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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Classical over-the-barrier model for ionization of poly-cyclic aromatic hydrocarbons in keV-collisions with atomic ions

Forsberg, Björn January 2011 (has links)
We are developing a novel classical over-the barrier model for electron transfer from an in nitely thin conducting disc to a point charge projectile to model multiple electron capture in e.g. keV collisions of atomic ions with poly-cyclic aromatic hydrocarbons (PAHs). In its nal form, the present model will incorporate the polarization of the PAH molecules due to the active electron and the point charge projectile at a general angle of incidence. This will drastically improve the description of the potential barrier in comparisons with simpler versions of the model where the nite size and polarizability of the target molecule is neglected or treated in an averaged fashion. In this work we arrive at expressions for the electrostatic potential energy barrier experienced by the active electron in the two spatial orientations where the point charge projectile is located along the normal symmetry axis and in the tangent plane of the disc. Applied to coronene (C24H12) such barriers compare better with high level density functional theory (DFT) calculations than with the results from the simpler versions of the classical over-the-barrier models for atomic and spherical cluster targets. These results thus strongly supports the conducting disc approximation of PAHs. Finally we discuss the nal steps in the model development and possible extensions of the model to include less symmetric elliptical discs or spherical caps.
72

Nitro- e oxi-HPA no material particulado atmosférico: algumas contribuições para uma abordagem integrada / Nitro- and oxy-PAH in the atmospheric particulate matter: some contributions for an integrated approach

Alexandre Franco 29 September 2006 (has links)
Os derivados nitrados e oxigenados de hidrocarbonetos policíclicos aromáticos, nitro-HPA e oxi-HPA, podem ser encontrados no material particulado atmosférico e são provenientes da queima de combustíveis fósseis e biomassa, ou de reações dos HPA com gases atmosféricos. Determinados nitro-HPA e oxi-HPA apresentam mutagenicidade mais elevada do que a dos seus HPA precursores. O presente trabalho teve como objetivo avaliar os níveis de nitro-HPA e oxi-HPA nos extratos orgânicos do material particulado atmosférico das cidades de São Paulo, Araraquara, Paulínia e Piracicaba, durante períodos com e sem a queima da palha da cana-de-açúcar, verificar a possível existência de transporte de poluentes entre as regiões estudadas e determinar a mutagenicidade do material particulado. O material particulado atmosférico foi coletado em amostrador de grande volume com filtro de fibra de quartzo e extraído em Soxhlet. Os extratos foram submetidos à separação por HPLC, obtendo as frações de HPA, nitro-HPA e oxi-HPA, as quais foram analisadas por GC-MS. Tanto as frações como os extratos brutos foram submetidos a determinações gravimétricas e testes biológicos. Os nitro-compostos específicos, 1-nitropireno (1-NPir), 3-nitrofluoranteno (3-NFlt) e 6-nitrocriseno (6-NCri), para os quais há disponibilidade de padrões, foram analisados sendo que o 6-NCri não foi detectado em nenhuma amostra. Os níveis dos nitro-HPA encontrados (concentração máxima = 0,86 ngm-3) foram similares aos níveis reportados na literatura para diferentes cidades do mundo e o 3-NFlt apresentou níveis mais altos do que o 1-NPir em todas as amostras. Dentre os sítios estudados, São Paulo apresentou, em geral, níveis mais altos do que Araraquara, Piracicaba e Paulínia, apesar das concentrações altas de material particulado encontradas nesses três sítios. Em todos os sítios estudados houve um aumento nos níveis dos nitro-HPA no inverno, e não foi possível verificar se as emissões provenientes da queima da palha da cana-de-açúcar contribuem para os níveis desses poluentes. Na cidade de São Paulo, sítio mais estudado, foi observada