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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.
21

Exponering för bromerade flamskyddsmedel vid arbete med flygplansunderhåll

Lundgren, Håkan January 2013 (has links)
Problemställning och syfte: Bromerade flamskyddsmedel (BFR) används i många varor och produkter. Polybromerade difenyletrar (PBDEs) är en av dessa och deras kemiska struktur liknar den i miljögiftet PCB och kan på samma sätt lagras upp i miljön samt skada människor och djur. På arbetsplatser där BFR förekommer riskerar medarbetarna att exponeras. I den här studien har olika BFR undersökts i samband med servicearbete på flygplan. Målet har varit att jämföra förekomsten i damm och luft, samt blod (serum) med resultat från tidi­gare studier. Metod: Damm- och luftprovtagning har genomförts vid olika faser av service­arbetet. Proverna har analyserats med avseende på olika typer av BRF. Dess­utom har medarbetarnas upptag av BRF via blodprov (serum) undersökts. Resultat: Undersökningen har visat att samtliga former av PBDE samt övriga BFR förekommer i höga koncentrationer i damm och luft i flygplanen, men med ojämn fördelning. Analyserna av serum visade att flygmekanikerna har förhöjda nivåer jämfört med svensk allmänhet och jämförbar nivå med högexponerade yrkesgrupper. Medarbetarnas ålder, år i yrke och arbetad tid i flygplan den senaste månaden uppvisade inget samband i förhållande till PBDE i serum. Slutsats: Koncentrationerna av BFR i damm och luft är högre än i de flesta andra miljöer och koncentrationerna i serum är högre än de flesta referens­gruppers. För att minska risken för exponering behöver insatserna för att mini­mera dammet via städning förbättras. Dessutom bör informationen gällande hygien och användning av personlig skyddsutrustning repeteras för medarbe­tarna. Samtliga yrkeshygieniska åtgärder bör fastställas och hanteras i det systematiska arbetsmiljöarbetet via rutiner och handlingsplaner. / Presentation and aim: Brominated flame retardants (BFRs) are used in many materials and products. Polybrominated diphenyl ethers (PBDEs) are the most well known and because of their structures, similar to that of PCB, they have been proposed to possibly affect health and environment. Occupational exposure has been an issue for years and this study investigated BRF in aircraft mainte­nance. The aim of this study was to assess the presence and levels of BRFs in dust, air and blood (serum) and compare the results with different references. Method: Dust and air were sampled in different phases of the work with the air­craft and analysis of a spectrum of BFR was performed. In addition, serum from employees was sampled and analyzed for the presence of PBDEs. Result: PBDEs and other BFRs were found in dust and air samples at high con­centrations. Serum concentrations in the technicians were slightly higher to those observed in the general Swedish population and in the same magnitude as some highly exposed occupational references. Years of work, age or time spent in the aircraft before giving blood seems not to have an impact on the level of BFRs in serum. Conclusion: This study shows high concentrations of BFR in dust and air in the aircraft and the concentrations of PBDEs in serum were high compared to most reference groups. To minimize the risk for exposure, it is important to focus on industrial hygiene improvements to minimize the amount of dust in working areas. The personal hygiene and use of personal safety equipment can also be improved and the routines should be described and included in the appropriate documentation regarding work environment.
22

Pollutants associated with mass mortality of Nile crocodiles (Crocodylus niloticus) in the Kruger National Park, South Africa / P.L. Booyens

Booyens, Paul Lodewyk January 2011 (has links)
The first of a series of mass mortalities of Nile crocodiles in the Olifants and Letaba rivers in the Kruger National Park (KNP) was reported in the winter of 2008. The present study investigated the levels and possible effects on eggshell thickness of inorganic elements and organic pollutants in Nile crocodile eggs from these rivers, and comparing them with eggs from a reference crocodile farm and a reference dam inside the KNP. The egg contents were analyzed for chlorinated organic compounds and brominated flame retardants. Eggshells and egg contents were analyzed for inorganic elements. The elemental concentrations in the eggshells and contents were low when compared with previous studies. The highest concentrations were found in the eggs from the reference crocodile farm. The eggs from the reference dam and the crocodile farm had thicker shells, and the eggs from the Olifants and Letaba rivers had thinner shells. Not all eggs in a female develop at the same rate, while eggshell formation presumably occurs at the same time for all eggs. As a result, the elemental profile of egg contents may differ between eggs of the same clutch, but less so for the shells. Weak or no associations were found between the elemental concentrations of the content and eggshells and eggshell thinning. A possible organic pollutant–induced eggshell thinning effect was found. The compounds found were not at levels that could have caused the mortalities, but may affect the sex ratios through endocrine disruption. Further studies are therefore required. / Thesis (M.Sc (Environmental Science))--North-West University, Potchefstroom Campus, 2011.
23

Pollutants associated with mass mortality of Nile crocodiles (Crocodylus niloticus) in the Kruger National Park, South Africa / P.L. Booyens

