Dissertations / Theses on the topic 'Persistent organic pollutants'

Abstract Persistent organic pollutants (POPs), especially dioxin-like chemicals, have been shown to have adverse effects on skeleton and these effects are likely to be mediated via the aryl hydrocarbon receptor (AHR). In spite of the extensive research, the characteristics of developmental effects of POPs are poorly known and the role of AHR in POP bone toxicity and skeletal development in general. In this project changes in bone morphology and strength as well as tissue matrix mechanics are studied by applying state of the art biomedical engineering methods. This allows understanding of the effects of dioxins exposure and AHR activity on the development and maturation of extracellular matrix in musculoskeletal tissues from a completely new perspective, and thereby improving the health risk assessment of POPs. In the present study skeletal properties of rats exposed maternally to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), Northern Contaminant Mixture (NCM) and Aroclor1254 (A1254) were studied for cross-sectional morphometric and biomechanical properties, and data were analysed with benchmark dose modelling. In addition, extracellular matrix properties were analysed using nanoindentation. Similar measurements were performed for adult wild-type and AHR-null mice after TCDD exposure. The same animals were also analysed for microstructural changes using micro-computed tomography and their bone cell activity was estimated from serum markers and gene expression. Analyses show decreased bone length and cross-sectional properties with consequently decreased bone strength. On the other hand, an increased trabecular BMD in response to NCM and A1254 was observed. In addition, bone matrix properties indicated delayed maturation or early senescence after maternal or adult exposure, respectively. The AHR is mainly responsible for bone toxicity of dioxin-like compounds and plays a role in bone development. This is likely due to disturbed bone remodeling as indicated by altered serum markers and gene expression. Overall these results indicate that POPs decrease bone strength, but the interpretation is difficult as there is more trabecular bone within cortical bone with compromised quality and increased porosity
Tiivistelmä Altistumisen pysyville orgaanisille ympäristökemikaaleille on todettu heikentävän luustoa. Dioksiinien ja dioksiininkaltaisten yhdisteiden vaikutusten on havaittu välittyvän aryylihiilivetyreseptorin (AHR) välityksellä. Huolimatta pitkään kestäneestä tutkimuksesta POP-yhdisteiden sikiönkehityksen aikaisen altistuksen vaikutukset ja etenkin niiden mekanismit ovat edelleen huonosti tunnettuja, samoin kuin AHR:n osuus POP-yhdisteiden luutoksisuudessa ja luuston kehityksessä ylipäätään. Tässä työssä tutkittiin luuston rakenteellisia ja mekaanisia ominaisuuksia niin perinteisillä kuin uusimmilla biolääketieteen tekniikan menetelmillä. Tutkimuksen tavoitteena on saada uutta tietoa POP-altistuksen ja AHR-aktiivisuuden vaikutuksista luuston kehitykseen ja luukudoksen ikääntymisprosesseihin, mikä edesauttaa kyseisten yhdisteiden riskinarviointia. Tutkimuksissa altistettiin kantavia rottaemoja 2,3,7,8-tetraklooridibenzo-p-dioksiinille (TCDD), pohjoiselle saasteseokselle ja kaupalliselle Arokloori 1254 PCB-seokselle. Sikiönkehityksen aikana altistuneiden jälkeläisten luuston poikkileikkausen morfologia ja biomekaaniset ominaisuudet mitattiin ja tulokset mallinnettiin vertailuannoksen määrittämiseksi. Lisäksi TCDD-altistettujen rottien luustomatriisin ominaisuuksia selvitettiin nanoindentaatiomenetelmällä. Samaa menetelmää käytettiin myös aikuisiässä TCDD:lle altistettujen villityypin hiirten ja AHR-poistogeenisiten hiirten tutkimiseen. Näiden hiirten luuston hienorakennetta mitattiin myös korkean resoluution mikro-tietokonetomografialla ja niiden luusolujen aktiivisuutta tutkittiin seerumin biomarkkerien ja luun muodostumiseen osallistuvien geenien ekspressiotasojen avulla. Sikiönkehityksen aikainen altistuminen pohjoiselle saasteseokselle ja Arokloori 1254:lle hidasti luiden pituuskasvua. Lisäksi luiden poikkileikkauspinta-alat olivat pienentyneet ja mekaaniset ominaisuudet heikentyneet. Toisaalta hohkaluun määrä oli lisääntynyt altistumisen seurauksena. Myös sikiönkehityksen aikainen altistuminen TCDD:lle hidasti luukudoksen kypsymistä ja johti aikuisiällä luukudoksen ennenaikaiseen vanhenemiseen. AHR:llä oli päärooli ainakin aikuisiän vaikutusten ilmenemiselle ja reseptorilla vaikutti olevan rooli luuston kehityksessä ylipäätään. Seerumin biomarkkereiden ja geeniekspression muutosten perusteella nämä vaikutukset johtuvat todennäköisesti luuston uusiutumisen häiriöistä. Yhteenvetona voidaan todeta, että POP-yhdisteet heikentävät luustoa, mutta tämän ilmiön diagnosoiminen on hankalaa, koska huonolaatuisen kuoriluun sisällä hohkaluun määrä on lisääntynyt

Water samples taken from nine English freshwater lakes from a mix of urban, rural, and remote locations on 13 occasions between April 2008 and February 2012 were analysed for selected non-dioxin like-PCBs, tri- through hexa-PBDEs, and the three main HBCD diastereomers (\(\alpha\)-, \(\beta\)-, and \(\gamma\)-HBCD). Concentrations of PCBs and HBCDs declined over the sampling period with half-lives of 3.8 and 5.1 years, respectively. In addition, concentrations of PCBs, HBCDs, tri- through deca-BDEs, and 32 selected NBFRs were measured in radiometrically-dated sediment core slices taken in summer 2011/2 from seven of the same English lakes. Temporal trends in contamination with “legacy” POPs generally accord with historical trends in UK manufacture and use, with PCB contamination at all lakes increasing from ~1950, peaking generally between the late-1960s and mid-1980s, before declining steadily thereafter. In contrast, at most sites, BDE-209 displayed generally smooth increases following its initial emergence, and showed no obvious levelling off trend. Contamination with some NBFRs displayed significantly increasing trends. Spatial variation in POPs contamination of the lakes studied was evident; with regression analysis suggesting concentrations are higher in lakes with surface areas that are small relative to their catchment area, and that are closer to areas of high population density. The estimated PCB burden in the British environment is 521 tons, with TBPH (281 tons) and BDE-209 (147 tons) following not far behind. Estimated UK burdens of the remaining target compounds were significantly lower.

Abstract Persistent organic pollutants (POPs) are ubiquitous and bioaccumulative man-made chemicals, resistant to chemical, biological and photolytic degradation and widely distributed to sediments, wildlife, and human. Many of these chemicals have adverse effects on a variety of targets, including the endocrine system, organogenesis and reproduction. Due to these effects and wide distribution, many of them are either banned or strictly controlled. However, because of persistency, they continue to interact with organisms globally. Despite the existing knowledge of the adverse effects of POPs, the effects of many chemicals on bone tissue are still poorly known. In the present study, we investigated the adverse effects of three common POPs, including tributyltin (TBT), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and perfluorooctanoic acid (PFOA) on the skeletal system. In vitro models were used to study the effects of PFOA in mouse and in human, and the co-effects of TBT and TCDD on differentiating osteoblasts and osteoclasts of mice. An in vivo model for mice was used to study the developmental effects of maternal PFOA-exposure on pups among with morphometrical and biomechanical property analyses. Mass-spectrometry was used to study the presence of PFOA in bones both in mice and in human, the latter acquired from the bone bank held in the Oulu University Hospital, Finland. The bones were also analyzed with cone beam computer tomography and microcomputer tomography. The results show that PFOA exposure in utero and during lactation leads to the accumulation of PFOA in bone, traceable even 17 months after exposure. PFOA exposure decreased the mineral density of the tibias and increased the medullary area. Nearly all of the human samples contained PFAS, including PFOA. PFOA also disturbed the differentiation of osteoblasts and with lower doses, increased bone resorption of osteoclasts both in mouse and human, the phenomenon being slightly stronger in mice. Co-exposure to TBT and TCDD led to decreased differentiation of osteoblasts and osteoclast, and the co-effect was partially synergistic in osteoblasts. These results show disruption of bone development, bone cell differentiation, and PFAS accumulation in bone. Further studies are recommended to evaluate the co-effects of different POPs and the possible effects of long-term accumulation of POPs in bone and other tissues
Tiivistelmä Pysyvät orgaaniset ympäristömyrkyt (POP-yhdisteet) ovat kemikaaleja, jotka ovat levinneet ihmisen toiminnan seurauksena laajalle ympäristöön, sen eliöihin ja ihmisiin. Monilla POP-yhdisteillä on haitallisia vaikutuksia esimerkiksi hormonaaliseen toimintaan, elinten muodostukseen ja hedelmällisyyteen. Toksisten vaikutusten ja niiden yleisyyden vuoksi monien POP-yhdisteiden käyttö on joko rajattua tai kielletty kokonaan. Laajan levinneisyytensä ja hitaan puoliintumisaikansa takia POP-yhdisteet ovat kuitenkin edelleen vuorovaikutuksessa ympäristön ja sen eliöiden kanssa. POP-yhdisteiden luustovaikutuksista tiedetään edelleen vähän. Tässä väitöskirjassa tutkittiin kolmen yleisen POP-yhdisteen, tributyylitinan (TBT), 2,3,7,8-tetraklooridibentso-p-dioksiinin (TCDD) ja perfluoro-oktaanihapon (PFOA), vaikutuksia luustoon. PFOA:n vaikutuksia hiiren ja ihmisen luustoon sekä TBT:n ja TCDD:n yhteisvaikutuksia hiiren erilaistuvien osteoblastien ja osteoklastien suhteen selvitettiin in vitro -malleilla. In vivo -mallilla tutkittiin hiiriemon PFOA-altistuksen vaikutusta syntyvien poikasten luuston kehitykseen ja remodelaatioon analysoimalla poikkileikekuvia sekä luiden biomekaanisia ominaisuuksia. Lisäksi luiden PFOA-pitoisuudet mitattiin massaspektrometrilla. Tutkimusta laajennettiin ihmiseen analysoimalla Oulun yliopistollisen sairaalan luupankkinäytteitä. Ihmisnäytteet analysoitiin myös kartiokeila-TT:n ja mikro-TT:n avulla. Tulosten mukaan PFOA kertyy luuhun; hiiriltä voitiin mitata PFOA-pitoisuuksia jopa 17 kuukautta altistumisen jälkeen. Lisäksi PFOA-altistus pienensi luun mineraalitiheyttä ja kasvatti luuydinontelon tilavuutta. Lähes kaikki ihmisluunäytteet sisälsivät PFOA:ta ja muita PFAS-yhdisteitä. Solukokeiden perusteella PFOA-altistus häiritsee osteoblastien erilaistumista ja pienillä pitoisuuksilla lisää osteoklastien luunhajotusta sekä hiirellä että ihmisellä. TBT:n ja TCDD:n yhteisaltistus vaikuttaa puolestaan vähentävän sekä osteoblastien että osteoklastien erilaistumista ja toimintaa; osteoblastien osalta yhteisvaikutus oli osaksi synergistinen. Väitöskirja antaa lisätietoa POP-yhdisteiden vaikutuksista luun kehitykseen ja luusolujen erilaistumiseen sekä PFAS-yhdisteiden kertymisestä luuhun. Väitöksessä myös suositellaan lisätutkimuksia yhdisteiden yhteisvaikutuksista sekä pitkän aikavälin ympäristökemikaalikertymän vaikutuksista luussa ja muissa kudoksissa

