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Resultados 2161-2170 de 62,508
On the use of random walk schemes in oil spill modelling Texto completo
2019
Nordam, Tor | Nepstad, Raymond | Litzler, Emma | Röhrs, Johannes
In oil spill models, vertical mixing due to turbulence is commonly modelled by random walk. If the eddy diffusivity varies with depth, failing to take the derivative of the diffusivity into account in the random walk scheme will lead to incorrect results. Depending on the diffusivity profile, the result may be either over- or underprediction of the amount of surfaced oil. The importance of using consistent random walk schemes has been known for decades in, e.g., the plankton modelling community. However, it appears not to be common knowledge in the oil spill community, with inconsistent random walk schemes appearing even in recent publications. We demonstrate and quantify the error due to inconsistent random walk, using a simplified oil spill model, and two different diffusivity profiles. In the two cases considered, a commonly used inconsistent scheme predicts respectively 54% and 202% the amount of surface oil, compared to a consistent scheme. | publishedVersion
Mostrar más [+] Menos [-]The zebrafish embryotoxicity test (ZET) for nanotoxicity assessment: from morphological to molecular approach Texto completo
2019
Pereira, Aryelle Canedo | Gomes, Tânia | Ferreira Machado, Mônica Rodrigues | Rocha, Thiago Lopes
Embargo until 28 June 2021 | Nanotechnology and use of nanomaterials (NMs) improve life quality, economic growth and environmental health. However, the increasing production and use of NMs in commercial products has led to concerns about their potential toxicity on human and environment health, as well as its toxicological classification and regulation. In this context, there is an urgent need to standardize and validate procedures for nanotoxicity testing. Since the zebrafish embryotoxicity test (ZET) has been indicated as a suitable approach for the toxicity assessment of traditional and emergent pollutants, the aim of this review is to summarize the existing literature on embryotoxic and teratogenic effects of NMs on zebrafish. In addition, morphological changes in zebrafish embryos induced by NMs were classified in four reaction models, allowing classification of the mode of action and toxicity of different types of NM. Revised data showed that the interaction and bioaccumulation of NMs on zebrafish embryos were associated to several toxic effects, while the detoxification process was limited. In general, NMs induced delayed hatching, circulatory changes, pigmentation and tegumentary alterations, musculoskeletal disorders and yolk sac alterations on zebrafish embryos. Recommendations for nanotoxicological tests are given, including guidance for future research. This review reinforces the use of the ZET as a suitable approach to assess the health risks of NM exposure. | publishedVersion
Mostrar más [+] Menos [-]Marine microplastic debris: An emerging issue for food security, food safety and human health Texto completo
2018
Barboza, Luís G.A. | Dick Vethaak, A | Lavorante, Beatriz RBO | Lundebye, Anne-Katrine | Guilhermino, Lucia
Recent studies have demonstrated the negative impacts of microplastics on wildlife. Therefore, the presence of microplastics in marine species for human consumption and the high intake of seafood (fish and shellfish) in some countries cause concern about the potential effects of microplastics on human health. In this brief review, the evidence of seafood contamination by microplastics is reviewed, and the potential consequences of the presence of microplastics in the marine environment for human food security, food safety and health are discussed. Furthermore, challenges and gaps in knowledge are identified. The knowledge on the adverse effects on human health due to the consumption of marine organisms containing microplastics is very limited, difficult to assess and still controversial. Thus, assessment of the risk posed to humans is challenging. Research is urgently needed, especially regarding the potential exposure and associated health risk to micro- and nano-sized plastics. | publishedVersion
Mostrar más [+] Menos [-]Study of the oil interaction towards oil spill recovery skimmer material: Effect of the oil weathering and emulsification properties Texto completo