uma variação sazonal evidenciada pelo aumento dos nitro-HPA no inverno de 2002. Níveis similares de nitro-HPA foram observados nos invernos de 2001 a 2004, exceto em 2003, onde os níveis foram mais altos devido provavelmente ao período longo de estiagem e às condições meteorológicas favoráveis à estagnação dos poluentes. Relacionando-se os níveis dos nitro-HPA com as trajetórias das massas de ar verificou-se um possível transporte de poluentes de uma região para outra em um único caso, de um total de 15. Dentre os oxi-HPA identificados (5H-fenantro(4,5-bcd)pirano-5-ona, 1-ácido fenantrenocarboxílico, 4H-ciclopenta(def)criseno-4-ona, 9,10-antracenodiona e benzantrona) a 9,10-antracenodiona e a benzantrona são comprovadamente mutagênicos. A benzantrona foi a mais freqüentemente encontrada nas amostras. Os níveis mais altos de oxi-HPA foram encontrados nas amostras de Araraquara e Piracicaba. Por final, pode-se concluir também, que as mutagenicidades das frações nitro- e oxi-HPA são as principais responsáveis pela mutagenicidade do extrato bruto, uma vez que a mutagenicidade das frações HPA praticamente não contribuiu para a mutagenicidade total. / Nitrated and oxygenated derivatives of polycyclic aromatic hydrocarbons, nitro-PAH and oxi-PAH, can be found in the atmospheric particulate matter from the combustion of fossil fuel and biomass or as result of PAH reactions with atmospheric gases. Some nitro-PAH and oxi-PAH compounds present higher mutagenicity than their parent PAH. The objective of this research was to evaluate the nitro- and oxi-PAH levels in organic extracts of atmospheric particulate matter collected at the cities of Sâo Paulo, Araraquara, Piracicaba and Paulinia, over periods with and without sugar cane burning, to analyze the possible transport of pollutants at these regions and to determine the mutagenicity of the particulate matter . The atmospheric particulate matter was collected by high volume sampler over quartz fiber filter and extracted with soxhlet. Extracts were submited to HPLC to obtain PAH, nitro-PAH and oxi-PAH fractions, which were analyzed by the GC-MS. Both fractions and extracts were subjected to gravimetric determinations and biological tests. Specific compounds, 1-nitropyrene (1-NPir), 3-nitrofluoranthene (3-NFlt) and 6-nitrocrisene (6-NCri) were analyzed and only 6-NCri was not detected in any of the samples. The determined levels of nitro-PAH (maximum concentration = 0,86 ngm-3) were similar to that reported in the literature for other cities of the world. In all samples, the 3-NFlt level was higher than that of 1-NPir. Among the studied areas, São Paulo presented, in general, higher levels than Araraquara, Piracicaba and Paulinia, despite the high concentration of particulate matter found at these areas. All the studied sites presented higher levels of nitro-PAH during the winter, and it was not possible to verify if the emissions of sugar cane burning contribute to the levels of these pollutants. An increase of the nitro-PAH during the winter of 2002 was observed in São Paulo, the more deeply studied site, showing a seasonal variation. Similar levels of nitro-PAH were observed in the winter of 2001, 2002 and 2004. In 2003, the levels were even higher probably due to the long period without rain and favorable meteorological conditions to the stagnation of pollutants. Relating the nitro-PAH levels with the air masses trajectories, it was observed that the pollutants were transported from a region to another in only one out of the 15 studied cases. Among the oxi-PAH identified (5H-phenanthro(4,5-bcd)pyran-5-one, 1-phenanthene carboxylic acid, 4H-ciclopenta(def)crisene-4-one, 9,10-anthracenedione and benzanthrone), the 9,10-anthracenedione and benzanthrone are mutagenic and were found in the most of the samples. Finally, the mutagenicity of the nitro-PAH and oxi-PAH fractions accounted for the mutagenicity of the organic extract, due to the fact that the mutagenicity of the PAH fractions was very low and its contribution to the total mutagenicity was negligible.
73

