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 Spearman's 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 Spearman's 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-S-transferase rose (p<0.05) in all concentrations tested (0.108; 0.36 and 1.08 mg/l). Spearman's 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.

Assessment of contamination of the Svitava and Svratka rivers in the Czech Republic using selected biochemical markers.

The aim of the present study is to assess aquatic ecosystem contamination using selected biochemical markers: cytochrome P450, ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), tripeptide glutathione, vitellogenin, and 11-ketotestosterone in chub (Leuciscus cephalus L.). Seven locations on the Svitava and Svratka rivers (in the Brno conurbation, Czech Republic) were assessed. The results were compared with the levels of the most important inductors of these biomarkers: organic pollutants hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), DDT and its metabolites, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons in bottom sediment, fish muscle, and semipermeable membrane devices (SPMDs) and metals in sediment. The highest levels of pollutants were observed at sites situated downstream from Brno, especially at Modrice and Rajhradice. Significant positive correlations (p < 0.05) were found between EROD activity and HCH concentration in SPMDs, and also between GST and EROD activity with HCB concentration in muscle, after adjusting for age.

Fish biochemical markers as a tool for pollution assessment on the Svitava and Svratka rivers, Czech Republic.

OBJECTIVES: The study was designed to assess the pollution of the Svitava and Svratka rivers in and around the industrial city of Brno (Czech Republic) by persistent organic pollutants using selected biochemical markers in chub. DESIGN: Levels of selected biochemical markers were measured in liver and plasma samples of chub. The concentrations of persistent organic pollutants (POPs) were determined in bottom sediment, semi-permeable membrane devices (SPMDs) and muscle samples, and consequently used for correlation with biochemical markers. RESULTS: Significant alterations (p < 0.05) in some biochemical markers were observed and associated with combined exposure to pollutants. The highest levels of pollutants were found at sites situated downstream from Brno. The most widespread changes were identified in the function of phase I detoxifying enzymes. Significant positive correlations were observed in cytochrome P450 content and DDT concentration in the semi-permeable membrane device (p = 0.019, rs = 0.886), and between ethoxyresorufin-O-deethylase activity and content of DDT (p = 0.041, rs = 0.352) and polychlorinated biphenyls (p = 0.034, rs = 0.365) in muscle tissues of indicator fish. CONCLUSION: The results presented in our study indicate the highest contamination of sites situated downstream from Brno, where the intensive industrial and agricultural activities as well as domestic waste and sewage most probably comprise the main impact sources of the enhanced level of pollutants and some biochemical markers in fish.

Effects of subchronic exposure to Successor 600 (pethoxamid 600 g L-1) on common carp Cyprinus carpio.

OBJECTIVES: We investigated the effects of the herbicide preparation Successor 600 on biochemical and haematological indices and the histolopathological parameters of common carp after 28 day exposure. Furthermore, the hepatosomatic index and induction of xenobiotic metabolizing enzymes and biomarkers were assessed. DESIGN: Juvenile fish were exposed to sublethal concentrations of Successor(R) 600 (0.06 mg L-1, 0.22 mg L-1 or 0.60 mg L-1) for 28 days. Haematological indices were assessed using unified methods of haematological examination in fish. Plasma biochemical indices were measured by biochemical analyzer, the vitellogenin concentration in male fish plasma was estimated by direct sandwich ELISA. In hepatopancreas, ethoxyresorufin-O-deethylase (EROD) activity was measured spectrofluorimetrically, concentration of total cytochrome P450 (CYP), glutathion (GSH) content and glutathion-S-transferase (GST) activity were determined spectrophotometrically. Histological changes in samples of hepatopancreas, skin, gills, spleen, head kidney and trunk kidney were examined by light microscopy. RESULTS: Haemoglobin, MCH and MCHC were significantly (p<0.05) reduced in fish treated with Successor(R) 600 of 0.22 and 0.60 mg L-1. LDH was enhanced (p<0.05), in the highest concentration of the preparation. Vitellogenin was detected in all male fish, with no difference between groups. HSI, GSH and GST were elevated (p<0.05), owing to the exposure, whereas CYP and EROD were not affected. Slight histopathological changes were demonstrated in skin, gills and hepatopancreas, with steroid tissue in head kidney samples of 0.60 mg L-1 treated fish. CONCLUSION: Successor 600 affected the haematological profile of the treated fish, while the effects on biochemical indices were less expressed. Male plasma vitellogenin concentrations were not indicative of estrogen disruptive effects after 28 days. The importance of GSH and GST for the metabolisation were demonstrated. In contrast, CYP and EROD were not influenced by any concentration tested. HSI was found to reflex pollution with Successor 600. Histopathological indices caused by the treatment were observed in various tissue samples of the treated fish.

Effects of subchronic metribuzin exposure on common carp (Cyprinus carpio).

OBJECTIVES: Effects of metribuzin on biochemical and haematological indices, induction of specific biomarkers and impacts on biometric parameters of Cyprinus carpio were investigated for subchronic conditions. METHODS: Juvenile fish were exposed to 0.175 mg.L-1 or 1.75 mg.L-1 metribuzin for 28 days. Haematological indices were assessed using unified methods of haematological examination in fish. Biochemical indices were determined by biochemical analyzer, hepatic vitellogenin content was estimated by direct sandwich ELISA. Cytochrome P450 concentration and ethoxyresorufin O-deethylase activity were measured in liver spectrophotometrically and spectrofluorimetrically, respectively. RESULTS: Increased haematocrit and RBC count were found in fish exposed to 1.75 mg.L-1 metribuzin compared to control fish (p<0.05). Other indices contents and biomarkers levels were not significantly changed by either concentration of metribuzin. CONCLUSION: Sublethal metribuzin pollution may have adverse impacts on haematological parameters in common carp.

