muscle and liver samples of thirteen specimens were collected in a lake located in the city of Ponta Grossa (Parana State, Southern Brazil). Also, the liver and gills were considered for histopathological studies, and oxidative stress was investigated in the liver. Expressive concentrations of POPs were observed in the liver and muscle, with a total of 427 ± 78.7 and 69.2 ± 18.1 ng g⁻¹ dry weights of polychlorinated biphenyls (PCBs), respectively. Negative correlations between the concentration of several POPs and glutathione S-transferase and glucose-6-phosphate dehydrogenase were found. Otherwise, the cholinesterase activity in the muscle and brain presented positive correlations with the concentration of POPs. The hepatic bioaccumulation of some banned pesticides like aldrin, dieldrin and DDT was associated with various histopathological findings in the liver and gills. Necrotic areas, fibrosis, leukocyte infiltration, and the absence of macrophage centers were observed in the liver, indicating both chronic exposure and immunological suppression. Neoplasic changes were observed in the gills, confirming the carcinogenic potential reported for some of the investigated pollutants. The current work was the first to study the bioaccumulation of POPs in H. commersoni, an important species in ecological aspects and as a vehicle to human exposure to PCBs and organochlorine pesticides (OCPs).