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Effect of dietary and environmental endocrine disruptors on estrogen metabolic enzyme expression. / CUHK electronic theses & dissertations collectionJanuary 2009 (has links)
Because of the structural resemblance to the female hormone, phytoestrogen is another important class of endocrine disruptor. In the present project, we evaluated the effects of phytoestrogens isoliquiritigenin (ILN), hesperetin (HES), genistein, (GEN) and naringenin (NAR) on estrogen metabolism and also their effects on MCF-7 tumor growth in ovariectomized nude mice. We found that these phytoestrogens had differential effect on MCF-7 xenografts. NAR and GEN had totally different responses in the tumor growth. In contrast, ILN and HES only deterred MCF-7 xenograft growth when CYP19 was overexpressed in the graft. / Breast cancer is one of the most prevalent female cancers in Hong Kong and western countries. Prolonged exposure to estrogen has been associated with increased risk of breast cancer. Many enzymes are responsible for estrogen metabolism, for instance, aromatase (CYP19) is responsible for biosynthesis; CYP1 family enzymes hydroxylate estrogen; COMT (catechol-O-methyltransferase) inactivates the hydroxyestrogen; and UDP-glucuronosyltransferase 1A1 (UGT1A1) eliminates the estrogen metabolites. In this project, we employed cell and animal models to address estrogen metabolism-related questions under the influence of endocrine disruptors. / TCDD is a prototype compound of a whole class of halogenated aromatic hydrocarbons termed dioxin-like contaminants, which are also known to be endocrine disruptors. Because of their persistence in the environment dioxins are one of the most concerned classes of carcinogens. Humans can be exposed to this pollutant through contaminated food, air, drinking water, etc. We found that pre-ovariectomy administration of TCDD could significantly reduce aromatase expression in the brain but increase the expression in the adipose tissue. Our results suggested that the timing of exposure to the toxicant could determine the estrogenicity of TCDD. / The present project indicated that endocrine disruptors can alter the metabolism of estrogen; however, the significance of this alteration may be specific to tissues' phenotype and the timing of exposure. / Ye Lan. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 169-192). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
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Estudo sobre desruptores endócrinos em sistemas aquáticos : detecção e perspectivas de tratamento das águas do Rio Aporé-MS/GO, utilizando-se adsorventes sólidos /Garcia, Edemir Feliciano. January 2014 (has links)
Orientador: Newton Luiz Dias Filho / Banca: Enes Furlani Junior / Banca: André Rodrigues dos Reis / Banca: Edemar Benedetti Filho / Banca: Gilberto José de Arruda / Resumo: Desruptoress endócrinos (D.E), como por exemplo, os pesticidas, representam uma classe emergente de contaminantes em sistemas aquáticos, que pode comprometer a vida da biota aquática e de seres humanos. Embora alguns estudos estejam sendo desenvolvidos no sentido de quantificação e verificação da toxicidade dos D.E presentes no ambiente, praticamente não há na literatura registros de estudos associados ao comportamento e disponibilidade destas substâncias em águas superficiais. Este trabalho buscou determinar a presença dos herbicidas 2,4-D(ácido 2,4-diclorofenoxiacético), Atrazina e Linuron e do inseticida Paration Metil, considerados D.E pela literatura internacional, nas águas do Rio Aporé e propor perspectivas de tratamento de águas de sistemas hídricos por meio de adsorventes sólidos de baixo custo. Este rio está localizado no cerrado brasileiro, o qual é marco divisor do Estado de Mato Grosso do Sul com o Estado de Goiás e recebe grande carga de resíduos de produção agrícola. Após a coleta de amostras de água em pontos estratégicos, foi feita extração pela técnica de Extração em Fase Sólida, em cartuchos de sílica C-18 e a detecção em Cromatografia Gasosa acoplada com detector de Espectrometria de Massas. Os materiais testados para a remoção dos pesticidas alvo deste trabalho foram obtidos a partir de: i) argila organicamente modificada com o surfactante N-dodecil-2-pirrolidona (Mo-DDP); ii) garrafas de PET pós uso (PET); III) biomassa de pinhão manso - J. curcas L. (TPMAN); iv) cinzas de casca de arroz (CCA); v) sílica gel organicamente modificada com 2-Amino-1,3,4- thiadiazol (SGT) e vi) carvão ativado a partir de casca de coco (CA). Os estudos de detecção e quantificação dos pesticidas nas águas do Rio Aporé demonstraram a presença dos pesticidas Malation e Dibutilftalato, os quais são considerados D.E por órgãos governamentais brasileiro,... / Abstract: