Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

At this moment there is a gap in information regarding the affect roots might have on 210Pb distribution in peat cores and in turn the obtained chronologies by 210Pb dating. Therefore, four peat cores were collected from the snow manipulation study site within the mire complex Storflaket (68°20048″N, 18°58016″E). Two cores from snow fence plots, which has experienced root growth due to permafrost thaw, and 2 cores from control plots. 210Pb distribution and the provided 210Pb chronologies were then compared with root content within and between the cores. In two of the cores (C5 and SF2) did subsurface peaks in the 210Pb activity profile follow the distribution profile of the dwarf shrub roots. The same pattern was not seen with Eriophorum roots. This indicates that presence of dwarf root with their shallow and horizontally growth can affect the 210Pb profile by horizontal translocation of 210Pb. The chronologies obtained by the CF:CS and CRS dating models could not be validated for the C5 core which suggest that dwarf shrub roots also can affect the 21oPb dating.

L’objectif de ce travail était de tester l’utilisation des radioisotopes naturels à courte période (234Th, 7Be et 210Pb) comme traceurs des transferts des particules dans le bassin versant de la Garonne-Dordogne-Gironde. Dans un premier temps, la faisabilité de la méthode basée sur le 234Th a été testée dans les rivières. Les résultats ont montré qu’une valeur de 5 mBq l-1 correspondant au seuil en 238UD est nécessaire pour l’application du 234Th en rivière. Dans un deuxième temps, le suivi sur deux années (2006-2007) des radioéléments naturels, 234Th, 7Be et 210Pb, et artificiels, 137Cs et 131I, dans le Lot, la Garonne et l’estuaire de la Gironde, a permis de distinguer les différentes étapes du transport des particules en relation avec l’hydrologie. L’atout de l’utilisation de ces traceurs est d’accéder à de premières estimations du temps de résidence des sédiments et du pourcentage des fractions anciennes et récentes. Dans le Lot et la Garonne, il existe une rétention des particules (2-89 jours) pendant l’étiage et les débits moyens, et de fortes remises en suspension des sédiments anciens à débits élevés. La moyenne du pourcentage des sédiments récents dans les rivières est d’environ 25 %, ce qui montre que les matériaux en suspension (MES) dans les rivières sont dominés par des sédiments anciens. Dans l’estuaire de la Gironde, le temps de résidence varie en fonction de l’hydrologie des rivières : pendant les périodes de forts débits, le temps de transit des particules de la Réole jusqu’à l’océan est seulement de quelque mois (~150 jours) ; alors que pendant les périodes d’étiage, l’âge des sédiments augmente dans la zone de turbidité maximum atteignant jusqu’à 400 jours. / The main objective of this study was to develop short-lived radioisotopes (234Th, 7Be and 210Pb) as tracers of particle transport in the Garonne-Dordogne-Gironde watershed. Firstly, the possibility to use 234Th/238U pair to study particle residence time in the Gironde fluvial-estuarine system was tested. The results show that dissolved 238U should be greater than 5 mBq l-1 to permit this application in fluvial systems. Secondly, the two years monitoring of natural radioisotopes, 234Th, 7Be and 210Pb, and artificial radioisotopes, 137Cs and 131I, in the Garonne and Lot rivers and in the Gironde Estuary, had allowed to observe the dynamic of particle transport, linked to the river flow. Based on this database, preliminary particle residence times and percentages of the new and old sediments were estimated. In the Lot and Garonne rivers, the particle retention ranges between 2-89 days during low and mean river discharges. The percentage of the new sediments is average 25 %, which indicates that the old resuspended sediments are dominated the suspended particulate matters (SPM). In the Gironde estuary, the particle residence time is mainly controlled by river discharge. The particle residence time during low river discharge is about 400 days. When the river discharge is increasing, the freshwaters are predominant in the estuary, the maximum turbidity zone (TMZ) is dispersed and the old sediments transported toward the ocean. During this period the particle residence time is only few months.