The bioaccumulation of persistent organic pollutants (POPs) is of particular environmental concern in top predators, which accumulate high concentrations of POPs that can cause adverse effects. Previous small scale studies found high concentrations of POPs in adult great skuas, Stercorarius skua, a top predator in the marine environment. This thesis investigates the factors affecting concentrations and patterns of POPs (contribution of individual POPs to the ΣPOPs) in the great skua across its breeding range in the north-east Atlantic. Clear differences between colonies in both concentration and pattern of POPs in adult plasma were not indicative of being caused by long range transport of POPs in the atmosphere. Variation in diet between colonies is the mostly likely explanation for these colony differences, with great skuas from some colonies having a greater proportion of fish in their diet whilst others eat more seabird prey. Although seabirds are often used in studies of POPs in the environment, the effect of migratory behaviour has not previously been studied in detail. By using a combination of global location sensor (GLS) loggers and feather stable isotopes from winter grown feathers, the wintering areas of individuals from three breeding populations of great skuas were identified. Great skuas spend the winter in three distinct areas across the North Atlantic, with birds from the same breeding colonies wintering in different areas. In two of the three breeding populations, wintering area explained a significant proportion of variation in organochlorines (OCs) concentrations and pattern. However in the colony with the highest concentrations of OCs, no effect of wintering area was found, possibly as a result of these great skuas feeding at a higher trophic level during the breeding season than other populations. Temporally, concentrations of OCs were higher in 1980 than 2008 in eggs, whilst newer contaminants polybrominated diphenyl ethers (PBDEs) and perfluorinated chemicals (PFASs) show the opposite trend. In conclusion, concentrations of POPs in the great skua were influenced primarily by breeding season diet with wintering area and sex also having small but significant effects on POPs. Wintering area explained the most variation in the pattern of POPs in great skuas. The POP concentrations found in this study exceeded those which have been found to cause adverse effects on the immune system and reproduction in other species of seabird.

Els Contaminants Organic Persistents (COPs), tals com PCB, PCDD/FS i PAHs, són un grup de compostos químics regulats per a la seva reducció o ja prohibits a causa de la seva persistència, potencial per a ser transportat llargues distàncies i la capacitat de bioacumular en xarxes tròfiques. El transport atmosfèric i la posterior deposició s'han descrit com els processos claus pels quals impacten àrees oceàniques remotes. Així mateix, en la interfície atmòsfera-oceà, que correspon al 70% de la superfície de la Terra, tenen lloc molts processos vitals que determinen el paper dels oceans com a dipòsit i reservori de COPs. La interpretació d'aquests processos no és senzilla a causa de la manca de mesures en àrees remotes de l'oceà i el desconeixement dels mecanismes dominants a diferents escales espacials i temporals.
Aquesta tesi doctoral està centrada en la modelització dels processos de transferència de COPs entre l'atmòsfera i els oceans a escales regionals i globals. Per primera vegada, dades derivades de satèl·lits s'han acoblat amb models multimèdia de contaminants i de caixes de nivell I-III, donant lloc a estimacions d'acord amb un factor de dos amb les measures en molts dels casos. Així mateix, s'ha mostrat la variabilitat dels processos de deposició i la importància de considerar processos biogeoquímics a gran escala quan s'avalua la dinàmica dels COPs. Estimacions globals del procés de deposició atmosfèrica dominant, i fluxes d'enfonsament i subducció també s'han dut a terme. S'ha vist que la difusió aire-aigua és la ruta predominant de introducció de contaminants a oceans per a COPs predominantment en la fase gas. En canvi, la deposició seca i humida és dominant per certes regions i per a contaminants que tendeixen a sorbir-se fortament a aerosols. D'altra banda, la metodologia desenvolupada s'ha implementat per a estimar els bescanvis atmosfera-oceà de carboni orgànic total. Sorprenentment aquestes estimacions apunten a fluxes elevats que podrien ajudar a tancar els balanços globals de carboni.
El destí dels contaminants a curta escala i un cop han entrat a la columna d'aigua s'ha investigat mitjançant un model dinàmic 0-D i un model acoblat hidrodinàmic-contaminant 1-D. S'ha recalcat el paper dels sediments en el reciclatge de contaminants i dels fluxes atmosfèrics. Així mateix s'ha vist que la influència dels sediments és especialment important per a aigües poc profundes (< 20 m) i la profunditat a la qual difonen en la columna d'aigua s'explica amb la interacció entre fluxes turbulents i d'enfonsament. Així doncs, en aquesta tesi i per primera vegada s'ha dut a terme un analisi exhaustiu de la turbulència vertical en la dinàmica dels COPs
Tots aquests resultats es presenten en forma d'articles científics que han estat ja publicats o en procés de publicació.
Persistent organic pollutants (POPs), such as PCB, PCDD/FS and PAHs, are a group of chemicals targeted for reduction, or already banned, because of their persistence, potential for long-range transport and their ability to bioaccumulate in food-webs. Atmospheric transport and subsequent deposition has been described as the major process by which they impact remote oceanic areas. Additionally in the air-water interface, which accounts about the 70% of the Earth surface, take place many vital processes that determine the role of the oceans as a sink and as a reservoir of POPs. However the interpretation of these processes encounters difficulties because of the lack of measurements in the remote oceanic areas, and the lack of understanding of the dominant mechanisms at different spatial and temporal scales.
This PhD-thesis focuses on the modelling of the transfer processes of POPs between the atmosphere and the oceans at regional and global scales. Satellite derived data has been coupled with multimedia box-contaminant models of level I-III for the first time, yielding estimations in agreement within a factor of two with measurements, in most cases. Moreover, it is shown the noteworthy variability of atmospheric depositional fluxes and the importance of considering large biogeochemical processes in the oceans when evaluating the dynamics of POPs. Global estimations of the dominant atmospheric depositional, sinking and subduction fluxes have been also performed. It is seen that diffusive air-water exchange is the predominant route of introduction of contaminants to the oceans for POPs predominantly in the gaseous phase. However, dry and wet deposition become dominant in certain ocean regions and for compounds that sorb strongly to aerosols. Furthermore the developed methodology has also been implemented to estimate the atmosphere-ocean exchanges of total organic carbon. Surprisingly, these estimations point to high fluxes which could help to close the carbon budgets in the global carbon models.
The fate of contaminants on the short-time scale and once they enter the water column has been investigated by means of a 0-D dynamic model and a 1-D dynamic coupled contaminant-hydrodynamic model. It is stressed the role of sediments recycling contaminants and the atmospheric based fluxes. The influence of sediments is especially important for shallow water columns (< 20 m). The extent to which they diffuse in the water column is explained by the interplay between sinking and turbulent fluxes. In this thesis and for the first time a novel and comprehensive analysis of the vertical turbulence to the dynamics of POPs has been performed.
All these results have been published in scientific literature, are in press for publication or under review.

