Triclosan (TCS) as an antimicrobial agent in a variety of consumer products has drawn environmental and health care scientist's attention for over 40 years as it has been widely detected in environment. Once released to the environment, TCS can easily transfer to water bodies and soil due to its fair solubility and hydrophobicity. TCS is not considered as a toxic compound. However, two main reasons have bolded TCS occurrence important in the environment. Firstly, TCS can easily adsorb to and accumulate in the media possessing organic matter such as sludge, soli or tissue. Secondly, TCS can degrade/transform to other compounds with higher potential toxicity and persistency. While many degradation products have been observed in certain circumstances, the main easily-formed products can be pointed as 2,4-dichlorophenol (2,4-DCP), 2,8-dichlorodibenzoparadioxin (2,8-DCDD) and methyl triclosan (MTCS). 2,4-DCP is listed as the priority toxic pollutant by US Environmental Protection Agency. 2,8-DCDD is a member of dioxin family with a recently reported relative potency factor of 1₉104. This compound is suspected to transform to higher chlorinated dioxins when exposed to light or chlorine. MTCS, resulted from microbial methylation of TCS, has received much attention recently due to its persistency. Although TCS has been studied vastly, its̀ fate and behavior in wastewater and sludge as the first receiver in the environment has not been investigated deeply so far. In this research, attempt was done to answer some so far unanswered questions such as whether i) TCS occurrence is consistent within a single STP and between different STPs, ii) TCS transformation is a factor of wastewater and sludge treatment, iii) TCS degradation occurs in aerobic/anaerobic sludge digestion, iv) TCS adsorption is predictable and obeys any equilibrium and kinetics model. Two gas chromatography-mass spectrometry (GC-MS) based-methods were successfully developed for determination of TCS, 2,4-DCP, 2,8-DCDD and MTCS in wastewater and sludge. In the first method, liquid-liquid extraction (LLE) and silica column chromatography were applied for the extraction and cleanup of wastewater. In the second method, accelerated solvent extraction (ASE) and multilayer silica column chromatography were employed for the extraction and cleanup of sludge. For validation purpose, the methods were successfully applied to wastewater and sludge samples from three different municipal sewage treatment plants (STPs) in Hong Kong. Satisfactory mean recoveries for all target compounds were obtained as over 82% and 84% for wastewater and sludge samples, respectively. TCS degradation products were detected based on the treatment practice. 2,8-DCDD was detected in the plant utilizing UV disinfection at the mean level of 20.3(±4.8) ng.L-1. 2,4-DCP was identified in chemically enhanced primary treatment (CEPT) applying chlorine disinfection at the mean level of 64.5(±4.5) ng.L-1. Besides, MTCS was detected in the wastewater collected after biological treatment 33.3(±3.4) ng.L-1 as well as in sludge samples that have undergone aerobic digestion at the mean level of 266.1 (±14.2) ng.g-1 dry weight (d.w.). Mass balance of TCS in three STPs and the extent of TCS transformation to the degradation compounds were investigated and adsorption behavior of some of the occurred compounds was studied. Moreover, TCS fate was probed in full scale plant during wastewater and sludge aerobic/anaerobic treatment condition. Finally few correlations were investigated. For STP (I), 77.6% of the entering TCS mass flux to the plant was directly discharged to the receiving environment. The mass that was settled along the sludge underwent aerobic digestion treatment of which 52.2% was aerobically degraded in the digester. However 5.4% of the TCS in the sludge was observed to be transformed to MTCS and 47.8% was remained in the dewatered sludge to be disposed to landfill. TCS elimination in STP (II) wastewater treatment was 25.5%. Chlorination could cause 5.3% of TCS loss during disinfection process. Nevertheless, still 68.7% of the loading TCS was discharged to the environment through wastewater. TCS mass flux in pretreatment and post treatment sludge was almost constant. For STP (III), 14.2% and 8% of initial TCS mass flux was adsorbed to primary and secondary sludge, respectively. Mass balance between TCS lost in the biological treatment, the mass adsorbed to the sludge and the effluent revealed that 44.0% of the initial TCS mass flux was biodegraded in biological treatment of which 19.8% was transformed to MTCS. In addition, 10.3% of TCS mass was lost in UV irradiation disinfection unit of which 90.8% was transformed to 2,8-DCDD. Significant TCS mass loss (20.6%) was observed in anaerobic digestion of sludge and the remaining mass in dewatered sludge was disposed to landfill. No other degradation product was observed in the dewatered sludge except MTCS that showed insignificant change in mass flux after anaerobic digestion. Kd values were calculated for TCS, MTCS and 2,4-DCP for the first time based on the concentration of target compound in liquid and solid phase. Moreover, temporal-based variation of TCS and its degradation products were statistically proved. A relationship was attributed between TCS fraction adsorbed to the particulates in raw wastewater and elimination efficiency in primary treatment (r = 0.83, 0.66 and 0.87 for STP (I), (II) and (III), respectively). Adsorption behavior of TCS, 2,4-DCP and MTCS to primary and secondary sludge was investigated. For this purpose, a simple and efficient GC-MS-based method was developed for simultaneous determination of TCS, MTCS and 2,4-DCP in wastewater. Batch experiments were carried out and effect of various parameters such as pH, temperature and sludge concentration were studied. Three isotherm models, Linear, Freundlich and Langmuir were examined to fit the adsorption data. Amongst, Linear and Freundlich isotherm models were able to describe the system behavior well while Langmuir isotherm model did not exhibit satisfactory result. Relevant Kd values were derived for three compounds and were compared to the full scale. Pseudo-first and second order kinetics models were applied to describe the kinetic data. Pseudo-second order kinetic was found to fit well over the range of applied initial concentrations based on the regression coefficients and the relative error for the calculated equilibrium sorption capacity which implied the sorption of TCS, MTCS and 2,4-DCP onto the inactivated dried sludge proceeds predominantly through a pseudo-second order kinetics.

