A distribuição espacial e o histórico deposicional de poluentes orgânicos persistentes (POPs) em sedimentos foram avaliados no ecossistema marino-estuarino da Ilha do Marajó, Pará. Os pesticidas predominantes nos sedimentos da camada superficial foram os HCHs (<0,04 e 0,90 ng g-1) e DDTs (<0,02 - 2,72 ng g-1), em peso seco. PCBs e PBDEs não foram detectados. HCHs predominaram no Estuário do Rio Paracauari indicando uso recente provavelmente relacionado à atividade madeireira. DDTs foram detectados na Praia do Pesqueiro e nos testemunhos sedimentares (<0,02 - 12,31 ng g-1 peso seco) do Mercado, Fazenda e Paracauari. Os valores máximos de DDT ocorreram entre 1982 e 2008 e são associados com campanhas de saúde púbica. Há uma redução gradativa até o presente que coincide com a substituição do DDT por piretróides. A razão &#931;DDDs / &#931;DDEs, predominantemente < 1, indicou a ocorrência de processos decomposicionais aeróbicos. No geral, as condições ambientais não favorecem o acúmulo de pesticidas nos sedimentos, sendo que os valores estão abaixo do limite provável para causar efeitos adversos exceto para HCHs no Estuário do Rio Paracauari. O presente trabalho estabeleceu a distribuição de POPs na Ilha do Marajó e poderá contribuir para o processo de gestão costeira e ambiental da região. / The spatial distribution and depositional history of persistent organic pollutants (POPs) in sediments were evaluated in marino-estuarine ecosystem of Marajó Island, Pará. The predominant pesticides in sediments of the surface layer were HCHs (<0.04 and 0, 90 ng g-1) and DDTS (<0.02 to 2.72 ng g-1) by dry weight. PCBs and PBDEs weren\'t detected. HCHs predominated in Paracauari Estuary indicating recent use probably related to logging. DDTs were detected in Praia do Pesqueiro and sediment cores (<0.02 to 12.31 ng g-1 dry weight) Mercado, Fazenda and Paracauari. Maximum levels of DDT residues occurred between 1982 and 2008 and are associated with pubic health campaigns. There is a gradual reduction up to the present which coincides with the substitution of the DDTs by pyrethroids. The ratio &#931;DDDs / &#931;DDEs predominantly < 1 indicated the occurrence of decomposicional processes under aerobic conditions. Overall, the environmental conditions do not favor the accumulation of pesticides in sediments, and the values are below the threshold likely to cause adverse effects except for HCHs in Paracauari Estuary. This work established the distribution of POPs in Marajó Island and could contribute to the process of coastal and environmental management in the region.

Foi explorado o desenvolvimento de fotocatalisadores híbridos ZnO/Xerogel de carbono, visando aumentar a eficiência quântica do processo de degradação de poluentes orgânicos persistentes. Especificamente, foi estudada a preparação do híbrido ZnO-xerogel de carbono, sendo esta, a maior inovação tecnológica deste projeto, considerando que o efeito catalítico deste híbrido não foi estudado na literatura. O uso do xerogel de carbono na preparação do semicondutor-material carbonoso é justificado pela excelente condutividade elétrica, elevada área superficial e porosidade, além de sua estrutura porosa ser facilmente manipulada por modificações nos parâmetros de síntese. A escolha do tanino como precursor do xerogel visa à diminuição de custos e impactos ambientais, além de acrescentar valor à inovação tecnológica proposta. A influência do pH e rota de síntese foram avaliados, assim como a influência da temperatura de calcinação nas propriedades dos materiais. A espectroscopia por refletância difusa foi a técnica empregada para determinação da energia de gap das amostras. A morfologia, a análise elementar, a estrutura cristalina dos materiais, a estrutura química e a constituição dos materiais foram determinadas por microscopia eletrônica de varredura, espectrometria de energia dispersiva, difratometria de raios X, infravermelho e espectroscopia Raman, respectivamente. O balanço de cargas na superfície do material foi analisado pela metodologia do ponto de carga zero (PZC). A ação fotocatalítica do material foi avaliada através da decomposição de 4-clorofenol e bisfenol A, determinada através da espectroscopia no UV-Visível. Todos os materiais apresentam a estrutura cristalina hexagonal do óxido de zinco (wurtzita). Os materiais sem tanino em sua composição também apresentam a fase de hidroxicloreto de zinco mono-hidratado. Os difratogramas de raios-X e valores de bandgap obtidos confirmam a