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dc.contributor.advisorNavathe, Pooshan
dc.contributor.authorFitzgerald, David
dc.date.available2013-09-24T02:14:21Z
dc.date.copyright2013
dc.identifier.citationFitzgerald, D. (2013). Change in Hearing Conservation and Legislation and Prevention of Permanent Threshold Shift (Thesis, Master of Health Sciences). University of Otago. Retrieved from http://hdl.handle.net/10523/4301en
dc.identifier.urihttp://hdl.handle.net/10523/4301
dc.description.abstractBackground: Between 1985 and 2006 there were improvements in hearing conservation at Nyrstar Hobart Smelter, including engineering controls and the introduction of mandatory hearing protection in noisy areas. In 1996 there was a change to Tasmanian legislation regarding compensation for hearing loss, so that compensation was based on audiometric criteria. Objectives: To examine the effect of changes to hearing conservation programmes and legislation.on the rate of hearing deterioration in employees of Nyrstar Hobart Smelter. Methodology: 1. The audiograms of 224 Employees of the Nyrstar Zinc Smelter were compared between two 10-year time periods (1986-1996 and 1996-2006) to determine if there is a difference in the incidence of NIHL diagnoses. Null hypothesis 1: That there is no difference in the incidence of NIHL diagnoses between the first and second 10 year periods 2. The audiograms were further analysed to determine the incidence of NIHL diagnoses at different plants (Roast/Acid/Wharf, Leach/Purification, Electrolysis, Casting) within the site. Null hypothesis 2 – That there is no difference in the incidence of NIHL diagnoses between the areas of the site Results: Overall 22.6% of smelter workers met the criteria for NIHL in the 10 year period before 1996. 28.5% of workers met the criteria NIHL in the 10 year period post 1996. Therefore there was no significant difference in the rate of NIHL between the two time periods (p=0.4864). The proportion of employees in the Roast and Leach plants meeting the criteria for NIHL actually was higher in the latter time period, but the difference was not statistically significant (p= 0.494, p=0.0983). The proportion of employees diagnosed with NIHL showed a mild improvement in the Casting and Electrolysis plants and other miscellaneous staff, but again was not statistically significant (p=0.89, p=0.09, p=0.99). No part of the plant showed a significant difference in the proportion of employees diagnosed with NIHL compared with the population as a whole. Discussion: Noise Induced Hearing Loss is a major cause of occupational morbidity. This study found no significant difference in the frequency of diagnosis of NIHL between two subsequent decades. This suggests no significant impact of two known significant changes over the period - a combination of improved hearing conservation programmes at the worksite and changes to legislation on noise-induced hearing loss.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectNIHL
dc.subjectlegislation
dc.subjecthearing
dc.titleChange in Hearing Conservation and Legislation and Prevention of Permanent Threshold Shift
dc.typeThesis
dc.date.updated2013-09-24T01:24:28Z
dc.language.rfc3066en
thesis.degree.disciplineOccupational Medicine
thesis.degree.nameMaster of Health Sciences
thesis.degree.grantorUniversity of Otago
thesis.degree.levelMasters
otago.openaccessOpen
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