Master of Science (MS), Ohio University, 2024, Geological Sciences

Dense non-aqueous phase liquids (DNAPLs) are a group of volatile organic compounds (VOCs) that are commonly used industrially and frequently escape confinement and reach the water table. DNAPLs are denser than water and thus sink until reaching a confining layer, at which point weak solubility leads to the formation of a dilute dissolved contaminant plume as groundwater flows by which can then pollute and threaten downstream wells and water supplies. Existing remediation methods for DNAPL plumes are generally unsatisfactory and not very effective while also requiring significant investment in time and labor. This study continues work on the slow-release permanganate gel (SRP-G) first proposed by Lee et al. (2013) and further developed by Gupta (2013), Hastings (2021), and Acheampong (2023) in a flow-tank setting and examines its effectiveness in remediating a dilute dissolved plume of trichloroethylene (TCE), a common DNAPL contaminant. A 200 ppb TCE solution was pumped through the flow tank and SRP-G was injected. MnO4 - release and spread was monitored in twelve wells at three depths and samples were collected from three locations for TCE analysis. A statistically significant negative correlation was found between MnO4 - in solution and TCE concentration. This demonstrates that the SRP-G was able to effectively remediate the TCE contaminant plume and reduce contaminant concentration to approximately half of background levels. Future studies are suggested examining SRP-G behavior and remediation potential in anisotropic heterogeneous media and in field settings.

Master of Science in Engineering, Youngstown State University, 2024, Department of Civil/Environmental and Chemical Engineering

The 108-mile-long Mahoning River, historically one of the most contaminated rivers in the U.S., contains metals above the EPA aquatic criteria. This study identifies the contamination levels, spatiotemporal patterns, sources, speciation, and bioaccessibility of metals (As, Ba, Fe, Pb, Ni, Zn) in the water and sediment of the lower Mahoning River. Sediment analysis showed that all metals exceeded the Sediment Reference Value, except for Ba. Regression analysis showed a significant decrease of Pb and Fe (p < 0.05) in water from 1993-2021, suggests that the water quality of the river with respect to Pb and Fe is improving comparatively in the past three decades. The contamination factor indicated that metals in water were uncontaminated (< 1), while metals in sediment were moderately to highly polluted (3-15). Inverse distance weighting in sediments illustrated decreasing concentrations towards downstream for Ni, while increasing concentrations towards downstream for As, Ba, Fe, Pb, and Zn in sediment. The inverse distance weighting patterns may be associated with land use, as the river traversed the agricultural region upstream, the urbanized region downstream, and mixed-land areas in the last stretch. Speciation analysis revealed metals in water and sediments were in divalent forms (HM2+), except Pb (PbOH+, PbCO3), indicating high bioaccessibility and potential plant uptake in the aquatic environment.

Master of Science (MS), Ohio University, 2024, Geological Sciences

This study investigates the extent, nature, and formation processes of Paleo Lake Buckeye during the Late Pleistocene, located in the Buckeye Creek watershed in the central Appalachian Mountains. This thesis integrates GIS mapping, field methods utilizing sediment coring and trenching, radiocarbon dating and grain size analysis to reconstruct the margins and depositional environments of Paleo Lake Buckeye and its surrounding landscape. Radiocarbon and optically stimulated luminescence (OSL) dating indicate that the lake formed between 20,000 and 40,000 years ago, coinciding with the peak of the last glacial epoch. The stratigraphic analysis shows fine-grained lacustrine deposits, organic rich layers, and episodic coarse-grained beds, which reflects periods of quiet water deposition interrupted by high-energy events. Paleo Lake Buckeye's formation is linked to periglacial conditions, where freeze thaw cycles mobilized sediments and permafrost dynamics influenced hydrological processes. This research not only interpret the paleoenvironmental conditions of the Buckeye Creek watershed during the Late Pleistocene, but also contributes to broader discussions on glacial and periglacial processes, climate variability, and landscape evolution in the central Appalachian Mountains.

