Farmed Southern Bluefin Tuna (SBT) (Thunnus maccoyii) is an important export product for South Australia (SA). It is exported to Japan, China, Korea and the United States for the sushi and sashimi markets. The primary purpose of SBT farming in SA is to fatten wild-caught juvenile fish (2-4 years of age with initial mean weights between 12-20 kg) over a period of approximately five months by feeding a selection of baitfish types. Farmers, farm managers and consumers of SBT all have an interest in managing chemical residues that have the potential to biomagnify in the fatty tissue of the farmed SBT fillets. Of particular interest are chemical residues of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins / dibenzofurans (PCDD/Fs). This research presents the investigations and experimental validation of a predictive model that can be used to address the levels of residues in the fillets of farmed SBT at harvest from feeding (as the source) when applied to SBT aquaculture. An additional industry-focussed aim of this research was to determine if a Longer Term Holding (LTH) farming period, with a duration of an extra 12 months after a typical farming period of approximately five months, could produce SBT with higher condition index (CI) and lipid content, while keeping levels of PCBs and PCDD/Fs low, compared to the typical farming period. The justification for this research is that an adequate quantitative model is essential to help industry achieve targeted concentrations in the final fillet product by making scientific-based decisions on baitfish selection (baitfish strategies for the feeding of SBT), and longer term, to confidently demonstrate to local markets and importing countries that Australia is actively managing levels of PCBs and PCDD/Fs in farmed SBT, to ensure a high quality and safe product is delivered to the consumer. The novelty of this research is underpinned by four integrated stages, and the criteria for an adequate model established. The important criteria included: accurate predictions versus observed data demonstrated through the analysis of residual plots, potential physiological interpretation of model coefficients, parsimony – the model should be as simple as possible (but no simpler) and that the model should be easy to use. Firstly, a logical starting point was the development of a risk framework for residues in SBT. The developed framework was based on conventional principles of microbiological risk assessment highlighted in Codex Alimentarius. The risk framework consists of five governing principles: hazard identification, hazard characterisation, exposure assessment, risk characterisation and model validation. The advantages of the risk framework is that it provides a systematic research approach and permits information to be handled unambiguously, especially important for the niche SBT industry where chemical residue research is carried out for the first time. Secondly, because of a lack of available scientific data in context of this research, commercial-scale experimental field data for levels of PCBs and PCDD/Fs in typical farmed SBT as affected by feeding and growth were collected over 17 months at seven time intervals from Farm Delta Fishing Pty Ltd in 2005/06 (n = 50). Field data from another commercial company, Farm Alpha Fishing Pty Ltd, was collected over the typical farming period specific to this company, spanning 15 weeks at three time intervals in 2006, for validation work (n = 15). The data obtained from Farm Delta Fishing Pty Ltd revealed that whole weight of farmed SBT increased from 18.5 kg to 30.3 kg for a typical farming period, and subsequently to 41.0 kg by the end of the LTH farming period. A maximum mean CI of 24.0 ± 0.5 kg.m⁻³ and a maximum mean lipid content of 17.6 ± 0.5% was achieved at the third time interval of the typical farming period, for the baitfish types and ratios used as feed. There were no significant differences in the CI and lipid between the final harvests of the typical farming and LTH periods, i.e. even after an additional 12 months of farming. PCB and PCDD/F concentrations, however, increased between the final harvests of the typical farming and LTH periods. The data indicated that a typical farming period was sufficient to achieve a maximum CI and lipid content with lower concentrations of PCBs and PCDD/Fs in the fillets relative to the LTH farming period. For the third stage of this research, a quantitative model was synthesised and applied to the PCB and PCDD/F (2,3,7,8-TeCDF) data detected in farmed SBT fillets. Assimilation efficiencies for PCBs and 2,3,7,8-TeCDF in the fillets of SBT were obtained. An assimilation efficiency, or percentage retention (efficiency expressed as a percentage), in the fillet of SBT is a measure of the uptake of a chemical residue from food (baitfish) to the SBT fillet. For the WHO-PCBs, assimilation efficiencies based on SBT fillets ranged between 19.1 – 35.3 % with the exception of PCB 169. The highest assimilation efficiency of 35.3 %, with a range of 30.4 – 40.3 % (at the 95 % confidence level) was attributed to the most toxic PCB congener, PCB 126. An assimilation efficiency of 39.2 % was determined in SBT fillets for the congener 2,3,7,8-TeCDF, which was higher than the assimilation efficiencies determined for the WHO-PCB congeners. A residual plot as predicted value versus observed value indicated that the predictive model was neither under- or over-parameterised. However, when the predictive model was assessed against the data