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Artykuły w czasopismach na temat "Dioxins"
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Marinković, Natalija, Daria Pašalić, Goran Ferenčak, Branka Gršković i Ana Rukavina. "Dioxins and Human Toxicity". Archives of Industrial Hygiene and Toxicology 61, nr 4 (1.12.2010): 445–53. http://dx.doi.org/10.2478/10004-1254-61-2010-2024.
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Dioxins and Human ToxicityThe term dioxins usually refers to polychlorinated dibenzo-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). As 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) has the highest toxic potential, the toxic potentials of other PCDDs and PCDFs are defined in comparison with it. Human exposure to dioxins can be environmental (background), occupational, or accidental pollution. In the human body, dioxins are in part metabolised and eliminated, and the rest is stored in body fat. People vary in their capacity to eliminate TCDD, but it is also dose-dependent; the elimination rate is much faster at higher than lower levels. The liver microsomal P4501A1 enzyme oxygenates lipophilic chemicals such as dioxins. It is encoded by the CYP1A1 gene. Cytosolic aryl hydrocarbon receptor (AhR) mediates their carcinogenic action. It binds to dioxin, translocates to nucleus and together with hydrocarbon nuclear translocator (ARNT) and xenobiotic responsive element (XRE) increases the expression of CYP1A1.Dioxins are classified as known human carcinogens, but they also cause noncancerous effects like atherosclerosis, hypertension, and diabetes. Long-term exposures to dioxins cause disruption of the nervous, immune, reproductive, and endocrine system. Short-term exposure to high levels impairs the liver function and causes chloracne. The most sensitive population to dioxin exposure are the foetuses and infants.A large number of health effects have been documented in the scientific literature, and they all place dioxins among the most toxic chemicals known to man.
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Ozaki, H., S. Taniguchi, R. Takanami, N. Shimomukai, T. Hamasaki, M. Sugahara i R. R. Giri. "Quantification of dioxin in the sieved fraction of river sediment". Water Science and Technology 52, nr 9 (1.11.2005): 225–33. http://dx.doi.org/10.2166/wst.2005.0325.
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Dioxin pollution of aquatic sediments has been one of the important environmental problems in Japan. Grain size distribution and organic constituents may play important roles in dioxins contents in sediments, which have not been well investigated. This paper aims to quantify dioxins (PCDDs/Fs and co-PCBs) in sieved surface sediment fractions obtained from Kizu and Sumiyoshi Rivers in Osaka, Japan. The samples were prepared and analyzed following the ‘Manual of the Survey and Measurement of Dioxins in Sediment’ (Environment Agency of Japan, 2000). The results showed that TEQ concentrations of dioxins increased with decreasing grain size in sediment fractions. Sediment fractions with less than 20μm grain size showed the highest dioxin contents. Dioxins with five and six chlorine atoms dominated other congeners in less than 20μm fractions. The dioxin TEQ concentrations increased with total organic carbon (TOC), total carbon (TC), ignition loss (IL), total sulphur and nitrogen contents in the sediment fractions. Thus, reporting dioxin contents in sediments without considering grain size distribution may be erroneous, and conventional sedimentation and separation techniques might not be useful for treating contaminated sediments. This information can be useful for effective remediation of dioxin-contaminated sediments.
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Mitoma, Yoshiharu, Maki Takase, Yoshiko Yoshino, Taizo Masuda, Hideki Tashiro, Naoyoshi Egashira i Takashi Oki. "Novel Mild Hydrodechlorination of PCDDs, PCDFs, and co-PCBs inside Fly Ash Using a Calcium-Promoted Rhodium Carbon Catalyst in Methanol". Environmental Chemistry 3, nr 3 (2006): 215. http://dx.doi.org/10.1071/en06002.
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Environmental Context. The generic term ‘dioxins’, the family of which includes polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like compounds such as coplanar polychlorinated biphenyls (co-PCBs), is used to describe highly toxic and mutagenic compounds. Many methods that involve high-temperature or high-pressure dry hydrogen conditions to ensure adequate decomposition for persistent chlorinated aromatic pollutants present disadvantages for repeated synthesis or recovery of vaporized dioxins and co-PCBs. We discovered that highly efficient degradation of dioxins in fly ash is accomplished in 24 h using metallic calcium and Rh/C in alcohol in a sealed tube at 25°C at 0.15 MPa. Abstract. Effective hydrodechlorination of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like compounds such as coplanar polychlorinated biphenyls in fly ash was achieved in 24 h using a simple stirring operation in a sealed tube with metallic calcium and Rh/C catalyst in an alcohol solution at room temperature with 0.15 MPa of increasing internal pressure. The initial 7806 pg dioxin toxic equivalent (TEQ) (g of ash)–1 of dioxins in fly ash, which had adsorbed inside the solid phase, was finally degraded to 23.6 pg of TEQ (g of ash)–1, according to estimation using gas chromatography–mass spectrometry analysis.
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Kang, Dongrui, Yao Bian, Qiqi Shi, Jianqiao Wang, Peng Yuan i Boxiong Shen. "A Review of Synergistic Catalytic Removal of Nitrogen Oxides and Chlorobenzene from Waste Incinerators". Catalysts 12, nr 11 (3.11.2022): 1360. http://dx.doi.org/10.3390/catal12111360.
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Emission of harmful gases, nitrogen oxides (NOx), and dioxins pose a serious threat to the human environment; so, it is urgent to control NOx and dioxin emissions. The new regulations for municipal solid waste incineration emissions set new stringent requirements for NOx and dioxin emission standards. Most of the existing pollutant control technologies focus on single-unit NOx reduction or dioxin degradation. However, the installation of separate NOx and dioxins removal units is space-consuming and costs a lot. Nowadays, the simultaneous elimination of NOx and dioxins in the same facility has been regarded as a promising technology. Due to the extremely high toxicity of dioxins, the less toxic chlorobenzene, which has the basic structure of dioxins, has been commonly used as a model molecule for dioxins in the laboratory. In this review, the catalysts used for nitrogen oxides/chlorobenzene (NOx/CB) co-removal were classified into two types: firstly, non-loaded and loaded transition metal catalysts, and their catalytic properties were summarized and outlined. Then, the interaction of the NH3-SCR reaction and chlorobenzene catalytic oxidation (CBCO) on the catalyst surface was discussed in detail. Finally, the causes of catalyst deactivation were analyzed and summarized. Hopefully, this review may provide a reference for the design and commercial application of NOx/CB synergistic removal catalysts.
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Chmil, V. D., O. V. Golokhova, D. Yu Vydrin i V. I. Kruk. "Relevance of the problem of dioxins and polychlorinated biphenyls (PCBs) determination in baby food products". One Health and Nutrition Problems of Ukraine 52, nr 1 (24.06.2020): 32–39. http://dx.doi.org/10.33273/2663-9726-2020-52-1-32-39.