2018
Farooq, Umer | Taban, Ingrid Christina | Daling, Per Snorre
The primary aim of this research was to identify the physicochemical properties of the oil and water-in-oil (W/O) emulsions used during a NOFO Oil-on-Water field trials that reduced the performance of the skimmers recovery efficacy during the trials. Extensive studies were performed at SINTEF laboratories with the residues of oil topped (i.e. evaporative loss of crude oil components by distillation process at large scale) for the field trial and compared it with different residues of oil topped by bench scale laboratory procedures. In order to obtain a sufficient stable W/O emulsion for the field trial, bunker fuel oil (IFO380) and various concentrations of an emulsifier (Paramul®) were also added to the residues of oil topped on large scale and investigated through interfacial tension, contact angle, droplet adhesion and “dip and withdraw” tests. The investigations revealed that the addition of an emulsifier lowered the interfacial tension of oil residues, which consequently reduced the adherence properties of the oil and emulsions to the surface of the skimmer material. Too high concentration of an emulsifier (>0,5%) also had a negative effect on the stability of W/O emulsion. | Study of the oil interaction towards oil spill recovery skimmer material: Effect of the oil weathering and emulsification properties | acceptedVersion
Mostrar más [+] Menos [-]Ecological risk assessment to marine organisms induced by heavy metals in China's coastal waters Texto completo
2018
Wang, Mengzhu | Tong, Yindong | Chen, Cen | Liu, Xianhua | Lu, Yiren | Zhang, Wei | He, Wei | Wang, Xuejun | Zhao, Shen | Lin, Yan
Embargo until 23 November 2019 | China's coastal environment has been heavily affected by the loading of terrestrial pollutants in recent decades, and quantitative risk assessment is urgently needed to assess the ecological risks of China's coastal environment. We assessed the ecological risks induced by five heavy metals (including Cu, Zn, Pb, Hg and As) in China's coastal waters for three groups of marine organisms (including crustacean, fish and mollusc) based on data obtained from a nationwide unified coastal environment monitoring program consisting of 301 sampling sites. The results show that higher heavy metal concentrations occurred more frequently in the Bohai Sea and in the estuaries of major sea-going rivers. The ecological risks decreased in the following order: Bohai Sea > Yellow Sea > South China Sea > East China Sea. There was generally low ecological risk, but certain hotspots existed near Tianjin and Jinzhou, which had relatively high ecological risks caused by Cu and Zn. | acceptedVersion
Mostrar más [+] Menos [-]Assessing impacts of simulated oil spills on the Northeast Arctic cod fishery Texto completo
2017
Carroll, JoLynn | Vikebø, Frode Bendiksen | Howell, Daniel | Broch, OJ | Nepstad, Raymond | Augustine, Starrlight | Skeie, Geir Morten | Bast, Radovan | Juselius, Jonas
We simulate oil spills of 1500 and 4500 m3/day lasting 14, 45, and 90 days in the spawning grounds of the commercial fish species, Northeast Arctic cod. Modeling the life history of individual fish eggs and larvae, we predict deviations from the historical pattern of recruitment to the adult population due to toxic oil exposures. Reductions in survival for pelagic stages of cod were 0–10%, up to a maximum of 43%. These reductions resulted in a decrease in adult cod biomass of < 3% for most scenarios, up to a maximum of 12%. In all simulations, the adult population remained at full reproductive potential with a sufficient number of juveniles surviving to replenish the population. The diverse age distribution helps protect the adult cod population from reductions in a single year's recruitment after a major oil spill. These results provide insights to assist in managing oil spill impacts on fisheries. | publishedVersion
Mostrar más [+] Menos [-]DECOMBIO - Contribution de la combustion de la biomasse aux PM10 en vallée de l’Arve : mise en place et qualification d’un dispositif de suivi Texto completo
2016
Chevrier, Florie | JEžEK, Irena | Brulfert, Guillaume | MOčnik, Grisa | Marchand, Nicolas | Jaffrezo, Jean-Luc | Besombes, Jean-Luc
Les espaces périurbains : entre pollution des villes et pollution des champs aux échelles régionale et locale Texto completo
