Affiner votre recherche
Résultats 2101-2110 de 62,084
La mesure des polluants…vers la démesure ?
2016
Camel, Valérie
La mesure des polluants…vers la démesure ?. Pollution chimique : la santé en jeu
Afficher plus [+] Moins [-]Conséquences des pollutions atmosphériques sur l'agriculture et la forêt
2014
Castell, Jean-François
Conséquences des pollutions atmosphériques sur l'agriculture et la forêt. Séminaire Agriculture et pollution de l’air
Afficher plus [+] Moins [-]The Air Quality in African Rural Environments. Preliminary Implications for Health: The Case of Respiratory Disease in the Northern Benin
2014
De Longueville, Florence | Hountondji, Yvon-Carmen | Ozer, Pierre | Henry, Sabine
peer reviewed | Recently, the World Health Organization’s International Association for Research on Cancer classified outdoor air pollution as carcinogenic to humans and puts air pollution in the same category as tobacco smoke, UV radiation, and plutonium. The ambient air is polluted by emissions from motor vehicles, industrial processes, power generation, household combustion of solid fuel, and other sources. Dust storms lead to particulate levels that exceed internationally recommended levels, especially near the Sahara. However, this source of air pollution appears to be under-studied, particularly in the literature devoted to human health impacts in West Africa. More than 50 % of the total dust emitted into the atmosphere comes from the Sahara. These aerosols contribute to increase the concentrations of particles smaller than 10 μm (PM10), which are breathable particles. This study is the first designed to assess the real impact of Saharan dust on air quality and respiratory health of children in a region of West Africa. Dust events having affected the Northern Benin during the dry seasons between 2003 and 2007 were determined. The analyzed health data are the monthly rates of acute lower respiratory infections (ALRI). Over the entire study period, 61 days of dust events were observed in the region. They recorded on average a daily PM10 concentration of 1017 μg m−3, more than 18 times higher than that calculated on all days without dust events. The study also highlighted a mean increase of 12.5 % of ALRI rates during the months recording dust events. The use of daily health data should help to refine these initial results in the future.
Afficher plus [+] Moins [-]Contribution de la combustion de biomasse sur les niveaux de PM10 dans la Vallée de l’Arve
2014
Chevrier, F. | Močnik, G. | Brulfert, G. | Laurent, J.-P. | Jaffrezo, J.-L. | Besombes, Jean-Luc
Le premier "ozonetum" d'Europe au Centre de Recherches INRA de Nancy
2004
Garrec, Jean-Pierre,
Dynamics of mercury stable isotope compounds in Arctic seals: new insights from a controlled feeding trial on hooded seals Cystophora cristata.
2024
Pinzone, Marianna | Amouroux, David | Tessier, Emmanuel | Acquarone, Mario | Siebert, Ursula | Das, Krishna | FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
peer reviewed | Accurate interpretation of mercury (Hg) isotopic data requires the consideration of several biotic factors such as age, diet, geographical range, and tissue metabolic turnover. A priori knowledge of prey-predator isotopic incorporation rates and Hg biomagnification is essential. This study aims to assess Hg stable isotopes incorporation in an Arctic species of Phocidae, the hooded seal Cystophora cristata, kept in human care for 24 months (2012 - 2014) and fed on a constant diet of Norwegian Spring Spawning herring Clupea harengus. We measured THg, MMHg and iHg levels, as well as Hg stable isotope composition with both mass dependent (MDF) and mass independent (MIF) fractionation (e.g. δ202Hg and Δ199,200,201,204Hg) in hooded seal kidney, liver, hair and muscle, in addition to herring muscle. We then calculated Hg MDF and MIF isotopic fractionation between hooded seals and their prey. We found a significant shift in δ202Hg between hooded seal hair (+0.80‰) and kidney (-0.78‰), and herring muscle. In hooded seals tissues δ202Hg correlated positively with MMHg percentage. These findings suggest that tissue-specific Hg speciation is the major driver of changes in Hg isotopic fractionation rates in this Arctic predator. Δ199Hg, Δ200Hg, Δ201Hg and Δ204Hg values did not vary between herring and hooded seal tissues, confirming their utility as tracers of Hg marine and atmospheric sources in top predators. To our knowledge, this represents the first attempt to assess complex Hg isotope dynamics in the internal system of Arctic Phocidae, controlling the effects of age, diet, and distribution. Our results confirm the validity of Hg stable isotopes as tracers of environmental Hg sources even in top predators, but emphasize the importance of animal age and tissue selection for inter-study and inter-species comparisons. | 14. Life below water
