Master of Science, University of Toledo, 2021, Geology

Recent research investigating the contributions of non-point legacy dissolved reactive phosphorus (DRP) sources to DRP loading in the Maumee River watershed has relied heavily on edge of field methods. While edge of field methods consider the hydraulic and chemical parameters of tile drainage and overland flow, these studies neglect to consider the field-scale groundwater flow regimes which control the mobilization and advection of DRP to tile drains. Understanding the field-scale advective capacity of groundwater can aid in the assessment and modeling of the impacts of legacy sources on watershed DRP loading. A tile drained farm field with legacy soil P accumulation resulting from decades of biosolid applications within the Maumee River watershed was selected as a study site to evaluate the advective capacity of two groundwater flow regimes: rapid return flow (RRF) and slower groundwater baseflow (SBF). 15 piezometers were installed throughout the farm field to characterize the unconfined aquifer, monitor the potentiometric surface, and permit groundwater sampling. Hydrograph separation of piezometer and tile drain hydrographs yielded the RRF and SBF components of groundwater and tile discharge. The legacy P source in the soil profile was characterized by sampling the soil profile at increasing depths. Results show significant legacy soil P accumulation in the near surface soil profile (100-300ppm soil test phosphorus, 0-60cm), with a stratification of concentrations that decreased as depth in the soil profile increased. Elevated groundwater DRP concentrations observed after recharge indicate that gravity drainage is mobilizing legacy P sequestered in the soil profile. The RRF component of piezometer hydrographs was found to transport considerably less DRP than SBF, accounting for 13% of total discharge and 11% of DRP mass transported. This regime dynamic was also present in groundwater and tile drain discharge as baseflow. The total DRP mass discharged by (open full item for complete abstract)

Master of Science, University of Toledo, 2018, Biology (Ecology)

A principle driver of water-polluting harmful algal blooms (HABs) in agricultural watersheds is fertilizer phosphorus (P) runoff from farm fields. Because P is essential to plant growth, eliminating P application is infeasible. However, much of the P that is added to soils as fertilizer binds tightly to soil particles and is relatively unavailable to plants. In natural systems, microbial and faunal decomposers can increase soil P availability to plants. In agricultural systems, stimulating these organisms may help maintain P availability with decreased P application rates, thereby increasing P application efficiency while reducing runoff potential. We tested the hypothesis that stimulating soil fauna with sodium (Na+) and microbes with carbon (C) would increase soil P availability to plants. We added corn stover and Na+ solution to plots in conventionally-managed corn fields in Northwest Ohio. Stover treatments increased microbial biomass and activity and Na+ and stover combined increased soil faunal activity. However, even in both control plots and plots with stimulation of soil microbes and fauna, soil biological activity was low, and was not correlated with P availability. Therefore, in fields with low levels of decomposer activity, organisms may play a limited role in soil P cycling. In these types of ecosystems, treatments to stimulate decomposers already in those systems may be ineffective in reducing P runoff potential, at least in the short term.

BS, Kent State University, 2024, College of Arts and Sciences / Department of Biological Sciences

Wetlands act as a filter between the terrestrial land and a body of water, regulating the flux of nutrients between these. An overabundance of nutrients, such as phosphate, can lead to a harmful algal bloom (HAB), which is known to deplete oxygen from aquatic ecosystems and produce harmful toxins. The goal of this study was to determine the effect of different vegetation patches on the amount of bioavailable phosphorus, measured as soluble reactive phosphate (SRP), in both the surface water and sediment. We sampled surface water and sediment from Turtle Creek Bay located in Magee Marsh Wildlife Area, Ohio, where we identified four distinct vegetation patches: grasses, hardwoods, Typha spp. (cattail), and submerged aquatic vegetation (SAV). Results of this study showed that the SAV patch exhibited significantly less SRP than the other patches (p<0.05). However, there was no significant difference in SRP concentrations for the rest of the patches. Additionally, we experimentally incubated intact sediment cores sampled from a diagonal transect across Magee Marsh. The cores were incubated with four different SRP concentration treatments based on in situ SRP measurements. We found that at ambient SRP concentrations (4 ug/L), sediments released 455.2 ± 518.3 ug SRP/m2/d into surface waters, but when SRP concentrations in the surface water increased (to 18, 39, and 60 ug SRP/L), sediments removed SRP at increasing rates (-919.9 ± 278.7, -2062.3 ± 1001.61, -7378.5 ± 4267.1 ug SRP/m2/d, respectively).The increasingly negative mean flux rates suggest that these coastal wetland sediments can sequester increasing amounts of SRP as surface water concentrations increase.

