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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Characterization and Modeling of Selected Antiandrogens and Pharmaceuticals in Highly Impacted Reaches of Grand River Watershed in Southern Ontario

Arlos, Maricor Jane January 2013 (has links)
Endocrine disruption and high occurrences of intersex have been observed in wild fish associated with wastewater treatment plant (WWTP) effluents in the urbanized reaches of the Grand River watershed located in southern Ontario, Canada. WWTP effluent is a complex matrix with diverse aquatic environmental contaminants and stressors. This study aimed to: (1) characterize the spatio-temporal distribution and fate of antiandrogenic personal care products (triclosan, chlorophene, and dichlorophene), along with selected pharmaceuticals (carbamazepine, ibuprofen, naproxen, and venlafaxine) and the herbicide, atrazine in the Grand River watershed and (2) model the behaviour of these contaminants in the aquatic environment. Water sampling of 29 sites which covered six municipal WWTPs and ~100 km of river length was completed during summer low flows (July 2012). Monthly samples were also collected immediately upstream and downstream of a major WWTP (Kitchener) from August to November 2012. Many of the target pharmaceuticals and triclosan were detected in WWTP effluents in the Grand River watershed, especially those that did not nitrify (minimal treatment with high ammonia). Chlorophene was either undetected or was only found at trace levels in the effluents. Under low flow conditions, triclosan and several other pharmaceuticals exhibited a spatial pattern where concentrations increased directly downstream of the WWTPs, then decreased with distance downstream (dilution and/or degradation). Chlorophene, in contrast, was not found downstream of most of the WWTP outfalls but was first detected at a site 5 km upstream of a WWTP and then continued with relatively constant concentrations for approximately 29 km downstream. It was also only found during the summer sampling period. Atrazine was consistently found in all sampling locations which reflected the agricultural non-point source nature of this compound. The WASP 7.5 model (US Environmental Protection Agency) was adapted and calibrated to a reach of the Grand River associated with the Kitchener WWTP. The simulation of the fate and transport of the target compounds revealed that flow-driven transport processes (advection and dispersion) greatly influence their behaviour in the aquatic environment. However, fate mechanisms such as biodegradation and photolysis also potentially play an important role in the attenuation of most compounds. The exception was carbamazepine where it was shown to act as a conservative tracer compound for wastewater specific contaminants in the water phase. The fate model developed can be applied in the future to predict the fate of a wide variety of contaminants of emerging concern across the watershed to help define the exposure of these biologically active chemicals to sensitive ecosystems.
52

Treatment of Endocrine Disrupting Chemicals (EDCs) by Constructed Wetlands

Zen, Yi-peng 15 July 2010 (has links)
Alkylphenol polyethoxylates (APEOs), a class of nonionic surfactants, have been widely used for industrial, agricultural and household applications. The biodegradation metabolites of APEOs, such as nonylphenol and octylphenol, are more persistent and known to disrupt endocrine function in wildlife and human. These compounds are also recognized as endocrine disrupting chemicals (EDCs). The objectives of this study were to investigate the distribution and removal efficiencies of EDCs, including nonylphenol diethoxylates (NP2EO), nonylphenol monoethoxylates (NP1EO), nonylphenol (NP) and octylphenol (OP), of wastewater treated by the constructed wetland systems along the Dahan River and around the Dapeng Bay, respectively. In addition, the method of risk quotient was used to evaluate the potential ecological risk of APEOs to aquatic organisms in current study. The water samples collected from 32 sampling sites in the Dapeng Bay National Scenic Area including Datan, Pengcun and Linbain right bank constructed wetlands. The samples were then concentrated by solid phase extraction, and analyzed for target compounds by HPLC/fluorescence. According to the results, nonylphenol diethoxylates, nonylphenol monoethoxylates, nonylphenol and octylphenol were found approximately equal to 29.9, 47.3, 20.5 and 57.7 %, respectively of the samples from three constructed wetlands with concentrations ranged from <3.3 to 968.7, <3.3 to 226.5, <1.3 to 238.4 and <1.0 to 1458.7 ng/L, respectively. Temporal variation of APEOs showed a decreasing in the order of summer¡Öspring¡Öwinter¡Öautumn. The removal efficiencies of APEOs in these constructed wetlands showed a decreasing order of Datan wetland¡ÖPengcun wetland¡ÖLinbain right bank wetland. In addition, the samples collected from 18 sampling sites from the constructed wetlands along the riparian of Dahan River including Daniaopi, Hsin-Hai Bridge Phases I and II constructed wetlands. According to the results, nonylphenol diethoxylates, nonylphenol monoethoxylates, nonylphenol and octylphenol were found approximately equal to 91.9¡B84.8¡B17.1 and 73.7 %, respectively of samples collected from three constructed wetlands with concentrations ranged from <3.3 to 11191.5, <3.3 to 6069.0, <1.3 to 671.0 and <1.0 to 5581.9 ng/L, respectively. The removal potential of APEOs in these constructed wetlands showed a decreasing order of Hsin-Hai Bridge Phases II¡ÖDaniaopi¡ÖHsin-Hai Bridge Phases I constructed wetland. Regarding the ecological assessment in this research, the calculated risk quotients were up to 30 times higher in the constructed wetland systems of Dahan River than those in the Dapeng Bay National Scenic Area, indicating that the existing concentrations of these EDCs in wetland systems might cause potential ecological risks to aquatic organisms. Furthermore, the decreasing risk quotient from influent to effluent indicating the capabilities of treating alkylphenolic compounds in these constructed wetlands.
53

