<p>Persistent organic pollutants (POPs) is a group of chemicals that are toxic, undergo long-range transport and accumulate in biota. Due to their persistency the distribution and recirculation in the environment often continues for a long period of time. Thereby they appear virtually everywhere within the biosphere, and poses a toxic stress to living organisms. In this thesis, attempts are made to contribute to the understanding of factors that influence the distribution of POPs with focus on processes in the marine environment. The bioavailability and the spatial distribution are central topics for the environmental risk management of POPs. In order to study these topics, various field studies were undertaken. To determine the bioavailable fraction of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated naphthalenes (PCNs), and polychlorinated biphenyls (PCBs) the aqueous dissolved phase were sampled and analysed. In the same samples, we also measured how much of these POPs were associated with suspended particles. Different models, which predicted the phase distribution of these POPs, were then evaluated. It was found that important water characteristics, which influenced the solid-water phase distribution of POPs, were particulate organic matter (POM), particulate soot (PSC), and dissolved organic matter (DOM). The bioavailable dissolved POP-phase in the water was lower when these sorbing phases were present. Furthermore, sediments were sampled and the spatial distribution of the POPs was examined. The results showed that the concentration of PCDD/Fs, and PCNs were better described using PSC- than using POM-content of the sediment. In parallel with these field studies, we synthesized knowledge of the processes affecting the distribution of POPs in a multimedia mass balance model. This model predicted concentrations of PCDD/Fs throughout our study area, the Grenlandsfjords in Norway, within factors of ten. This makes the model capable to validate the effect of suitable remedial actions in order to decrease the exposure of these POPs to biota in the Grenlandsfjords which was the aim of the project. Also, to evaluate the influence of eutrophication on the marine occurrence PCB data from the US Musselwatch and Benthic Surveillance Programs are examined in this thesis. The dry weight based concentrations of PCB in bivalves were found to correlate positively to the organic matter content of nearby sediments, and organic matter based concentrations of PCB in sediments were negatively correlated to the organic matter content of the sediment.</p>

O acúmulo de poluentes orgânicos persistentes é um dos principais problemas de contaminação do meio ambiente em todo o mundo. As atividades industriais e os avanços tecnológicos na maioria dos setores de produção contribuem com a crescente liberação de compostos poluentes, altamente tóxicos, biocumulativos e resistentes à degradação física, química, fotolítica e biológica. Esses poluentes são o resultado do uso indevido de pesticidas de um modo geral, da subprodução não planejada de sintéticos tóxicos como dioxinas policloradas e de uma lista enorme de atividades que promovem a combustão incompleta da matéria orgânica e despejam no ambiente uma vasta quantidade de hidrocarbonetos aromáticos persistentes. A biorremediação é uma estratégia biotecnológica que vem lançar luz sobre as técnicas de revitalização de sítios contaminados. É baseada na utilização de microorganismos, ou suas enzimas, para reduzir ou eliminar perigos ambientais contaminantes em substâncias inertes, CO2 e água. As oxigenases são uma classe de enzimas amplamente estudadas por suas propriedades catalíticas únicas, sendo a clorocatecol 1,2- dioxigenase de Pseudomonas putida um interessante alvo biotecnológico para a biorremediação devido a sua ampla especificidade a substratos aromáticos, aromáticos halogenados e dialogenados altamente poluentes, biocumulativos e carcinogênicos. Nesse trabalho, o protocolo de expressão heteróloga em E. coli foi implementado em nosso laboratório e a purificação realizada em coluna de afinidade através do uso de resina de quitina. Os cristais de cor marrom avermelhado da enzima clorocatecol 1,2-dioxigenase Pseudomonas putida foram obtidos na presença de polietilenogligol e acetato de magnésio durante o período de 10 dias, utilizando-se a técnica de difusão de vapor em gota sentada. A estrutura cristalográfica da enzima Pp 1,2-CCD foi determinada através da utilização da técnica MR-SAD, utilizando átomos de ferro, cofator da proteína, como agentes espalhadores e as coordenadas da enzima 