Master of Science (MS), Ohio University, 2023, Environmental Studies (Voinovich)

Agricultural nutrient pollution is a significant cause of impairment in American surface waters. Wetland restoration projects in agricultural watersheds can provide an effective sink for excess nutrients and potentially improve downstream water quality. Ohio University has partnered with The Stream and Wetlands Foundation to conduct water quality monitoring during the restoration of Bloody Run Swamp, a wetland in a former agricultural field near Columbus, Ohio. This thesis serves as an analysis of the initial water quality impacts of this restoration project. The restoration of Bloody Run Swamp did not significantly impact total dissolved phosphorus, orthophosphate, TKN, or ammonia concentrations. In contrast, both nitrate/nitrate and total dissolved nitrogen concentration and loads were significantly reduced during construction. This may have been due to the dry weather during construction and the removal of drainage tiles from Bloody Run Swamp. Future water quality monitoring is needed to determine the long-term impacts of this restoration project.

Master of Science, The Ohio State University, 2022, Food, Agricultural and Biological Engineering

Agricultural nutrient loss in the Western Lake Erie Basin (WLEB) leads to elevated nutrient levels in Lake Erie, resulting in harmful algal blooms and anoxic conditions, decreased fish populations, and reduced recreation and tourism revenues. To combat this issue, the Ohio Phosphorus Task Force set a goal to decrease the phosphorus (P) load to the WLEB by 40% from 2008 spring loads. To meet this goal, efforts are underway to minimize the amount of P transported from agricultural fields to surface water using best management practices (BMPs). While many BMPs aim to decrease P loss by optimizing agricultural nutrient usage, some fields continue to have elevated soil test phosphorus (STP) levels even when nutrients have not been applied for decades. These fields, referred to as legacy P fields, contain more P within the soil profile than agronomically necessary and have substantial nutrient runoff potential. Because these sites disproportionately contribute to nutrient runoff, it is important to determine what variables impact and how best to manage nutrient loss from legacy P fields. Rainfall depth and intensity have been identified as driving factors causing P runoff from fields within agronomic STP levels. Better knowledge of the impact of precipitation and temperature on runoff from legacy P fields will improve management to minimize nutrient loss from these unique settings. This is especially valuable information as production and water quality management adaptations are made in reaction to climate change. To determine how weather variability impacts P runoff from legacy P fields, water quality and water quantity data was collected at 11 fields with Mehlich-3 P STP > 100 mg/kg in northwest Ohio for a total of 18.5 site-years, during which time 477 storm events each with > 6.35 mm (0.25 in) of precipitation were monitored. This study found that average nutrient concentrations within tile discharge from legacy P fields were 2.4 times (total P; TP) and 4-5 times ( (open full item for complete abstract)

Master of Science, The Ohio State University, 2019, Environmental Science

The Tri-State Fertilization Recommendations were published in 1995 and have provided a framework for phosphorus (P) and potassium (K) nutrient management in field crops. Due to changing soil properties, management practices and advanced crop genetics, there is a need to reassess plant tissue analysis using current soil conditions and modern hybrids. The Tri-State Fertilizer Recommendations use early reproductive leaf nutrient concentrations as a diagnostic of crop nutrient status and grain nutrient concentrations are the basis of fertilizer rates to replace nutrients lost at crop harvest. An evaluation of these nutrient levels in grain and plant tissue samples are therefore important when revising fertilizer recommendations. The goal of this thesis was to evaluate the how crop nutrient levels, especially P and K, are influenced by key soil and management factors. Specific objectives of Chapter 1 were to determine the effects of i) soil test P and K levels and ii) P and K fertilization on early reproductive leaf and grain P and K concentration of corn, soybean and wheat. The specific objective of Chapter 2 was to report grain nutrient concentration and nutrient removal rates in corn, soybean and wheat in Ohio. On-farm P and K fertilizer strip trials in corn, soybean and wheat were conducted at 262 sites in 39 counties across Ohio from 2014 - 2018. At each site, experiments were conducted using a randomized complete block design with 3-4 replications with two treatments, a P or K fertilization treatment and a non-fertilized control. Routine soil nutrient analysis before fertilization, nutrient concentrations in leaves at early reproductive stages, grain yields and grain nutrient concentrations at harvest were measured at each trial. Key site management practices were also recorded through a survey. The effect of soil test P and K level on plant tissue nutrient concentrations was assessed by using regression analysis. Fertilization effects on tissue nutrient concen (open full item for complete abstract)