Anaerobic Membrane Bioreactor (AnMBR) for Treatment of Landfill Leachate and Removal of Micropollutants

Do, Anh Tien 01 January 2011 (has links)
To date, most studies on the fate and removal of endocrine disrupting compounds (EDCs) and pharmaceutical and personal care products (PPCPs) in wastewater focus on their fate in municipal wastewater treatment plants, and mostly under aerobic condition. There are limited studies related to anaerobic condition and (to our knowledge) no study on the removal of EDCs in landfill leachate by AnMBR. Moreover, for most studies under anaerobic condition, the removal of EDCs was only reported in the liquid phase; solid phase extraction was not reported, thereby preventing mass balance in the studies. This research was conducted to investigate the potential of AnMBR for reduction of organic strength and removal of EDCs in landfill leachate. A novel lab-scale upflow anaerobic sludge blanket (UASB) reactor equipped with dual-flat sheet ultrafiltration and microfiltration membrane modules was designed and constructed to test the potential to remove EDCs and traditional landfill leachate constituents (COD, turbidity). The target EDC was 17β-estradiol (E2), a prevalent female hormone used for contraceptives and hormone replacement therapy. Due to the nature of packaging and widespread use in households, the entry of E2 into landfills is highly likely, and has been reported. The quantification of E2 from liquid phase in this project is performed by the use of solid-phase microextraction (SPME) with GC/MS. Batch assays were conducted to determine the anaerobic biodegradability of E2 as well as to measure the respective distribution coefficients of E2 to PAC, colloids and anaerobic sludge biomass. In the adsorption batch assays, it was found that the PAC has stronger adsorption potential than anaerobic sludge. The adsorption potential of E2, E1 and EE2 on sludge follows the order E2>EE2>E1 which correlates to the Kow values (4.01, 3.67, 3.1, respectively). However, all three compounds showed the same adsorption potential to the Norit 20B PAC. The biodegradability of E2 was investigated in both liquid and solid phase and under several conditions such as methanogenesis, methanogenesis with aid from PAC, and methanogenesis with additional alternative electron acceptors added (sulfate and nitrate). E2 was found to transform to E1 under all tested conditions. The compounds are present in both liquid and solid phase. E2 and E1 were not detected (< 4ng/L and <10ng/L, respectively) in the liquid phase after 25 days in most cases except the case of adding additional sulfate. The AnMBR was designed, fabricated and operated for 2 years. During the stable condition period of the AnMBR, the high removal efficiencies of COD and E2 achieved were around 92% and 98%, respectively. However, E2 was still detected in the effluent at average concentrations of 30-40 µg/L range. To expand hormone retention and removal by the AnMBR, as well as to control membrane fouling, powder activated carbon (PAC) was added to the reactor. After the PAC was added, the concentration of E2 was reduced to less than the detection limit (4ng/L) in both MF and UF effluents. The log removal of E2 in the AnMBR system increased immediately from 1.7 without PAC to 5.2 after PAC was added. This study demonstrated that the AnMBR has high potential for removal of E2, and with aid from PAC, the AnMBR can remove E2 from landfill leachate to levels below detection limit.
54

An integrated environmental risk assessment for marine protected areas in Hong Kong with special reference to the ecological impacts of endocrine disrupting chemicals

Xu, Genbo, 徐亘博 January 2014 (has links)
abstract / Biological Sciences / Doctoral / Doctor of Philosophy
55

Biotransformation potential of phytosterols in biological treatment systems under various redox conditions

