Usefulness of Bioindicators and Biomarkers in Pollution Biomonitoring

We have different possibilities and tools to assess the impact of pollution on marine ecosystems. The ecotoxicological approaches are based on the use of biomonitors and biomarkers. They aim to study the effect of toxic chemicals on the biological organisms especially at the population, community and ecosystem levels. The ultimate goal of ecotoxicology is to be able to predict the effects of pollution so that the most efficient and effective action to prevent or remediate any detrimental effect.In order to assess the impact of anthropogenic activities on the aquatic ecosystem and to insure compliance with regulation or guidelines, we use biomonitoring. This kind of approach is based on the use of biological responses in order to assess anthropogenic changes in the environment. Biomonitoring involves the use of indicator species such as filter feeding mollusk bivalves. These organisms tend to accumulate pollutants in their tissues without showing any apparent detrimental effect. Moreover, they could reflect the real bio available fraction of the pollutant. In order to have an early warning system predicting the pollution effects even at low levels, biomarkers were extensively studied. Some of them were validated in both field and in vivo conditions.In the present paper, the usefulness of bioindicators and biomarkers in pollution monitoring are discussed. An overview of results from case studies dealing with in situ, in vivo and transplantation experiments is presented

Effects of fluoride on primary cultured haemocytes from the marine gastropod Haliotis tuberculata

International audienceAs a consequence of human's activities, fluoride concentration in many aquatic ecosystems is significantly increasing. Nevertheless, little is known about fluoride toxicity to aquatic life. In this study the effect of exposure to different concentrations of sodium fluoride (2, 10, 50, 250 and 1,250 μg mL −1) during 24 h on primary cultured haemocytes of the gastropod Haliotis tuberculata was realized. Results indicate no significant effect of NaF on cell viability, Lysosomal membrane stability, phagocytosis and ROS production at concentrations of 2, 10, 50 and 250 μg mL −1. Nevertheless, lysosomal membrane alterations, a decrease of phagocytosis and morphological changes of H. tuberculata haemocytes were observed at concentration of 1,250 µg mL −1 NaF suggesting a potential impact of NaF at high concentration in the environment

Effets de la contamination in situ (golfe de Gabès) par le cadmium sur la synthèse des métallothionéines et sur le potentiel reproducteur de la palourde Ruditapes decussatus

Notre étude a porté sur la bioaccumulation in situ du Cd chez la palourde, et ses effets sur leur potentiel reproducteur, dans deux sites du golfe de Gabès: " El Hofra " fortement contaminé et " Bordj d'Ungha " moins impacté. Les palourdes d'El Hofra présentent les concentrations en Cd les plus fortes, avec des fluctuations saisonnières reflétant le phénomène de dilution biologique, essentiellement lié au stade de développement des gonades. Les concentrations en Cd et en métallothionéines (MTs) sont plus élevées dans la glande digestive que dans les branchies. Elles y sont significativement corrélées pour les palourdes des deux sexes d'El Hofra, et pour les mâles de Bordj d'Ungha. L'étude des cycles reproducteurs a révélé un retard de la maturité des gamètes chez les femelles du site contaminé. Cd pourrait perturber l'activité des gonades en créant un déséquilibre hormonal. Le décalage avec la période de maturité des mâles pourrait influer sur le potentiel reproducteur de l'espèce.Our study related to the in situ bioaccumulation of Cd in the clam, and its effects on their reproductive potential, in two sites of the gulf of Gabès: "El Hofra" strongly contaminated and "Bordj d'Ungha" less impacted. The clams from El Hofra present the strongest Cd concentrations, with seasonal fluctuations reflecting the phenomenon of biological dilution, primarily related to the stage of development of gonads. The concentrations of Cd and metallothioneins (MTs) are higher in digestive gland than in the gills. They are significantly correlated in the digestive gland for the clams of the two sexes from El Hofra, and for the males from Bordj d'Ungha. The study of the reproductive cycles revealed a delay of the maturity of the gametes in the females of the contaminated site. Cd could disturb the activity of the gonads by creating an hormonal imbalance. The shift with the period of maturity of the males could influence the reproductive potential of this species.NANTES-BU Médecine pharmacie (441092101) / SudocSudocFranceF

Variation of metallothioneins in gills of the clam Ruditapes decussatus from the Gulf of Gabès (Tunisia)

Cadmium (Cd) and metallothionein (MT) concentrations were determined in the subcellular fractions of the gills of the clam Ruditapes decussatus. Clams were collected monthly during the period of sexual development (from June to August 2001) from two different sites situated in the Gulf of Gabès (Tunisia). These sites differ by their degree of metal contamination. Differences in condition index (CI) were observed in June and August between clams from both sites. In clams from both sites, cadmium was approximately equally distributed between the soluble (S1) and insoluble (C1) fractions. MT levels varied according to month but not sex. Site and body mass of clams seem to be important factors to explain the variation of MT levels compared to cadmium.info:eu-repo/semantics/publishedVersio

A pilot study of genetic differentiation between two phenotypes of a Mediterranean population of the bivalve Cerastoderma glaucum and genetic discrimination with other Cerastoderma glaucum and Cerastoderma edule populations outside the Mediterranean

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