set from Farm Alpha Pty Ltd, the model over-predicted the actual PCB and PCDD/F concentrations. The over-prediction is attributed to possible overfeeding of SBT farmed by Farm Alpha Fishing Pty Ltd. From a food safety point of view, in the absence of ideal predictions because of a lack of ideal validation data sets, an over-prediction instead of under-prediction is preferred. In the fourth stage, the practical application of the predictive model was demonstrated. Because SBT fillets are retailed as tissue group-specific, i.e. akami (low fat), chu-toro (medium fat) and otoro (high fat) fillets, PCB and PCDD/F analyses were carried out on the three tissue groups for selected SBT (n = 7). Dietary modelling on SBT consumption in humans was carried out using findings from the predictive model and tissue-specific data. The baitfish strategy employed for the feeding of farmed SBT consequently affects dietary exposure to SBT consumers. Exposure to PCBs and PCDD/Fs is approximately seven times lower for the consumption of a skin-free, boneless akami fillet than for a comparable otoro fillet of the same size. This dietary exposure assessment accounted only for consumption of SBT tissue-specific fillets. The experimental field study and modelling work on PCB and PCDD/F concentrations in farmed SBT (fillets) outlined in this thesis importantly directs the need to re-evaluate a specific model to better cater for SBT farming practices where SBT fillets are produced for human consumption. Because conditions that normally pertain to commercial farming of wild-caught fish were studied, findings should be of interest to industries where other species of fish (for food) are farmed in sea-cages in the open ocean. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342453 / Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 2008

Farmed Southern Bluefin Tuna (SBT) (Thunnus maccoyii) is an important export product for South Australia (SA). It is exported to Japan, China, Korea and the United States for the sushi and sashimi markets. The primary purpose of SBT farming in SA is to fatten wild-caught juvenile fish (2-4 years of age with initial mean weights between 12-20 kg) over a period of approximately five months by feeding a selection of baitfish types. Farmers, farm managers and consumers of SBT all have an interest in managing chemical residues that have the potential to biomagnify in the fatty tissue of the farmed SBT fillets. Of particular interest are chemical residues of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins / dibenzofurans (PCDD/Fs). This research presents the investigations and experimental validation of a predictive model that can be used to address the levels of residues in the fillets of farmed SBT at harvest from feeding (as the source) when applied to SBT aquaculture. An additional industry-focussed aim of this research was to determine if a Longer Term Holding (LTH) farming period, with a duration of an extra 12 months after a typical farming period of approximately five months, could produce SBT with higher condition index (CI) and lipid content, while keeping levels of PCBs and PCDD/Fs low, compared to the typical farming period. The justification for this research is that an adequate quantitative model is essential to help industry achieve targeted concentrations in the final fillet product by making scientific-based decisions on baitfish selection (baitfish strategies for the feeding of SBT), and longer term, to confidently demonstrate to local markets and importing countries that Australia is actively managing levels of PCBs and PCDD/Fs in farmed SBT, to ensure a high quality and safe product is delivered to the consumer. The novelty of this research is underpinned by four integrated stages, and the criteria for an adequate model established. The important criteria included: accurate predictions versus observed data demonstrated through the analysis of residual plots, potential physiological interpretation of model coefficients, parsimony – the model should be as simple as possible (but no simpler) and that the model should be easy to use. Firstly, a logical starting point was the development of a risk framework for residues in SBT. The developed framework was based on conventional principles of microbiological risk assessment highlighted in Codex Alimentarius. The risk framework consists of five governing principles: hazard identification, hazard characterisation, exposure assessment, risk characterisation and model validation. The advantages of the risk framework is that it provides a systematic research approach and permits information to be handled unambiguously, especially important for the niche SBT industry where chemical residue research is carried out for the first time. Secondly, because of a lack of available scientific data in context of this research, commercial-scale experimental field data for levels of PCBs and PCDD/Fs in typical farmed SBT as affected by feeding and growth were collected over 17 months at seven time intervals from Farm Delta Fishing Pty Ltd in 2005/06 (n = 50). Field data from another commercial company, Farm Alpha Fishing Pty Ltd, was collected over the typical farming period specific to this company, spanning 15 weeks at three time intervals in 2006, for validation work (n = 15). The data obtained from Farm Delta Fishing Pty Ltd revealed that whole weight of farmed SBT increased from 18.5 kg to 30.3 kg for a typical farming period, and subsequently to 41.0 kg by the end of the LTH farming