Endocrine disrupters chemical (EDC), such as pesticides, represent an emerging class of contaminants in aquatic systems that can compromise the life of aquatic biota and human. Although some studies are being developed to quantify and verify the toxicity of EDC in the environment, there is almost no literature records related to the conduct studies and availability of these substances in surface waters. The aim of this study was to verity the presence of herbicide 2,4-D (diclorfenoxacetic acid), Atrazine and Linuron and insecticide Methyl Paration in Aporé River to propose perspectives of treatment in these waters by using low cost adsorbents. This river is located at the Brazilian savanna region, river that is located between Mato Grosso do Sul state and Goias state and receives a great amount of agricultural production waste. After collecting an amount of water at strategic points, has been done an extraction by the technical of Solid Phase Extraction, in cartridges of silica C-18, the detection in Gas Chromatography, attached with a detector Mass Spectrometry. The materials tested for the removal of pesticides, targeted in this study, were obtained from the: i) organically modified clays with surfactant N-dodecyl-2-pyrrolidone (Mo-DDP); ii) PET- Polyethylene terephthalate bottle after use (PET); III) biomass of J. curcas L. (TPMAN); iv) rice husk ash (RHA); v) silica gel organically modified with 2-Amino-1,3,4-thiadiazole (SGT) and vi) activated carbon from coconut shell (AC). Studies of detection and quantification of pesticides on the Aporé River's water demonstrate the presence of pesticides Malathion and Dibutyl phthalate(DBP), which are considered EDC by Brazilian, American and European government agencies. The adsorbents used had positive parameters to use for removal of these molecules, both in batch studies when fixed bed. The adsorption parameters tested showed that 60 to 120 min. ... / Doutor
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Gene Expression Changes in Prostate Cells upon Exposure to Environmental Anti-androgenic Pesticide VinclozolinPrasad, Saurabh 01 October 2012 (has links)
Vinclozolin (VCZ), an antiandrogenic fungicide, is an endocrine disrupting chemical that is known to possess high affinity for the androgen receptor (AR) and modulate expression of critical androgen-dependant genes in the prostate. In this study, viability and expression of AR, NKX3.1 and CYP3A4 genes were measured in androgen-sensitive prostate cells LNCaP after exposure to VCZ and VCZ treated with S9 microsomes in a time and dose dependent manner. NKX3.1 is an androgen regulated gene that plays a vital role in prostate development. CYP3A4 is involved in xenobiotic metabolism. VCZ decreased the viability at high doses after 48 hours which was slightly mitigated by treatment with S9 metabolites. Expression of NKX3.1 and CYP3A4 was upregulated while an initial downregulation of AR was observed. NKX3.1 upregulation corroborates with possibility of antiandrogens to act as androgens in LNCaP. The results illustrate that VCZ can interfere with the expression of critical prostate genes.
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Chronic effects of single intra-peritoneal injection of endosulfan on rainbow trout (Oncorhynchus mykiss) and field observations of caged rainbow in Oshawa CreekArmour, Jeffrey Andrew 01 August 2009 (has links)
The organochlorine pesticide endosulfan has been shown to be highly toxic to fish
and there is some evidence to support that it may act as an endocrine disrupting chemical.
Juvenile rainbow trout (Oncorhynchus mykiss) were caged at 4 sites in Oshawa Creek
during the fall and spring of 2008 and 2009 while another group was intra-peritoneal
injected in the laboratory with varying concentrations (ppm) of endosulfan. Plasma
vitellogenin (VTG) levels, liver ethoxyresorufin-O-deethylase (EROD), citrate synthase
(CS), lactate dehydrogenase (LDH), and brain acetylcholine esterase (AChE) (caged fish
only) enzymatic activities were measured. Trout injected with endosulfan experienced an
increase of the anaerobic (LDH activity) and a decrease of the aerobic (CS activity)
metabolic pathways, while male VTG levels increased. Since it was a singular injection,
VTG results have to be confirmed. Fall caged trout showed increased EROD activity and
inhibited AChE activity while those caged in the spring experienced an unexpected
exposure to the lampricide 3-Trifluoro-Methyl-4-Nitro-Phenol (TFM) which disrupted
metabolic parameters (inhibited CS and increased LDH activity). Both fall and spring
caged trout experienced no induction of VTG activity. Further research is needed since
the spring exposure was altered due to the unplanned TFM treatment and thus did not
represent a valid temporal replicate.
