<p> Environmental service-learning is an intentional educational experience(s) wherein learners engage in meaningful activities designed to serve the environment. Environmental service-learning activities vary according to their learning and service goals and include ecomanagement, persuasion, legal action, economic action and political action. The purpose of this mixed methods research was to explore the ecological and educational impacts of grades 6-12 environmental education, with special attention to environmental service-learning throughout Portland, Oregon.</p><p> Ecological impacts considered restoration and conservation outcomes of several environmental service-learning programs including plant communities, soils, litter removal and trail maintenance. Educational outcomes considered aspects of environmental literacy including locus of control, environmental sensitivity, indicated environmentally responsible behaviors, investigating environmental issues and knowledge of physical systems. The relative influence of some significant life experiences on youths' response to environmental education, including environmental service-learning, was also considered. Telephone surveys were used to gather data from 22 Portland metropolitan area environmental education programs. Data included 2014 annual biophysical impacts (e.g., area of invasive species removed, pounds of litter removed) and information on programming (e.g., length of program, % time outside). Eleven programs administered a 33-question environmental literacy assessment to participants of their programs (n=393). The assessment included the New Environmental Paradigm, the Inclusion of Nature in Self, questions from Environmental Identity Scale and self-constructed questions. One 8^th grade program was identified for a detailed case study. In this 8^th grade programs, slight variations in educational activities occurred among three treatment groups which varied the amount of time youth spent engaged in ecomanagement. Youth from the three treatment groups and a control group were administered the environmental literacy assessment at the beginning and end of the program. Qualitative data for the youth in the treatment groups were gathered to further consider how environmental literacy was impacted by participation in the program. </p><p> Stronger associational correlations to environmental literacy occurred for the percentage of time an environmental education program spent outdoors rather than the percentage of time an environmental education program engaged in environmental service-learning (e.g., &ldquo;With other people, I can work to make a positive impact on the environment.&rdquo; rho: .276 vs. &ldquo;I have the skills necessary to make a positive impact on the environment.&rdquo; rho: .176). Random forests indicated that environmental education program features and some significant life experiences could predict collapsed environmental literacy variables (locus of control, environmental sensitivity and environmentally responsible behaviors). 22.4% of the variance in a collapsed environmental sensitivity variable was explained by nine predictor variables; those variables with the strongest influence were youth response to &ldquo;Before this program, how frequently did you spend time in the outdoors&rdquo;, age and the presence of a positive adult role model who cares for the environment. Youth participating in environmental education programs showed higher environmental literacy than control groups (e.g., &ldquo;I feel an important part of my life would be missing if I couldn't get out and enjoy nature from time to time&rdquo; U: 3642.500, p: 0.025). Youth with significant formative life experiences (e.g., those indicating previous environmental education or a positive adult role model that cares for the environment) responded better (higher environmental literacy) to environmental education than those youth without (&ldquo;I pay special attention to things outdoors.&rdquo; chi 10.633, p: 0.031).</p><p> This research provides insight on the efficacy of environmental service-learning. Environmental service-learning positively affected environmental literacy, but outdoor environmental education was more effective in terms of environmental literacy. Results corroborate the body of literature regarding significant life experiences. Further, results suggest that significant life experiences are a critical development milestone necessary for youth to respond to environmental education on a developmental trajectory to empowered environmentally literate citizens.</p>