period. A maximum mean CI of 24.0 ± 0.5 kg.m⁻³ and a maximum mean lipid content of 17.6 ± 0.5% was achieved at the third time interval of the typical farming period, for the baitfish types and ratios used as feed. There were no significant differences in the CI and lipid between the final harvests of the typical farming and LTH periods, i.e. even after an additional 12 months of farming. PCB and PCDD/F concentrations, however, increased between the final harvests of the typical farming and LTH periods. The data indicated that a typical farming period was sufficient to achieve a maximum CI and lipid content with lower concentrations of PCBs and PCDD/Fs in the fillets relative to the LTH farming period. For the third stage of this research, a quantitative model was synthesised and applied to the PCB and PCDD/F (2,3,7,8-TeCDF) data detected in farmed SBT fillets. Assimilation efficiencies for PCBs and 2,3,7,8-TeCDF in the fillets of SBT were obtained. An assimilation efficiency, or percentage retention (efficiency expressed as a percentage), in the fillet of SBT is a measure of the uptake of a chemical residue from food (baitfish) to the SBT fillet. For the WHO-PCBs, assimilation efficiencies based on SBT fillets ranged between 19.1 – 35.3 % with the exception of PCB 169. The highest assimilation efficiency of 35.3 %, with a range of 30.4 – 40.3 % (at the 95 % confidence level) was attributed to the most toxic PCB congener, PCB 126. An assimilation efficiency of 39.2 % was determined in SBT fillets for the congener 2,3,7,8-TeCDF, which was higher than the assimilation efficiencies determined for the WHO-PCB congeners. A residual plot as predicted value versus observed value indicated that the predictive model was neither under- or over-parameterised. However, when the predictive model was assessed against the data set from Farm Alpha Pty Ltd, the model over-predicted the actual PCB and PCDD/F concentrations. The over-prediction is attributed to possible overfeeding of SBT farmed by Farm Alpha Fishing Pty Ltd. From a food safety point of view, in the absence of ideal predictions because of a lack of ideal validation data sets, an over-prediction instead of under-prediction is preferred. In the fourth stage, the practical application of the predictive model was demonstrated. Because SBT fillets are retailed as tissue group-specific, i.e. akami (low fat), chu-toro (medium fat) and otoro (high fat) fillets, PCB and PCDD/F analyses were carried out on the three tissue groups for selected SBT (n = 7). Dietary modelling on SBT consumption in humans was carried out using findings from the predictive model and tissue-specific data. The baitfish strategy employed for the feeding of farmed SBT consequently affects dietary exposure to SBT consumers. Exposure to PCBs and PCDD/Fs is approximately seven times lower for the consumption of a skin-free, boneless akami fillet than for a comparable otoro fillet of the same size. This dietary exposure assessment accounted only for consumption of SBT tissue-specific fillets. The experimental field study and modelling work on PCB and PCDD/F concentrations in farmed SBT (fillets) outlined in this thesis importantly directs the need to re-evaluate a specific model to better cater for SBT farming practices where SBT fillets are produced for human consumption. Because conditions that normally pertain to commercial farming of wild-caught fish were studied, findings should be of interest to industries where other species of fish (for food) are farmed in sea-cages in the open ocean. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342453 / Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 2008

The recent developments and improvements of instrumental methods for the analyses of the environmental contaminants, especially the persistent organic pollutants (POPs), have made it possible to detect and quantify these at very low concentrations in environmental and biotic matrices. The main objective of this thesis is to demonstrate the capability of the atmospheric pressure chemical ionization technique (APCI), using gas chromatography coupled to tandem mass spectrometry for the determination of a wide range of environmental contaminants, including the POPs regulated by Stockholm Convention, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), but also the derivates of PBDEs and novel brominated flame retardants (NBFRs). The APCI was operated in charge transfer condition, preferably producing molecular ions. Multiple reaction monitoring (MRM) experiments were optimized by adjusting cone voltage, collision energy and dwell time. Optimization of source parameters, such as gas flows and temperatures was also performed. Low concentration standards were analyzed, achieving a visible chromatographic peak for 2 fg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) demonstrating the excellent sensitivity of the system. Adequate linearity and repeatability were observed for all the studied compounds. The performance of APCI methods was validated against the conventional methods using gas chromatography coupled to high resolution mass spectrometry for chlorinated compounds in a wide range of matrices including environmental, air, human and food matrices. The GC-APCI-MS/MS method was successfully applied to a set of 75 human serum samples to study the circulating levels of POPs in epidemiologic studies. Moreover the method was utilized to establish temporal trends of POPs in osprey eggs samples collected during the past five decades.