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Analysis of Selected Pharmaceuticals and Endocrine Disrupting Compounds and their Removal by Granular Activated Carbon in Drinking Water TreatmentYu, Zirui January 2007 (has links)
Over the last decade, endocrine disrupting compounds (EDCs) and pharmaceutically active compounds (PhACs) have been detected in drinking water at very low levels, mostly ng/L concentrations, suggesting that these compounds resisted removal through water treatment processes. Concerns have been raised regarding the effectiveness of common drinking water treatment technologies to remove these emerging contaminants. Adsorption processes were suggested to play an important role in the removal of PhACs and EDCs, based on the assumption that these compounds are similar to other conventional micropollutants such as pesticides in both physicochemical properties and concentration levels present in water. However, this remains to be demonstrated since the availability of adsorption data for PhACs and EDCs is extremely limited and their environmental concentrations are typically much lower than the ones for pesticides. The primary objective of this research was to evaluate in detail the removal of representative EDCs and PhACs at environmentally relevant concentrations by granular activated carbon (GAC) adsorption.
In the first stage of this study, EDCs (15) were screened separately from the PhACs (86) with two different sets of assessment criteria due to the different nature and the availability of information for these two groups of compounds. As a result, 6 EDCs and 12 PhACs were selected for further evaluation. Subsequently, a multi-residue analytical method based on gas chromatography/mass spectrometry (GC/MS) was developed for the simultaneous determination of the selected PhACs and EDCs. Two key analytical steps - solid phase extraction and derivatization - were systematically optimized using full factorial design and a central composite design, respectively. The statistical experimental design in combination with the concept of the total desirability was demonstrated to be an effective tool for developing a multi-residue analytical method. The application of the developed method to Grand River water, a local raw water source, and finished drinking water from this source indicated that PhACs such as naproxen, carbamazepine, salicylic acid, ibuprofen, and gemfibrozil, and EDCs such as estrone (E1) and nonylphenol mono-ethoxy carboxylate (NP1EC) were the most common contaminants. Based on these results, the quality of the analytical data, and the physicochemical properties relevant to the adsorption on activated carbon, two PhACs (naproxen, carbamazepine) and one EDC (nonylphenol (NP)) were finally chosen for the adsorption studies.
Adsorptions of the selected target compounds were evaluated on two types of activated carbon (coal-based Calgon Filtrasorb® 400 (F400) and coconut shell-based PICACTIF TE (PICA) by first investigating their isotherms at environmentally relevant concentrations (equilibrium liquid phase concentration ranging from 10 to 1000 ng/L). The single-solute isotherm data determined for both carbons showed that the relative adsorbabilities of the three target compounds were not in agreement with expectations based on their log Kow values. Overall, in this low concentration range, carbamazepine was most easily removed, and NP was least adsorbable. The adsorption of naproxen was negatively influenced by its dissociation in water. Comparison of single-solute isotherms on F400 carbon for the target compounds to those for other selected conventional micropollutants showed that naproxen and carbamazepine have generally comparable isotherms to 2-methylisoborneol (MIB) and geosmin. The isotherm tests in a post-sedimentation (PS) water from a full-scale plant demonstrated that the presence of background natural organic matter (NOM) significantly reduced the adsorption of all three target compounds, among which.NP was the least impacted compound. Based on the quantification of the direct competition using the ideal adsorbed solution theory (IAST) in combination with the equivalent background compound (EBC) approach, the minimum carbon usage rates (CURs) for removing 90% of the target compounds in PS water were calculated at two environmentally relevant concentrations (50 and 500 ng/L). This work confirmed that the percentage removal of the trace level target compound at a given carbon dosage was independent of the initial target compound concentration.