Um estudo sobre a caracterização de hidrocarbonetos policíclicos aromáticos e seus derivados, e hidrocarbonetos alifáticos saturados em material particulado atmosférico proveniente de sítios urbanos, suburbanos e forestais / Study on polycyclic aromatic hydrocarbons and their derivatives, and saturated aliphatic hydrocarbons charactization determined on atmospheric particulate matter collected in urban, suburban and forest areas

Pérola de Castro Vasconcellos 03 May 1996 (has links)
Entre os componentes orgânicos do material particulado atmosférico, os hidrocarbonetos policíclicos aromáticos tem importância pois além de responder positivamente a testes de mutagenicidade como os que utilizam a Salmonella typhimurium, fornecem informações sôbre a origem e a reatividade atmosférica. Em particular os isômeros do nitropireno e nitrofluoranteno são indicadores da poluição veicular (1-nitropireno é emitido diretamente por motores a diesel) ou relacionam-se a reatividade fotoquímica (2-nitrofluoranteno e 2-nitropireno são formados na fase gasosa pela reação dos HPAs precursores com NO2 e radicais OH e NO3). Este estudo teve o objetivo de identificar e quantificar os nitro-HPAs visando a avaliação da contribuição antropogênica e fotoquímica nos estudos dos processos responsáveis pela presença destes nitroarenos na atmosfera em sítios com diferentes características, comparando resultados obtidos nos centros urbanos (emissões diretas) e na floresta Amazônica (possível emissão durante a queima da biomassa). Paralelamente foi avaliada a ocorrência dos HPAs e dos hidrocarbonetos alifáticos saturados. Estes forneceram informações sôbre as principais fontes de emissão dos particulados nos vários sítios, a contribuição relativa das emissões naturais e antropogênicas e o tempo de residência das partículas. Na primeira fase do estudo foi desenvolvida uma metodologia para a separação dos nitro-HPAs, dos hidrocarbonetos alifáticos, HPAs e HPAs oxigenados que são particularmente abundantes no material particulado emitido pelos veículos e durante as queimadas. Esta metodologia foi testada e aperfeiçoada na Itália sôbre amostras coletadas em 3 sítios diferentes por amostradores de grande volume. Após a extração em Soxhlet, foi desenvolvido um método de extração líquida mais simples e rápida que as recentemente publicadas metodologias de separação, baseadas em colunas de alumina básica. A boa separação das classes de compostos mostrou que a metodologia desenvolvida foi adequada para determinação posterior dos HPAs, nitro-HPAs e oxi-HPAs em amostras de composição complexa como aquelas de origem natural, antropogênica e fotoquímica, típicas da Amazônia e São Paulo, que foram posteriormente analisadas. / A detailed knowledge of the organic components of the atmospheric suspended particulate matter is extremely useful for assessing the photochemical reactivity of the atmosphere, long-range transport of polluted air masses and the relative contribution of natural and anthropogenic sources to the total amount of organic matter that can be introduced into man\' s body. Among the organic species is very important the knowledge of the levels reached by nitrated polycyclic aromatic hydrocarbons (nitro-PAH) in general, and particularly nitrofluoranthene (NF a) and nitropyrene (NPy) isomers since these compounds not only provides information on the extent to which anthropogenic sources can contribute to suspended particulate matter but it is also useful for evaluating the photochemical processes occurring in the atmosphere. The possibility to use nitrofluoranthene and nitropyrene as indicators of biogenic emission and photochemical smog pollution associated with the observation that one of them (l-nitropyrene) is directly emitted by vehicular sources whereas the others (2-NFa and 2-NPy) are formed by gas-phase reactions of their parent PAH with OH and N03 radicals in the presence of N02. Another important reason for monitoring nitro-PAH is that they positively respond to mutagenicity tests performed with Salmonella typhimurium Strain TA 98 carried out without activation. This work had the aim of identify and quantify the nitro-PAH to evaluate the anthropogenic and photochemical contribution and study the main processes risponsible for the presence of these nitroarenes in the atmosphere in sites of differents characteristics, comparing the results of urban sites (direct emissions) to the forest sites. It is also important to know the particulate matter composition with respect to n-alkanes and PAH associated with the particulate matter because they provide indication on the main sources contributing to airbome particles, the reI ative contribution of natural vs. man-made emission and the aging of the particles. In the first part of this work a methodology to separate the nitro-PAH from the n-alkanes, PAH and oxy-PAH which are particularly abundant in the particulate matter emitted by the vehicles and during the biomass burning was developed. This new methodology has been tested and improved in Italy on samples from three different sites collected on Hi-vol filters which were submited to Soxhlet extraction and then purified by a new liquid-liquid extraction method which is simpler and faster than the recently published basic alumina based purification procedure. The results indicate the new methodology was suitable to determine the PAH, nitro-PAH and oxy-PAH in samples of complex composition as those from Amazon Basin and São Paulo City which were analysed later.
74

Optimierung der Fluoreszenzgraduierung von Polyelektrolyt-Multischichten auf kolloidalen Trägern für die Durchflusszytometrie

Rosche, Christopher 24 September 2012 (has links) (PDF)
Die Arbeit untersucht den Einfluss des pH - Wertes auf die Fluoreszenzintensität von Multischichtsystemen während des Beschichtungsvorgangs von Siliziumdioxidpartikeln mit kovalent an Polyallylaminhydrochlorid (PAH) gebundenem Rhodamin - B - Isothiocyanat. Durch eine konsequente Pufferung mit 2 -(N - Morpholino)ethansulfonsäure während der Beschichtung kann eine Verbesserung der Homogenität der Schichtbildung und eine Erhöhung der Fluoreszenzintensität erreicht werden. Außerdem liegt eine lineare Steigerung der Fluoreszenzintensität proportional zur Anzahl der fluoreszenten Schichten vor. Weiterhin sollen kolloidale Partikel unter konstanter Pufferung zusätzlich zu Rhodamin – B – Isothiocyanat mit an PAH – gebundenem Fluoresceinisothiocyanat beschichtet werden. Dieses Farbstoffpaar weist bei Annäherung eine Fluoreszenzsteigerung durch einen Fluoreszenzresonanzenergietransfer aus. Durch Variation von Schichtanzahl und Abstand wurden verschiedene Partikelpopulationen hergestellt, die sich in Ihrer Fluoreszenzintensität analog zu einem Bead Array Assay im Durchflusszytometer klar differenzieren lassen und dabei auch eine gleichmäßige Steigerung der Fluoreszenzintensität analog zur Anzahl der fluoreszenten Schichten aufweisen.
75

Stabilisering av tjärförorenat sediment i området Kolkajen-Ropsten / Stabilization of tar contaminated sediments in the area of Kolkajen-Ropsten

