International audience | he aim of this study is to bring to light the influence on firewood emissions and performance of several parameters like the moisture content of the fuel, the presence of bark, the caliber of the fuel but also the ignition mode. Many results emerge from this study. First of all, all these parameters significantly impact the emissions of the firewood at the nominal thermal heat output, especially the particles emissions. The presence of bark modifies the particles composition in total carbon. Moreover, the presence of bark induces the emissions of a new family of particles: the nanocrystal. A high moisture of the fuel led to a lower temperature in the combustion chamber. Then, the emissions of unburned gases, like the Volatile Organic Compounds, will considerably increase. The particles emissions and the composition of those particles were also significantly impacted by the moisture of the fuel. Two ignition modes were also studied. It appears that the top-down ignition against the traditional ignition allowed a significant decrease of all the emissions. Nevertheless, the elemental carbon emissions were more important with a top-down ignition. | L’objectif de cette étude est de mettre en évidence l’influence sur les émissions et les performances d’un appareil de différents paramètres, comme l’humidité du bois, la présence d’écorce ou non, le calibre utilisé ainsi que le mode d’allumage. De nombreux résultats ressortent de cette étude. Tout d’abord, tous ces paramètres influent de manière considérable sur les émissions des appareils, notamment les émissions de particules, et ce, même à régime nominal. La présence d’écorce modifie la composition en carbone total des particules totales et implique l’émission d’un nouveau type de particule : les nano-cristaux. Une humidité élevée induit des niveaux de températures plus faibles. Ainsi, les émissions d’imbrûlés gazeux tels que les Composés Organiques Volatils vont augmenter de manière importante. Les émissions de particules, en quantité et en composition chimique, sont aussi significativement impactées par l’humidité du combustible. Deux modes d’allumage ont aussi été étudiés. Il s’avère qu’un allumage inversé permet de réduire de manière significative la globalité des émissions par rapport à un allumage classique. En effet, seules les émissions de Carbone Elémentaire sont plus importantes avec un allumage inversé.

L’objectif de cette étude est de mettre en évidence l’influence sur les émissions et les performances d’un appareil de différents paramètres, comme l’humidité du bois, la présence d’écorce ou non, le calibre utilisé ainsi que le mode d’allumage. De nombreux résultats ressortent de cette étude. Tout d’abord, tous ces paramètres influent de manière considérable sur les émissions des appareils, notamment les émissions de particules, et ce, même à régime nominal. La présence d’écorce modifie la composition en carbone total des particules totales et implique l’émission d’un nouveau type de particule : les nano-cristaux. Une humidité élevée induit des niveaux de températures plus faibles. Ainsi, les émissions d’imbrûlés gazeux tels que les Composés Organiques Volatils vont augmenter de manière importante. Les émissions de particules, en quantité et en composition chimique, sont aussi significativement impactées par l’humidité du combustible. Deux modes d’allumage ont aussi été étudiés. Il s’avère qu’un allumage inversé permet de réduire de manière significative la globalité des émissions par rapport à un allumage classique. En effet, seules les émissions de Carbone Elémentaire sont plus importantes avec un allumage inversé. | he aim of this study is to bring to light the influence on firewood emissions and performance of several parameters like the moisture content of the fuel, the presence of bark, the caliber of the fuel but also the ignition mode. Many results emerge from this study. First of all, all these parameters significantly impact the emissions of the firewood at the nominal thermal heat output, especially the particles emissions. The presence of bark modifies the particles composition in total carbon. Moreover, the presence of bark induces the emissions of a new family of particles: the nanocrystal. A high moisture of the fuel led to a lower temperature in the combustion chamber. Then, the emissions of unburned gases, like the Volatile Organic Compounds, will considerably increase. The particles emissions and the composition of those particles were also significantly impacted by the moisture of the fuel. Two ignition modes were also studied. It appears that the top-down ignition against the traditional ignition allowed a significant decrease of all the emissions. Nevertheless, the elemental carbon emissions were more important with a top-down ignition.

no sp Assessment of Nitrogen Fluxes to Air and Water from Site Scale to Continental Scale | absent

absent

International audience | This study evaluates the efficiency of two small constructed wetlands installed in the regulatory grass strips between a drained plot and a river. The observed nitrate removal efficiencies were independent of the season or type of constructed wetland and ranged from 5.4 to 10.9% of the inlet amounts. The pesticide mass budgets ranged from −618.5 to 100%, depending on the molecule. The negative efficiencies were attributed to runoff and remobilization. In contrast, the highest efficiencies were associated with pesticides with high Koc and low DT50 (half-life) values, suggesting sorption and degradation. However, the effectiveness of these wetlands is limited for pesticides with low Koc or high DT50 values; thus, the use of these molecules must be reduced. Increasing the number of these small, inexpensive and low-maintenance wetlands in the agricultural landscape would reduce the level of water pollution whilst preserving the extent of cultivated land, but their long-term effectiveness should be evaluated.

This study evaluates the efficiency of two small constructed wetlands installed in the regulatory grass strips between a drained plot and a river. The observed nitrate removal efficiencies were independent of the season or type of constructed wetland and ranged from 5.4 to 10.9% of the inlet amounts. The pesticide mass budgets ranged from −618.5 to 100%, depending on the molecule. The negative efficiencies were attributed to runoff and remobilization. In contrast, the highest efficiencies were associated with pesticides with high Koc and low DT50 (half-life) values, suggesting sorption and degradation. However, the effectiveness of these wetlands is limited for pesticides with low Koc or high DT50 values; thus, the use of these molecules must be reduced. Increasing the number of these small, inexpensive and low-maintenance wetlands in the agricultural landscape would reduce the level of water pollution whilst preserving the extent of cultivated land, but their long-term effectiveness should be evaluated.