La contamination des sols et sédiments par les polychlorobiphényls (PCB) pose un problème sanitaire et environnemental à l’échelle mondiale, en raison de la récalcitrance et de la toxicité de ces composés. L’objectif de cette thèse est de chercher un procédé de remédiation de sédiments contaminés aux PCB en utilisant le fer zérovalent (Fe0). D’abord, une campagne de prélèvement a été menée sur des sites contaminés par le recyclage des déchets électroniques en Chine du sud. La contamination en PCB n’était pas aussi forte que prévue, mais la présence de métaux lourds accentue la difficulté de la remédiation. Ensuite, a été étudiée la déchloration des PCB par le Fe0 en solution aqueuse, en présence de métaux et surfactants. Les résultats ont montré la déchloration progressive des PCB et révélé l’itinéraire réactionnel avec la spécificité des congénères et la régio-spécificité. L’importance relative des facteurs qui influent se classe selon : tensioactif > acide humique > pH > Ni2. La décontamination du sédiment a été étudiée par 1) lavage avec une solution aqueuse de tensioactif suivie de la déchloration des PCB en solution et 2) mélange direct avec le Fe0 et les tensioactifs. La seconde approche s’est avérée prometteuse pour la remédiation / Soil and sediment contamination by polychlorinated biphenyls (PCBs) is a global health and environmental concern, since PCBs are toxic and recalcitrant. The aim of this thesis is to find a remediation process to PCBs contaminated sediments by using zerovalent iron (ZVI). To begin the studies on remediation, a survey was conducted on sites contaminated by e-waste recycling activities in south China. PCBs contamination was not as severe as previously, whereas the co-existence of PCBs and heavy metals increases the difficulty of remediation. Afterwards, the feasibility PCBs degradation by ZVI in aqueous solutions was investigated. Results confirmed the stepwise dechlorination of PCBs by ZVI and the major pathway with congener specifity and regiospecifity. The relative importance of the influential factors to ZVI degradation of PCBs was in the order of surfactants > humic acid > pH > Ni2+. Sediment decontamination was studied by 1) washing with an aqueous solution of surfactant followed by ZVI dechlorination of PCBs and 2) direct mixing with ZVI and surfactant solution. The second approach gave promising results for remediation

The master’s thesis was focused on the determination of persistent organic pollutants, namely polychlorinated biphenyls were detected (PCB 28, 52, 101, 118, 138, 153 and 180) and organochlorine pesticides. A total of 31 were evaluated contamination of organochlorine compounds. The level of contamination by organic pollutants were detected in 20 samples, 9 samples were sediments from the river Jevišovka, which is located in the South Moravia and 11 samples represented arable soil samples and were collected in the vicinity of this river. In the theoretical part are characterized both groups of substances, their fate in the environment and negative effects on living organisms. The experimental part focuses on the sampling procedures and processing for analysis by gas chromatography. There is described a complex analytical process involving the three extraction methods (accelerated solvent extraction, microwave extraction and ultrasonic extraction), extract purification and self-determination by gas chromatography with electron capture detector (GC / ECD). In the samples of sediment were detected these PCB congeners (138, 153 and 180) and organochlorine pesticides (b-HCH, HCB, p,p’-DDE, p,p’-DDD, p,p’-DDT and o,p’-DDT).. In soil samples were detected PCB congener 28 and organochlorine pesticides (HCB, b-HCH, heptachlor, aldrin, dieldrin, p,p’-DDE, p,p’-DDD, p,p’-DDT and o,p’-DDT).

Byla provedena studie bioakumulace POP v potravním řetězci a historických trendů hladin POP v sedimentech Brněnské přehrady. Současné úrovně kontaminantů byly stanoveny v jelci tloušti z řeky Svratky a rovněž byla posouzena hygienická kvalita ryb z rekreačního rybolovu. Současné úrovně POP v terestrickém ekosystému byly posouzeny pomocí analýz jehličí jako přirozeného indikátoru znečištění. Studium jedinců tří druhů dravých ptáků z ČR bylo zaměřeno na zhodnocení kontaminace těchto vrcholných predátorů POP. S pomocí analýz vybraných druhů ryb ze Záhlinických rybníků byl rovněž studován proces bioakumulace. Posouzení parametrů dvou moderních extrakčních technik a jejich využitelnosti pro izolaci POP z různých matric bylo námětem poslední části dizertace.

