Matching Items (5)
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- All Subjects: Analytical Chemistry
- Genre: Academic theses
- Creators: Halden, Rolf U.
Description
Monitoring human exposure to chemicals posing public health threats is critically important for risk management and for informing regulatory actions. Chemical threats result from both environmental pollutants and elected substance use (e.g., consumption of drugs, alcohol and tobacco). Measuring chemical occurrence and concentrations in environmental matrices can help to pinpoint human exposure routes. For instance, indoor dust, a sink of indoor environmental contaminants, can serve to assess indoor air contamination and associated human exposures. Urban wastewater arriving at treatment plants contains urine and stool from the general population, the analysis of which can provide information on chemical threats in the community and ongoing harmful exposures. Analysis of sewage sludge can serve to reveal the identity and quantity of persistent organic pollutants in cities and inform estimates of toxic body burdens in local populations.
The objective of this dissertation was to investigate the occurrence and quantity of select, potentially harmful, anthropogenic chemicals in various environmental matrices and to explore the diagnostic value of analytical assays for informing public health decision-making. This dissertation (i) is the first to report spatio-temporal variations and estrogenic burdens of five parabens in sewage sludge from at the U.S. nationwide scale; (ii) represents the first China-wide survey to assess the occurrence and toxic emissions of parabens, triclosan, triclocarban, as well as triclocarban metabolites and transformation products contained in Chinese sewage sludge; (iii) documents the first use of a dispersive solid phase extraction method for indoor dust to measure dust-borne parabens, triclosan and triclocarban and estimating associated human exposures from dust ingestion; and (iv) is the first U.S. study to assess population-level alcohol and nicotine consumption in three U.S. communities using wastewater-based epidemiology (WBE). Obtained data on baseline levels of selected emerging contaminants in sewage sludge and indoor dust can serve to inform the future monitoring needs, risk assessment, and policy making. This work showcases the utility of WBE and urban metabolism metrology via dust and sewage sludge analysis to assess human behavior (e.g., drinking and smoking) and exposure risks more rapidly, efficiently and anonymously than traditional approaches can.
The objective of this dissertation was to investigate the occurrence and quantity of select, potentially harmful, anthropogenic chemicals in various environmental matrices and to explore the diagnostic value of analytical assays for informing public health decision-making. This dissertation (i) is the first to report spatio-temporal variations and estrogenic burdens of five parabens in sewage sludge from at the U.S. nationwide scale; (ii) represents the first China-wide survey to assess the occurrence and toxic emissions of parabens, triclosan, triclocarban, as well as triclocarban metabolites and transformation products contained in Chinese sewage sludge; (iii) documents the first use of a dispersive solid phase extraction method for indoor dust to measure dust-borne parabens, triclosan and triclocarban and estimating associated human exposures from dust ingestion; and (iv) is the first U.S. study to assess population-level alcohol and nicotine consumption in three U.S. communities using wastewater-based epidemiology (WBE). Obtained data on baseline levels of selected emerging contaminants in sewage sludge and indoor dust can serve to inform the future monitoring needs, risk assessment, and policy making. This work showcases the utility of WBE and urban metabolism metrology via dust and sewage sludge analysis to assess human behavior (e.g., drinking and smoking) and exposure risks more rapidly, efficiently and anonymously than traditional approaches can.
