The effects of subchronic exposure to terbuthylazine on early developmental stages of common carp.

The aim of this study was to assess the impact of terbuthylazine in surface waters on fish under experimental conditions. Subchronic toxic effects on embryos and larvae of common carp (Cyprinus carpio) were investigated during a 30-day toxicity test. The exposure to terbuthylazin showed no effect on mortality, but significant differences (P < 0.0001) were revealed on weight and growth parameters at concentrations of 520 and 820 µg/L. The inhibition of specific growth rate at concentrations of 520 and 820 µg/L was 14% compared to the control group. No significant negative effects on total body length and body weight were observed at lower concentrations (0.9 and 160 µg/L). The concentrations 520 and 820 µg/L were associated with a delay in development compared to other experimental groups and controls. On the basis of weight and growth rate evaluation and determination of developmental stages, the No Observed Effect Concentration (NOEC) of terbuthylazine was estimated at 160 µg/L and the Lowest Observed Effect Concentration (LOEC) was 520 µg/L. According to these results, the reported environmental concentration of terbuthylazine in Czech rivers does not impact growth, development, morphology, or histology of carp embryos and larvae.