Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 149-178) Also available in print.

Thesis (M.Eng.). / Written for the Dept. of Chemical Engineering. Title from title page of PDF (viewed 2009/06/17). Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 149-178) Also available online.

Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Apr. 16, 2010). Includes bibliographical references.

To date, limited research has been conducted on the effects of cytotoxic drugs on aquatic species. Three of these species, a single celled plant, an invertebrate and a fish, were exposed to six cytotoxic drugs, both singly and as simple mixtures. A range of endpoints were assessed, including growth inhibition in algae, immobilisation in daphnia and the impact on organ size and the expression of the DNA damage repair genes RAD51 and p53 in zebrafish. No effects at environmentally relevant concentrations were observed in any of the three species.

Each and every one of us is exposed to chemicals on a daily basis and contributes to the global issue of chemical pollution. Humankind has become heavily dependent on the use of man-made chemicals in order to sustain the increased quality of life that is generally seen globally. There is however a price to pay in that we generally live in a world that is polluted by anthropogenic chemicals. From the water we drink to the food we eat there will be some trace of chemical residues; you just need to look closely enough and/or know what you’re looking for. With many hundreds of thousands of man-made chemicals approved within Europe for use in various ways, it is no surprise that we come into daily contact with them. What is also important to understand is that the presence of a man-made chemical is not enough to establish whether it poses a risk to environmental or human health; it needs to be present in sufficient amounts to elicit an effect. Over the past 20 years the focus of my research been on understanding which chemicals we should be concerned with, which pose the greatest risk and why do they pose such a risk. This work is of major societal and scientific significance as it protects the world we live in whilst teaching us about the better regulation of the chemicals we have become so dependent. To understand the nature of my research it is important to understand that prior to the mid-nineteen nineties hazardous organic chemicals were typically restricted to lists comprising of a number of banned (and typically chlorinated) pesticides, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans and the antifouling biocide tributyltin (TBT). One of the major enigmas that faced environmental scientists at the time was that even though it was possible to quantify and monitor the presence of the above hazardous substances in the environment, they often didn´t explain the environmental quality measured though biological effects on organisms. Chemicals are globally regulated on an individual substance level and subsequently within the context of influencing these regulations, for the improved protection of environmental and human health, it is therefore essential to know which chemical contaminants are actually causing biological effects. It is also necessary to know the levels at which any organism will be exposed and what the consequences of these levels. My research subsequently became focused on two separate approaches; identifying which substances actually cause the biological effects unexplained by hazardous substances and evaluating the occurrence, environmental fate and ecotoxicity of those chemicals not routinely monitored or present on priority lists of hazardous substances; a group of chemical contaminants later termed contaminants of emerging concern (CECs). An effect-directed non-target approach A targeted approach to environmental analysis infers that we know exactly what we should be looking for. Whilst this is a suitable approach for chemicals that we suspect may be of concern, it does not help us understand which other contaminants may be present in the environment and potentially causing harm. When embryos of oysters exposed to estuarine surface waters developed deformities and this could not be attributable to the levels of priority hazardous substances a bioassay-directed non-target approach to environmental analysis was developed to identify chlorinated and alkylphenols as responsible [5, 6]. This approach has subsequently evolved into the approach termed effect-directed analysis (EDA) and is widely used globally for the identification of CECs. My own research has successfully applied the approach to identify for the first time a number of important environmental contaminants; steroidal androgens [10, 13, 14] as environmental contaminants, the phthalate ester bis(2-ethylhexyl)phthalate [10], cinnarizine, cholesta-4,6.dien-3-one [19], C1-C5 and C9 alkylphenols [21], petrogenic naphthenic acids [57] as environmental estrogen receptor agonists, C1-C5 and C9 alkylphenols [21], PAHs and petrogenic naphthenic acids [57] as androgen receptor antagonists and unresolved polar aromatic compounds as important environmental genotoxins [15]. Another focus of my effects-directed research has been identifying environmental contaminants that exert the same effects as dibenzo-p-dioxins and polychlorinated dibenzofurans in that they are aryl hydrocarbon receptor (AhR) agonists. Dioxin-like chemicals are ubiquitous in the environment and in addition to those that are routinely monitored there are a large number of other compounds that exert dioxin-like effects [26, 28, 32, 33, 37, 52, 64, 82, 93, 98, 99]. Better understanding of AhR agonists will in the long run help protect the environment and humans from a particularly hazardous group of chemicals. A targeted approach The early- to mid-nineteen nineties saw the widespread introduction of liquid chromatography coupled to mass spectrometry (LC-MS) to the environmental analytical toolbox. Robust instruments typically using electrospray and atmospheric pressure chemical ionisation were well suited to the analysis of the more polar CECs, such as alternative antifouling biocides to TBT, pharmaceuticals, personal care products, veterinary medicines, illicit drugs and rodenticides. Robust analytical methodology is key to my research [2, 4, 18, 31, 34, 35, 42, 49, 66, 69, 72, 73, 86, 94, 102] as it allows the better understanding of how contaminants behave and interact with the environment. Development of robust, specific and sensitive methods for the analysis of alternative antifouling biocides [2, 4] allowed for the first time an evaluation of their life-cycle from release at the paint surface, and the factors that influence this [3], their occurrence in the environment [7, 8, 12, 29], fate and behaviour [12, 16] and subsequent effects [36, 41]. Assessment of the environmental risks based upon these data showed that both Irgarol 1051 and diuron were a threat to freshwater and marine algae. The significance of this research is that it subsequently led to restrictions being placed on the use of Irgarol 1051 and diuron in antifouling products in a number of European countries [58] and an awareness of the hazards associated with the deliberate release of biocidal products into the environment [86]. Observations of human pharmaceutical residues in the chromatograms of wastewater effluent samples being analysed by EDA and reports of their occurrence in German wastewaters motivated the development of LC- tandem MS methods for the quantification of pharmaceutical residues in waste- and surface waters [18]. Pharmaceuticals, we showed, occur in treated wastewater effluents and marine and freshwater recipients [24, 25, 30, 42, 43, 51, 66] and that, to no great surprise, the per capita pharmaceutical loads from hospitals were greater than the general population [43, 51]. Other highlights include understanding the processes that occur within sewer systems and what influences pharmaceutical occurrence in the final treated effluent [59, 60, 81, 85, 105], all of which allow for a better assessment of the overall risk posed to the environment. Even though several hundred papers have been published on pharmaceuticals in the environment since my early work, this has almost exclusively been focused on the parent pharmaceutical ingredient in aqueous matrices from developed counties. To remedy this shortfall more recent work has focused on quantifying the proportion of pharmaceutical metabolites released as compared to the parent [66], pharmaceutical occurrence in sludges and sediments [69], as well as evaluating occurrence in less studied water cycles [101].