Please read the abstract in the section front of this document / Dissertation (M Eng (Chemical Engineering))--University of Pretoria, 2007. / Chemical Engineering / unrestricted

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This thesis examines how the secondary effects of environmental regulations are assessed before the regulations are proclaimed. Negative secondary effects of a policy (such as regulation) may outweigh direct benefits; it is important that secondary effects are clearly assessed. The case study is the control of organochlorines in the Canadian pulp and paper industry via federal regulation of dioxins and furans and British Columbia's regulation of Adsorbable Organic Halogen (AOX). The thesis is founded upon the premise that sustainability must be an integral consideration. A systems approach is used to evaluate assessments and to generate recommendations. The evaluation is divided into two parts: the process of assessing the regulation and the contents of the assessments. Background information is provided on organochlorines, pulp and paper making, the pulp and paper industry and the relevant regulatory processes. A chronology of the regulation is established. Assessments are reviewed from five classes of stakeholders: industry, labour, environmentalists, the federal government and the British Columbia government. The study found that secondary impacts of the regulation were less important than the primary action, which was managing the risk posed by organochlorines in effluent. For the secondary assessments, stakeholders felt problems with the process were greater than shortcomings in content. In particular, governments' lack of response to submissions caused a lack of confidence in the system, which was well-founded in British Columbia's highly political process. The federal Regulatory Impact Analysis Statements gave a valuable but limited summary of impact assessments and the rationale behind the regulations. To improve the process of creating environmental regulation I recommend that the federal government assemble a reference document for assessments, that all levels of government institute class assessments for general cases, and that all stakeholders use a consistent, multiobjective framework. The proposed framework is presented. / Graduate and Postdoctoral Studies / Graduate

The purpose of this dissertation is to provide a better economic basis for the discussion on how much natural capital the current generation should be allowed to deplete. Chapter I uses overlapping-generations models to show the effects of different assumptions about which generation owns the stock of a natural resource on the distribution of intergenerational welfare. An increase in the share of the resource stock that is owned by the first generation, reduces welfare of later generations. If the first generation owns the full resource stock, intermediate generations have to be sufficiently wealthy to buy the resource from the first generation and sell it to later generations. This channelling effect can lead to a situation of resource abundance followed by rapidly increasing resource prices and scarcity. Chapter II show that the incompleteness of intergenerational insurance markets constitutes a market failure that leads to inefficient intergenerational investment decisions. Risks that increase from generation to generation would be under-insured by the current generation. Examples of excessive reduction of biodiversity, excessive natural resource depletion, and inefficiently low protection against global warming are provided. Chapter III analyzes the decision theoretical foundation of environmental choices under uncertainty. Since ambiguity and ignorance are important aspects of many environmental problems, subjective expected utility theory (SEU) has significant limitations as a normative decision making model. The use of SEU leads to a systematic bias against the conservation of natural capital. An alternative decision model is suggested based on the Dempster-Shafer belief-function theory and Choquet expected utility. The synthesis in chapter IV suggests that the costs of natural capital depletion are systematically underestimated in conventional analysis. To remedy the biases against future generations and the complete valuation of natural capital, a sustainability constraint on the economic activities of the current generation is proposed. This constraint requires compensation for natural capital depletion through functional substitutes. From this sustainability constraint, an operational sustainable supply rule is derived for determining shadow prices of natural capital depletion. / Business, Sauder School of / Graduate