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The Aim of the Article. Analysis of the current state of the problem of the dioxins and polychlorinated biphenyls (PCBs) determination in baby food products and the development of sample preparation methods for determining these xenobiotics in food products for infants and young children. Dioxins form a group of structurally and chemically related chlorinated tricyclic oxygen-containing aromatic compounds (congeners), which includes 75 polychlorinated dibenzo-para-dioxins (PCDDs) and 135 polychlorinated dibenzofurans (PCDFs). The most toxic congeners of dioxins, in which chlorine atoms along with other positions are necessarily in 2,3,7,8 positions of benzene rings. Their total number is 17:7 PCDD congeners and 10 PCDF congeners. A group of polychlorinated biphenyls (PCBs) – chlorinated bicyclic aromatic compounds, which consists of 209 different congeners, 12 of which have a spatial and electronic structure and exhibit toxicological properties similar to dioxins, therefore, they are called dioxin-like PCBs (DL-PCBs). In addition, when monitoring food products as a marker, a group of 6 PCBs was selected that did not exhibit dioxin-like toxicity and therefore did not belong to dioxin-like PCBs (NDL-PCBs). Thus, of the total number of 419 PCDDs, PCDFs and PCBs, only 35 are toxicologically significant, therefore, these compounds are subject to control in baby food products. To control the content of the amount of dioxins, the amount of dioxins and DL-PCBs and the amount of NDL-PCBs in foods for infants and children from one to three years in Ukraine, the maximum levels of these compounds on the basis of the order of the Ministry of Health of Ukraine No. 368 of 05/13/2013 were harmonized with the maximum allowable levels in foods for infants and young children in accordance with Commission Regulation (EU) No. 1259/2011. Methods for the analysis of dioxins and PCBs. Two instrumental analysis methods are used to determine dioxins and dioxin-like PCBs in foods for baby food: 1) a combination of high-resolution (capillary) gas chromatography with high-resolution mass spectrometry (GC/MS); 2) a combination of GCHR with tandem mass spectroscopy (GC/MS/MS). High-resolution (capillary) gas chromatography is used to determine non-dioxin-like (marker) PCBs. The stage of sample preparation, including the stages of extraction and purification, is key in determining dioxins and PCBs. Conclusions. The stage of sample preparation using automatic devices (liquid extraction under pressure, an automated extract purification system) and chromatographic columns was developed to further determine the mass concentration of dioxins and PCBs in baby food products. The developed procedures using devices for the automatic extraction and purification of the obtained extracts from baby food samples will make it possible in the future to determine PCDDs/PCDFs, ortho-unsubstituted, mono-ortho-substituted and marker PCBs in one sample. Key Words: dioxins, polychlorinated biphenyls, baby food.
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Sekine, Ayako. "Dioxins Problem. Achieving Zero Dioxin." Waste Management Research 8, nr 4 (1997): 312–21. http://dx.doi.org/10.3985/wmr.8.312.
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Gao, Xingbao, Bingjing Ji, Dahai Yan, Qifei Huang i Xuemei Zhu. "A full-scale study on thermal degradation of polychlorinated dibenzo-p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash and its secondary air pollution control in China". Waste Management & Research: The Journal for a Sustainable Circular Economy 35, nr 4 (30.11.2016): 437–43. http://dx.doi.org/10.1177/0734242x16677078.
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Degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash is beneficial to its risk control. Fly ash was treated in a full-scale thermal degradation system (capacity 1 t d−1) to remove polychlorinated dibenzo- p-dioxins and dibenzofurans. Apart from the confirmation of the polychlorinated dibenzo- p-dioxin and dibenzofuran decomposition efficiency, we focused on two major issues that are the major obstacles for commercialising this decomposition technology in China, desorption and regeneration of dioxins and control of secondary air pollution. The toxic equivalent quantity values of polychlorinated dibenzo- p-dioxins and dibenzofurans decreased to <6 ng kg−1 and the detoxification rate was ⩾97% after treatment for 1 h at 400 °C under oxygen-deficient conditions. About 8.49% of the polychlorinated dibenzo- p-dioxins and dibenzofurans in toxic equivalent quantity (TEQ) of the original fly ash were desorbed or regenerated. The extreme high polychlorinated dibenzo- p-dioxin and dibenzofuran levels and dibenzo- p-dioxin and dibenzofuran congener profiles in the dust of the flue gas showed that desorption was the main reason, rather than de novo synthesis of polychlorinated dibenzo- p-dioxins and dibenzofurans in the exhaust pipe. Degradation furnace flue gas was introduced to the municipal solid waste incinerator economiser, and then co-processed in the air pollution control system. The degradation furnace released relatively large amounts of cadmium, lead and polychlorinated dibenzo- p-dioxins and dibenzofurans compared with the municipal solid waste incinerator, but the amounts emitted to the atmosphere did not exceed the Chinese national emission limits. Thermal degradation can therefore be used as a polychlorinated dibenzo- p-dioxin and dibenzofuran abatement method for municipal solid waste incinerator source in China.
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He, Hao, Xuanhao Guo, Lizheng Jin, Yaqi Peng, Minghui Tang i Shengyong Lu. "The Effect of Adjusting Sinter Raw Mix on Dioxins from Iron Ore Co-Sintering with Municipal Solid Waste Incineration Fly Ash". Energies 15, nr 3 (3.02.2022): 1136. http://dx.doi.org/10.3390/en15031136.
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The inhibition effect of calcined lime (CaO) and limestone (CaCO3) on the formation of dioxins during iron ore co-sintering with fly ash was investigated in a sinter pot in the present work. Experimental results indicated that international total toxicity equivalent concentration of dioxins decreased from 1.4335 to 0.2922, 0.1048, 0.4562, and 0.3098 ng I-TEQ Nm−3 under four different experimental conditions. It can be concluded that 5 wt.% calcined lime with 3 wt.% limestone is the optimal addition to reduce the concentration of dioxins in flue gas, with 92.70% inhibition efficiency. Effects on dioxin distribution was also analyzed. The distribution proportion of low-chlorinated dioxins was found to increase, while that of high-chlorinated dioxins decreased, except for octachlorianted dibenzo-p-dioxins (OCDD). The reason is that the consumption of HCl not only inhibits the de novo synthesis, but also dramatically promotes the condensation and dechlorination to produce more tetrachlorianted dibenzo-p-dioxins and octachlorianted dibenzo-p-dioxins through precursors. Finally, condensation, dichlorination, and inhibition mechanisms of dioxins during co-sintering with municipal solid waste incineration (MSWI) fly ash are proposed.
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Gorman, J., K. Mival, J. Wright i M. Howell. "Developing risk-based screening guidelines for dioxin management at a Melbourne sewage treatment plant". Water Science and Technology 47, nr 10 (1.05.2003): 1–7. http://dx.doi.org/10.2166/wst.2003.0523.
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Dioxin is a generic term used to refer to the congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The principal source of dioxin production is generally thought to be from unintended by-products of waste incineration, but dioxins are also naturally formed from volcanic activity and forest fires (WHO, 1998). Estimates of dioxin emissions in Australia suggest that approximately 75% of the total PCDD and PCDF emissions derive from prescribed burning and wild bushfires. Currently, no screening guidelines for dioxins within soils are available in Australia. This paper presents the general approach and results of a human health risk-based assessment performed by URS Australia in 2001 to develop site specific reference criteria for remediation of a former sewage treatment plant in Melbourne. Risk-based soil remediation concentrations for dioxins at the sewage treatment plant site were developed using tolerable daily intake values of 4, 2 and 1 pg/kg/day. The potentially significant exposure pathways and processes for exposure to dioxins were identified and risk-based soil concentrations derived in accordance with the general method framework presented in the National Environmental Protection Measure (Assessment of Site Contamination). The derived dioxin reference criteria were used to develop an effective risk management program focussed on those conditions that present the greatest contribution to overall risk to human health.
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Çalışlar, Süleyman, i Mesut Karaman. "Dioksinlerin Hayvan Beslemedeki Genel Etkileri". Turkish Journal of Agriculture - Food Science and Technology 5, nr 6 (14.07.2017): 687. http://dx.doi.org/10.24925/turjaf.v5i6.687-694.1176.
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Dioxins is one of the chemicals groups that cause liver toxicity, live weight reduction, immune suppression, reproductive impairments, eggshell thinning, birth defects, cancers and death in animals. The 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) is the most poisonous environmental chemical and many studies were showed high dosage of TCDD affects all animal group. Also TCDD increase cancer risk in human so this chemical described as carcinogenic by International Agency for Research on Cancer. Dioxins are stored in animal foods such as meat, milk, eggs and fish, because they are soluble in oil and remain in these products for many years. Dioxins can dissolve in fat and high stability therefore it can be infected to meat, milk, egg, and fish and store there for long time as a result people could be contained with dioxin during daily life. Animal feed additives such as organic acids, pH modifiers, starch, sugar, vegetable oil, fat, fruit and by-products of plant, kaolinite, rendering products, pelleting aids cause dioxin contamination. The maximum dioxin content in plant-origin feedstuffs and their by-products is 0.75 ng toxic equivalent/kg body weight. In this rewiew, the effects of dioxins on livestock feeding was examined.