Die Akkumulation von lipophilen und biologisch persistenten Chlorkohlenwasserstoffen in der Nahrungskette und die infolgedessen auftretende relativ hohe Belastung gestillter Säuglinge hat zu Besorgnissen hinsichtlich möglicher negativer Folgen für die Gesundheit dieser Kinder geführt. Ein Fokus der Arbeit ist Frage, ob der Kontamination von Humanmilch mit polychlorierten Dibenzo-p-dioxinen (PCDDs, 'Dioxine'), Dibenzofuranen (PCDFs, 'Furanen') und Biphenylen (PCBs) in Deutschland zu messbaren Veränderungen sensibler biologischer Parametern führt. Blut wurde im Alter von 11 Monaten von gestillten (für mindestens 4 Monate, n=80) und nicht gestillten Kindern (n=21) entnommen zur umfangreichen Untersuchung des Immunsystems, von biologischen Parametern im Plasma und von Parametern der Schilddrüsenfunktion. Die direkte Messung von PCDDs, PCDFs und PCBs im Plasma bei den Kindern und deren Müttern konnte die erwartete Akkumulation dieser Verbindungen bestätigen, die etwa 4-fach höheren Werten beim Kind (im Vergleich zu mütterlichen Werten) nach einer langen Stillperiode vom 40 Wochen entspricht. Es konnte keine signifikante Korrelation von den untersuchten biologischen Parametern mit den Fremdstoff-Konzentrationen gefunden werden. Somit konnten keine biologischen Effekte dieser in der Muttermilch ungewünschten Verbindungen nachgewiesen werden, und die bestehende Stillempfehlung konnte bekräftigt werden. Der zweite Fokus der Arbeit beschäftigt sich mit der Frage von biologischen Wirkungen bei zwei Frauen, die gegenüber der am meisten toxischen Dioxin-Verbindung exponiert wurden: 2,3,7,8-Tetrachlordibenzo-p-dioxin (TCDD). Diese Frauen hatten die höchsten je beim Menschen gemessenen Konzentrationen, eine der beiden leidet unter einer schweren Chlorakne. Es wurde ein breites Spektrum immunologischer Parameter untersucht sowie die Aktivität der Cytochrome P450 1A2 (CYP1A2) Aktivität in der Leber, die mit dem Koffein-Test gemessen wurde. Zum Vergleich wurden zwei Kontrollgruppen bestehend aus 30 Nichtrauchern bzw. 20 starken Rauchern untersucht unter Verwendung der gleichen Methoden. Die Ergebnisse des Koffein-Tests zeigen eine ca. 10-fach höhere CYP1A2-Aktivität bei den hoch TCDD-exponierten Frauen, während Tabakrauch (durchschnittlich 28 Zigaretten pro Tag) zu einem maximal 1,8-fachem Anstieg führte. Die immunologischen Untersuchungen zeigten keine Hinweise auf einen starken Einfluss von TCDD bei den hochexponierten Frauen. Es bestätigte sich, dass der Mensch relativ wenig sensibel ist in Hinblick auf die toxischen Effekte von TCDD. / The accumulation of lipophilic and biologically persistent chlorinated hydrocarbons in the food chain and the following relatively high exposure of breast-fed infants has caused concern about possible negative health effects in these children. One focus of the document is the question whether the contamination of human milk with polychlorinated dibenzo-p-dioxins (PCDDs, 'dioxins'), dibenzofurans (PCDFs, 'furans') and biphenyls (PCBs) in Germany leads to measurable changes of sensitive biological parameters. Blood was taken from breast-fed (for at least four months, n=80) and formula-fed infants (n=21) at the age of 11 months for extensive investigations regarding the immune system and biological parameters in plasma including those of the thyroid function. From direct measurements of PCDDs, PCDFs and PCBs in plasma of the children and their mothers, the expected accumulation of the compounds was confirmed, corresponding to about 4-times higher values in the infant (compared to maternal values) following a long duration of breast-feeding of 40 weeks. For the different biological parameters investigated, no significant correlation with concentrations of the xenobiotics was found. Therefore, biological effects of these unwanted compounds in human milk. could not be detected, and the existing recommendation for breast-feeding was emphasized. The second focus of the document is the investigation of biological changes in two women exposed to the most toxic dioxin: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). These women had the highest concentrations of this compound ever measured in adults, one of them suffering from severe chloracne. A broad panel of immunological parameters was measured as well as hepatic cytochrome P450 1A2 (CYP1A2) activity using the caffeine test. For comparison, two age-matched control groups of 30 non-smokers and 20 heavy smokers were studied using the same methods. Results of caffeine tests showed an about 10-fold increase of CYP1A2 activity in the highly TCDD-exposed women, whereas tobacco smoke (28 cigarettes per day on average) was found to increase the activity 1.8-times maximally. Immunological investigations did not reveal a strong impact of TCDD in these highly exposed women. These results confirm that humans are relatively insensitive to the toxic effects of dioxins.