The present research explores the levels and patterns of accumulation of a wide range of persistent organic pollutants (POPs) in the human population. It assesses two major families of POPs, namely organochlorine compounds (OCs) and polybrominated diphenyl ethers (PBDEs), and focuses on the population of Catalonia, a Mediterranean country in South-West Europe with active agricultural and industrial sectors. The research described in this study is based on a public health survey conducted by the Government of Catalonia in 2002, which included a health exam and a blood testing for 919 individuals. Gas chromatography and mass spectrometry techniques have been used to determine the concentrations of these pollutants in the serum samples. This research has customised a methodology to better detect organochlorine compounds in human serum samples. It has also contrasted the POP concentrations with a set of socio-demographic factors, with a special focus on age, sex and body mass index (BMI). And nally, it provides complementary assessments on POPs in other locations of Catalonia, including the Flix township that hosts a chemical factory; and on mercury, which is a non-organic persistent pollutant, in the infant population of the Menorca island. In essence, this research navigates in a diversity of pollutants, research methodologies and geographic conditions to explore the linkages between environmental pollution and human health.
Aquest estudi avalua els nivells i els patrons d'acumulació d'un ampli ventall de contaminants orgànics persistents (COPs) en la població humana. Comprèn dues classes de COPs, específicament els compos- tos organoclorats (OCs) i els polibromodifenil eters (PBDEs), i se centra en la població de Catalunya, un país mediterrani del sud-oest d'Europa amb uns sectors agrícola i industrial actius. La recerca descrita en aquest estudi es basa en una enquesta de salut pública duta a terme per la Generalitat de Catalunya el 2002, que va incloure en examen de salut i l'extracció d'una mostra de sang per a 919 persones. Les concentracions d'aquests contaminants en les mostres de s erum es van determinat mitjan cant t ecniques de cromatogra a de gasos i espectrometria de masses. En aquesta recerca s'ha dissenyat una metodologia específica per tal de millorar la detecció dels compostos organoclorats en mostres de sèrum humà. A més, les concentracions de COPs s'han contrastat amb una sèrie de factors sòcio-demogràfics, amb una especial atenció al sexe, l'edat i l' índex de massa corporal (IMC). Finalment, l'estudi proporciona avaluacions complementàries sobre els COPs en altres llocs de Catalunya, incloent el municipi de Flix, que acull una fàabrica de productes químics; i sobre el mercuri, un contaminant persistent inorgànic, a la població infantil de l'illa de Menorca. En resum, aquesta recerca combina una diversitat de contaminants, mètodes analítics i àrees geogrà ques per tal d'explorar l'associació entre la contaminació medioambiental i la salut humana.

The present research explores the levels and patterns of accumulation of a wide range of persistent organic pollutants (POPs) in the human population. It assesses two major families of POPs, namely organochlorine compounds (OCs) and polybrominated diphenyl ethers (PBDEs), and focuses on the population of Catalonia, a Mediterranean country in South-West Europe with active agricultural and industrial sectors. The research described in this study is based on a public health survey conducted by the Government of Catalonia in 2002, which included a health exam and a blood testing for 919 individuals. Gas chromatography and mass spectrometry techniques have been used to determine the concentrations of these pollutants in the serum samples. This research has customised a methodology to better detect organochlorine compounds in human serum samples. It has also contrasted the POP concentrations with a set of socio-demographic factors, with a special focus on age, sex and body mass index (BMI). And nally, it provides complementary assessments on POPs in other locations of Catalonia, including the Flix township that hosts a chemical factory; and on mercury, which is a non-organic persistent pollutant, in the infant population of the Menorca island. In essence, this research navigates in a diversity of pollutants, research methodologies and geographic conditions to explore the linkages between environmental pollution and human health.
Aquest estudi avalua els nivells i els patrons d'acumulació d'un ampli ventall de contaminants orgànics persistents (COPs) en la població humana. Comprèn dues classes de COPs, específicament els compos- tos organoclorats (OCs) i els polibromodifenil eters (PBDEs), i se centra en la població de Catalunya, un país mediterrani del sud-oest d'Europa amb uns sectors agrícola i industrial actius. La recerca descrita en aquest estudi es basa en una enquesta de salut pública duta a terme per la Generalitat de Catalunya el 2002, que va incloure en examen de salut i l'extracció d'una mostra de sang per a 919 persones. Les concentracions d'aquests contaminants en les mostres de s erum es van determinat mitjan cant t ecniques de cromatogra a de gasos i espectrometria de masses. En aquesta recerca s'ha dissenyat una metodologia específica per tal de millorar la detecció dels compostos organoclorats en mostres de sèrum humà. A més, les concentracions de COPs s'han contrastat amb una sèrie de factors sòcio-demogràfics, amb una especial atenció al sexe, l'edat i l' índex de massa corporal (IMC). Finalment, l'estudi proporciona avaluacions complementàries sobre els COPs en altres llocs de Catalunya, incloent el municipi de Flix, que acull una fàabrica de productes químics; i sobre el mercuri, un contaminant persistent inorgànic, a la població infantil de l'illa de Menorca. En resum, aquesta recerca combina una diversitat de contaminants, mètodes analítics i àrees geogrà ques per tal d'explorar l'associació entre la contaminació medioambiental i la salut humana.

Despite the apparent pristine conditions and remoteness of Antarctica, persistent organic pollutants (POPs) have been detected in the Antarctic ecosystem since the 1960s. Today, a variety of organic pollutants can be found in Antarctica, often concentrated in local biota. In this thesis I investigate four system input pathways for POPs to Australian Antarctic territory, Eastern Antarctica. This work has been conducted with the purpose of contributing to an understanding of the possible impacts of these pollutants under present and projected climate conditions, as well as establishing robust baselines from which to monitor temporal and spatial trends. The first long range environmental transport (LRET) pathway investigated was the introduction of POP via long range atmospheric transport (LRAT). Transport was assessed via high flow-through passive air sampling at Casey Station between 2009 and 2013, with sample changeover every 1 to 3 months. The results of this study present the first continuous, multi-year sampling effort for POPs originating from the Eastern Antarctic sector. The POP profile presented is distinct from other regions and is characterised by a dominance of agricultural, rather than manufacturing, chemicals, particularly hexachlorobenzene (HCB) and endosulfan. The study also presents the first reported occurrence of endosulfan in air masses on the Antarctic continent, providing evidence of the LRAT capabilities of this compound. Whilst a moderate data timespan of four years is presented, it is projected that continual monitoring at the decadal scale would be required to detect a 5% change in levels with 80% confidence, emphasising the importance of long term monitoring efforts.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text

Global atmospheric transport has led to the dispersal of many Persistent Organic Pollutants (POPs) generated at lower latitudes, allowing them to reach Polar latitudes. Although the ice has long been considered simply as a means of immobilising these toxic chemicals, it is in fact an annual source to the local environment during seasonal spring melt. This results in pulse exposure to Polar biota during summer periods of high marine productivity. In the global warming context, the progressive melt of ice shelves is also expected to release historically trapped POPs back into the local environment. This PhD study was designed around a growing need to understand environmental chemical partitioning, as part of resolving biogeochemical cycling uncertainties of these chemicals in the Polar landscape. The aims of this PhD were a) to acquire empirical data regarding POP partitioning and determine the associated air-seawater exchange status in the marine environment of the Indian-Pacific sector of the Southern Ocean, b) to investigate and compare Arctic and Antarctic air/snow/sea-ice/seawater POP reservoirs and their dynamics during spring and c) to evaluate the potential to determine historical POP accumulation levels from archived Antarctic firn cores.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text