MS, Kent State University, 2024, College of Arts and Sciences / Department of Earth Sciences

Understanding how paleoenvironments and biogeochemical cycles operate in response to local sea-level fluctuations at a time when climatic conditions were warmer, and CO2 was higher than today can help contextualize how the Earth will respond to future warming and sea-level rise. The Cretaceous Straight Cliffs Formation of Utah is an ideal study site to investigate the relationship between sea-level, carbon, and nutrient cycling, as it provides an opportunity to observe the transport and delivery of organic matter (OM) and nutrients across a terrestrial-marine margin. Samples were collected from two cores that span the paleoshoreline of the Western Interior Seaway (WIS) and record locations that oscillate between terrestrial (floodplain, fluvial, peat mires), and transitional (estuarine), and marine (near-shore and offshore) depositional environments. Most of these sediments contain high levels of organic carbon, and as local sea level fluctuated, the two cores experienced variable amounts of marine influence during deposition. Marine influence was greater in the older Calico Sequence as indicated by higher sulfur content. The presence of sulfur during the Calico Sequence led to enhanced pyrite formation and enabled phosphorus to be lost from the system, presumably to the open seaway. During the younger A Sequence, a lack of sulfur and abundant reactive iron in the sediments meant that these marginal environments became effective traps for phosphorus during the younger A Sequence, retaining this critical nutrient in marginal terrestrial environments. These indicate how change in the relative abundance of sulfur in reactive iron rich coastal environments can cause a cascading effect of phosphorus cycling and delivery into the open ocean.

Master of Science in Electrical Engineering, University of Dayton, 2024, Electrical Engineering

Remote sensing techniques are capable of capturing large scenes of data over several sensing domains. Hyperspectral imagery (HSI), often accompanied with lIDAR and orthoimagery sensors during collection, can provide deeper contextual information for a wide range of applications in many different fields. Complex characteristics across spectral bands in addition to high-dimensionality of HSI data present challenges to accurate classification. Generally, dimensionality reduction of the input hyperspectral data cube is performed through multi-phase analytical algorithms as a pre-processing step before further analysis to include machine learning networks. These networks commonly rely on labeled training data for segmentation. Annotating ground truth aerial data can prove to be a cumbersome endeavor that may require specific expertise for accurate assessment. This inspires exploratory research for useful unsupervised feature-learning approaches that can withdraw essential information from HSI data to map scenes without labeled data thereby providing a start-to-finish scene segmentation process.

Master of Science (MS), Ohio University, 2024, Environmental Studies (Voinovich)

The earliest known people in Ohio arrived nearly 13,000 years ago, during a period of climatic instability. Immense volumes of water caused by Late Pleistocene deglaciation left a mosaic of lakes and wetlands covering much of the state. Although no formal tests of intensive use of wetlands are known, optimal foraging models predict that glacially formed kettles, lakes, and wetlands would have been attractive to early hunter-gatherers entering the region. My research tests the expectation that Paleoindians would have focused their subsistence efforts on glacial water features. Using existing datasets from the Ohio Archaeological Inventory, Ohio Fluted Point Survey, and the Ohio Department of Natural Resources Division of Geological Survey, I test three hypotheses about Paleoindian glacial lake and wetland use. The results of statistical tests suggest that glacial water features throughout most of Ohio were favored locations for hunter-gatherers during the Early and Middle Paleoindian Periods. During the Late Paleoindian Period, use of these features declined throughout the state except for the Huron-Erie Lake Plains, where glacial water feature use intensified. The trend of decreasing use of glacial water features throughout the Paleoindian Period may result from decreased productivity in those settings as population increases and fewer wetland caused a shift toward greater diet breadth. My findings add detail to current models of Paleoindian behavior in Ohio and elsewhere. More broadly and with increasing relevance, these findings potentially help to understand human adaptation in the face of climate change.

Master of Science (MS), Bowling Green State University, 2024, Geology

Yearly, millions of tons of sediments are dredged from USA lakes and federal navigation channels to maintain the economic activity of ports and harbors. About 1.5 million cubic yards of dredged sediment are excavated yearly from the Western Lake Erie Basin, Ohio. Following the prohibition on dumping dredged material into open water, the State of Ohio recommends finding several beneficial uses for this material, including using the sediment as farm soil amendment. My research examined the health risk assessment of potential heavy metal contamination in specialty crops grown in soils amended with dredged material. The research objectives were to (1) determine the potential bioaccumulation of organic (PAHs) and inorganic (heavy metals) contaminants in specialty crops, (2) determine the expected daily intake of metals, ecological risk coefficient, health risk index, transfer factor, and their implications in soil and human health, and (3) provide insights on ecological and agricultural implications when dredged sediments are used as farm soil amendment. Our soil blends consisted of 100% farm soil, 90% farm soil/10% dredged sediment, and 100% dredged sediment. The ecological risk assessment index (taking into consideration the metal toxicity) indicated that Pb, As, Zn, Cr, Ni, Co, and Cu were below the threshold value of 40 (unitless). Values below 40 represent lower sensitive toxicity to organisms when exposed to the specific metal. Our results indicated a small translocation of Al, Co, Cr, Fe, Mn, Pb, Ni, and Zn into the edible biomass from the mixture soil as reported by the translocation factor. Only arsenic showed enrichment in the edible biomass across all treatments and crops; however, the enrichment decreased as the dredged sediment ratio increased, except for lettuce in the mixture treatment. We also calculated the health risk index that takes into consideration the reference oral dose (maximum exposure with likely no detrimental effects on human health). The a (open full item for complete abstract)

MS, Kent State University, 2023, College of Arts and Sciences / Department of Earth Sciences

Piping or internal erosion has been responsible for almost half of all dam failures worldwide. In this research, we studied the influence of grain size heterogeneity, as characterized by sediment size (d50) and the uniformity coefficient (Cu), on piping potential. A novel experimental setup was designed in-house that included sediment mass, pressure, and turbidity sensors allowing the examination of transient changes during piping events. Porosity and conductivity were analyzed in order to compare trends across varying grain size distributions. Mass values of soil lost during piping failure via a continuous mass balance and a turbidity meter to capture fines that remain in suspension were both utilized to capture the magnitude of piping failure. Minute Piping and Clogging events that are only able to be captured via the pressure transducers were recorded during this experiment, adding complexity to the onset of piping phenomena. The smaller the Cu, the less clogging events occurred before piping failure. It was noted that these minute piping and clogging events would stabilize as the sediment column reached equilibrium. This research allows for further studies to expand on these piping and clogging events as well as depicted trends between soil heterogeneity and piping potential.

Master of Sciences, Case Western Reserve University, 2024, Materials Science and Engineering

Advanced analytics of diverse geospatial data streams can provide invaluable insights into complex agricultural and environmental systems. This work pioneers an integrated spatiotemporal analysis approach synthesizing satellite imagery, digital soil mapping, hydrological measurements, elevation, and historical crop data. The overarching objective of this work is to quantify relationships between crop growth dynamics, soil properties, nutrient distribution, water quality, and land use patterns. The methodology employs a case study focused on major agricultural regions to show the potential of big data analytic techniques. Custom applications and tools built on distributed computing infrastructure enable the assimilating and processing of massive heterogeneous datasets. The results unveil intricate connections between vegetation indices, soil nutrients, crop types, and nutrient transport, offering strategic perspectives to enhance productivity while minimizing environmental impacts. The multi-faceted understanding achieved fills critical knowledge gaps regarding interactions within agroecosystems. While moderate-resolution regional data provided informative baseline insights, higher spatiotemporal resolution and expanded geographic scope would further strengthen the analysis. Overall, this work underscores the immense potential of data science, geospatiotemporal analytics, and systems thinking to address pressing crop, land, nutrient, water, and soil challenges. The integrated approach provides a powerful paradigm for leveraging emerging data streams toward creating a digital agriculture ecosystem.

Master of Science (MS), Ohio University, 2023, Geological Sciences (Arts and Sciences)

The Rio San Juan (RSJC) and Samana Metamorphic Complexes (SMC) are paleosubduction complexes exposed on northern Hispaniola. The RSJC has previously been classified as an example of a “warm” paleosubduction zone, as it contains metamorphic rocks that record thermal gradients of ~18 °C/km. However, the SMC, which is located ~100 km to the east, preserves lawsonite eclogite, a type of metamorphic rock that only forms under lower geothermal gradients (~ 5 – 6 °C/km). Although the rocks in these complexes have been proposed to form in a common subduction zone, the geologic and tectonic relationships between the high-pressure/low-temperature (HP/LT) metamafic blocks that record different geothermal gradients in these two complexes are debated. To evaluate the temperature-time-composition relationships between the HP/LT rocks in these complexes, bulk-rock major and trace element geochemistry, zircon trace element and U-Pb geochronology, and single trace element geothermometry studies were conducted on blueschist- and eclogite-facies rocks from the RSJC and the SMC. Bulk-rock major and trace element compositional studies of RSJC and SMC metamafic rocks show that they have geochemical affinities to N-MORB and arc-related rocks, indicating that both upper plate and lower plate material was likely incorporated into the subduction zone as a result of subduction erosion processes. Most RSJC and SMC metamafic rocks also record variable enrichments in the LILE that may reflect periods of fluid-rock interaction. Zircons in RSJC and SMC metamafic rocks are scarce, and, when present, generally unzoned. Zircons from a RSJC epidote eclogite record metamorphic ages ranging from ~90 – 125 Ma, indicating subduction-related metamorphism was likely occurring for at least 35 million years. Rare zircon cores preserved in this sample record ages of ~130 Ma that are interpreted as reflecting the age of the protolith. Two zircons recovered from a RSJC retrogressed metama (open full item for complete abstract)

