Two municipal landfills and one public septic system in Southern Ontario were studied as potential sources of the pharmaceuticals ibuprofen, carbamazepine, gemfibrozil, caffeine, sulfamethoxazole, and naproxen to groundwater. The background chemistry at each site was also determined. Pharmaceutical analysis was conducted using isotope dilution techniques, coupled with solid phase extraction followed by high performance liquid chromatography electrospray tandem mass spectrometry (HPLC-ESI- MS/MS). An assessment of method performance and extensive quality assurance and quality control practices were employed. At the septic system site, pharmaceuticals were detected at the furthest sampling point, 30 m downgradient from the source area. The highest concentrations measured in groundwater were for carbamazepine (2,050 ng L-1), sulfamethoxazole (1,990 ng L-1) and ibuprofen (1,790 ng L-1). The other pharmaceuticals analysed were observed at concentrations in the range of <1 to 10 ng L-1 (gemfibrozil), <8 to 625 ng L-1 (naproxen), and <1 to 160 ng L-1 (caffeine). Under saturated groundwater transport, attenuation was not strong within the plume as all pharmaceuticals were detected at distance from the source. In the unsaturated zone, most pharmaceuticals appeared to be more greatly attenuated than in the saturated zone. This greater extent of removal in the unsaturated zone is attributed to increased degradation associated with elevated oxygen concentrations. At the two landfill sites, no pharmaceutical compounds were detected in any of the groundwater samples collected within previously defined plumes. Assuming these drugs are disposed in landfill wastes, the absence of detections suggests degradation and attenuation of these pharmaceuticals is occurring. Some of the conditions that may contribute to attenuation include a thick unsaturated zone, strongly reducing conditions, and high sorptive capacity of the waste. Specifically, waste typically has a higher organic content than aquifer materials, and a lower pH, particularly in the early stages of decomposition. These conditions would result in a potentially higher attenuation of drugs within the waste pile. This study suggests that management programs focused on protection of groundwater quality should take into consideration the potential persistence of pharmaceuticals in septic system environments.

Packer tests in boreholes in fractured rock involving injection or withdrawal of water in borehole segments have been standard practice in bedrock hydraulic investigations pertaining to geotechnical and water resource projects since the 1950’s. However in contaminant hydrogeology, the tests are conducted to assess groundwater velocity and contaminant fluxes and therefore, much improved resolution and measurement accuracy is needed. For this thesis study packer testing equipment was designed specifically for studies of contaminant behavior in fractured rock with the ability to conduct four types of hydraulic tests: constant head/flow injection step tests, slug tests, pumping tests and recovery tests, all in the same borehole test interval without removing the equipment from the hole while acquiring high precision data for calculation of transmissivity (T) and fracture hydraulic apertures (2b). This equipment records pressure above, within, and below the test interval to gain insights regarding open borehole flow patterns, and to identify short circuiting to the open borehole above or below the test interval. The equipment measures flow rates as low as 6 ml/min up to 20 L/min, and the temperature in the test interval and at the ground surface is measured to account for density and viscosity variations. Each type of test is conducted repeatedly over a wide range of imposed applied pressures and flow rates and the equipment was applied to assess performance of this new methodology for packer testing and gain new insights concerning fractured rock hydrology in 6 boreholes in the fractured dolostone aquifer underlying the City of Guelph, Ontario. In the first stage of the equipment application in the fractured dolostone aquifer, over 150 high precision straddle packer tests using constant rate injection (Q) were conducted to identify the conditions of change from Darcian (linear) to non-Darcian (non-linear) flow based on the Q vs dP relationship where dP is the applied pressure above ambient. In the Darcian regime, the linear Q vs dP relationship passes through the origin (0,0) where the ambient pressure represents static conditions (i.e. Q=0 and dP=0). After the onset of non-Darcian flow, proportionally less Q per unit dP occurs so that the interval transmissivity (T) calculated from the test results using Darcy’s Law based models is underestimated by as much as an order of magnitude. The Darcy-Missbach equation was found to be a robust conceptual model for representation of step constant Q tests in which the linear proportionality constant relates Qn vs dP. It was found that quantifying non-linear flow allows for a more accurate determination of the linear data to obtain better estimates of T and hence the hydraulic apertures derived from the T using the Cubic Law. In order to obtain hydraulic apertures from the packer test T values, the number of hydraulically active fractures in the test interval is needed. The only data collected regarding individual fractures was the core log created during the coring process and the acoustic televiewer log, both of which identify the location of fractures, but neither could tell if the fractures identified were hydraulically active. A sensitivity analysis concerning the effects of non-linear flow and the number of hydraulically active fractures on the calculated hydraulic aperture shows that the number of fractures selected as hydraulically active has the greatest effect on the aperture values. A new approach is proposed for determining apertures from hydraulic tests in fractured rock utilizing the onset of non-linear flow to aid in the choice of the number of active fractures present in the test interval. In the second stage of the equipment application, the four types of hydraulic tests (constant head, pumping, recovery, and rising/falling head slug tests) conducted in the same test interval at gradually increasing flow rates showed that non-linear flow can be most easily identified and quantified using constant head tests providing a higher degree of certainty that the data used to calculate T are from the Darcian flow regime. Slug tests are conducted most rapidly, but formation non-linear behavior is commonly exaggerated by non-linearity within the test equipment at large initial displacements. However, the equipment non-linearity can be accounted for using a Reynolds number (Re) analysis allowing identification of the non-linear flow in the formation. In addition, non-linear flow can interfere with evidence of fracture dilation. The pumping and recovery tests are the most time consuming because of the relatively long time required to reach steady state. However, these tests offer the most potential to give insight into the influences of the peripheral fracture network and rock matrix permeability on test results In addition to the actual transmissivity of the test interval T values obtained from packer tests can be influenced by several factors including non-linear flow in the formation and in the test equipment, aperture dilation or closure, hydraulic short circuiting or leakage from the test interval to the open borehole and dual permeability properties of the system (fractures and matrix). The equipment and procedures developed in this thesis provide an improved framework for identifying these influences and in some cases avoiding them so that the aperture values calculated from T measurements are more accurate than those obtained through conventional approaches. In the conventional procedures for packer testing in fractured rock as recommended in manuals and guidance documents, the applied head and flow rate can be expected, based on the results of this thesis, to produce transmissivity values biased low because of non-linear (non-Darcian) flow.

