239 research outputs found
From Grand dad’s to Grand daughter’s binge drinking – A recent evolution of heavy episodic alcoholic consumption in Ireland.
This article is aimed at understanding how female students perceive and explain the feminisation of binge drinking among their age group in Ireland. It focuses on the responsibility of older generations as well as female students’ gender and ethnic identity quests as possible explanatory factors for their increasing level of episodic heavy alcohol consumption. This empirical research was of a qualitative nature. 50 female students at the Institute of Technology Blanchardstown, Dublin 15, were interviewed individually in 2011 and 2012. The findings might be of significance in order to improve the effectiveness prevention strategies implemented in Ireland to reduce heavy episodic consumption among female students
Variabilités naturelle et anthropique des dépôts atmosphériques en éléments traces et en radionucléides dans les milieux distants de sources de pollution
Ce mémoire d'habilitation présente une synthèse de mes travaux depuis la fin de mon doctorat. Il rassemble une compilation de ma recherche sur les dépôts atmosphériques en éléments traces et en radionucléides dans les milieux distants de sources de pollution. Il illustre l'intérêt d'une approche couplée entre des traceurs isotopiques variés et des enregistrements spatio-temporels diversifiés pour comprendre la dynamique et l'origine des éléments trace dans l'environnement, en particulier en milieux montagnards et/ou aux interfaces atmosphère-sol-eau (la zone critique). Ce document présente également mon curriculum-vitae détaillé y compris les encadrements de thèses et de masters, ma liste de publications ainsi que les reproductions d'articles scientifiques les plus significatifs
Fate of natural and anthropogenic particles in peat bogs
Investigating atmospheric deposition over a scale of millennial period is crucial because humans are emitting more and more synthetic and natural compounds (i.e.: pollutants and/or dust) to the environment through the atmosphere. It is therefore necessary to determine the background deposition rate of these compounds, to assess their natural variations (ie.: temporal and/or spatial) and to understand the effects of the increased atmospheric depositions induced by humans on the environment. The primary aim of this work was to improve the understanding of the processes affecting the fate of anthropogenic and natural particles in peat bogs, to see which geochemical processes can affect the suitability and accuracy of peat bogs as archives of atmospheric deposition, and also the effects of these inputs on the bog ecosystem. To test whether peat bogs are accurate archives of Pb atmospheric deposition, Pb distribution was investigated in Kohlhütte Moor (KM), a bog in Southern Germany. Pb is a toxic element extensively dispersed by human activities (Chap.2.1). The atmospheric Pb record assessed using a peat core was compared with other archives, including a snow pack and previously studied Swiss peat cores (Chap.2.2). To this end, new improved methods both methodically (Chap.1.1) and analytically (Chap.1.2 and Chap.1.3) were developed. Also particular attention was given to age dating using 210Pb and 14C and the estimation of the Pb accumulation rate (AR) based on these ages. The most recent Pb AR in KM (2.5 mg m-2 y-1) is similar to that obtained from the snow pack on the bog surface (1 to 4 mg m-2 y-1). The isotopic composition of Pb was measured in both the modern and ancient peat samples as well as in the snow samples, and clearly shows that recent inputs are dominated by anthropogenic Pb. The chronology and isotopic composition of atmospheric Pb accumulation recorded by the peat from the Black Forest is similar to the chronologies reported earlier using peat cores from various Swiss peat bogs and point to a common Pb source to the region for the past 200 years. Taken together, the results show that peat cores from ombrotrophic bogs can yield accurate records of atmospheric Pb deposition, provided that the cores are carefully collected, handled, prepared, and analysed using appropriate methods. In addition, the rates of atmospheric Pb accumulation at least for the last 6000 years were quantified using peat cores from KM and Lindow Bog (LDW), England. In KM, the most recent Pb accumulation rate (2.5 mg m-2 y-1) is 50 to 200 times greater than the “natural” average background rate of atmospheric Pb accumulation (~20 µg m-2 y-1) calculated using “pre-anthropogenic” samples from the same site. The core from LDW (Chap.2.3) shows the potential of carefully studying Pb distribution in a peat profile for regional paleo-ecology and archaeology. Using the Pb/Ti ratio to calculate the rates of anthropogenic, atmospheric Pb deposition, the core reveals Pb contamination first appearing in peat samples dating from ca. 900 B.C. which clearly pre-date Roman mining activities. The timing of the ancient and medieval Pb pollution is also directly related to socio-economical events. 