Sterud, Erik January 2017 (has links)
Sedimenten i området Kolkajen-Ropsten, Stockholm, innehåller höga halter av tjäroljor till följd avtidigare produktion i gasverket på området. Stockholms stad planerar att utföra byggnation i detnuvarande vattenområdet, vilket ökar risken för spridning av föroreningar. För att skydda arbetandeunder planerad byggnation och framtida boende måste föroreningssituationen åtgärdas. Tjäroljornainnehåller höga halter av polyaromatiska kolväten (PAH) och det är föroreningen av PAH-16 som styråtgärdsbehovet för området. En metod som använts med god framgång i flera projekt i Norden ochandra delar av världen är stabilisering och solidifiering, s/s, av sediment. Metoden går ut på att blandain utvalda bindemedel i sedimenten som då härdar. Därigenom minskar föroreningens mobilitet och degeotekniska egenskaperna förbättras. Om kravet på skjuvhållfasthet (>140 KPa), låg permeabilitet (10-8-10-9 m/s) samt minskad utlakning uppfylls kan de stabiliserade massorna utgöra grunden för planeradbyggnation.För att utvärdera möjligheterna av denna åtgärdsmetod analyserades en sats av prover från området föratt tillhandahålla information om platsspecifika parametrar. Analysen visade att sedimenten hade högvattenkvot och organiskt innehåll, dominerades av fina fraktioner samt en föroreningsgrad av PAH-16på 13000 mg/kg TS. Utifrån dessa parametrar och med stöd från en litteraturstudie valdes fyra receptpå bindemedel ut, med olika mängd bindemedel. De bindemedel som använts är: Bascement frånSkövde som är ett portland-flygaskecement, Monofill som består av 20 % cement och 80 % granuleratmasugnsslagg samt aktivt kol. De olika recepten blandades med sediment från området och lämnadesatt härda under 28 dygn. Efter härdningen utvärderades de stabiliserade massorna med avseende påminskad utlakning av PAH jämfört med obehandlat sediment, skjuvhållfasthet och permeabilitet.Analyser av de fyra blandningarna visade att kravet på skjuvhållfasthet och permeabilitet uppfylldesför samtliga tillsatser av bindemedel och överlag innebar större mängder tillsatt bindemedel högreskjuvhållfasthet och lägre permeabilitet. Resultaten från laktester indikerade att en större tillsats avaktivt kol minskade utlakningen av PAH.Tillsatsen av bindemedel som bedöms vara bäst lämpad för stabilisering av sedimenten från områdetvar en total mängd av cement och Monofill på 250 kg/m3 (30 % cement och 70 % Monofill) samt entillsats av aktivt kol på 5 % av TS.Inblandning i sedimenten enligt receptet ovan resulterade i en skjuvhållfasthet på 413 KPa samt enönskat låg permeabilitet. Utlakningen av PAH-16 reducerades med ~45 % jämfört med obehandlatsediment. / The sediments in the area Kolkajen-Ropsten, Stockholm, have shown high levels of tar oils due to thegasworks in the area. The city of Stockholm is planning construction in the area which increases therisk of contaminants spreading to the surrounding area. In order to protect workers during the plannedconstruction and future inhabitants, remediation has to be carried out. The tar oils have highconcentrations of polyaromatic hydrocarbons (PAH) and it is pollution of PAH-16 that dictates theneed for remediation.A remediation method that has been used in similar projects, with good results, is stabilization andsolidification (s/s) of the sediments. This is done by mixing binder materials with the sediments whichharden and it results in lowered mobility of the contaminants and improved geotechnical properties ofthe soil. If the shear strength is high enough (>140 KPa), the permeability is low enough (10-8-10-9m/s) and the leaching is reduced sufficiently, the stabilized sediments can be used as a foundation.To evaluate the possibility of this remediation method, a batch of sediment samples from the area wasanalyzed to obtain information about site specific parameters. The analysis showed that the sedimentshad high water content and were rich in organic matter. They were dominated by small particlefractions and had a PAH-16 concentration of 13000 mg/kg DM. With regard to these site specificparameters and a literature study, four different recipes with different amounts of binders wereselected and tested in a laboratory study. The used binders were: cement from Skövde which is aportland-fly ash cement, Monofill composed of 20 % cement and 80 % granulated furnace slag, andaddition of activated carbon.The sediments were mixed with binders according to the recipes and left to harden for 28 days.Following the 28 days of hardening, the stabilized mixtures were evaluated with regard to: thereduction of leaching of PAH in comparison to the untreated sediments, shear strength, andpermeability.Analyses of the four mixtures showed that the desirable values of both shear strength and permeabilitywere achieved for all mixtures, and that a higher concentration of binders resulted in a higher shearstrength and lower permeability. The results from the leaching tests indicated that a higherconcentration of activated carbon resulted in a lowered leaching of PAH.The mixture of binders that was deemed to be most suitable for stabilizing the sediments from the areawas a total amount of cement and Monofill at 250 kg/m3 (30 % cement and 70 % Monofill) with anaddition of activated carbon at 5 % of DM (dry matter).Addition of this binder mixture to the sediments resulted in a shear strength of 413 KPa and a desiredlow permeability. The reduced leaching of PAH-16 was ~45 % compared to untreated sediments.
76

Släckvattenpartiklars spridning i mark och grundvatten : En studie av brandgenererade partiklars egenskaper och påverkan på föroreningsspridning / Transport of particles from fire-extinguishing water in soil and groundwater : A characterisation study of fire generated particles and there effect on contamination transport

