Scott Mundle

Scott Mundle
University of Windsor · Great Lakes Institute for Environmental Research

PhD

About

58
Publications
7,549
Reads
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665
Citations
Citations since 2017
28 Research Items
436 Citations
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
Additional affiliations
May 2010 - May 2014
University of Toronto
Position
  • PostDoc Position

Publications

Publications (58)
Article
Methods to collect and analyze concentration-depth profiles of dissolved methane (C1), ethane (C2), and propane (C3) and their δ¹³C-values from directional drilling operations were evaluated. The δ¹³C values of C1-C3 gases from drill cuttings were consistent; however, deeper zones (>1200 m BG) were subject to greater variability. The variability fo...
Article
Water quality impacts to the Laurentian Great Lakes create bi-national issues that have been subject of investigation since the 1970s. However, distinguishing upgradient sources of nutrients, metals and legacy contaminants in rivers remains a challenge, as they are derived from multiple sources and flows typically vary throughout the region. These...
Article
We used presence and absence data of sentinel invertebrates (stonefly, order Plecoptera) collected by citizen scientists over 17 years to approximate trends in stream health in urban Detroit, Michigan, USA. Citizen science data is commonly collected based on availability of limited funds, thus survey locations lack consistent data collection and mi...
Article
High-frequency acquisition of nutrient concentrations in rivers is needed to generate nutrient loading estimates commensurate with flow and discharge data. Although the combination of field sampling and laboratory analysis is the standard approach to riverine water quality analysis, this strategy is expensive and can miss important storm-related ev...
Article
CO2 co-injection can be used to lower the energy requirements for heavy oil recovery in thermal oil operations. Technologies, including steam-assisted gravity drainage (SAGD) for the extraction of bitumen from oil sands, have the potential to improve the energy efficiency and economics of heavy oil production as well as provide an opportunity for c...
Article
Improved understanding of catchment‐scale hydrology and nutrient transport in agricultural catchments is needed. Here, the annual young water fraction is determined for three southern Ontario headwater catchments using the stable water isotope δ18O; the dominant event contributions for three streams were also determined using a two‐component isotop...
Article
The tributaries flowing through Leamington, Ontario are unique in the Canadian Lake Erie watershed due to the broad spatial extent of greenhouse operations, which more than doubled in size and density from 2011 to 2022. These greenhouse operations are considered to be potential nutrient point sources with respect to observed nutrient concentrations...
Article
Full-text available
Efforts to make research environments more inclusive and diverse are beneficial for the next generation of Great Lakes researchers. The global COVID-19 pandemic introduced circumstances that forced graduate programs and academic institutions to re-evaluate and promptly pivot research traditions, such as weekly seminar series, which are critical tra...
Article
The transport of helium from the crystalline continental basement and overlying Phanerozoic sedimentary formations to the near surface can be controlled by both diffusive and advective processes. The relative role of each is vital to helium resource prediction, and important in quantifying the residence times of fluids relevant to groundwater resou...
Article
Full-text available
The Rio Tinto aluminum smelter at the terminus of the Kitimat River near the town of Kitimat in north coastal British Columbia has been in operation for over 60 years. Following a major upgrade to the facility (~ $6 billion), atmospheric emissions of sulfur dioxide (SO2) from the smelter increased from ~ 6200 tonnes SO2/year in 2008–2013 to ~ 10,50...
Article
Cyanobacterial blooms and the associated hepatotoxins produced (e.g., microcystins, MCs) create a significant human health risk in freshwater lakes around the world, including Lake Erie. Though various physical and chemical treatment options are utilized, these are costly and their effectiveness decreases when other organics are present. Laboratory...
Article
Full-text available
