In recent years considerable attention is paid to problems of brominated flame retardants (BFR's – Brominated Flame retardants), which are a diverse group of organic compounds. Even in the recent past have been the most often represented group particularly polybrominated diphenyl ethers (PBDEs), which have found wide use in many industrial sectors. The reason of aplication of these substances is the ability to slow down the combustion process and reduce the risk of ignition by the excessive heating of material. On the other hand, serious concerns about the use of PBDEs was added. The most serious trouble is particular their possible to release from consumer products during their normal use, toxicity and high persistence in parts of environment. Some of these contaminants are more characterized by a high degree of accumulation in biological systems. In this work by several sub-studies the issue of assessment the level of pollution of the aquatic ecosystem of selected localities of the Czech Republic just PBDEs was addressed. One of objectives was monitored the situation of breeding ponds near the village Záhlinice in Central Moravia. Here was assessed level of contamination in fish and birds as two consecutive segments of food chain. The obtained results largely confirmed the assumption that with increasing trophic level of organisms leads to bioaccumulation and thus also higher findings. For comparison, the capture of fish and birds in other localities of the CR was also implemented. In Bartošovice and Hustopeče nad Becvou levels at the buzzard and heron were detected as comparable. The cormorants of the order higher levels of PBDEs were found. Further were also evaluated levels of PBDEs detected in individuals of bioindicator kind of chub caught in two locations on the river Svratka in spring and autumn. Findings of PBDE in muscle, skin and intestines were compared. The obtained results show that between tissues and sites wasn’t significant variability respectively and the findings of controlled substances are practically comparable. With aim to determine the dependence of the concentration of PBDEs in organisms on the length of the river was conducted monitoring of Vír and Brno water reservoirs. In both locations was main monitored kind of bream, which was completed by the other species. The results of the analysis indicate a higher total concentration at the lower part of river Svratka. Differences were also the distribution of individual congeners in both sampling locations. For monitoring of terrestrial system contamination levels of PBDEs has been selected several types of plant bioindicators. These are mainly pine needles (Scots pine, Eastern white pine, Silver fir, Blue spruce) collected from different localities of the Czech Republic. Other matrices were chosen roughages (Common wheat, Naked barley, Alfalfa wheat, Red clover) and oilseeds (Rapeseed) from the Novy Jicin, where Agriculture plant school of the University of Veterinary and Pharmaceutical Sciences Brno. Detected values of PBDE concentrations were very low, generally ranged at the detection limits of the analytical method.

<p>This thesis is based on studies in which the suitability of various gas chromatography (GC) injection techniques was examined for the determination of polybrominated diphenyl ethers (PBDEs) and carbazoles, two groups of compounds that are thermally labile and/or have high boiling-points. For such substances, it is essential to introduce the samples into the GC system in an appropriate way to avoid degradation and other potential problems. In addition, different types of gas chromatographic column system and mass spectrometric detectors were evaluated for the determination of PBDEs.</p><p>Conventional injectors, such as splitless, on-column and programmed temperature vaporizing (PTV) injectors were evaluated and optimized for determination of PBDEs. The results show on-column injection to be the best option, providing low discrimination and high precision. The splitless injector is commonly used for “dirty” samples. However, it is not suitable for determination of the high molecular weight congeners, since it tends to discriminate against them and promote their degradation, leading to poor precision and accuracy. The PTV injector appears to be a more suitable alternative. The use of liners reduces problems associated with potential interferents such as polar compounds and lipids and compared to the hot splitless injector, it provides gentler solvent evaporation, due to its temperature programming feature, leading to low discrimination and variance.