The importance of the hydroxyl radical (OH) to tropospheric chemistry is well known. The radicals’ ability to react with most atmospheric trace gases allows it to act as the main removal mechanism for these gases. Due to the highly reactive nature of OH, the oxidizing capacity of the atmosphere is often defined simply by its concentration. Owing to its significant role, knowledge of all OH chemistry, homogeneous and heterogeneous, is important to understanding the chemistry of the troposphere. In order to accurately predict future levels of OH and other trace gases, a thorough understanding of all processes and variables involved in the emission and sequestering of these compounds is essential. The gas-phase chemistry of OH is well known and has been extensively characterized. The one process that scientists are still trying to fully understand is its involvement in heterogeneous chemistry. Some studies have suggested that the inclusion of OH heterogeneous chemistry is important to fully model tropospheric chemistry, while other studies have suggested that it can be neglected entirely. It is therefore important to study and understand the conditions in which heterogeneous chemistry is significant. In order to do this accurately, scientists must first understand the process and magnitude of the uptake of OH onto atmospherically relevant surfaces. The main objective of this work was the development of a new analytical tool for the study of heterogeneous hydroxyl radical reactions. To this end, experiments were conducted to determine the most efficient approach to couple a low pressure aerosol flow tube (LP-AFT) to a chemical ionisation mass spectrometer (CIMS). The use of CIMS allowed for the accurate detection and quantification of hydroxyl radicals. Through iterative experimentation the system was designed and became operational. Experimental work focused on laboratory studies of reaction kinetics, with data reported in this work representing the reactions of OH with model atmospheric aerosols. The uptake of OH on organic aerosols was examined using the newly developed LP-AFT-CIMS system at standard temperature. Liquid oleic acid particles were used to mimic atmospherically relevant particles. The uptake coefficient, γ, on oleic acid particles was determined to be 0.49 ± 0.08 for a log-normally distributed aerosol at ~400nm. This value is in very good agreement with currently published data. However, the overall error of this method (~16%) is observed to be lower than other currently available methods, which have errors ranging from 20 – 30%. It is postulated that the mass accommodation coefficient, α, for OH radicals on organic surfaces approaches this value under standard atmospheric conditions. It’s also suggested that under the correct conditions the heterogeneous loss of OH could contribute to the overall budget of the OH radical. Further atmospheric implications of this reaction are discussed.