Isotherm experiments were conducted for the target compound on GACs preloaded with PS water for various time intervals (up to 16 weeks) at the Mannheim Water Treatment Plant (Region of Waterloo, ON, Canada). The results indicated that the adsorption of all target compounds were subject to significant negative impacts from preloading of NOM, albeit to different extents. Among the three target compounds, reduction in adsorption capacity for naproxen was most severe, followed by carbamazepine and then NP. The three target compounds followed quite different patterns of decrease in adsorption capacity with increasing preloading time, thus revealing different competitive mechanisms at work for the different compounds. For naproxen, the change in heterogeneity of the carbons due to preloading suggests that some pre-adsorbed NOM could not be replaced by naproxen. However, both direct competitive and pore blockage mechanisms could successfully explain the adsorption performance of naproxen and carbamazepine. The removal of NP even at prolonged preloading times could be explained by absorption or partitioning in the NOM matrix on the surface of, or inside the carbons.
The kinetic parameters for each target compound-virgin carbon pair were determined using the short fixed bed (SFB) approach based on the pore and surface diffusion model (PSDM). The SFB results and sensitivity analyses indicated that, under the very low influent concentration conditions, film diffusion (indexed as βL) exerts a much greater effect on breakthrough profiles than internal diffusion. The SFB tests on preloaded GACs showed that mass transport of all the target compounds decreased with increasing preloading time. Similar to the impact of preloading on adsorption capacity, naproxen was subject to the most deteriorative effect, followed by carbamazepine and then NP. In addition, potential mechanisms for the decay of the film diffusion coefficient with increased preloading time were discussed based on scanning electron microscope (SEM) images of virgin and preloaded GAC. Electrostatic interactions between the NOM/bio film formed on the preloaded carbon and dissociated naproxen may have contributed to the enhanced reduction in its film diffusion. Sensitivity analyses and subsequent calculations of the Biot numbers confirmed that film diffusion was also the predominant mechanism controlling the mass transport on preloaded carbon, in particular for naproxen. This suggests that the early breakthrough prediction of the target compounds at their environmentally relevant concentrations could be further simplified by only considering film diffusion and adsorptive capacity.
Kinetic and isotherm parameters were used as input for modeling using time-variable PSDM. It was found that the varying trends for Freundlich KF and 1/n, and βL could be generally depicted by a corresponding empirical model. Pilot scale treatability tests were performed for the target compounds which subsequently validated the time-variable PSDM results thus demonstrating its effectiveness and robustness to model GAC adsorber performance for PhAC and EDC removal at environmentally relevant concentrations. The time-variable approach was further improved by adjusting for NOM surface loading differences between the preloading and the pilot columns, which successfully compensated for the prediction errors at the early phase.
The validated NOM surface loading associated time variable PSDM was used to predict performances of hypothetical F400 and PICA full-scale adsorbers. Both adsorbers were expected to provide satisfactory performance in achieving 90% removals for the neutral target compounds (carbamazepine and NP). Naproxen was predicted to break through fast since both, capacity and kinetic parameters decay quickly due to carbon fouling by NOM and the physicochemical properties of this compound. Initial recommendations on the choice of adsorption process (GAC vs. PAC) for removing EDCs and PhACs can be made based on the comparison of carbon usage rates (CUR) which were calculated for a GAC adsorber using the validated improved PSDM and for PAC using the minimum applied dosages predicted by the IAST-EBC model.
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Analysis of Selected Pharmaceuticals and Endocrine Disrupting Compounds and their Removal by Granular Activated Carbon in Drinking Water TreatmentYu, Zirui January 2007 (has links)
Over the last decade, endocrine disrupting compounds (EDCs) and pharmaceutically active compounds (PhACs) have been detected in drinking water at very low levels, mostly ng/L concentrations, suggesting that these compounds resisted removal through water treatment processes. Concerns have been raised regarding the effectiveness of common drinking water treatment technologies to remove these emerging contaminants. Adsorption processes were suggested to play an important role in the removal of PhACs and EDCs, based on the assumption that these compounds are similar to other conventional micropollutants such as pesticides in both physicochemical properties and concentration levels present in water. However, this remains to be demonstrated since the availability of adsorption data for PhACs and EDCs is extremely limited and their environmental concentrations are typically much lower than the ones for pesticides. The primary objective of this research was to evaluate in detail the removal of representative EDCs and PhACs at environmentally relevant concentrations by granular activated carbon (GAC) adsorption.