Iverfelt, Ulrika January 2014 (has links)
Vid brand kan stora mängder med förorenande ämnen och partiklar bildas. Dessa kan, vid släckning av brand med vatten, ge upphov till kontaminerat släckvatten. För att förstå och kunna förutsäga föroreningsspridningen från släckvatten i mark och grundvatten krävs det att släckvattenpartiklars inverkan på föroreningsspridning utreds. Syftet med detta arbete var att öka kunskapen om de kemiska och fysiska egenskaper partiklar i släckvatten uppvisar samt hur partikelegenskaperna påverkar föroreningstransport i vattenmättad mark och grundvatten. Studien har genomförts i form av en fallstudie där släckvattenpartiklar från en enskild brand har undersökts. Utifrån partikelegenskaper finns två mekanismer som kan räknas som styrande för partikeltransport i mark och grundvatten: fysiokemiska partikel- och ytinteraktioner samt silning. Mekanismernas inverkan på partikeltransporten beror bland annat på partiklarnas ytladdning och storlek. För att undersöka släckvattenpartiklarnas egenskaper utfördes analyser av partiklarnas storleksfördelning och zetapotential. För att förstå hur partiklarna påverkade föroreningsspridningen analyserades koncentration polycykliska aromatiska kolväten (PAH) och metaller. Utifrån dessa mätningar genomfördes kolonnförsök där släckvattenpartiklar transporterades genom kiselsand. Resultaten visade att medelvärdet för släckvattenpartiklarnas zetapotential var negativ. Släckvattenproverna som undersöktes innehöll höga koncentrationer av PAH och metaller. Då partiklarna filtrerades till två storleksfraktioner, större och mindre än 11 µm, återfanns högst koncentration PAH och metaller i släckvatten med partiklar > 11 µm. I kolonnförsöken transporterades partiklar med diameter ≤ 11 µm genom kiselsand medan större partiklar permanent immobiliserades. Mätningarna och transportförsöken indikerar att partiklar ≤ 11 µm, i mark med liknande egenskaper och förhållanden som under kolonnförsöken, skulle kunna transporteras utan påverkan av fysiokemiska partikel- och ytinteraktioner. Den avgörande mekanismen för partikeltransport av partiklar med en diameter ≤ 11 µm i vattenmättad mark och grundvatten skulle då vara silning. Släckvattenpartiklarnas transport och på så sätt föroreningsspridningen blir då beroende av markens porstorlek samt partiklarnas diameter. Transportförsöken för partiklar > 11 µm pekade på att fysiokemiska partikel- och ytinteraktioner och/eller silning permanent immobiliserade de större partiklarna. Vid immobilisering av de större partiklarna skulle föroreningsspridning kunna begränsas. För att skapa en fullständig bild över vilka mekanismer som styr släckvattenpartiklarnas transport och på så vis föroreningsspridning under olika förhållanden behöver vidare undersökningar genomföras. / A fire can generate large amounts of toxic compounds and particles. When a fire is extinguished with water these compounds and particles can be transferred to the water, generating contaminated fire-extinguishing water. To understand and predict contamination transport from fire-extinguishing water in soil and groundwater the effect of fire generated particles on contamination transport needs to be understood. The aim of this study was to increase the knowledge of the chemical and physical properties of particles in fire-extinguishing water and to examine how these properties effect contamination transport in soil and groundwater. The study was conducted as a case study where fire-extinguishing water from a single fire was examined. Considering particle properties, particle transport in soil and groundwater is regulated by two main mechanisms: physicochemical particle-surface interactions and straining. How the mechanisms effect the transport is controlled by, among other things, the surface charge of the particles and the size of the particles. To understand particle properties analysis of the size distribution and zeta potential were conducted. To understand how the particles influenced contamination transport concentrations of polycyclic aromatic hydrocarbons (PAH) and metal were measured. Column experiments were then conducted with the characterized particles. The results showed that the particles zeta potential was negative. The fire-extinguishing water contained high concentrations of metals and PAH. When the particles were filtrated into two sizes, larger and smaller than 11 um, the highest concentration PAH and metals were found on the larger particles. In the column experiment particles ≤ 11 µm were transported through the sand while larger particles were immobilized. The measurements and the transport experiments indicate that particles ≤ 11 µm, in soil with similar properties as in the column experiment, could be transported without influence of physicochemical particle-surface interactions. The main mechanism for particle transport for particles with a diameter ≤ 11 µm would then be straining. That means that the transport of particles and therefore contamination transport would depend on particle size and soil pore size. The transport experiment with particles > 11 µm indicated that physicochemical particle-surface interactions and/or straining immobilized larger particles. If larger particles are immobilized the contamination spreading would be limited. To fully understand what mechanism controls the transport of particles in fire-extinguishing water, and therefore the contamination transport, more studies need to be conducted.
77

Nitrifierande mikrobiella samhällen som indikatorer för förorenad jord : Jämförelse av den genetiska och funktionella potentialen / Nitrifying microbial communities as indicators of soil contamination : Comparison of genetic and functional potential