incorporação do carbono na estrutura cristalina do óxido de zinco. Os materiais produzidos via rota alcoólica apresentam menores valores de tamanho de cristalito e partícula, assim como um maior teor de grafite em sua composição e maior área superficial, enquanto que os materiais produzidos em solução aquosa apresentam menores valores de energia de gap. Todos os materiais apresentaram atividade fotocatalítica quando submetidos à radiação solar e visível, sendo que os materiais com proporções intermediárias entre xerogel de carbono e óxido de zinco se mostraram superiores para o processo de fotodegradação. Os materiais produzidos via alcoólica são superiores aos produzidos em solução aquosa, no que tange o processo de fotocatálise. Os valores máximos encontrados para a degradação de 4-clorofenol e bisfenol A foram de 88% e 78%, respectivamente, obtidos pelo material XZnC 3.0 (EtOH). A temperatura de calcinação e quantidade de hidróxido de potássio utilizados na síntese influenciam significativamente as propriedades dos materiais, de modo que as condições ótimas para a síntese dos materiais foram de calcinação em 300oC e 8 g de hidróxido de potássio utilizadas na síntese. O mecanismo de fotocatálise é fortemente influenciado pela geração de radicais hidroxilas e os materiais apresentam estabilidade para reciclo em processos industriais. / The development of ZnO/Carbon xerogel hybrid photocatalysts was studied, in order to increase the quantum efficiency of the degradation process of persistent organic pollutants. Specifically, the preparation of the ZnO-carbon xerogel hybrid was studied, being this the most significant technological innovation of this project, considering that the catalytic effect of this hybrid was not studied in the literature. The use of carbon xerogel in the preparation of the semiconductor-carbonaceous material is justified by its excellent electrical conductivity, high surface area and porosity, the latter being easily manipulated by modifications in the synthesis parameters. The choice of tannin as the precursor of the xerogel aims at reducing costs and environmental impacts, adding value to the proposed technological innovation. The influence of the pH and route of synthesis were evaluated, as well as the influence of the calcination temperature on the properties of the materials. Diffuse reflectance spectroscopy was the technique used to determine the gap energy of the samples. The morphology, elemental analysis, crystalline and chemical structure of the materials were determined by scanning electron microscopy, dispersive energy spectrometry, X-ray diffractometry, infrared and Raman spectroscopy, respectively. The charge balance on the material surface was analyzed by the point of zero charge methodology (PZC). The photocatalytic action of the material was evaluated by the decomposition of 4-chlorophenol and bisphenol A, determined by UV-Visible spectroscopy. All materials have the hexagonal crystalline structure of zinc oxide (wurtzite). The materials without tannin in their composition also present the zinc hydroxychloride monohydrate phase. The X-ray diffractograms and bandgap values obtained confirm the incorporation of the carbon in the crystalline structure of the zinc oxide. The materials produced via the alcohol route have lower values of crystallite and particle size, as well as a higher content of graphite in their composition and larger surface area, while the materials produced in aqueous solution have lower values of gap energy. All the materials presented photocatalytic activity when subjected to visible and solar radiation, and the materials with intermediate proportions between carbon xerogel and zinc oxide were superior for the photodegradation process. The materials produced via alcohol route are superior to those produced in aqueous solution, as far as the photocatalysis process is concerned. The maximum values found for the degradation of 4-chlorophenol and bisphenol A were 88% and 78%, respectively, obtained by the material XZnC 3.0 (EtOH). The calcination temperature and amount of potassium hydroxide used in the synthesis significantly influence the properties of the materials, so that the optimum conditions for the synthesis of the materials were calcination at 300 °C and 8 g of potassium hydroxide used in the synthesis. The mechanism of photocatalysis is strongly influenced by the generation of hydroxyl radicals and the materials present stability for recycling in industrial processes.

