Hazardous pollutants in the environment: Fish host-parasite interactions and bioaccumulation of polychlorinated biphenyls

The present paper reports on the interrelationships of fish, parasites and the bioaccumulation of hazardous organic compounds in the Zemplinska Sirava water reservoir in eastern Slovakia, which is heavily polluted with polychlorinated biphenyls (PCBs). The concentrations of these contaminants were measured in various fish matrices (dorsal and abdominal muscle tissues, hepatopancreas, intestine wall and adipose tissue) of the freshwater bream, Abramis brama (Cyprinidae), and in its intestinal parasite Caryophyllaeus laticeps (Cestoda), which was used for the first time as a model for a PCB bioaccumulation study. Regarding the fish, the highest concentrations of PCBs were found in the intestine, followed by hepatopancreas and muscle tissues. The amounts of PCBs were higher in abdominal muscles than in their dorsal parts. Concentrations of Sigma PCBs above the limits set by European regulations were detected in both muscle parts in the fish, confirming the persistent unfavorable conditions in this locality and high risk for biota and humans. Based on bioconcentration factor values (BCFs), PCBs reached much higher levels in cestodes compared to bream matrices. Some significant differences in PCB amounts between infected and uninfected bream were determined. Fulton's condition factor (CF) significantly differed in infected and non-infected fish (p < 0.05), with CF values surprisingly lower in fish free of parasites compared to parasitized fish, which suggests a mutualistic relationship between the parasite and its host.

Automated summary

This paper explores the interrelationships of fish, parasites, and hazardous organic compounds in the Zemplinska Sirava water reservoir in eastern Slovakia, where PCB contamination is heavy. It was found that PCB concentrations were highest in the intestine of freshwater bream, followed by the hepatopancreas and muscle tissues, with higher levels in abdominal muscles than dorsal parts. Additionally, the study revealed that PCB levels were much higher in cestodes compared to bream matrices, indicating a mutualistic relationship between the parasite and its host.