Introduction Diet is the main source of exposure to persistent organic pollutants (POPs), including dioxins and PCBs. During pregnancy the fetus is exposed to POPs which can lead to adverse health effects. The research hypothesis of this thesis is that maternal diet, as a source of prenatal exposure to POPs, may be linked to impaired fetal growth and endocrine disruptive effects. Methods This thesis included 604 mother-child pairs from the European NewGeneris project, 50,651 mother-child pairs from the Norwegian Mother and Child Cohort (MoBa) and 707 mother-child pairs from the Rhea and the Hmar studies. Dietary data were collected during pregnancy by food frequency questionnaires. Three approaches were used to derive dietary estimates of prenatal exposure, either related to levels of POPs in maternal and cord blood or in food. Birth outcome information was obtained by medical registries. Anogenital distance measurements were collected and used as a marker of endocrine disruptive effects. Main predictors of anogenital distance were assessed and a reliability study was conducted. Results In the NewGeneris project, a dioxin-diet characterized by high maternal intakes of meat and fish was positively related to dioxins and dioxin-like compounds in maternal blood. High adherence to the dioxin-diet was associated with a reduction of -115g in birth weight. In the MoBa study, an inverse dose-response association was found between dietary dioxins and PCBs intakes during pregnancy and birth size. The negative association remained even for intakes lower than the tolerable weekly intake. In the Rhea and Hmar studies, anogenital distances were related to growth, tracked through early life and were highly reliable anthropometric measurements. A high-fat diet score during pregnancy was positively related to POPs in maternal blood and was associated with 15% reduction in anogenital distance of newborn boys. Conclusions Diet during pregnancy can influence maternal and fetal body burden of POPs. Prenatal exposure to POPs, through maternal diet, may lead to impaired fetal growth and endocrine disruptive effects, even in populations with low background exposures to POPs.
Introducció La dieta és la principal font d'exposició als contaminants orgànics persistents (COP), com les dioxines i els PCBs. Durant l'embaràs el fetus està exposat als COPs, que poden donar lloc a efectes adversos per a la salut. La hipòtesi principal d'aquesta tesi és que la dieta materna, com una font d'exposició prenatal als COPs, podria estar relacionada amb alteracions en el creixement fetal i efectes endocrins perjudicials. Mètodes En aquesta tesi es van incloure 604 parelles mare-fill del projecte europeu NewGeneris, 50.651 parelles mare-fill de la cohort noruega (MOBA) i 707 parells de mares i fills dels estudis RHEA (Grècia) i Hmar (Catalunya). Les dades dietètiques es van recollir durant l'embaràs mitjançant qüestionaris de freqüència d'aliments. Tres mètodes s'han aplicat per derivar estimacions de l'exposició dietètica prenatal, ja sigui en relació als nivells de COP en la sang materna i del cordó o en els aliments. Informació sobre el naixement va ser obtinguda pels registres mèdics. Mesures de les distàncies anogenitals es van recollir i s'han utilitzat com marcadors d'efectes endocrins pertorbadors. Els determinants principals de la distància anogenital van ser avaluats i es va fer un estudi de fiabilitat de les mesures. Resultats En el projecte NewGeneris, una dieta alta en dioxines es caracteritza per una alta ingesta materna de carn i peix, i estava positivament relacionada amb dioxines i compostos similars a les dioxines a la sang materna. Alta adherència a una dieta alta en dioxines es va associar amb una reducció de 115 g de pes al néixer. En l'estudi Moba, es va trobar una relació de dosi-resposta inversa entre la ingesta de dioxines i PCBs durant l'embaràs i el pes en néixer. L'associació es va mantenir fins i tot per una ingesta inferior al límit de ingesta tolerable. En els estudis Rhea i Hmar, les distàncies anogenitals estan relacionades amb el pes al néixer, les mesures al naixement s’associaven amb aquestes dels primers anys de vida, i les mesures antropomètriques van ser altament fiables. Una dieta alta en greixos durant l'embaràs va ser positivament relacionada amb els COP en la sang materna i es va associar amb un 15% de reducció en la distància anogenital dels nounats. Conclusions La dieta durant l'embaràs pot influir en la càrrega corporal materna i fetal dels COP. L'exposició prenatal als COP, a través de la dieta materna, pot conduir a alteracions en el creixement fetal i als efectes pertorbadors endocrins, fins i tot en poblacions amb exposicions sota els límits d’ingesta estipulats.

In this study, the Persistent Organic Pollutants (POPs) specifically
17 Organochlorine Pesticides (OCPs) and 19 Polycyclic Aromatic Hydrocarbons (PAHs) were evaluated in the sediment samples of Balikesir (Ikizcetepeler) Dam Lake. Sixteen sampling points were chosen for determination of concentrations of OCPs and PAHs After ultrasonic bath extraction of the sediment samples GC-MS was used as analytical tool. Extraction efficiencies changes from 63.8 to 87.4% depending on the type of the POPs. Average OCP concentration was found in the range of 3.33-379 µ
g/kg a, average PAH concentration was found in the range of 3.28-32.9 µ
g/kg. Pollution maps regarding OCP and PAH distributions were drawn and the correlation between these two pollutant types was investigated. The quality control (QC) and quality assurance tests were applied by the analysis of standard reference materials (SRMs), surrogate standards and analysis replicates.

Many persistent organic pollutants (POPs) are chiral. These pollutants are generally released into the environment as racemates, but frequently undergo alterations in enantiomeric composition as soon as they are subjected to life chemistry processes. Enantiospecific analysis of chiral POPs is important since enantiomers of chiral compounds often exhibit differences in biological activity, and most biochemical processes in nature are stereospecific. For abiotic processes, such as air-water gas exchange, deposition and long-range air transport, enantiomeric patterns of POPs may be used as chemical markers. The aim of the work described in this thesis was to improve our knowledge about the presence and fate of enantiomers of chiral POPs inthe environment to provide a sound basis for accurate risk assessment. The compounds included were organochlorine (OC) pesticides (α-HCH, chlordanes and o,p’-DDT), atropisomeric PCBs and some of their respective metabolites (heptachlor-exo-epoxide, oxychlordane and MeSO2-PCBs). Analytical methods for chiral PCBs were developed, and the elution sequences of (+) and (−)-enantiomers were determined. Enantiomeric fraction (EF) was proposed as a better reflector of chiral composition than the conventional enantiomeric ratio (ER). Enantioselective bioprocessing in various compartments was studied, with the main emphasis on factors controlling chiral composition in biota Correlations were detected between changes in EFs and differences in trophic levels. The changes were, however, not consistent for all compounds. Instead, the enantiomeric composition was found to be species-specific in the polar bear food chain and in aquatic species from the Baltic Sea. The EFs of some POPs in Baltic seals were related tonutritional status and biotransformation capacity. Enantiomeric and isomeric patterns were used to investigate abiotic processes in the southern Baltic Sea environment and EFs were used tostudy soil as a source of atmospheric heptachlor-exo-epoxide.

This thesis attempts to logically follow the full lifecycle of a 'new' persistent organic pollutant (POP), perfluorooctane sulfonate (PFOS). A new estimate of the global historical production for perfluorooctane sulfonyl fluoride (POSF) was produced, before focusing on deriving the first estimate of the global historical environmental releases of PFOS. The total historical worldwide production of POSF was estimated to be 96,000 tonnes between 1970- 2002, with an estimated global release of 45,250 t to air and water between 1970-2012. Estimates indicated POSF-derived products are the major direct source of PFOS emissions, resulting in an estimated release of 450-2700 t into wastew31er streams over the same period. Due to the physiochemical properties of PFOS (soluble in water, negligible vapour pressure, and limited sorption to particles), emissions from consumer products including stain repellent treated fabrics, waterproof apparel, and aqueous fire fighting foams were expected to be largely to waste water. The following papers saw two existing multi-media environmental fate models reparameterised to explore the role of emissions from diffuse consumer use. PFOS emissions were linked to waste water treatment plants, partitioning and emissions uncertainty were explored, and annual fluxes of PFOS were estimated from European rivers at a local and continental scale. A good agreement, generally within a factor of three between modelled emissions derived from population density and measured freshwater PFOS concentrations, was observed. The final paper is a slight departure from the others submitted in this thesis. This paper returns to 'classical' POPs, but looks forward in time to try and understand the potential impact of climate change on POP chemicals. Overall. predicted changes were small even under the most conservative scenarios, resulting in slightly increased volatilisation and degradation in air from a drier and warmer south-western Europe, corresponding to a transfer and redeposition of POPs to the cooler and wetter north-eastern Europe.

Introduction Diet is the main source of exposure to persistent organic pollutants (POPs), including dioxins and PCBs. During pregnancy the fetus is exposed to POPs which can lead to adverse health effects. The research hypothesis of this thesis is that maternal diet, as a source of prenatal exposure to POPs, may be linked to impaired fetal growth and endocrine disruptive effects. Methods This thesis included 604 mother-child pairs from the European NewGeneris project, 50,651 mother-child pairs from the Norwegian Mother and Child Cohort (MoBa) and 707 mother-child pairs from the Rhea and the Hmar studies. Dietary data were collected during pregnancy by food frequency questionnaires. Three approaches were used to derive dietary estimates of prenatal exposure, either related to levels of POPs in maternal and cord blood or in food. Birth outcome information was obtained by medical registries. Anogenital distance measurements were collected and used as a marker of endocrine disruptive effects. Main predictors of anogenital distance were assessed and a reliability study was conducted. Results In the NewGeneris project, a dioxin-diet characterized by high maternal intakes of meat and fish was positively related to dioxins and dioxin-like compounds in maternal blood. High adherence to the dioxin-diet was associated with a reduction of -115g in birth weight. In the MoBa study, an inverse dose-response association was found between dietary dioxins and PCBs intakes during pregnancy and birth size. The negative association remained even for intakes lower than the tolerable weekly intake. In the Rhea and Hmar studies, anogenital distances were related to growth, tracked through early life and were highly reliable anthropometric measurements. A high-fat diet score during pregnancy was positively related to POPs in maternal blood and was associated with 15% reduction in anogenital distance of newborn boys. Conclusions Diet during pregnancy can influence maternal and fetal body burden of POPs. Prenatal exposure to POPs, through maternal diet, may lead to impaired fetal growth and endocrine disruptive effects, even in populations with low background exposures to POPs.
Introducció La dieta és la principal font d'exposició als contaminants orgànics persistents (COP), com les dioxines i els PCBs. Durant l'embaràs el fetus està exposat als COPs, que poden donar lloc a efectes adversos per a la salut. La hipòtesi principal d'aquesta tesi és que la dieta materna, com una font d'exposició prenatal als COPs, podria estar relacionada amb alteracions en el creixement fetal i efectes endocrins perjudicials. Mètodes En aquesta tesi es van incloure 604 parelles mare-fill del projecte europeu NewGeneris, 50.651 parelles mare-fill de la cohort noruega (MOBA) i 707 parells de mares i fills dels estudis RHEA (Grècia) i Hmar (Catalunya). Les dades dietètiques es van recollir durant l'embaràs mitjançant qüestionaris de freqüència d'aliments. Tres mètodes s'han aplicat per derivar estimacions de l'exposició dietètica prenatal, ja sigui en relació als nivells de COP en la sang materna i del cordó o en els aliments. Informació sobre el naixement va ser obtinguda pels registres mèdics. Mesures de les distàncies anogenitals es van recollir i s'han utilitzat com marcadors d'efectes endocrins pertorbadors. Els determinants principals de la distància anogenital van ser avaluats i es va fer un estudi de fiabilitat de les mesures. Resultats En el projecte NewGeneris, una dieta alta en dioxines es caracteritza per una alta ingesta materna de carn i peix, i estava positivament relacionada amb dioxines i compostos similars a les dioxines a la sang materna. Alta adherència a una dieta alta en dioxines es va associar amb una reducció de 115 g de pes al néixer. En l'estudi Moba, es va trobar una relació de dosi-resposta inversa entre la ingesta de dioxines i PCBs durant l'embaràs i el pes en néixer. L'associació es va mantenir fins i tot per una ingesta inferior al límit de ingesta tolerable. En els estudis Rhea i Hmar, les distàncies anogenitals estan relacionades amb el pes al néixer, les mesures al naixement s’associaven amb aquestes dels primers anys de vida, i les mesures antropomètriques van ser altament fiables. Una dieta alta en greixos durant l'embaràs va ser positivament relacionada amb els COP en la sang materna i es va associar amb un 15% de reducció en la distància anogenital dels nounats. Conclusions La dieta durant l'embaràs pot influir en la càrrega corporal materna i fetal dels COP. L'exposició prenatal als COP, a través de la dieta materna, pot conduir a alteracions en el creixement fetal i als efectes pertorbadors endocrins, fins i tot en poblacions amb exposicions sota els límits d’ingesta estipulats.