Le lessivage du lutum (0-2 µm) est un de processus majeurs de la pédogenèse, qui a néanmoins été peu quantifié et modélisé. Ce processus ainsi que la bioturbation ont été quantifiés ici en couplant des différents systèmes isotopiques (137Cs, 210Pb (xs), 10Be atmosphérique, 206/207Pb, δ13C, 14C) à une modélisation numérique par une équation de diffusion-convection à paramètres variables avec la profondeur. Cette méthode originale a été appliquée sur des anthroposéquences de Luvisols développées sur du loess et différantes de par leur utilisation (culture, prairie ou forêt) et leurs pratiques agricoles (travail du sol, apport du fumier). Nos résultats montrent que 91 ± 9 % du 137Cs et 80 ± 9 % du 10Be sont associés au lutum et ainsi peuvent effectivement tracer des transferts verticaux de matière solide dans les sols à pH > 5 et à teneur en carbone organique faible. Le partage du plomb entre les différentes phases solides est plus complexe. En considérant deux compartiments pour les isotopes (macropores ou la matrice de sol), nous avons conçu un modèle multi-isotopique permettant de quantifier la contribution des transferts de matière solide à la distribution verticale de la fraction 0-2 µm actuelle. Le lessivage est responsable de 9 à 66 % de l'accumulation de lutum dans l'horizon Bt. Le coefficient de diffusion permet de quantifier le taux de mélange par la bioturbation. La modélisation multi-isotopique est une méthode de prédilection pour les études modernes de la pédogenèse et des processus de la zone critique. / Clay translocation is one of the major soil forming processes, howeverit is poorly quantified and modeled. We propose to quantify it togetherwith bioturbation by combining different isotopic systems (137Cs , 210Pb (xs),meteoric 10Be, 206/207Pb, δ13C, 14C) with numerical modeling based on a nonlineardiffusion-convection equation with depth dependent parameters. Thisnovel method has been applied on Luvisol anthroposequences developed onloess, differing by their land use (cropping versus grassland or forest) andtheir agricultural practices (reduced tillage, no tillage and manure input).Our results show that as much as 91 ± 9 % and 80 ± 9 % of 137Cs and10Be, respectively, are associated to the clay size fraction (0-2 µm) and canthus effectively trace vertical solid matter transfers in soils with pH > 5 andlow organic carbon. Lead partitioning between different solid phases is morecomplex. Considering two spatial distributions of isotopes (macropores or soilmatrix), we built up a multi-isotopic modelling approach that simulates theexperimental data with the common set of transfer parameters and allowedus to quantify the relative contributions of vertical solid matter transfers topresent-day 0-2 µm vertical distributions. Clay translocation is responsiblefor 9 to 66 % of the clay accumulations in the Bt-horizon. The diffusion coefficientalso quantifies the rate of soil mixing by bioturbation. Modeling of thekinetics of solid matter transfer at multiple spatio-temporal scales should becomea method of predilection in modern pedogenic and critical zone studies.

Although Lake Victoria is threatened by pollution there is a lack of knowledge about pharmaceuticals contaminants drained into the lake from large cities bordering the lake. Hence, the purpose of this project was to develop, validate and apply a method for analysis of pharmaceutical compounds accumulating in the Lake Victoria sediments. A simple quantitative method for 11 pharmaceuticals combining accelerated solvent extraction, solid phase extraction, trimethylsilylation derivatization, and gas chromatography mass spectrometry was developed, partly validated, and applied to 18 surface sediments and a sediment core dated using the 210Pb method. The results showed the presence of the pharmaceuticals estriol, gemfibrozil, metoprolol, ketoprofen, naproxen, 17α-ethinylestradiol and estrone concentrated around the regions Napoleon Gulf and Thurston Bay with accumulation rates decreasing towards the top of the sediment core. Nonetheless, a randomness in the distribution of these compounds behooves a systematic assessment investigating not only the provenance of these compounds but also further investigations to errors meaning that this study should be treated as a preliminary investigation.

