L'étude présentée ici concerne la répartition du 210Pb atmosphérique à l'échelle globale dans l'environnement. Ce travail débute par une étude expérimentale concernant les mesures de flux de dépôt atmosphérique de 210Pb dans les pluies, les sols et la neige. Une base de données a ensuite été construite en regroupant les mesures effectuées ces quatre dernières décennies. Celle-ci se focalise sur les concentrations de 210Pb dans l'air de surface et sur les flux de dépôt d'origine atmosphérique mesurés aux interfaces atmosphère-surface terrestre (collecteurs artificiels, sols et neige) et eau-sédiment. Cette base de données est ensuite exploitée. Les données de 210Pb atmosphérique sont analysées qualitativement en termes de transport (circulation atmosphérique) et de mécanismes de dépôt, et utilisées quantitativement pour la validation d'un modèle de circulation générale (GCM). En dernière partie, les données de flux de dépôt de 210Pb à l'interface eau-sédiment sont comparées statistiquement aux données de flux de dépôt atmosphérique. Cette comparaison est appliquée à l'étude des transferts entre l'atmosphère et les sédiments et permet ainsi de distinguer quatre différents types de réservoirs aquatiques.

<p>Uzorci zemlji&scaron;ta iz pov&scaron;inskog sloja dubine 0 - 10 cm<br />prikupljeni su sa 121 lokacije na gradskom području Novog<br />Sada. Ispitivano područje obuhvatilo je povr&scaron;inu (4 x 5)km²,<br />koja je podeljena na mrežna polja veličine (400 x 400) m^2&nbsp;i u&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />svakom polju uzet je po jedan uzorak. Za 121 uzorak<br />gradskog zemlji&scaron;ta Novog Sada ispitana su fizičko-hemijska<br />svojstva zemlji&scaron;ta, ukupni i pristupačni sadržaj metala (As,<br />Co, Cr, Cu, Mn, Ni, Pb, Zn) i njihova prostorna raspodela.<br />Konturne mape prostorne raspodele metala u zemlji&scaron;tu<br />dobijene su kori&scaron;ćenjem interpolacijske metode običnog<br />kriginga. Za pojedine uzorke izvr&scaron;eno je razdvajanje čestica<br />po veličinama frakcionisanjem u vodi pomoću sita različitih<br />veličina i identifikovani su minerali prisutni u frakciji prah +<br />glina. Aktivnosti radionuklida &bdquo;unsupported&rdquo;²¹⁰Pb i ¹³⁷Cs<br />određene su za jedan deo uzoraka zemlji&scaron;ta u Novom Sadu i<br />za uzorke zemlji&scaron;ta pored fabrike akumulatora u Somboru.<br />Ispitana je i vertikalna distribucija stabilnog i radioaktivnog<br />Pb u zemlji&scaron;tu.</p><p>Na 14 lokacija u Novom Sadu prikupljeno je 35 uzoraka<br />snega direktno sa asfaltnih puteva i sa zemljanih povr&scaron;ina u<br />okolini puteva i na pe&scaron;ačkim ostrvima. Raspodela čestica po<br />veličinama i ukupne koncentracije metala (Al, Ca, Cu, Fe, K,<br />Na, Mn, Ni, Pb, Zn) određene su analizom filtriranih uzoraka,<br />a za 4 uzorka ispitana je morfologija čestica i urađena<br />semikvantitativna analiza čestica u suvoj materiji.</p><p>Prilikom obrade rezultata merenja primenjene su metode<br />deskriptivne statistike i multivarijacione statističke analize u<br />cilju identifikacije izvora zagađenja i određivanja povezanosti<br />između samih metala i drugih parametara.</p> / <p>A total of 121 surface soil samples were collected&nbsp;across the central part of Novi Sad covering a surface&nbsp;area (4 km x 5 km). The physicochemical properties,&nbsp;pseudo total and available metal concentrations (As,&nbsp;Co, Cr, Cu,&nbsp; Mn, Ni, Pb, and Zn) were determined.&nbsp;Contour maps of spatial distribution of the investigated&nbsp;metals were obtained using ordinary&nbsp; kriging&nbsp;interpolation method. Separation of different particle&nbsp;<br />size fractions by wet sieving&nbsp; and identification of&nbsp;minerals in the clay and silt fraction for some soil&nbsp;samples were performed.&nbsp; Specific activities of&nbsp;radionuclides &ldquo;unsupported&rdquo; ²¹⁰Pb and ¹³⁷Cs were&nbsp;measured in forty soil samples collected in urban area&nbsp;of Novi Sad and industrial area of Sombor (near a&nbsp;battery manufacturer).&nbsp; Vertical distribution of stable and&nbsp;radioactive&nbsp; Pb for&nbsp; two samples from the industrial soil&nbsp;was examined.</p><p>Thirty five snow samples were collected at fourteen&nbsp;locations near crossroads in Novi Sad. The samples&nbsp;were taken directly from the road surface and from the&nbsp;ground surface in the vicinity of roads and on&nbsp;pedestrian islands. Particle size distribution and &nbsp;total&nbsp;concentration of the metals (Al, Ca, Cu, Fe, K, Na, Mn,&nbsp;Ni, Pb, Zn) were &nbsp;determined for filtered samples. Semi-quantitative analysis of the particles was &nbsp;conducted and&nbsp;morphology of the particles was examined for dry&nbsp;matter of four snow samples.&nbsp;</p><p>Methods of descriptive and multivariate statistics and&nbsp;geostatistics were carried out for &nbsp;the analysis and&nbsp;interpretation of the data.</p>