Giles, Hamilton 21 May 2012 (has links)
Phytosterols are naturally occurring compounds which regulate membrane fluidity and serve as hormone precursors in plants. They also have the potential to cause endocrine disturbances in aquatic animals at concentrations as low as 10 µg/L. Wastewaters from several industries which process plant matter can contain phytosterols at concentrations in excess of the above-stated level. Despite their endocrine disruption potential, very little is known about phytosterol physical properties and their biotransformation potential in biological treatment systems. Aerated stabilization basins (ASBs) are common biological treatment systems in North American pulp and paper mills. ASBs are large open lagoons which use tapered surface aeration to remove COD and prevent sulfate reduction in the water column. Phytosterols are released from wood during the pulping process and a small fraction enters the wastewater stream during washing of the pulp. Therefore, phytosterols may be exposed to aerobic or anaerobic environments depending on their solubility and solid-liquid partitioning behavior. The overall objective of this research was to systematically and quantitatively assess the biotransformation potential of phytosterols in biological treatment systems and to examine conditions leading to reduction of these compounds in wastewater effluent streams. The results of this research showed that phytosterols are sparingly soluble with aqueous solubility below 1 µg/L when present as a mixture. Phytosterols have a strong affinity to adsorb to solids and dissolved organic matter. The affinity for aerobic biomass was greater than for wastewater solids. The stigmasterol desorption rate and extent from wastewater solids increased with an increase in pH from 5 or 7 to 9. Phytosterols were biotransformed under aerobic conditions but not under sulfate-reducing or methanogenic conditions by stock cultures developed in this study. Biotransformation under nitrate-reducing conditions could not be confirmed conclusively. The continuous-flow system was successful in removing 72 to 96% of phytosterols. Biotransformation accounted for 23, 14 and 41 % of campesterol, stigmasterol and β-sitosterol removal, respectively. Phytosterols accumulated in the reactor sediment and accounted for 97 % of the total phytosterols remaining in the system. Phytosterols can be removed from wastewater streams during biological treatment by a combination of biotransformation and solids partitioning and control of system pH, DO and available carbon and energy sources can increase the degree of phytosterols removal. The results of this research can be used to engineer effective biological treatment systems for the removal of phytosterols from pulp mill wastewaters and other phytosterol-bearing wastewater streams.
56

Characterization and Modeling of Selected Antiandrogens and Pharmaceuticals in Highly Impacted Reaches of Grand River Watershed in Southern Ontario

Arlos, Maricor Jane January 2013 (has links)
Endocrine disruption and high occurrences of intersex have been observed in wild fish associated with wastewater treatment plant (WWTP) effluents in the urbanized reaches of the Grand River watershed located in southern Ontario, Canada. WWTP effluent is a complex matrix with diverse aquatic environmental contaminants and stressors. This study aimed to: (1) characterize the spatio-temporal distribution and fate of antiandrogenic personal care products (triclosan, chlorophene, and dichlorophene), along with selected pharmaceuticals (carbamazepine, ibuprofen, naproxen, and venlafaxine) and the herbicide, atrazine in the Grand River watershed and (2) model the behaviour of these contaminants in the aquatic environment. Water sampling of 29 sites which covered six municipal WWTPs and ~100 km of river length was completed during summer low flows (July 2012). Monthly samples were also collected immediately upstream and downstream of a major WWTP (Kitchener) from August to November 2012. Many of the target pharmaceuticals and triclosan were detected in WWTP effluents in the Grand River watershed, especially those that did not nitrify (minimal treatment with high ammonia). Chlorophene was either undetected or was only found at trace levels in the effluents. Under low flow conditions, triclosan and several other pharmaceuticals exhibited a spatial pattern where concentrations increased directly downstream of the WWTPs, then decreased with distance downstream (dilution and/or degradation). Chlorophene, in contrast, was not found downstream of most of the WWTP outfalls but was first detected at a site 5 km upstream of a WWTP and then continued with relatively constant concentrations for approximately 29 km downstream. It was also only found during the summer sampling period. Atrazine was consistently found in all sampling locations which reflected the agricultural non-point source nature of this compound. The WASP 7.5 model (US Environmental Protection Agency) was adapted and calibrated to a reach of the Grand River associated with the Kitchener WWTP. The simulation of the fate and transport of the target compounds revealed that flow-driven transport processes (advection and dispersion) greatly influence their behaviour in the aquatic environment. However, fate mechanisms such as biodegradation and photolysis also potentially play an important role in the attenuation of most compounds. The exception was carbamazepine where it was shown to act as a conservative tracer compound for wastewater specific contaminants in the water phase. The fate model developed can be applied in the future to predict the fate of a wide variety of contaminants of emerging concern across the watershed to help define the exposure of these biologically active chemicals to sensitive ecosystems.
57