Philosophiae Doctor - PhD
Persistent organic pollutants (POPs) are very tenacious wastewater contaminants with negative impact on the ecosystem. The two major sources of POPs are wastewater from textile industries and pharmaceutical industries. They are known for their recalcitrance and circumvention of nearly all the known wastewater treatment procedures. However, the wastewater treatment methods which applied advanced oxidation processes (AOPs) are documented for their successful remediation of POPs. AOPs are a group of water treatment technologies which is centered on the generation of OH radicals for the purpose of oxidizing recalcitrant organic contaminants content of wastewater to their inert end products. Circumvention of the reported demerits of AOPs such as low degradation efficiency, generation of toxic intermediates, massive sludge production, high energy expenditure and operational cost can be done through the application of the combined AOPs in the wastewater treatment procedure. The resultant mineralisation of the POPs content of wastewater is due to the synergistic effect of the OH radicals produced in the combined AOPs. Hydrodynamic cavitation is the application of the pressure variation in a liquid flowing through the venturi or orifice plates. This results in generation, growth, implosion and subsequent production of OH radicals in the liquid matrix. The generated OH radical in the jet loop hydrodynamic cavitation was applied as a form of advanced oxidation process in combination with hydrogen peroxide, iron (II) oxides or the synthesized green nano zero valent iron (gnZVI) for the treatment of simulated textile and pharmaceutical wastewater.

Bulk atmospheric deposition samples using Amberlite IRA- 743 as an absorbent for hydrophobic pollutants were taken every two months for one year at two different locations in northern Sweden. A method was developed for the analysis of various legacy and emerging POPs in these samples based on GC-HRMS. Two current use pesticides and four flame retardants, which have scarcely or never been detected in the arctic, were detected in the samples: trifluralin, chlorothalonil, TBECH, HBB, BTBPE, and Dechlorane Plus. Legacy compounds including isomers of HCH, PCBs, DDT and metabolites, and chlordane related compounds were quantified in levels comparable to similar studies. The method showed reasonable recoveries for all compounds except endosulfan, HBB, BTBPE, lindane, and highly chlorinated PCBs. It is recommended that the method be optimized for the compounds with low recoveries if it is to be used again.

The accumulation of persistent organic pollutants (POPs) in mountain regions was investigated by collecting trout from eight lakes spanning an elevation gradient of 760 to 2360 m.a.s.l. in the Canadian Rocky Mountains. All lakes were located within (or close to) national parks in Alberta and British Columbia. Concentrations of several organochlorine compounds increased significantly with lake elevation. The compounds, which increased the most with elevation, were the less volatile organochlorine pesticides (OCPs) (e.g. dieldrin, DDTs). The relationship was not as strong for the more volatile organochlorines (e.g. HCHs, HCB). Biological factors such as growth dilution of contaminants appears to be a major determinant of contaminant concentrations of organochlorine compounds in alpine lakes. Principal component analysis (PCA) showed that POP composition in trout relate strongly to octanol/water partition co-efficient (Kow) and lake elevation.

Persistent organic pollutants (POPs), bisphenol A (BPA) and pthalates may increase the risk of respiratory infections and allergic diseases in infants and the effects might last until, at least, adolescence. Cytokines and biomarkers of inflammation can provide information of the mechanisms behind such associations. Data from the “Infancia y Medioambiente” (INMA) population-based birth cohort project and from six other existing European birth cohort studies have been used in the present thesis, which also includes a systematic review. Results of the present work, which includes five scientific publications, suggest that prenatal exposure to POPs affects the immune and respiratory health of children, that the effects are observed even at low levels of exposure and that these may last until adolescence. Biological mechanisms behind such effects were not possible to describe in the present thesis, however, it provided information of a potential biomarker (interleukin 10) of chronic immunotoxic effects of POPs. Results also indicate potential effects of prenatal exposure to BPA and phthalates on the development and functioning of the immune and respiratory systems of infants and children. In the present thesis we highlight the limitations of existing studies in the field and provide recommendations for future research.
Els compostos orgànics persistents (COPs), el bisfenol A (BPA) i els ftalats podrien estar relacionats amb un increment del risc de patir infeccions respiratòries i símptomes relacionats amb l’al•lèrgia en infants i fins, com a mínim, l’adolescència. Les citoquines i els marcadors d’inflamació poden aportar informació dels mecanismes que hi ha darrera d’aquestes associacions. En la present tesis s’han utilitzat dades de la cohort de naixement “Infancia y Medioambiente” (INMA) i de sis cohorts de naixement Europees. La tesis també inclou una revisió sistemàtica. Els resultats d’aquest treball, que inclou cinc publicacions científiques, suggereixen que l’exposició prenatal a COPs afecta els sistemes immunitari i respiratori dels infants i nens, que aquests efectes es donen inclús a exposicions relativament baixes i que aquests efectes poden perdurar fins a l’adolescència. Els mecanismes biològics que podrien explicar els efectes observats no s’han pogut descriure en el present treball, tot i així, hem aportat informació d’un possible biomarcador (interleuquina 10) dels efectes immunotòxics crònics dels COPs. Els resultats també mostren efectes potencials de l’exposició prenatal a BPA i ftalats sobre el desenvolupament i funcionament dels sistemes immunitari i respiratori dels infants i nens. A la present tesis es remarquen les principals limitacions dels estudis existents en aquest camp i es proposen recomanacions de millora per a futurs estudis. Mentrestant, es recomana revisar la legislació actual per tal de reduir l'ús d'aquells compostos que encara estan al mercat i que s'utilitzen àmpliament.

This thesis examines the accumulation of persistent organochlorine compounds in Canadian mountain environments through the sampling of air and coniferous vegetation along a 1430-meter elevation gradient in the Canadian Rocky Mountains. Results showed that lower temperatures encountered in high altitudes favor the accumulation of chemicals with higher volatility in vegetation. Air concentrations further suggest that the reason for this accumulation in elevated areas is increased atmospheric deposition from distant sources and not from temperature-induced revolatilization from local terrestrial surfaces. Seasonal decreases in plant concentrations indicate evaporative processes, and volatilization from vegetation was confirmed by calculated fugacity gradients. However, volatilization contributes very little to air concentrations and the subsequent fractionation upslope, which appears to be dominated by long-range transport. Multivariate analysis revealed that, in addition to cooler temperatures, other environmental conditions common to mountain ecosystems, such as elevated precipitation and lower pressure, promote chemical deposition onto vegetation.

Rising levels of persistent organic pollutants (POPs) in the environment have spurred governments around the world to engage in cooperative action on a global scale to control those chemicals that pose significant threats to human health and the environment. Political efforts to mitigate the risks posed by these chemicals are impeded by the technical complexity associated with POPs pollution, and are thus predicated on the scientific assessments of experts in fields such as chemistry and toxicology. Policymakers’ reliance on scientific expertise for guidance on risk assessment and management has reduced their control over policy and has given scientists authority to determine socially acceptable levels of risk, thus blurring the boundaries between science and politics. Conversely, the implications of science-based decision-making have increased the interest and involvement of political actors in a phase of evaluation that is often seen as objective, fact-based, and free of political interest. This thesis analyzes the ways in which various actors with scientific expertise – representatives of governments, industry, and environmental/public health NGOs – working under the auspices of the Stockholm Convention on Persistent Organic Pollutants have used strategic issue framing tactics to promote predetermined policy agendas during the scientific review of chemicals proposed for regulation. This research breaks new ground by analyzing the ways elite decision-makers strategically frame issues in order to influence the policy preferences of other elites, and by evaluating the role of issue framing in the context of live policy negotiations. Key findings include the following: 1) the formation of epistemic communities of technical experts is precluded by political pressure on scientists to represent government/organizational interests, and 2) scientists strategically frame issues in ways that support the social, economic or political interests of the governments or organizations with which they are affiliated, thus contributing to the politicization of science-based decision-making.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 103-109).
In this thesis, I study polycyclic aromatic hydrocarbons (PAHs) and perfluorocarboxylic acids (PFCAs). PAHs are by-products of burning and therefore have important anthropogenic sources in the combustion of fuels, biomass, etc. PFCAs and their atmospheric precursors are used in making firefighting foams, non-stick coatings, and other surfactant applications. I quantitatively examine the relative importance of uncertainty in emissions and physicochemical properties (including reaction rate constants) to Northern Hemisphere (NH) and Arctic PAH concentrations. NH average concentrations are more sensitive to uncertainty in the atmospheric lifetime than to emissions rate. The largest uncertainty reductions would come from precise experimental determination of PHE, PYR and BaP rate constants for the reaction with OH. I calculate long-chain PFCA formation theoretical maximum yields for the degradation of precursor species at a representative sample of atmospheric conditions from a three dimensional chemical transport model, finding that atmospheric conditions farther from pollution sources have both higher capacities to form long chain PFCAs and higher uncertainties in those capacities. I present results from newly developed simulations of atmospheric PFCA formation and fate using the chemical transport model GEOS-Chem, simulating the degradation of fluorotelomer precursors, as well as deposition and transport of the precursors, intermediates and end-products of the PFCA formation chemistry. I compare the model results to remote deposition measurements and find that it reproduces Arctic deposition of PFOA effectively. Given the most recent precursor emission inventory, the atmospheric indirect source of PFOA and PFNA is 10-45 t/yr globally and 0.2-0.7 t/yr to the Arctic.
by Colin Michael Pike-Thackray.
Ph. D.