Berkelund, Linn January 2018 (has links)
I Sverige finns det ungefär 25 000 riskklassade förorenade områden samt ännu fler områden som potentiellt är förorenade. Naturvårdsverket har tagit fram generella riktvärden för olika förorenade ämnen. Halter över riktvärdena antyder att risken för negativa effekter på människan eller miljön bedöms vara stor och att efterbehandling av området är aktuellt. Ett vanligt, men kostsamt efterbehandlingsalternativ är urschaktning och bortforsling av jord innehållandes halter av ämnen över riktvärdena. Ett intresse finns för att utveckla lätt tillämpbara metoder för platsspecifik riskbedömning av mark i syfte att skydda markmiljön och dess funktioner. Mikroorganismer som ingår i kvävets kretslopp utför nyckelfunktioner i jorden. Flera studier indikerar att dessa mikroorganismers abundans och aktivitet påverkas av flera olika markföroreningar. Inom forskningsprojektet APPLICERA har ett lysimeterexperiment genomförts där två jordar, med olika egenskaper med avseende på bland annat kornstorleksfördelning och pH (svagt basisk sandy loam respektive sur sand), förorenats med koppar respektive PAH:er i varierande halter. Halterna motsvarar riktvärden för känslig markanvändning (KM), mindre känslig markanvändning (MKM) och 3xMKM. Provtagning av jorden har skett vid tre tillfällen under en period av 16 månader. I detta examensarbete har nitrifierande mikroorganismers potential för att användas som indikatorer för förändrad markfunktion i förorenad jord undersökts. Detta har gjorts genom att kvantifiera ammoniakoxiderande arkéer (AOA), ammoniakoxiderande bakterier (AOB) samt de nitritoxiderande bakteriesläktena Nitrospira och Nitrobacter i jord som provtagits vid de olika tidpunkterna i lysimeterexperimentet. Mätning av potentiell ammoniakoxidation (PAO) har skett för jord från det sista provtagningstillfället. Resultaten visade att abundansen av mikroorganismerna generellt var större i den svagt basiska jorden klassificerad som sandy loam än i den sura jorden klassificerad som sand. Med tiden minskade AOA:s abundans för den högsta koncentrationen av koppar och PAH, särskilt utpräglad var minskningen i den sura jorden. Även Nitrospira minskade i abundans i PAH-förorenad jord för båda jordtyperna, dock kunde en minskning i abundans i kopparförorenad jord statistisk endast säkerställas för den sura jorden. AOB:s och Nitrobacters abundans visade inte på någon tydlig uppåt- eller nedåtgående trend varken över tid eller för ökande föroreningshalt. Skillnaden i kvantitet av mikroorganismer mellan jordtyperna antyder att jordens kemiska och fysiska egenskaper påverkade mikroorganismernas abundans såväl som föroreningarnas biotillgänglighet. PAO minskade med ökande kopparhalt för båda jordtyper, däremot sågs en minskning i PAO med ökande PAH-halt endast i den sura jorden. Resultaten antyder att abundansen av AOA och Nitrospiras verkar ha störst potential att utgöra generella indikatorer över ändrad markfunktion, dock lämpligen med komplettering av förbättrade mätningar av PAO för att få mer information om kvävets kretslopp i förorenad jord. / In Sweden there are around 25,000 contaminated areas classified as a risk for human health or the environment, and even more potentially contaminated areas. The Swedish Environmental Protection Agency has developed generic guideline values for hazardous substances.  Contamination levels exceeding the guideline values indicate a large risk for human health or the environment and that there is a need to remediate the site. A frequently used and expensive aftertreatment is excavation and removal of contaminated soil. Therefore, there is an interest to develop easy applicable methods for site-specific risk assessment with the purpose to protect the soil environment and its functions. Microorganisms involved in the nitrogen cycle perform key functions in soil. Several studies indicate that the abundance and activity of N-cycling microorganisms are sensitive to various soil pollution. Within the research project APPLICERA, a lysimeter experiment was conducted with two different soil types (acidic sandy soil and slightly alkaline sandy loam) and different contamination levels of copper and PAH. The contamination levels corresponded to generic guideline values for sensitive land-use (KM), less sensitive land-use (MKM) and 3xMKM. Soil samples were taken at three times during a period of 16 months. The aim of this master thesis was to investigate nitrifying microorganism potential as indicators for altered soil functioning in contaminated soil. Ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and the nitrite-oxidizing bacteria genera Nitrospira and Nitrobacter has been quantified in soil samples with the different treatments. Measurements of the potential ammonia oxidation (PAO) have been performed in soil from the last sample taking.  The abundance of the nitrifying microorganisms was in general higher in the slightly alkaline sandy loam soil. Over time there was a decrease in AOA abundance for the highest concentration of copper and PAH, most pronounced in the acidic sandy soil. Also, a decrease in the abundance of Nitrospira in soil contaminated with PAHs could be seen for both soil types. In copper contaminated soil a distinct decrease in the abundance of Nitrospira could only be seen in the acidic sandy soil. The abundance of AOB and Nitrobacter did not show any obvious pattern for different contamination levels or over time. The difference in abundance of nitrifying microorganisms between the soil types suggests that the soil’s chemical and physical characteristics as well as the bioavailability of the contaminant affected their abundance. A significant decrease in PAO could be seen for the highest contamination level of copper for both soil types, but for the PAH contaminated soil PAO decreased only in the acidic sandy soil. These results suggest that the abundance of AOA and Nitrospira seems to have greatest potential as general indicators for altered soil functioning. However, improved activity measurements are needed to gain greater insight into the soil N-cycle functioning in contaminated soils.
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Utvärdering av geotextildukar för tillfällig sedimentkontroll : Avseende suspenderat material, PAH samt kvicksilver

