Séverine Paris-Palacios

Biochemical and (ultra)structural hepatic perturbations of Brachydanio rerio (Teleostei, Cyprinidae) exposed to two sublethal concentrations of copper sulfate.

The aim of this study was to compare biochemical and (ultra)structural perturbations induced by Cu in the liver of Brachydanio rerio exposed for 14 days to sublethal concentrations of copper and then replaced for 14 days to clean water. Toxicity of Cu was clearly demonstrated: simultaneously to Cu accumulation, the liver developed large lysed areas and hepatocytic alterations. However, the majority of the parenchyma was composed of functional dark hepatocytes displaying typical feature of increased metabolism: development of rough reticulum, increase in size of nucleus and nucleolus, glycogenic depletion. Increase in hepatic protein content and of anti-oxidative defences (glutathione content, catalase and glutathione-S-transferase (GST) activities) indicated that the overall response of the liver was adaptative. In all hepatocytes a cord-like structure of the nucleoli was suspected to be associated to metal deposition. After 14 days depuration, the liver still contained high Cu concentrations and the hepatic alterations were not reversed. Such complementary studies are necessary for a better understanding of the deleterious effects of pollutants and for the development of biomarkers for metal toxicity.

Toxic effects and bioaccumulation of the herbicide isoproturon in Tubifex tubifex (Oligocheate, Tubificidae): a study of significance of autotomy and its utility as a biomarker.

Tubifex is the only animal reported to respond with autotomy to contamination. This response of contaminated worm is understood as a mode of metal excretion. Few data concern the potential of organic compounds to induce tubifex autotomy. The objective of this study was to investigate if autotomy can be induced by a herbicide isoproturon (IP) and be related to the way of excretion. Isoproturon accumulation in worm tissues and its effect on tubifex mortality, autotomy and regeneration rates were analysed after 4 and 7 days of exposure to the herbicide and also when worms were replaced for 10 days in clean water. IP accumulated in the same way in all parts of the worm body but IP metabolite rates were significantly higher in the posterior part of the worm. Thus the loss of the posterior part allows the worm to eliminate an important amount of pesticide. Autotomy has a population importance and is related to the degree of worm contamination so it may become an interesting biomarker.

Bages-Sigean and Canet-St Nazaire lagoons (France): physico-chemical characteristics and contaminant concentrations (Cu, Cd, PCBs and PBDEs) as environmental quality of water and sediment

Environmental characteristics in water and sediments of two contrasted coastal Mediterranean lagoons, Bages-Sigean and Canet-St Nazaire, were measured over a three season survey. The urban pollution (treatment plant discharges) is very important in Canet-St Nazaire lagoon reflecting untreated sewages, while in Bages-Sigean, the northern part appears more impacted due to larger anthropogenic inputs. Dissolved Cd concentrations are on the whole similar in both lagoons, whereas Cu concentrations are by far higher in lagoon Canet-St Nazaire. Cu concentrations appear to be highly dependent on dissolved organic carbon whereas salinity seems to control Cd variations. Concerning the sediments, the confined northern part of lagoon Bages-Sigean shows organic carbon and total nitrogen enrichment whereas lipid concentrations are much higher in the Canet-St Nazaire lagoon. Cu complexation seems to be strongly related to organic matter as evidenced by the two significant positive relationships, on one hand between Cu and organic carbon, and on the other hand, between Cu and lipids. On the contrary, Cd concentrations appear to be mainly controlled by carbonates. PCBs and PBDEs were detected only in sediments and show relatively low concentrations compared to similar lagoon environments. Regarding the sediment quality guidelines, Cd, Cu and PCBs in both lagoons did not exceed any Probable Effect Concentration (PEC).

Heavy metal contamination and hepatic toxicological responses in brown trout (Salmo trutta) from the Kerguelen Islands

The Kerguelen Islands include various species of freshwater fish such as brown trout (Salmo trutta). These trout are among the most isolated from direct anthropogenic impact worldwide. This study was designed to analyse cadmium (Cd) and copper (Cu) concentrations in the liver of Kerguelen brown trout, and to assess the possible impacts of these metals on hepatic histopathology and oxidative stress parameters (superoxide dismutase and catalase activity and glutathione levels). Trout were caught in the Château River, the Studer Lakes and the Ferme Pond, close to the scientific station of the Kerguelen Islands, corresponding to three morphotypes (river, lake and station). Kerguelen trouts’ hepatic concentrations of Cd and Cur were similar to those reported in previous studies in salmonids populations from areas under anthropological impacts. Clear hepatic disturbances (fibrosis, nuclear alteration, increased immune response, melanomacrophage centres [MMCs]) were observed in all tested trout. A similar histo-pathological trend was observed among the trout from the three morphotypes but anti-oxidative responses were higher in the trout from the “station” morphotype. Hepatic alterations and the presence of MMCs in the livers of Kerguelen brown trout may be related to the high levels of Cd and Cu measured in this fish at all sampling sites.

Metallothioneins in liver of Rutilus rutilus exposed to Cu2+. Analysis by metal summation, SH determination and spectrofluorimetry

Metallothioneins (MTs) have important roles in the homeostasis of essential metals and in the detoxication of heavy metals. They also represent a potential indicator of aquatic contamination by metals. Routine methods are needed for MTs quantification in ecotoxicological studies. This paper investigates the possibility to use the spectrofluorescent properties of Cu-MTs for MTs quantification. Cu displacement of metals coordinated to MTs and spectrofluorimetric determination of the obtained Cu-MTs was tested with commercial MTs and Cu2+-induced MTs in roach liver (Rutilus rutilus). Results of this original and simple spectrofluorimetric quantification of MTs presented a good correlation with data obtained with SH quantification, but not with metal summation evaluation of MTs (analysis of Zn, Cu and Cd coordinated to MTs). The three methods showed an clear induction of MTs in roach liver after 7 days of Cu2+ exposure. After 14 days of contamination, a reduction of hepatic MTs content was observable and not correlated to liver recovery. Results show that this low cost spectrofluorimetric method is useful to quantify MTs.