[pt] A cidade de Atafona situada à foz do Rio Paraíba do Sul (RPS) vem sofrendo erosão em sua linha de costa por muitas décadas. Este estudo consiste em uma avaliação das taxas de sedimentação no estuário do Paraíba do Sul e suas correlações com a forte erosão que ocorre em Atafona, Rio de Janeiro. O trabalho foi baseado em quatro transetes ao longo do Estuário do rio Paraíba do Sul contendo 14 pontos de coleta. Cerca de 540 amostras de sedimentos foram obtidas em Janeiro de 2010 e Fevereiro de 2011. As taxas de sedimentação foram determinadas a partir do método da datação com 210Pb e os inventários de 210Pb foram determinados para todos os pontos de coleta. Foram aplicados dois modelos para a determinação das taxas de sedimentação: o modelo da Concentração Inicial Constante (modelo CIC) e o modelo da Razão de Suprimento Constante (modelo CRS). Os resultados da datação 210Pb foram validados com base na variação da concentração elementar ao longo de dois testemunhos. A determinação de elementos foi realizada utilizando a técnica de Espectrometria de Massa com Plasma Indutivamente Acoplado (ICP-MS). A análise multivariada de dados foi aplicada através da análise de fatores principais (AFP) e análise hierárquica de cluster (AHC) a fim de obter informações que traduzam quantitativamente a composição dos sedimentos descrevendo a região. Os inventários de 210Pb determinados nos pontos de coleta, localizados ao sul do rio Paraíba do Sul (RPS), foram maiores do que os determinados nos pontos de coleta localizados ao centro e ao norte da saída do rio. O valor médio do inventário obtido nos pontos de coleta ao sul da foz do RPS foi de 1,0 Bq cm-2, muito superior ao valor médio obtido nos pontos situados ao norte da foz do rio, com valor de 0,16 Bq cm-2, indicando que os sedimentos são transportados na direção sul da foz do RPS, ao longo da costa com as correntes de deriva existentes nesta direção. A taxa de acumulação estimada para as camadas mais profundas foi de 0,06 g cm-2 ano-1. Essa taxa representa um valor base para a taxa de acumulação de sedimentos para o período anterior a 1950. As taxas de acumulação obtidas para o período mais recente variaram de 0,2 g cm-2 ano-1 nos pontos situados ao norte e ao centro a 0,6 g cm-2 ano-1 nos pontos situados ao sul da foz do RPS. Observou-se que as concentrações de Cr, Cu, Cd e Zn aumentaram significativamente a partir dos anos oitenta que, coincide com a época do acidente ocorrido com a Cia. de Paraibuna Metais em 1982. Uma das consequências nas mudanças no uso da terra e do represamento de rios é a mudança na natureza dos sedimentos que chegam e se depositam no delta do RPS. A normalização da concentração dos metais pelo alumínio pode ajudar a traçar tais mudanças, principalmente com elementos de origem distinta, como Ca e Mg. Através da curva obtida entre razão a Mg/Al e as idades das camadas sedimentares pode-se observar uma forte mudança no período entre 1962 e 1988. Foram identificados quatro fatores através da AFP traduzindo quatro fases do sedimento: duas representando a matriz, uma representando os carbonatos e a outra representando os sulfetos. / [en] The city of Atafona, situated at Paraíba do Sul Estuary, has been suffering erosion in its coastline for decades. This study is an evaluation of sedimentation rates in the Paraíba do Sul estuary and its correlation with the strong erosion that occurs in Atafona city, Rio de Janeiro, Brazil. We performed four transects along Paraíba do Sul Estuary with 14 sampling points. About 540 sediment samples were collected in January 2010 and February 2011. Sedimentation rates were determined by 210Pb dating method and inventories of 210Pb were determined for all sampling points. Two models were applied for the sedimentation rates determination: the Constant Initial Concentration model (CIC-model) and the Constant Rate of Supply model (CRS-model). The 210Pb dating results were validated based on the elemental concentration variation throughout two of the sediment cores. The elements determination was performed using the mass spectrometry with inductively coupled plasma technique (ICP-MS). The multivariate analysis were applied trough the principal factor analysis (PFA) and hierarchical cluster analysis (HAC) in order to obtain factors that may traduce quantitatively the sample composition describing the region. At sampling points located at south of the Paraiba do Sul River (PSR) mouth, 210Pb inventories were higher than those at the northern and central sampling locations. The inventory average obtained at south was 1.0 Bq cm-2, much higher than those located at north of the river mouth, with a mean value 0.16 Bq cm-2, indicating that the sediments are transported southward by the alongshore current. The accumulation rate estimated for the deeper layers was 0.06 g cm-2 yr-1, which represents a reference value of sediment accumulation rate for the period prior to 1950. Accumulation rates obtained for the most recent period ranged from 0.2 g cm-2 yr-1 in the points situated at north and center to 0.6 g cm-2 yr-1 in points located at south of RPS mouth. It was observed that Cr, Cu, Cd and Zn concentrations increased significantly from the eighties that matches with the Cia Paraibuna Metals accident occurred in 1982. A consequence of changes in land use and the damming of the river is a change in the nature of the particulates reaching the PSR delta. The normalization of elemental concentrations to aluminum could help trace these changes, particularly for elements with a distinct origin, such as Ca and Mg. The Mg/Al versus ages plot showed a strong change between 1962 and 1988. There were four factors identified that traduce four sediment phases, two of them were related to the matrix, other was related to the carbonate phase and the other representing sulfides phase.