208Pb/206Pb and 206Pb/207Pb data indicate that English ores were the predominant sources for atmospheric deposition in England during the pre-Roman, Roman, and medieval periods. To test whether peat bogs are suitable archives of atmospheric deposition of minerals and after a review of the different possible dissolution mechanisms influencing inorganic particles (Chap.3.1), mineral distributions in the upper part of KM were investigated (Chap.3.2). Similar minerals to the local granite were identified using X-Ray-Diffraction: most of the minerals are therefore of local origin. The distribution of quartz and feldspars is unaffected by the low pH and the abundance of organic acids, possibly due to the early formation of a siliceous layer and/or coating by humic acids. Therefore the preservation of quartz and feldspars in ombrotrophic peat might make bogs useful archives of the changing rates of atmospheric dust since the Last Glacial. In addition, other minerals, calcite and apatite, were identified but only in the topmost samples of the bog. They probably dissolve comparatively quickly and thereby influence the chemistry of the surface of the bog releasing nutrients and therefore influencing the botanical composition of the bog and the rates of plant growth
Aerosol deposition and origin in French mountains estimated with soil inventories of 210Pb and artificial radionuclides
Radionuclide inventories were measured in soils from different French mountainous areas: Chaîne des Puys (Massif Central), Eastern Corsica, Jura, Montagne Noire, Savoie, Vosges and Rhine Valley. 210Pb soil inventories were used to estimate long-term (>75 yr) deposition of submicron aerosols. Whereas 210Pb total deposition is explained partly by wet deposition, as demonstrated by increase of 210Pb inventory with annual rainfall; a part of 210Pb in the soils of higher altitude is caused by orographic depositions. Using measurements of radionuclides coming from nuclear aerial weapon tests (137Cs and Pu isotopes), we were able to estimate the origin of aerosols deposited in high-altitude sites and to confirm the importance of occult deposition and feeder–seeder mechanism. Using a simple mass balance model, we estimate that occult deposition and feeder–seeder mechanisms account to more than 50% of total deposition of 210Pb and associated submicron aerosols in French altitude sites
Peat as an archive of atmospheric pollution and environmental change : A case study of lead in Europe
Inorganic geochemistry in peat deposits provides unique and valuable indications of human activities and consequent environmental changes
Inorganic Chemistry in the Mountain Critical Zone : Are the mountain water towers of contemporary society under threat by trace contaminants ?
Potentially harmful trace elements (PHTEs) do not accumulate homogeneously over mountainous area. Generally, highland areas receive more wet deposition, aerosols, and ions than surrounding lowlands ones, mainly due to orographic enhancement. Within mountainous areas, however, the accumulation of PHTEs is much more complex. Direct cloud deposition of contaminants could act as an important pathway of deposition either from a regional low-altitude, cloud level, orographic clouds, or haze whose frequency of occurrence is much higher than surrounding lowlands areas. The accumulation legacy of PHTEs from local human activities should also be considered when investigating PHTE distribution in mountainous areas. Combined with other phenomena, the PHTE accumulation patterns could be highly variable depending on local topography, dominant winds, and vegetation cover, as well as present and past local practices. Despite their remoteness, mountain ecosystems are highly sensitive to PHTEs loadings
Deposition of artificial radionuclides from atmospheric Nuclear Weapon Tests estimated by soil inventories in French areas low-impacted by Chernobyl
Soil inventories of anthropogenic radionuclides were investigated in altitudinal transects in 2 French regions, Savoie and Montagne Noire. Rain was negligible in these 2 areas the days after the Chernobyl accident. Thus anthropogenic radionuclides are coming hypothetically only from Global Fallout following Atmospheric Nuclear Weapon Tests. This is confirmed by the isotopic signatures (238Pu/239þ240Pu; 137Cs/239þ240Pu; and 241Am/239þ240Pu) close to Global Fallout value. In Savoie, a peat core age-dated by 210Pbex confirmed that the main part of deposition of anthropogenic radionuclides occurred during the late sixties and the early seventies. In agreement with previous studies, the anthropogenic radionuclide inventories are well correlated with the annual precipitations. However, this is the first time that a study investigates such a large panel of annual precipitation and therefore of anthropogenic radionuclide deposition. It seems that at high-altitude sites, deposition of artificial radionuclides was higher possibly due to orographic precipitations
Atmospheric Deposition History of Trace Metals and Metalloids for the Last 200 Years Recorded by Three Peat Cores in Great Hinggan Mountain, Northeast China