Rozprawy doktorskie na temat "Dioxins"
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Jansson, Stina. "Thermal formation and chlorination of dioxins and dioxin-like compounds". Doctoral thesis, Umeå universitet, Kemi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1881.
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This thesis contributes to an increased understanding of the formation of dioxins and dioxin-like compounds in combustion processes. Although emissions to air from waste incineration facilities have been greatly reduced by the use of efficient air pollution control measures, the resulting residues (ashes and filters) are highly toxic and are classified as hazardous waste. The main objective of the work underlying this thesis was to elucidate the formation and chlorination pathways of dioxins and dioxin-like compounds in waste combustion flue gases in the temperature range 640-200°C in a representative, well-controlled laboratory-scale reactor using artificial municipal solid waste. This could contribute to the reduction of harmful emissions to air and also reduce the toxicity of waste incineration residues, thus reducing or even eliminating the need for costly and potentially hazardous after-treatment. A comparison of four different quenching profiles showed that the formation of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) was rapid and mainly occurred in the 640-400°C temperature region, with high dependency on sufficient residence time within a specific temperature region. Prolonged residence time at high temperatures (450/460°C) reduced the PCDD yields, even at lower temperatures along the post-combustion zone. PCDD, PCDF and PCN (polychlorinated naphthalene) isomer distribution patterns indicated contributions from chlorophenol condensation as well as chlorination reactions for all three classes of compounds. The formation of PCDDs was largely influenced by chlorophenol condensation and to some extent by chlorination reactions. For the PCDFs, chlorine substitution adjacent to the oxygen bridges was unfavoured, as demonstrated by the notably lower abundance of 1,9-substituted congeners. This was supported by bidirectional orthogonal partial least squares (O2PLS) modelling. The variable with the greatest influence on the distribution of PCDD congeners was the relative free energy (RΔGf). The O2PLS models displayed distinct clusters, dividing most of the homologues into two or three sub-groups of congeners which seemed to correspond to the probability of origination from chlorophenol condensation. The effects of injection of aromatic structures into the flue gas differed for each class of compounds. Injection of naphthalene increased the formation of monochlorinated naphthalene but the remaining homologues appeared to be unaffected. This was probably due to insufficient residence time at temperatures necessary for further chlorination. Injected dibenzo-p-dioxin was decomposed, chlorinated and re-condensated into PCDDs and PCDFs, whereas injection of dibenzofuran and fluorene reduced the PCDD levels in the flue gas.Denna avhandling fokuserar på olika aspekter som kan bidra till en ökad förståelse av bildning av dioxiner och dioxin-lika föreningar i förbränningsprocesser. Även om utsläppen till luft från sopförbränningsanläggningar har minskat kraftigt tack vare effektiva rökgasreningsmetoder, så återstår problemet med mycket giftiga rökgasreningsprodukter (askor och filter), vilka klassificeras som farligt avfall. Det huvudsakliga syftet med arbetet bakom denna avhandling var att klarlägga bildnings- och kloreringsvägarna för dioxiner och dioxin-lika föreningar i temperaturintervallet 640-200°C i rökgaser från sopförbränning. Detta kan möjliggöra lösningar för ytterligare emissionsminskningar och en avgiftning av biprodukterna från avfallsförbränning, vilket minskar eller till och med eliminerar behovet av kostsam och riskfylld efterbehandling. Realistiska och välkontrollerade försök har utförts i en lab-skalereaktor där en artificiell hushållssopa har förbränts. En jämförelse av fyra olika temperatur- och uppehållstidsprofiler visade att bildning av polyklorerade dibenso-p-dioxiner (PCDD) och dibensofuraner (PCDF) sker snabbt och huvudsakligen inom temperaturintervallet 640-400°C. Bildningen var starkt beroende av en tillräckligt lång uppehållstid inom ett visst temperaturområde. En förlängd uppehållstid vid höga temperaturer (>450°C) resulterade i minskade halter av PCDD, vilka förhöll sig låga även senare i efterförbränningszonen. Isomermönstren av PCDD, PCDF och PCN (polyklorerade naftalener) visade alla tecken på att härröra från både klorfenolkondensation och kloreringsreaktioner. PCDD-mönstret visade tydliga indikationer på bildning från klorfenoler, och till mindre grad bildning via klorering. För PCDF var klorsubstitution i positioner angränsande till syrebryggan missgynnad, vilket bekräftades av multivariat modellering (O2PLS). Den variabel som starkast påverkade bildningen av PCDD var relativa fria energin (RΔGf). Modellerna visade på en distinkt gruppering av PCDD- och PCDF-kongenerna i två eller tre grupper för varje kloreringsgrad, och föreslås vara relaterad till sannolikheten för respektive kongen att bildas via klorfenolkondensation. Injektion av aromatiska kolstrukturer i rökgaskanalen gav upphov till skilda effekter. Injektion av naftalen ökade bildningen av monoklorerad naftalen medan resterande homologer inte verkade påverkas, sannolikt på grund av för kort uppehållstid för ytterligare klorering. Dibenso-p-dioxin spjälkades sannolikt till fenoliska fragment som klorerades och sedan återkondenserades till PCDD och PCDF, medan dibensofuran och fluoren kraftigt reducerade PCDD-koncentrationerna.
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Furness, Sebastian George Barton. "Novel mechanisms for activation of the dioxin (Aryl-hydrocarbon) receptor /". Title page, table of contents and summary only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phf988.pdf.
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Gao, Qiuju. "Dioxins and dioxin-like compounds in thermochemical conversion of biomass : formation, distribution and fingerprints". Doctoral thesis, Umeå universitet, Kemiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-118861.
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In the transition to a sustainable energy supply there is an increasing need to use biomass for replacement of fossil fuel. A key challenge is to utilize biomass conversion technologies in an environmentally sound manner. Important aspects are to minimize potential formation of persistent organic pollutants (POPs) such as dioxins and dioxin-like compounds. This thesis involves studies of formation characteristics of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and naphthalenes (PCNs) in microwave-assisted pyrolysis (MAP) and torrefaction using biomass as feedstock. The research focuses are on their levels, distributions, fingerprints (homologue profiles and isomer patterns) and the underlying formation pathways. The study also included efforts to optimize methods for extracting chlorinated aromatic compounds from thermally treated biomass. The overall objective was to contribute better understanding on the formation of dioxins and dioxin-like compounds in low temperature thermal processes. The main findings include the following: Pressurized liquid extraction (PLE) is applicable for simultaneous extraction of PCDDs, PCDFs, PCNs, polychlorinated phenols and benzenes from thermally treated wood. The choice of solvent for PLE is critical, and the extraction efficiency depends on the degrees of biomass carbonization. In MAP experiments PCDDs, PCDFs and PCNs were predominantly found in pyrolysis oils, while in torrefaction experiments they were mainly retained in solid chars with minor fractions in volatiles. In both cases, highly chlorinated congeners with low volatility tended to retain on particles whereas the less chlorinated congeners tended to volatize into the gas phase. Isomer patterns of PCDDs, PCDFs and PCNs generated in MAP were more selective than those reported in combustion processes. The presence of isomers with low thermodynamic stability suggests that the pathway of POPs formation in MAP may be governed not only by thermodynamic stabilities but also by kinetic factors. Formation of PCDDs, PCDFs and PCNs depends not only on the chlorine contents in biomass but also the presence of metal catalysts and organic/metal-based preservatives. Overall, the results provide information on the formation characteristics of PCDDs, PCDFs and PCNs in MAP and torrefaction. The obtained knowledge is useful regarding management and utilization of thermally treated biomass with minimum environmental impact.