Master of Science, The Ohio State University, 2017, Food, Agricultural and Biological Engineering

Phosphorus is an essential nutrient for life, but excess phosphorus in runoff from manure applied to agricultural fields can lead to negative environmental impacts such as harmful algal blooms. Water-extractable phosphorus (WEP) is correlated with phosphorus runoff from land-applied manure, but can change depending on the water content of a sample. Understanding how total phosphorus (TP) and WEP partition through livestock manure management systems can aid attempts in preventing phosphorus pollution of watersheds by increasing knowledge of how to remove it at its source. A number of dairy farms use solid-liquid separation in order to make the manure easier to handle. This produces a mostly solid material which can be re-used in the dairy barns as bedding for the cows, as well as a mostly liquid material which is applied to the fields. However, little is known about the partitioning of WEP through solid-liquid separation. This study investigated the partitioning of TP and WEP through manure management systems on two dairy farms using screw presses and anaerobic digestion to treat the manure produced by the dairy cows. Samples were taken at various stages throughout the manure management systems, to determine important characteristics at each stage. Manure followed two main paths: direct solid-liquid separation of manure diluted with liquid effluent from the separators, or anaerobic digestion of the diluted manure before solid-liquid separation. On Farm B, the liquid effluent of the separators could only be accessed after the streams mixed together, causing difficulties in analyzing the potential for phosphorus removal in each separator individually. Measurements at all important management points on Farm A were available, however, and analysis of those results shows that phosphorus partitioned into the separated solid effluent stream from the separator at a higher proportion than would be expected if the phosphorus partitioned in the same way as the liquid manure (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Doctor of Philosophy, The Ohio State University, 1955, Graduate School

Master of Science (M.S.), University of Dayton, 2015, Chemistry

Polyurethane foams, a class of materials renowned for durability and ease of production, also represent a significant fire hazard through their inclusion in such ubiquitous consumer goods as carpet underlay, mattresses, and furniture. These foams ignite easily, burn at incredible rates, and release enormous amounts of vision-obscuring smoke. This smoke, due to several additives, can carry highly toxic molecules, such as carbon monoxide and hydrogen cyanide, if fire conditions are conducive to such species. Flame retardants are required by law to slow the spread of flame, and the largest class in use are halogenated flame retardants, particularly additive brominated varieties. The use of these additives has presented some environmental hazard when select species have known persistent/bioaccumulation/toxicity (PBT) issues and they migrate into the environment during long-term use or improper disposal. Over the last several years, states and federal organizations have banned some flame retardants, ushering in a need for new such materials, especially reactive flame retardants based on phosphorus. Reactive flame retardants incorporate themselves into the polyurethane via covalent bonds, and cannot easily leach out of the product during its lifetime. Such use of reactive flame retardants should mitigate environmental hazards and eliminate PBT issues for those flame retardants. Thus, the purpose of this project was to develop and standardize procedures for two novel phosphorus-containing, non-halogenated flame retardants, a phosphate and a phosphonate; study their incorporation into longer oligomer-based diols; and fully characterize such diols using hydroxyl value titrations, proton and phosphorus NMR, elemental analysis, MALDI-TOF mass spectroscopy, and viscosity studies.

Master of Science (MS), Wright State University, 2015, Earth and Environmental Sciences

Stream water quality is increasingly threatened by expanding anthropogenic activities, mainly through point source discharges and urban and agricultural runoffs of contaminants getting through a water body's watershed resulting in pollution. Concerns developed as to whether urban or agricultural type activities were causing most water quality impairment issues in the upper Little Miami River watershed in southwest Ohio. Characterizing the upper Little Miami River (LMR) watershed with respect to water chemistry and Land Use/Land Cover (LULC) while evaluating the sources of any higher than expected natural parameter concentrations, with a strong emphasis on the nutrients phosphorus and nitrate, serves as this study's purpose. Efforts are made to determine the greatest non-point source nutrient contribution by specific LULC type watersheds and compare findings with known point source nutrient contributions. Up to 23 sites were sampled during dry weather conditions covering all seasons except winter, ranging from July 2009 to November 2010. Sampling began near the head works of the upper LMR watershed at LMR mile 102, site #1 and ended with site #23 at LMR mile 51.3. Data obtained from the analysis of these samples has been comparatively graphed, spatially and statistically analyzed, and worked into loading calculations for comparisons to available online data, such as point source information. General water chemistry measurements show trends of specific ion concentrations, such as sodium and chloride, in relation to LULC drainage areas connected to sampled pour points. Nutrients such as phosphorus and nitrate have concentration amounts significantly influenced by non-agricultural anthropogenic activities. Statistical analyses of the generated data support the observed trends through correlation coefficients. Estimated stream/river flows at the sampled sites provide loading value development of specific parameters that further support significant trend (open full item for complete abstract)