In the first stage of this study, EDCs (15) were screened separately from the PhACs (86) with two different sets of assessment criteria due to the different nature and the availability of information for these two groups of compounds. As a result, 6 EDCs and 12 PhACs were selected for further evaluation. Subsequently, a multi-residue analytical method based on gas chromatography/mass spectrometry (GC/MS) was developed for the simultaneous determination of the selected PhACs and EDCs. Two key analytical steps - solid phase extraction and derivatization - were systematically optimized using full factorial design and a central composite design, respectively. The statistical experimental design in combination with the concept of the total desirability was demonstrated to be an effective tool for developing a multi-residue analytical method. The application of the developed method to Grand River water, a local raw water source, and finished drinking water from this source indicated that PhACs such as naproxen, carbamazepine, salicylic acid, ibuprofen, and gemfibrozil, and EDCs such as estrone (E1) and nonylphenol mono-ethoxy carboxylate (NP1EC) were the most common contaminants. Based on these results, the quality of the analytical data, and the physicochemical properties relevant to the adsorption on activated carbon, two PhACs (naproxen, carbamazepine) and one EDC (nonylphenol (NP)) were finally chosen for the adsorption studies.
Adsorptions of the selected target compounds were evaluated on two types of activated carbon (coal-based Calgon Filtrasorb® 400 (F400) and coconut shell-based PICACTIF TE (PICA) by first investigating their isotherms at environmentally relevant concentrations (equilibrium liquid phase concentration ranging from 10 to 1000 ng/L). The single-solute isotherm data determined for both carbons showed that the relative adsorbabilities of the three target compounds were not in agreement with expectations based on their log Kow values. Overall, in this low concentration range, carbamazepine was most easily removed, and NP was least adsorbable. The adsorption of naproxen was negatively influenced by its dissociation in water. Comparison of single-solute isotherms on F400 carbon for the target compounds to those for other selected conventional micropollutants showed that naproxen and carbamazepine have generally comparable isotherms to 2-methylisoborneol (MIB) and geosmin. The isotherm tests in a post-sedimentation (PS) water from a full-scale plant demonstrated that the presence of background natural organic matter (NOM) significantly reduced the adsorption of all three target compounds, among which.NP was the least impacted compound. Based on the quantification of the direct competition using the ideal adsorbed solution theory (IAST) in combination with the equivalent background compound (EBC) approach, the minimum carbon usage rates (CURs) for removing 90% of the target compounds in PS water were calculated at two environmentally relevant concentrations (50 and 500 ng/L). This work confirmed that the percentage removal of the trace level target compound at a given carbon dosage was independent of the initial target compound concentration.
Isotherm experiments were conducted for the target compound on GACs preloaded with PS water for various time intervals (up to 16 weeks) at the Mannheim Water Treatment Plant (Region of Waterloo, ON, Canada). The results indicated that the adsorption of all target compounds were subject to significant negative impacts from preloading of NOM, albeit to different extents. Among the three target compounds, reduction in adsorption capacity for naproxen was most severe, followed by carbamazepine and then NP. The three target compounds followed quite different patterns of decrease in adsorption capacity with increasing preloading time, thus revealing different competitive mechanisms at work for the different compounds. For naproxen, the change in heterogeneity of the carbons due to preloading suggests that some pre-adsorbed NOM could not be replaced by naproxen. However, both direct competitive and pore blockage mechanisms could successfully explain the adsorption performance of naproxen and carbamazepine. The removal of NP even at prolonged preloading times could be explained by absorption or partitioning in the NOM matrix on the surface of, or inside the carbons.
The kinetic parameters for each target compound-virgin carbon pair were determined using the short fixed bed (SFB) approach based on the pore and surface diffusion model (PSDM). The SFB results and sensitivity analyses indicated that, under the very low influent concentration conditions, film diffusion (indexed as βL) exerts a much greater effect on breakthrough profiles than internal diffusion. The SFB tests on preloaded GACs showed that mass transport of all the target compounds decreased with increasing preloading time. Similar to the impact of preloading on adsorption capacity, naproxen was subject to the most deteriorative effect, followed by carbamazepine and then NP. In addition, potential mechanisms for the decay of the film diffusion coefficient with increased preloading time were discussed based on scanning electron microscope (SEM) images of virgin and preloaded GAC. Electrostatic interactions between the NOM/bio film formed on the preloaded carbon and dissociated naproxen may have contributed to the enhanced reduction in its film diffusion. Sensitivity analyses and subsequent calculations of the Biot numbers confirmed that film diffusion was also the predominant mechanism controlling the mass transport on preloaded carbon, in particular for naproxen. This suggests that the early breakthrough prediction of the target compounds at their environmentally relevant concentrations could be further simplified by only considering film diffusion and adsorptive capacity.
