Helene Thomas

Helene Thomas
La Rochelle Université · biology

About

37
Publications
2,427
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120
Citations

Publications

Publications (37)
Article
The characterization of organic and inorganic environmental pollution in coastal ecosystems, such as port areas, is complex and difficult to carry out due to the effect of environmental variables, as well as anthropic activities. For this study, the objective was to define a statistical method, taking into account the confounding factors influence,...
Article
The seasonal pattern of microplastics (MPs) contamination of the French littoral area of the Pertuis Charentais, one of the main French shellfish production regions, was assessed for the first time, between May 2019 and May 2020 at four different sites. The reference site was located at “Ile de Ré” and the other sites were located in the estuaries...
Poster
Full-text available
Coastal port areas are subjected to a myriad of pollution sources. Contaminants in such systems include legacy pollutants (metals and hydrocarbons) and emerging contaminants (e.g. pharmaceuticals) with largely unknown effects. Monitoring for such complex chemical mixtures in marine ecosystems is difficult. Transcriptomics is a promising approach ap...
Poster
Full-text available
Les pollutions présentes en mer (organiques et inorganiques), proviennent à plus de 80% du domaine terrestre et des activités humaines qui y sont menées. Les eaux côtières, regroupant pas moins de 90% de la biodiversité marine, sont directement impactées par ces pressions anthropiques. Plus particulièrement, les zones portuaires, qui abritent bons...
Article
A qualitative screening high resolution mass spectrometry method was developed and validated according to the EU SANTE/12682/2019 guidelines for the analysis of 204 pesticides in seven commercial bivalve species spiked at three concentrations (0.01, 0.05 and 0.1 mg.kg⁻¹). Samples were extracted using QuEChERS and analysed using ultra-high-performan...
Article
This study focused on the impacts of aged aquaculture microplastics (MPs) on oysters (Crassostrea gigas). Adult oysters were exposed for two months to a cocktail of MPs representative of the contamination of the Pertuis Charentais area (Bay of Biscay, France) and issuing from oyster framing material. The MPs mixture included 28% of polyethylene, 40...
Poster
Full-text available
Le biomonitoring du milieu marin, mis en place pour caractériser l’état écologique d’un milieu, ou évaluer les effets des protocoles de gestion environnementale, permet le développement d'une compréhension scientifique de l'environnement marin et des impacts des humains sur celui-ci. Les méthodes traditionnelles de biomonitoring sont généralement b...
Article
The present pilot study aimed to provide an overview of organic contaminant concentration levels in the littoral ecosystems of the Pertuis seas. The study determined the concentrations of twenty-nine pesticides, six nonylphenols and seven polybrominated diphenyl ethers (PBDEs) in sediments, seawater, Pacific oysters and blue mussels. Oysters accumu...
Chapter
In this chapter, the authors examine and observe the presence of invasive copepods in Pertuis Charentais seawater under controlled laboratory conditions. During an experiment carried out on adult oysters, reared in an aquarium with seawater from Pertuis Charentais and exposed to environmental microplastics, they were able to observe a large number...
Presentation
Full-text available
Dans les zones portuaires, les divers polluants retrouvés dans le milieu constituent une menace sérieuse pour le milieu marin et les espèces qui y résident [1]. Les activités récréatives, le trafic maritime, le carénage, etc. provoquent une contamination qui s'ajoute à celle déjà observée en zone côtière. Ces pressions anthropiques chroniques peuve...
Chapter
Several research studies focused on improving the quality of port areas using filter feeder organisms such as black scallops Mimachlamys varia , collecting dissolved particles. In this respect, for three years this study aimed to monitor biological and physiological quality and assesses the suitability of the measures taken by the La Rochelle harbo...
Chapter
Research on adult M. varia revealed a rapid bioaccumulation of heavy metals and a similar toxicity to previous studies carried out in situ in the La Rochelle marina. Juvenile scallops were used as an indicator species to assess the diffusion of pollution in harbor environments. This chapter aims to observe the impact of inorganic chemical contamina...
Chapter
Like many other large ecosystems worldwide, the water of the French Atlantic coastline is subject to diverse anthropogenic pressures (overfishing, climate change, loss of biodiversity and habitats, and chemical pollution because of phytosanitary, organic and inorganic contaminants). Biomonitoring programs follow marine pollution and marine resource...
Chapter
Human activities, whether at sea, on land or along the human‐made coastline may cause chronic and diffuse pollution in the marine environment that represents 75% of the global marine pollution. The use of bioindicators is particularly relevant from a biological point of view if the directly measured concentrations reflect the bioavailable fractions...
Chapter
The coastal area of the Charente‐Maritime region is highly attractive and is mainly used for economic and recreational activities. The Pertuis Charentais, which are the receptacle of three rivers (the Sèvre‐Niortaise, the Charente and the Seudre) create a good natural environment for shellfish farming. Given the importance of its coastal activities...
Article
Plastic is currently used in aquaculture as a material for settlement and magnification of oyster spats. Plastic weathering and fragmentation under natural conditions can lead to the production of micro and nanoparticles and additive leakage, with potential toxic effects on marine life. This study investigates the effects of the exposure to micropl...
Presentation
Full-text available