Anthropogenic atmospheric emission and subsequent deposition of sulfur (S) has been linked to disrupted watershed biogeochemical processes through soil and surface water acidification. We investigated watershed-scale impacts of acidic deposition on tributary concentrations and watershed exports of major nutrients and ions for the Kitimat River Wate...
Chapter
Water quality issues that lead to freshwater eutrophication are a rapidly intensifying global concern, and the recent increase in eutrophic conditions in the Great Lakes has gained international attention. The Great Lakes account for over 85% of North America’s freshwater supply and have had a history of water quality problems that peaked in the ea...
Article
A comparative bench-scale and field site analysis of BioCord was conducted to investigate seasonal microbial community dynamics and its impact on nitrogen removal in wastewater. This was assessed using metabolite (NO3−) stable isotope analysis, high-throughput sequencing of the 16S rRNA gene, and RT-qPCR of key genes in biological treatment represe...
Article
Eutrophication of freshwaters is already a problem in many regions globally and will probably worsen as human populations grow and consume more resources. The ability of researchers and governments to anticipate, mitigate, and restore eutrophic freshwaters in a cohesive, integrated manner suffers from key uncertainties in our understanding of the w...
Article
Full-text available
Abstract Eukarya have been discovered in the deep subsurface at several locations in South Africa, but how organisms reach the subsurface remains unknown. We studied river-subsurface fissure water systems and identified Eukarya from a river that are genetically identical for 18S rDNA. To further confirm that these are identical species one metazoan...
Article
Stable (13 C) and radiogenic (14 C) carbon isotope tracers are recognized approaches to identify gas sources using soil gas monitoring techniques; however, definitive characterization from a subsurface injection/storage reservoir can be complicated by processes that produce and consume CO 2. Few studies assess the combined use of compositional (fix...
Article
Stable isotope compositions of methane (δ¹³C and δD) and of short-chain alkanes are commonly used to trace the origin and fate of carbon in the continental crust. In continental sedimentary systems, methane is typically produced through thermogenic cracking of organic matter and/or through microbial methanogenesis. However, secondary processes such...
Article
Eutrophication of freshwater ecosystems and harmful algal blooms (HABs) are an ongoing concern affecting water quality in the Great Lakes watershed of North America. Despite binational management efforts, Lake Erie has been at the center of dissolved reactive phosphate driven eutrophication research due to its repeated cycles of algae blooms. We in...
Article
Full-text available
Greenhouse production of vegetables is a growing global trade. While greenhouses are typically captured under regulations aimed at farmland, they may also function as a point source of effluent. In this study, the cumulative impacts greenhouse effluents have on riverine macronutrient and trace metal concentrations were examined. Water samples were...
Article
Compound specific isotope analysis (CSIA) is widely used to monitor contaminant remediation in groundwater. CSIA-based approaches that use enrichment (ε) values to assess degradative processes rely on the assumption that the contaminant being investigated will have an ε value that is constant and specific to a catalytic pathway of a microorganism....
Chapter
Full-text available
Isotope ratio mass spectrometry (IRMS) provides accurate measurements of relative abundance of isotopes of heavy atoms for reactions that are subject to kinetic isotope effects (KIEs). The recent development of compound-specific isotope analysis (CSIA) allows the use of multiple time points that provide data for a rate plot as well as isotope ratio...
Article
Full-text available
Natural gas extraction from unconventional shale gas reservoirs is the subject of considerable public debate, with a key concern being the impact of leaking fugitive natural gases on shallow potable groundwater resources. Baseline data regarding the distribution, fate, and transport of these gases and their isotopes through natural formations prior...
Article
Baseline characterization of concentrations and isotopic values of dissolved natural gases is needed to identify contamination caused by the leakage of fugitive gases from oil and gas activities. Methods to collect and analyze baseline concentration-depth profiles of dissolved CH4 and C2 H6 and δ(13) C-CH4 in shales and Quaternary clayey tills were...