</p><p>Increasing the injection volume from the conventional 1-3 µL to >50 µL offers two main benefits. Firstly, the overall detection and quantification limits are decreased, since the entire sample extract can be injected into the GC system. Secondly, large volume injections enable hyphenation of preceding techniques such as liquid chromatography (LC), solid phase extraction and other kinds of extraction. Large-volume injections were utilized and optimized in the studies included in this thesis.</p><p>With a loop-type injector/interface large sample volumes can be injected on-column providing low risk of discrimination against compounds with low volatility. This injector was used for the determination of PBDEs in air and as an interface for the determination of carbazoles by LC-GC. Peak distortion is a frequently encountered problem associated with this type of injector that was addressed and solved during the work underlying this thesis.</p><p>The PTV can be used as a large volume injector, in so-called solvent vent mode. This technique was evaluated for the determination of PBDEs and as an interface for coupling dynamic sonication-assisted solvent extraction online to GC. The results show that careful optimization of the injection parameters is required, but also that the PTV is robust and yields reproducible results.</p><p>PBDEs are commonly detected using mass spectrometry in electron capture negative ionization (ECNI) mode, monitoring bromine ions (m/z 79 and 81). The mass spectrometric properties of the fully brominated diphenyl ether, BDE-209, have been investigated. A high molecular weight fragment at m/z 486/488 enables the use of 13C-labeled BDE-209 as an internal surrogate standard.</p>

This thesis is based on studies in which the suitability of various gas chromatography (GC) injection techniques was examined for the determination of polybrominated diphenyl ethers (PBDEs) and carbazoles, two groups of compounds that are thermally labile and/or have high boiling-points. For such substances, it is essential to introduce the samples into the GC system in an appropriate way to avoid degradation and other potential problems. In addition, different types of gas chromatographic column system and mass spectrometric detectors were evaluated for the determination of PBDEs. Conventional injectors, such as splitless, on-column and programmed temperature vaporizing (PTV) injectors were evaluated and optimized for determination of PBDEs. The results show on-column injection to be the best option, providing low discrimination and high precision. The splitless injector is commonly used for “dirty” samples. However, it is not suitable for determination of the high molecular weight congeners, since it tends to discriminate against them and promote their degradation, leading to poor precision and accuracy. The PTV injector appears to be a more suitable alternative. The use of liners reduces problems associated with potential interferents such as polar compounds and lipids and compared to the hot splitless injector, it provides gentler solvent evaporation, due to its temperature programming feature, leading to low discrimination and variance. Increasing the injection volume from the conventional 1-3 µL to &gt;50 µL offers two main benefits. Firstly, the overall detection and quantification limits are decreased, since the entire sample extract can be injected into the GC system. Secondly, large volume injections enable hyphenation of preceding techniques such as liquid chromatography (LC), solid phase extraction and other kinds of extraction. Large-volume injections were utilized and optimized in the studies included in this thesis. With a loop-type injector/interface large sample volumes can be injected on-column providing low risk of discrimination against compounds with low volatility. This injector was used for the determination of PBDEs in air and as an interface for the determination of carbazoles by LC-GC. Peak distortion is a frequently encountered problem associated with this type of injector that was addressed and solved during the work underlying this thesis. The PTV can be used as a large volume injector, in so-called solvent vent mode. This technique was evaluated for the determination of PBDEs and as an interface for coupling dynamic sonication-assisted solvent extraction online to GC. The results show that careful optimization of the injection parameters is required, but also that the PTV is robust and yields reproducible results. PBDEs are commonly detected using mass spectrometry in electron capture negative ionization (ECNI) mode, monitoring bromine ions (m/z 79 and 81). The mass spectrometric properties of the fully brominated diphenyl ether, BDE-209, have been investigated. A high molecular weight fragment at m/z 486/488 enables the use of 13C-labeled BDE-209 as an internal surrogate standard.