Dans un contexte où les inquiétudes environnementales dues à la pollution sont grandissantes à l’échelle globale, la surveillance de la pollution environnementale constitue un enjeu majeur de recherche afin de préserver au mieux un environnement sain et durable. En effet, la surveillance responsable et continue de l’environnement accompagnée par le développement d’alternatives de lutte « verte » contre les nuisibles, pourrait certainement ralentir voir inhiber la propagation de polluants néfastes pour l’ensemble de la biosphère. Dans ce contexte, les objectifs principaux de cette thèse visent d’une part à caractériser la qualité de l’air par une approche basée sur le biomonitoring, et d’autre part à développer un biopesticide d’origine algale permettant la protection des agrumes en post-récolte comme un exemple d’alternative à l’usage des traitements chimiques classiques. Pour répondre au premier objectif, des méthodes d’extraction multi résidus ont dû être développées. Ces méthodes ont été soit spécifiques d’une famille de pesticides tel que les dithiocarbamates, soit plus large et plus générale en considérant de nombreux polluants comme des pesticides, des HAPs et des PCBs. Ces dernières ont été basées soit sur l’ASE-SPE-SPME, soit sur le QuEChERS-SPME, et ont formé le socle des études de biosurveillance environnementale entreprises. Ces études de surveillance ont permis l’évaluation des modifications spatio-temporelles de la qualité de l’air grâce à des espèces naturelles ayant un rôle de capteurs biologique de la pollution environnementale et permettant par la suite l’estimation de la pollution dans des zones bien définies. Pour répondre au second objectif, des extraits aqueux d’algues vertes, Ulva linza et Ulva lactuca, ont été préparés et testés comme antifongiques in vivo et in vitro afin d’étudier leur aptitude à inhiber le développement de Penicillium digitatum sur des agrumes en post récolte. Un potentiel de protection des agrumes en poste-récolte contre ce champignon a été mis en évidence, donnant effectivement l’espoir à la fiabilité de cette approche comme alternative biologique pour le remplacement des pesticides chimiques potentiellement toxiques. / In a context where environmental concerns due to pollution are growing on a global scale, monitoring of environmental pollution is a major research challenge in order to preserve as much as possible a healthy and sustainable environment. Indeed, the responsible and continuous monitoring of the environment escorted by the development of "green" pest control alternatives could certainly decelerate or even inhibit the spread of harmful pollutants into the entire biosphere. In this context, the main objectives of this thesis are intended firstly to characterize air quality by a biomonitoring-based approach and, secondly, to develop a biopesticide of algal origin, that allows the protection of post-harvested citrus fruit, as an alternative to the use of conventional chemical treatments. In order to answer the first objective, multi-residues extraction methods were developed. These methods were either specific to a family of pesticides such as dithiocarbamates or wider and more general regarding numerous pollutants such as pesticides, PAHs and PCBs. The latter were based either on the ASE-SPE-SPME, or on the QuEChERS-SPME, and formed the base of environmental biomonitoring studies undertaken. These monitoring studies allowed the assessment of spatial and temporal changes in air quality through natural species acting as biological sensors of environmental pollution and subsequently allowing the estimation of pollution in well-defined areas. To answer the second objective aqueous extracts of green algae, Ulva linza and Ulva lactuca, were prepared and tested as in vivo and in vitro antifungal agents, in order to study their ability to inhibit the development of Penicillium digitatum on post-harvested citrus fruits. A potential of post-harvested citrus fruits’ protection against this fungus was proved, giving hope to the reliability of this approach as a biological alternative for the replacement of potentially toxic chemical pesticides.