The human health significance of waterborne viruses has previously relied on epidemiological data from documented waterborne outbreaks. It is difficult, however, to assess the risks involved to individuals and communities from exposure to low levels of contamination. Risk assessment is a useful tool in the interpretation of water quality data and can be used to better understand the significance of exposure to low-level contamination of viruses in water. Microbial risk assessment was applied to determine the risks associated with environmental exposure to waterborne coxsackievirus and adenovirus. Annual risks of infection for drinking water were determined to be as high as 10⁻¹ for both coxsackievirus and adenovirus at exposure levels of 0.13 PFU/l and 0.001 IU/l, respectively. A comprehensive cost-of-illness analysis was conducted for three waterborne viruses--Norwalk virus, rotavirus, and non-polio enterovirus--to determine the economic impact of waterborne viruses in the United States. Annual medical costs and productivity losses were estimated in 1993 dollars using actual outbreak information and data from epidemiological studies. It was estimated that $1.1 to $6.9 billion is spent each year in the United States due to these viral illnesses, with potentially $0.39 to $2.4 billion attributable to water. The United States Environmental Protection Agency (USEPA) has initiated the Information Collection Rule (ICR) in which water utilities serving >100,000 people will be required to collect data on the concentrations of specific microorganisms in source and finished water beginning in 1997. Selected water utilities will be required to archive water samples for possible further viral analyses. A risk assessment approach was undertaken to determine which virus would be appropriate for the analyses of the archived water samples. The following viruses were selected based on the nature of the different diseases associated with each, their occurrence in waterborne outbreaks, and their resistance to inactivation by disinfectants: rotavirus, coxsackievirus, hepatitis A virus, adenovirus, Norwalk and Norwalk-like viruses, astrovirus, and hepatitis E virus. The polymerase chain reaction (PCR) is the recommended detection method. The results of these analyses will provide both a database on the occurrence of these viruses in water as well as their susceptibility to water treatment.

Contaminants in aquatic systems tend to associate with particles and colloidal material and their impact on the environment is dependent on the nature and behavior of these carrier particles. This study investigates the role of aggregation and sedimentation in the fate and transport of particles and aggregates. Computational fluid dynamics modeling illustrates the significance of the hydrodynamics of porous aggregates on aggregation. Aggregation numerical modeling incorporating the porous fractal nature of aggregates results in accurate representations of particle size distribution evolutions compared to laboratory experiments. Settling velocities of aggregates that show non-Stoke's like behavior can be modeled taking into consideration the drag coefficient correction and the fractal porous density of the flocs. Applying the new aggregation and sedimentation model to a resuspension event suggests that the risk of exposure to contaminants in the water column is minimal as a consequence of washout and larger settling velocities of porous fractal aggregates.

<p> This thesis seeks to understand the impacts and outcomes of a six-week wildlife habitat monitoring internship on the 12 adolescent students who participated. The opportunity for this project sprung from my involvement in the design and implementation of this internship at Walking Mountains Science Center in Avon, Colorado. The interns spent six-weeks performing field data collection for the United States Forest Service, learning about ecology, botany, and environmental ethics, and earning college credit for their work. Inductive analysis was used to analyze data from a variety of sources. The results indicated that this internship was an effective model for instilling a sense of place, commitment to conservation, and increased sense of self-efficacy among its participants. Hands-on field research of this type has potential to increase sense of place, commitment to conservation, and a sense of self-efficacy, thereby augmenting a student's engagement in science, and improving performance in advanced science courses.</p>

Aquifer flow-through columns were operated for 12 weeks to evaluate the benefits of oxygen addition on the biodegradation of a Chlroboenzene (CB) DNAPL source zone. Quantitative PCR was used to measure total bacteria (16S rDNA) and several aromatic oxygenase genes. CB removal was faster in the oxygen-amended columns compared to a control column, and qPCR showed that whereas the biphenyl and toluene dioxygenase biomarkers were most abundant, increases in the biomarker concentration for the phenol hydroxylase gene reflected best the higher CB removal due to aerobic biostimulation. DGGE analyses of the soil amended with oxygen revealed the dominant presence of Rhodococcus erythropolis (89% sequence similarity), which belongs to a genus known for its ability to degrade many priority pollutants, including CBs.

Arsenic has become a major contaminant of concern due to the increased knowledge of its toxicological and carcinogenic effects on human health, causing the maximum contaminant level (MCL) to be lowered from 50mug/L to 10mug/L in the United States. Lowering the MCL requires improving current methods or developing new ones to remove arsenic from the drinking water. Currently, there are many methods to remove arsenic, such as coagulation iron salts, ion exchange, and membranes. These methods can be expensive, have poor removal efficiency, and produce a large amount of waste. In this research, magnetite nanoparticles are evaluated as arsenic sorbents due to there magnetic properties for removal, minimal production of waste, and high surface area. Also, in this work, the kinetics of adsorption was examined along with the competitive adsorption of other ions (chloride, phosphate, sulfate, silica, and bicarbonate) in solution. Equilibrium was reached in about two hours for arsenate and arsenite; however, approximately 90% of the arsenate and arsenite was adsorbed within thirty minutes with 0.5g/L Fe3O4. The arsenate and arsenite equilibrium concentrations are similar which demonstrates the affinity of magnetite nanoparticles for both arsenite and arsenate. This work presents a model which predicts the amount of arsenic adsorbed by magnetite nanoparticles in the presence of several ions using a modified rate equation. To test the viability this arsenic removal method, it was tested on spiked arsenic tap water and arsenic contaminated groundwater from Brownsville, TX. In each case, the treatment goal of less than 10mug/L was reached with minimum residual iron in the water. Therefore, these results suggest that using magnetite nanoparticles is a feasible process to remove arsenic from the drinking water. This process could be applied as a household treatment system for developing and developed countries.