Near the earth's surface, ozone is a highly toxic and reactive pollutant. In order to avoid potentially hazardous concentrations near densely populated areas, accurate forecasts of the temporal variability of ozone are necessary. Several statistical models which may be used to understand the temporal variability of ozone as well as to forecast short-term ozone fluctuations are developed. The models may be divided into two distinct categories: (1) those which forecast daily maximum one-hour average ozone concentrations and (2) those which forecast the diurnal behavior of one-hour average ozone concentrations. To assess the relative utility of each model, their forecast ability is evaluated by statistical comparison with data not used in model development. Most of the developed models appear to perform reasonably well; however, the utility of any forecast model is dependent upon the needs of the user. It is believed that the limits of the "pure time series" method (i.e., mathematical decomposition of time series into various elements) have been approached. Future investigations with these data should attempt to answer specific questions regarding the physical mechanisms governing ozone variability. / Arts, Faculty of / Geography, Department of / Graduate

The issue of tensions between market access and environmental protection is relatively new focus in the domain of international trade. This article suggests solutions to this conflict within the WTO framework so that while pursuing the goals of free trade and promoting development of economy the objective of 'sustainable development' can be achieved at the same time. This article includes an introduction, the main body (three chapters) and conclusion. j The Introduction starts by describing the development of the regimes of market access and environmental protection; it goes on to analyze the causes of the tension between the two and finally emphasizes the importance of resolving this tension within the World Trade Organization (WTO) framework. Chapter One elaborates on the existing principles, regulations and exception in the WTO framework and states that these regulations cannot live up to expectations of the developed countries and environmentalists. The conclusion is that it is impractical for the developing countries to avoid this issue. Chapter Two starts with an inquiry into the crux of tensions between free trade and environmental protection. It goes on to enlist different proposals by academic scholars and compare these principles' application in European Community Treaty (EC) and North American Free Trade Agreement (NAFTA), hoping to resolve the tensions between market access and environmental protection. Chapter Three summarizes academic proposals and experiences of EC and NAFTA and discusses possible practical resolutions within WTO including both short-term measures and long-term ones. This chapter concludes by suggesting possible courses of action for China that could allow it to sustain the 'green challenge.' The Conclusion discusses the objectivity and unavoidability of the tensions between the free trade and the environment protection and reinforces the importance of resolving the problem within the WTO framework as well as the necessity of amending related regulations and harmonizing environmental standards of the WTO members. / Law, Peter A. Allard School of / Graduate

This dissertation consists of three chapters discussing the effects of changing trade barriers for Canadian firms and a final chapter investigating hazardous waste trade, one of the important environmental issues in international business. The first three chapters use simple theoretical structures and firm level data to examine the evolution of Canadian manufacturing following the tariff changes imposed by the Canada-US Free Trade Agreement. Chapter one considers the influence of falling tariffs on firm survival, chapter two investigates how trade liberalization effects firm growth in terms of size and productivity, and the third chapter considers the implication o f falling trade barriers for firm financial structure. The fourth chapter diverges from the first three to explore the determinants of international shipments in hazardous waste using a gravity model with factor endowment conditions and waste trade data from 89 countries. / Business, Sauder School of / Graduate