<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>

Die Anpassung von Küstenniederungen, Seemarschen und Inseln an klimatische Veränderungen und einen steigenden Meeresspiegel ist eine der großen Herausforderungen des 21. Jahrhunderts. Im Gegensatz zu eingedeichten Küstenmarschen und Inseln besitzen tidebeeinflusste Seemarschen ein natürliches Anpassungspotential an sich verändernde hydrologische Rahmenbedingungen. Überflutungsabhängige Sedimenteinträge führen zu einem Anwachsen der Marschoberfläche und kompensieren somit einen Anstieg des Meeresspiegels. Die 10 verbliebenen nordfriesischen Halligen (Schleswig-Holstein, Deutschland) (Kapitel 1) sind bewohnte Inselmarschen, welche aufgrund ihrer anthropogenen Überprägung von naturbelassenen Seemarschen unterschieden werden müssen. Diese umfasst z.B. den Bau von flachen Sommerdeichen und Sielanlagen. Inwiefern sich diese Veränderungen auf die Sedimentdynamik der Marschen auswirken, ist bislang unzureichend belegt, was eine fundierte Diskussion bezüglich zukünftiger Entwicklungsperspektiven der Halligmarschen verhindert. Die vorliegende Arbeit ist dazu angelegt, diese Wissenslücke zu schließen. Sie untersucht das vertikale Marschwachstum exemplarisch auf den Halligen Hooge, Langeneß und Nordstrandischmoor und beurteilt deren Anpassungsvermögen an einen steigenden Meeresspiegel. Darüber hinaus werden zukünftige Entwicklungsperspektiven diskutiert. Um Faktoren und Prozesse, welche maßgeblich die Sedimentdynamik der Halligen beeinflussen, messbar zu machen, musstengeeignete Methoden entwickelt und angewendet werden. Zur Berechnung jährlicher Überflutungshäufigkeiten wurden Pegelschwellenwerte für Überflutungsereignisse auf Basis von digitalen Geländemodellen (DGMs) und d-GPS (differential global positioning system) Messungen errechnet und auf die verfügbaren, regionalen Pegeldaten angewendet (Kapitel 2). Sedimentfallen, bestehend aus LDPE (low density polyethylene) Flaschen (1 Liter) und Kunstrasenmatten (20 x 30 cm), bilden die Grundlage einer dreijährigen (November 2010 – März 2013) Feld- und Laborstudie zur zeitlichen und räumlichen Erfassung der sturmflutabhängigen Sedimentdeposition (Kapitel 3). Durch die Verwendung regionaler bodenphysikalischer Parameter (Lagerungsdichte und Gehalt an organischer Bodensubstanz) können Depositionsraten in eine vertikale Wachstumskomponente transformiert werden. Dazu werden Ergebnisse einer Rammkernsondierung genutzt, welche 12 Sedimentkerne mit einer Länge von maximal 100 cm umfasst. Die Sedimentbohrkerne sind weiterhin die Grundlage für eine 137Cs- und 210Pb-Datierung. Die Kombination beider Datensätze (Kapitel 4) ermöglicht einen schlüssigen Vergleich der Marschentwicklung seit dem Jahr 1915 mit regionalen Pegeldaten und Projektionen des zukünftigen Meeresspiegelanstiegs. Die Analyse der verfügbaren Pegeldaten (Kapitel 2) zeigt eine hohe Variabilität der jährlichen Überflutungshäufigkeiten. Das zehnjährige Mittel eintretender Ereignisse beträgt 2 Überflutungen auf Hooge, 9 – 10 Überflutungen auf Langeneß und 15 Überflutungen auf Nordstrandischmoor. Aufgrund der künstlichen Überhöhung der Marschkante durch Sommerdeiche mit + 1.54 m ü. mittlerem Tidehochwasser (MThw) auf Hooge und + 0.98 m ü. MThw auf Langeneß werden die betreffenden Halligen lediglich bei selten eintretenden Sturmflutereignissen überflutet. Die Höhe des wasser- und sedimentundurchlässigen Steinpflasters auf Nordstrandischmoor beträgt lediglich + 0.7 m ü. MThw. Die methodischen Untersuchungen bezüglich der Nutzung von Sedimentfallen (Kapitel 3) zeigen, dass beide Typen