The worldwide prevalence of obesity and obesity-associated liver diseases have attracted great attention in the past decades. Obesity is an increasing health problem, which can induce a series of metabolic syndrome associated diseases, such as fatty liver disease, type 2 diabetes. The conventional causes for obesity, such as over-eating, sedentary life-style, and genetic factors, cannot fully explain the global rapid increase of obese population in the last few decades. It was found that the production of persistent organic pollutants (POPs) in the industry was closely correlated with the prevalence of obesity. POPs are organic chemicals that are resisted to degrade by various processes and widely applied in daily products to improve the quality of our life. 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is the most abundant and toxic congener in the family of polybrominated diphenyl ethers (PBDEs), which are the commonly used flame retardants and listed as POPs in 2009. High concentration of BDE-47 has been found in indoor dust and marine fish in Hong Kong. Owing to their high lipophilic and persistent characters, BDE-47 is mainly accumulated in adipose tissue. Epidemiological data indicates that exposure to BDE-47 is associated with obesity and obesity-associated liver diseases. Therefore, based on published research, we hypothesize that BDE-47 exposure may increase the occurrence of obesity and aggravate the progression of obesity-associated fatty liver disease through promoting adipocyte differentiation and impairing lipid metabolism. To verify this hypothesis, mouse preadipocytes (3T3-L1 cells) were exposed to BDE-47 and differentiated into adipocytes. Excitedly, with BDE-47 exposure, more lipid droplets were formed and accumulated in the treated cells than that in untreated adipocytes (without BDE-47 exposure). Along with the increased content of triglyceride accumulation, augmented gene and protein levels of transcription factors (PPARγ and PGC-1α), and related genes (FABP4 and C/EBPα) were also detected in BDE-47 treated cells. In addition, the total production of reactive oxygen species (ROS), contents of lipid peroxidation and DNA oxidation were obviously increased in adipocytes treated with BDE-47 (10 μM). To explore how BDE-47 regulated the oxidative stress signal pathways, antioxidants of ROS sources were employed with BDE-47 exposure during adipocyte differentiation. Notably, mitochondrial respiration, xanthine oxidase and NADPH pathway were significantly influenced by BDE-47 exposure to generate ROS in the treated adipocytes. The effects of BDE-47 on mitochondrial respiration were also determined for further exploring the relationship between mitochondrial ROS and adipocyte differentiation. Significant elevation of mitochondrial ROS was detected in adipocytes exposed with BDE-47 (10 μM). Furthermore, to support the energy requirements for the growth of adipocytes during differentiation process, BDE-47 improved the mitochondrial metabolism for ATP production via increasing the spare mitochondrial respiration capacity. Inhibiting the mitochondrial ROS generation in BDE-47-treated adipocytes with antioxidant attenuated the generation of ROS and reduced the accumulation of lipid droplets as well. This phenomenon indicated that the ROS-induced by BDE-47 through mitochondrial chain was critical for adipocyte differentiation. Global metabolomic profiling based on high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was performed on differentiated 3T3-L1 cells to reveal the metabolic changes induced by BDE-47. Twenty three significantly changed metabolites were identified in the adipocytes after BDE-47 exposure. The results of pathway analysis showed that purine and glutathione metabolism were the main impacted pathways and upregulated by BDE-47 treatment. In purine metabolism, increasing levels of adenosine monophosphate (AMP) and guanosine monophosphate (GMP) induced by BDE-47 led to the increment of inosine 5'-monophosphate (IMP) in adipocytes. These increases forwarded the pathway and caused high production of uric acid along with hydrogen peroxide, which contributed to the elevation of ROS after exposure to BDE-47. Inhibiting the synthesis of uric acid with antioxidant could significantly decrease the production of ROS, the levels of adipogenesis-related genes, and the accumulation of lipid droplets in BDE-47 exposed adipocytes. These results further demonstrated that exposure to BDE-47 promoted adipocyte differentiation via causing oxidative stress, upregulating purine metabolism, and increasing production of uric acid. Subsequently, C57BL/6J mouse model with diet interaction was employed to explore the obesogenic effects of BDE-47. Male C57BL/6J mice were fed with either a low-fat diet (LFD, 10% fat) or high-fat diet (HFD, 60% fat) for 15 weeks and subcutaneously injected with BDE-47 (7mg/kg [Low dose, L] or 70mg/kg [High dose, H]) or the vehicle weekly. It was found that exposure to BDE-47 (H) significantly led to the elevation of body weight and serum triglyceride content in HFD fed mice. Besides, the combination of BDE-47 and HFD also significantly increased the weight of white adipose tissue (WAT) and augmented the size of adipocytes in WAT. These have confirmed the obesogenic effects of BDE-47 in vivo. Additionally, BDE-47 (H) exposure significantly increased the accumulation of hepatic triglyceride content and lipid droplets accompanying with elevated inflammation in HFD fed mice, indicating the deterioration of hepatic steatosis in BDE-47 treated mice. Moreover, the integration analysis of lipidomic and gene expression revealed that BDE-47 up-regulated triglyceride synthesis but suppressed lipid exportation and β oxidation to impair the lipid metabolism and worsen the accumulation of hepatic lipid in HFD fed mice. In addition, the increase of liver fibrosis scars (the protein level of αSMA and collagens), serum transaminase levels, as well as lipid peroxidation have been detected in the mice with co-treatment of BDE-47 and HFD. BDE-47 exposure also increased the production of ROS and the levels of fibrotic genes in hepatocytes. However, in LFD with BDE-47 exposed mouse liver, we cannot observe such changes compared with the control (LFD-DMSO). Interestingly, the application of antioxidants reversed the BDE-47-induced fibrotic responses (the expression of αSMA and col3) in hepatocytes, which indicated that the increase of liver fibrosis scars was tightly associated with the level of oxidative stress. In conclusion, these results offered a new insight of lipid toxicities and underlying mechanism of BDE-47 induced obesity-related liver fibrosis. As far as we know, this is the first systematic study of the obesogenic effects and underlying mechanisms of BDE-47 in diet-induced mouse model. These results have showed the pathological roles of BDE-47 in the development of obesity and related liver diseases by an integration analysis of omics study and biological analysis in vivo and in vitro. Meanwhile, inhibitors were applied to investigate the mechanism of BDE-47-induced toxicity. Taken together, our results indicated that BDE-47 exposure could accelerate the development of obesity and aggravate the progression of fatty liver in obese mice via causing oxidative stress. This study may shed a light for an explanation for the worldwide prevalence of obesity and related liver diseases. Furthermore, this work reflects the potential of omics study and biological methods for toxicity assessment of environmental pollutants on human health. It would be helpful for the clinical diagnose and treatment.

Thesis (Ph.D.)--Indiana University, School of Public Environmental Affairs, 2005.
Title from PDF t.p. (viewed Dec. 2, 2008). Source: Dissertation Abstracts International, Volume: 66-02, Section: B, page: 0785. Chair: Ronald A. Hites.