Kinetic and isotherm parameters were used as input for modeling using time-variable PSDM. It was found that the varying trends for Freundlich KF and 1/n, and βL could be generally depicted by a corresponding empirical model. Pilot scale treatability tests were performed for the target compounds which subsequently validated the time-variable PSDM results thus demonstrating its effectiveness and robustness to model GAC adsorber performance for PhAC and EDC removal at environmentally relevant concentrations. The time-variable approach was further improved by adjusting for NOM surface loading differences between the preloading and the pilot columns, which successfully compensated for the prediction errors at the early phase.
The validated NOM surface loading associated time variable PSDM was used to predict performances of hypothetical F400 and PICA full-scale adsorbers. Both adsorbers were expected to provide satisfactory performance in achieving 90% removals for the neutral target compounds (carbamazepine and NP). Naproxen was predicted to break through fast since both, capacity and kinetic parameters decay quickly due to carbon fouling by NOM and the physicochemical properties of this compound. Initial recommendations on the choice of adsorption process (GAC vs. PAC) for removing EDCs and PhACs can be made based on the comparison of carbon usage rates (CUR) which were calculated for a GAC adsorber using the validated improved PSDM and for PAC using the minimum applied dosages predicted by the IAST-EBC model.
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Integrative analysis of endocrine-disrupting chemical effects in the developing hypothalamus : adult behaviors and neural networksTopper, Viktoria Yuryevna 12 August 2015 (has links)
Endocrine-disrupting chemicals (EDCs) are environmental pollutants known to perturb hormone systems and interfere with normal endocrine function. Exposure to EDCs during hormone-sensitive developmental periods can result in profound dysfunction in reproductive physiology and behavior. In this dissertation, effects of gestational exposure to a class of EDCs called polychlorinated biphenyls (PCBs) were examined in the developing hypothalamus, which is known to control reproductive physiology and behavior in vertebrates. The specific hypothesis was that PCBs caused changes in sexually dimorphic hypothalamic nuclei, resulting in perturbation of adult sociosexual behaviors and alteration of neural networks with changes in expression of microRNAs and genes during development and in adulthood.
This research focused on two brain areas relevant to understanding the PCB effects on the developing hypothalamus: 1) microRNA and related target gene expression during postnatal development, 2) adult sociosexual behaviors and gene expression. In both sections, molecular changes were examined in two sexually dimorphic hypothalamic nuclei, medial preoptic nucleus (MPN) and ventromedial nucleus (VMN), known for their role in regulation of sociosexual behavior. In the first section of the dissertation, the effects of PCBs were examined on the expression of microRNAs and target genes at four ages during postnatal [P] development (P15, P30, P45, and P90). Age and sex specific effects were observed in both MPN and VMN, with greater effects in the MPN. The second research section of the dissertation explored whether sociosexual behaviors, namely ultrasonic vocalizations and sociosexual preference behaviors, were altered by gestational PCBs. Expression of forty-eight neuroendocrine candidate genes was also examined in the MPN and VMN of the same animals. Several sociosexual behaviors were affected, including number and acoustic properties of ultrasonic vocalizations, and nose-touching with opposite-sex animals. Gene expression was altered in sex and region-specific manner in the brains of behaviorally affected rats. Taken together, these findings suggest that gestational PCBs have lasting effects on molecular mechanisms during postnatal development and in adulthood, and could result in altered sociosexual behavior. These results have implications for human health and disease, as early life exposures to EDCs have been linked to reproductive decline in humans. / text
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Investigation of endocrine disrupting compounds in membrane bioreactor and UV processesYang, Wenbo 12 January 2010 (has links)
Endocrine disrupting compounds (EDCs) in the environment have recently emerged as a major issue in Canada and around the globe. The primary objective of this thesis was to investigate the fate of EDCs in two wastewater treatment processes, membrane bioreactors (MBRs) and ultraviolet (UV) disinfection. Two submerged MBR systems using hollow fiber membranes from two membrane manufacturers were tested. The results from a bench-scale and a pilot scale MBR for the treatment of swine wastewater with high concentration of EDCs showed that over 94% of the estrogenic activity (EA) in the influent was reduced through the MBR process. Biological degradation was the dominant removal mechanism for the removal of EDCs in MBRs. Over 85% of the influent EA was reduced by biodegradation through the MBR process. The other MBR system was built to study the removal mechanisms of two estrogens in a hybrid MBR with the addition of powdered activated carbon (PAC). The effects of PAC dosing on MBR overall performance was studied as well. It was found that PAC dosing could increase the removal rates of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) by 3.4% and 15.8%, respectively and result in a slower rate of trans-membrane pressure (TMP) increase during MBR operation, which could significantly reduce the operating cost for membrane cleaning and/or replacement. The operating cost for PAC dosing could be offset by the benefit achieved from reducing the cost for membrane maintenance. The slower rate of TMP increase in the PAC-MBR was associated with the lower concentrations of soluble extracellular polymeric substances and colloidal organic compounds in the PAC-MBR sludge.