The effects of short term exposures to sublethal doses of mercuric chloride were studied using species of anadromous fish. Aspects of grou/th and behaviour u/ere used as indicators of physiological and psychological malfunctions due to mercurialism. The characteristic migration tendencies ( upstream or downstream ) of Lower Babine and Fulton River alevins were tested in experimental laboratory channels. The were conducted in a chamber in which a day, dawn through dusk, could be simulated. Each stock was divided into three groups and each group was assigned a level of treatment ( control, 0.5 ppm and 1.0 ppm HgCl₂ ). The performance of the fish in each group placed in the channels was scored. An analysis of data obtained from the migration experiments indicated that sublethal mercurialism had a disruptive influence on migration patterns of Sockeye salmon alevins. The lower level of intoxication produced a downstream drift in both stocks while the fish treated at the higher level of intoxication showed an upstream migrational tendency in both stocks. The effects of sublethal mercurialism on growth were studied using Sockeye, Chum, and Coho salmon fry. The fish received standard daily feedings. The fed fish for each of the species were divided into three treatment groups ( control, 0.5 ppm and 1.0 ppm mercuric chloride ) .Weight data were collected and analyzed using regression analysis and the analysis of covariance. The fed Sockeye and Chum salmon fry showed a significant weight loss (⍺= 0.05 ) in the 0.5 ppm and the 1.0 ppm treatments when compared to their respective controls. There was no significant difference in weight between treatments in the fed Coho salmon experiment. A six week starvation experiment was designed to test if there were any significant differences in weight loss between control fish and fish treated with 0.5 ppm and 1.0 ppm mercuric chloride. Regression analysis and the analysis of covariance did not reveal any statistically significant differences on the rates of weight loss. A flight responce experiment was conducted using Coho salmon prey and predators. Wild and hatchery Coho salmon prey were used with hatchery Coho predators. Three treatment levels of mercuric chloride were administered ( control, 0.5 ppm and 1.0 ppm ), Prey and predators were placed in an experimental laboratory performance channel and, after a timed exposure to each other, scores indicative of flight responce mere obtained. The data was analyzed using the Kolmogorov-Smirnov Large sample : one tailed test. No significant differences in the responces between treatments were noted for the hatchery Coho. The wild Coho prey treated with 0.5 ppm and 1.0 ppm mercuric chloride had a statistically significant differences when compared to their controls. It was noted that as the level of intoxication increased the the level of flight responce decreased. The results of the above experiments indicate that mercurialism has measurable effects on the physiology and psychology of fish at sublethal level. / Science, Faculty of / Zoology, Department of / Graduate

The Fraser Estuary was investigated five times under varying flow regimes. The surface distribution of dissolved manganese consistently exhibited a maximum value at a salinity ranging from 4 to 12 ppt. Experimental results and field data suggest this peak does not result from the desorption nor dissolution of riverborne suspended particulate manganese. The excess metal is derived from the estuarine bottom sediments. Desorption or dissolution of manganese from the estuarine bottom sediments resuspended due to the advancing salt wedge enhances the dissolved manganese concentration in the bottom waters, especially in the toe of the salt wedge. This manganese enrichment may also be influenced to a lesser extent by the concurrent release of some interstitial water with enriched dissolved manganese concentrations due to the in situ reduction of amorphous manganese oxides. The subsequent entrainment and mixing of water from the toe of the salt wedge into the outflowing river water causes a downstream increase in the dissolved manganese content, and eventually determines the peak manganese concentration and salinity. Further downstream mixing with saline waters having relatively low manganese levels causes surface concentrations to decrease. Thus, the dissolved manganese distribution can be explained in terms of two conservative dilution curves which intersect at the manganese peak. The dissolved oxygen generally behaves conservatively in both the surface and bottom waters of the Fraser Estuary. The removal of alkalinity may occur at low salinity, however, alkalinity exhibits conservative behaviour through most of the salinity range. The surface distribution of pH can be replicated theoretically only when mixing in the surface is considered as a two step process. The alkalinity behaves conservatively in the surface waters of the Strait of Georgia. The pH and dissolved oxygen display seasonal variations related to primary productivity and mixing processes. The distribution of dissolved manganese in surface waters of the Strait of Georgia is determined mainly by the dilution of Fraser River water. Bottom waters have enhanced dissolved manganese concentrations due to reductive remobi1ization of manganese from the sediments. Concentrations of dissolved manganese at mid-depths are determined by seasonal variations in the stability of the water column. Depth profiles of suspended particulate manganese indicate increasing concentrations with depth. This may result from the oxidative precipitation of manganese and/or the resuspension of bottom sediments. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate