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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.

ABSTRACT:In the European Union, the use of the insecticide NeemAzal T/S (standardised variant 1% of the active ingredient azadirachtin) is authorised in organic agriculture. The objective of this study was to determine the toxic effects of NeemAzal T/S at concentrations of 3, 10, 30, and 60 mg/l on the morphometric and condition characteristics, mortality, hatching, and histopathology of early-life stages of common carp (Cyprinus carpio L.) as a non-target aquatic organism, as well as related effects of NeemAzal T/S on selected indices of oxidative stress in the same organism. The embryo-larval toxicity test was performed according to OECD Guidelines 210 (Fish, Early-life Stage Toxicity Test). NeemAzal T/S exposure induced slow hatching on the first day and increased cumulative mortality in groups exposed to the insecticide. No effect on morphometric or condition characteristics was observed after 31 days of exposure. Histopathological changes of the gills were found at the highest concentration of 60 mg/l of NeemAzal T/S. Exposure at 30 mg/l was associated with significantly (P < 0.01) increased glutathione peroxidase and glutathione S-transferase (P < 0.05) activities compared to the control group. The content of oxidised lipids was significantly higher (P < 0.05) in the 3, 10, and 30 mg/l experimental groups than in the controls. NeemAzal T/S exerted a significant negative influence on histopathological parameters in the embryo and larvae of common carp, as well as on the indices of oxidative stress in the same organism.Keywords: Neemazal T/S; embryo-larval toxicity test; azadirachtin; oxidative stress; histopathology; insecticide List of abbreviations ANC 4.5 = acid neutralising capacity, CAT = catalase, COD Mn = chemical oxygen demand, FCF = fulton's condition factor, GPx = glutathione peroxidase, GR = glutathione reductase, GST = glutathione S-transferase, HE = haematoxylin and eosin, I = inhibition of specific growth, LC 50 = median lethal concentration, OECD = Organization for Economic Cooperation and Development, SGR = specific growth rate, TBARS = thiobarbituric acid reactive substances, TL = total length, W = weight Supported by the Czech Science Foundation (Grant No. P502/12/P163).

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.