A vast number of sites that have been contaminated by industrial activities have been identified worldwide. Many such sites now pose serious risks to humans and the environment. Given the large number of contaminated sites there is a great need for efficient, cost-effective  remediation methods. Extensive research has therefore been focused on the development of such methods. However, the remediation of old industrial sites is challenging, for several reasons. One major  problem is that organic contaminants become increasingly strongly sequestered as they persist in the soil matrix for a long period of time. This process is often referred to as ‘aging’, and leads to decreasing availability of the contaminants, which also affects the remediation efficiency. In the work underlying this thesis, the influence of soil and contaminant properties on the efficiency of various physical and chemical soil remediation methods was investigated. The investigated contaminants were polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Briefly, the results show that as the size of soil particles decreases the contaminants become more strongly sorbed to the soil’s matrix, probably due to the accompanying increases in specific surface area. This affected the efficiency of the removal of organic pollutants by both a process based on solvent washing and processes based on chemical oxidation. The sorption strength is also affected by the hydrophobicity of the contaminants. However, for a number of the investigated PAHs their chemical reactivity was found to be of greater importance for the degradation efficiency. Further, the organic content of a soil is often regarded as the most important soil parameter for adsorption of hydrophobic compounds. In these studies the effect of this parameter was found to be particularly pronounced for the oxidation of low molecular weight PAHs, but larger PAHs were strongly adsorbed even at low levels of organic matter. However, for these PAHs the degradation efficiency was positively correlated to the amount of degraded organic matter, probably due to the organic matter being oxidized to smaller and less hydrophobic forms. The amount of organic matter in the soil had little effect on the removal efficiency obtained by the solvent-washing process. However, it had strong influence on the performance of a subsequent, granular activated carbon-based post-treatment of the washing liquid. In conclusion, the results in this thesis show that remediation of contaminated soils is a complex process, the efficiency of which will be affected by the soil matrix as well as the properties of the contaminants present at the site. However, by acquiring thorough knowledge of the parameters affecting the treatability of a soil it is possible to select appropriate remediation methods, and optimize them in terms of both remediation efficiency and costs for site- and contaminant-specific applications.

Background and objective: Major risk factors for congestive heart failure (CHF) are myocardial infarction, hypertension, diabetes, atrial fibrillation, smoking, left ventricular hypertrophy (LVH) and obesity. However, since these risk factors only explain part of the risk of CHF, we investigated whether persistent organic pollutants (POPs) might also play a role. Methods: In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, left ventricular ejection fraction, (EF), E/A-ratio and isovolumic relaxation time (IVRT), were determined by echocardiography and serum samples of 21 POPs were analyzed in serum measured by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS) in 998 subjects all aged 70 years. Results: In this cross-sectional analysis, high levels of several of the polychlorinated biphenyls (PCB congeners 99, 118, 105, 138, 153, and 180) and octachlorodibenzo-p-dioxin (OCDD) were significantly related to a decreased EF. Some POPs were also related to a decreased E/A-ratio (PCBs 206 and 209). All the results were adjusted for gender, hypertension, diabetes, smoking, LVH and BMI, and subjects with myocardial infarction or atrial fibrillation were excluded from the analysis. Conclusions: Circulating levels of POPs were related to impairments in both left ventricular systolic and diastolic function independently of major congestive heart failure risk factors, suggesting a possible role of POPs in heart failure.

<p>Reactive Black 5 and Procion Red MX 5B, an azo and anthraquinone dye repectively were decoulorized by mean of microorganisms growing on wood chips. The process consisted of three reactors, two anaerobic reactors and one aerobic reactor. The anaerobic process was used in order to make it possible to break the nitrogen bond of the azo group, (-N=N-) and the aerobic one to increase the possibility for the degradation of possible intermediates. After pumping wastewater through the system it was shown that mixtures or Reactive Black 5 and Procion Red MX 5B were efficiently decolourised at 50 mg/l as well as 200 mg/l of each of the dyes.</p><p><strong> </strong></p>

This thesis examines the air-soil and air-water gas exchange of persistent organic pollutants (POPs) with emphasis on organochlorine pesticides (OCPs). The current status of net exchange, factors which influence the exchange process, and different approaches used to estimate the surface exchange were explored. The net exchange of chemicals was evaluated using the fugacity approach, with the aid of chemical tracers (congener profiles of complex mixtures and enantiomer proportions of chiral chemicals) to infer current use vs. legacy sources to the atmosphere. DDT in southern Mexico was undergoing net deposition from air to soil. Occurrence of fresher DDT residues in the south was indicated by a higher proportion of p,p’-DDT relative to p,p’-DDE and racemic o,p’-DDT in air and soils. Congener profiles of toxaphene suggested soil emissions as the source to air. The influence of chemical aging on soil-air exchange and bioaccessibility was studied in a high organic soil. The use of nonexhaustive extraction with hydroxypropyl-beta-cyclodextrin (HPCD) to predict bioaccessibility was optimized for OCPs and polychlorinated biphenyls (PCBs). Reduced volatility of spiked chemicals correlated with reduced HPCD extractability for soil that had been aged under indoor and outdoor conditions for 730 d and infers volatility could be used as a surrogate for bioaccessibility. Measured soil-air partition coefficients (Ksa) were lower than those predicted from the Karickhoff relationship, which considers octanol as a surrogate for soil organic matter. The role of soil moisture, organic carbon, temperature, depth of soil surface horizon and dissolved organic carbon in the fate of organic contaminants in soil were assessed using chemical partitioning space maps. These maps allow instant visual prediction of the phase distribution and transport process of a chemical among the three major phases in soil; i.e., air, water and solid. Net volatilization of alpha-hexachlorocyclohexane from water to air was found in the southern Beaufort Sea using fugacity calculations and flux measurements. The influence of ice cover on volatilization was indicated by a winter-summer shift from racemic to nonracemic alpha-HCH in boundary layer air.