Contaminants of emerging concern (CECs) are an unregulated suite of constituents frequently detected in environmental waters, which possess the potential to cause a host of reproductive and developmental problems in humans and wildlife. Degradation pathways of several CECs are well-characterized in idealized laboratory settings, but CEC fate and transport in complex field settings is poorly understood. In the present study I use a multi-tracer solute injection to study and quantify physical transport and photodegradation in a wastewater effluent-impacted stream in Ankeny, Iowa. Conservative tracers are used to quantify physical transport processes in the stream. Use of reactive fluorescent tracers allows for isolation of the relative contribution of photodegradation within the system. Field data were used to calibrate a one-dimensional transport model, and forward modeling was then used to predict the transport of sulfamethoxazole, an antibiotic in the effluent which is susceptible to photolysis. Results show that accurate predictions of reactive CECs at the scale of stream reaches can be made using the fate and transport model based on field tracer studies. Results of this study demonstrate a framework that can be used to couple field tracer and laboratory CEC studies to accurately predict the transport and fate of CECs in streams.

The presence of pollutants known as emerging contaminants in water and wastewater is a topic of growing interest. Emerging contaminants, which include endocrine disrupting chemicals (EDCs) and pharmaceutical and personal care products (PPCPs), are compounds that remain relatively unknown, although their adverse effects have been proven. Emerging contaminants are not satisfactorily removed by traditional treatment methods; therefore, there is a need for innovative techniques. Advanced oxidation processes (AOPs) have been recognized as successful removal methods for these problematic pollutants. However, technical success is not the only factor that must be considered. Process engineering, environmental, and economic and social parameters were considered. A holistic analysis was completed using a ranking system to determine the performance of several AOPs (ozonation, UV, photocatalysis, the Fenton reaction, and integrated processes). Ultimately, H2O2/O3 presented the highest average ranking (3.45), with the other processes showing similar performance, with the exception of TiO2 photocatalysis (2.11).

There are many reports indicating the presence of emerging contaminants such as: estrogen hormones, 1,4-dioxane and perfluoro-octanoic acids in the natural environment. Estrogen hormones are considered important emerging class of contaminants due to their endocrine disrupting effects. These compounds are invariably found in the environment originating mostly from natural sources. Trace concentrations of estrogen hormones (low µg/L concentrations) have been detected in municipal wastewater treatment plants and observed in receiving water bodies. 1,4-Dioxane (C4H8O2) is used as an organic solvent and solvent stabilizer numerous in chemical processes. The United States Environmental Protection Agency (US-EPA) has recognized 1,4-dioxane as a toxic chemical and a possible human carcinogen. 1,4-dioxane has been detected as a contaminant in the natural environment, drinking water supplies, superfund sites, public groundwater sources in the United States, Canada and Japan at concentrations greater than the permissible standards. Perfluorinated chemicals such as perfluoro-octanoic acid (PFOA) and perfluorooctane-sulfonate (PFOS) have been manufactured for use in a variety of industrial and consumer applications. Due to their environmental persistence, PFOAs have been detected in surface waters at a number of locations at concentrations ranging from pg/L to ng/L. Elevated concentrations of PFOAs have been measured in surface and ground waters near specific point sources. Through this project, successful attempts have been made for the destruction of emerging contaminants using ultrasound. This study deals with the optimization of various process parameters for the destruction of estrogen hormones. The influence of process parameters such as power density, reactor geometry, power intensity, ultrasound amplitude, and external mixing was investigated. Artificial neural network (ANN) approach was used to describe the interactions between optimized parameters. The important findings obtained in the present work for the optimized estrogen degradation can help tackle the challenges of scale up such as operational optimization and energy consumption. The effect of process conditions such as pH and presence of oxidizing agents on the ultrasonic destruction of 1,4-dioxane and PFOA was studied. Acidic conditions favored the destruction of both the compounds. The presence of activated sulfate radicals enhanced the reaction rate kinetics. An innovative technology using electric potential and ultrasound for the removal organic contaminants was developed. The existence of organic contaminants in ionic form under certain process conditions has led to the development of this technology. Applying a low electric potential across the probe enhances the mass transfer of the contaminants into effective reaction zone, thereby enhancing the total destruction. A two-fold increase in the reaction rates was observed. This study shows ultrasound as an efficient and effective treatment technology for the destruction of emerging contaminants. / Civil Engineering

