Zuzana Siroka

Effects of pollution on chub in the River Elbe, Czech Republic

The Elbe River is one of the most polluted aquatic ecosystems in the Czech Republic. The effect of three major chemical plants located on the Elbe River (at Pardubice, Neratovice, and Usti nad Labem) on fish was studied in 2004. Health status, chemical concentrations (Hg, PCB, DDT, HCH, HCB, OCS, 4-tert-nonylphenols, 4-tert-octylphenol) in muscle, and biomarkers (hepatic ethoxyresorufin-O-deethylase (EROD), plasma vitellogenin, and plasma 11-ketotestosterone) were assessed in male chub (Leuciscus cephalus L.). Differences between localities upstream (US) and downstream (DS) from the monitored source of pollution were identified. Fish from DS sampling sites showed significantly higher levels of contaminants than fish from US sampling sites. Generally, the concentrations of pollutants in fish from the Elbe sites were significantly higher compared to the reference site. Reduced gonad size, decreased plasma levels of 11-ketotestosterone, EROD and vitellogenin induction, and histopathologies of male gonads indicated harmful effects of aquatic pollution in fish from the Czech portion of the Elbe River.

Biochemical markers of contamination in fish toxicity tests

Biochemical markers of contamination in fish toxicity tests Markers of xenobiotic metabolization (cytochrome P450, ethoxyresorufin-O-deethylase, glutathione and glutathione-S-transferase) were investigated in the liver of the common carp Cyprinus carpio after 28-day exposure to different pesticide formulations. The fish exposed to herbicide Sencor 70 WG (metribuzin 700 g/kg) of 0.25 and 2.5 mg/l showed no change in cytochrome P450 and activity of ethoxyresorufin-O-deethylase when compared to control. Successor 600 (pethoxamid 600 g/l) of 0.06; 0.22 and 0.60 mg/l did not affect either cytochrome P450 or the activity of ethoxyresorufin-O-deethylase. However, in fish exposed to Successor 600 of 0.22 and 0.60 mg/l, there was a rise in glutathione and in the activity of glutathione-S-transferase (p<0.05), with Spearmans correlation r = 0.23 at p<0.05. Spartakus (prochloraz 450 g/l) of 0.36 and 1.08 mg/l induced cytochrome P450 and ethoxyresorufin-O-deethylase (p<0.05), with Spearmans correlation r = 0.49 at p<0.01. Glutathione increased in fish exposed to 1.08 mg/l (p<0.05), the activity of glutathione-Stransferase rose (p<0.05) in all concentrations tested (0.108; 0.36 and 1.08 mg/l). Spearmans correlation between glutathione and GST was r = 0.38; p<0.01). The obtained data contribute to a better understanding of detoxification of the selected xenobitics in fish. Although biomarkers of the first phase of metabolization are considered to be more sensitive, our results indicate higher sensitivity of the second phase biomarkers.

Effect of salicylic acid on early life stages of common carp (Cyprinus carpio).

Environmental concentrations of pharmaceutical residues are often low; nevertheless, they are designed to have biological effects at low doses. The aim of this study was to assess the effects of salicylic acid on the growth and development of common carp (Cyprinus carpio) early life stages with respect to antioxidant defence enzymes. An embryo-larval toxicity test lasting 34 days was performed according to OECD guidelines 210 (Fish, Early-life Stage Toxicity Test). The tested concentrations were 0.004, 0.04, 0.4, 4 and 20mg/l of salicylic acid. Hatching, early ontogeny, and both morphometric and condition characteristics were significantly influenced by subchronic exposure to salicylic acid. Also, changes in antioxidant enzyme activity and an increase in lipid peroxidation were observed. The LOEC value was found to be 0.004 mg/l salicylic acid. The results of our study confirm the suggestion that subchronic exposure to salicylic acid at environmental concentrations can have significant effects on aquatic vertebrates.