In the semiconductor industry, numerous potential occupational exposures exist as a result of the diversity of chemical and physical hazards unique to integrated circuit manufacturing. The hazards associated with maintenance tasks are challenging because the sporadic nature of the tasks make exposure monitoring difficult. In particular, vacuum pump maintenance is hazardous due to the close contact with chemical waste by-products. The purpose of this study was to characterize the chemical and physical occupational exposures associated with vacuum pump maintenance (VPM) in a semiconductor manufacturing environment. The study population consisted of 9 VPM technicians at a semiconductor manufacturing plant in Oregon. VPM tasks were observed and prioritized according to potential risk of exposure. For each task studied, an exposure monitoring strategy was developed to quantify both chemical and noise exposures. Personal and area air samples of potential waste gases were conducted during maintenance tasks. All air samples were below established governmental standards. Detectable levels were found for three tasks: 0.040 milligrams per cubic meter (mg/m��) of hydrochloric acid, 0.014 mg/m�� of chlorine, and 0.08 mg/m�� of fluoride containing gases during tasks associated with the metal etch tool, polynitride etch tool, and tungsten deposition tool, respectively. Several bulk samples of waste residues collected during the tasks where corrosive having low pH levels. Representative noise sampling was conducted during a 12 hour shift to characterize noise exposures. Noise samples revealed that 43% of the samples were above the 80 dBA action limit thus requiring the VPM technicians to be involved in a hearing conservation program. Field observations revealed that there were many chemical hazards associated with waste gases and residues, therefore it is likely that occupational exposures occur even though they were not detected at significant levels in this study. In addition, there were several ergonomic risk factors associated with dismantling the pump during the maintenance activities. Specific improvements in personal protective equipment, general work practices, ergonomics, and engineering controls will help to reduce the potential for occupational exposures unique to VPM. Results from this study indicate the need to conduct in depth hazard evaluations of high risk populations such as the VPM technicians. / Graduation date: 1997

Unknown questions remain concerning the health of migrant farm workers, seasonal farm workers, and other rural poor people. The objectives of this study were to determine the demographic profile of a sample from a Community and Migrant Health Center; to determine the prevalence of disease in migrant farm workers, seasonal farm workers and other clients; and to determine if differences existed in the prevalence of disease between the three occupational groups. Information from medical records for clients who visited an Oregon Community and Migrant Health Center during 1993 was abstracted to determine whether differences existed in demographic characteristics and in health status between migrant farm workers, seasonal farm workers, and other clients. A random sample of 600 medical charts was selected from the three occupational groups stratified by sex. The sample included adults and children classified as migrant or seasonal farm workers and other clients. Data abstracted from charts included socio-demographic information, physiologic measurements, biochemical testing results, and disease prevalence. Clients in this sample represented Latino (85.17%), Russian (4.8%), and Anglo (10%) cultures. Female clients who were not migrant or seasonal farm workers had a mean age of 27.42 years which was significantly different from the mean age of female migrant farm workers of 18.95 years, and of female seasonal farm workers of 20.35 years. Females who were not migrant or seasonal farm workers had significantly higher mean body mass indexes, and systolic and diastolic blood pressures. Female children classified as migrant farm worker had significantly higher blood lead levels than female children whose parents were not migrant or seasonal farm workers. Glucose levels for migrant farm workers was significantly higher than either of the other two occupational groups. Findings of the study indicated that common diagnoses included upper respiratory infection, otitis media, intestinal parasites or pathogens, dermatitis, and urinary tract infection. The most commonly reported injuries were due to lacerations and motor vehicle accidents. Additionally, 31.57% of PAP tests were abnormal, and violence against girls and women was reported. Diagnoses of chronic diseases included diabetes, hypertension, AIDS, cancer, and heart disease. / Graduation date: 1996

<p>Physical inactivity together with overweight and obesity has emerged as a major health risk factor for chronic disease of lifestyle as coronary heart disease, diabetes type 2, and hypertension affecting adolescents with physical disabilities in developed countries. This has contributed to the increase of social and economic costs of healthcare and social services in these countries. Review of literature has revealed that little has been documented about the status of adolescents with physical disabilities in developing countries. This study, therefore, aimed at establishing the degree of physical inactivity among high school adolescents with physical disabilities in Kenya.</p>

Excessive nitrates in drinking water pose a human health threat, especially to infants. Methemoglobinemia, or blue-baby syndrome, is a potentially fatal condition that inhibits the ability of red blood cells to bind and transport oxygen. Nitrates/nitrites have also been linked to such conditions as cancer, birth defects, and behavioral and developmental abnormalities. Nitrates are frequently found in wells in rural farming areas because synthetic fertilizers (containing nitrates) leach from the soil into the groundwater. The Lower Umatilla Basin (LUB) in Morrow and Umatilla counties of Oregon represents an intensively farmed and irrigated area in which relatively high amounts of nitrates are present in the groundwater and domestic well water. This study investigated population demographics for the rural Lower Umatilla Basin, comparing these data to identified well-water nitrate levels for the purpose of estimating nitrate exposures and potential risk of adverse health effects in the survey area. Results of the investigation revealed that 25 percent of the domestic-use wells in the survey area had nitrate levels that were in excess of the 10 ppm nN MCL for drinking water, as established by the U.S. Environmental Protection Agency. From access to these wells, 23 percent of the surveyed population was exposed to nitrate concentrations in excess of the MCL standard. However, resident infants were neither exposed to well-water nitrates in excess of the standard, nor were they exposed to illness that could have increased the risk of methemoglobinemia. The LUB survey population was generally older than the populations from cities in the LUB or the combined populations of rural areas of Morrow and Umatilla counties. The population included few women of childbearing age, and it was not subject to an appreciable increase in the proportion of younger to older families. These factors reduced the likelihood of a significant increase in the infant population, which also minimized the risk of methemoglobinemia to this population. Even though the risk of methemoglobinemia to infants was low in the LUB area, it is recommended that exposures to well-water nitrates be prevented, if possible even for adults, to reduce the potential for chronic, adverse health effects from excess nitrate ingestion. Continued monitoring of private wells by state agencies is recommended, with attention directed at domesticuse wells with nitrate levels in excess of 10 ppm nN. This information should be shared with local health departments for follow-up, investigation, and educational efforts as needed. Future studies by the Oregon DEQ, or other agencies which seek to document the sources of well-water nitrate contamination in the LUB, should include an investigation of the influence of local sources of nitrate contamination. / Graduation date: 1993

University of Macau / Faculty of Social Sciences and Humanities / Department of Psychology

published_or_final_version / Community Medicine / Master / Master of Public Health

published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / Public Health / Master / Master of Public Health