3-clorocatecol 1,2-dioxigenase de Rhodococcus opacus como modelo de busca. O modelo final, contendo 3 moléculas na unidade assimétrica foi refinado a 3.4 Å de resolução. A enzima se enovela na forma dimérica (Fe3+)2, e apresenta de um modo geral, dois domínios catalíticos compostos de fitas-beta e uma região de loops e um domínio de ligação composto por hélices formando um túnel hidrofóbico. Como a primeira clorocatecol de bactérias gram-negativa a ser descrita para essa classe de enzimas, será possível investigar as diferenças conformacionais que levam aos mecanismos de catálise, amplo a diversos substratos, e avaliar características de seu funcionamento e ativação, como uma importante ferramenta para validação do papel desta proteína dentro do processo de biorremediação. / Accumulation of persistent organic pollutants is one of the most important environmental problems worldwide. Industrial activities and technological advances contribute to the spread of pollutants, highly toxic, bioaccumulative, and resistant to physical, chemical, photolytic and biological degradation. The persistent organic pollutants are consequence of the inappropriate use of pesticides, the production of toxic synthetic compounds such as polychlorinated biphenyls and a large list of activities promote incomplete combustion of which organic matter and release a large amount of persistent aromatic hydrocarbons to the environment. Bioremediation is a biotechnogical strategy that has shed light on revitalization techniques of contaminated sites. It is based on the application of microorganisms, or their enzymes, to eliminate or reduce environmental contaminants into inert substances, CO2 and water. The oxygenases are a class of largely studied enzymes due to their catalytic properties, being chlorocatechol 1,2-dioxygenase from Pseudomonas putida an interesting biotechnological target for bioremediation due to its specificity to a broad spectrum of highly polluted aromatic substrates. In the present work, heterologous expression protocol has been implemented in our laboratory and purification was performed by using affinity column in chitin resin. Brown-reddish crystals of chlorocatechol 1,2-dioxygenase from Pseudomonas putida were obtained in presence of polyethylene glycol (PEG) and magnesium acetate after 10 days, by utilizing vapor diffusion techniques in sitting drops. The crystallographic structure of Pp 1,2-CCD has been solved by MR-SAD technique, using iron atoms, the enzyme cofactor, as scattering centers and the coordinates of 3- chlorocatechol 1,2-dioxygenase of Rhodococcus opacus as the search model. The final model, containing three molecules in the asymmetric unit, has been refined up to 3.4 Å resolution. The enzyme folds in the dimeric form (Fe3+)2, and shows two catalytic domains composed of -strands and a loop region, and a helical domain that pack together forming a hydrophobic channel. As being the first member of the chlorocatechol dioxygenase family of enzymes from a gram-negative bacteria to be solved, it will be possible to explore the crystallographic structure of chlorocatechol 1,2- dioxygenase from Pseudomonas putida in order to investigate the conformational differences that explain its mechanism of action, on a broad spectrum of substrates, and evaluate the functional features, as an important tool to validate the role of this enzyme in the bioremediation process.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-09-18T13:59:23Z No. of bitstreams: 1 2017 - Verona Borges Ferreira.pdf: 1252759 bytes, checksum: 291a4f24b8d135e118f8e80afed31cfd (MD5) / Made available in DSpace on 2017-09-18T13:59:23Z (GMT). No. of bitstreams: 1 2017 - Verona Borges Ferreira.pdf: 1252759 bytes, checksum: 291a4f24b8d135e118f8e80afed31cfd (MD5) Previous issue date: 2017-02-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Brazil is among the world?s largest fish producers, and the state of Rio de Janeiro is one of the main responsible for this production. In addition, there is a substantial increase in fish consumption which is associated to its functional and nutritional properties, such as its lipid profile. Today the hydrographic bays of Rio de Janeiro suffer the impacts of excessive use of toxic substances, such as Organoclorine Pesticides (OCPs), which has a characteristic lipophilicity and tend to accumulate in adipose tissue of organisms. As a consequence, this may pose risk to consumers of fish from polluted environments. The human exposure to these pollutants is highly related to health problems, such as cancer, immunity diseases and endocrine