Biology Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2749
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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.