Effects of Polychlorinated Biphenyls on Liver Ultrastructure, Hepatic Monooxygenases, and Reproductive Success in the Barbel

in Ecotoxicology & Environmental Safety (1999), 42(3), 265-73

Polychlorinated biphenyls (PCBs) are organochlorinated micropollutants ubiquitously distributed in the environment. They are known to be strong inducers of hepatic monooxygenases in fish. This can ... [more ▼]

Polychlorinated biphenyls (PCBs) are organochlorinated micropollutants ubiquitously distributed in the environment. They are known to be strong inducers of hepatic monooxygenases in fish. This can adversely affect reproduction by increasing steroid metabolism. In this work, adult barbels were contaminated with food containing Aroclor 1260, a commercial PCB mixture from Monsanto, at environmentally relevant concentrations. A significant increase in cytochrome P450 was observed, and two particularly sensitive enzymes, ethoxyresorufin o-deethylase (EROD) and ethoxycoumarin o-deethylase (ECOD), were strongly induced. Electron microscopy revealed alterations in liver ultrastructure in contaminated fish, principally an increase in the number of cisternae of the rough endoplasmic reticulum, drastic glycogen depletion, dissolution of mitochondrial contents, and appearance of myelin figures. Contamination was also studied in relation to reproductive success in a hatchery. Contaminated males displayed no alteration in milt quality, but PCBs did alter female reproductive parameters. Total mortality of eggs and larvae increased significantly with the level of PCBs in the eggs. The most highly contaminated fish did not even spawn. All the adverse effects recorded here tended to be reversible when the intoxication ended, sometimes after only a 1-year detoxication period. [less ▲]

Some technical problems of feeding rate measurements in rotifers with fluorescently labelled algae.

Poster (1998, June 22)

Grazing of metazooplankton on phytoplankton and protozooplankton has been widely studied using the radiotracer technique. An interesting alternative to radioactive label is the use of fluorescent dies ... [more ▼]

Grazing of metazooplankton on phytoplankton and protozooplankton has been widely studied using the radiotracer technique. An interesting alternative to radioactive label is the use of fluorescent dies. Indeed, the use of fluorescently labelled algae (FLA) or protozoans does not imply particular security measures or equipment; moreover they allow the visualisation of the labelled prey in the predator sometimes providing useful informations on the variability between individuals and on the mechanism of feeding processes. Prior to the use of this method in ingestion rate measurements with Brachionus calyciflorus discrimination experiments were performed. The FLAs were Chlorella-like algae (Dictyosphaerium ehrenbergianum) labelled with DTAF (5-(4,6-dichlorotriazin-2-yl) aminofluorescein). The ingestion rate of the rotifer on the FLAs was 3 to 15 times lower than the ingestion rate on non labelled. Evidence was gathered that the staining procedure (heat-killing of the algae) was mainly responsible for the discrimination of the rotifer rather than the dye itself. Other technical considerations will be discussed like the occurrence of crashed algae in the rotifers gut and the inter-individual variability. [less ▲]

Quantification of the trophic pathway in the PCB contamination of two zooplanktonic species: Daphnia magna Straus and Brachionus calyciflorus Pallas

in Verhandlungen der Internationalen Vereinigung für Theoretische und Angewandte Limnologie = Proceedings of the International Association of Theoretical and Applied Limnology (1998), 26

Ultrastructural Modifications in Cultured Fetal Quail Hepatocytes Exposed to Pesticides and Pcbs

in Ecotoxicology & Environmental Safety (1996), 34(2), 145-55

There is increasing interest in cultured hepatocytes as a tool for solving toxicological and pharmacological problems while reducing laboratory animal experimentation. In the present study, fetal ... [more ▼]