International audience | Particle-size classes (7 fractions from 0.8 to 2000 µm) were collected in the deep chlorophyll maximum along a Mediterranean transect including the northern coastal zone (bays of Toulon and Marseilles, France), the offshore zone (near the North Balearic Thermal Front), and the southern coastal zone (Gulf of Gabès, Tunisia). Concentrations of biotic metals and metalloids (As, Cd, Cr, Cu, Fe, Mn, Ni, Sb, V, Zn) bound to living or dead organisms and faecal pellets were assessed by phosphorus normalisation. Biotic metals and metalloids concentrations (except Cr, Mn, and V) were higher in the offshore zone than in the coastal zones. In addition, biotic Sb and V concentrations appeared to be affected by atmospheric deposition, and biotic Cr concentrations appeared to be affected by local anthropogenic inputs. Essential elements (Cd, Cu, Fe, Mn, Ni, V, Zn) were very likely controlled both by the metabolic activity of certain organisms (nanoeukaryotes, copepods) and trophic structure. In the northern coastal zone, biomagnification of essential elements was controlled by copepods activities. In the offshore zone, metals and metalloids were not biomagnified probably due to homeostasis regulatory processes in organisms. In the southern coastal zone, biomagnification of As, Cu, Cr, Sb could probably induce specific effects within the planktonic network.

Particle-size classes (7 fractions from 0.8 to 2000 μm) were collected in the deep chlorophyll maximum along a Mediterranean transect including the northern coastal zone (bays of Toulon and Marseilles, France), the offshore zone (near the North Balearic Thermal Front), and the southern coastal zone (Gulf of Gabès, Tunisia). Concentrations of biotic metals and metalloids (As, Cd, Cr, Cu, Fe, Mn, Ni, Sb, V, Zn) bound to living or dead organisms and faecal pellets were assessed by phosphorus normalisation. Biotic metals and metalloids concentrations (except Cr, Mn, and V) were higher in the offshore zone than in the coastal zones. In addition, biotic Sb and V concentrations appeared to be affected by atmospheric deposition, and biotic Cr concentrations appeared to be affected by local anthropogenic inputs. Essential elements (Cd, Cu, Fe, Mn, Ni, V, Zn) were very likely controlled both by the metabolic activity of certain organisms (nanoeukaryotes, copepods) and trophic structure. In the northern coastal zone, biomagnification of essential elements was controlled by copepods activities. In the offshore zone, metals and metalloids were not biomagnified probably due to homeostasis regulatory processes in organisms. In the southern coastal zone, biomagnification of As, Cu, Cr, Sb could probably induce specific effects within the planktonic network.

More than 70 years of industrial production of per- and polyfluoroalkyl substances (PFAS) have resulted in their ubiquitous presence in the environment on a global scale, although differences in sources, transport and fate lead to variability of occurrence in the environment. Gull eggs are excellent bioindicators of environmental pollution, especially for persistent organic pollutants such as PFAS, known to bioaccumulate in organisms and to be deposited in bird eggs by maternal transfer. Using yellow-legged gull (Larus michahellis) eggs, we investigated the occurrence of more than 30 PFAS, including the most common chemicals (i.e., legacy PFAS) as well as their alternatives (i.e., emerging PFAS) in the Bay of Marseille, the second largest city in France. Compared to eggs from other colonies along the Mediterranean coast, those from Marseille had PFAS concentrations ranging from slightly higher to up to four times lower, suggesting that this area cannot be specifically identified as a hotspot for these compounds. We also found several emerging PFAS including 8:2 and 10:2 FTS, 7:3 FTCA or PFECHS in all collected eggs. Although the scarcity in toxicity thresholds for seabirds, especially during embryogenesis, does not enable any precise statement about the risks faced by this population, this study contributes to the effort in documenting legacy PFAS contamination on Mediterranean coasts while providing valuable novel inputs on PFAS of emerging concern. Identifying exposure in free-ranging species also participate to determine the main target for toxicity testing in wildlife. | publishedVersion

International audience | More than 70 years of industrial production of per-and polyfluoroalkyl substances (PFAS) have resulted in their ubiquitous presence in the environment on a global scale, although differences in sources, transport and fate lead to variability of occurrence in the environment. Gull eggs are excellent bioindicators of environmental pollution, especially for persistent organic pollutants such as PFAS, known to bioaccumulate in organisms and to be deposited in bird eggs by maternal transfer. Using yellow-legged gull (Larus michahellis) eggs, we investigated the occurrence of more than 30 PFAS, including the most common chemicals (i.e., legacy PFAS) as well as their alternatives (i.e., emerging PFAS) in the Bay of Marseille, the second largest city in France. Compared to eggs from other colonies along the Mediterranean coast, those from Marseille had PFAS concentrations ranging from slightly higher to up to four times lower, suggesting that this area cannot be specifically identified as a hotspot for these compounds. We also found several emerging PFAS including 8:2 and 10:2 FTS, 7:3 FTCA or PFECHS in all collected eggs. Although the scarcity in toxicity thresholds for seabirds, especially during embryogenesis, does not enable any precise statement about the risks faced by this population, this study contributes to the effort in documenting legacy PFAS contamination on Mediterranean coasts while providing valuable novel inputs on PFAS of emerging concern. Identifying exposure in free-ranging species also participate to determine the main target for toxicity testing in wildlife.