von Sedimentfallen vergleichbare Ergebnisse liefern. Oberhalb einer Depositionsrate von ~ 2.0 kg/m2 sinkt das Rückhaltevermögen der Kunstrasenmatte im Vergleich zur LDPE Flasche deutlich ab. Die parallele Nutzung beider Fallentypen, insbesondere wenn die Depositionsraten den Schwellenwert (~ 2.0 kg/m2) nicht überschreiten, erlaubt: (1) Die Überprüfung, ob beide Datensätze konsistent sind. (2) Die Identifizierung von Ausreißern. (3) Eine Abschätzung, ob Sediment auf oder in der Sedimentfalle nach der Überflutung remobilisiert wird. Um die Sedimentdeposition in eine vertikale Wachstumsrate zu übersetzen, muss die mittlere Bodendichte als auch der Gehalt an organischer Bodensubstanz des Marschbodens berücksichtigt werden. Die Bohrkernuntersuchungen zeigen, dass diese bodenphysikalischen Parameter auf den unterschiedlichen Halligen stark variieren. Marschen, die häufig überflutet werden lagern weniger organisches Material im Oberboden ein als selten überflutete Marschen. Niedrige Gehalte an leichten organischen Materialien geringer Dichte resultieren wiederum in einer höheren Lagerungsdichte des Marschbodens (Hooge 0.64 g/cm3, Langeneß 0.67 g/cm3, Nordstrandischmoor 0.83 g/cm3). Autochthones organisches Material (welches primär von der Halligvegetation stammt) trägt mit einem Anteil von 9.0 ± 1.4 % (Hooge) bis 21.4 ± 6.6 % (Nordstrandischmoor) zum Marschwachstum bei. Die Ergebnisse der Sedimentfallenuntersuchungen als auch der Datierungen zeigen deutlich ein Ungleichgewicht zwischen Marschwachstum und Meeresspiegelanstieg seit Beginn des 20. Jahrhunderts. Die langjährigen Wachstumsraten, basierend auf der 210Pb-Datierung, liegen mit 1.0 ± 0.3 mm/a auf Hooge, 1.2 ± 0.3 mm/a auf Langeneß und 2.6 ± 0.9 mm/a auf Nordstrandischmoor deutlich unterhalb des MThw-Anstiegs von 5.0 ± 0.3 mm/a (1951 – 2011, Wyk auf Föhr). Projektionen des Meeresspiegelanstiegs bis zum Jahr 2100 (Berechnet durch das fwu, Siegen) weisen darauf hin, dass extreme Wasserstände (höchste, jährliche Tidehochwasserstände, HThw, 6.6 ± 3.8 mm/a) deutlich schneller ansteigen werden als das MThw oder der mittlere Meeresspiegel (2.6 ± 0.4 mm/a). Aufgrund dieser Beobachtungen ist von einem zukünftigen Anstieg des Gefährdungspotentials für die Halligen auszugehen, wenn es nicht gelingt, ein sedimentologisches Gelichgewicht zwischen Meeresspiegel und Marschwachstum herzu stellen. Der Anstieg der Wellenhöhe und Periode, aufgrund von steigender Wassertiefe und einer geringeren Wellentransmissionsrate an den Sommerdeichen, resultiert in einer steigenden hydrodynamischen Belastung der Warften und der Marschoberfläche. Das sedimentäre Ungleichgewicht, besonders auf Hooge und Langeneß, kann eindeutig auf das hydrologische Management der Halligen zurückgeführt werden. Aus sedimentologischer Sicht sind die beiden Hauptkritikpunkte (1) die geringe Anzahl an Überflutungen aufgrund der Deichanlagen und (2) der eingeschränkte Transport suspendierter Feststoffe über die Binnenpriele. Letzteres resultiert aus der Blockade der Binnenpriele durch Sielanlagen und führt zu einer Abnahme der Sedimentdeposition mit zunehmender Entfernung zur Uferlinie. Um dem Ungleichgewicht zwischen Marschwachstum und Meeresspiegelanstieg entgegenzuwirken, ist es dringend erforderlich, neue Managementstrategien für die Halligen zu entwickeln (Kapitel 6), welche sedimentologische/geomorphologische Aspekte sowie die speziellen Bedürfnisse der Halligbevölkerung gleichermaßen berücksichtigen. Letztere beinhalten die Minimierung ökonomischer Schäden wie etwa Einschränkungen der landwirtschaftlichen Nutzung oder