Master of Science, The Ohio State University, 2012, Nutrition Program, The Ohio State University

Abstract Serum phosphorus is a challenging mineral to manage in kidney hemodialysis (HD) patients. Excess phosphorus has been significantly associated with all-cause vascular and fracture-related hospitalizations, calciphylaxis, and death. When diet alone is not sufficient to manage increased serum phosphorus, phosphorus binders are prescribed to manage serum phosphorus. Non-adherence to prescribed medication regimen, also an on-going challenge, has been associated with unmet expected outcomes and increased risk to the health and quality of life of the patient. The primary objective of this research was to determine the effect of an environmental reminder on the correct and consistent use of phosphorus binders. A study based on the Quasi-Experimental Design was conducted between Oct 2011 and Feb 2012 at an outpatient HD clinic in Columbus, Ohio, USA. Nineteen patients met inclusion criteria of: serum phosphorus greater than 5.5 mg/dL, a prescribed phosphorus binder, in control of their own medication dosing regimen, and receiving HD greater than or equal to six months. All completed the data collection period of the study. Study participants were given an environmental reminder intervention. No statistically significant change in the two months pre Qm comparisons using a CI 0.95, significance <0.05 (0.072 and 0.131, respectively) were identified. In the first month post Qm, a statistically significant change (p= 0.005) was identified. In the second month post Qm, a statistically significant change (p=0.022) was also identified. The change, though statistically significant, did not demonstrate an improvement in serum phosphorus levels as they actually increased rather than decreased after the intervention. As the study was conducted over three major annual holidays, diet was not controlled, and sample was small, the effect of the intervention may have been minimized. Study participants (71.4%) responded in the Exit Survey that the intervention helped them to (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2006, Evolution, Ecology, and Organismal Biology

Lake Erie is facing many perturbations. This study focuses on two issues, the external phosphorus loading and dreissenids' invasion, and investigates the interactions of the responses of the lower trophic levels to these two stressors. I construct an ecological model, EcoLE, based on a USEPA two-dimensional hydrodynamic and water quality model, CE-QUAL-W2. Data from the field year 1997 are used to calibrate the model, while data from 1998 and 1999 are used for verification. There is a good agreement between the modeled and field-measured state variables, and EcoLE catches the major characteristics of the physical, chemical and biological processes found in Lake Erie. We are confident in using this model for qualitative analysis, but one should be cautious in using it for quantitative predictions of Lake Erie processes. When I turn off the turbulent mixing processes, total dissolved phosphorus (TP-F) becomes concentrated in the lower water strata and diatom biomass decreases dramatically. When I turn on the mixing processes again, there is more TP-F in the upper water strata but less TP-F accumulated in the whole water column, because non-diatom edible algae (NDEA) and diatoms become more abundant in the water column. Blue-green algae are less affected by hydrodynamics but depend on the amount of available phosphorus in the whole water column. When I turn off the chemical and biological processes, external TP loads are distributed throughout the western basin and the west central basin as a result of physical mixing. External TP loads have minor direct effects on the east central and the eastern basins, where up to 60% of the daily algal P-demands come from SRP released by organic matter decomposition and by algal and crustacean P excretion. Dreissenid mussel daily grazing impact is less than 10% of the NDEA and diatom biomass in the western basin, and only 1-2% in the central and eastern basins. Impacts of dreissenid nutrient excretion become more important than the (open full item for complete abstract)

MS, Kent State University, 2013, College of Arts and Sciences / Department of Biological Sciences

Water resource managers have been struggling to reverse the negative effects of eutrophication in Lake Erie since the late 1960s. Despite the early successes obtained through reducing external phosphorus (P) loads, excess algal growth dominated by species of Microcystis and Cladophora now consistently plagues the lake each summer. One potential explanation is described by the nearshore phosphorus shunt hypothesis, which contends that the filter feeding activity of invasive dreissenid mussels has significantly altered the flow of P from nearshore to offshore depths. Using this hypothesis as a framework for our research, we believed that we would find evidence of intensified P deficient conditions in the photic zones of offshore sites compared to those of nearshore sites. Water samples were taken from eight transects located along the southern coastline of Lake Erie in the late spring and early fall of 2011 and 2012. Three P deficiency indicator assays were conducted, including P turnover time, P debt, and alkaline phosphatase activity (APA). Overall, we found that seasonality, rather than depth, was a more significant factor in determining P deficiency, with a higher incidence of P deficient conditions occurring in the fall than in the spring. In 2012, we also utilized two additional assays, nitrogen (N) debt and ammonium enhancement response (AER), to determine if N limitation or co-limitation by N and P could be occurring in Lake Erie, in spite of the long-held paradigm that temperate freshwater systems are limited solely by P. Evidence of N deficiency was more frequently found at the beginning of the growing season despite higher concentrations of bioavailable N, while incidents of phosphorus deficiency increased towards the season's end. A seasonal decline in soluble reactive P was likely the driving force from N deficient conditions to P deficient conditions. The results of this study provide evidence that algal growth in Lake Erie is not limited solel (open full item for complete abstract)