2016
Stella, Patrick | Bedos, Carole | Génermont, Sophie, | Loubet, Benjamin | Personne, Erwan | Petit, Caroline, | Saint-Jean, Sébastien
Les espaces périurbains : entre pollution des villes et pollution des champs aux échelles régionale et locale Texto completo
2016
Stella, Patrick | Bedos, Carole | Génermont, Sophie, | Loubet, Benjamin | Personne, Erwan | Petit, Caroline, | Saint-Jean, Sébastien
Les territoires périurbains, zones de transition entre les zones urbaines et rurales, sont soumis à de nombreuses pollutions à la fois gazeuses et particulaires. Ces pollutions proviennent de sources locales comme les activités résidentielles, le trafic routier et les activités agricoles, mais également de sources régionales issues des activités urbaines et des émissions des zones (pseudo-)naturelles adjacentes. Cet article présente une synthèse des différentes sources de pollution affectant la qualité de l’air en milieu périurbain. Il est évident que les pollutions purement anthropiques ne peuvent être dissociées de celles issues du fonctionnement des écosystèmes (pseudo-)naturels dans ces espaces. Enfin, les enjeux vis-à-vis de l’agriculture périurbaine, fortement présente et en développement du fait d’une volonté de consommer des productions locales, sont discutés. | Periurban areas, zone of transition between urban and rural areas, are submitted to several sources of pollution, both gaseous and particulate. These pollutions originate from local sources such as residential sector, traffic road and agricultural activities, but also from regional ones from adjacent urban and (pseudo-)natural areas. This paper presents a synthesis of the different sources affecting air quality in periurban areas. It is clear that pollutions from anthropogenic activities cannot be fully dissociated to those from (pseudo-)natural ecosystem functioning in these areas. Finally, the atmospheric pollution issues are discussed in emphasis with periurban agriculture, already present and under development in these areas due to the development of short food supply chains and local food consumptions.
Mostrar más [+] Menos [-]Les espaces périurbains : entre pollution des villes et pollution des champs aux échelles régionale et locale Texto completo
2016
Stella, Patrick | Bedos, Carole | Génermont, Sophie | Loubet, Benjamin | Personne, Erwan | Petit, Caroline | Saint-Jean, Sébastien | Sciences pour l'Action et le Développement : Activités, Produits, Territoires (SADAPT) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech | Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech
International audience | Periurban areas, zone of transition between urban and rural areas, are submitted to several sources of pollution, both gaseous and particulate. These pollutions originate from local sources such as residential sector, traffic road and agricultural activities, but also from regional ones from adjacent urban and (pseudo-)natural areas. This paper presents a synthesis of the different sources affecting air quality in periurban areas. It is clear that pollutions from anthropogenic activities cannot be fully dissociated to those from (pseudo-)natural ecosystem functioning in these areas. Finally, the atmospheric pollution issues are discussed in emphasis with periurban agriculture, already present and under development in these areas due to the development of short food supply chains and local food consumptions. | Les territoires périurbains, zones de transition entre les zones urbaines et rurales, sont soumis à de nombreuses pollutions à la fois gazeuses et particulaires. Ces pollutions proviennent de sources locales comme les activités résidentielles, le trafic routier et les activités agricoles, mais également de sources régionales issues des activités urbaines et des émissions des zones (pseudo-)naturelles adjacentes. Cet article présente une synthèse des différentes sources de pollution affectant la qualité de l’air en milieu périurbain. Il est évident que les pollutions purement anthropiques ne peuvent être dissociées de celles issues du fonctionnement des écosystèmes (pseudo-)naturels dans ces espaces. Enfin, les enjeux vis-à-vis de l’agriculture périurbaine, fortement présente et en développement du fait d’une volonté de consommer des productions locales, sont discutés.