des Tourismus. Mögliche Szenarien können ein Abflachen der bestehenden Deiche oder deren Rückbau und Erneuerung durch wasser- und sedimentdurchlässige Rauhstreifen (z.B. Elastocoast®, BASF) beinhalten. Weiterhin erscheint die Reaktivierung der blockierten Binnenpriele eine plausible Maßnahme zu sein. Erste Freilandexperimente auf Hallig Langeneß (Kapitel 5) belegen einen erhöhten Sedimenttransport in die Binnenmarsch aufgrund geöffneter Sielanlagen in Verbindung mit Windstau (Thw-Ereignisse über Springtideniveau). Ob die generelle Umsetzung derartiger Maßnahmen möglich ist, ist in erster Linie davon abhängig, ob die Halligbevölkerung derartigen Veränderungen ihrer Umwelt aufgeschlossen gegenübersteht und diese lokalpolitisch getragen werden. Auf jeden Fall ist ein Umdenken dahingehend erforderlich, die halligtypischen Überflutungen (Land-Unter) nicht ausschließlich als Bedrohung zu verstehen. Sie sind ein natürliches Phänomen, welches notwendig ist, um das Gleichgewicht zwischen Meeresspiegelanstieg und Sedimentdeposition aufrechtzuerhalten.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2018-02-08T13:16:32Z No. of bitstreams: 1 Dissertação Monteiro.pdf: 846441 bytes, checksum: b2f2bba3715f02d6517b44747e771a73 (MD5) / Made available in DSpace on 2018-02-08T13:16:32Z (GMT). No. of bitstreams: 1 Dissertação Monteiro.pdf: 846441 bytes, checksum: b2f2bba3715f02d6517b44747e771a73 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / Este trabalho tem como objetivo estudar o aporte dos metais-traço Pb, Zn, Ni, Cu, V, Ba, Co, Cd em sedimentos do estuário do Rio Iguaçu e da região da Área de Proteção Ambiental de Guapimirim, comparando o grau de acumulação destes metais nestes diferentes ambientes estudados. Para isso, foram coletados dois testemunhos de sedimentos, um na margem deposicional do Rio Iguaçu (RED3) e o outro entre as fozes dos rios Guapi e Guarai (MAC), na Baía de Guanabara. O testemunho RED3 apresentou sedimentos com granulometria predominantemente composta por argila e silte, com máximo de areia de 3%, enquanto o testemunho MAC também apresentou granulometria fina, porém este apresentou até 20% de areia em algumas camadas sedimentares. Ambos os testemunhos mostraram mudanças nas taxas de sedimentação a partir da segunda metade do século XX, refletindo o início do acelerado processo de urbanização da área metropolitana do Rio de Janeiro. As concentrações de carbono orgânico, metais-traço, Fe e Mn determinados nos sedimentos do testemunho RED3 oscilaram ao longo de todo testemunho, sugerindo uma elevada dinâmica do Rio Iguaçu. Foi verificado um incremento na concentração de todos os metais-traço, Fe e Mn por volta de 1987, sugerindo uma redistribuição diagenética dos metais. Já o perfil de concentração dos metais-traço determinados no testemunho MAC mostraram dois períodos de valores de background. O primeiro é da base até 75 cm de profundidade (equivalente ao ano de 1872), mostrando um ambiente deposicional com predominância de argila, matéria orgânica alóctone e baixos valores de concentração de metais-traço. Acima desta profundidade ocorreu um progressivo incremento nas concentrações dos metais, com alguns metais chegando a dobrar suas concentrações, e a partir daí mantendo-se relativamente constantes até a superfície (com exceção do Zn e Pb). Estes incrementos provavelmente foram influenciados pelas novas condições ambientais da bacia de drenagem do final do século XIX, possivelmente devido ao processo de desmatamento, ocasionando assim uma maior erosão e intemperismo do solo. Os resultados dos inventários, fluxos