A mathematical module was developed to evaluate the effect of the common fuel additive, ethanol, on benzene fate and transport in groundwater, and to discern the most influential benzene plume-elongating mechanisms. The module, developed for the RT3D (Reactive Transport in 3-Dimensions) model, includes previously evaluated fate and transport processes (advection, dispersion, adsorption, biodegradation and depletion of molecular oxygen during ethanol degradation) and substrate interactions (dilution of benzene metabolic flux, catabolite repression and microbial populations shifts) previously not considered. Benzene plume elongation predictions, based on literature model parameters, were on the order of 22%-40% for a constant source of E10 gasoline (10% v/v ethanol), which compares favorably to field observations (56%, Ruiz-Aguilar et al., 2003). Oxygen depletion during ethanol degradation was the principal mechanism hindering benzene natural attenuation, followed by metabolic flux dilution. When oxygen is not limiting, model simulations showed that microbial growth on ethanol could offset negative substrate interactions and enhance benzene degradation, resulting in shorter plumes.

A previously developed model describing colloidal fouling of membrane filters (Sethi, 1997) predicts that operation under conditions of constant transmembrane pressure should result in less fouling than operation at constant permeate flux. These predictions were tested in a series of laboratory experiments. The influence of particle size and mode of operation on the specific permeate flux performance of a cross-flow flat slit membrane unit, was evaluated using an ultra-filtration membrane mounted in an existing Osmonics SEPA CF membrane module. Experiments of three hours in duration were conducted with polystyrene latex particles (100 nm, 430 nm, and 1000 nm) which resulted in a strong correlation between particle size and specific permeate flux. Consistent with theoretical prediction, less fouling was observed in a constant pressure mode of operation. However difference in between the two modes of operation with different particle sizes were not as great as anticipated. Indications for a strong influence of the flowing layer on the specific permeate flux performance were found for the 1000 nm particles. Future research for a better understanding of the role of the flowing layer and cake resistance in membrane fouling is needed and recommended.

An experiment was designed to test the hypothesis that bioremediation within DNAPL source zones is feasible provided all limiting factors are delivered in adequate amounts. A demonstration-scale aboveground aquifer simulation system was bioaugmented with a mixed anaerobic dechlorinating culture after the addition of neat PCE below the water table. Hydrogen Releasing Compound RTM was introduced to the tank to provide a long-term and steady supply of reducing equivalents for dechlorination. The system effluent was monitored for chlorinated ethene concentrations, and results demonstrated the dechlorination of PCE to trichloroethene (TCE) and cis-dichloroethene (cis-DCE). Measurements at the end of the study indicated the following mole fractions in the effluent: cis-DCE (66%), TCE (24%), and PCE (10%).

Organic matter is one of the major components of the fine particles in Houston. In the present study, fine particulate samples collected at three sites (plus one temporary site) in Houston have been investigated to determine the molecular composition and seasonal variation patterns of individual organic compounds, including n-alkanes, PAH compounds, petroleum biomarkers, alkanoic and alkenoic acids, dicarboxylic acids and levoglucosan. Next, chemical mass balance (CMB) model has been applied to calculate quantitative contributions from major primary emission sources to ambient PM2.5 levels. These emission sources include diesel engine trucks, gasoline powered vehicles, wood combustion, paved road dust, food preparation process, vegetative detritus and natural gas combustion. Source profiles suitable for the present CMB model have been developed based on source test results published in literature and our road dust resuspension experiment. Source apportionment shows diesel and gasoline vehicle exhaust to be the major primary contributors to ambient PM2.5 collected in Houston. Moreover, 52% of annual average PM2.5 mass measured in the present study can be attributed to secondary formation in the atmosphere.