Fish biomarkers for environmental monitoring within the Water Framework Directive of the European Union

International audienceIn the past 25 years, numerous biomarkers have been developed with the objective to apply them for environmental biomonitoring. Recently, the Water Framework Directive (WFD) of the European Union specified monitoring programs required to assess the achievement of good chemical and ecological status for all water bodies by 2015. This article reviews the potential of biomarkers for ecotoxicological status assessment in WFD monitoring programs. For this purpose, we define the roles and the functions of biomarkers as biomonitoring tools. We also highlight the importance of defining a clear reference system to be confident that biomarkers represent a quantitative assessment of the effects of contaminants

Utilisation des biomarqueurs pour la caractérisation de l'état écotoxicologique des masses d'eau

National audienceIn the past 25 years, numerous biomarkers have been developed with the objective to apply them to aquatic ecosystem biomonitoring. Recently, the Water Framework Directive (WFD) of the European union specified monitoring programs required to assess the achievement of good chemical and ecological status for all water bodies by 2015. This article reviews the potential of biomarkers for ecotoxicological status assessment in WFD monitoring programmes based on previous national and international experiments.Au cours des 25 dernières années, de nombreux biomarqueurs ont été développés dans un objectif de biosurveillance des milieux aquatiques. Récemment, la directive cadre sur l'eau (DCE) de l'Union européenne précisait les programmes de surveillance requis pour évaluer l'atteinte du bon état chimique et écologique des masses d'eau en 2015. En s'appuyant sur les expériences nationales et internationales antérieures, cet article dresse un bilan du potentiel des biomarqueurs pour évaluer le statut écotoxicologique des milieux aquatiques dans le cadre des programmes de surveillance de la DCE

In-vivo experimental model for silicosis : fisher 344, sprague dawley and wistar rat strains

The selection of an experimental model for silicosis requires a thorough understanding of a number of different pulmonary parameters specific to the animal that is to be used (e.g., clearance time, penetration curves, anatomical differences...), and of the sensitivity of the strains that are to be used. The pulmonary response of three rat strains (i.e., Fisher 344, Sprague Dawley, Wistar) to silica dust were compared using two different exposure methods: intra-tracheal injections and inhalation. The test periods lasted 3 months for injection and 6 and 12 months for inhalation. The histological study of the lung revealed a distinct nodular reaction among Sprague Dawley and Wistar strains. Intra-tracheal injections led to the development of fibrotic nodules among Wistar rats, whereas such silicotic nodules were infrequent among injected Fisher 344 rats, and almost absent when exposure was by inhalation. Sprague Dawley and Fisher 344 rats showed frequent thickening and metaplasia of the alveolar walls near the terminal bronchioles. This tendency was particularly pronounced among rats exposed by inhalation (especially among Fisher 344 rats). Evaluation of wet lung weight (i.e., hydroxyproline, lipid and silica lung contents) reveals an increase in the different parameters for Sprague Dawley rats relative to the other two strains, regardless of the type of exposure. It has thus been concluded that Wistar rats are the best experimental model for silicosis, as their pulmonary reaction is more characteristic than that of the other two strains

Effect of prochloraz fungicide on biotransformation enzymes and oxidative stress parameters in three-spined stickleback (Gasterosteus aculeatus L.)

International audienceThe aim of this study was to characterize biomarker responses in three-spined sticklebacks exposed to prochloraz (Pcz). For this purpose, adult sticklebacks were exposed for 2 weeks to prochloraz at 0, 10, 50, 100 and 500 mu g/L prior to one week of depuration in clean water. At days 7, 14 and 21, several hepatic biomarkers were measured including 7-ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT), total glutathione (GSH) content and thiobarbituric acid reactive substances (TBARS). Pcz induced a transient increase of antioxidant enzymes and a depletion of glutathione content during the first 7 days of exposure. This study showed that EROD activity and antioxidants were disrupted in a transient manner. GST was rapidly induced in a dose-dependent manner and this induction was persistent and observed also after depuration. GST appeared as a valuable biomarker to assess the exposure to Pcz

Inhibition of rainbow trout (Oncorhynchus mykiss) P450 aromatase activities in brain and ovarian microsomes by various environmental substances

International audienceAromatase, a key steroidogenic enzyme that catalyses the conversion of androgens to estrogens, represent a target for endocrine disrupting chemicals. However, little is known about the effect of pollutants on aromatase enzymes in fish. In this study, we first optimized a rainbow trout (Oncorhynchus mykiss) microsomal aromatase assay to measure the effects of 43 substances belonging to diverse chemical classes (steroidal and non steroidal aromatase inhibitors, pesticides, heavy metals, organotin compounds, dioxins, polycyclic aromatic hydrocarbons) on brain and ovarian aromatase activities in vitro. Our results showed that 12 compounds were able to inhibit brain and ovarian aromatase activities in a dose-dependent manner with IC50 values ranging from the low nM to the high uM range depending on the substance: steroidal and non steroidal inhibitors of aromatase (4-hydroxyandrostenedione, androstatrienedione, aminogluthethimide), imidazole fungicides (clotrimazole, imazalil, prochloraz), triazole fungicides (difenoconazole, fenbuconazole, propiconazole, triadimenol), the pyrimidine fungicide fenarimol and methylmercury. Overall, this study demonstrates that rainbow trout brain and ovarian microsomal aromatase assay is suitable for evaluating potential aromatase inhibitors in vitro notably with respect to environmental screening. The results highlight that methylmercury and some pesticides that are currently used throughout the world, have the potential to interfere with the biosynthesis of endogenous estrogens in fish