e fatores de enriquecimento dos metais-traço tanto se mostraram mais elevados na região do Rio Iguaçu do que na área de proteção ambiental, quanto nos demais importantes estuários mundial. / The aim of the present work is to study the input of trace metals of environmental interest, such as Pb, Zn, Ni, Cu, V, Ba, Co e Cd, in sediments from the Iguaçu River and the Guapimirim Environmental Protection Area estuaries, comparing the degrees of metal accumulation between these environments. Two sediment cores were collected in 2007, one from the mudflat inside the Iguaçu River (RED3) and the other near the Guapi and Guarai river mouths (MAC). The sediment core RED3 presented sediments predominately composed for silte and clay, with a maximum sand content of 3%. The sediment core MAC also presented fine granulometric size, however it showed up to 20% of sand in some sedimentary layers. Both sediment cores showed a change in sedimentation rates from the second half of the twentieth century, which might be reflecting the beginning of an accelerated industrialization process and development of the Rio de Janeiro Metropolitan Area. The sediment core RED3 presented a large concentration variation of organic carbon, trace metals, Fe and Mn. This might be a reflection of the high Iguaçu River hydrodynamic. All the trace metals, Fe and Mn presented a concentration increase in the second half of the 1980’s, suggesting a vertical redistribution due the process diagenetic. The trace metal concentration found in the MAC core showed two background levels. The first level consists of concentrations measured from the core bottom up to 75 cm, which was equivalent to records up to 1872. Moreover, the sediments from those environmental conditions predominantly presented clay, aloctone organic matter and low concentrations of trace metals. From the mentioned depth onwards, there were concentration increases. Once increased, the concentration remained constant until the top of the core (except Zn and Pb). These increases were probably influenced by the new environmental conditions catchment in the end of XIX century, possibly due to a deforestation process, which occasioned major erosion and weathering. Inventory, flux and trace metal enrichment factors showed highest in the Iguaçu River than in the Guapimirim Environmental Protection Area other estuaries and the others important estuaries of the world.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2018-02-20T15:41:21Z No. of bitstreams: 1 Dissertação Tatiana.pdf: 566030 bytes, checksum: 62e1cb6cc4c14e38f8541ff8477ed25c (MD5) / Made available in DSpace on 2018-02-20T15:41:21Z (GMT). No. of bitstreams: 1 Dissertação Tatiana.pdf: 566030 bytes, checksum: 62e1cb6cc4c14e38f8541ff8477ed25c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / Com o desenvolvimento industriais de regiões costeiras, tornou-se necessário o estudo de metais em áreas não impactadas, como a Baía de Ilha Grande, devido a carência de estudos nestes sistemas por serem comparados as áreas impactadas. No presente estudo dois testemunhos foram coletados; um a enseada de Abrão em Ilha Grande e o outro na porção Leste na Baía de Sepetiba, Rio de Janeiro. / With the industrial development of coastal regions, it became necessary to study metals in non-impacted areas, such as Ilha Grande Bay, due to the lack of studies in these systems because the impacted areas were compared. In the present study, two samples were collected; one the Abrão cove in Ilha Grande and the other in the eastern portion in Sepetiba Bay, Rio de Janeiro.