The current study monitored DO, stable isotopes of O2 (δ18O-O2 and δ18O-H2O) along with water quality parameters on both a diel and day-time only basis in the Grand River over several seasons and locations. A dynamic dual mass-balance model was developed to quantify rates of community respiration (CR), gross primary production (GPP), and gas exchange coefficients (k) in the Grand River, Ontario, Canada. Monitoring was conducted at three locations along a longitudinal gradient: 1) West Montrose, located upstream of the cities of Kitchener and Waterloo in a predominately agricultural landscape; 2) Bridgeport, located downstream from WM and the Conestogo tributary confluence, and 3) Blair, located downstream of the cities of Kitchener and Waterloo. Values of k in the Grand River ranged from 3.6 to 8.6 day-1, over discharges ranging from 5.6 to 22.4 m3 s-1. The k values were relatively constant over the range of discharge conditions studied. Overall, k values obtained with the isotope model for the Grand River were found to be lower than predicted by the traditional approaches evaluated, highlighting the importance of determining site-specific values of k. Metabolism results indicated that the Grand River is negatively impacted by both agricultural and urban inputs from the surrounding catchment. Metabolism rates in the Grand River (GPP = 2.2 to 19.9 and CR = 4.0 to 29.6 g O2 m-2 d-1) were found to be greater than published estimates for relatively undisturbed systems. In particular, net production at Blair was consistently below zero, indicating that DO inputs are not sufficient to overcome the oxidative demand upstream of this location. The addition of an isotopic mass balance provides for a corroboration of the input parameter estimates between the two balances, and constrains the range of potential input values to allow for a better estimate of GPP, CR and k. Input parameter uncertainty and sensitivity most likely reflect the dynamic processes occurring in the Grand River watershed. A better understanding of processes affecting δ18O-O2 would improve the capability of the model to replicate observed data, and provide more confidence in predicting metabolic processes in impacted rivers.

Dissolved organic matter (DOM) is a heterogeneous mixture of organic compounds comprised mostly of carbon, oxygen, nitrogen, and hydrogen, but is often operationally defined as the concentration of dissolved organic carbon that passes through a 0.45 μm filter. Derived from the degradation of both plant and animal organic matter, DOM can act as an important redox constituent within groundwater, or form carcinogenic disinfection-by-products during water treatment. It is important to understand the quality of DOM in order to be able to understand how it will react within its environment. A number of different techniques are used to characterize DOM (such as resin fractionation, ultraviolet and visible light absorption, and fluorescence) but these techniques can be both laborious and time consuming, in addition to requiring large amounts of sample. Recently, a new technique has been developed, Liquid Chromatography – Organic Carbon Detection (LC-OCD), that provides a fast and reproducible technique. LC-OCD can group components of DOM into six categories based upon molecular weight: hydrophobics (HPho), humic substances (HS), building blocks (BB), low molecular weight neutrals (LMW-N), and acids (LMW-A). Furthermore, the molecular weight and aromaticity of HS can be determined. The primary goal of this thesis was to use the LC-OCD to better understand characteristics of DOM, with special attention to how the quality of DOM can be defined.

Dissolved organic matter (DOM) is a heterogeneous mixture of organic compounds comprised mostly of carbon, oxygen, nitrogen, and hydrogen, but is often operationally defined as the concentration of dissolved organic carbon that passes through a 0.45 μm filter. Derived from the degradation of both plant and animal organic matter, DOM can act as an important redox constituent within groundwater, or form carcinogenic disinfection-by-products during water treatment. It is important to understand the quality of DOM in order to be able to understand how it will react within its environment. A number of different techniques are used to characterize DOM (such as resin fractionation, ultraviolet and visible light absorption, and fluorescence) but these techniques can be both laborious and time consuming, in addition to requiring large amounts of sample. Recently, a new technique has been developed, Liquid Chromatography – Organic Carbon Detection (LC-OCD), that provides a fast and reproducible technique. LC-OCD can group components of DOM into six categories based upon molecular weight: hydrophobics (HPho), humic substances (HS), building blocks (BB), low molecular weight neutrals (LMW-N), and acids (LMW-A). Furthermore, the molecular weight and aromaticity of HS can be determined. The primary goal of this thesis was to use the LC-OCD to better understand characteristics of DOM, with special attention to how the quality of DOM can be defined.

Thesis (M.S.) in Teaching--University of Maine, 2007. / Includes vita. Includes bibliographical references (leaves 68-70).

Thesis (M.S.) in Education--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 43-48).

Thesis (M.S.) -- University of Texas at Dallas, 2006 / Includes vita. Includes bibliographical references (leaves 24-25)

Thesis (Ph.D.) -- University of Texas at Dallas, 2005 / Includes vita. Includes bibliographical references (leaves 155-169)