The chronic effects of terbuthylazine-2-hydroxy on early life stages of marbled crayfish (Procambarus fallax f. virginalis).

This study assessed the chronic effects of terbuthylazine-2-hydroxy (T2H), one of the main terbuthylazine degradation products, on early life stages of marbled crayfish (Procambarus fallax f. virginalis) by means of mortality, growth rate, early ontogeny, oxidative stress, antioxidant defence and histopathology. The crayfish were exposed to four concentrations of the tested substance as follows: 0.75µg/l (environmental concentration), 75, 375 and 750µg/l for 62days. Concentrations over 75µg/l caused lower weight compared to the control group. T2H at 750µg/l caused delay in ontogenetic development. Levels of thiobarbituric acid reactive substances and total superoxide dismutase activity were significantly (p<0.01) lower in groups exposed to 375 and 750µg/l T2H. Crayfish in these treatments also showed alteration of tubular system including disintegration of tubular epithelium with complete loss of structure in some places of hepatopancreas and wall thinning up to disintegration of branchial filaments with focal infiltrations of hemocytes. In conclusion, chronic terbuthylazine-2-hydroxy exposure in concentrations up 75µg/l (100 times higher than environmental concentration) affected growth, ontogenetic development, antioxidant system, caused oxidative stress and pathological changes in hepatopancreas of early life stages of marbled crayfish.

Effects of prometryne on early life stages of common carp (Cyprinus carpio L.).

Toxicity of prometryne to early life stages of common carp was assessed. On the basis of accumulated mortality in the experimental groups lowest observed-effect concentration (LOEC) was estimated as 1100 µg/l; and no observed-effect concentration (NOEC) was 850 µg/l. Fulton's condition factor was significantly lower than in controls in fish exposed to 4000 µg/l after 7, 14, and 21 days. By day 14, fish exposed to 4000 µg/l prometryne showed significantly lower mass and total length compared to controls. Fish exposed the 1200 and 4000 µg/l showed delay in development, severe hyperaemia in gill, liver, and caudal and cranial kidney. Subchronic prometryne exposure of early-life stages of common carp at concentrations of 1200 and 4000 µg/l affected their survival, growth rate, early ontogeny, and histology.

Effects of terbuthylazine on early life stages of common carp.

OBJECTIVES: The aim of this study was to assess the toxicity of terbuthylazine in different developmental stages of common carp (Cyprinus carpio) on the basis of mortality, early ontogeny, occurrence of morphological anomalies, growth rate, and Fulton's condition factor during and at the conclusion of the test. DESIGN: The toxicity tests were performed on carp according to OECD 210 methodology. The developmental stages of carp were exposed to terbuthylazine at four concentrations, 2.9 (reported environmental concentration in Czech rivers); 70; 1,400; and 3,500 µg.L(-1) for 35 days and compared to carps in a non-treated control group. RESULTS: Terbuthylazine in concentration 1,400 and 3,000 µg.L(-1) caused significant (p<0.01) decrease of mass, total length and delayed in development of carp. Fish exposed to terbuthylazine showed alteration of tubular system of caudal kidney. On the basis of histopathological changes the values of LOEC=2.9 µg.L(-1) terbuthylazine were estimated. CONCLUSIONS: Chronic terbuthylazine exposure of early-life stages of common carp affected their growth rate, early ontogeny and histology. Some of the changes were observed only at higher exposures, but change founded in caudal kidney was affected in fish exposed to the real environmental concentration tested (i.e., 2.9 µg.L(-1)).

The effect of subchronic metribuzin exposure to signal crayfish (Pacifastacus leniusculus Dana 1852).

OBJECTIVES: The aim of the study was to investigate effects of the triazine herbicide metribuzin on signal crayfish Pacifastacus leniusculus Dana by determining oxidative stress (thiobarbituric acid reactive substances) and antioxidant indices (total superoxide dismutase, catalase, glutathione reductase) in hepatopancreas, muscle, and gill as well as assessing their histopathology. DESIGN: Crayfish were exposed to metribuzin concentrations of 0.52 µg x l(-1) (realistic environmental concentration) and 3.06 mg x l(-1) (10% 96hLC50) for 10 and 30 days followed by a 30-day depuration period without exposure to metribuzin. RESULTS: In the thiobarbituric acid reactive substances, superoxide dismutase, and catalase were observed differences in all examined tissues compared to the control group. Differences from control were observed in glutathione reductase activity in hepatopancreas after 10 days for both exposure concentrations and after 30 days at 3.06 mg x l(-1). Histological examination revealed extensive focal autolytic disintegration of tubular epithelium in hepatopancreas of crayfish exposed to metribuzin for 30 days. CONCLUSIONS: Chronic exposure of metribuzin resulted in oxidative damage to cell lipids, in changes of antioxidant activity in crayfish tissue, and pathological changes in hepatopancreas. The results suggest that selected oxidative stress biomarkers, antioxidant enzymes, and pathologies of hepatopancreas may have potential as biomarkers for monitoring residual triazine herbicides in the aquatic environment.