disruptions. Thus, the present study aims at investigating the occurence of OCPs in sardine (Sardinella brasiliensis), whitemouth croaker (Micropogonias furnieri) and mullet (Mugil liza) from Guanabara Bay, located in the state of Rio de Janeiro, and also to estimate the OCPs intake through fish consumption. The analyses were carried out at the Laboratory of de Radioisotopes Eduardo Penna Franca at UFRJ. The analitical steps included sohxlet extration, purification and subsequent injection in a Gas Chromatography system coupled to a Mass Spectrometer on Negative Chemical Ionization mode (GC/MS/ENCI) to determine the OCPs concentrations. The estimative of the toxic compound intake was performed based on the obtained data for OCP in fish samples, the fish intake of the brazilian population, andavailable data of Acceptable Daily Intake (ADI) for each investigated pesticide. All samples had at least one OCP. Metoxichlor had the highest concentration for the three studied species. There was significant difference between the species concerning the concentration of o,p?-DDD and o,p?-DDT. These DDT metabolites were found at higher concentration in sardine samples in comparison to croaker and mullet ones. However, there was no significant difference between the species in relation to ?OCP. It was evidenced the greater proportion of DDE among the DDT metabolites which suggests the past use of this pesticide. Results for ?-HCH isomer indicate the contamination by the use of Lindane instead of the technical HCH mixture. There was no significant difference among the contamination of the three studied species in regard to sample's acquisition locations, showing that the locality does not influence the content of OCPs in fish, probably due the species behavior which travel big distances along the brazilian coast throughout their life cycle. No sample exceeded the maximum residue limit stipulated for OCPs at both national or international level. Based on the estimated intake data no species exceeded the toxicological safety parameter. Thus, the three studied fish species can be considered safe for human consumptiom in regard to OCPs exposure / O Brasil est? entre os maiores produtores mundiais de pescado, sendo o estado do Rio de Janeiro um dos principais respons?veis por essa produ??o. Al?m disso, existe um aumento substancial do consumo de peixes, que est? associado ? suas propriedades nutricionais e funcionais, como o seu excelente perfil lip?dico. As bacias hidrogr?ficas do Rio de Janeiro sofrem hoje os impactos do uso excessivo de subst?ncias t?xicas, como os Pesticidas Organoclorados (OCPs), que devido ? caracter?stica lipof?lica, tendem a se acumular no tecido adiposo de organismos aqu?ticos, o que pode representar um risco a sa?de de quem consome pescado oriundos de ambientes contaminados. Por sua vez, a exposi??o humana a estes poluentes est? altamente relacionada a problemas de sa?de, tais como o surgimento de c?ncer, problemas de imunidade e interfer?ncias end?crinas. Desta forma, o presente estudo tem por objetivo investigar a ocorr?ncia de OCPs em amostras de sardinha-verdadeira (Sardinella brasiliensis), corvina (Micropogonias furnieri) e tainha (Mugil liza) capturados na Ba?a de Guanabara, localizada no estado do Rio de Janeiro, assim como estimar a ingest?o de OCPs por meio do consumo de pescado. As an?lises foram realizadas no Laborat?rio de Radiois?topos Eduardo Penna Franca da UFRJ, atrav?s de sua extra??o, purifica??o e posterior inje??o em um sistema de Cromatografia Gasosa acoplada a um Espectr?metro de Massa por ioniza??o qu?mica negativa (CG/EM/NCI) para determinar as concentra??es de OCPs. Para estimar a ingest?o desses compostos t?xicos foram utilizados os dados de contamina??o das amostras, consumo do pescado pela popula??o brasileira, assim como os dados de Ingest?o Di?ria Aceit?vel (IDA) para cada contaminante. Todas as amostras investigadas estavam contaminadas com pelo menos um OCP, o Metoxicloro foi o pesticida encontrado em maior concentra??o nas tr?s esp?cies estudadas e houve diferen?a significativa entre as esp?cies em rela??o a concentra??o de o,p?-DDD e o,p?-DDT, estes metab?litos do DDT foram encontrados em maior concentra??o nas amostras de sardinha-verdadeira em rela??o as amostras de corvina e tainha, entretanto n?o houve diferen?a significativa entre as esp?cies em rela??o ao ?OCP. Ficou evidenciada a maior propor??o do DDE entre os metab?litos de DDT, n?o sugerindo o uso recente deste pesticida, e do is?mero ?