Afficher plus [+] Moins [-]A seawater field study of crude and fuel oil depletion in Northern Norway at two different seasons – Chemistry and bacterial communities | A seawater field study of crude and fuel oil depletion in Northern Norway at two different seasons – Chemistry and bacterial communities
2024
Langeloh, Hendrik Hinrich | Hakvåg, Sigrid | Øverjordet, Ida Beathe | Bakke, Ingrid | Sørensen, Lisbet | Brakstad, Odd Gunnar
After marine oil spills, natural processes like photooxidation and biodegradation can remove the oil from the environment. However, these processes are strongly influenced by environmental conditions. To achieve a greater understanding of how seasonal variations in temperature, light exposure and the bacterial community affect oil depletion in the marine environment, we performed two field experiments during the spring and autumn. Field systems equipped with a thin oil film of Statfjord, Grane or ULSFO were deployed in northern Norway. Depletion of the total extractable matter was faster during the spring than during the autumn. Statfjord showed faster depletion of n-alkanes during spring, while depletion of polycyclic aromatic hydrocarbons varied between the seasons based on the degree of alkyl-substitutions. ULSFO displayed the overall slowest depletion. Biodegradation of the oils was associated with high abundances of unassigned bacteria during the spring but was governed by Alcanivorax, Cycloclasticus, Oleibacter and Oleispira during the autumn. | publishedVersion
Afficher plus [+] Moins [-]Lagrangian modelling of oil concentrations at sea: a sensitivity analysis to the grid resolution and number of Lagrangian elements
2024
Martínez Gómez, Andrés | Abascal Santillana, Ana Julia | García Gómez, Andrés | Aragón Caminero, Germán | Medina Santamaría, Raúl | Universidad de Cantabria
This paper presents a novel method to select the optimal combination of grid resolution and number of Lagrangian elements (LEs) required in numerical modelling of oil concentrations at sea. A sensitivity analysis in terms of grid resolution and the number of LEs, was carried out to understand the uncertainty that these userdependent parameters introduce in the numerical results. A dataset of 211,200 simulations performed under 400 metocean patterns, 6 initial volumes, 11 grid resolutions, and different numbers of LEs (100 to 500,000), was used to analyze the sensitivity of the model along different Thresholds of Concern. Results show the importance of a correct selection of the number of LEs and the grid resolution in Lagrangian modelling of surface oil concentrations. The method proposed will allow selecting the optimal combination of these parameters to find an optimal balance between the accuracy and the computational cost of the simulation. | This work was partly carried out in the framework of the project PID2020-117267RB-I00 (COIL) funded by MCIN/AEI/10.13039/501100011033// and the project PDC2021-120892-I00 (BLOWHAZARD) funded by MCIN/AEI/10.13039/501100011033 and by European Union Next GenerationEU/PRTR.
Afficher plus [+] Moins [-]Review on Methods for Assessing and Predicting Leaching of PFAS from Solid Matrices
2024
Navarro, Divina A. | Kabiri, Shervin S. | Bowles, Karl | Knight, Emma R | Braeunig, Jennifer | Srivastava, Prashant | Boxall, Naomi J. | Douglas, Grant | Mueller, Jochen | McLaughlin, Mike J. | Williams, Mike | Kookana, Rai S.
This article reviews methods for estimating leaching of PFAS from contaminated materials. Given the variety of methods, selecting those that best simulate assessment objectives is essential. Specific scenarios requiring PFAS leaching assessment, such as leaving materials in place, reuse, and disposal, are discussed. The knowledge gaps presented could be used to improve existing leaching methods for better predictions and understanding of PFAS leachability. | publishedVersion
Afficher plus [+] Moins [-]Floating microplastics in Svalbard fjords: High spatial variability requires methodological consistency in estuarine systems
2024
Pakhomova, Svetlana | Berezina, Anfisa | Zhdanov, Igor | Mekhova, Olga | Ilinskaya, Alisa | Golyakov, Alexey | Polivanova, Tatiana | Gebruk, Anna | Lusher, Amy Lorraine | Yakushev, Evgeniy
Microplastic pollution was studied in surface waters of Isfjorden, Svalbard in July 2021 as a part of an international regional harmonisation exercise. Surface microplastics (0.5–5 mm) were sampled with a neuston net in triplicate per study site in several branches of Isfjorden, covering populated and unpopulated fjords. High spatial variability of microplastic abundance (0–32,700 items/km2) was observed within a single fjord resulting from the hydrodynamic pattern formed through the interaction of surface currents, freshwater runoff, and wind conditions. Maximum microplastic abundance was not correlated with the distance from the local source and was instead defined by local small-scale hydrodynamics. Future recommendations for correct assessment of surface microplastics concentration in estuarine environments are presented. | publishedVersion
Afficher plus [+] Moins [-]