ContributorsChen, Jing (Author) / Halden, Rolf U. (Thesis advisor) / Borges, Chad R (Committee member) / Abbaszadegan, Morteza (Committee member) / Arizona State University (Publisher)
Created2018
Description
Volcanic devolatilization is one of the major processes in the global nitrogen cycle. Past studies have often estimated the magnitude of this flux using volcanic emission measurements, which are limited to currently active systems and sensitive to atmospheric contamination. A different methodological approach requires appropriate analytical parameters for nitrogen analysis in silicate glasses by secondary ion mass spectrometry (SIMS), which have not yet been established. To this end, we analyze various ion implanted basaltic and rhyolitic glasses by SIMS. We demonstrate that water content significantly affects the ion yields of 14N+ and 14N16O−, as well as the background intensity of 14N+ and 12C+. Application of implant-derived calibrations to natural samples provide the first reported concentrations of nitrogen in melt inclusions. These measurements are from samples from the Bishop Tuff in California, the Huckleberry Ridge Tuff of the Yellowstone Volcanic Center, and material from the Okaia and Oruanui eruptions in the Taupo Volcanic Center. In all studied material, we find maximum nitrogen contents of less than 45 ppm and that nitrogen concentration varies positively with CO2 concentration, which is interpreted to reflect partial degassing trend. Using the maximum measured nitrogen contents for each eruption, we find that the Bishop released >3.6 x 1013 g of nitrogen, the Huckleberry Ridge released >1.3 x 1014 g, the Okaia released >1.1 x 1011 g of nitrogen, the Oruanui released >4.7 x 1013 g of nitrogen. Simple calculations suggest that with concentrations such as these, rhyolitic eruptions may ephemerally increase the nitrogen flux to the atmosphere, but are insignificant compared to the 4 x 1021 g of nitrogen stored in the atmosphere.
ContributorsRegier, Margo Elaine (Author) / Hervig, Richard L (Thesis advisor) / Roggensack, Kurt (Committee member) / Till, Christy B. (Committee member) / Arizona State University (Publisher)
Created2016
Description
This dissertation focused on the development and application of state-of-the-art monitoring tools and analysis methods for tracking the fate of trace level contaminants in the natural and built water environments, using fipronil as a model; fipronil and its primary degradates (known collectively as fiproles) are among a group of trace level emerging environmental contaminants that are extremely potent arthropodic neurotoxins. The work further aimed to fill in data gaps regarding the presence and fate of fipronil in engineered water systems, specifically in a wastewater treatment plant (WWTP), and in an engineered wetland. A review of manual and automated “active” water sampling technologies motivated the development of two new automated samplers capable of in situ biphasic extraction of water samples across the bulk water/sediment interface of surface water systems. Combined with an optimized method for the quantification of fiproles, the newly developed In Situ Sampler for Biphasic water monitoring (IS2B) was deployed along with conventional automated water samplers, to study the fate and occurrence of fiproles in engineered water environments; continuous sampling over two days and subsequent analysis yielded average total fiprole concentrations in wetland surface water (9.9 ± 4.6 to 18.1 ± 4.6 ng/L) and wetland sediment pore water (9.1 ± 3.0 to 12.6 ± 2.1 ng/L). A mass balance of the WWTP located immediately upstream demonstrated unattenuated breakthrough of total fiproles through the WWTP with 25 ± 3 % of fipronil conversion to degradates, and only limited removal of total fiproles in the wetland (47 ± 13%). Extrapolation of local emissions (5–7 g/d) suggests nationwide annual fiprole loadings from WWTPs to U.S. surface waters on the order of about one half to three quarters of a metric tonne. The qualitative and quantitative data collected in this work have regulatory implications, and the sampling tools and analysis strategies described in this thesis have broad applicability in the assessment of risks posed by trace level environmental contaminants.
