Physical Sciences and Mathematics Commons^™

Quantification Of Septic System Contribution To Nutrient Loads In Surface Waters, Archana Tamang

Electronic Thesis and Dissertation Repository

Freshwater systems worldwide are threatened by excessive nutrient (nitrogen and phosphorus) loading. This study evaluated the contribution of septic systems to stream nutrient loads in nine subwatersheds. Stream sampling was conducted during low and high discharge conditions, with samples analyzed for total phosphorus (TP), soluble reactive phosphorus (SRP), nitrate (NO₃-N), and acesulfame (ACE; wastewater tracer). Higher septic effluent reached the subwatershed outlets during high discharge conditions. Subwatersheds with newer households had a lower percentage of septic effluent reaching the stream compared with subwatersheds with older households. Seasonal and event-based ACE concentration-discharge relationships revealed that the hydrological pathways delivering …

A Regional Chemical Characterization And Analysis Of Groundwater In Eastern Ontario, Laura M. Colgrove

Electronic Thesis and Dissertation Repository

This study utilizes 234 samples to provide a regional characterization and analysis of groundwater chemistry in eastern Ontario, Canada, where elevated TDS, Na and halogens occur in shallow groundwater. Water-types, PCA and mapping are used to investigate the processes and features controlling the chemistry. The chemical patterns are associated with glaciomarine deposits (extent, thickness) and bedrock topography, which modulate residence time and flow-path of groundwater. These determine the relative effects of recharge, ion exchange, salinization and organic breakdown on groundwater chemistry. Anomalous chemistry east of Ottawa (brackish-to-saline TDS; elevated water δ¹⁸O; elevated Na, Cl, I, CH₄, …

Silver Nanoparticle Transport Through Soil: Illuminating The Governing Pore-Scale Processes, Ian L. Molnar

Electronic Thesis and Dissertation Repository

Engineered nanoparticles are widely used and will eventually be released to the subsurface environment and contaminate groundwater resources. However, the transport of engineered nanoparticles through soil is currently not well understood and cannot be modelled in any fundamental manner, placing groundwater resources at risk from nanoparticle contamination. This inability to accurately simulate transport is due to a lack of experimental information on nanoparticle interactions in the pore spaces of real soils.

This thesis illuminates the pore-scale processes governing silver nanoparticle transport through soil. In addition, it examines the influence of surface chemistry and grain/pore distributions on those processes. For the …