MS, University of Cincinnati, 2024, Engineering and Applied Science: Environmental Engineering

Phosphorus pollution is a major water quality issue impacting the environment and human health. Traditional methods limit the frequency and extent of total phosphorus (TP) measurements across many rivers. However, remote sensing can accurately estimate riverine TP; nevertheless, no large scale assessment of riverine TP using remote sensing exists. Large-scale models using remote sensing can provide a fast and consistent method for TP measurement, important for data generalization and accessing extensive spatial-temporal change in TP. Our study uses remote sensing and machine learning to estimate the TP in rivers in the contiguous United States (CONUS). Initially, we developed a national scale matchup dataset for Landsat detectable rivers (river width >30m) using in situ TP and surface reflectance. We used in-situ data from the Water Quality Portal (WQP), alongside water surface reflectance data from Landsat 5, 7, and 8 spanning from 1984 to 2021. Then, we used this dataset to develop a machine learning (ML) model using different preprocessing methods and algorithms. We found that using high-level vegetation in the clustering approach and over-sampling or under-sampling our training data in the sampling approach improved our model estimation accuracy. We compared XGBLinear, XGBTree, Regularized Random Forest (RRF), and K-Nearest Neighbors (KNN) ML algorithms and selected XGBLinear as the best model with an R2 of 0.604, RMSE of 0.103 mg/L, MAE of 0.83, and NSE of 0.602. Finally, we identified human footprint, elevation, river area, and soil erosion as the main attributes influencing the accuracy of estimated TP from the ML model.

Master of Science, The Ohio State University, 1951, Graduate School

Master of Science, The Ohio State University, 1925, Graduate School

Master of Science, The Ohio State University, 1913, Graduate School

Master of Arts, The Ohio State University, 1923, Graduate School

Master of Science, University of Akron, 2024, Civil Engineering

Compost blankets have been used as a management practice over highway slopes, especially with disturbed soils, to mitigate runoff and soil erosion. However, it is yet to be employed in Ohio due to lack of research and specifications. This research focused on efficiency of 1”, 1.5” and 2” of Biosolids and Yard-waste compost blanket over 6:1 and 4:1 slope of disturbed soil in a lab-scale rainfall simulation, followed by field study on 1.5” Biosolids and Yard-waste. The assessment of vegetation coverage showed that Biosolids significantly outperformed both Yard-waste and control treatments (p<0.05). Grass density and health were notably better in Biosolids, although increasing compost thickness did not proportionally improve vegetation growth. Both Biosolids and Yard-waste effectively reduced runoff generation, with 2” Biosolids performing the best by reducing runoff volume by 96% to 98%. Compost blankets reduced total suspended solids (TSS) significantly compared to controls (p<0.05), particularly 2” Biosolids, which released the least TSS with almost 99.99% reduction. For Soluble Reactive Phosphorus (SRP), 2” Biosolids were the most effective treatment in reducing losses by 92% to 96% than control cases. Nitrate loss was not significantly reduced by any treatments on the 6:1 slope, but 1.5” Yard-waste (98%-99% reduction) and 2” Biosolids (86%-95% reduction) performed better than other treatments on the 4:1 slope. Both Biosolids and Yard-waste showed reduced Total Nitrogen (TN) and Total Potassium (TK) release compared to controls. With 98% to 100% TN reduction, 1” Yard-waste performed better than other treatments in both slopes. For TK, 1.5” Yard-waste had the highest reduction of 91% in 6:1 slope, but for 4:1 slope it was 1” Yard-waste with 84% reduction. Field tests compared 1.5” Biosolids and 1.5” Yard-waste with vegetated and unvegetated control cases, which demonstrated healthy vegetation growth in Biosolids within six weeks, requiring trimming to adhere to guid (open full item for complete abstract)