Polybrominated diphenyl ethers (PBDEs) have been intensively used as flame retardants (FRs) and have become ubiquitous environmental pollutants. PBDEs form hydroxylated PBDEs (OH-PBDEs) as metabolites. Further, some OH-PBDEs and methoxy-PBDEs (MeO-PBDEs) are natural products. These are all compounds of environmental and health concern and it is therefore important to confirm their identity and to assess their environmental levels and toxicities. Hence, it is vital to obtain authentic reference standards of individual PBDEs and OH/MeO-PBDEs. The thesis main aim was to develop synthesis methods of congener specific PBDEs, OH- and MeO-PBDEs. The second aim was to identify and quantify PBDEs, OH- and MeO-PBDEs in environmental samples. The third was to propose an abbreviation system for FRs. O-Arylation of brominated phenols, using either symmetrical or unsymmetrical brominated diphenyliodonium salts, was selected for synthesis of PBDEs and OH-/MeO-PBDEs. A total of 16 MeO-PBDEs, 11 OH-PBDEs, 1 diMeO-PBDE and 1 EtO-MeO-PBDE were synthesised. Three novel unsymmetrical diaryliodonium triflates were synthesised and used in synthesis. Optimisations were made to construct a reliable general method for congener specific PBDE synthesis, which was used in the synthesis of 8 representative PBDE congeners. The products were generally characterised by electron ionisation mass spectrometry (EIMS) and nuclear magnetic resonance (NMR) spectroscopy. Identification of PBDEs and OH-PBDEs in various matrixes was based on gas chromatographic and mass spectrometric analyses. Fourteen OH-PBDE congeners were identified in a pooled human blood sample. One previously uncharacterised natural PBDE analogue was identified as 6-OH-6’-MeO-BDE-194, and quantified in Swedish blue mussels. PBDE congeners and other BFRs were identified and quantified in workers and dust from a smelter in Sweden. A structured and practical abbreviation system was developed for halogen- and phosphorus containing FRs. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Submitted. Paper 4: Manuscript.</p>

The dietary intake of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) have been estimated for Swedish children. A dietary survey performed in 2003, including 4, 8-9 and 11-12 year olds, and concentrations in individual food items were combined. The food included in the study was mainly of animal origin, consisting of fish and shellfish, dairy products, meat products, eggs, animal and vegetable fats and fats from miscellaneous food products. The medium-bound intake of PBDEs (9 congeners) were estimated to 23.0 ng/day, 30.9 ng/day and 27.7 ng/day for 4, 8-9 and 11-12 years olds respectively. The corresponding estimations for HBCD were 7.94 ng/day 10.7 ng/day and 9.46 ng/day for 4, 8-9 and 11-12 years olds respectively. These results show a higher daily intake for 8-9 year olds compared with the other age groups. However, when estimating the daily intake per kg bw, the intake decreases with age. BDE-47 contributed the most to the total intake of PBDEs, with approximately 40%. The food group contributing the most to the intake of PBDEs and HBCD was fish and shellfish, of which non-Baltic fatty fish was the largest contributor. There were no considerable differences between boys and girls in any of the aspects examined. The result from this study show a lower intake of PBDEs and HBCD in Swedish children compared with children in other studies made in Europe and the United States. / Bromerade flamskyddsmedel används för att skydda brännbara material från att fatta eld, till exempel skyddas textilier och plaster i bland annat elektronik, fordon och möbler. Två typer av bromerade flamskyddsmedel är polybromerade difenyletrar (PBDE) och hexabromocyklododekan (HBCD). Dessa är additiva flamskyddsmedel och blandas i materialet som ska skyddas men binder inte in i produkten och kan därför lätt läcka ut i miljön, vilket också har skett. Halter har påträffats i miljön och i biota långt från plaster där ämnena produceras eller används. PBDE och HBCD har visats ha hormonstörande och neurotoxiska effekter i studier på råtta och mus. Thyroxinnivåerna sjunker vid exponering av PBDE och HBCD, vilket skulle kunna leda till sköldkörtelproblem och störd utveckling av bland annat hjärnan om exponering sker perinatalt. De neurotoxiska effekterna inkluderar inlärnings- och minnessvårigheter och ett förändrat beteende med hyper- och hypoaktivitet som följd. Human exponering för PBDE och HBCD sker främst via födan och speciellt via animaliska produkter då dessa ämnen är lipofila, bioackumulerande och ofta biomagnifierande vilket gör att de påträffas i högre koncentrationer högre upp i trofinivåerna. Studier från bland annat Sverige och Finland visar att fisk och skaldjur är den största källan till intag av PBDE. De flesta intagsberäkningar av PBDE och HBCD baseras på livsmedelskonsumtionen hos vuxna och visar följaktligen endast hur intaget ser ut för den delen av populationen. För barn, som är en av de känsligaste grupperna i populationen, finns inte många studier att tillgå, varken från Sverige eller andra delar av världen. I den här studien har därför intaget av PBDE (summan av 9 kongener) och HBCD beräknats för barn i Sverige. I en rikstäckande kostundersökning utförd 2003 deltog barn i åldrarna 4, 8-9 och 11-12 år. De fick i en matdagbok ange sin konsumtion under fyra på varandra följande dagar. Data från denna undersökning kombinerades sedan med haltdata från olika livsmedel för att räkna ut intaget av PBDE och HBCD på individbasis. Undersökningen innefattade främst animaliska livsmedel och innehöll därför fisk och skaldjur, mejeriprodukter, köttprodukter, ägg, animaliskt och vegetabiliskt fett och fett från övriga livsmedel. Resultaten visar att födointaget av PBDE var 23,0 ng/dag, 30,9 ng/dag och 27,7 ng/dag för 4, 8-9 respektive 11-12 åringar. Intaget av HBCD beräknades till 7,94 ng/dag, 10,7 ng/dag och 9,46 ng/dag för 4, 8-9 respektive 11-12 åringar. Detta visar att 8-9 åringar har det högsta dagliga intaget av PBDE och HBCD. När intaget beräknas på kroppsvikt däremot, har de yngsta barnen det högsta intaget som sedan sjunker med åldern. Fisk och skaldjur var den största källan till intaget av PBDE och HBCD, trots att konsumtionen av dessa livsmedel var relativt lågt. Det fanns ingen större skillnad mellan pojkar och flickor, varken i intag av PBDE eller av HBCD. Jämfört med de få studier som gjorts i andra länder, är det tydligt att svenska barn har ett lägre intag av PBDE och HBCD. Undersökningen tyder också på att intaget av PBDE och HBCD hos svenska barn, utifrån de kunskaper vi har idag, inte utgör någon risk med avseende på de effekter av PBDE och HBCD som påträffats i toxikologiska studier. Däremot är barn i ett känsligt skede i livet och upprepad exponering samt exponering för flera miljögifter samtidigt skulle kunna påverka deras utveckling negativt.

Water is one of the most abundant substances on Earth and it is an essential part of our lives. Its pollution has an impact on the whole ecosystem. Polybrominated diphenyl ethersare synthetic persistent organic pollutants used as flame retardants in various commercial and household products. This thesis is focused on assesing the degree of elimination of PBDEs in wastewater treatment plants with different technological processes of purification. The samples were collected in the three wastewater treatment plants in the south-moravian region, that means WTP Brno – Modřice, WTP Mikulov and WTP in VFU Brno.