There are many reports indicating the presence of various emerging contaminants (ECs) in treated wastewater and other water sources. The detection of such contaminants in the environment and the ability of these contaminants to pose potential threats to the environment at very low concentrations have led to a need for more efficient treatment technologies. Cyclodextrins (CDs) have gained significant interest as an alternative adsorbent for water and wastewater treatment because of their unique physico-chemical characteristics and excellent selectivity towards organic compounds. The property of CD to form inclusion complexes with various molecules through host-guest interactions has made it a useful compound for the removal of a number of contaminants from water and wastewater. The overall goal of the study is to identify and develop a novel adsorbent for the removal of ECs of interest. The specific objectives are a) to synthesize various beta-cyclodextrin (BCD) based adsorbents by coating BCD onto different supports such as silica, filter paper, iron oxide, and zeolite, b) to perform batch and column experiments using the developed adsorbents, c) to evaluate the performance of the adsorbents in different water matrices such as MQ water, simulated wastewater in presence of humic acid, and real municipal wastewater, d) to study the regeneration potential of the adsorbents. In this research, various (BCD) based hybrid adsorbents were synthesized and their performances were evaluated based on the removal of selected ECs. At first, chemically bonded BCD onto silica particles as hybrid adsorbents were synthesized by using crosslinking agents and copolymers. Three different methods were used to synthesize 14 different BCD coated silica adsorbents. The adsorbent prepared by reacting BCD with hexamethylene diisocyanate (HMDI) as crosslinking agent and dimethyl sulfoxide (DMSO) as solvent showed best results in removing the ECs studied. The adsorbent showed more than 95% removal of 17β-estradiol (in single component) and more than 90% of most of the estrogens (mixture of 12), more than 99% of perfluorooctanoic acid (PFOA) (in single component) and more than 90% of most of the PFCs (mixture of 10), and a maximum of 90% removal in case of BPA. The adsorption capacity of the developed adsorbent was observed to be higher for the removal of 17β-estradiol and PFOA than that of commercially available activated carbon (F400) in MQ water. In order to represent the real environmental scenario, further batch experiments were conducted for the removal of two PFCs (PFOA and PFOS (perfluorooctane sulfonic acid)), 17β-estradiol, and BPA at environmentally relevant concentrations from wastewater. The adsorbent was effective in removing the ECs that were spiked in the secondary effluent of a municipal wastewater treatment plant. Furthermore, the adsorbent was successfully regenerated with methanol over four cycles without significant loss in its adsorption capacity for the removal of PFOA and estrogens. Ozonation as an alternative method of regeneration was also used and the process was also very effective in regenerating the adsorbent over seven successive cycles for the removal of BPA and 17β-estradiol. The characterization of the adsorbents using FTIR, TGA, and TEM confirmed the coating of BCD onto silica particles. The TGA results showed high thermal stability of the adsorbent (upto 300oC). As an alternative to chemical impregnation, another method of synthesis was developed where various BCD based hybrid adsorbents were synthesized by physically impregnating hydroxypropyl BCD (hpBCD) polymer onto three different supports: iron oxides, zeolite, and filter paper. The hpBCD impregnated filter papers were synthesized by solvent evaporation method and different adsorbents were synthesized by varying the polymer loadings. The polymer loading was optimized based on the performance of the modified (polymer impregnated) filter paper in terms of its filtration capacity as well as adsorption capacity to remove PFOA and BPA. The magnetic adsorbent was prepared by mixing hpBCD polymer with iron oxide (Fe3O4) particles. It was observed that by increasing the mixing time of the support (Fe3O4) with the polymer from 48 to 96 hr, the adsorption capacity of the adsorbent (hpBCD polymer coated Fe3O4) could be significantly enhanced. The same approach was also used to synthesize hpBCD polymer coated zeolite adsorbent and both adsorbents (hpBCD/zeolite and hpBCD/Fe3O4) were effective in removing the selected ECs from MQ water, simulated water, and wastewater. / Civil Engineering