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Prange, Joelle, i n/a. "Origin of Dioxins in Queensland: Investigations into the Distribution and Sources of Polychlorinated Dibenzo-P-Dioxins in the Queensland Terrestrial Environment". Griffith University. School of Public Health, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040615.161651.
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Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are persistent organic pollutants of global concern as they are persistent, toxic and can biomagnify through the food chain. PCDD/Fs are generally regarded as trace contaminants in a number of chemical products and they are formed as by-products from various industrial, chemical and combustion processes. The pollution with PCDD/Fs occurs with the release of these chemicals into the environment, resulting in the contamination of various compartments including; air, soil, sediment and biota. Studies that have investigated the distribution of PCDD/Fs in the environment suggest that the highest concentrations of these pollutants are found in locations with a history of industrial or chemical PCDD/F sources. Queensland is the north-eastern state of Australia. Queensland has a low population density, few industrial activities and is considered predominantly rural. Therefore it was somewhat surprising that elevated concentrations of PCDD/Fs (in particular the higher chlorinated PCDDs) have been observed in soil and sediments samples collected from various locations along the Queensland coast. The concentrations of PCDDs in Queensland samples were comparable to or higher than concentrations in similar matrices from highly polluted regions elsewhere. To investigate the origin of PCDDs in Queensland, the geographical distribution of PCDD/Fs in topsoil was investigated in the coastal and inland environments to provide information on the potential sources and to estimate the extent of the PCDD contamination. Distinct east-west gradients were detected in topsoil collected from bushland areas across the state with elevated PCDD concentrations confined to the coastal region. Within the coastal region, the contamination could not be associated with specific land uses. In fact, the PCDD/F congener profile was similar in the majority of samples from the coastal region, with a dominance of the higher chlorinated PCDDs (in particular OCDD), whereas PCDFs were low or below the limit of detection. The similarity in the PCDD/F congener profiles in the soils along the coastal region indicated that a source of PCDDs of similar origin has resulted in the contamination of soil extending more than 3000 km and estimations suggest that more than 50 tonnes of OCDD is stored in the topsoil of Queensland.s coastal region. Investigation into the vertical distribution of PCDDs in Queensland coastal soils revealed elevated concentrations of PCDDs, (in particular OCDD) in soils to at least 3.5 m. These results indicated that the extent of the PCDD contamination is significantly greater than anticipated and it was estimated that there is in the order of 3 000 tonnes of OCDD stored in Queensland's coastal soils. The specific PCDD/F congener profile in Queensland coastal soils is unlike known PCDD/F source profiles which led to the suggestion that some yet unidentified formation mechanism may have resulted in the contamination. Potential natural sources of PCDD/Fs, including forest fires, geogenic and biogenic processes were assessed as possible origins for the PCDD contamination in Queensland. Elevated concentrations of PCDDs were detected in the atmosphere during a 'prescribed burn'. This study demonstrated that although forest fires influence atmospheric PCDD/F concentrations substantially, forest fires are not the source of PCDDs in Queensland; rather they are an important mechanism for the redistribution of PCDDs and may have attributed to the widespread PCDD contamination. In this study geological materials (oil shale and kaolin) were analysed as a proxy to assess a geogenic origin of PCDDs. Elevated concentrations of PCDDs were observed in the kaolin samples, however similar and higher concentrations were detected in surface and sub-surface soils, suggesting that specific geogenic formation processes investigated are not the source of PCDDs in Queensland. A preliminary indication for a biogenic origin of PCDDs was identified during the anaerobic incubation of sugarcane irrigation sediments. An increase in the concentration of OCDD in the anaerobic treatment, compared to the control was observed after incubation for 90 days. In these same experiments, a dechlorination of OCDD to lower chlorinated (1,4,6,9-substituted) PCDDs was also observed. Similar transformation processes were observed in other anaerobic environments in Queensland, which led to the suggestion that a biogenic formation of PCDDs (possibly from a precursor) may be responsible for the origin of PCDDs in Queensland.
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Prange, Joelle. "Origin of Dioxins in Queensland: Investigations into the Distribution and Sources of Polychlorinated Dibenzo-P-Dioxins in the Queensland Terrestrial Environment". Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367289.
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Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are persistent organic pollutants of global concern as they are persistent, toxic and can biomagnify through the food chain. PCDD/Fs are generally regarded as trace contaminants in a number of chemical products and they are formed as by-products from various industrial, chemical and combustion processes. The pollution with PCDD/Fs occurs with the release of these chemicals into the environment, resulting in the contamination of various compartments including; air, soil, sediment and biota. Studies that have investigated the distribution of PCDD/Fs in the environment suggest that the highest concentrations of these pollutants are found in locations with a history of industrial or chemical PCDD/F sources. Queensland is the north-eastern state of Australia. Queensland has a low population density, few industrial activities and is considered predominantly rural. Therefore it was somewhat surprising that elevated concentrations of PCDD/Fs (in particular the higher chlorinated PCDDs) have been observed in soil and sediments samples collected from various locations along the Queensland coast. The concentrations of PCDDs in Queensland samples were comparable to or higher than concentrations in similar matrices from highly polluted regions elsewhere. To investigate the origin of PCDDs in Queensland, the geographical distribution of PCDD/Fs in topsoil was investigated in the coastal and inland environments to provide information on the potential sources and to estimate the extent of the PCDD contamination. Distinct east-west gradients were detected in topsoil collected from bushland areas across the state with elevated PCDD concentrations confined to the coastal region. Within the coastal region, the contamination could not be associated with specific land uses. In fact, the PCDD/F congener profile was similar in the majority of samples from the coastal region, with a dominance of the higher chlorinated PCDDs (in particular OCDD), whereas PCDFs were low or below the limit of detection. The similarity in the PCDD/F congener profiles in the soils along the coastal region indicated that a source of PCDDs of similar origin has resulted in the contamination of soil extending more than 3000 km and estimations suggest that more than 50 tonnes of OCDD is stored in the topsoil of Queensland.s coastal region. Investigation into the vertical distribution of PCDDs in Queensland coastal soils revealed elevated concentrations of PCDDs, (in particular OCDD) in soils to at least 3.5 m. These results indicated that the extent of the PCDD contamination is significantly greater than anticipated and it was estimated that there is in the order of 3 000 tonnes of OCDD stored in Queensland.s coastal soils. The specific PCDD/F congener profile in Queensland coastal soils is unlike known PCDD/F source profiles which led to the suggestion that some yet unidentified formation mechanism may have resulted in the contamination. Potential natural sources of PCDD/Fs, including forest fires, geogenic and biogenic processes were assessed as possible origins for the PCDD contamination in Queensland. Elevated concentrations of PCDDs were detected in the atmosphere during a 'prescribed burn'. This study demonstrated that although forest fires influence atmospheric PCDD/F concentrations substantially, forest fires are not the source of PCDDs in Queensland; rather they are an important mechanism for the redistribution of PCDDs and may have attributed to the widespread PCDD contamination. In this study geological materials (oil shale and kaolin) were analysed as a proxy to assess a geogenic origin of PCDDs. Elevated concentrations of PCDDs were observed in the kaolin samples, however similar and higher concentrations were detected in surface and sub-surface soils, suggesting that specific geogenic formation processes investigated are not the source of PCDDs in Queensland. A preliminary indication for a biogenic origin of PCDDs was identified during the anaerobic incubation of sugarcane irrigation sediments. An increase in the concentration of OCDD in the anaerobic treatment, compared to the control was observed after incubation for 90 days. In these same experiments, a dechlorination of OCDD to lower chlorinated (1,4,6,9-substituted) PCDDs was also observed. Similar transformation processes were observed in other anaerobic environments in Queensland, which led to the suggestion that a biogenic formation of PCDDs (possibly from a precursor) may be responsible for the origin of PCDDs in Queensland.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Public Health
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Machado, Diego Henrique de Oliveira. "Investigação das propriedades ópticas, morfológicas e elétricas da heterojunção SnO2:Ce3+/GaAs /". Bauru, 2016. http://hdl.handle.net/11449/135900.
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Orientador: Luís Vicente de Andrade ScalviBanca: Dayse Iara dos Santos
Banca: Anrea Simone Stucchi de Camargo
O Programa em Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi
Resumo: Este trabalho apresenta o desenvolvimento e algumas conclusões do estudo de heterojunção de filmes finos de SnO2 e GaAs. Os filmes de SnO2 dopados com Ce3+, foram depositados a partir do método sol-gel usando as técnicas de dip e spin coating; os filmes de GaAs foram depositadas por evaporação resistiva e por sputtering. As heterojunções foram constituídas de filmes de SnO2 sobre filmes de GaAs, e filmes de GaAs sobre filmes de SnO2. Foram investigadas as propriedades ópticas, estruturais, morfológicas e elétricas de filmes finos constituintes das heterojunções e também a influência do dopante Ce3+. Entre os experimentos realizados estão: transmitância óptica, difração de raios X, microscopia eletrônica de varredura (MEV), microscopia óptica, microscopia de força atômica (AFM), fotoluminescência e medidas elétricas na presença de excitações com diferentes fontes de luz monocromáticas (quarto harmônico do laser Nd:Y AG (266nm), laser He-Ne (628nm), LED InGaN (450nm)). Entre as principais conclusões, verificou-se: 1) em algumas situações, condutividade independente da temperatura, sugerindo a participação de um gás de elétrons bidimensional (2DEG) na interface SnO2/GaAs; 2) o tamanho dos cristalitos, calculado a partir das análises de difração de raios X, fornece valores da ordem de 10 nm tanto para filmes de SnO2 como para filmes de GaAs; 3) a energia de bandgap, avaliada com base em dados de medidas de absorbância, fornece um valor máximo de 3,6 eV para filmes de dióxido de estanho e 1,6eV para filmes de GaAs; 4) MEV e microscopia óptica de para filmes de GaAs (depositado por evaporação resistiva e sputtering) apresentam sua superfície heterogênea, com partículas de variados tamanhos. Além disso, a aderência de filmes de SnO2 sobre filmes de GaAs está relacionada com a técnica utilizada para depositar os filmes da camada de base, o melhor resultado foi obtido quando a camada é a GaAs...
Abstract: The aims of this work is to present the development and the main conclusion, related the investigation of thin film SnO2/GaAs. Os filmes de SnO2/GaAs heterojunction. Ce3+ - doped SnO2 thin films were deposited by the sol-gel-dip -spin coating techniques, whereas GaAs films were deposited by resistive evaporation and sputerring. Heterojunctions were deposited by SnO2 layer growth on the oppositive order: GaAs on top of SnO2 Optical, structural, morphologic and electrical properties of heterojunction films were investigated, as well as the influence of Ce-doping in these measurements. Experiments carried out include: optical transmission, X-ray diffraction, scanning eletron microscopy (SEM), optical microscopy, atomic force microscopy (AFM), photoluminescence and electrical measurement under optical excitation. In this last case the excitation sources are monochromatic light from the fouth harmonic of a Nd:YAG laser (266nm), a He-Ne laser (628nm) and a InGaN LED (450nm). Among the main conclusions, it was verified that: 1) in some situations, a temperature independent electrical resistivity was observed and attributed to the possible formation of a two-dimensional electron gas (2DEG) at SnO2/GaAs interface; 2) crystalline size was calculated from X-ray diffraction data, being about 10 nm either for SnO2 films as GaAs films; 3) bandgap energy, evaluated from absorbance data yield a maximum value of about 3.6eV for tin dioxide and 1.6eV for GaAs films; 4) SEM images, obtained for GaAs thin films deposited by resistive evaporation and for the heterojuntion SnO2/GaAs, and optical microscopy, for sputtering deposited GaAs films and heterojunction samples, show that GaAs films present an heterogeneous surface, with particles of several distinct sizes. Besides, the adherence of SnO2 films on the GaAs layer is related to the used technique for deposition the base layer, being better in the case of resistive evaporation deposited GaAs. This was...
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Gaus, Caroline, i n/a. "Dioxins in the Marine Environment: Sources, Pathways and Fate of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Queensland, Australia". Griffith University. School of Public Health, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030624.144111.
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Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans(PCDFs) are two groups of lipophilic, persistent organic pollutants that are produced as by-products of various anthropogenic and industrial processes. Due to their relatively high toxic potencies and potential to bioaccumulate and biomagnify in organisms and through the food chain, the contemporary widespread distribution of these compounds is a concern to the health of the environment, wildlife and humans. This study determined the distribution, pathways and fate of PCDD/Fs in the coastal zone of Queensland, Australia, including the inshore marine environment of the World Heritage Great Barrier Reef Marine Park. This ecosystem supports unique fauna and flora such as the marine herbivorous mammal dugong (Dugong dugon) and its food source, seagrass. Elevated PCDD/Fs were present in soils and sediments along the entire Queensland coastline. Highest concentrations were found in soil from agricultural irrigation drains and in sediments near the mouths of major rivers. Elevated concentrations were associated with rural and urban types of land-use, and PCDD/Fs were present even in locations remote from anthropogenic activities. PCDD/F congener-specific analysis revealed an unusual profile in all samples, dominated by OCDD, with PCDFs present in low concentrations or below the limit of detection. Distinct HxCDD isomer patterns were observed, with the 1,2,3,7,8,9-HxCDD/1,2,3,4,6,7-HxCDD isomer pair dominating the 2,3,7,8-substituted HxCDDs. Similar congener and isomer characteristics were reported in sediments, soil and clay samples from other continents, but could not be attributed to any known source. Possible PCDD/F sources in Queensland were assessed using segmented estuarine sediment cores, for which radiochemical chronologies were established for each depth. Variations of PCDD/F concentrations in the sediment cores over several centuries of depositional history were relatively small. Elevated PCDD levels were still present in sediment slices from the early 17th century. PCDD/F homologue profiles in sediments deposited during the last 350 years were almost identical and correlated well to the characteristic profiles observed in surface sediments and soils from the entire Queensland coastline. These results suggested the presence of an unidentified PCDD source prior to the production of commercial organochlorine products. To investigate the formation of the unusual PCDD/F profiles, congener and isomer specific analyses were undertaken in soils, sediments and dated sediment cores. The results demonstrated that specific transformation processes in the environment have resulted in the observed PCDD profile characteristics. Dechlorination of OCDD was proposed to result in distinct 1,4-pattern characteristics (i.e. formation of isomers chlorinated in the 1,4,6,9-positions). Consequently, the environmental samples do not reflect the signatures of the original source. An alternative hypothesis to natural formation is discussed evaluating these processes and their implications for possible source contributions. This hypothesis explores the potential for the influence of anthropogenic PCDD precursors (e.g. pentachlorophenol) during the 1940s to 1990s. Transport of PCDD/Fs from the land-based source via impacted tributary river systems, and subsequent deposition processes are proposed to result in PCDD/F accumulation in the inshore marine ecosystem. The extent of the sediment PCDD/F contamination governs the concentrations in the extensive inshore marine seagrass meadows of Queensland. Partitioning processes in the sediment-seagrass system lead to increased toxic equivalency (TEQ) in the seagrass, compared to sediment.The relationship between contaminated inshore sediments, seagrass and dugongs were evaluated using six dugong habitat regions along the coastline. PCDD/F body burdens in dugongs are governed by sediment (and seagrass) PCDD/F concentrations in their habitat. High seagrass (and incidental sediment) ingestion rates, selective retention of toxicologically potent congeners and relatively low PCDD/F elimination capacities in dugongs are proposed to result in elevated PCDD/F concentrations and TEQ levels in adult animals. Transfer efficiencies of 4 and 27% of maternal TEQ levels to foetuses and calves (respectively) during gestation and lactation result in relatively high exposure potentials to offspring. Compared to no-observed-adverse-effect-levels in other mammals, and based on the results of this study, a tolerable daily intake (TDI) of 10-24 pg TEQ kg-1 day-1 was estimated for dugongs. The results of the present study found that dugongs from some regions along the coastline of Queensland exceed this TDI by up to 20 fold, suggesting that these populations may be at risk from PCDD/F contamination in their habitat. These results have important implications for the health of the environment, wildlife and humans and were used to develop a conceptual understanding of the sources, pathways and fate of dioxins in Queensland, Australia.
