Biomonitoring of polychlorinated biphenyls (PCBs) in heavily polluted aquatic environment in different fish species.

The distribution and concentrations of polychlorinated biphenyls (PCBs) were determined in fish species (European perch Perca fluviatilis, northern pike Esox lucius, pike perch Sander lucioperca, wels catfish Silirus glanus, common carp Cyprinus carpio, European eel Anguilla anguilla, freshwater bream Abramis brama, goldfish Carassius auratus, and roach Rutilus rutilus) in a heavily polluted water reservoir Zemplínska sírava (Slovakia). The study performed at two different time points 5 years apart (2004 and 2009) revealed serious PCB contamination of fish muscle tissue and significant interspecies as well as tissue-specific differences in PCB uptake by fish. Total PCBs broadly correlated with the trophic position of individual fish species within a food chain (P < 0.01). The concentrations were particularly high in predatory fish species, perch, pike, and pike perch (108.0, 90.1, and 113.0 mg kg(-1) lipid wt, respectively), but comparable PCB values were also found in non-predatory detrivorous freshwater bream (128.0 mg kg(-1) lipid wt). The lowest PCB values were surprisingly assessed in European eel (17.1 mg kg(-1) lipid wt). Tissue analysis showed the highest storage capacity of the liver (hepatopancreas in cyprinids) with maximum concentrations recorded found in northern pike (214.0 mg kg(-1) lipid wt) and freshwater bream (163.0 mg kg(-1) lipid wt). Negative correlations, mostly not significant, between the total PCB concentrations and fish weight were observed (P > 0.05). The study has shown that the kind of fish, its feeding habit, and specific conditions of the habitat are mutually interrelated factors that are responsible for significant variations in fish body burdens. A tendency to PCB biomagnification was also proved in some fish species of this water reservoir.

Morphological and genetic characterization of Echinococcus granulosus in the Slovak Republic.

The present study was undertaken to characterize more thoroughly aetiological agent of cystic echinococcosis that still represents a health problem in the Slovak Republic. Sequencing of the mitochondrial ND1 gene, Random Amplified Polymorphic DNA (RAPD) analysis and isoenzyme analyses were used to characterize genetically protoscolices of 37 isolates from pigs and cattle and two isolates from humans collected in different regions of the Slovak Republic. Solely the G7 genotype (pig strain) was identified by ND1 sequences in all 14 pigs isolate examined by this method. This genotype was also found in two human patients and in two cattle. The exclusive finding of the G7 variant has implications for the implementation of control strategies given its unique developmental and biological properties. Despite striking morphological variability, a low degree of the intra-strain variability was found in the Slovak Echinococcus granulosus isolates with the genetic methods used. This was particularly associated with the shape and size of hooks, number of testes and shape of ovaries and uterus. GPI and MDH enzymes were found suitable for the discrimination of G7 and G1 (=cosmopolitan sheep strain) variant.