Brominated flame retardants (BFRs) are chemicals used in e.g. electronic equipment, textiles and plastics for the prevention of fire. Over recent decades, concern has been raised regarding some heavily used BFRs, since the levels in the environment have been increasing. In the present thesis, persistent, bioaccumulative, and toxic (PBT) properties were studied for a structurally varied set of BFRs selected to represent more than 60 organic BFRs. The studied BFRs include: 2,4,4'-tribromodiphenyl ether (BDE 28), 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE  183), decabromodiphenyl ether (BDE 209), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), tetrabromobisphenol A 2-hydroxyethyl ether (TBBPA OHEE), 2,4,6-tribromophenol (246BrPh), 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH), and hexabromobenzene (HxBrBz). It is likely that soil will act as a sink for BFRs. Therefore, studies of BFRs were performed on persistence in soil, and on bioaccumulation from soil in the earthworm Eisenia fetida. Large variation in the biodegradability in soil among the tested BFRs was observed. The studied brominated diphenyl ethers (BDE 28 and BDE 209) were very persistent under both aerobic and anaerobic conditions, while 246BrPh and TBECH degraded quickly in both aerobic and anaerobic soil. The bioaccumulation in earthworm from soil was high for HxBrBz, TBECH and for tested brominated diphenyl ethers with 4-6 bromine atoms (BDE 47, BDE 99, and BDE 153). Bioaccumulation was also studied in zebrafish after dietary exposure to a mixture of BFRs. It was shown that several metabolites were formed and retained in zebrafish, which highlights the importance of also searching for and identifying persistent degradation products. Maternal transfer was shown for all BFRs present in the female zebrafish. This shows that zebrafish young (fry) are exposed to these BFRs at approximately the same concentrations as female zebrafish during the early-life stages, when fish are usually most sensitive to organic contaminants. Toxicity of individual BFRs and a BFR mixture was studied in Nitocra spinipes using a silica gel-based system. Highest toxicities were observed for BDE 28, TBBPA, and TBBPA OHEE. In the mixture toxicity study, simultaneous exposure to low concentrations (individually causing no significant effect) of six BFRs significantly affected the survival of Nitocra spinipes. The results from the PBT studies presented in the thesis and literature data were compared with the criteria for PBT classification, as set in the European REACH legislation. Further, some BFRs with physico-chemical properties similar to those of identified PBTs were suggested to be prioritized for future PBT testing.

Polybrominated dibenzo-p-dioxins (PBDD) and dibenzofurans (PBDF) are a group of compounds of emerging interest as potential environmental stressors. Their structures as well as toxic responses are similar to the highly characterized toxicants polychlorinated dibenzo-p-dioxins. High levels of PBDDs have been found in algae, shellfish, and fish, also from remote areas in theBaltic Sea. This thesis presents studies on PBDD behavior in fish and offspring, and natural formation of PBDDs from naturally abundant phenolic precursors. The uptake, elimination, and maternal transfer of mono- to tetraBDD/Fs were investigated in an exposure study reported in Paper I. The effects of PBDDs in fish were examined in a dose-response study (Paper II). It was shown that fish can assimilate PBDD/Fs from their feed, although non-laterally substituted congeners were rapidly eliminated. Laterally substituted congeners were retained as was congeners without vicinal hydrogens to some extent. PBDD/Fs were transferred to eggs, and congeners that were rapidly eliminated in fish showed a higher transfer ratio to eggs. Exposure to the laterally substituted 2,3,7,8-TeBDD had significant effects on the health, gene expression and several reproduction end-points of zebrafish, even at the lowest dose applied. The geographical and temporal variations of PBDD in biota samples from the Baltic Seasuggest biogenic rather than anthropogenic origin. In Paper III, bromoperoxidase-mediated coupling of 2,4,6-tribromophenol yielded several PBDD congeners, some formed after rearrangement. The overall yield was low, but significantly higher at low temperature, and the product profile obtained was similar to congener profiles found in biota from the Swedish West Coast. In Paper IV, photo­chemi­cally induced cyclization of hydroxylated polybrominated diphenyl ethers under natural conditions produced PBDDs at percentage yield. Rearranged products were not detected, and some abundant congeners do not seem to be formed this way. However, the product profile obtained was similar to congener profiles found in biota from the Baltic Proper. Since the PBDD congeners found in biota have a high turn-over in fish, the exposure must be high and continuous to yield the PBDD levels measured in wild fish. Thus, PBDDs must presumably be formed by common precursors in general processes, such as via enzymatic oxidations, UV-initiated reactions or a combination of both. The presented pathways for formation of PBDDs are both likely sensitive to changes in climatic conditions.