-HCH entre os demais is?meros de HCH, evidenciando a contamina??o pelo uso de Lindano em rela??o ao HCH t?cnico. N?o houve diferen?a significativa entre a contamina??o das tr?s esp?cies com base nos diferentes pontos de coleta, demonstrando que a localidade de aquisi??o do pescado n?o influenciou no teor dessas subst?ncias, uma vez que estas esp?cies ao longo de seu ciclo de vida percorrem grandes dist?ncias pela costa brasileira. Nenhuma amostra excedeu os limites m?ximos de res?duo estipulados para esses contaminantes tanto a n?vel de regulamenta??o nacional quanto internacional. Com base nos dados de estimativa de ingest?o nenhuma esp?cie excedeu o par?metro toxicol?gico de seguran?a, sendo assim, as tr?s esp?cies estudadas s?o consideradas seguras para o consumo humano em rela??o a exposi??o a OCPs

<p>U okviru disertacije analizirano je prisustvo različitih postojanih zagađujućih<br />materija u abiotskim i biotskim uzorcima iz različitih regiona, uključujući i uzorke<br />zemlji&scaron;ta iz Novog Sada i okolnih naselja, i to zagađujuće materije organskog<br />(policiklične aromatične ugljovodonike, polihlorovane bifenile i organohlorne<br />pesticide) i neorganskog (te&scaron;ki elementi) porekla. Dobijeni rezultati uvr&scaron;teni su u<br />baze zajedno sa relevantnim podacima iz međunarodnih radova i na taj način<br />formirane su baze koje prevazilaze lokalne interese pojedinačnih istraživanja.<br />Primenom multivarijacionih metoda analize ovakvih baza utvrđen je stepen<br />zagađenosti ispitivanih uzoraka u odnosu na rezultate iz literature, a takođe je<br />razmatrana struktura formiranih multidimenzionalnih baza sa ciljem analize<br />raspodele postojanih zagađujućih jedinjenja u posmatranim matriksima i<br />identifikacije zajedničkih izvora zagađenja. Primenom različitih (matematičkih)<br />predtretmana podataka u bazama, a zatim njihovom analizom izabranim<br />multivarijacionim metodama, izvr&scaron;ena je procena uticaja predtretmana na<br />rezultate i mogućnosti njihove interpretacije, kao i ispitivanje zavisnosti između<br />posmatranih veličina i grupisanje uzoraka. Specifični ciljevi istraživanja su<br />omogućili da se:<br />- utvrde sličnosti i razlike pri kori&scaron;ćenju različitih načina izražavanja<br />analitičkih rezultata (apsolutne vrednosti koncentracije nasuprot relativnih<br />procentualnih udela, tzv. kompozicionih podataka) u okviru baza<br />podataka i pri izdvajanju informacija iz multidimenzionalnih baza<br />primenom multivarijacionih metoda,<br />- utvrdi uticaj različitih načina pripreme (obrade) podataka pre primene<br />multivarijacionih metoda radi dobijanja potpunijih informacija u cilju bolje<br />interpretacije podataka i smanjenja dimenzija baza podataka;<br />- ispitaju regionalne i vremenske razlike i/ili sličnosti između prisustva<br />posmatranih jedinjenja u abiotskim i biotskim matriksima radi uočavanja<br />dominantnih izvora zagađenja u određenim oblastima i vremenskim<br />periodima uz istovremenu karakterizaciju eksperimentalno ispitanih<br />uzoraka u odnosu na uzorke iz drugih regiona.<br />Postignuti rezultati predstavljaju jedinstvene rezultate primene multivarijacionih<br />metoda na bazama sastavljenim od podataka dobijenim u različitim<br />istraživanjima iz sveta o prisustvu postojanih zagađujućih materija u izabranim<br />abiotskim i biotskim uzorcima, doprinoseći tako analizi njihove op&scaron;te raspodele.</p> / <p>Presence of different pollutant classes of both organic (polycyclic aromatic<br />hydrocarbons, polychlorinated biphenyls and organochlorine pesticides) and<br />inorganic origin (heavy elements) were analysed in abiotic and biotic matrices<br />from various regions, including Novi Sad and its surrounding settlements.<br />Obtained results with available data published in the international articles were<br />included in the sets, forming the input matrices to be analysed by chemometric<br />techniques. Analysis of the created sets of data by multivariate approach was<br />performed due to determining pollution level of the investigated samples, as well<br />to elucidate the persistent pollutants distribution and profiles in the selected<br />matrices and to identify the common pollution sources.<br />Using different treatments of a set of input data, influence of these procedures to<br />results was assessed.