The Fate of Net Estrogenicity and Anti-Estrogenicity During Conventional and Advanced Biosolids Treatment Processes

Citulski, Joel 19 January 2012 (has links)
Biosolids are the nutrient-rich organic residual materials resulting from the treatment of domestic sewage at a wastewater treatment facility, and are increasingly land-applied for agricultural and land-reclamation purposes as part of the wastewater management process. While the presence and fate of estrogenic endocrine-disruptors (eEDCs) in wastewater has been extensively studied, much less focus has been given to examining the presence and fate of eEDCs during biosolids treatment. In particular, little work has been done to measure the net estrogenic potency of biosolids using in vitro bioassays, such as the Yeast Estrogen Screen (YES) assay. This is despite the fact that widespread land-application of biosolids provides for the direct introduction of eEDCs into terrestrial and aquatic environments. The relative scarcity of bioassay-based net estrogenicity data for sludges and biosolids is in large part due to the analytical challenges involved in working with such a complex sample matrix. Comprehensive sampling at wastewater treatment plants in Guelph and London, ON, demonstrated that the estrogenicity of anaerobically-treated biosolids is considerably lower (12.0-19.7 ng/g estradiol-equivalents) than that reported in earlier published studies. The results of the present study were made possible due to the development of a sample preparation methodology that overcame the toxic effects that sludge and biosolid samples typically exert on yeast cells in the YES assay. An anti-estrogenicity assay was also applied for the first time to sludges/biosolids to measure the extent to which antagonistic compounds ‘block’ the response of the YES assay. The results of these tests suggest that although the net estrogenicity of anaerobically treated solids is indeed low, up to twice the amount of estrogenicity measured by the YES assay may be masked in biosolids by the presence of antagonistic compounds. While aerobic treatment conditions reduced net estrogenicity to at-or-below detectable levels, net estrogenicity remained relatively constant throughout the unit processes of the anaerobic treatment train. Biosolid ageing during storage led to an overall decrease in net estrogenicity of both conventionally-treated “restricted use” and advanced-treated “unrestricted use” anaerobic biosolids. However, levels of net estrogenicity were observed to spike during the early stages of storage, particularly under freeze/thaw conditions. / Natural Science and Engineering Research Council of Canada (NSERC) PGS-D3 scholarship, Water Environment Association of Ontario, Canadian Water Network
58

Assessment of the sensitivity of North American fish species to endocrine disrupting chemicals in vitro

2015 January 1900 (has links)
There is concern regarding exposure of aquatic organisms to chemicals that interfere with the endocrine system. Disruption of the endocrine system can lead to impacts on sexual development, altered hormone levels, intersex, and ultimately reproductive failure. While effects of endocrine disrupting chemicals (EDCs) on standard laboratory species have been subject of intense study, to this day there is a large gap in knowledge and a high degree of uncertainty regarding the sensitivity of wild fish species to these compounds. One of the main concerns with current toxicity testing approaches is that they require the use of a large number of live animals, particularly when working with native species. Therefore, the aim of this study was to develop in vitro tissue explant assays that would enable the assessment of the sensitivity of different wild fish species native to North America to the exposure with EDCs. Specifically, two in vitro assays were developed: 1) A liver explant assay to assess effects of EDCs that can interact with the estrogen receptor (environmental estrogens), and 2) a gonadal explant assay to assess effects of EDCs on sex-steroid production. The test species selected were northern pike (Esox lucius), walleye (Sander vitreus), and white sucker (Catostomus commersoni) that were sampled from Lake Diefenbaker, Saskatchewan, Canada, and white sturgeon (Acipenser transmontanus) that were randomly selected from an in house stock reared from eggs. Liver tissue was excised from male fishes and exposed for 24 h to a synthetic estrogen, 17α- ethinylestradiol (EE2). Transcript abundance of vitellogenin (VTG), estrogen receptor (ER) α and β in liver tissue were quantified using qPCR. Gonad tissue from both male and female were excised and exposed for 24 h to a model inducer (forskolin) and inhibitor (prochloraz) of steroidogenesis. 11-ketotestosterone (11-KT) and estradiol (E2) were quantified in media by use of ELISA. Exposure to EE2 resulted in a concentration dependent increase in VTG in all species, and an increase in ERα in northern pike. Walleye males showed the greatest sensitivity to EE2. Gonad tissues exposed to forskolin showed a concentration dependent increase in 11-KT and E2. Exposure to prochloraz resulted in a decrease of 11-KTand E2. Male and female white sucker showed greatest sensitivity to forskolin, while male and female walleye showed greatest sensitivity to prochloraz. The seasonal time point during which gonad explants were excised and exposed had an impact on the potency and magnitude of response, resulting in a seasonal effect on sensitivity. Also, gonad explants from these species were found to have greater sensitivity than responses previously reported for in vitro explants of other fish species such as the fathead minnow (Pimephales promelas), and stable cell lines currently used as screening applications to detect chemicals that might disrupt the endocrine system. Therefore, current approaches that use stable cell lines or tissue explants from standardized small bodied laboratory species might not be protective of some wild fish species. These tissue explants represent a promising approach to help understand species sensitivity to EDCs, and if appropriately validated, could be a powerful tool for chemical screening.
59