MS, Kent State University, 2023, College of Arts and Sciences / Department of Earth Sciences

Acid Mine Drainage (AMD) is an environmental issue commonly associated with abandoned coal mines and is caused by the weathering of sulfide minerals. Pyrite oxidation is a common contributor to AMD that consumes oxygen and releases Fe and sulfate into surrounding ground and surface water. The temporal and environmental controls on soil gas processes at abandoned mine spoils, where pyrite oxidation and soil respiration occur simultaneously, are not well understood. Studying soil O2 in pore spaces is a potential way to better understand and disentangle these two processes. I collected paired soil O2 and CO2 measurements from an abandoned coal mine site and conducted laboratory incubations to investigate how signals of soil respiration and pyrite oxidation become entangled and whether it is possible to isolate a pyrite oxidation signal. While gas data from laboratory incubations are not directly analogous to field data, there are consistent oxygen consumption signals from pyrite oxidation, but the size of these signals are relatively small. Therefore, it is difficult to detect strong pyrite oxidation signals in the field due to the overpowering influence of soil respiration. Most of the field data was consistent with typical soil respiration. However, I measured a clear pyrite oxidation signal during December 2021, which was characterized by low ARQ values that could not be accounted for by theoretical shifts in substrate consumption. The main finding from this research is that the oxidation of pyrite and sulfide minerals in the Huff Run mine spoils is detectable via gas signals only under certain environmental conditions. This work highlights that many environmental factors can influence the complex soil system of abandoned mine spoils and that soil gasses can provide an important perspective.

MS, Kent State University, 2023, College of Arts and Sciences / Department of Earth Sciences

Numerous experimental and theoretical studies have explored the length-scale dependence of dispersion and dispersivity in different sedimentary porous media, revealing asymptotic dispersion but also a linearly increasing dispersivity with transport length scale. Albeit these transport behavior, defining the Representative Elementary Volume (REV) required to achieve Fickian dispersion in homogeneous porous media remains ambiguous, with very few experimental studies addressing this issue. Additionally, there is insufficient data about the relationship between longitudinal dispersivity (α_L) and flow rate or Peclet number (Pe). In contrast, dispersion is known to depend on Pe through a power law, but we do not know if the reported power-law exponents are impacted by various amounts of non-Fickian characteristics, i.e., Fickian transport characteristics are not ensured in determining the power-law exponents. In this laboratory study, we analyze Breakthrough Curves (BTCs) and Residence Time Distribution (RTD) curves from 900 tracer experiments conducted on a set of two well-sorted homogeneous column packs and a set of three two-layer heterogeneous column packs each of which includes seven different length columns between 0.6 ft and 6 ft. Our analysis shows that when the transport length scale increases, there is a distinct transition from non-Fickian to Fickian transport characteristics. From transport in different length columns, we determine power-law exponents of Pe-dependent dispersion and dispersivity highlighting how the exponents are affected by various degrees of non-Fickian transport characteristics., i.e., from the pre-asymptotic to the asymptotic regime. The power-law exponents exhibit a decreasing trend with an increase in transport length. For example, the well-sorted sand exhibit exponent of 1.55 in the non-Fickian regime at 0.6ft and converges to a value of 1.0 in the Fickian regime from the 6ft column. In the well-sorted media, the inclusive graphical (open full item for complete abstract)