Biochemical markers for the assessment of aquatic environment contamination.

The need for assessment of aquatic ecosystem contamination and of its impact on water dwelling organisms was developed in response to rising aquatic environmental pollution. In this field study, liver enzymes of phase I and phase II of xenobiotic transformation, namely cytochrome P450, ethoxyresorufin-O-deethylase, glutathione-S-transferase and tripeptide glutathione were used to assess the contamination of the aquatic environment at different rivers in the Czech Republic. The indicator species selected was the male chub (Leuciscus cephalus L.) and male brown trout (Salmo trutta fario). Chemical analyses included also the assessment of the most important inductors of previously mentioned biochemical markers. The major inductors of monitored biomarkers are industrial contaminants which belong to a large group of organic pollutants (PCB, PAH, PCDD/F, DDT, HCH, HCB and OCS), persistent in the environment. Four different groups of river basins were assessed: the River Tichá Orlice and its tributary the Kralický brook; important tributaries of the River Elbe (the rivers Orlice, Chrudimka, Cidlina, Jizera, Vltava, Ohre and Bílina); major rivers in the Czech Republic (the rivers Luznice, Otava, Sázava, Berounka, Vltava, Labe, Ohre, Svratka, Dyje, Morava and Odra) and the River Vltava. The use of the biochemical markers together with chemical analyses seems to be an effective way to monitor the quality of aquatic environment.

Biomarkers of Contaminant Exposure in Chub (Leuciscus cephalus L.) - Biomonitoring of Major Rivers in the Czech Republic.

Biochemical analysis of organisms to assess exposure to environmental contaminants is of great potential use. Biochemical markers, specifically liver enzymes of the first and the second phase of xenobiotic transformation - cytochrome P450 (CYP 450), ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase (GST) and tripeptide reduced glutathione (GSH) - were used to assess contamination of the aquatic environment at 12 locations near the mouths of major rivers in the Czech Republic. These rivers were the Luznice, Otava, Sázava, Berounka, Vltava, Labe, Ohre, Svratka, Dyje, Morava and Odra. The indicator species selected was the Chub (Leuciscus cephalus L.). The highest levels of CYP 450 and EROD catalytic activity were found in livers of fish from the Labe (Obríství) (0.32±0.10 nmol mg-1 protein and 1061.38±545.51 pmol min-1 mg-1 protein, respectively). The highest levels of GST catalytic activity and GSH content were found in fish from the Otava (35.39±13.35 nmol min-1 mg-1 protein and 4.29±2.10 nmol GSH mg-1 protein, respectively). They were compared with levels of specific inductors of these biochemical markers in muscle. The results confirmed contamination of some river locations (Labe Obríství, Svratka).

Comparison of Mercury Distribution Between Liver and Muscle - A Biomonitoring of Fish from Lightly and Heavily Contaminated Localities.

Tissue samples from 1,117 fish of 25 species were collected from 1991 through 1996 at 13 locations along the River Elbe. The principal indicator species were perch (Perca fluviatilis) (n=118), chub (Leuciscus cephalus L.) (n=113) and roach (Rutilus rutilus) (n=138). Mercury (Hg) concentrations in muscle and liver were determined by atomic absorption spectrometry. The liver/muscle index in three indicator species from heavily contaminated and lightly contaminated localities were significantly different. In fish from heavily contaminated localities, Hg was deposited preferentially in the liver (the depository for inorganic and organic forms of Hg), while in lightly contaminated areas, it was deposited preferentially in muscle.

Biochemical Markers for Assessing Aquatic Contamination.

Biochemical markers, specifically enzymes of the first phase of xenobiotic transformation - cytochrome P450 and ethoxyresorufin-O-deethylase (EROD) - were used to determine the quantities of persistent organic pollutants (POPs) in fish muscle (PCB, HCB, HCH, OCS, DDT). Eight rivers were monitored (Orlice, Chrudimka, Cidlina, Jizera, Vltava, Ohre and Bílina; and the River Blanice was used as a control). The indicator species selected was the chub (Leuciscus cephalus L.). There were no significant differences in cytochrome P450 content between the locations monitored. The highest concentration of cytochrome P450 in fish liver was in the Vltava (0.241 nmol mg-1 protein), and the lowest was in the Orlice (0.120 nmol mg-1 protein). Analysis of EROD activity showed a significant difference between the Blanice and the Vltava (P< 0.05), and also between the Orlice and the Vltava (P< 0.01), the Orlice and the Bílina (P< 0.01), and the Orlice and the Ohre (P< 0.05). The highest EROD activity in fish liver was in the Vltava (576.4 pmol min-1 mg-1 protein), and the lowest was in the Orlice (63.05 pmol min-1 mg-1 protein). In individual locations, results of chemical monitoring and values of biochemical markers were compared. A significant correlation (P< 0.05) was found between biochemical markers and OCS, and PCB. Among the tributaries studied those that contaminated the Elbe most were the Vltava and the Bílina. These tributaries should not be considered the main sources of industrial contamination of the River Elbe, because the most important contamination sources were along the river Elbe itself.