Article
Baseline characteristics of dissolved methane (CH4) and ethane (C2H6) and their stable isotopes in thick, low hydraulic conductivity, Cretaceous shales were determined using high-resolution core profiling at four sites in the Williston Basin (WB), Canada. Positive correlations with the conservative natural tracer Cl- reflected a lack of measureable...
Article
Full-text available
Following the discovery of the first Eukarya in the deep subsurface, intense interest has developed to understand the diversity of eukaryotes living in these extreme environments. We identified that Platyhelminthes, Rotifera, Annelida and Arthropoda are thriving at 1.4km depths in palaeometeoric fissure water up to 12,300yr old in South African min...
Data
Supplementary Figures 1-8, Supplementary Tables 1-6, Supplementary Notes 1-6 and Supplementary References
Data
Star Diamond Mine at -640 meter. Using the endoscope the recording starts at the end of the >1 meter long metal tube casing and shows the end of the borehole casing into a small rock chamber covered with filamentous biofilm. For reference the borehole diameter is 4.5 cm in diameter. The white out of focus covering of the tube itself is biofilm. The...
Data
Star Diamond + 'vacuum cleaner' at -640 meter. The footage shows use of the 'vacuum cleaner' to suck up biofilm from the same borehole/chamber as in SVIDEO 2. The footage concentrates on sampling in the chamber where biofilm grows attached to the rock face. Most of the biofilm is gone due to closing of the borehole in previous to making the footage...
Data
Kopanang gold mine borehole at -1,4 km. The Kopanang gold mine borehole shows thick swats of white biofilm growing on the bottom of the borehole in the area covered by fissure water. Yellow, more solid appearing biofilm covered the left wall, an area probably submerged during attachment of the trapping filter as this slowed the flow of the borehole...
Data
Finsch Diamond mine horizontal borehole at -880 meter. The horizontal Finsch diamond mine borehole contains walls well covered in a different kind of biofilm in comparison with SVideo 1 and 2 and is situated approximately 8 meters inside the borehole past the metal casing. The biofilm on the rock face looks crusty and moves less in the current unle...
Data
Time lapse recording of a 9 cm petri dish containing Kopanang biofilm with bacteria and A. hemprichi sp. Recording was one frame/minute for 24 h using a GoPro camera. Almost immediately the redistribution and clumping is evident until the pieces of biofilm become too large to be moved.
Data
Time lapse recording of 9 cm petri dish containing Kopanang biofilm with bacteria and Nematoda. Recording was one frame/minute for 24 hours using a GoPro camera. Except for the slow settling of the biofilm which is faintly visible in the center of the Petri dish no other effects are visible.
Data
Time lapse recording of a side piece of a 9 cm Petri dish containing Kopanang biofilm with bacteria and A. hemprichi. Recording was one frame/minute for 24 h using a Sony mounted camera on an Olympus stereomicroscope linked to a DELL computer recording via the freeware software Splitcam. Unlike previous reports the clustering occurs by the movement...
Conference Paper
Full-text available
Fluids discharging from fractures over 2.8 km deep in a South African mine have been isolated from the crust for up to 25 Myr and sustain microbial communities of H 2-utilizing methanogens and sulphate reducers [1,2]. Recently, noble gas-derived residence times of more than a billion years were determined for a series of saline fracture fluids from...
Article
Compound Specific Isotope Analysis (CSIA) is widely utilized to study the fate of organic contaminants in groundwater. To date, however, no method is available to obtain CSIA samples at a fine (cm) spatial scale across the sediment - surface water interface (SWI), a key boundary for discharge of contaminated groundwater to surface water. Dissolved...
Article
Chlorinated benzenes are ubiquitous organic contaminants found in groundwater and soils. Compound specific isotope analysis (CSIA) has been increasingly used to assess natural attenuation of chlorinated contaminants, in which anaerobic reductive dechlorination plays an essential role. In this work, carbon isotope fractionation of the three dichloro...
Chapter
The mechanisms of decarboxylation reactions are normally considered in terms of steps leading to dissociative processes that cleave a C-C bond and release CO2. Observations of specific acid-catalyzed decarboxylation reactions, such as those of pyrrole-carboxylic acids, are inconsistent with such a mechanism. Formulation of mechanisms involving rele...