Persistent organic pollutants (POPs) are hydrophobic substances that readily sorb to organic matter in particles and colloids instead of being freely dissolved in the water phase. This sorption affects the bio­availability and environmental transport of the POPs. The major part of this thesis concerns the role of sediments as secondary sources of POPs. As the primary emissions decrease, contaminated sediments where POPs have accumulated can become the main source of contamination. If the contaminated sediment by time becomes covered with cleaner layers, the POPs are buried and no longer in contact with the aquatic environment. Experiments in this thesis showed, however, that new invading species can alter the sediment-water dynamics as a result of their bioturbation, i.e. mixing of sediment particles and pore-water. Marenzelleria spp., invading species in the Baltic Sea that burrow deeper than native species, were found to increase the remobilization of buried contaminants. The sediment-to-water flux was inversely related to the burial depth (2-10 cm) of the POP congeners (polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers) and also inversely related to the hydrophobicity of the congener. The flux was therefore most pronounced for less hydrophobic contaminants, which was linked to the bioirrigating behaviour of these species. Marenzelleria spp. also accumulated the buried POPs and increased concentrations in surface sedi­ment. Contaminants previously considered buried at a ’safe’ depth can thus be remobilized as a result of the invasion of Marenzelleria spp. in the Baltic Sea. One method to decrease the remobilization of contaminants from sediments is ’capping’, i.e. a layer of clean material is placed as a cap on the sediment. By amending the cap with active materials, which sequester the POPs and decrease their availability, thinner layers can be used (’active capping’ or ’thin-layer capping’). Results from an experiment with thin-layer capping using different active materials (activated carbon (AC) and kraft lignin) showed that both the sediment-to-water flux and the bioaccumulation by benthic species of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), hexachlorobenzene (HCB) and octachlorostyrene (OCS) decreased with increased thick­ness of the cap layer (0.5-5 cm). Amendments with active materials further increased the cap efficiency. AC was more efficient than kraft lignin, and a 3 cm cap with 3.3% AC reduced the flux and bioaccumulation with ~90%. The reduction of the sediment-to-water flux was inversely related to the hydrophobicity of the POP, and reductions in the flux had similar magnitudes as reductions in the concentration in deep-burrowing polychaetes, demonstrating the importance of bioturbation for sediment-to-water transport. In a one-year study on the levels of PCDD/Fs, PCBs, and HCB in a coastal area of the Baltic Sea, the correlations between the POP levels and the levels of particles and organic carbon in the water were found to differ for POPs of different structure and hydrophobicity. The levels of PCDD/Fs decreased to one third in May, which could be related to the increased sedimentation, i.e. water-to-sediment transport, during spring bloom.

Les ignifuges sont ajoutés à divers produits afin de les rendre conformes aux normes d’inflammabilité. Les plus communs sont les polybromodiphényléthers (PBDE) et les esters d’organophosphorés (OPE), qui sont détectés en forte proportion dans la population générale. Quelques industries, comme celle du recyclage électronique, peuvent exposer les travailleurs à des niveaux élevés de ces ignifuges, dont certains sont soupçonnés d’être des perturbateurs endocriniens. L’objectif de cette thèse était d’évaluer l’exposition à des ignifuges chez les travailleurs et d’étudier les effets endocriniens associés. Trois types de données ont été utilisés. D’abord, deux bases de données populationnelles ont permis de déterminer les valeurs biologiques de base des PBDE chez les travailleurs des populations générales canadienne et états-unienne, et d’identifier les secteurs industriels les plus exposés. Ensuite, une revue systématique de littérature a recensé les niveaux d’exposition professionnelle aux ignifuges dans diverses industries en portant un regard critique sur les méthodes de prélèvement. Finalement, des prélèvements d’air en poste personnel, d’urine et de sang ont été réalisés auprès de 100 travailleurs dans six entreprises de recyclage électronique et une de recyclage commercial. Des modèles Tobit et des régressions de Cox inversées ont identifié les tâches les plus exposantes. L’association entre les mesures biologiques d’exposition et les niveaux d’hormones thyroïdiennes et sexuelles a été explorée avec des modèles Tobit et des régressions sur composantes principales. L’analyse des données populationnelles a révélé que les travailleurs canadiens, tous secteurs confondus, avaient des concentrations sériques de PBDE 10 à 20% plus élevées que celles des non-travailleurs. La revue systématique