Les estuaires sont des écosystèmes aquatiques particulièrement soumis au changement global et notamment à la pollution par de nombreux xénobiotiques pouvant présenter un risque écotoxicologique et sanitaire. En toxicologie environnementale et en évaluation des risques la bioaccumulation est un processus fondamental car elle contrôle les doses internes de toxiques potentiels. Or les flux de contamination et de décontamination des organismes dépendent de processus internes (e.g. nutrition, croissance) eux-mêmes dépendant des conditions environnementales (e.g. température, nourriture) qui peuvent être affectées par le changement global.Dans ce contexte, cette thèse se propose de décrire, dans un cadre de modélisation mécaniste, les processus de bioaccumulation de deux familles de polluants organiques persistants (POP) halogénés potentiellement toxiques et bioaccumulables, aux propriétés physico-chimiques contrastées : les polychlorobiphényles (PCB, composés historiques fortement lipophiles) et les substances perfluorées (PFAS, composés émergents amphiphiles). Ce travail se focalise sur l’estuaire de la Gironde dont la fonction de nourricerie est fondamentale pour de nombreuses espèces de poissons marins dont la sole commune (Solea solea), souvent utilisée comme indicatrice de la qualité des nourriceries côtières et estuariennes.Pour permettre de tenir compte des fluctuations des conditions environnementales sur la bioaccumulation, dans la première partie de ce travail, j’ai développé un modèle de toxicocinétique(TK) couplé avec un modèle mécaniste bioénergétique basé sur la théorie DEB (Dynamic Energy Budget). Ce modèle DEB a été paramétré pour la sole commune et calibré pour chaque sexe (package DEB tool). Il permet de prédire les principales évolutions des fonctions physiologiques d’intérêt en bioaccumulation (ingestion, croissance, reproduction...), tout au long du cycle de vie d’un individu, en fonction de conditions environnementales dynamiques. Le modèle TK développé a été complexifié par l’ajout d’un flux d’élimination de contaminants, non considéré dans les précédents modèles DEB-TK.La calibration des paramètres toxicocinétiques (TK) du modèle, pour 4 congénères de PCB, est basée sur une méthode innovante de prise en compte de la variabilité individuelle d’ingestion, appliquée à une expérimentation de contamination de juvéniles de sole via leur nourriture. Ce travail a montré que même en tenant compte de l’ingestion de chaque poisson, l’assimilation efficace de contaminant était très variable et corrélée aux taux de lipides des individus. Dans une seconde partie, ce modèle a été appliqué aux conditions in situ de l’estuaire de la Gironde. Il a permis de mettre en évidence la forte influence de la composition du régime alimentaire sur la variabilité de l’âge à la maturité sexuelle et de la contamination des soles pour les deux familles de contaminant étudiées. La confrontation des prédictions du modèle aux mesures de contaminants dans les juvéniles de sole de l’estuaire a permis de calibrer les paramètres TK du composé majeur de chaque famille dans l’environnement (CB153 et PFOS). Cette calibration a conduit à deux constats dans le cadre de l’évaluation du risque : (1) un manque de connaissances pour extrapoler les calibrations de paramètres TK en conditions contrôlées vers les conditions naturelles ; (2) la différence d’erreur d’évaluation du risque liée à l’utilisation des mêmes paramètres TK «les plus pessimistes » quels que soient les composés. Enfin, des scenarios prospectifs simples ont été développés pour illustrer ces résultats et les possibles applications du modèle développé.In fine, ces prédictions de la contamination, de la croissance et du développement des soles pourront être reliées, lors de travaux ultérieurs, à des effets potentiels sur les fonctions physiologiques de la sole (modèles DEBtox), et aux conséquences sur la dynamique des populations de soles (e.g.modèles matriciels de population). / Estuarine ecosystems are particularly impacted by global change and, specifically, bychemical pollution from numerous xenobiotics that may be associated to ecotoxicological and health risks. In environmental toxicology and risk assessment, bioaccumulation is a fundamental process as it controls the internal doses of potential toxicants in organisms. However, the contamination and decontamination flows depend on internal processes thatare themselves dependent on environmental conditions (e.g. temperature, food) and thus on the other variables of global change.In this context, this manuscript aims at describing, within a mechanistic modelling framework, the bioaccumulation processes of two families of potentially toxic and bioaccumulable halogenated persistent organic pollutants (POPs) with contrasting physicochemical properties: the polychlorinated biphenyls (PCBs, highly lipophilic historical compounds) and the perfluorinated substances (PFAS, amphiphilic emerging compounds).This work focuses on the Gironde estuary whose nursery function is fundamental for many species of marine fish including the common sole (Solea solea), often used as an indicator of the quality of coastal and estuarine bursary grounds. In order to account for the influence of environmental conditions on bioaccumulation, the first part of this work consisted in developing a toxicokinetic model (TK) coupled with a mechanistic bioenergetic model based on the theory DEB (Dynamic Energy Budget). This DEBmodel has been parameterized