<br />Specific aims of investigation were:<br />Determination of similarity and differences by using different ways of data<br />expression (apsolute values of concentrations as apposed to relative percent<br />fraction) in interpreration of multidimension data sets on the basis of multivariate<br />statistical approach<br />Determination of different processing of data before multivariate statistical<br />methods due to obtaining adequate information for interpretation of data and<br />reducing a set of original variables<br />Examination of regional and temporal differences and/or similarity among<br />presence of observed compounds in abiotic and biotic matrices due to<br />identification of dominant pollutant sources as well as comparative<br />characterisation of experimantally obtained data in relation to samples from<br />another regions worldwide.<br />Achieved results are unique examples of multivariate methods application on<br />large data sets with results on the occurance of pesistent organic compounds in<br />abiotic and biotic matrices obtained in different studies all over the world.</p>

Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in a number of common household and commercial products around the world. PBDEs enter the environment in a variety of ways, such as through emissions, leaching from end-of-life electronics in landfills, and incineration. While many countries have phased out the manufacturing of penta-, octa-, and deca-PBDEs or have banned the manufacture and use of these congeners altogether, these persistent organic pollutants (POPs) continue to be detected in humans and the environment. This study investigates spatial and temporal variations of selected PBDEs in the air of the Nandamojo watershed area in Costa Rica by comparing air concentrations of PBDEs in the dry winter vs. wet summer seasons and rural vs. urban areas and also investigates the impact of anthropogenic activities on air concentration of PBDEs. This study is significant to the field, because there are no baseline studies nor are there currently any monitoring programs to assess the environmental levels of PBDEs or other POPs for this region of the Guanacaste province. Baseline information is needed to track spatial and temporal trends as well as evaluate the effectiveness of control measures employed nationally and internationally. Samples obtained from passive air sampling devices were analyzed via GC/MS for a number of congeners. PBDE-47 and -99 were found to be the congeners present in greatest concentration in air samples from the Nandamojo watershed area. Air concentrations were estimated assuming an average sampler uptake rate of 3.5 m3/day and ranged as follows: ΣPBDE5 35.20-1549.25 pg/m3 over the entire study. The presence of PBDEs in remote and pristine environments indicates that PBDEs are now a global concern. This study suggests that the spatial and temporal distribution patterns observed are strongly related to anthropogenic activities and presence of a population similar to that observed in other studies. The presence of PBDEs has become a global issue and, as such, these results provide background information on air concentrations of PBDEs for use in a global-scale multimedia model. In order to monitor PBDEs globally, it is imperative to implement and/or expand surveillance programs internationally.

Polychlorinated Biphenyls (PCBs) are persistent organic pollutants known for their toxicological effects. Though industrial production of legacy PCBs was banned in 1977, they can still be measured in nearly all environmental matrices. The Chicago Sanitary and Ship Canal (CSSC) is lined with industry and the receiving waters to the Stickney Water Reclamation Plant, the World's largest waste water treatment plant and was therefore speculated to be a potential source of PCBs to the Greater Chicago Area. Surficial sediment samples were acquired along a 45 km stretch of the CSSC, from Kedzie Ave. to Lockport. PCBs in the bulk sediment were extracted using accelerated solvent extraction while PCBs in the porewater were extracted using solid phase micro extraction. The PCBs were identified and quantified using a variation on EPA method 1668C. A total of 176 individual and coeluting PCBs were identified and quantified in this study. The sum of PCB concentrations in the bulk sediment was found to range from 70 to 4970 ng/g dry wt. The sum of PCB concentrations in the freely dissolved sediment-porewater was found to range from 2 to 366 ng/L. The bulk and porewater concentrations were used to estimate an average mass flow rate of PCBs through the CSSC of 368 kg/y. The large mass flow rate of PCBs passing through the CSSC and the fact that the CSSC connects Lake Michigan to the Mississippi River suggest that continued monitoring of PCB concentrations are necessary to better understand the transport and fate of PCBs in and out of the Great Chicago Area.