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Gaus, Caroline. "Dioxins in the Marine Environment: Sources, Pathways and Fate of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Queensland, Australia". Thesis, Griffith University, 2003. http://hdl.handle.net/10072/367537.
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Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans(PCDFs) are two groups of lipophilic, persistent organic pollutants that are produced as by-products of various anthropogenic and industrial processes. Due to their relatively high toxic potencies and potential to bioaccumulate and biomagnify in organisms and through the food chain, the contemporary widespread distribution of these compounds is a concern to the health of the environment, wildlife and humans. This study determined the distribution, pathways and fate of PCDD/Fs in the coastal zone of Queensland, Australia, including the inshore marine environment of the World Heritage Great Barrier Reef Marine Park. This ecosystem supports unique fauna and flora such as the marine herbivorous mammal dugong (Dugong dugon) and its food source, seagrass. Elevated PCDD/Fs were present in soils and sediments along the entire Queensland coastline. Highest concentrations were found in soil from agricultural irrigation drains and in sediments near the mouths of major rivers. Elevated concentrations were associated with rural and urban types of land-use, and PCDD/Fs were present even in locations remote from anthropogenic activities. PCDD/F congener-specific analysis revealed an unusual profile in all samples, dominated by OCDD, with PCDFs present in low concentrations or below the limit of detection. Distinct HxCDD isomer patterns were observed, with the 1,2,3,7,8,9-HxCDD/1,2,3,4,6,7-HxCDD isomer pair dominating the 2,3,7,8-substituted HxCDDs. Similar congener and isomer characteristics were reported in sediments, soil and clay samples from other continents, but could not be attributed to any known source. Possible PCDD/F sources in Queensland were assessed using segmented estuarine sediment cores, for which radiochemical chronologies were established for each depth. Variations of PCDD/F concentrations in the sediment cores over several centuries of depositional history were relatively small. Elevated PCDD levels were still present in sediment slices from the early 17th century. PCDD/F homologue profiles in sediments deposited during the last 350 years were almost identical and correlated well to the characteristic profiles observed in surface sediments and soils from the entire Queensland coastline. These results suggested the presence of an unidentified PCDD source prior to the production of commercial organochlorine products. To investigate the formation of the unusual PCDD/F profiles, congener and isomer specific analyses were undertaken in soils, sediments and dated sediment cores. The results demonstrated that specific transformation processes in the environment have resulted in the observed PCDD profile characteristics. Dechlorination of OCDD was proposed to result in distinct 1,4-pattern characteristics (i.e. formation of isomers
chlorinated in the 1,4,6,9-positions). Consequently, the environmental samples do not reflect the signatures of the original source. An alternative hypothesis to natural formation is discussed evaluating these processes and their implications for possible source contributions. This hypothesis explores the potential for the influence of anthropogenic PCDD precursors (e.g. pentachlorophenol) during the 1940s to 1990s. Transport of PCDD/Fs from the land-based source via impacted tributary river systems, and subsequent deposition processes are proposed to result in PCDD/F accumulation in the inshore marine ecosystem. The extent of the sediment PCDD/F contamination governs the concentrations in the extensive inshore marine seagrass meadows of Queensland. Partitioning processes in the sediment-seagrass system lead to increased toxic equivalency (TEQ) in the seagrass, compared to sediment.The relationship between contaminated inshore sediments, seagrass and dugongs were evaluated using six dugong habitat regions along the coastline. PCDD/F body burdens in dugongs are governed by sediment (and seagrass) PCDD/F concentrations in their habitat. High seagrass (and incidental sediment) ingestion rates, selective retention of toxicologically potent congeners and relatively low PCDD/F elimination capacities in dugongs are proposed to result in elevated PCDD/F concentrations and TEQ levels in adult animals. Transfer efficiencies of 4 and 27% of maternal TEQ levels to foetuses and calves (respectively) during gestation and lactation result in relatively high exposure potentials to offspring. Compared to no-observed-adverse-effect-levels in other mammals, and based on the results of this study, a tolerable daily intake (TDI) of 10-24 pg TEQ kg-1 day-1 was estimated for dugongs. The results of the present study found that dugongs from some regions along the coastline of Queensland exceed this TDI by up to 20 fold, suggesting that these populations may be at risk from PCDD/F contamination in their habitat. These results have important implications for the health of the environment, wildlife and humans and were used to develop a conceptual understanding of the sources, pathways and fate of dioxins in Queensland, Australia.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Public Health
Faculty of Health Sciences
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Cantrell, Susannah M. "Embryotoxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)". free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9924870.
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Le, Van Anh. "SOURCES OF DIOXINS TO BALTIC AIR Volatilization and Resuspension As Potential Secondary Sources of Dioxins to Air". Thesis, Umeå universitet, Kemiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-56570.
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Persistent organic pollutants (POPs) are ubiquitous contaminants characterized by semi-volatility, low water solubility, high lipophilicity and inherent toxicity. A combination of these properties results in long-rang transport, bioaccumulation and biomagnification through food webs. Elimination of the production, use and emissions of these POPs has been ongoing since the 1970s. However, the levels of some POPs are still unacceptably high in some parts of the environment and due to their high persistence levels only decline very slowly over a long period of time. This is especially true for POPs in the Baltic Sea due to long water residence time of approximately 40 years. Numerous studies have been carried out to explore the behavior and fate of the POPs in Baltic regions using analytical methods or modeling approaches. Air-soil exchange plays an important role in controlling the environmental fate of POPs in surface media. Air is a transport medium, which spreads chemicals far away from sources. Soils have received an input of POPs from the atmosphere over a long time period. These chemicals have accumulated in soil solids and, as primary emissions are released, can potentially be rereleased to other environmental media. Therefore, soil could become a significant "secondary" source of some POPs to the air. In this study, the aim was to determine if volatilization and/or resuspension are potential sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) ("dioxins") to Baltic air. Sources of these compounds to Baltic air are particularly interesting because levels of dioxins in fatty fish in the Baltic exceed the levels that are considered fit for human consumption in the European Union guideline. The fugacity quotient approach has been previously shown to be a useful method for exploring the equilibrium status of two connected environmental compartments. Fugacity quotients between the atmosphere and soil are calculated for seventeenth toxic 2, 3, 7, 8,-substituted dioxin congeners . A multimedia mass balance model designed for the Baltic Sea region (POPCYCLING-Baltic) is also employed to study the long-term exchange between air and soil. Estimated fugacity ratios from model simulations are compared with calculated fugacity quotients. Moreover, sensitive analysis is undertaken in order to evaluate the relative effect of background concentration, resuspension and bioturbation transport to the transfer flux from soil to air. Master’s Thesis 2011 II Fugacities of dioxins in soil are additionally measured directly using equilibrium passive sampling devices. Among available passive samplers, polyoxymethylene 17 μm (POM-17) are chosen to absorb freely dissolved PCDD/Fs molecules in soil. Total soil concentrations are measured to provide input data for the POPCYCLING-Baltic multimedia fate and transport model. Estimated fugacities of dioxins will be compared with directly "measured" fugacities in soil. The predictive ability of the model is assesses by comparing estimated and "measured" fugacity. Calculated fugacity quotients showed that lower chlorinated dibenzofuran are close to equilibrium between soil and air while other congeners show disequilibrium. Estimated soil/air fugacity ratios are higher than one but soil still accumulates dioxins because transport process is very slow and non-equilibrium can be maintained for a long period of time. Due to the seasonal variation in concentration, volatilization is higher in summer than in winter. Therefore, net gaseous flux between soil and air can be observed in summer. Sensitivity analysis revealed that volatilization flux is proportional to background soil concentration. High background soil concentration results in high volatilization fluxes and vice versa. The simulation showed that the contribution of resuspension flux to air pollution levels is relatively small in comparison to the influence of variation in background soil concentration. If relatively high and unrealistic resuspension velocities are used as inputs in the model, resuspension is a significant source to the atmosphere. In contrast to background soil concentration and resuspension, bioturbation has no effect on volatilization flux even though high bioturbation rates are used as model inputs. In conclusion, except for light congeners, soil is still a sink of PCDD/Fs present in Baltic air. However, the increase in soil/air fugacity ratios suggest an increasing important of soil-to-air transport in the near future. Equilibrium passive samplers using POM strips are considered as a very simple, reproducible, and inexpensive partitioning method. However, the largest disadvantage of using passive samplers for dioxins is the long time to reach equilibrium. It takes 6 months for PCDD/Fs to obtain equilibrium between soil and POM strips, which exceeded the time for doing a 45 credit thesis. The analytical phase of the experiment is still on-going, and thus it was not possible to include the experimental results in this study.