Master of Science (MS), Bowling Green State University, 2023, Geology

In the last decades, the Western Lake Erie Basin (WLEB), USA, has been experiencing harmful algae bloom (HABs) events attributed to the large export of phosphate (PO4-3) and nitrate (NO3-) loads into waterways from farmland. There is current concern about exacerbating the HABs at the WLEB by discarding dredged materials (DM) in open lake waters. The State of Ohio has prohibited open lake water disposal, and it is requesting beneficial uses for the DM, and this study is exploring amending farm soil with DM. Previous research has demonstrated benefits on soil health when Hoytville soil was amended with DM from Toledo Harbor, OH, as the DM contains adequate soil organic matter (SOM) and calcium content. This study aimed to characterize the SOM in the DM by conducting a gentle chemical sequential extraction named Humeomics. Total organic carbon, total phosphorous, total nitrogen, and organic moieties associated with the SOM organo-soluble and hydro-soluble extracted fractions were characterized. Emission and excitation matrices were collected and paired with Parallel Factor analysis (PARAFAC) to characterize SOM fluorophores. The organo-soluble fractions exhibited terrestrial humic-like, terrestrial fulvic-like, and microbial tryptophan-like components. The hydro-soluble fractions showed microbial and humic-like and terrestrial or freshwater humic-like components. TOC concentrations in the organo-soluble and hydro-soluble fractions ranged from 594,022 to 483,723 mg kg-1 and 299,777 to 60,830 mg kg-1, respectively. Total phosphorus in the organo-soluble and hydro-soluble fractions ranged from 920.32 to 509.94 mg kg-1 and 31,389 to 182 mg kg-1, respectively. And total nitrogen in the organo-soluble and hydro-soluble fractions ranged from 11,614.47 to 2,879.86 mg kg-1 and 16,505.86 to 4,087.97 mg kg-1, respectively. Fourier-transform infrared spectroscopy analysis confirmed the presence of O-H (3400 cm-1), carbonyl (1720 cm-1), alcohol (3600-3000 cm-1), alkane (2915cm-1), (open full item for complete abstract)

Master of Science (MS), Wright State University, 2023, Earth and Environmental Sciences

Estimating sediment thickness and bedrock surface geometry is critical for many hydrogeologic studies. The horizontal-to-vertical spectral ratio (HVSR), a passive seismic method is a unique, non-invasive technique for speedily estimating bedrock depth. To record ambient seismic noise, the H/V method employs a single broadband three-component seismometer. A field assessment was conducted on the Wright State University Campus in Dayton, Ohio, to determine the depth (z) and elevation of the bedrock. Data were collected at 60 different locations. A known value for the depth of bedrock on campus was determined using the log from a local water well available from the Ohio Department of Natural Resources. Using this depth and the observed fundamental resonant frequency (f0) the shear wave velocity (Vs) of the glacial drift above bedrock was calculated, which was then used to determine the depth of bedrock and its elevation in relation to the fundamental resonant frequency (f0). The HVSR results generally produced distinct, easily discernible resonance frequency peaks which together with the Vs constrained at the local borehole allowed the depth to bedrock and thereby bedrock elevation to be mapped across campus. The interpreted depth and elevation of the bedrock surface are comparable with previous surveys on campus.

Master of Science, University of Akron, 2023, Geology

Within the mid to lower continental crust distributed ductile thinning occurs, in orogens that form mountains like the Himalayas and Appalachia, due to a weak middle to lower crust that deforms laterally in response to loading of a thickened, cold upper crust. This thinning destabilizes large orogens and causes the exhumation of hot and weak rock from the mid to lower crust that begins to partially melt. This melting further weakens the rocks and may affect the deformation mechanisms operating in the crust. Melting has been seen to have impacts on the deformation mechanisms and resulting lattice preferred orientations (LPO) that form in olivine-basalt aggregates (Holtzman et al., 2003). To investigate the effects of partial melting on deformation mechanisms and LPO development in two common foliated felsic rocks, I performed general shear deformation experiments on a fine-grained quartzite and fine-grained gneiss at T = 800°C, 850°C, 900°C, 950°C, or 975°C, P = 1.5 GPa, and strain rate of 6*10-5/s. The quartzite (grain size ~30 microns) is composed of 90% quartz and 10% muscovite. The fine-grained gneiss (grain size ~50 microns) is composed of 43% quartz, 40% plagioclase, 16% biotite, and 1% accessory minerals. The foliation in the slices of each rock was oriented parallel to the shear plane between Al2O3 shear pistons with a cut made at 45° to the compression direction. Experiments were performed at a range of temperatures to change the melt fraction present in the rocks during deformation (Melt = ~0%, 0.25%, 0.5%, and 1%). The yield stress of Moine Thrust quartzite decreased as a function of increasing temperature from ~1000 to ~300 MPa. However, all the experiments with melt present (T equal to to greater than 850°C) significantly strain hardened after a shear strain (g) of 1. This hardening may be due to the presence of melt along grain boundaries which is absorbing water from the recrystallizing quartz grains which slows diffusive recovery in quartz. The Gne (open full item for complete abstract)