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

Persistent organic pollutants (POPs) is a group of chemicals that are toxic, undergo long-range transport and accumulate in biota. Due to their persistency the distribution and recirculation in the environment often continues for a long period of time. Thereby they appear virtually everywhere within the biosphere, and poses a toxic stress to living organisms. In this thesis, attempts are made to contribute to the understanding of factors that influence the distribution of POPs with focus on processes in the marine environment. The bioavailability and the spatial distribution are central topics for the environmental risk management of POPs. In order to study these topics, various field studies were undertaken. To determine the bioavailable fraction of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated naphthalenes (PCNs), and polychlorinated biphenyls (PCBs) the aqueous dissolved phase were sampled and analysed. In the same samples, we also measured how much of these POPs were associated with suspended particles. Different models, which predicted the phase distribution of these POPs, were then evaluated. It was found that important water characteristics, which influenced the solid-water phase distribution of POPs, were particulate organic matter (POM), particulate soot (PSC), and dissolved organic matter (DOM). The bioavailable dissolved POP-phase in the water was lower when these sorbing phases were present. Furthermore, sediments were sampled and the spatial distribution of the POPs was examined. The results showed that the concentration of PCDD/Fs, and PCNs were better described using PSC- than using POM-content of the sediment. In parallel with these field studies, we synthesized knowledge of the processes affecting the distribution of POPs in a multimedia mass balance model. This model predicted concentrations of PCDD/Fs throughout our study area, the Grenlandsfjords in Norway, within factors of ten. This makes the model capable to validate the effect of suitable remedial actions in order to decrease the exposure of these POPs to biota in the Grenlandsfjords which was the aim of the project. Also, to evaluate the influence of eutrophication on the marine occurrence PCB data from the US Musselwatch and Benthic Surveillance Programs are examined in this thesis. The dry weight based concentrations of PCB in bivalves were found to correlate positively to the organic matter content of nearby sediments, and organic matter based concentrations of PCB in sediments were negatively correlated to the organic matter content of the sediment.

Polybrominated diphenyl ethers (PBDEs), flame retardants, have been applied to consumer goods, such as furniture, electrical devices, textiles, and appliances for decades. Due to their physico-chemical properties, PBDEs are semi-volatile and easily leach off the consumer good during aging, stress, or normal wear and tear of the good. Once airborne, they pose an environmental health threat because they can adsorb onto dust particles, soil, or other particulates that can be inhaled, ingested, or come into contact with the dermal layer. Additionally, PBDEs have a molecular structure similar to other persistent organic pollutants, such as polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins and furans. They are a health threat due to their endocrine-disrupting nature by affecting thyroid functioning, fertility, and child development. The purpose of the study is to measure selected PBDEs in a wastewater treatment plant (WWTP) that produces reclaimed water, such that a mass balance can be completed, and to compare this mass balance with theoretically expected concentrations. The mass balance includes the collection of samples from wastewater, sewage sludge, and air at points within the WWTP. The PBDEs examined are BDE-28, 47, 99, 100, 153, 154, and 183. The second part of the study will compare effluent concentrations to reclaimed water concentrations in order to examine the potential exposure (if any) of using reclaimed water. Influent concentration of mean (sum7)PBDE was found to be 49,117 pg/L and effluent concentration was 4,603 pg/L, illustrating a 91% removal rate of PBDEs during the wastewater treatment plant. Sludge samples contained the highest total concentrations of PBDEs with mean (sum7)PBDE ranging from 14.0 to 41.3 ug/kg dry weight. Air samples were highest at the post-aeration (248 pg/m3 mean (sum7)PBDE) step due to the use of highly oxygenated air assisting in the release and volatilization of the PBDEs. Sludge was found to carry the largest mass loading at 14.2 lb/day (sum7)PBDE. Of the total mass loading of PBDEs from the WWTP, sludge is responsible for 86.7%, followed by reclaimed water and effluent (11.7% and 1.6%, respectively). The mass loading from air was negligible with less than 0.01% contribution to the total mass loading. Whereas reclaimed water overall had higher PBDE congener mean concentrations than the effluent, the independent samples t-test found no statistically significant differences between the two groups. The results of this study can be used to improve the wastewater treatment process to reduce the impact of PBDEs being released into the environment by WWTPs, and to educate the public on utilizing reclaimed water in a safe and healthy manner.

Persistent organic pollutants (POPs) and adipose tissue hypoxia have been shown to independently affect adipocyte functions. The goals of this study were to (1) determine the effect of PCB-77, PCB-153, and DDE on the differentiation of human preadipocytes, and (2) investigate the cross-talk between PCB-77 and hypoxia in differentiated human adipocytes. First, human preadipocytes were exposed to PCB-77, PCB-153, or DDE during the entire 14-day differentiation period. We found no effect of low POP levels on lipid accumulation. Second, differentiated human adipocytes were exposed to a combination of PCB-77 and hypoxia. We demonstrated gene-specific cross-talk between PCB-77 and hypoxia, showing an additive effect of PCB-77 on VEGF, MCP-1, and adiponectin, as well as an inhibition of PCB-77-induced expression of CYP1A1 by hypoxia. This work has expanded our understanding of the role of POPs and hypoxia in differentiated human adipocytes.