Książki na temat "Dioxins"
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Arnold, Schecter, i Gasiewicz Thomas A, red. Dioxins and health. Wyd. 2. New York, NY: Wiley-Interscience, 2003.
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Arnold, Schecter, i Gasiewicz Thomas A, red. Dioxins and health. Wyd. 2. New York, NY: Wiley-Interscience, 2003.
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Schecter, Arnold, red. Dioxins and Health. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4899-1462-0.
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Schecter, Arnold, i Thomas A. Gasiewicz, red. Dioxins and Health. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2003. http://dx.doi.org/10.1002/0471722014.
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Schecter, Arnold, red. Dioxins and Health. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118184141.
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Arnold, Schecter, i Gasiewicz Thomas A, red. Dioxins and health. Wyd. 2. New York, NY: Wiley-Interscience, 2003.
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Arnold, Schecter, red. Dioxins and health. New York: Plenum Press, 1994.
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Rolf-Michael, Wittich, red. Biodegradation of dioxins and furans. Berlin: Springer, 1998.
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Great Britain. Central Directorate on Environmental Pollution., red. Dioxins in the environment. London: H.M.S.O., 1989.
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Christoffer, Rappe, International Agency for Research on Cancer. i France Ministère de l'environnement, red. Polychlorinated dioxins and dibenzofurans. Lyon: International Agency for Research on Cancer, 1991.
Znajdź pełny tekst źródłaCzęści książek na temat "Dioxins"
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Brunner, Calvin R. "Dioxins". W Hazardous Air Emissions from Incineration, 54–65. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2539-0_6.
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Lu, Shengyong, Alfons Buekens, Tong Chen, Xiaoqing Lin, Mingxiu Zhan i Mengmei Zhang. "Dioxins and Dioxin-like Compounds". W Handbook on Characterization of Biomass, Biowaste and Related By-products, 1211–65. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-35020-8_13.
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Startin, James R. "Dioxins in Food". W Dioxins and Health, 115–37. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4899-1462-0_4.
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Webster, Thomas F., i Barry Commoner. "Overview: The Dioxin Debate". W Dioxins and Health, 1–53. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2005. http://dx.doi.org/10.1002/0471722014.ch1.
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Seegal, Richard F. "Effects of Polychlorinated Biphenyls on Neuronal Signaling". W Dioxins and Health, 433–55. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2005. http://dx.doi.org/10.1002/0471722014.ch10.
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Teeguarden, Justin G., i Nigel J. Walker. "Experimental Toxicology: Carcinogenesis". W Dioxins and Health, 457–90. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2005. http://dx.doi.org/10.1002/0471722014.ch11.
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Gasiewicz, Thomas A., i Sang-Ki Park. "Ah Receptor: Involvement in Toxic Responses". W Dioxins and Health, 491–532. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2005. http://dx.doi.org/10.1002/0471722014.ch12.
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Kerzee, J. Kevin, Ying Xia i Alvaro Puga. "Biochemical Responses to Dioxins: Which Genes? Which Endpoints?" W Dioxins and Health, 533–58. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2005. http://dx.doi.org/10.1002/0471722014.ch13.
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Hahn, Mark E. "Evolutionary and Physiological Perspectives on Ah Receptor Function and Dioxin Toxicity". W Dioxins and Health, 559–602. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2005. http://dx.doi.org/10.1002/0471722014.ch14.
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Tanguay, Robert L., Eric A. Andreasen, Mary K. Walker i Richard E. Peterson. "Dioxin Toxicity and Aryl Hydrocarbon Receptor Signaling in Fish". W Dioxins and Health, 603–28. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2005. http://dx.doi.org/10.1002/0471722014.ch15.
Pełny tekst źródłaStreszczenia konferencji na temat "Dioxins"
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Huwe, Janice K., i Gerald L. Larsen. "Dioxins and dioxin-like compounds in domestic meat". W Sixth International Symposium on the Epidemiology and Control of Foodborne Pathogens in Pork. Iowa State University, Digital Press, 2005. http://dx.doi.org/10.31274/safepork-180809-731.
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Gogol, Elina V., Guzel I. Gumerova i Olga S. Egrova. "Approaches to Assessment and Hazard Identification of Dioxins". W Environmental Engineering. VGTU Technika, 2017. http://dx.doi.org/10.3846/enviro.2017.021.
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In the Russian practice in the framework of environmental regulation sanitary measurements to assess the toxicity of the objects of the environment, which are based on the determination of standardized components concentrations and comparing them with the limit value, are widely used. But this approach doesn’t allow assessing the degree of biological hazards for organisms. The biotesting method has been considered for assessing the safety of dioxin-like compounds. Dioxins can be formed out of control in the environment. Ultraviolet radiation accelerates the formation of dioxins, as it enhances the ability of a chemical reaction of chlorine. This phenomenon is well known in Russia, where the chlorination is a standard procedure of water treatment and disinfection of drinking water, and control of the content of chlorophenols is an optional procedure. Simulation of the formation of dioxins in the process of chlorination of water, containing phenolic compounds, was carried out. Process of dioxins transformation in living systems to more toxic metabolites has been described. Enzymes that are involved in detoxification of dioxins have been identified. According to the results of bioassay danger of water samples, containing dioxins, is underestimated, since it doesn’t take into account specific features of metabolism of dioxins in living organisms. Under the action of enzymes in the cells the less toxic compounds can be converted into the more toxic in terms of carcinogenicity and mutagenicity. The system of determination of the dioxin toxic equivalency factor doesn’t account for it. Thus, during determination of danger of xenobiotics in living organisms we should move away from the determination of acute toxicity and focus on the processes that are started by enzyme systems when a toxicant gets into cells of living organisms.
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Yan, Jian-Hua, Sheng-Yong Lu, Yue-Ling Gu, Xu-Guang Jiang, Xiao-Dong Li i Ke-Fa Cen. "Trace Organic Pollutants Emission From Large-Scale Circulating Fluidized Bed Incinerators of Co-Firing Chinese MSW and Coal". W 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78066.