Using a comparative spatial and temporal analysis on sediment cores from 8 lakes in the Mackenzie River Delta uplands region, NT, Canada, this study assessed how persistent organic pollutant (POP) deposition to lake sediments was affected by: (1) the presence of retrogressive thaw slumps on lake shores; and (2) changes occurring with increased autochthonous primary productivity. POPs examined included polychlorinated biphenyls (PCBs), penta- and hexachlorobenzenes (CBzs), and dichlorodiphenyltrichloroethane and metabolites (DDTs). Surface sediments of slump-affected lakes contained higher total organic carbon (TOC)-normalized POP concentrations than nearby reference lakes unaffected by thaw slumps. Inorganic sedimentation rates were positively related to contaminant concentrations, suggesting that the influx of siliciclastic material reducing organic carbon in slump-affected lake water indirectly results in higher concentrations of POPs on sedimentary organic matter. This explanation was corroborated by an inverse relationship between sedimentary POP concentrations and TOC content of the lake water. Deposition proxies of autochthonous carbon were not significantly correlated to POP fluxes of surface sediments, and historical profile fluctuations did not coincide with variation in POP deposition. Thus this study does not support the contention that algal-derived organic carbon increases the delivery of organic pollutants to sediments (the algal-scavenging hypothesis), as previously proposed for mercury. Higher POP concentrations observed in surface sediments of slump-affected lakes are best explained by simple solvent switching processes of hydrophobic contaminants onto a lower pool of available organic carbon when compared to neighbouring lakes unaffected by thaw slump development.

Using a comparative spatial and temporal analysis on sediment cores from 8 lakes in the Mackenzie River Delta uplands region, NT, Canada, this study assessed how persistent organic pollutant (POP) deposition to lake sediments was affected by: (1) the presence of retrogressive thaw slumps on lake shores; and (2) changes occurring with increased autochthonous primary productivity. POPs examined included polychlorinated biphenyls (PCBs), penta- and hexachlorobenzenes (CBzs), and dichlorodiphenyltrichloroethane and metabolites (DDTs). Surface sediments of slump-affected lakes contained higher total organic carbon (TOC)-normalized POP concentrations than nearby reference lakes unaffected by thaw slumps. Inorganic sedimentation rates were positively related to contaminant concentrations, suggesting that the influx of siliciclastic material reducing organic carbon in slump-affected lake water indirectly results in higher concentrations of POPs on sedimentary organic matter. This explanation was corroborated by an inverse relationship between sedimentary POP concentrations and TOC content of the lake water. Deposition proxies of autochthonous carbon were not significantly correlated to POP fluxes of surface sediments, and historical profile fluctuations did not coincide with variation in POP deposition. Thus this study does not support the contention that algal-derived organic carbon increases the delivery of organic pollutants to sediments (the algal-scavenging hypothesis), as previously proposed for mercury. Higher POP concentrations observed in surface sediments of slump-affected lakes are best explained by simple solvent switching processes of hydrophobic contaminants onto a lower pool of available organic carbon when compared to neighbouring lakes unaffected by thaw slump development.