Les zones portuaires sont des socio-écosystèmes anthropisés soumis à l’influence des bassins versants et à une forte urbanisation. Ces environnements semi-fermés sont impactés par des polluants (organiques et inorganiques) liés à la dynamique spécifique des ports (trafic maritime, activités de pêche, plaisance, peintures antisalissures). Malgré ces...
Article
Nowadays, pesticides and microplastics (MPs) are commonly found in coastal waters worldwide. Due to their widespread use, their persistence and toxicity, they may induce adverse effects on physiology and behaviour of marine organisms such as the Pacific oyster (Crassostrea gigas). This study explored the growth and valve activity of juvenile oyster...
Article
In the early 1970s, studies of marine litter first appeared in the scientific literature. Fifty years later, knowledge of several coastal areas of the Atlantic, the driving forces of oyster farmers and aquaculture, is lacking. This work documents a pilot study on an Atlantic coastal area (France). This study aims to (i) characterize the abundance o...
Article
This study aims to assess the toxic effects and the potential risk of widely used agricultural pesticides on the development (malformations and developmental arrest), growth and swimming activity of oyster D-larvae (Crassostrea gigas). Freshly fertilized oyster embryos were exposed for 24 h at 24 °C to different concentrations (0, 0.01, 0.1, 1 and...
Poster
Full-text available
In this study, a 25-day exposure was set up on juvenile oysters (C. gigas) to various contaminants potentially present in the natural marine environment. Four conditions were tested: control (without pollutants), polyethylene (20-25 µm, 10 µg.L-1) microplastics (MPs), chlortoluron (herbicide, 30 µg.L-1) and cocktail mixture (MPs + chlortoluron). Tw...
Article
Full-text available
The development of human activities along the Atlantic coast (France) is responsible for the chronic pollution of the environment with organic (pesticides, hydrocarbons, phytosanitary) and inorganic (metals) contaminants. In recent years, environmental regulations such as the Marine Strategy Framework Directive (MSFD, 2008/56/EC) and the OSPAR comm...
Poster
Full-text available
Coastal areas are the interface between terrestrial and marine ecosystems and are a habitat for 90% of the marine biodiversity. However, these waters are the first impacted by anthropic activities, especially in port areas, due to the maritime traffic or accidental pollution. Following the recommendations of the Marine Strategy Framework Directive,...
Poster
Full-text available
To better understand the potential effect of microplastics (MPs) on the marine environment, we are interested in this work on the impact of environmental microplastics in the shellfish industry on the oyster (Crassostrea gigas) model. In this study, we exposed for two months adult oysters to a cocktail of environmental microplastics (polyethylene,...
Poster
Full-text available
Le projet AQUAECOs (Amélioration de la QUAlité Environnemental en zones COnchylicoles) porté par le CRC (Comité Régional Conchylicole Charente-Maritime) est mené en partenariat avec l’AFB (Agence Française pour la Biodiversité), la Région Nouvelle-Aquitaine, le Comité Départemental de la Charente Maritime ; il vise à étudier les effets de stress na...
Poster
Full-text available
This study evaluates the effects of two contaminants (copper and microplastics) on the early stages of development of Pacific oyster Magallana gigas. Three different microplastics (MP) sizes were used (4-6μm ; 11-13μm and 20-25μm). The microplastics used are polyethylene (PE).The mature genitors are obtained in commercial hatcheries (France Naissai...
Presentation
See : Bringer, A., Cachot, J., Prunier, G., Dubillot, E., Clérandeau, C., & Thomas, H. (2020). Experimental ingestion of fluorescent microplastics by pacific oysters, Crassostrea gigas, and their effects on the behaviour and development at early stages. Chemosphere, 126793.
Poster
Full-text available
Le projet AQUAECOs (Amélioration de la QUAlité Environnemental en zones COnchylicoles) porté par le CRC (Comité Régional Conchylicole Poitou-Charentes) et l’AFB (Agence Française pour la Biodiversité) vise à obtenir une meilleure compréhension des effets des micro-nanoplastiques et des pesticides sur les zones de productions conchylicoles des Pertu...
Article
This is a pioneering study in the ecotoxicological assessment of immunotoxic effects of the three selected drugs of concern to a freshwater gastropod species. Lymnaea stagnalis was exposed in the laboratory for 3 days to three drugs used for immune systems: diclofenac (nonsteroidal anti-inflammatory drug), cyclophosphamide (anti-cancer immunosuppre...
Article
The first part of the study was devoted to test the hypothesis according to which the hemolymph of Lymnaea stagnalis can be collected repeatedly - regardless the time-intervals - at an individual scale without impact on survival nor immunocapacity defined as the hemocyte density and viability. No significant effects on snail survival were observed...
Conference Paper
Full-text available
Dispersants are known to be an appropriate solution for offshore spill response when dilution conditions are high and dispersed oil concentrations decrease rapidly below levels that could potentially harm the environment. In coastal areas, however, where dilution can be restricted due to limited depth and vicinity to various coastal resources, disp...
Article
In the present study, we demonstrate that a substituted soluble dextran derivative bearing 73% carboxylic groups and 15% benzylamide sulfonate groups, termed CMDBS25, inhibits complement activation and complement-mediated damage in an in vitro model of xenogeneic rejection. Incubation of porcine aortic endothelial cells with normal human serum resu...
Article
A soluble dextran derivatized with carboxylic groups (73%) and benzylamide sulphonate groups (15%), termed CMDBS 25, exhibited significant anticomplementary activity in the absence of anticoagulant activity. The polysaccharide inhibited both classical and alternative pathway-dependent complement activation in human and rat serum in vitro. Simultane...

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