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- All Subjects: Environmental health
- All Subjects: Nanoparticles
Description
Nanotechnology is a scientific field that has recently expanded due to its applications in pharmaceutical and personal care products, industry and agriculture. As result of this unprecedented growth, nanoparticles (NPs) have become a significant environmental contaminant, with potential to impact various forms of life in environment. Metal nanoparticles (mNPs) exhibit unique properties such as increased chemical reactivity due to high specific surface area to volume ratios. Bacteria play a major role in many natural and engineered biogeochemical reactions in wastewater treatment plants and other environmental compartments. I have evaluated the laboratory isolates of E. coli, Bacillus, Alcaligenes, Pseudomonas; wastewater isolates of E. coli and Bacillus; and pathogenic isolate of E. coli for their response to 50 & 100 nm sized Cu nanoparticles (CuNPs). Bactericidal tests, scanning electron microscopy (SEM) analyses, and probable toxicity pathways assays were performed. The results indicate that under continuous mixing conditions, CuNPs are effective in inactivation of the selected bacterial isolates. In general, exposure to CuNPs resulted in 4 to >6 log reduction in bacterial population within 2 hours. Based on the GR, LDH and MTT assays, bacterial cells showed different toxicity elicitation pathways after exposure to CuNPs. Therefore, it can be concluded that the laboratory isolates are good candidates for predicting the behavior of environmental isolates exposed to CuNPs. Also, high inactivation values recorded in this study suggest that the presence of CuNPs in different environmental compartments may have an impact on pollutants attenuation and wastewater biological treatment processes. These results point towards the need for an in depth investigation of the impact of NPs on the biological processes; and long-term effect of high load of NPs on the stability of aquatic and terrestrial ecologies.
ContributorsAlboloushi, Ali (Author) / Abbaszadegan, Morteza (Thesis advisor) / Alum, Absar (Committee member) / Fox, Peter (Committee member) / Olson, Larry (Committee member) / Arizona State University (Publisher)
Created2012
Description
United States Environmental Protection Agency (USEPA) had identified and recommended air quality monitoring to take place at 63 schools throughout the country. Unfortunately, tribal schools were not considered during the time USEPA conducted the analysis. The importance of identifying any air toxic pollutants affecting school children needs to be analyzed. Conducting an air monitoring toxic analysis on the Navajo Nation at Church Rock Elementary School, Church Rock, New Mexico (CRNM) was carried out. The current school location posed a concern, in regards to the surrounding stationary, mobile, and natural emissions emitted all types of toxic pollutants. USEPA sponsors various air monitoring program, which Tribal Air Monitoring Support (TAMS) program undertook, and offered tribal programs, organizations or agencies to utilized air monitoring equipment's. The air monitoring setup was conducted with the contract Eastern Research Group, Inc. (ERG) laboratory, where collection of 24-hour ambient air samples for 60 days on a 6-day sampling interval were performed. The analysis for volatile organic compounds (VOCs)were collected from canister samples using USEPA Compendium Method TO-15, polycyclic aromatic hydrocarbons (PAHs) from polyurethane foam (PUF) and XAD-2 resin samples using USEPA Compendium Method TO-13A. Carbonyl compounds were collected by sorbent cartridge samples using USEPA Compendium Method TO-11A, and trace of metals from filters were sampled using USEPA Compendium Method IO-3.5 and FEM EQL-0512-202. A total of 53 VOC concentrations were greater than 1 μg/m3, where dichlorodifluoromethane, trichlorofluoromethane, chloromethane, dichloromethane, propylene, toluene, acrolein and acetylene were detected. A total of 23 carbonyl compound concentrations were greater than 1 μg/m3, where acetone and formaldehyde were measured. Naphthalene average with the highest average for PAHs, where phenanthrene and retene were the second and third highest averages. As for the metals the highest averages resulted from manganese, chromium and lead. Overall, the air toxic pollutants resulted from CRNM surrounding monitoring site were detected. Identifying the potential emitter source or sources cannot be assessed.
ContributorsBilley, Karmen (Author) / Olson, Larry (Thesis advisor) / Peterson, Danny (Committee member) / Brown, Albert (Committee member) / Arizona State University (Publisher)
Created2015