The chemical contamination of sea turtles is an emerging area of conservation research. Chemicals, such as persistent organic pollutants (POPs) and heavy metals, have a wide range of harmful effects on animals and humans and are beginning to be reported in sea turtle populations around the world. However, prior to the present study, research on chemical contamination in sea turtles had generally been limited to studies on deceased animals. Furthermore, the analytical methods used in these studies had limited sensitivity and reported small numbers of compounds. The main objectives of this thesis were therefore to further develop methods for measuring POPs in sea turtles and to systematically investigate some of the important aspects of accumulation and transfer of POPs and heavy metals in the green sea turtle, Chelonia mydas. Gas chromatography with electron capture detection (GC-ECD) has generally been used to analyse POPs in sea turtle studies. However, GC-ECD relies on relative retention time for identification and can therefore not distinguish between co-eluting compounds. Furthermore, the limit of detection is relatively high (> 1 ng g-1) and these methods are therefore often unable to detect POPs in low trophic level organisms. More recent methods combining GC-ECD and gas chromatography with mass spectrometry (GC-MS) have reported a large number of POPs in sea turtles at trace concentrations. However, these methods required multiple injections of each sample into a complex arrangement of multiple gas chromatographs. This can only be replicated in well equipped and highly funded laboratories. It was therefore the first objective of this thesis to develop an equally accurate and sensitive method requiring a single injection of each sample onto a simple instrument setup. A method using gas chromatography with coupled mass spectrometry (GC-MS/MS) was developed on a Varian 3800 gas chromatograph fitted with a Saturn 2200 mass spectrometer and a 1079 programmable temperature vapourising (PTV) injector. Using calibrants and mass-labelled internal standard and recovery solutions obtained from the National Institute of Standards and Technology (NIST), South Carolina, USA, a GC-MS/MS method was established for 83 polyclorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs) and 19 polybrominated diphenyl ethers i i (PBDEs). Sample preparation was modified from previous studies and involved accelerated solvent extraction with dichloromethane, followed by gel permeation chromatography and Florisil clean-up procedures. Recoveries were generally > 60% and standard reference materials were reported to within 60 and 70% of the reference and certified values, respectively. The coefficients of variation of pooled samples were < 20%, although generally < 5%, and the limit of detection ranged from 5 to 35 pg g-1. This method therefore provided an accurate way of measuring a large number of POPs at trace concentrations in C. mydas. This method was then used to investigate a number of important accumulation and transfer aspects of chemical contamination in C. mydas. The earliest studies on chemical contamination in sea turtles sampled tissue from dead and stranded animals. However, it is of more interest to investigate the contamination of living sea turtle populations. Blood and carapace sampling have increasingly been used as non-lethal methods for analysing POPs and metals in sea turtles. However, there was very little information on how well blood and carapace samples represented the chemical contamination of internal tissues. To address this issue, blood, carapace, liver, kidney and muscle samples from 16 C. mydas that died at the Sea World Sea Turtle Rehabilitation Program were analysed for POPs and heavy metals. Heavy metal and POP levels in the blood and carapace were significantly correlated with internal tissue concentrations. Furthermore, these relationships were not affected by sex or age. While it must be considered that these C. mydas were in rehabilitation, blood and carapace samples are good predictors of the internal contamination of C. mydas. This information therefore provides scientists with reliable non-lethal methods for estimating chemical contamination in living sea turtle populations. Information on the accumulation of chemical contaminants in sea turtles was also limited prior to this study. The biology of sea turtles indicates that chemicals may accumulate through feeding and/or maternal transfer during vitellogenesis. The present study investigated the chemical contamination of C. mydas from different foraging areas. Satellite telemetry tracked the movement of three C. mydas nesting at Ma’Daerah, Peninsular Malaysia to three different foraging areas in Southeast Asia. Furthermore, the egg chemical contamination profiles of the C. mydas from these different foraging areas were significantly different. This suggested the use of ii i multivariate contaminant analysis to assess the variation of foraging area locations of a nesting C. mydas population. The use of contamination profiles to assess foraging ground variation in a nesting population was further supported by chemical analysis of eggs from 11 C. mydas nesting at Ma’Daerah, Peninsular Malaysia. The egg POP contamination profiles from the 11 turtles were separated into six groups. This indicated that these C. mydas nesting at Ma’Daerah may have migrated from six distinct foraging areas. However, investigation into the variation in chemical profiles of C. mydas from the same foraging areas must be investigated before this concept can be validated. There are a number of factors such as age, sex and specific foraging range that may lead to variations in C. mydas contamination from the same foraging area. The accumulation of POPs in C. mydas via maternal transfer to eggs and hatchlings was also investigated in the present study. Maternal blood, eggs and hatchling blood were collected from the 11 C. mydas nesting at Ma’Daerah. There were significant correlations in POP concentrations between maternal blood and eggs, indicating transfer of these chemicals to eggs during vitellogenesis. These results also indicated that egg sampling could be used as a relatively non-invasive method for determining POPs in adult female C. mydas. There were also significant correlations in POP concentrations between eggs and hatchling blood, indicating further transfer of these chemicals to hatchlings during development. Furthermore, as egg POP concentration increased the mass:length ratio of hatchlings decreased. This indicated a subtle influence of POPs on the development of C. mydas hatchlings that may compromise the duration of offshore dispersal and affect predator avoidance. The implications of chemical contamination on the conservation of C. mydas populations and on human health in communities that consume sea turtle eggs were investigated in Peninsular Malaysia. A sample of 55 C. mydas eggs was purchased from markets on the east coast of Peninsular Malaysia. According to the vendors, the eggs had been collected from sites ranging from adjacent beaches to thousands of kilometres away in Borneo Malaysia. The concentrations of POPs and metals in the eggs were variable among nesting areas and markets. A screening risk assessment indicated that the reported arsenic concentrations posed a relatively high risk of iv disruption to embryonic development. Furthermore, the large number of compounds detected was thought to increase the risks to embryonic development of C. mydas eggs. The concentrations of coplanar PCBs also posed a considerable risk to human health, with the consumption of a single C. mydas egg estimated to represent 3-300 times the acceptable daily intake (ADI) of these compounds. The large number of compounds detected was also expected to further contribute to the health risks of consuming C. mydas eggs. Incidentally, the human health risks associated with consuming C. mydas eggs may contribute to the conservation of this species in Southeast Asia. Public awareness campaigns highlighting the dangers associated with consuming C. mydas eggs could reduce the collection of eggs ..
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Antarctic seabirds including Adelie penguins (Pygoscelis adeliae), south polar skuas (Catharacta maccormicki), southern giant petrels (Macronectes gigantus) are high trophic level predators that accumulate persistent organic pollutants (POPs) present in the food webs in which they forage. Little is known about the levels of POPs in some Antarctic organisms (e.g. southern giant petrels), as well as the long-term trends of POPs in the Antarctic ecosystem. Samples from all three seabird species were collected post mortem, including eggs, from the Western Antarctic Peninsula (WAP) and in the Ross Sea throughout the austral summer breeding seasons of 2004--2006. The samples were analyzed for C and N stable isotopes and POPs including organochlorine pesticides, polychlorinated biphenyls (PCBs), and brominated diphenyl ethers (BDEs). The objectives of this study were to: (1) evaluate the long-term trends of POP residues in Adelie penguins, (2) compare POP levels within livers of the three seabird species based on migratory patterns and trophic level using stable isotope analysis of delta15N and delta13C, and (3) demonstrate POPs can be used as tracers of Antarctic seabird ecology. POPs in Antarctic biota were first evaluated using Adelie penguin tissues and a long-term analysis including data from the current study showed SigmaDDT has not declined in WAP penguins for more than 30 years. Indeed, the presence of p,p'-DDT in these birds indicates that there is a current source of DDT to the WAP marine food web, and both measurements and calculations suggest that this source of DDT is related to climate driven environmental change in the region. A more broad analysis including all three seabird species showed SigmaPCBs, SigmaDDTs, Sigmachlordanes and mirex are 3--100 times higher in migratory seabird livers than the endemic penguins, while hexachlorobenzene (HCB) exhibits no difference in concentration between the three seabird species. Model predictions compared to measured output of delta13C and delta13N indicate a stronger correlation between delta13C and less volatile POP concentrations demonstrating the heavy influence of winter migration on the contaminant loads of seabirds that breed in Antarctica. Finally, discrepancies in POP ratios between migratory and endemic seabird eggs and fat in combination with stable isotope signatures gave insight into seabird evolutionary breeding strategies. For example, the relative abundance of SigmaPCBs was highest in south polar skua eggs and endogenous lipid input into skua eggs was estimated at >79% by examining discrepancies in contaminant ratios. The combined stable isotope and contaminant data indicate that south polar skuas and southern giant petrels employee different combinations of income and capital breeding strategies.

The thesis reports the synthesis of magnetic Mn-based nanocatalysts by different hydrothermal methods and their application in the oxidative reaction of aqueous phenol solutions for wastewater treatment. It was found that all the catalysts present high activity in peroxymonosulfate (PMS, Oxone) activation for the decomposition of phenol and good magnetic performance in separation. This research makes good contributions to materials synthesis and catalytic oxidation of organic pollutants in water.

Advanced oxidation processes have been extensively studied for wastewater purification in past years. Nanocarbons demonstrated robust catalytic activity in activation of sulfate oxidants for toxic organics degradation, meanwhile; completely avoiding the secondary contamination. This research was dedicated to the investigation on the relationship between the structure modification of nanocarbon materials and the catalytic activity and stability. The findings provided a novel and feasible way to address global water pollution issues.