There is increasing interest in cultured hepatocytes as a tool for solving toxicological and pharmacological problems while reducing laboratory animal experimentation. In the present study, fetal hepatocytes from the Japanese quail (Coturnix coturnix japonica) were used as an in vitro alternative model for evaluating the effects of PCBs and various pesticide-type chemicals on cell ultrastructure. Major alterations were demonstrated. The most striking effects of toxicants were an increase in the number of cisternae of the rough endoplasmic reticulum (RER), various alterations of mitochondrial morphology, a decreased glycogen content, vacuolization of the cytoplasm, and the appearance of concentric membrane arrays (CMA's), also called myelin-like figures. Other changes were sometimes observed, such as altered cell junctions, an increased lipid content, deformations of the nuclei, or the appearance of crystalline structures. These ultrastructural modifications seem to be dose-dependent. The present in vitro findings are validated by similar observations previously made in vivo on Japanese quail. They confirm the effectiveness of this technique as a biomonitoring tool for the evaluation of environmental quality. Yet the multiplicity of possible toxic effects, even for xenobiotics of a same category, makes it necessary to screen additional indicators of toxicity, such as the detoxifying activity of monooxygenases. [less ▲]

Relative importance of the trophic and direct pathways on PCB contamination in the rotifer species Brachionus calyciflorus (Pallas)

in Hydrobiologia (1995)

To determine the contribution of food ingestion (trophic pathway) to PCB contamination of zooplankton in the river Meuse (Belgium), we used 14 C-labelled algae (Dictyosphaerium ehrenbergianum) to measure ... [more ▼]

To determine the contribution of food ingestion (trophic pathway) to PCB contamination of zooplankton in the river Meuse (Belgium), we used 14 C-labelled algae (Dictyosphaerium ehrenbergianum) to measure ingestion and assimilation rates in the rotifer species Brachionus calyciflorus . When the concentration of algae in the culture medium varied from 20 103 to 200 103 algal cells ml -1 (0.12 to 1 .18 mg C 1 - '), the Brachionus calyciflorus ingestion rate varied from 0 .25 ± 0 .12 to 1 .52 ± 0 .43 ng C ind -1 h-1 at 15 °C and from 0 .74 ± 0 .17 to 5 .93 ± 0.61 ng Cind-' h-1 at 20 °C . The assimilation efficiency (ratio of the assimilation rate to the ingestion rate) measured in a culture medium containing 200 103 algal cells ml`' was 55 .7 ± 5.8%. Since the PCB concentration measured in the phytoplankton of the river Meuse is about 3 pg PCBs g -1 D.W., the estimated PCB contamination of zooplankton ascribable to the trophic pathway ranges from 0 .22 ± 0 .17 to 1 .31 ± 0.77 jag PCBs g -1 D.W. at 15 °C and from 0.64 ± 0 .34 to 5 .10 ± 2 .10 pg PCBs g -1 D. W. at 20'C . The lower figure based on measurements effected at 20 ° C is comparable to the actual level measured in zooplankton samples collected in the river Meuse (0 .69 ± 0.20 pg PCBs g`' D.W.) . The applicability of the formula used in our estimate was checked in a 48-hour in vitro experiment in which the rotifers were fed contaminated algae . The PCB accumulation measured in the rotifers was found to coincide with the calculated PCB contamination . Additional experiments were carried out to determine the contribution of the direct pathway to PCB contamination of zooplankton living in the river Meuse (0.02 pg PCBs 1-1 of water; average dissolved organic matter : 3 mg C 1 -1 ). The PCB concentration in zooplankton resulting from direct uptake of PCBs from the water was estimated at 0 .19 ± 0.05 jug PCBs g -1 D.W. These results show that in zooplankton living in polluted ecosystems, PCBs are likely to accumulate via the trophic pathway to concentrations up to 30 times higher than by direct contamination . Furthermore, our estimates of PCB contamination via the trophic pathway coincide quite well with actual concentrations measured in situ . [less ▲]

Etude des chlorations à la centrale Tihange

Report (1986)

Afin d'élimine(r les salissures qui se développent sur les parois des dispositifs de refroidissement, des chlorations sont pratiquées régulièrement dans les centrales électriques. La présente étude ... [more ▼]

Afin d'élimine(r les salissures qui se développent sur les parois des dispositifs de refroidissement, des chlorations sont pratiquées régulièrement dans les centrales électriques. La présente étude concernait la problématique des chlorations à la centrale de Tihange 1 et avait pour objectifs : i) de comprendre les différents processus physico-chimiques qui se passent à l'intérieur des circuits de la centrale et dans la Meuse; ii) de déterminer de quelle manière les processus de chloration ont un impact sur la qualité des eaux de la Meuse et sur le fonctionnement de son écosystème [less ▲]