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Complex components, high moisture and low caloric value of raw Chinese MSW (Municipal Solid Waste) lead to the difficulties of keeping stable burning and low pollutant emission. Differential Density Circulated Fluidized Bed (DDCFB) incinerator was first developed by Zhejiang University to overcome such difficulties. The research of organic pollutants, especially dioxins and polycyclic aromatic hydrocarbons emission and control from MSW incinerators has been carried out in ITPE since 1998. The aim of this paper is to provide the scheme of a new co-firing CFB incineration technology, and useful data for environmental evaluation of trace organic pollutants emission from incinerators. The art of co-firing CFB is presented briefly in the first part of this paper. The dioxin content in original Chinese MSW is estimated to be 10 pg I-TEQ/g based on the data from Abad et al. Several test runs are conducted in a real-scale (150ton/day) incinerator co-firing MSW and coal to investigate dioxins and polycyclic aromatic hydrocarbons emission to ambient air. Test results show that dioxins input into the incinerator is estimated around 300∼600 mg I-TEQ/y, dioxins output is estimated 3∼100 mg I-TEQ/y, and dioxins emitted to ambient air is around 0.1∼15mg I-TEQ/y. It seemed that most of dioxins in original waste are decomposed by incineration process. For seventeen priority PAHs, its emission to ambient air is around 200∼4160g/y for co-firing runs, which is much more than 80g/y for coal combustion only. This suggests that PAHs emission to ambient air needed to be more concerned than dioxins. That is to say, PAHs emission regulatory should be proposed as soon as possible to restrict all incinerators. Several new incinerators (200 tons/day per unit and 300 tons/day per unit) were built by using new Co-firing CFB technology in past few years. From the environmental evaluation report, dioxins emission in stack gas is in range of 0.0025∼0.06 ng I-TEQ/Nm3, which seemed far below the European limit. The annual dioxin emission to air for 200ton/day or 300 t/d units is around 3∼6 mg I-TEQ. It shows that co-firing CFB incinerator is capable of reducing dioxin emission effectively. Based on industrial demonstration experience of new co-firing CFB incineration technology, it has been proven environmental friendly method for thermal treatment of MSW in developing countries. Some reasons for low dioxin emission of co-firing processes are discussed in this paper.
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Winder, C., i G. Smith. "Dioxins in remediation workers". W ENVIRONMENTAL HEALTH AND BIOMEDICINE 2011. Southampton, UK: WIT Press, 2011. http://dx.doi.org/10.2495/ehr110221.
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Themelis, N. J., i P. Deriziotis. "Substance and Perceptions of Environmental Impacts of Dioxin Emissions: An Interim Report". W 11th North American Waste-to-Energy Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/nawtec11-1690.
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The emission of dioxins is perceived widely as a major environmental impact of combustion processes. This paper will report the results of an extensive study of published data on a) the rate of formation of dioxins from all U.S. sources; b) the pre-MACT and post-MACT performance of individual Waste-to-Energy (WTE) plants in the U.S. and how post-MACT emissions compare with the 1998 EU standard (0.1 ng/dscm); c) how the contribution of WTEs has changed with time; and d) the measured impacts of WTE dioxin emissions on soil/plant concentrations and on public health. The study has shown that since 1987 the U.S. dioxin emissions have decreased by a factor of four and by now WTEs are a miniscule source. Also, that even at the earlier high emission levels, the dioxin levels in soil samples close to WTE facilities did not exhibit an increase over regional background concentrations. Finally, the paper contrasts public perceptions of the dioxin threat with scientific studies of observed effects on the environment and on public health.
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Renou-Gonnord, M. F., K. Coulibaly i F. Genet. "DIOXINS DESTRUCTION IN A FLYASH PLASMA TREATMENT". W Progress in Plasma Processing of Materials, 1999. Connecticut: Begellhouse, 2023. http://dx.doi.org/10.1615/itppc-1998.1130.
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Ma, Jianmin, Kaijie Chen, Tao Huang i Shu Tao. "Footprints of Dioxins in Global Pork Meat Trade". W Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.1678.
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Boss, M., i D. Day. "400. Building Interior Decontamination — Mercury, Biologicals, Dioxins, PCBs". W AIHce 2001. AIHA, 2001. http://dx.doi.org/10.3320/1.2765942.
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Radu, Tamara. "DIOXINS AND FURANS EMISSIONS IN THE PRIMARY STEEL SECTOR". W 13th SGEM GeoConference on ENERGY AND CLEAN TECHNOLOGIES. Stef92 Technology, 2013. http://dx.doi.org/10.5593/sgem2013/bd4/s19.013.
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MASCINI, M., I. COZZANI, D. COMPAGNONE, A. MACAGNANO, C. DI NATALE, A. D'AMICO, D. MONTI, R. PAOLESSE, B. CHEN i P. WARNER. "BIOMIMETIC TRAPS FOR DIOXINS: A MIXED COMPUTATIONAL AND EXPERIMENTAL APPROACH". W Proceedings of the 8th Italian Conference. WORLD SCIENTIFIC, 2004. http://dx.doi.org/10.1142/9789812702944_0012.
Pełny tekst źródłaRaporty organizacyjne na temat "Dioxins"
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Elbers, I. J. W., Guillaume ten Dam, D. P. K. H. Pereboom i W. C. M. de Nijs. Proficiency test for dioxins, dioxin-like PCBs and non-dioxin-like PCbs in feed oil. Wageningen: RIKILT Wageningen University & Research, 2018. http://dx.doi.org/10.18174/462577.
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Michael J. Coggiola, Harald Oser, Gregory W. Faris i David R. Crosley. Initial Development of a Continuous Emission Monitor for Dioxins. Office of Scientific and Technical Information (OSTI), marzec 2002. http://dx.doi.org/10.2172/897544.
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ADAMS, J. W., P. D. KALB i D. B. MALKMUS. SEPRADYNE/REDUCE HIGH VACUUM THERMAL PROCESS FOR DESTRUCTION OF DIOXINS IN INEEL/WERF FLY ASH. Office of Scientific and Technical Information (OSTI), sierpień 1999. http://dx.doi.org/10.2172/896195.
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ADAMS, J. W., P. D. KALB i D. B. MALKMUS. SEPRADYNE/RADUCE HIGH VACUUM THERMAL PROCESS FOR DESTRUCTION OF DIOXINS IN INEEL/WERF FLY ASH. Office of Scientific and Technical Information (OSTI), sierpień 1999. http://dx.doi.org/10.2172/782680.
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Word, J. Q., J. A. Ward i A. L. Squires. Results of chemical, toxicological, and bioaccumulation evaluations of dioxins, furans, and guaicol/organic acids in sediments from the Grays Harbor/Chehalis River area. Office of Scientific and Technical Information (OSTI), wrzesień 1990. http://dx.doi.org/10.2172/6364326.
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Bansel, Prateek, Rubal Dua, Rico Krueger i Daniel Graham. Are Consumers Myopic About Future Fuel Costs? Insights from the Indian two-wheeler market. King Abdullah Petroleum Studies and Research Center, sierpień 2021. http://dx.doi.org/10.30573/ks--2021-dp13.
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India has the world’s third highest carbon dioxide (CO2) emissions, after China and the United States. The transportation sector is the third largest contributor to carbon dioxide emissions in India, accounting for roughly 11% of all carbon dioxide emissions in 2016. Road transport accounts for around 94% of the total carbon dioxide emissions of the transportation sector.
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Skone, Timothy J. Carbon Dioxide Dehydration. Office of Scientific and Technical Information (OSTI), listopad 2012. http://dx.doi.org/10.2172/1509004.
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Figueroa, Javier, i Mark Williamson. Uranium Dioxide Conversion. Office of Scientific and Technical Information (OSTI), wrzesień 2014. http://dx.doi.org/10.2172/1159227.
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Martin, Olga. Carbon Dioxide Decomposition. Office of Scientific and Technical Information (OSTI), październik 2012. http://dx.doi.org/10.2172/1054236.
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Gerth, Wayne A. Chamber Carbon Dioxide and Ventilation. Fort Belvoir, VA: Defense Technical Information Center, listopad 2004. http://dx.doi.org/10.21236/ada442939.
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