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The aim of this study was to investigate the effects of subchronic exposure to atrazine on fish growth and the development of histopathological changes in selected organs (gill, kidney, liver) in Danio rerio. Juvenile growth tests were performed on D. rerio according to OECD method No. 215. For 28 days, fish at an initial age of 30 days were exposed to the environmental atrazine concentration commonly detected in Czech rivers (0.3 μg/L) and a range of sublethal concentrations of atrazine (3.0, 30.0 and 90.0 μg/L). The results showed decreasing growth rates and morphological changes in the liver (dystrophic lesions of hepatocytes) at 90.0 μg/L of atrazine. The environmental concentration of atrazine in Czech rivers did not have any effect on fish growth and development of histopathological changes in D. rerio. The value of NOEC was 30.0 μg/L and the value of LOEC was 90.0 μg/L.

The aim of this study was to investigate effects of subchronic exposure to sublethal levels of diclofenac on growth, oxidative stress, and histopathological changes in Danio rerio. The juvenile growth tests were performed on Danio rerio according to OECD method number 215. Fish at the age of 20 days were exposed to the diclofenac environmental concentration commonly detected in the Czech rivers (0.02 mg L−1) and the range of sublethal concentrations of diclofenac (5, 15, 30, and 60 mg L−1) for 28 days. A significant decrease (P < 0.01) in the fish growth caused by diclofenac was observed in the concentrations of 30 and 60 mg L−1. The identified value of LOEC (lowest observed effect concentration) was 15 mg L−1 of diclofenac and NOEC (no observed effect concentration) value was 5 mg L−1 of diclofenac. We did not find histopathological changes and changes of selected parameters of oxidative stress (glutathione S-transferase, glutathione reductase) in tested fish. The environmental concentration of diclofenac in Czech rivers did not have any effect on growth, selected oxidative stress parameters (glutathione S-transferase, glutathione reductase), or histopathological changes in Danio rerio but it could have an influence on lipid peroxidation.

The authors performed a toxicity test with ciprofloxacin in fertilized eggs of common carp according to guideline 210 of the Organisation for Economic Co-operation and Development. The tested concentrations were 1 μg L(-1) , 100 μg L(-1) , 500 μg L(-1) , 1000 μg L(-1) , and 3000 μg L(-1) . Accelerated hatching was found in all groups exposed to ciprofloxacin, but significant growth reduction was found only in the group exposed to the highest concentration (3000 μg L(-1) ). Increased numbers of macroscopic morphological anomalies were observed on day 6 of the test (after hatching). The highest numbers of macroscopic morphological anomalies were observed in the groups of free embryos and larvae exposed to ciprofloxacin concentrations of 100 μg L(-1) , 500 μg L(-1) , 1000 μg L(-1) , and 3000 μg L(-1) (20-23% of tested samples). A gradual decrease in glutathione S-transferase activity was detected in all experimental groups exposed to ciprofloxacin, but significant differences (p < 0.01) were found only in groups treated with 500 μg L(-1) and 3000 μg L(-1) . Glutathione peroxidase and catalase exhibited increased activity in most of the tested concentrations (p < 0.01 and <0.05, respectively), whereas decreased glutathione reductase activity was found in the groups exposed to ciprofloxacin concentrations of 500 μg L(-1) and 3000 μg L(-1) (p < 0.05). The concentration of thiobarbituric acid-reactive substances was significantly lower (p < 0.01) in all experimental groups exposed to ciprofloxacin. The lowest-observed-effect concentration of ciprofloxacin was 1 μg L(-1) . These results suggest that hatching, early ontogeny, occurrence of morphological anomalies, antioxidant and biotransformation enzyme activity, and lipid peroxidation in fish can be affected by ciprofloxacin. Environ Toxicol Chem 2016;35:1733-1740. © 2015 SETAC.

Ketoprofen residues have been found in surface water where they present a potential risk to nontarget aquatic species. The aim of this study was to assess the impact of ketoprofen in surface waters on fish under experimental conditions. Subchronic toxic effects on 300 embryos and larvae of common carp (Cyprinus carpio) were investigated during a 30 day toxicity test with concentrations of ketoprofen: 0.003, 2.1, 6.3 and 21 mg/l. The exposure to ketoprofen showed no effect on mortality, but we observed significant delay (P < 0.05) in hatching in day 3 in fish exposed to all concentrations of ketoprofen. Significant delays (P < 0.05) in development were revealed at 2.1, 6.3 and 21 mg/l ketoprofen. On the basis of weight and growth rate evaluation and the determination of developmental stages, the lowest observed effect concentration was 0.003 mg/l. According to these results, the reported environmental concentration of ketoprofen in Czech rivers could have a negative effect on the growth and development of carp embryos and larvae. These tests have not yet been performed. Further research and search for a mechanism to reduce the incidence of ketoprofen in the waters by better wastewater treatment is required.

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The aim of this study was to assess the impact of metribuzin in surface waters on fish under experimental conditions. The effects of subchronic exposure to metribuzin on fish growth and the development of histopathological changes in selected organs (gill, kidney, liver) and on activity of some biochemical markers (CYP450, EROD) in Danio rerio were investigated during a 28-day toxicity test. Juvenile growth tests were performed on D. rerio according to OECD method number 215. Fish at an initial age of 30 days were exposed to a range of metribuzin concentrations (1.5, 5, 16, 33, and 53 mg L−1). Exposure to metribuzin at 53 mg L−1 was associated with increased mortality. Negative effects with regard to total body weight, length, and the inhibition of specific growth rate were induced at concentrations of 33 and 53 mg L−1. Histopathological examination revealed pathological lesions in the liver in pesticide-exposed fish only at the highest concentration of 53 mg L−1 of metribuzin. Based on the results of growth rate, biochemical markers (CYP450, EROD), and histopathological examination, the lowest observed effect concentration (LOEC) value was 33 mg L−1 and the no observed effect concentration (NOEC) value was 16 mg L−1.