Master of Environmental Science, Miami University, 2023, Environmental Sciences

Northwest Indiana has a long history of industrialization, especially within the automobile and steel sectors. Due to its geolocation, the Indiana Dunes National Park is at the receiving end of these industries' emissions, particularly from Technogenic Magnetic Particles (TMPs). This study investigated sand from Mount Baldy as a potential collector of TMPs emitted from steel facilities within and near Indiana Dunes National Park. Representative samples of sand were collected on Mount Baldy and the Lakeshore, while street sediments were collected in Michigan City and Gary, Indiana, for comparison. Sample analysis was done using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques, both equipped with Energy-Dispersive X-ray Spectroscopy (EDS). Results revealed the presence of Fe, Ti, Va, Zn, Cr, and Mn among heavy metals, rare earth elements (REE), and Mn-rich Spherules. The results mainly showed the presence of Fe-oxides particles in the sand, which may be attributed to industrial activities in the surrounding area. These findings provide relevant information on the capacity of sand to capture pollutants and suggest further studies to quantify TMPs, mitigate the potential impact of industrialization, and raise awareness of the need to strengthen pollution standards to protect the environment, visitors, and residents.

MS, Kent State University, 2023, College of Arts and Sciences / Department of Earth Sciences

The Neuse River Estuary is a shallow open estuary located at the southern margin of the Albemarle-Pamlico Sound complex in North Carolina. Nutrient oversaturation due to the delivery of excessive nutrient-rich alluvial flux, weak tidal activity, and long water residence times have led to eutrophication and the growth of seasonal algal blooms. The problem has become more severe over the past few decades leading to many environmental and social health concerns. These outcomes emphasize the need for regular monitoring of phytoplankton, growth rate, water quality change, and control strategies. Satellite remote sensing studies provide a great solution for continuous water quality monitoring as a relatively cost-effective tool with high spatial and weekly to daily cloud-free temporal resolution. This research applies the Kent State University (KSU) Varimax-rotated Principal Component Analysis (VPCA) developed by Ortiz et al. (2013) to study the seasonal succession of phytoplankton and water quality parameters in the Neuse River Estuary by using Sentinel - 2 A/B Multi-Spectral Instrument (MSI) images from 2019 to 2021. The spectral signals in the water column were decomposed into six components using coherent, linearly correlated information in the visible and near-infrared spectral ranges. The components are then identified by comparing their spectral shape against standard spectral libraries. The study collaborated with the Neuse River Estuary Modeling and Monitoring program for the field-based water quality and cell count data, which was used in conjunction with remote sensing observations. We evaluated the applicability of the KSU VPCA method through a three-day average model. It identified two phytoplankton assemblages (Diatoms/Dinoflagellates/Chlorophytes and Cryptophytes) and two minerals (Goethite and Muscovite) that are successfully matched with the field observations. Secondly, we separated three phytoplankton-related (Dinoflagellates, Diatoms, and Chloroph (open full item for complete abstract)