I contaminanti organici persistenti costituiscono un gruppo di sostanze chimiche artificiali strutturalmente tra loro diverse e caratterizzate, quale elemento comune, da un’elevata bio-persistenza e dalla capacità di essere trasportate per lunghe distanze su scala planetaria, lontano dal luogo originario di emissione nell’ambiente. A questa classe di sostanze chimiche appartengono, tra gli altri, i bifenili poli-clorurati, i pesticidi organo-clorurati, tra cui il DDT e i suoi metaboliti, e altri prodotti chimici come le dibenzo-p-diossine e i dibenzo-furani policlorurati. Queste sostanze chimiche sono ormai ampiamente distribuite nell'ambiente, in quanto alcuni di loro sono stati a lungo impiegati in agricoltura e nella sanità pubblica come pesticidi (il DDT e gli altri insetticidi clorurati), altri come prodotti chimici industriali (i bifenili poli–clorurati) e altri sono inevitabili sottoprodotti di processi industriali (le dibenzo-p-diossine e i dibenzo–furani policlorurati). Per le loro caratteristiche tossicologiche, queste sostanze chimiche possono essere fonte di rischio per la salute umana. In Italia si è fatto largo uso di insetticidi della famiglia organo clorurata (DDT e prodotti simili) dagli anni ‘40 agli anni ‘70 del 1900, soprattutto per fini di salute pubblica, per l’eradicazione di vettori (zanzare) della malaria e dei PCB, prodotti in Italia per il settore manifatturiero (produzione di dispositivi elettrici e termici), nella produzione di energia (uso di trasformatori e condensatori) e come materiali industriali in diversi comparti. Ciò nonostante, le informazioni sui livelli di esposizione della popolazione generale rimangono limitate. Questo studio si è proposto di misurare i livelli di alcuni insetticidi organo-clorurati e dei PCB nella popolazione generale italiana in tre luoghi diversi: Novafeltria (un paese del Centro Italia), Pavia (una città di medie dimensioni) e Milano (la seconda città più grande in Italia) e ad esplorare la relazione del loro accumulo nella popolazione con i luoghi di residenza, il sesso, l’età e la costituzione individuale. Per misurare le concentrazioni di PCB, i campioni di sangue sono stati raccolti campioni di sangue da 372 soggetti che hanno fornito il consenso informato e per misurare gli insetticidi organo-clorurati sono stati raccolti i campioni da 137 soggetti. Nel siero sono stati misurati 36 congeneri dei PCB e 8 insetticidi organo-clorurati mediante gas-cromatografia-spettrometria di massa. Per normalizzare le concentrazioni dei PCB e degli insetticidi organo-clorurati alle concentrazioni totali di lipidi nel sangue (una tecnica comunemente impiegata per tener conto del carattere lipofilico dei composti), sono stati misurate le concentrazioni sieriche di trigliceridi e colesterolo totale mediante tecniche standard di chimica clinica. Le informazioni personali quali il sesso, l'età, l'altezza e il peso, le abitudini alimentari, l'istruzione, la residenza e l'occupazione le informazioni sono state raccolte attraverso un questionario. Sono state impiegate analisi statistiche per evidenziare eventuali relazioni dei livelli degli analiti con caratteristiche dei soggetti indagati quali la residenza, l’età, il sesso e l’indice di massa corporea. Le concentrazioni degli analiti sono state indagate in termini sintetici per la popolazione complessiva dei 3 siti, e separatamente per i singoli siti, per sesso, per età e per le categorie di BMI. I PCB congeneri 138, 153 e 180 sono stati quelli più frequentemente rilevati nei campioni e sono risultati quelli maggioritari nel concorrere alla dose totale di PCB. Il PCB 153 ha il più alto livello medio in ciascun sito. Il livello totale di PCB differisce in modo significativo tra questi siti (p < 0,0001) con concentrazioni mediane di 837, 1355 e 2062 pmol/g di lipidi, rispettivamente a Novafeltria, a Pavia e in Milano. Non sono state dimostrate differenze nella distribuzione dei livelli di PCB totali tra i due sessi. La somma dei PCB diossino-simili differiva in modo significativo (p < 0,0001) tra i siti (media 111 e 167 pmol/g di lipidi, rispettivamente) e tra i due sessi a Novafeltria e a Pavia (p = 0,011 e 0,009, rispettivamente). I PCB 138, 153, 170 e 180 differivano in modo significativo tra i luoghi di residenza (p < 0,0001), con valori più elevati nella popolazione di Milano. In generale, nella popolazione totale esaminata i livelli dei PCB totali e dei congeneri 138, 153, 156, 170 e 180 correlano positivamente con l'età (coefficienti r di correlazione compresi tra 0,320 e 0,569, p < 0,0001). A Novafeltria i coefficienti r risultano compresi tra 0,545 e 0,670 e tra 0,516 e 0,666 a Pavia. A Milano, i coefficienti r per le correlazioni con età sono risultati compresi tra 0,327 e 0,417 per i PCB totali e per i congeneri 138, 153 e 180. Ad eccezione del PCB 170 non è stata osservata alcuna differenza significativa nella distribuzione dei più abbondanti congeneri di PCB e PCB totali tra le diverse categorie di BMI (individui ‘più o meno grassi’). Tra gli insetticidi organo-clorurati, il p,p'-DDE e l’HCB contribuiscono in misura magiore al carico corporeo totale per la classe di composti. I loro livelli differiscono in modo significativo tra le tre città, con un trend di Milano > Novafeltria > Pavia (p < 0,0001). Considerando l’intero campione, le femmine hanno concentrazioni significativamente più alte di HCB e p,p'-DDE rispetto ai maschi. Le concentrazioni di HCB sono significativamente più alte nelle femmine rispetto ai maschi di Milano (p = 0,029). Abbiamo osservato correlazioni positive tra la concentrazione di p,p'-DDE e HCB e l’età solo nei soggetti di Novafeltria (r = 0,468, p = 0,004). Considerando l’intera popolazione studiata, le concentrazioni dell’insetticida organo clorurati totali differiscono in modo significativo tra le categorie di BMI (p = 0,018). Abbiamo misurato il pattern dei principali congeneri dei PCB e degli insetticidi organo-clorurati in una campione abbastanza esteso della popolazione italiana. In generale il nostro studio fornisce informazioni sui livelli di esposizione a PCB e ad insetticidi organo-clorurati e fornisce indicazioni per ulteriori indagini.
Persistent Organic Pollutants is a group of structurally diverse man-made chemicals characterized by a high bio-persistence and the ability to travel a long distance on the planetary scale. This class of chemicals includes polychlorinated biphenyls, organochlorinated pesticides such as DDT and its metabolites and other chemicals such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans. These chemicals are widely distributed in the environment as some of them have long been employed in agriculture and in public health as pesticides, others as industrial chemicals and others are unavoidable by-products of industrial processes. These chemicals can be a source of health risk to human. Despite extensive use of OCPs such DDT in Italy in the 1940s to 1970s especially for public health control of malaria mosquitoes and PCBs in industry, in energy production and in industrial commodities, information on their exposure levels among the general population is limited. This study aims at determining the levels of OCPs and of PCB congeners among the residents from Italians living in three different places: Novafeltria (a village in Central Italy), Pavia (a mid-sized town) and Milan (the second-largest city in Italy) and at exploring the relationship with places of residence, gender, age and individual body size of their accumulation in the population. To measure PCBs concentrations, blood samples were collected from 372 consented subjects whereas to measure OCPs blood samples were collected from 137 subjects. Thirty six PCB congeners and eight OCPs were measured in blood serum by gas-chromatography-mass spectrometry. To normalize PCBs and OCPs concentrations to total blood lipid concentrations (a commonly employed technique to take into account the lipophilic character of the compounds), serum concentrations of triglycerides and total cholesterol were measured by standard clinical chemistry techniques. Personal information such as gender, age, height and weight, dietary habits, education, residence and occupation information were collected through a questionnaire. Statistical analyses were employed to highlight variation in analytes levels with respects to residence, age, gender and body mass index. The analytes concentrations were summarized for the overall population of three sites and separately for the individual sites, for gender, for age groups and for BMI categories. The PCB congeners 138, 153 and 180 were the most frequently detected in overall population sample and were the major contributors of total PCB burden. PCB 153 had the highest median level in each site. Total PCB level differed significantly between the study sites (p < 0.0001) with median concentrations of 837, 1355 and 2062 pmol/g lipid, respectively in Novafeltria, Pavia and Milan. No evidence was found for the difference in distribution of total PCB levels by genders. Total DL–PCB differed significantly (p < 0.0001) between the sites (median 110, 51 and 167 pmol/g lipid, respectively) and genders of Novafeltria and Pavia (p = 0.011 and 0.009, respectively). PCB 138, 153, 170 and 180 differed significantly between the sites (p < 0.0001) with higher values in Milan population. In overall population total PCB, PCB 138, 153, 156, 170 and 180 correlated positively with age (r for linear correlations range between 0.320–0.569, p < 0.0001). In Novafeltria the r correlations range between 0.545–0.670 and 0.516–0.666 in Pavia. In Milan, r correlations with age range between 0.327–0.417 for total PCB, congener 138, 153 and 180. With exception of PCB 170 there was no evidence of significant difference in distribution of most abundant PCB congeners and total PCB across the BMI categories. Among the OCPs, p,p'-DDE and HCB were the most abundant and major contributors of total OCP concentration. Their levels differed significantly between the three towns with a trend Milan > Novafeltria > Pavia (p < 0.0001). Females had significantly higher concentrations of HCB and p,p'-DDE than males in overall population sample. HCB concentrations were significantly higher in females than in males of Milan (p = 0.029). We observed positive correlations of p,p'-DDE and HCB with age in Novafeltria subjects (r = 0.468, p = 0.004). Total OCP concentrations differed significantly across BMI categories (p = 0.018) in overall population. We have demonstrated a pattern of distribution of the levels of the main PCB congeners and OCPs in a fairly large population in Italy. Generally our study provides information on PCBs and OCPs exposure among the Italian general population and provides indications for further investigations.

Presented is a study of persistent organic pollutants in Australian sewage sludge, focusing on environmental monitoring and a sewage sludge land application human health risk contaminated with these compounds. The chemicals of concern were: • Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and