Effect of prometryne on early life stages of marbled crayfish (Procambarus fallax f. virginalis).

OBJECTIVES: The aim of this study is to assess the toxicity of prometryne in early life stages of marbled crayfish (Procambarus fallax f. virginalis) on the basis of mortality, early ontogeny, growth rate, and histopathology during and at the end of the test. DESIGN: The early life stages of marbled crayfish were exposed to prometryne at four concentrations, 0.51, (reported concentration in Czech rivers), 144, 1440, and 4320 µg x l(-1) for 53 days and compared to crayfish in a non-treated control group. RESU LTS: Prometryne in concentration 144, 1444 and 4320 µg x l(-1) caused decrease of weight and specific growth rates of crayfish. Crayfish exposed the highest concentration 4320 µg x l(-1) showed delay in ontogeny development. All crayfish groups exposed to prometryne showed histopathological changes in gill. On the basis of histopathological changes the values of LOEC = 0.51 µg x l(-1) and NOEC = for 0.10 µg x l(-1) of prometryne for marbled crayfish juveniles was estimated. CONCLUSIONS: Chronic exposure of prometryne on early life stages of crayfish has affected their mortality, growth rate, and histology. Some of the changes were observed only at higher exposures (144, 1444 and 4320 µg x l(-1)), but histopathological changes in gills were observed also in crayfish exposed to the real environmental concentration in Czech rivers (i.e. 0.51 µg x l(-1)), which is about 9 times lower than maximal concentration (4.40 µg x l(-1)) reported in surface waters of Greece. Concentrations of prometryne in World rivers have been reported to generally vary in the range of 0.1-4.40 µg x l(-1).

Effects of the terbuthylazine metabolite terbuthylazine-desethyl on common carp embryos and larvae.

Toxicity of terbuthylazine-desethyl to embryos and larvae of common carp (Cyprinus carpio) was assessed. Based on mortality, the lethal concentration of terbuthylazine-desethyl was estimated to be 31days LC50=441.6µg/L. Carp exposed to terbuthylazine-desethyl at 1800µg/L exhibited lower weight and length at 7days of exposure compared to the control group. By day 20, carp exposed to 900µg/L terbuthylazine-desethyl showed lower weight and length compared to control group. Terbuthylazine-desethyl in concentrations (180, 900, and 1800µg/L) caused delay in ontogenetic development. Total superoxide dismutase activity was significantly lower in all exposed groups. Exposure to 180 and 900µg/L terbuthylazine-desethyl was associated with alteration of the caudal kidney tubular system including peritubular dilatation detachment of epithelial cells from the basal lamina, and focal autolytic disintegration of the tubular epithelia. Chronic terbuthylazine-desethyl exposure affected survival, growth, ontogenetic development, and the antioxidant system and caused pathological changes to the caudal kidney.

Effect of terbuthylazine-2-hydroxy at environmental concentrations on early life stages of common carp (Cyprinus carpio L.).

The aim of the study was to investigate effects of the triazine's herbicide terbuthylazine-2-hydroxy on early life stage of common carp (Cyprinus carpio L.) through antioxidant indices, mortality, growth, development, and histopathology. Based on accumulated mortality in the experimental groups, lethal concentrations of terbuthylazine-2-hydroxy were estimated at 35-day LC50 = 10.9 mg/L terbuthylazine-2-hydroxy. By day 15, fish were exposed to 3.5 mg/L and by day 26, fish were exposed to 0.0029 mg/L; real environmental concentration in Czech rivers, 0.07 mg/L, 1.4 mg/L, and 3.5 mg/L terbuthylazine-2-hydroxy, showed significantly lower mass and total length compared with controls. Based on inhibition of growth in the experimental groups, lowest observed effect concentration (LOEC) = 0.002 mg/L terbuthylazine-2-hydroxy and no observed effect concentration (NOEC) = 0.0001 mg/L terbuthylazine-2-hydroxy. No significant negative effects on hatching or embryo viability were demonstrated at the concentrations tested, but significant differences in early ontogeny among groups were noted. Fish from the two highest tested concentrations showed a dose-related delay in development compared with the controls. Total superoxide dismutase (SOD) activity was significant lower in all groups testedly for terbuthylazine-2-hydroxy compared with the control group. At concentrations of 1.4 and 3.5 mg/L damage to caudal kidney tubules when compared to control fish was found.