Master of Science, University of Akron, 2022, Geology

In northern Ohio a complex aquifer system includes a surficial glacial drift aquifer and a carbonate bedrock aquifer. The bedrock aquifer carries regional flow and discharges through karst springs near and in Sandusky Bay. This investigation employed quarterly comprehensive geochemical analyses along with high-resolution temperature/ conductivity monitoring in the discharge zone at Castalia Blue Hole, Miller's Blue Hole, and a flowing artesian well to give a better understanding of the groundwater system. Nutrient input to Lake Erie from the karst springs was also determined. In addition, the paleohydrology of the system under changing ice conditions and lake levels was explored. Temperature and electrical conductance were monitored at 15-minute intervals. Water samples determined major ion chemistry, agrichemicals, and nutrients. A paleocross-section was constructed based on ice sheet thickness to determine paleo recharge history to evaluate past groundwater flow. The regional water flows from potentiometric high areas in Logan and Morrow Counties towards Sandusky Bay. Groundwater recharge would formerly have taken place under the ice sheet, driving flow southward, which is opposite of modern-day flow. Low seasonal variation in chemistry suggests that the groundwater comes from a regional source and that the aquifer behaves as a diffuse medium. Further evidence is relatively invariant water temperature over the sampling period. Measured temperatures at the 3 sites differ, partially due to challenges with appropriate deployment. Specific conductance is high and relatively stable, but varies between sites with Miller's Blue Hole having the highest variability and Stidham Well the least. Miller's Blue Hole and Stidham Well are close in values for specific conductance but range differently for temperature from 7.65-12.56°C and 12.00- 12.12°C respectively. Small dips in specific conductance correlate with precipitation and sugge (open full item for complete abstract)

Master of Science (MS), Bowling Green State University, 2022, Geology

The Western Lake Erie Basin (WLEB) has been experiencing harmful algal blooms due to increases in dissolved reactive phosphorous (DRP) from agricultural land in the Maumee River watershed. Agricultural best management practices (BMPs) can be useful to mitigate the DRP loads; nevertheless, DRP is not always fully removed by in-field BMPs. Phosphorous (P) removal structures can be filled with phosphorus sorption materials (PSM) such as iron and aluminum oxides and can be placed at the junction of runoff and subsurface drainage to trap DRP from tile drainage. However, dissolved organic matter (DOM) from the agricultural farmland might compete with phosphate ions (PO43-) at the adsorption sites in the media, reducing its lifetime and efficiency. Therefore, laboratory flow-through column experiments were conducted to determine whether DOM is affecting P sorption onto iron enhanced activated alumina media (Alcan). The experiments were informed by field data collected from a regional farm. Alcan (Al/ Fe (hydro) oxides) media was efficient in removing PO43- coming into the filtering system and thereby, flow-through column experiments were able to determine a discrete P removal percentage efficiency of 83.32%, 68.26%, 66.54%, 57.16% and 41.27% by the end of treatment I (5mg L-1 PO43- only), treatment II (5mg L-1 PO43- and 5 mg L-1 DOM), treatment III (5mg L-1 PO43- and 10 mg L-1 DOM), treatment IV (5mg L-1 PO43- and 20 mg L-1 DOM), and treatment V (10mg L-1 PO43- and 20 mg L-1 DOM), respectively. Moreover, from exponential regression analysis of P removal curves for each treatment, it was measured that a total cumulative of 231.45 gm, 92.65 gm, 92.06 gm, 65.998 gm and 91.476 gm of P per kg PSM can be added to treatment I, II, III, IV and V, respectively, until the media gets fully saturated, i.e., concentration of influent PO43- would be equal to the effluent PO43- concentrations. It is evident that DOM is competing with PO43- decreasing PO43- sorption onto the Alcan media. (open full item for complete abstract)

Master of Science (MS), Bowling Green State University, 2022, Geology

Lead (Pb) introduced by anthropogenic activities is a prominent ongoing environmental concern especially for young children who can ingest it directly through hand-to-mouth activities and are most susceptible to the harmful lifelong effects of Pb poisoning. This study involved determining Pb concentrations in soil cores sampled from the surface to root depths at community garden sites in the Toledo, OH area. While these gardens have many positive effects on their communities, they provide a potentially ready source of Pb to children and adults. A total of 277 soil samples were analyzed from nine different community garden sites, six of the sites had soils with Pb concentrations above background levels and three had soils with Pb concentrations exceeding the USEPA action level of 100 ppm. The sites with elevated Pb levels were located in socioeconomically depressed older neighborhoods and the soils that had actionable Pb levels were from present or prior drip zones. The primary source of the Pb being from past use of Pb-based paints. The Pb concentration varied with depth typically increasing at the base of raised beds due to mixing with underlying original soil. The vertical transport of the Pb is due to mechanical processes associated with gardening practices. Community outreach was an important component of this study and the results were presented individually to the garden managers along with recommendations on how to minimize Pb exposure at those sites that had soils with elevated Pb levels. The most important considerations being to identify and avoid drip zones and to collect not just surface samples but also down to root depths.