The degradation kinetics of three estrogens, estrone (E1), E2, and EE2 in de-ionized water by UV irradiation was studied. The experimental results showed both the apparent concentrations and overall EA of all three investigated estrogens in water decreased with direct UV irradiation. To further study the impact of UV on the overall EA of wastewater, the EA of pre-UV and post-UV samples from five wastewater treatment plants were measured in both liquid and solid phase by Yeast Estrogen Screen assay. It was found that the EA of wastewater decreased after UV disinfection in three of the investigated plants whereas it increased in the other two plants. This observation needs to be further studied because it might have significant impacts on the application of UV systems for wastewater disinfection.
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Investigation of endocrine disrupting compounds in membrane bioreactor and UV processesYang, Wenbo 12 January 2010 (has links)
Endocrine disrupting compounds (EDCs) in the environment have recently emerged as a major issue in Canada and around the globe. The primary objective of this thesis was to investigate the fate of EDCs in two wastewater treatment processes, membrane bioreactors (MBRs) and ultraviolet (UV) disinfection. Two submerged MBR systems using hollow fiber membranes from two membrane manufacturers were tested. The results from a bench-scale and a pilot scale MBR for the treatment of swine wastewater with high concentration of EDCs showed that over 94% of the estrogenic activity (EA) in the influent was reduced through the MBR process. Biological degradation was the dominant removal mechanism for the removal of EDCs in MBRs. Over 85% of the influent EA was reduced by biodegradation through the MBR process. The other MBR system was built to study the removal mechanisms of two estrogens in a hybrid MBR with the addition of powdered activated carbon (PAC). The effects of PAC dosing on MBR overall performance was studied as well. It was found that PAC dosing could increase the removal rates of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) by 3.4% and 15.8%, respectively and result in a slower rate of trans-membrane pressure (TMP) increase during MBR operation, which could significantly reduce the operating cost for membrane cleaning and/or replacement. The operating cost for PAC dosing could be offset by the benefit achieved from reducing the cost for membrane maintenance. The slower rate of TMP increase in the PAC-MBR was associated with the lower concentrations of soluble extracellular polymeric substances and colloidal organic compounds in the PAC-MBR sludge.
The degradation kinetics of three estrogens, estrone (E1), E2, and EE2 in de-ionized water by UV irradiation was studied. The experimental results showed both the apparent concentrations and overall EA of all three investigated estrogens in water decreased with direct UV irradiation. To further study the impact of UV on the overall EA of wastewater, the EA of pre-UV and post-UV samples from five wastewater treatment plants were measured in both liquid and solid phase by Yeast Estrogen Screen assay. It was found that the EA of wastewater decreased after UV disinfection in three of the investigated plants whereas it increased in the other two plants. This observation needs to be further studied because it might have significant impacts on the application of UV systems for wastewater disinfection.
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Fate and transport of selected endocrine disrupting chemicals in recycled water through a tropical soilMohanty, Sanjay K January 2006 (has links)
Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 131-144). / xiv, 144 leaves, bound ill. 29 cm
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