This thesis examines the air-soil and air-water gas exchange of persistent organic pollutants (POPs) with emphasis on organochlorine pesticides (OCPs). The current status of net exchange, factors which influence the exchange process, and different approaches used to estimate the surface exchange were explored. The net exchange of chemicals was evaluated using the fugacity approach, with the aid of chemical tracers (congener profiles of complex mixtures and enantiomer proportions of chiral chemicals) to infer current use vs. legacy sources to the atmosphere. DDT in southern Mexico was undergoing net deposition from air to soil. Occurrence of fresher DDT residues in the south was indicated by a higher proportion of p,p’-DDT relative to p,p’-DDE and racemic o,p’-DDT in air and soils. Congener profiles of toxaphene suggested soil emissions as the source to air. The influence of chemical aging on soil-air exchange and bioaccessibility was studied in a high organic soil. The use of nonexhaustive extraction with hydroxypropyl-beta-cyclodextrin (HPCD) to predict bioaccessibility was optimized for OCPs and polychlorinated biphenyls (PCBs). Reduced volatility of spiked chemicals correlated with reduced HPCD extractability for soil that had been aged under indoor and outdoor conditions for 730 d and infers volatility could be used as a surrogate for bioaccessibility. Measured soil-air partition coefficients (Ksa) were lower than those predicted from the Karickhoff relationship, which considers octanol as a surrogate for soil organic matter. The role of soil moisture, organic carbon, temperature, depth of soil surface horizon and dissolved organic carbon in the fate of organic contaminants in soil were assessed using chemical partitioning space maps. These maps allow instant visual prediction of the phase distribution and transport process of a chemical among the three major phases in soil; i.e., air, water and solid. Net volatilization of alpha-hexachlorocyclohexane from water to air was found in the southern Beaufort Sea using fugacity calculations and flux measurements. The influence of ice cover on volatilization was indicated by a winter-summer shift from racemic to nonracemic alpha-HCH in boundary layer air.

Water resources in South Africa are scarce, and should therefore be protected against pollutants, also from persistent organic pollutants (POPs). POPs are a global concern due to their ubiquitous presence, persistence and toxicity. This is emphasised by the Stockholm Convention on POPs, which aims at reducing and ultimately eliminating them. South Africa signed and ratified the treaty, and it became international law on 17 May 2004, but there is still a lack of information regarding POPs in South Africa. This study focussed on establishing the levels of POPs and other organic pollutants, which included various organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), dioxin-like compounds (DLCs), non-dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ether (PBDE). Sampling regions included the industrial cities – Cape Town, Richards Bay, Durban and Bloemfontein, and low-income, high density residential areas surrounding a wetland in Soweto/Lenasia and Botshabelo. Additionally, rivers flowing into neighbouring countries, rivers in the vicinity of paper and pulp producers and high altitude rivers were included. Sediment samples were firstly screened for the presence of DLCs by the H4IIE-luc bio-assay, whereafter sites eliciting quantifiable responses were selected for further chemical analysis by high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS). Of the 96 sites, only 23 had quantifiable levels of DLCs. These sites were mainly of industrial, semi-industrial or low-income residential nature. PAHs were the predominant class of compounds at most of the sites, while OCPs and PCBs were present in moderate concentrations and PBDEs in minor concentrations. The concentration of pollutants measured in South African soils and sediments were intermediate when compared to the levels measured in some European, Asian and Scandinavian countries, with the exception of a few sites where exceptionally high levels of compounds were measured. The carbon content normalized concentrations of certain compounds at some of the sites exceeded the Canadian sediment quality guidelines. The estimated cancer risk associated with dermal absorption of OCPs measured in this study was negligible when compared to the background cancer risk expected for South Africans due to life style factors. However, it was estimated that dermal exposure to PCBs, DLCs and PAHs may lead to severe increases in cancer cases, and may seriously impact on human health. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Water resources in South Africa are scarce, and should therefore be protected against pollutants, also from persistent organic pollutants (POPs). POPs are a global concern due to their ubiquitous presence, persistence and toxicity. This is emphasised by the Stockholm Convention on POPs, which aims at reducing and ultimately eliminating them. South Africa signed and ratified the treaty, and it became international law on 17 May 2004, but there is still a lack of information regarding POPs in South Africa. This study focussed on establishing the levels of POPs and other organic pollutants, which included various organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), dioxin-like compounds (DLCs), non-dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ether (PBDE). Sampling regions included the industrial cities – Cape Town, Richards Bay, Durban and Bloemfontein, and low-income, high density residential areas surrounding a wetland in Soweto/Lenasia and Botshabelo. Additionally, rivers flowing into neighbouring countries, rivers in the vicinity of paper and pulp producers and high altitude rivers were included. Sediment samples were firstly screened for the presence of DLCs by the H4IIE-luc bio-assay, whereafter sites eliciting quantifiable responses were selected for further chemical analysis by high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS). Of the 96 sites, only 23 had quantifiable levels of DLCs. These sites were mainly of industrial, semi-industrial or low-income residential nature. PAHs were the predominant class of compounds at most of the sites, while OCPs and PCBs were present in moderate concentrations and PBDEs in minor concentrations. The concentration of pollutants measured in South African soils and sediments were intermediate when compared to the levels measured in some European, Asian and Scandinavian countries, with the exception of a few sites where exceptionally high levels of compounds were measured. The carbon content normalized concentrations of certain compounds at some of the sites exceeded the Canadian sediment quality guidelines. The estimated cancer risk associated with dermal absorption of OCPs measured in this study was negligible when compared to the background cancer risk expected for South Africans due to life style factors. However, it was estimated that dermal exposure to PCBs, DLCs and PAHs may lead to severe increases in cancer cases, and may seriously impact on human health. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Elevated polychlorinated biphenyl (PCB) concentrations have been detected in marine mammals inhabiting the Strait of Georgia, British Columbia (Canada) and Puget Sound, Washington State (USA). This raises concerns about adverse health effects and underscores the importance of documenting source, transport, and fate of contaminants. This marine mammal-oriented study- (1) examines dietary exposure to complex mixtures of persistent organic pollutants (POPs); (2) characterizes POP accumulations using congener-specific contaminant analyses, stable isotope ratios, and multivariate statistical methods; and (3) explores some of the influencing factors for POP bioaccumulation in marine mammals. A first application of a food basket approach to assessing real-world dietary exposure to mixtures of chemicals in marine mammals has revealed Puget Sound as a regional “hotspot” for PCB contamination. The consistency between PCB concentrations in Puget Sound and the Strait of Georgia harbour seals (Phoca vitulina) and their food baskets validates the use of this method as a basis for exploring dietary exposure, metabolism, biomagnification, and health risks in marine mammals. Concentration rankings of POPs and estimated daily intakes based on our food baskets suggests that both legacy (e.g., PCB, dichlorodiphenyltrichloroethane [DDT]) and new (polybrominated diphenyl ethers [PBDEs]) POPs may pose potential health risks to seals. Accumulations of PCBs in the Strait of Georgia seal food web demonstrate the bioaccumulative nature and persistence of PCBs. Correlations of PCB concentrations with physicochemical properties and trophic level revealed the important role that metabolism plays in biomagnification in seals, alongside trophic level and log Kow. We estimate a PCB load of 77 kg within the Strait of Georgia biomass, with the largest proportion (36 %) detected in marine mammals. Dietary exposure of POPs to resident killer whales (Orcinus orca) was assessed by measuring POPs in four stocks of chinook salmon (Oncorhynchus tshawytscha), their primary prey. Differences in POP concentrations between chinook smolts and returning adults suggest that the majority of POPs are acquired at sea during the major growth period in their life cycle. Higher POP concentrations and low lipid content were observed among the more southerly stocks suggesting a migration-associated metabolism and loss of lighter congeners, thereby exposing southern residents to more highly contaminated chinook salmon. Consumption on a lipid-weight basis, (higher consumption on a wet weight basis), as well as consuming prey from a more contaminated region, likely increases killer whale exposure to POPs, offering an explanation for higher contaminant burdens in southern residents. While previous research has examined species inhabiting different trophic levels or food chains in other regions, this study has provided an assessment of POP dietary exposure, biomagnification, and influencing factors on trophic accumulations in a North-eastern Pacific marine mammal food web. These results have provided further insight into the influence of such factors as age, sex, lipid content, diet, migration-related metabolism, physicochemical properties (degree of chlorination, log Kow), and chemical structure on POP accumulation in marine mammals. We have identified the largely unregulated PBDEs as posing potential health risks to marine mammals and offered a means to update existing tissue residue guidelines for the protection of wildlife.