Theses and Dissertations from UMD
Permanent URI for this communityhttp://hdl.handle.net/1903/2
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item Occurrence of Pharmaceuticals and Personal Care Products (PPCP) & Artificial Sweeteners (AS) in Surface Waters of Maryland's Chesapeake Bay Western Shore(2022) Gibbs, Alexandra Marie; Filoso, Solange; Gonsior, Michael; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In the United States, nutrient, personal care products (PPCP) and artificial sweeteners (AS) pollution in lakes, rivers, and estuaries is a problem that has been recognized for decades and is of special concern for many in coastal Maryland. PPCP are used on a daily basis, and include prescription analgesics, antibiotics, over-the-counter medications, fragrances, and cleansers. AS are synthetic sugar substitutes, ubiquitous in everyday food and drink, including soft drinks, baked food and dairy products. The widespread use of PPCP and AS by human populations results in their sustained contribution to surface waters via wastewater treatment. This study used 13 PPCP and 2 AS to describe their sources and temporospatial patterns in Maryland’s Western Shore. Sampling was conducted over three seasons in 2021 at 79 sites, including headwater streams, groundwater, and rivers feeding into the Chesapeake Bay. Sites were influenced by a mix of wastewater treatment plants (WWTP) and onsite wastewater treatment systems (OWTS). The detection frequency of the study compounds ranged from 2% to 100% in large catchments and 31% to 100% in headwater catchments. Six PPCP and AS were measurable at 80% or more of the sites, illustrating their ubiquitous presence throughout the study area. During the study, individual PPCP and AS concentrations were highly variable temporally, ranging from non-detectable to 6.58 μg/L. Major factors controlling concentrations were proximity to wastewater treatment, discharge and season. Four compounds—Ace-K, carbamazepine, sucralose and caffeine—were used as tracers to identify wastewater sources as they have distinct removal efficiencies during wastewater treatment and have anthropogenic origins. Caffeine to sucralose/Ace-K/carbamazepine ratios were used to identify discharges of untreated wastewater. Finally, PPCP and AS concentrations were explored in one headwater stream during storm events. Stormflow discharge was shown to impact the water quality of the receiving waters. The combination of discharge data, OWTS distribution data, an extensive suite of PPCP and AS and varied catchment types used in this thesis contributes to the understanding of human sourced wastewater pollution in coastal communities.Item ASSESSING THE IMPACTS OF NON-POINT SOURCE FRESHWATER AND NUTRIENT INPUTS ON A SHALLOW COASTAL ESTUARY(2019) Butler, Thomas; Hood, Raleigh R; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Academic research models for Chesapeake Bay have, traditionally, been forced with USGS inputs, flows and nutrient loads from 10 major rivers. These tributaries fail to account for 100% of the inputs entering the Bay. In contrast, models used for determining Total Maximum Daily Load for Chesapeake Bay are forced with output from a watershed model at thousands of locations, presumably, accounting for all these inputs. Our aim is to increase understanding of the impacts different forcing schemes have on water quality model simulation. Simulations were completed using three forcing approaches: 1) using “traditional” USGS-derived input from 10 major rivers; 2) using “concentrated” input from 10 major rivers derived from watershed model output; and 3) using “diffuse” input from 1117 rivers derived from watershed model output. Comparisons of these schemes revealed large impacts on simulations in Chesapeake Bay during periods of high flow and extreme weather events under diffuse forcing.Item A CASE STUDY OF URBAN STUDENT AND TEACHER EXPERIENCES SURROUNDING AN OUTDOOR ENVIRONMENTAL SCIENCE FIELD TRIP(2009) Preusch, Peggy Louise; van Zee, Emily H; Curriculum and Instruction; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Field trips provide opportunities for students to experience many different contexts beyond the classroom, and are a popular choice of K-12 teachers in the US. Recent interest in learning that occurs at informal science education centers such as museums, zoos and aquariums has stimulated studies of the relationship between learning in and outside of schools. Although many studies focus on the teachers, the contexts, and/or the students during the field trip, only a few look at the entire process of learning by including the classroom setting before and after the field trip. This study was designed to develop understandings of the student process of learning during and surrounding an environmental science field trip to an outdoor setting. John Dewey's extensive writings on the relationship between experience and learning informed the analysis, creating a focus on active and passive elements of the experience, continuity within and across contexts, the interactive nature of the experience and the importance of subject matter. An exploration of environmental education (EE), environmental science (ES), and nature study as content revealed the complexities of the subject matter of the field trip that make its presentation problematic. An urban school was chosen to contribute to the research literature about urban student learning in outdoor environments. During the field trip, the students' active engagement with each other and the environment supported meaningful remembrances of the field trip experiences during interviews after the field trip. The students accurately described plants and animals they had observed in different habitats during the field trip. They also made connections with their home life and prior experiences in the outdoors as they discussed the field trip and drew pictures that represented their experiences. One student integrated his outdoor experience with a language arts assignment as he reflected deeply on the field trip. One implication of this study is that educational experiences in outdoor natural environments are complex in ways that contribute to lack of continuity between science lessons in an elementary classroom and environmental science field trip. Long term relationships between schools and informal settings that recognize the strengths of both contexts in terms of student learning processes surrounding field trip experiences are needed to strengthen the educative process for field trip participants.