Assessment of seasonal variability of biomarkers in three-spined stickleback (Gasterosteurs aculatus L) from a low contaminated stream : implication for environmental biomonitoring

International audienceIn this study, wild three-spined sticklebacks were sampled every six weeks, between April and October, in a low contaminated stream. For all fish, physiological indexes, such as condition factor, hepato-, gonado- and nephro-somatic index were calculated to determine fish condition and reproductive status. Moreover, a set of biomarkers including biotransformation enzymes, oxidative stress parameters, neurotoxicity and endocrine disruption markers was measured. The results allowed to determine biomarker variability due to fish gender or sampling season. For example, 7-ethoxyresorufin-O-deethylase activity, glutathione peroxidase as well as vitellogenin and spiggin exhibited strong gender differences. Conversely, lipoperoxidation and acethyleholinesterase activity were characterised by a lack of gender and seasonal variation, and can be considered as more robust parameters for a field application. The present work allowed to establish practical guideline for biomarker measurements in wild sticklebacks and to define a reference system which can be used to analyze variations in future monitoring studies

Comparison of two reference systems for biomarker data analysis in a freshwater biomonitoring context

International audienceThe usefulness of fish biomarkers for freshwater biomonitoring is now well recognized, but they still pose several questions to ecotoxicology researchers. The present study, designed to assess the effects of a small city located in an agricultural river basin watershed on sticklebacks living in an adjacent river, underlines the importance of reference selection. Two reference systems were used to analyse responses of a set of biomarkers, including biotransformation enzymes, oxidative stress parameters, neurotoxicity and endocrine disruption end-points, measured in wild sticklebacks electrofished in a contaminated stream. The results showed that the investigated urban pressure disturbed CYP3A activity but also induced hepatic lipoperoxidation and circulating vitellogenine but this result is strongly influenced by the selected reference system. This work therefore demonstrates the need for further research to identify a robust reference system for stickleback biomarker analysis

Preliminary investigation of multi-biomarker responses in three-spined stickleback (Gasterosteus aculeatus L.) sampled in contaminated streams

International audienceRecently, the three-spined stickleback (Gasterosteus aculeatus L.) has been proposed as a suitable fish species for detecting both androgen- and estrogen-induced endocrine disruption by environmental pollutants. This relatively pollution-tolerant fish is present in most European streams and small rivers but also coastal and estuarian areas. The purpose of the present field study was to determine the extent to which multiple biomarkers in this fish species could distinguish between streams with different pollution levels. Sticklebacks were sampled in French rivers characterised by various urban, industrial or agricultural contaminations and in outdoor lotic mesocosms as reference site. Physiological parameters including condition factor and liver somatic index, biotransformation enzymes such as 7-ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase, antioxidant enzymes including glutathione peroxidase and total glutathione (GSH) content and lipoperoxidation (as TBARS) showed several differences between sites. For example, fish from an heavily contaminated stream exhibited a 9-fold EROD induction associated to a decrease of GSH and a 3-fold increase of TBARS content in comparison to fish from uncontaminated sites. When fish were transferred from polluted river to clean water, some of these biomarkers rapidly returned to basal levels found in fish in the reference site while others, like TBARS levels were still high after 2 weeks of depuration. Based on multivariate analyses, the battery of biomarkers proved to differentiate all sites, with a very good classification rate for highly contaminated streams. Influence of fish gender and sampling period on biomarker responses was also observed and is discussed. The results of this field study provide additional support for the use of stickleback for in situ multi-biomarker assessment

Retentissement d'une acidification du milieu sur la glycosylation membranaire de cellules épithéliales de trachée en culture

International audienceLes pluies acides representent une des formes les plus graves de la pollution atmospherique. Elles sont generees essendellement par solubilisation dans l'eau de deux gaz polluants: le S02 qui peut se transformer en acide sulfurique et le dioxide d'azote qui peut generer de l'acide nitrique. Ces acides conferent alors aux precipitations un pH moyen de 3,6 pouvant aller jusqu'a 2 et, de ce fait, contribuent a abaisser le pH de nombreux milieux biologiques. Ceux ci comprennent des ecosystemes entiers (lacs) mais egalement certains tissus humains comme les voies respiratoires. Des etudes ont montre que I'abaissement du pH pouvait jouer un role significatif dans l'alteration de certaines fonctions essentielles pour de nombreuses cellules, en particulier, les cellules epitheliales. Certaines de ces fonctions sont associees ä l'expression membranaire de structures complexes dans lesquelles la partie glucidique est primordiale et, dans ce cas, les acides sialiques sont incrimines

Biochemical effects of nonyphenol polyethoxylate adjuvant, Diquat herbicide and their mixture on the three-spined stickleback (Gasterosteus aculeatus L.)

This study examined the response of 7-ethoxyresorufine-O-deethylase (EROD), glutathioneS-transferase (GST), glutathione peroxidase (GPx), glutathione content (GSH), level of thiobarbituric acid reactive compounds (TBARS) and circulating vitellogenin, in three-spined sticklebacks after 21 days of exposure to Diquat herbicide, commercial nonylphenol polyethoxylate (NPEO) adjuvant and mixture between Diquat and adjuvant. The results showed that adjuvant exerted more important oxidative effects than Diquat and that mixture effects were unlike to single additivity. This study argues for ecotoxicological risk assessment of adjuvants and mixtures of adjuvants and pesticides