Booyens, Paul Lodewyk January 2011 (has links)
The first of a series of mass mortalities of Nile crocodiles in the Olifants and Letaba rivers in the Kruger National Park (KNP) was reported in the winter of 2008. The present study investigated the levels and possible effects on eggshell thickness of inorganic elements and organic pollutants in Nile crocodile eggs from these rivers, and comparing them with eggs from a reference crocodile farm and a reference dam inside the KNP. The egg contents were analyzed for chlorinated organic compounds and brominated flame retardants. Eggshells and egg contents were analyzed for inorganic elements. The elemental concentrations in the eggshells and contents were low when compared with previous studies. The highest concentrations were found in the eggs from the reference crocodile farm. The eggs from the reference dam and the crocodile farm had thicker shells, and the eggs from the Olifants and Letaba rivers had thinner shells. Not all eggs in a female develop at the same rate, while eggshell formation presumably occurs at the same time for all eggs. As a result, the elemental profile of egg contents may differ between eggs of the same clutch, but less so for the shells. Weak or no associations were found between the elemental concentrations of the content and eggshells and eggshell thinning. A possible organic pollutant–induced eggshell thinning effect was found. The compounds found were not at levels that could have caused the mortalities, but may affect the sex ratios through endocrine disruption. Further studies are therefore required. / Thesis (M.Sc (Environmental Science))--North-West University, Potchefstroom Campus, 2011.
24

Transfer and effects of brominated flame retardants (BFRs) on three plant species and one earthworm species in anthroposoils / Transfert et effets des retardateurs de flamme bromés (RFBs) sur trois espèces végétales et une espèce de lombric dans des anthroposols

Coelho Macedo, Cláudia Filipa 30 September 2019 (has links)
Une étude approfondie a été menée dans deux zones distinctes (Estarreja au Portugal, noté EST, et Casier Peyraud 6 en France, noté PEY) pour évaluer les niveaux de contamination, ainsi que leurs comportements dans des anthroposols et les risques potentiels de ces contaminants pour des organismes vivants du sol. L’objectif principal étant d’évaluer la mobilité environnementale des retardateurs de flamme bromés (RFBs) dans un écosystème terrestre, notamment vers les vers de terre (Eisenia fetida) et les plants (luzerne (Medicago sativa), cresson (Nasturtium officinale), moutarde blanche (Sinapsis alba), dans une prospective d’évaluation du risque de transferts de ces molécules.Le facteur de bioaccumulation (BAF) ainsi que les indices SET et ERITME ont été calculés. Le BAF permet de déterminer si une substance est accumulée dans un organisme donné et s’il existe un risque d’entrée et de diffusion tout au long de la chaine alimentaire. Les indices SET et ERITME permettent de classer les sites testés en fonction du transfert efficace des COs par les anthroposols aux organismes testés, et d’avoir une idée du risque potentiel pour l’écosystème. L’indice SET donne une idée globale de l’excès de transfert pour tous les contaminants dans les matrices étudiées. L’indice ERITME permet d’évaluer le risque environnemental global inhérent associé à l’excès de transfert des contaminants considérés. Compte tenu des valeurs ERITME, les matrices étudiées peuvent être classées dans un ordre de toxicité qui est aussi conforme pour l’ensemble des organismes testés (E. fetida, luzerne, cresson et moutarde). / A comprehensive study was conducted in two distinct areas (Estarreja in Portugal, noted EST, and Casier Peyraud 6 in France, noted PEY) to assess the contamination levels as well as their behavior in soils and the potential risks posed by these contaminants to soil organisms. The principal aim was to evaluate the environmental mobility of brominated flame retardants (BFRs) in a terrestrial ecosystem, namely to earthworms (Eisenia fetida) and plants (alfalfa (Medicago sativa), watercress (Nasturtium officinale) and white mustard (Sinapis alba)), concerning the BFRs transfer risk evaluation. The Bioaccumulation factor (BAF) as well as the SET and ERITME indexes were calculated. The BAF allow to determine if a substance is accumulated in a certain organism and if there exists the risk of entry and diffusion along the food chain. SET and ERITME indexes allow to rank the tested sites according to the effective OCs transfer from anthroposoils to the tested organisms and have an idea of the potential risk to the ec system. The SET index gives a global idea of the excess of transfer for all the contaminants in the studied matrices. The ERITME index allows to evaluate the possible inherent global environmental risk associated with the excess of transfer on the considered contaminants. Considering the ERITME values, the studied matrices can be classified in an apparent increasing order of toxicity that it is also in accordance with the levels of OCs found in the all the tested organisms (E. fetida, alfalfa, cress and mustard).
25

Retardéry hoření a jejich průnik do terestrického ekosystému / Flame retardants and their penetration into the terrestrial ecosystem

Chytil, Václav January 2014 (has links)
This diploma thesis was focused on the analysis of four compounds from brominated flame retardants group, namely pentabromoethylbenzene, hexabromocyclododecane, hexabromobenzene and tetrabromobisphenol A. Matrices were represented by four soil samples and four seat of fire samples. In addition, bisphenol A was also determined. First of all, process of extraction of analytes from matrices was optimized. Three different extraction techniques were tested (pressurized solvent extraction, microwave-assisted extraction and ultrasound-assisted extraction). Next step was to verify stability of target compounds in strongly acidic conditions and to optimize clean-up of extract by column chromatography. Gas chromatography with electron capture detection (GC-ECD) was chosen as an appropriate analytical method for the determination of brominated flame retardants. Bisphenol A was determined by gas chromatography with mass spectrometric detection (GC-MS). The derivatization of phenolic analytes before their final analytical determination was also essential.

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