Article
Kinetic evidence suggests that acid-catalyzed decarboxylation reactions of aromatic carboxylic acids can occur by a hydrolytic process that generates protonated carbonic acid (PCA) as the precursor of CO2. Measurements of reaction rates and carbon kinetic isotope effects (CKIE) for decarboxylation of isomeric sets of heterocyclic carboxylic acids i...
Article
Processes that lead to pressure changes in closed experimental systems can dramatically increase the total uncertainty in enrichment factors (ε) based on headspace analysis and compound-specific isotope analysis (CSIA). We report: (1) A new technique to determine ε values for non-isobaric processes, and (2) a general approach to evaluate the experi...
Article
Compound specific isotope analysis (CSIA) has been applied to monitor bioremediation of groundwater contaminants and provide insight into mechanisms of transformation of chlorinated ethanes. To date there is little information on its applicability for chlorinated methanes. Moreover, published enrichment factors (ε) observed during the biotic and ab...
Article
Elucidation of the mechanism for decarboxylation of indolecarboxylic acids over a wide range of solution acidity reveals the importance of protonated carbonic acid (PCA) as a reaction intermediate. In concentrated acid, the initial addition of water to the carboxyl group of the indolecarboxylic acid leads to a hydrated species that is capable of re...
Article
Full-text available
Chlorinated ethenes are commonly found in contaminated groundwater. Remediation strategies focus on transformation processes that will ultimately lead to nontoxic products. A major concern with these strategies is the possibility of incomplete dechlorination and accumulation of toxic daughter products (cis-1,2-dichloroethene (cDCE), vinyl chloride...
Article
Brønsted plots for general-base-catalyzed enolization of aldehydes and ketones show significant negative deviations for the rates of proton removal by sterically hindered amine bases. The origins of the deviations are not apparent from considerations of interactions at the site of the proton transfer. Contrasting behavior is observed in general-bas...
Article
An upper-level mechanistic organic experiment is outlined where undergraduates measure kinetic rate constants for decarboxylation of pyrrole-2-carboxylic acid by the initial-rates method. UV spectroscopy is used to monitor reactant disappearance in both hydrochloric acid and deuterium chloride at different temperatures. Individual data are pooled a...
Article
While compound specific isotope analysis (CSIA) has been used extensively to investigate remediation of chlorinated ethenes, to date considerably less information is available on its applicability to chlorinated ethanes. In this study, biodegradation of 1,1,1-trichloroethane (1,1,1-TCA) and 1,1-dichloroethane (1,1-DCA) was carried out by a Dehaloba...
Article
Full-text available
Acid-catalyzed decarboxylation reactions of carboxylic acids should avoid formation of protonated carbon dioxide, a very high energy species. A potential alternative route parallels ester hydrolysis, with addition of water to the carboxyl group followed by protonation of the unsaturated leaving group and formation of protonated carbonic acid, a spe...
Article
It has been proposed that the decarboxylation of mandelylthiamin, the adduct of benzoylformate and thiamin, is uniquely catalyzed by protonated pyridines through a preassociation mechanism in which proton transfer competes with the internal return of carbon dioxide. Application of this mechanism suggests that the observed primary (12)C/(13)C kineti...
Article
The decarboxylation of pyrrole-2-carboxylic acid is subject to acid catalysis in strongly acidic solutions. Protonation of the pyrrole ring at C2 produces a potentially low-energy carbanion leaving group. Carbon dioxide formation is suppressed by the requisite formation of its high-energy conjugate acid. As a result, decarboxylation must proceed vi...
Article
An organic class project is described where upper-level undergraduates measure kinetic rate constants for semicarbazone formation, by reacting semicarbazide with a meta- or para-substituted benzaldehyde. UV-vis spectroscopy is used to follow product formation. Individual results are compiled to yield a class data set, which is used to construct a l...

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