Histoire de la pollution en métaux lourds de l'atmosphère de l'hémisphère nord au cours des deux derniers siècles retracée dans les neiges du Groenland central : thèse soutenue sur un ensemble de travaux

Cette these presente l'evolution temporelle des concentrations en metaux lourds (pb, cd, zn et cu) mesurees dans les neiges de Summit (Groenland central) deposées entre 1773 et 1992. Les resultats obtenus mettent en evidence que les activites industrielles ont largement pollue la troposphere de l'hemisphere nord a l'echelle globale. Pour le plomb, nous confirmons et completons pour la premiere fois l'augmentation d'un facteur 200 depuis les niveaux naturels (il y a 8000 ans) observé pour les neiges du milieu des années 1960, mise en evidence par c. Patterson et ses collègues en 1969. L'augmentation observee pour les autres metaux (8 fois pour cd, 5 et 4 fois pour zn et cu) montre pour la première fois l'émergence de la source anthropique sur la période 1773-1970. Malgrè la décroissance très nette des concentrations en plomb (6.3 fois), en cadmium (2,3 fois) et en zinc (1.7 fois) observée sur la periode 1970-1992, les teneurs actuelles en métaux lourds des neiges du Groenland central sont encore supérieures aux concentrations observées pour les glaces de l'Holocène, ce qui prouve que les cycles atmosphériques biogéochimiques sont toujours largement dominés par les émissions d'origine humaine.pas de résum

Post industrial revolution changes in large scale atmospheric pollution of the northern hemisphere for heavy metals as documented in central Greenland snow and ice

International audiencePb, Zn, Cd and Cu have been measured using ultraclean procedures in various sections of a 70.3-m snow/ice core coveting the past 220 years (including the Industrial Revolution) drilled at Summit, central Greenland. These time series are the first reliable ones ever published for Zn, Cd, and Cu; for Pb they are the first verification of the pioneering data published more than two decades ago by C. Patterson and his coworkers [Murozumi et al., 1969]. For all four heavy metals, concentrations are found to have markedly increased up until the 1960s and 1970s before decreasing significantly during the following few decades. The timing and the amplitude of the observed changes differ significantly however from one metal to another. Comparison with concentration values obtained by analyzing ancient Holocene ice dated 7760 years B.P., that is, before humans started to impact on the atmosphere, show that no detectable increase occurred for Zn, Cd, and Cu before the Industrial Revolution. On the other hand, Pb concentrations were already one order of magnitude above natural values in late 18th century ice. Cumulative deposition of heavy metals to the whole Greenland ice cap since the Industrial Revolution ranges from 3200 t for Pb to 60 t for Cd

History of ancient copper smelting pollution during Roman and medieval times recorded in Greenland ice

Determination of copper concentrations in Greenland ice dated from seven millennia ago to the present showed values exceeding natural levels, beginning about 2500 years ago. This early large-scale pollution of the atmosphere of the Northern Hemisphere is attributed to emissions from the crude, highly polluting smelting technologies used for copper production during Roman and medieval times, especially in Europe and China. This study opens the way to a quantitative assessment of the history of early metal production, which was instrumental in the development of human cultures during ancient eras

Greenland Ice Evidence of Hemispheric Lead Pollution Two Millennia Ago by Greek and Roman Civilizations

Analysis of the Greenland ice core covering the period from 3000 to 500 years ago-the Greek, Roman, Medieval and Renaissance times-shows that lead is present at concentrations four times as great as natural values from about 2500 to 1700 years ago (500 B.C. to 300 A.D.). These results show that Greek and Roman lead and silver mining and smelting activities polluted the middle troposphere of the Northern Hemisphere on a hemispheric scale two millennia ago, long before the Industrial Revolution. Cumulative lead fallout to the Greenland Ice Sheet during these eight centuries was as high as 15 percent of that caused by the massive use of lead alkyl additives in gasoline since the 1930s. Pronounced lead pollution is also observed during Medieval and Renaissance times

Inductively coupled plasma mass spectrometry hyphenated to capillary gas chromatography as a detection system for the speciation analysis of organolead compounds in environmental water

The application of an inductively coupled plasma mass spectrometry detection system to the speciation of organolead compounds in environmental waters is described. Derivatization was carried out by propylation with a Grignard reagent after extraction of the organolead compounds into hexane as their diethyldithiocarbamate complexes. This was followed by separation and detection with capillary gas chromatography and inductively coupled plasma mass spectrometry. Detection limits ranging from 10 fg (0.05 ng l(-1)) (as Pb) for trimethyllead to 16 fg (0.08 ng l(-1)) (as Ph) for diethyllead were achieved. The accuracy of the method was confirmed by additional analysis of the water samples with capillary gas chromatography coupled to microwave-induced plasma atomic emission spectrometry and by the analysis of a reference material from the Standards, Measurements & Testing Programme of the European Union

Northern hemispheric organic lead emissions in fresh Greenland snow

International audienceIonic alkyllead species have been determined in fresh or slightly aged surface snow from Greenland relying on ultraclean sampling, high-resolution separation of individual species, and ultrasensitive determination procedures. The samples were collected from January to August 1989 on a precipitation event basis at Dye 3 (south Greenland) and in late spring and summer 1987 and 1989 at or near the Summit site (central Greenland). Evidence for long-range transport of organolead compounds into the very remote environment is given, and the nature and extent of the global pollution by organolead compounds are evaluated. Triethyl- and diethyllead species were found in all the samples, whereas methyllead species were absent in the late spring and summer samples. Monoalkyllead, mixed ionic organolead, and tetraalkyllead species were always found to be below 10-20 fg/g. The average total organolead concentrations form January to April was very high (476 fg/g, values between 100 and 800 fg/g, 0.3-2% of the total Pb), whereas the average summer concentration (May-August) was a factor of 5 lower (82.6 fg/g, values between 15 and 220 fg/g, less than 0.4% of the total lead). The variations in the concentrations measured are interpreted in terms of backwards air mass trajectories. Source regions influencing Dye 3 at different times are indicated. Organolead compounds in Greenland are established to be valuable indicators of the global character of the lead pollution originated specifically in the use of leaded gasoline. © 1994 American Chemical Society

Present century snow core record of organolead pollution in Greenland

International audienceIonic alkyllead species have been determined in precisely dated consecutive layers of a 25-m-deep snow core obtained by drilling at the Summit site, relying on ultraclean sampling, high-resolution separation of individual species, and ultrasensitive determination procedures. Ethylleads were the only species found in the concentration ratio varying from 5 to 400 fg/g. The concentrations found show an increasing trend since the early 1970s until the late 1980s that is slightly blurred by seasonal variations. The results are correlated with the data on the distribution of organolead species in gasoline, the consumption levels of leaded gasoline in Europe and the United States, and the concentrations and isotopic compositions of total lead in particular samples. Unambiguous evidence of the gasoline-related sources of lead in aged Greenland snow and ice during the past 70 years are provided. In contrast to Pb-(II), no dramatic drop in the northern hemispheric pollution by organic lead in the 1970s is observed. © 1994 American Chemical Society