Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 63-65). Also available via the Internet.

Thesis (PhD) - Faculty of Life and Social Sciences, Swinburne University of Technology, 2009. / Submitted in full requirement for the degree of Doctor of Philosophy, Faculty of Life and Social Sciences, Swinburne University of Technology - 2009. Typescript. Includes bibliographical references (p. 137-160)

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

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A range of ion selective electrodes (ISEs) for the determination of nitrate has been produced using polymeric membranes containing immobilised quaternary ammonium salts as the ion exchanger. The use of the conventional solvent casting technique gave rise to a relatively low cross-link density, two sided response and poor thickness control. The development of a hot pressing technique resolved all the se problems and would readily suit large scale manufacturing. In this work poly(acrylonitrilebutadiene)(NBr) was selected as the membrane matrix and was robust, gave enhanced selectivity coefficients and extended membrane lifetime. The best electrode fabricated contained 6-5% m/m triallyloctylammonium bromide, 7-2% m/m dicumyl peroxide and 39-7% m/m2 -nitrophenyloctyl ether in a 50% ACN content N Br polymer matrix. The electrode had a lifetime in excess of 665 days and the response to nitrate was Nernstian in the range I x 10" to I x 10' mol dm-1 of nitrate. The limit of detection was 4-5 x IW mol dm-1 and the selectivity coefficient k Pot NO,,- - C1 was 5.3 xIW. The immobilised ion exchanger membrane electrode offered superior lifetime and mechanical strength. The cross-link density of the membranes was determined by solvent swelling and the use of the Flory-Rehner equation. The role of cross-link density upon the electroanalytical properties of membranes was investigated in the range 0-6 x 10' to 11-0 x 10' mol cross-link cm-'. The membranes were studied using electron microscopy and the conditioning process monitored using ion exchange chromatography. Two different response mechanisms were proposed dependent on the membrane composition and the inclusion of solvent mediator.

Jagals, P., Prof. du Preez, H.H., Prof.

Water quality evaluation is a global concern due to its effect on public health. Different procedures can be implemented to evaluate specific standards of water quality. DNA extraction to characterize the microbial community in the water distribution systems is important. To optimize the DNA extraction process the effect of residual chlorine and water composition was tested. The results exposed the limited effect of the samples dechlorination. Total cell number effect can be varied according to water quality. Also, the study indicated the possible inhibitory effect of the rust on the DNA extraction from drinking water samples.

The purpose of this study is to evaluate the drinking water quality of Kaohsiung city and its cancer risk potential to residents using city water. In this study, water qualities from different locations and seasons were collected and compared with drinking water quality standards. Total trihalomethanes (TTHM), which is the byproduct of disinfection process, has become one of the major concerns due to its high cancer risk potential. TTHM is composed of trichloromethane (TCM), dichlorbromomethane (BDCM), dibromochloromethane (DBCM), and tribromo methane (TBM), and the drinking water standard for TTHM is 0.1 mg/L. Effective on July 1, 2006, this standard will be revised to 0.08 mg/L, which is adopted from U.S. EPA. In this study, tap water quality data were provided from the technical office of Environmental protection Bureau, Kaohsiung City. These data were collected quarterly in 2004 and 2005 from 50 locations in the city water net system. Moreover, health and risk assessment models developed by US Environmental Protection Agency (EPA) were used for cancer risk calculation. Results from the water quality evaluation indicate that drinking water quality meets with the standards regulated by government. Except for TTHM, results show that sampling locations and seasons did not have significant influence on the variations in other water quality parameters. Results of health and risk assessment of TTHM show that inhalation is the major route of risk exposure, which contributes 80.84% of the cancer risk. The dermal contact only contributes about 0.36% of the cancer risk. Among those four components of TTHM, TCM had higher detected concentrations. However, the major cancer risk came from BDCM and DBCM. Results reveal that the Chijin District (located at the end pipe area) of Kaohsiung city had the highest TTHM cancer risk (3.82¡Ñ10-4), whereas Sanmin District (located at the front pipe area) got the lowest risk (4.10¡Ñ10-5). The averaged TTHM health risk for the general public in Kaohsiung is about 1.50¡Ñ10-4. This calculated risk is much higher than the acceptable risk value (¡Ø10-6) recommended by US EPA. Thus, more stringent standards and more effective treatment technologies should be adopted by related authorities.