Emma, Risén January 2010 (has links)
Geotextildukar används idag som tillfällig kontroll av sedimentgrumling vid vattenarbeten. Syftet med examensarbetet är att ge ökad kunskap kring olika geotextildukars genomsläpplighet med avseende på suspenderat material, PAH (Polycykliska aromatiska kolväten) och kvicksilver vid suspension av sediment från Karlbergskanalen. Detta har gjorts genom en laboration. Resultaten visar att det inom några minuter bildas en filterkaka på de tre undersökta dukarna. Dukarna blir täta då de utsätts för finpartikulärt suspenderat sediment med koncentrationen 57 g/l hämtat från Karlbergskanalen. Under de 2,5 timmar långa försöken har dukarnas permeabilitet kraftigt reducerats. Under laborationen var PAHtot och mängden PAH i den filtrerade fraktionen störst vid turbiditetsmaximum. Den filtrerade fraktionen PAH följde turbiditeten och reducerades med 21 % samtidigt som turbiditeten reducerades med 24 % under försöket. Även den totala kvicksilvermängden var störst vid turbiditetsmaximum, resultaten är dock inte statistiskt säkerställda. Under laborationen gav en högre halt suspenderat material en lägre andel PAH i den filtrerade fraktionen, troligtvis beroende på re-adsorption. För att utvärdera hur stor andel av PAH, kvicksilver, kadmium och koppar som befinner sig i den filtrerade fasen har det genomförts försök där sediment och vatten skakats 3x10 timmar. Av den totala PAH koncentrationen var 0,07 % i den lösta fasen. Endast en låg andel av koppar, kadmium och kvicksilver återfanns i den lösta fasen (< 1 %). Trots den låga andelen i den filtrerade fraktionen skulle motsvarande haltökningar i Karlbergskanalen innebära halter långt över aktuella gränsvärden[1]i dukbassängen. Innan filterkakan bildats sker ingen reduktion av turbiditeten för två av de tre undersökta dukarna. Geotextilskärmarna förhindrar således ingen spridning av miljögifter utan bildningen av en filterkaka. Om filterkakan bildas och består i fält går inte att fastställa utifrån laborationen. [1]MKN MAC för löst Hg och Cd, Naturvårdsverkets föreslagna GV för löst Cu MKN MAC för den totala PAH koncentrationen / Geotextiles are used as temporary sediment controls in water during construction work. The aim of this project is to give background information to a cost effective control program and to increase the knowledge about geotextiles and their permeability for suspended sediment, PAH and Hg for a site specific sediment. Laboratory studies have been conducted in order to evaluate three geotextiles with regard to their ability to separate suspended sediment, PAH and Hg. The results show that a filter cake is formed. The textiles became clogged within a time period of 15 minutes and no sediment passed the textiles after this. A sediment concentration of 57 g/l was used. The separation of suspended particulate matter is 28-78 % and the textile with the greatest reduction capacity was the thinnest one. The separation of PAHtot was 79 %, meanwhile the average separation of suspended sediments was 78 %. The geotextile did not reduce the dissolved fraction of PAH. This fraction was larger on the outside suggesting that the concentration of suspended material was too low to re-adsorb the dissolved PAH. The turbidity decreased with 24 % during the experiment due to sedimentation, the dissolved fraction of PAH was reduced with 21 % during the same time period. The amount of Hgtot was largest at turbidity maximum. Laboratory experiments where sediment was shaken 3x10 hours with distilled water have also been conducted in order to evaluate the amounts of PAH, Hg, Cu and Cd that partition in the dissolved phase. 0, 07 % of the total amount of PAH was found in the filtered phase and only small fractions of Cu, Cd and Hg (< 1 %). Despite the small percentage in the filtered fractions the corresponding increase in Karlbergskanalen would result in concentrations well above maximum allowed concentrations[1]in the geotextile encircled area. There is no reduction of the turbidity before the filter cake is formed. It is not possible to draw any conclusions about the formation of a filter cake in field and if a formed filter cake would be broken by hydraulic forces or not. [1]MKN MAC for dissolved Hg and Cd, Swedish Environmental Protection Agency’s suggested limit value for dissolved Cu, MKN MAC for the total PAH concentration
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Pollutant profiles as tools for characterisation of environmental exposure

