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

Perspectives from the French workshop on the development and validation of biomarkers and bioassays for the monitoring of aquatic environments

International audienceDuring the past three decades, there has been an increasing interest in the field of ecotoxicology for development of effect-based monitoring tools (EBMTs) including in vitro tests, biomarkers and whole organism bioassays. This interest is due to the practical application of EBMTs in the surveillance of the quality of water and aquatic ecosystems (ICES, 2008). Within this framework, these ecotoxicological tools seem to offer numerous potential advantages, as they allow one to take into account the cumulative impact of the whole contaminants present in the field, and the bio-available and active fractions of toxicants as well as their degradation bioaccumulation, biotransformation (Lam and Gray, 2003; Hecker and Hollert, 2009). Hence, they are often seen as complementary tools to conventional environmental monitoring approaches, mostly based on the measurement of a predefined list of chemical substances in various aquatic compartments (water, sediments and biota) and the analyses of indices of biological integrity (OSPAR 2004). Due to these research activities, several core EBMTs (SGIMC, 2011) are now well characterised and may be directly used to assess the quality of the aquatic environment under a European consensus (Table 1; Sanchez and Porcher, 2009; Lyons et al., 2010). However, if EBMTs are widely used in research studies and provide, at geographically and temporally limited scales, data on ecotoxicological status of water bodies, few applications of EBMTs are currently implemented in regulatory environmental monitoring programs

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

Are biochemical biomarker responses related to physiological performance of juvenile sea bass (Dicentrarchus labrax) and turbot (Scophthalmus maximus) caged in a polluted harbour ?

International audienceBiomarker responses to toxic exposure have been used for decades to indicate stress in aquatic organisms, or the magnitude of environmental pollution. However, little has been done to compare the simultaneous responses of both biochemical and physiological biomarkers. The purpose of this study was twofold. Firstly to analyse the responses of several biochemical biomarkers measured on juvenile sea bass and turbot caged in a northern France harbour at a reference and contaminated stations. Several biotransformation parameters (Ethoxyresorufin-O-deethylase - EROD - and Glutathione S-transferase -GST) and an antioxidant enzyme (Catalase -CAT) were analysed. Secondly, to compare their responses to several growth and condition indices, measured on the same fish. In the contaminated station, EROD and GST activities were found to be significantly higher, and a decrease of CAT activity was observed for both species. For individual sea bass, biochemical biomarkers showed numerous significant correlations with growth and condition indices, such as the Fulton's K condition index, the RNA:DNA ratio and the lipid storage index. On the contrary, there were only a few significant correlations for turbot, suggesting a species-specific response. Our study indicates that the analysis of the simultaneous responses of both biochemical and physiological biomarkers can be useful for monitoring complex exposure and to assess habitat quality

Lubrication analysis of peristaltic motion in non-axisymmetric annular tubes

This paper addresses peristaltic flow induced in a non-axisymmetric annular tube by a periodic small-amplitude wave of arbitrary shape propagating axially along its inner surface, assumed to be a circular cylinder. The study is motivated by recent in vivo experimental observations pertaining to the flow of cerebrospinal fluid along the perivascular spaces of cerebral arteries. The analysis employs the lubrication approximation, describing low-Reynolds-number peristaltic flow in the long-wavelength approximation. Closed-form analytic expressions are derived for the average pumping rate in infinitely long tubes and also in tubes of finite length. Consideration is also given to the transverse motion arising in non-axisymmetric tubes. For small-amplitude waves, the solution is reduced to the integration of a parameter-free Stokes-flow problem, which is solved for relevant cross-sectional shapes, with closed-form analytical results derived for thin canals

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

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

Liver antioxidant and plasmatic immune responses in juvenile golden grey mullet (Liza aurata) exposed to dispersed crude oil

International audienceDispersant application is an oil spill response technique. To evaluate the environmental cost of this operation in nearshore habitats, the experimental approach conducted in this study exposed juvenile golden grey mullets (Liza aurata) for 48 hours to chemically dispersed oil (simulating, in vivo, dispersant application), to dispersant alone in sea water (as an internal control of chemically dispersed oil), to mechanically dispersed oil (simulating, in vivo, natural dispersion), to the water-soluble fraction of oil (simulating, in vivo, an oil slick confinement response technique) and to sea water alone (control condition). Biomarkers such as fluorescence of biliary polycyclic aromatic hydrocarbon (PAH) metabolites, total glutathione liver content, EROD (7-ethoxy-resorufin-O-deethylase) activity, liver antioxidant enzyme activity, liver lipid peroxidation and an innate immune parameter (haemolytic activity of the alternative complement pathway) were measured to assess the toxicity of dispersant application. Significant responses of PAH metabolites and total glutathione liver content to chemically dispersed oil were found, when compared to water-soluble fraction of oil. As it was suggested in other studies, these results highlight that priority must be given to oil slick confinement instead of dispersant application. However, since the same patterns of biomarkers responses were observed for both chemically and mechanically dispersed oil, the results also suggest that dispersant application is no more toxic than the natural dispersion occurring in nearshore areas (e.g. waves). The results of this study must, nevertheless, be interpreted cautiously since other components of nearshore habitats must be considered to establish a framework for dispersant use in nearshore areas

Functional significance of genotoxicity in fish germ cells

The aquatic environment is becoming increasingly contaminated by pollutants having a genotoxic potential towards organisms and in particular in fish. Such genotoxins are prone to affect directly offspring or indirectly through the reproductive process. All this could influence recruitment rate and hence the population dynamics. However, assessment of the ecological risks associated with environmental genotoxic exposure is usually based on individual responses. Thus, there is a need for a better understanding of the long term and population level implications of genotoxic insults in fish. While low levels of DNA damage in somatic cells and oocytes can be efficiently repaired, mature sperm cells, i.e. spermatozoa, are susceptible to accumulate damage due to their lack of repair capacity. The present work aims to track the transfer of toxic effects across generations by studying the link between the level of DNA damage in fish sperm, and the rate of development abnormalities measured in the offspring after parental exposure to the model genotoxicant MMS. Three different fish species were chosen based either on their ecological importance or on their reproduction behavior, respectively brown trout (Salmo trutta), Arctic charr (Salvelinus alpinus) and threespine stickleback (Gasterosteus aculeatus). Results show a significant increase in sperm DNA damage measured with the comet assay in exposed organisms. This damage did not impact on fertilization success but led further to a significant increase in embryo abnormality rate at early embryonic and late larval stages, and further delayed growth in exposed group compared to the control