for common sole and calibrated for each sex (packageDEBtool). It allows predicting the main evolution of the physiological functions of interest forbioaccumulation (ingestion, growth, reproduction...) throughout the life cycle of an individualaccounting for dynamic environmental conditions. The developed TK model was first calibrated for some PCBs, under controlled conditions, using an innovative method to take into account individual ingestion variability. This work showed that even if the individual ingestion of each fish is accounted for, the effective assimilation of contaminant is very variable and correlated with the lipid levels of the individuals. The application of the model tothe in situ conditions of the Gironde estuary led to identify that, whatever the contaminant family, the composition of the soles diet had a strong influence on the variability of soles contamination and age at sexual maturity. The comparison of model predictions with measurements made in juveniles of the estuary allowed calibrating the TK parameters values for the major compound of each family in the environment (CB153 and PFOS). This calibration led to two observations in the context of a risk assessment: (1) a lack of knowledge to extrapolate calibrations of TK parameters under controlled conditions to natural conditions;(2) the difference in risk assessment error related to the use of the same "worst case" TK parameters regardless of the compounds. Lastly, simple prospective scenarios have beendeveloped to illustrate these results and the possible applications of the model developed.Ultimately, these predictions of soles contamination, growth and development may be related in future work to potential effects on the physiological functions of sole (DEBtox models), and to consequences on soles population dynamics (e.g. matrix population models).

The efficiency of wastewater treatment systems is commonly measured by the reductions of parameters such as biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) and/or reductions in levels of selected macro compounds (e.g. long-chained hydrocarbons and inorganic compounds). Less attention has generally been paid to micropollutants with high potential toxic effects, such as polycyclic aromatic compounds (PACs), including unsubstituted and alkylated polycyclic aromatic hydrocarbons (PAHs) and dibenzothiophenes, polychlorinated biphenyls (PCBs), human pharmaceuticals and by-products formed during the treatment process. These organic micropollutants occur in wastewaters at trace and ultra-trace levels, therefore their detection requires advanced, costly analyses and large sample volumes. Furthermore, concentrations of micropollutants can fluctuate widely both diurnally and between days. Thus, in order to understand the fate of micropollutants in wastewaters there is a need to develop sampling techniques that allow representative samples to be readily collected. In the work underlying this thesis two types of diffusive passive samplers, semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCISs), were used to monitor non-polar and polar organic micropollutants in wastewaters subjected to various treatment processes. The pollutants sequestered in these samplers represent micropollutants in the dissolved phase that are available for aquatic organisms. Further, since they collect pollutants in an integrative manner, i.e. they sample continuously during the selected exposure time (usually approx. one to ca. three weeks), the results provide time-weighted average (TWA) concentrations. In addition, the effects of various environmental factors on the uptake of analyzed micropollutants in POCISs and SPMDs were investigated using laboratory calibration and in situ calibration with performance reference compounds (PRCs). The results confirm that SPMDs are good sampling tools for investigating the efficacy of wastewater treatment processes for removing non-polar PACs and PCBs, and the effects of varying the process settings. In addition, analyses of process streams in municipal sewage treatment plants demonstrated that conventional sewage treatment processes are not optimized for removing dissolved four-ringed PAHs, some of the five-ringed PAHs, and tri- to hexa-chlorinated biphenyls. The removal of bioavailable PACs was enhanced by adding sorbents with high sorption capacities to the sludge used in the activated sludge treatment step, and a biologically activated carbon system was designed that robustly removed bioavailable PACs, with removal efficiencies of 96.9-99.7 percent across the tested ranges of five varied process parameters. In situ SPMD calibration data acquired show that uptake of PACs, described by SPMD sampling rates (Rs), were four to eight times higher than published laboratory calibrated Rs values, mainly due to strong (bio)fouling and turbulence effects. In addition, the laboratory calibration study demonstrated that temperature affects the POCIS uptake of pharmaceuticals. The uptake of four pharmaceuticals was higher, by 10-56 percent, at 18 °C compared to 5 °C. For two of the pharmaceuticals our data indicate that the uptake was lower by 18-25 percent at 18 °C. Our results also indicate that uptake of the studied pharmaceuticals was in the linear phase throughout the 35 day exposure period at both temperatures. Finally, calibration studies enabled aqueous concentrations of micropollutants to be more accurately estimated from amounts collected in the passive samplers.