ContributorsSupowit, Samuel (Author) / Halden, Rolf U. (Thesis advisor) / Westerhoff, Paul (Committee member) / Johnson, Paul C (Committee member) / Arizona State University (Publisher)
Created2015
Description
A novel technique for measuring heavy trace elements in geologic materials with secondary ion mass spectrometry (SIMS) is presented. This technique combines moderate levels of mass resolving power (MRP) with energy filtering in order to remove molecular ion interferences while maintaining enough sensitivity to measure trace elements. The technique was evaluated by measuring a set of heavy chalcophilic elements in two sets of doped glasses similar in composition to rhyolites and basalts, respectively. The normalized count rates of Cu, As, Se, Br, and Te were plotted against concentrations to test that the signal increased linearly with concentration. The signal from any residual molecular ion interferences (e.g. ²⁹Si³⁰Si¹⁶O on ⁷⁵As) represented apparent concentrations ≤ 1 μg/g for most of the chalcophiles in rhyolitic matrices and between 1 and 10 μg/g in basaltic compositions. This technique was then applied to two suites of melt inclusions from the Bandelier Tuff: Ti-rich, primitive and Ti-poor, evolved rhyolitic compositions. The results showed that Ti-rich inclusions contained ~30 μg/g Cu and ~3 μg/g As while the Ti-poor inclusions contained near background Cu and ~6 μg/g As. Additionally, two of the Ti-rich inclusions contained > 5 μg/g of Sb and Te, well above background. Other elements were at or near background. This suggests certain chalcophilic elements may be helpful in unraveling processes relating to diversity of magma sources in large eruptions. Additionally, an unrelated experiment is presented demonstrating changes in the matrix effect on SIMS counts when normalizing against ³⁰Si⁺ versus ²⁸Si²⁺. If one uses doubly charged silicon as a reference, (common when using large-geometry SIMS instruments to study the light elements Li - C) it is important that the standards closely match the major element chemistry of the unknown.
ContributorsCarlson, Eric Norton (Author) / Hervig, Richard L (Thesis advisor) / Roggensack, Kurt (Committee member) / Burt, Donald M (Committee member) / Arizona State University (Publisher)
Created2021
Description
Novel means are needed to diagnose neurodegenerative diseases (NDDs) and cancer, given delays in medical diagnosis and rising rates of disease incidence, prevalence, and mortality worldwide. Development of NDDs and cancer has been linked to environmental toxins. Ensuing epigenetic changes may serve as helpful biomarkers to diagnose amyotrophic lateral sclerosis (ALS), Parkinson’s Disease (PD), and Alzheimer’s Disease (AD) as well as various cancers sooner and more accurately. This dissertation tabulates and evaluates a spectrum of diagnostic matrixes (i.e., soil, sewage sludge, blood) and markers of disease to inform disease surveillance. A literature search using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Bradford Hill criteria implicated BMAA, formaldehyde, Mn, Hg, and Zn as environmental factors with strong association to ALS risk. Another PRISMA search identified epigenetic changes (e.g., DNA methylation) in NDD patients associated with environmental toxic exposures to air pollutants, heavy metals, and organic chemicals. Of the 180 environmental toxins hypothesized to be associated with AD, PD, or ALS, four heavy metals (As, Cd, Mn, and Hg) were common to these NDDs. Sources, as well as evidence and proxies of human exposure to these heavy metals and Pb were investigated here, namely the metal industries, and metal concentrations in topsoil, sewage sludge, and blood. Concentrations of Cd and Pb in sewage sludge were found to be significantly correlated with NDD prevalence rates in co-located populations (state-level) with odds ratios of 2.91 and 4.08, respectively. Markers of exposure and disease in urine and feces were also evaluated using PRISMA, finding 73 of 94 epigenetic biomarker panels to be valid for tracking primarily gastric and urinary cancers. In all studies, geospatial analyses indicated a preference in study cohorts located in the U.S., Europe, and the northern hemisphere, leaving underserved many populous regions particularly in the southern hemisphere. This dissertation draws attention to sewage sludge as a currently underutilized proxy matrix for assessing toxic human exposures and further identified a spectrum of particularly attractive, non-invasive biomarkers for future diagnostic use to promote early detection, survivability, and quality of life of individuals at risk of NDDs and cancer.
ContributorsNewell, Melanie Engstrom (Author) / Halden, Rolf U. (Thesis advisor) / Mastroeni, Diego (Committee member) / Lee, Heewook (Committee member) / Arizona State University (Publisher)
Created2023