Mostrar más [+] Menos [-]L’agriculture entre pollution atmospherique et changement climatique Texto completo
2016
Cellier, Pierre | Génermont, Sophie,
Les agroécosystèmes sont des sources et des puits de polluants atmosphériques et de gaz à effet de serre et, par là-même, ils interviennent dans les relations entre climat et pollution de l’air. Cette contribution, positive ou négative, résulte de processus complexes, à la fois directs et indirects, et prend des formes très diverses : augmentation ou diminution des émissions et dépôts, augmentation attendue de la fréquence des feux, modification de la protection phytosanitaire etc. Comme pour la plupart des processus biologiques, les incertitudes sont importantes et les verrous de connaissances restent nombreux, alors qu’une connaissance des différents facteurs d’influence, naturels et anthropiques est nécessaire pour limiter la contribution des agroécosystèmes à la fois au changement climatique et à la pollution de l’air, tout en préservant les performances économiques de l’activité agricole. Enfin, l’agriculture est concernée par tout un ensemble de politiques publiques relatives au changement climatique et à la pollution de l’air, mais également à la pollution des eaux et à la protection de l’environnement, politiques publiques qui peuvent interagir en synergie ou être antagonistes. | Interactions between climate change and air pollution in the context of agriculture. Agroecosystems are sources and sinks of atmospheric pollutants and greenhouse gases. They are therefore involved in climate change and air pollution and their cross-relations. This contribution can be positive or negative. It results from complex processes, both direct and indirect, which is related to a range of topics: increase or decrease of emission and deposition, increase in fire frequency, change in plant protection etc. As for most of biological processes, there are large uncertainties and knowledge is lacking over a range of fields. However it is necessary to have a global overview of the involved processes and drivers when trying to limit the contribution of agroecosystem both to climate change and air pollution, with attention to the economic sustainability of agriculture under global change. Moreover agriculture activities refer to public policies related not only to climate change and air pollution but also water pollution or protection of the environment. These policies may interact positively or be antagonist.
Mostrar más [+] Menos [-]Synthèse des connaissances sur le transfert des pesticides vers l’atmosphère par volatilisation depuis les plantes Texto completo
2015
Lichiheb, Nebila | Bedos, Carole | Personne, Erwan | Barriuso, Enrique
Les niveaux de concentration des pesticides dans l’atmosphère méritent une attention particulière de la part de la recherche compte tenu de leurs impacts potentiels sur la population et les écosystèmes. L’activité agricole constitue la principale source de contamination de l’atmosphère par les pesticides. Bien que la volatilisation depuis la plante soit reconnue plus intense et plus rapide que la volatilisation depuis le sol, cette voie de transfert est à ce jour la moins bien renseignée avec peu de modèles disponibles pour sa description. Le manque de connaissances est lié essentiellement à la complexité des interactions entre les processus ayant lieu à la surface de la feuille et qui sont en compétition avec la volatilisation, notamment la pénétration foliaire et la photodégradation. Cet article présente une synthèse bibliographique sur l’état des lieux des connaissances sur le processus de volatilisation des pesticides depuis un couvert végétal, de la pénétration foliaire et de la photodégradation, ainsi que les facteurs de contrôle de ces processus. Les méthodes de mesure ainsi que les modèles existants décrivant ces processus sont également présentés et analysés | The agricultural activity presents the main source of the atmospheric contamination by pesticides. The occurrence of pesticides in the atmosphere concerns the research community due to their potential impacts on population and ecosystems. The volatilization from plants is higher and faster than the volatilization from soil. However, this transfer pathway is difficult to assess with few available models. The lack of knowledge on pesticide volatilization from plants is essentially linked to the complex interactions between processes occurring at the leaf surface and competing with volatilization, such as leaf penetration and photodegradation. This article presents a bibliographic synthesis of the state of knowledge on pesticide volatilization from plants, leaf penetration, photodegradation and control factors of these processes. Measuring methods and existing models describing these processes are also presented and analyzed
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