Wingfors, Håkan January 2004 (has links)
This thesis is concerned with measurements of persistent organic pollutants (POPs) in environmental samples. The POPs consist of several groups of compound with many isomers, hence analysing POPs in a complex environment is a This thesis is concerned with measurements of persistent organic pollutants (POPs) in environmental samples. The POPs consist of several groups of compound with many isomers, hence analysing POPs in a complex environment is a challenging task. Studies of the abundance or dynamics of such substances in the environment require careful consideration of several key steps. The environmental and analytical problems must be correctly defined, suitable analytes, sampling strategies and techniques must be selected, the chemical analyses must be reproducible and accurate, and the data evaluation protocols must be rigorous and appropriate. The aim of this thesis was to evaluate the use of pollutant profiles in order to assess complex patterns of environmental exposure. When combined with multivariate data analysis (MVDA) a maximum of information may be extracted from analytical data. Nevertheless, good quality data is essential for correct evaluation of the environmental phenomena under investigation. The precision and accuracy of a solid phase assisted liquid extraction method was therefore assessed by comparison to a reference method. The validated method was used in two human exposure studies. The concentrations of PCBs and dioxins were determined in human tissues from general populations in Sweden and Spain. Although it was concluded that the populations were exposed to similar degree to PCBs and dioxins, principal component analysis (PCA) showed that the compound profiles differed between the populations. PCA was also used to differentiate between occupationally exposed workers and matched controls and between exposed workers with recent and earlier exposure. In addition, the analysis indicated that the differences in PCB patterns in workers with recent and earlier exposure were related to differences in the metabolic degradation rates of individual PCBs. The PCA model was further used to select PCB congeners that were representative of each group. Finally, the emission of polycyclic aromatic hydrocarbons (PAHs) in a traffic tunnel was estimated by measuring 29 individual PAHs. The sampling periods were chosen to reflect a maximum variation in the traffic composition. An excellent prediction of the percentage of heavy-duty vehicles was obtained using partial least squares (PLS) regression. It was shown by PCA that it might be possible to predict source compositions at other locations with the aid of multivariate statistical tools. Thus, properly gathered pollutant profiles and MVDA may be combined to extract a large amount of significant information from environmental source and exposure data.
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Mécanismes moléculaires de tolérance des plantes aux xénobiotiques : application à la phytoremédiation des hydrocarbures aromatiques polycycliques (HAPs) / Molecular mechanism of plants tolerance to xenobiotics : application to phytoremediation of polycyclic aromatic hydrocarbons

Dumas, Anne-Sophie 05 December 2013 (has links)
L'ingénierie écologique a permis l'émergence de nouvelles technologies telles que la phytoremédiation, une approche de dépollution des sols basée sur l'utilisation des plantes. Cependant, jusqu'à présent, les mécanismes physiologiques et moléculaires qui contrôlent la dégradation des polluants organiques, en particulier les HAPs, restent très mal documentés chez les plantes supérieures. Dans ce travail, une approche intégrative et un profilage trancriptomique à l'échelle du génome entier ont permis d'étudier les premiers événements moléculaires impliqués dans la réponse, chez les plantes, à un stress provoqué par le phénanthrène. Un réseau de gènes susceptibles d'intervenir dans la perception, la dégradation et/ou la transformation des HAPs en molécules moins dangereuses a ainsi été identifié. D'autre part, nous avons pu montrer que le saccharose induit une tolérance à ce polluant, qui se traduit (i) par une activité transcriptionnelle très rapide, ce qui suggère un effet signalétique, (ii) une reconfiguration importante à l'échelle transcriptionnelle du génome exprimé, qui conduit à une mise en place des voies métaboliques de production d'énergie, de détoxification et de réparation cellulaire. Parallèlement, un site pilote de dépollution a été conçu et mis en œuvre, en exploitant les données obtenues au laboratoire. Cette expérimentation, sur deux ans, nous a permis de comparer l'efficacité de plusieurs espèces végétales mais aussi de tester l'effet protecteur du saccharose in-situ. Malgré l'obtention de résultats contrastés, cette étude confirme l'incidence de la nature des espèces végétales et des pratiques culturales sur l'efficacité de cette méthode de dépollution. Elle souligne également le rôle important de l'interaction plante-microorganismes du sol. / Ecological engineering strategies allowed the emergence of new technologies such as phytoremediation to clean up environmental pollution. Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous and hazardous molecules for natural ecosystems and human health. However, molecular mechanisms involved in PAHs detoxification in plant remain largely unknown. This work allowed to decipher the early plant response of phenanthrene induced stress through an integrative investigation using wide genome transcriptomic and targeted metabolomic approaches. Hence, a gene network was identified to be involved in the early perception and signalization of PAHs and putative degradation and/or transformation to harmless molecules. Additionally, we showed that sucrose mitigate phenanthrene induced stress, while Arabidopsis development was arrested and seedlings were unable to accumulate chlorophyll in the presence of high phenanthrene concentration, sucrose allowed growth and chlorophyll accumulation. These phenotypical changes were associated with (i) very early transcriptional regulation, suggesting a sucrose signaling effect (ii) reconfiguration of wide genome transcriptional changes, as metabolic, detoxification and cell repair pathways were induced. In parallel, based on previous results accumulated in controlled conditions. Field investigation allowed the evaluation of the ability of different plant species to clean up PAHs polluted soil. We also evaluate the impact of sucrose supply on natural phytoremediation efficiency. Despite contrasted results, this study confirms the incidence of the plant species and the cultural practices on the efficiency of this method. It also underlines the role of soil microorganisms and plant interactions.

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