a identifié les milieux du recyclage électronique, de la fabrication de câbles, du transport aérien et des casernes d’incendie comme étant parmi les plus exposants aux ignifuges, particulièrement au BDE209. Cependant, les méthodes de prélèvement utilisées dans ces études étaient généralement peu appropriées pour les ignifuges. L’analyse des données de l’étude terrain a mis en évidence des concentrations d’ignifuges dans l’air plus élevées dans le recyclage électronique que dans le recyclage commercial, avec une concentration en BDE209 plus élevée que toutes les valeurs publiées à ce jour (moyenne géométrique [MG] : 5100 ng/m³). Les tâches de démantèlement et de compactage étaient respectivement associées à des expositions en moyenne 2,2 et 1,4 fois plus élevées que celle de supervision. Finalement, les concentrations sanguines de BDE209 (MG : 18 ng/g lipides) chez les travailleurs du recyclage électronique étaient plus élevées que dans le recyclage commercial (MG : 1,7 ng/g lipides), mais moins élevées que celles rapportées dans la fabrication de câbles (moyenne : 54 ng/g lipides). On a estimé chez l’homme des diminutions de 18% de la testostérone libre et totale pour un doublement de la concentration de tb-TPhP (métabolite OPE), et une augmentation de 16% de l’estradiol pour un doublement de la concentration de o-iPr-DPhP (métabolite OPE). Cette thèse montre que l’exposition aux ignifuges est très répandue, particulièrement chez les travailleurs de quelques industries. Les concentrations plus élevées de certains ignifuges dans le recyclage électronique par rapport aux autres industries, et l’association entre l’exposition aux OPE et les niveaux d’hormones sexuelles chez l’homme ont été identifiées pour la première fois. Bien que devant être reproduits, ces résultats justifient des efforts préventifs de maîtrise de l’exposition aux ignifuges dans cette industrie. / Flame retardants are added to various products to comply to flammability standards. The most common are polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs), which are detected in high proportion in the general population. A few industries, such as electronic recycling, can expose workers to high levels of flame retardants, some of which are suspected of being endocrine disruptors. The objective of this thesis was to evaluate the exposure to flame retardants in workers and to study the associated endocrine effects. Three types of data were used. First, two population databases were used to determine baseline PBDE levels for workers in the general population in Canada and the United States, and to identify the major industrial sectors that are exposed the most. Then, a systematic literature review identified levels of occupational exposure to flame retardants in various industries while critically examining sampling methods. Finally, personal air, urine and blood samples were collected from 100 workers in six electronic recycling and one commercial recycling companies. Tobit models and reverse Cox regressions identified the most exposing tasks. The association between biological concentrations of flame retardants and thyroid and sex hormone levels was explored with Tobit models and principal component regressions. The analysis of the population data revealed that Canadian workers, taking all sectors into consideration, had serum PBDE levels 10 to 20% higher than those of non-workers. The systematic review identified electronic recycling, cable manufacturing, air transport and fire stations as some of the workplaces where flame retardants were found in the highest concentrations, particularly BDE209. However, the sampling methods used in these studies were generally not optimal for flame retardants. Analysis of the field study data revealed higher air concentrations of flame retardants in electronic recycling than in commercial recycling, with a higher BDE209 concentration than all values published to date (geometric mean [MG]: 5100 ng/m³). Dismantling and bailing tasks were associated with exposures averaging 2.2 and 1.4 times higher than supervisory tasks, respectively. Finally, blood concentrations of BDE209 (MG: 18 ng/g lipid) in electronic recycling workers were higher than in commercial recycling (MG: 1.7 ng/g lipid), but lower than those reported in cable manufacturing (average: 54 ng/g lipid). Decreases of 18% in free and total testosterone were estimated in humans for a doubling of the concentration of tb-TPhP (OPE metabolite), and a 16% increase in estradiol for a doubling of the concentration of o-iPr-DPhP (OPE metabolite). This thesis shows that exposure to flame retardants is widespread, particularly among workers in a few industries. The higher concentrations of some flame retardants in electronic recycling compared with other industries, and the association between exposure to OPEs and sex hormone levels in humans were identified for the first time. Although these results must be reproduced, they justify preventive efforts to control exposure to flame retardants in this industry.