Physiological, morphological, and behavioural effects of developmental exposure to Aroclor 1254 in nestling and juvenile songbirds

2014 December 1900 (has links)
Over the past several decades, there has been growing concern among the public and scientific community regarding adverse health effects resulting from exposure to natural and synthetic compounds that act as endocrine disrupters. The structural similarity of many of these compounds to natural hormones and receptors, as well as their ubiquity in the environment, can result in the potential for interference with the endocrine system of wildlife and humans. Much of the research examining the adverse effects of wildlife exposure to endocrine disrupting chemicals (EDCs) has focused on effects on reproduction or short-term changes in hormone physiology. However, organisms exposed to low levels of EDCs at early life stages could also be susceptible to developmental effects, including neurological and other physiological changes affecting later life stages. In birds, migration can be an important component of the annual life cycle and it can be vulnerable to disruption given that it is under endogenous hormonal and neurological control. Previous studies have shown that developmental exposure of birds to thyroid hormone disruptors, such as polychlorinated biphenyls (PCBs), have resulted in reduced hatching success, lower growth rates, teratogenicity, impaired development, and immunotoxicity. In this thesis, I aimed to supplement what is currently known regarding the effects of developmental exposure to low levels of a mixture of endocrine disrupting chemicals in songbirds, as well as further investigate the latent consequences of such an exposure on migratory life stages. I initially investigated the potential physiological and developmental effects of early exposure to Aroclor 1254, a PCB mixture, in two passerine songbird species: European starlings (Sturnus vulgaris) and red-winged blackbirds (Agelaius phoeniceus) during the critical nestling period. In 2011, European starlings and red-winged blackbirds were orally administered Aroclor 1254 over the period of nestling development, which was repeated in 2012 with only European starlings. For both years, morphological parameters (body mass, tarsus, wing-chord and bill-lengths) were measured daily and plasma thyroid hormones were measured. Additional measurements of wing chord and tarsus length fluctuating asymmetry (FA) were taken in the second year, to further assess contaminant-induced alterations in developmental stability. I found that treatment with environmentally-relevant levels of Aroclor 1254 caused increasing liver residues above the controls but did not result in overt effects on morphological growth parameters during the nestling period in either starlings or red-winged blackbirds. However, we did observe significant differences in 2012 starling’s wing chord FA at day 10 and 13, and tarsus length FA between all treatment groups and controls, indicating the potential for PCB-induced stress. Nestling thyroid hormone profiles (T3) sampled throughout the nestling period supported developmental changes but did not reveal any differences among treatment groups. Starlings were subsequently reared in captivity and further tested during a simulated autumn migration. Migratory activity and orientation were tested using Emlen funnel trials over 6 consecutive weeks. Across treatment groups, we found a significant increase in mass, fat, and feather moult, and decreasing plasma thyroid hormones over time. At 12L:12D, control birds showed a peak in activity and a directional preference for 155.95° (South-southeast), while high-dosed birds did not. High-dosed birds showed a delayed directional preference for 197.48° (South-southwest) under 10L:14D, concomitant with apparent delays in moult. These findings link alterations in avian migratory behaviour to contaminant-specific mechanisms. Exposure to a ubiquitous environmental endocrine disruptor exerted only subtle short-term effects during the period of exposure but importantly, latent effects may be far more relevant for individual fitness. We discuss how the impacts of exposure during early stages of development were not significant for short-term nest success, but can still give rise to longer time-scale effects that are potentially relevant for survival and population stability for migratory birds.
60

Application of toxicogenomic approaches to study chemical-induced effects on the hypothalamic-pituitary-gonadal (HPG) axis of the Japanese medaka (Oryzias latipes)

Zhang, Xiaowei. January 2008 (has links)
Thesis (Ph. D.)--Michigan State University. Dept. of Zoology & Environmental Toxicology, 2008. / Title from PDF t.p. (viewed on Mar. 30, 2009) Includes bibliographical references. Also issued in print.

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