A large number of studies on trace metals and metalloids (TMs) accumulations in peatlands have been reported in Europe and North America. Comparatively little information is available on peat chronological records of atmospheric TMs flux in China. Therefore, the objective of our study was to determine the concentrations and accumulation rates (ARs) of TMs in Motianling peatland from Great Hinggan Mountain, northeast China, and to assess these in relation to establish a historical profile of atmospheric metal emissions from anthropogenic sources. To meet these aims we analyzed 14 TMs (As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sr, Sb, Tl, and Zn) and Pb isotopes (206Pb, 207Pb, 208Pb) using ICP-AES and ICP-MS, respectively, in three peat sections dated by 210Pb and 137Cs techniques (approximately spanning the last 200 years). There is a general agreement in the elemental concentration profiles which suggests that all investigated elements were conserved in the Motianling bog. Three principal components were discriminated by principal componentanalysis (PCA) based on Eigen-values >1 and explaining 85% of the total variance of element concentrations: the first component representing Ba, Co, Cr, Mo, Ni, Sr and Tl reflected the lithogenic source; the second component covering As, Cu and Sb, and Cd is associated with an anthropogenic source from ore mining and processing; the third component (Pb isotope, Pb and Zn) is affected by anthropogenic Pb pollution from industrial manufacturing and fossil-fuel combustion. The pre-industrial background of typical pollution elements was estimated as the average concentrations of TMs in peat samples prior to 1830 AD and with a 207Pb/206Pb ratio close to 1.9. ARs and enrichment factors (EFs) of TMs suggested enhanced metal concentrations near the surface of the peatland (in peat layers dated from the 1980s) linked to an increasing trend since the 2000s. This pollution pattern is also fingerprinted by the Pb isotopic composition, even after the ban of leaded gasoline use in China. Emissions from coal and leaded gasoline combustions in northern China are regarded as one of the major sources of anthropogenic Pb input in this region; meanwhile, the long-distance transportation of Pb-bearing aerosols from Mongolia should be also taken into consideration. The reconstructed history of TMs’ pollution over the past ca. 200 years is in agreement with the industrial development in China and clearly illustrates the influence of human activities on local rural environments. This study shows the utility of taking multi-cores to show the heterogeneity in peat accumulation and applying PCA, EF and Pb isotope methods in multi-proxies analyses for establishing a high resolution geochemical metal record from peatland
Origin and fluxes of atmospheric REE entering an ombrotrophic peat bog in Black Forest (SW Germany): Evidence from snow, lichens and mosses
The fate of the Rare Earth Elements (REE) were investigated in different types of archives of atmospheric deposition in the Black Forest, Southern Germany: (1) a 70 cm snow pack collected on the domed part of a raised bog and representing 2 months of snow accumulation, (2) a snow sample collected close to the road about 500 m from the peat bog, (3) two species of lichens and (4) a peat profile representing 400 years of peat accumulation as well as a “preanthropogenic” sample and the living moss layer from the top of the core. REE concentrations in peat are significantly correlated to Ti which is a lithogenic conservative element suggesting that REE are immobile in peat bog environments. Snow, lichens and peat samples show similar PAAS (Post Archean Australian Shale) normalized REE distributions suggesting that the complete atmospheric REE signal is preserved in the peat profile. However, the annual flux of REE accumulated by the peat is ca. 10 times greater than that of the bulk winter flux of REE. This difference probably indicates that the REE concentrations in the snowpack are not representative of the average REE flux over the whole year. Despite the pronounced geological differences between this site (granite host-rock) and a previously studied peat bog in Switzerland (limestone host-rock) similar REE distribution patterns and accumulation rates were found at both sites. Given that both sites confirm an Upper Continental Crust signature, the data suggests both sites are influenced by regional and not local, soil-derived lithogenic aerosols
Recent atmospheric Pb deposition at a rural site in southern Germany assessed using a peat core and snowpack, and comparison with other archives
In a peat bog from Black Forest, Southern Germany, the rate of atmospheric Pb accumulation was quantified using a peat core dated by 210Pb and 14C. The most recent Pb accumulation rate (2.5 mg m−2 y−1) is similar to that obtained from a snowpack on the bog surface, which was sampled during the winter 2002 (1 to 4 mg m−2 y−1). The Pb accumulation rates recorded by the peat during the last 25 yr are also in agreement with published values of direct atmospheric fluxes in Black Forest. These values are 50 to 200 times greater than the “natural” average background rate of atmospheric Pb accumulation (20 μg m−2 y−1) obtained using peat samples from the same bog dating from 3300 to 1300 cal. yr B.C. The isotopic composition of Pb was measured in both the modern and ancient peat samples as well as in the snow samples, and clearly shows that recent inputs are dominated by anthropogenic Pb. The chronology and isotopic composition of atmospheric Pb accumulation recorded by the peat from the Black Forest is similar to the chronologies reported earlier using peat cores from various peat bogs as well as herbarium samples of Sphagnum and point to a common Pb source to the region for the past 150 years. In contrast, Pb contamination occurring before 1850 in southwestern Germany, differs from the record published for Switzerland mainly due to the mining activity in Black Forest. Taken together, the results show that peat cores from ombrotrophic bogs can yield accurate records of atmospheric Pb deposition, provided that the cores are carefully collected, handled, prepared, and analysed using appropriate methods
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