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Oral Session 16 – Exposure assessment 2

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M. Whitrow1, D. Pisaniello1, B. Smith1, L. Pilotto2.1University of Adelaide, Adelaide, SA, Australia; 2Flinders University, Adelaide, SA, Australia

Introduction: A case control study was undertaken to evaluate the contributions of occupational and environmental exposures to carcinogens potentially associated with an excess of lung cancer in the industrial northwest region of Adelaide, Australia. This paper describes the methodology and findings of the retrospective exposure assessment.

Methods: Cases and controls were personally interviewed with a highly structured questionnaire entailing a lifetime calendar history of occupation, cigarette smoking, and residence, with additional questions on hobbies, family history, and other factors. A panel of three experienced occupational hygienists was used to individually and collectively rate exposures to lung carcinogens associated with reported industries and jobs. Residential exposure was assessed by geographical information systems, downwind frequency, and estimated emissions from six major local industries. Environmental exposures occurring outside northwest Adelaide were assessed via information on polluting industries located within the suburb of residence.

Results: Of the 142 cases and 415 controls, 70% were male, and cases were significantly more likely to be smokers. Aside from polycyclic aromatic hydrocarbon exposure, the proportion of subjects with occupational carcinogen exposure was relatively low, with more than 50% judged as having no appreciable exposure. Agreement between the three panellists was moderate (κ = 0.4 to 0.6) whereas the agreement between individual ratings and the consensus rating was good (κ = 0.6 to 0.8) across the six specified lung carcinogens. Generally, there was no difference in lung carcinogen exposure between cases and controls. Residential exposure was not significantly related to being a case or control.

Conclusions: This study suggests that smoking, rather than occupational or environmental carcinogen exposures, explains the excess of lung cancer in this community.


A. Carter1, R. Muller1, M. Ridd2, M. Wicking3, T. Magee3.1School of Public Health and Tropical Medicine, James Cook University, Townsville, Qld; 2School of Pharmacy and Molecular Sciences, James Cook University, Townsville, Qld; 3WMC Fertilizers Pty Ltd, Phosphate Hill, Qld

Introduction: In 2001, WMC Fertilizers commissioned the School of Public Health and Tropical Medicine at James Cook University to develop, conduct, and evaluate epidemiological research studies of workplace environment and employee health at the Phosphate Hill fertiliser production plant. The main health issue identified prior to the commencement of the studies related to the potential for exposure to hazardous chemicals. In response to these concerns, environmental sampling and mapping during routine operating conditions and monitoring of employees during non-routine tasks were conducted to quantify the occupational exposure to hydrogen fluoride (HF).

Methods: A large scale environmental sampling of the plant was conducted during routine operating conditions in two successive annual rounds commencing in 2001. Samples were collected on silica gel tubes using air sampling pumps over 6 hours. The sampling points were radially distributed around the suspected sources of HF in 2001, while in 2002 the points were deliberately biased towards the sources identified by the 2001 mapping. HF exposures during non-routine tasks for individual employees were measured via airborne concentrations of HF collected on treated filters using air sampling pumps in combination with excreted fluoride in urine samples obtained between 1 and 2 hours after the task.

Results: HF was detected in 38% (n = 36) of the 2001 and 59% (n = 60) of the 2002 environmental samples. Two samples in 2001 and one sample in 2002 were at or marginally greater than the National Occupational Health and Safety Committee 8 hour Time Weighted Average (2.6 mg/m3). Collection of the HF exposure data for employees during non-routine tasks commenced in January 2004 and the results of the analysis will be presented.

Conclusions: Under routine operating conditions, the ambient levels of HF do not appear to pose a risk to health at the Phosphate Hill site. The results of the personal monitoring of HF will be discussed with reference to changes in workplace procedures and practices.


D. Kielkowski1,2, A. Baker1, K. Channa1, I. Naik1.1National Institute for Occupational Health, NHLS, Johannesburg, South Africa; 2School of Public Health University of the Witwatersrand, Johannesburg, South Africa

Introduction: A survey of ethylene oxide exposure in sterilising units of public hospitals in South Africa was conducted in 2003.

Methods: In each sterilising unit, 5 day measurements of environmental and personal samples were taken. NIOH method number 614 was employed to determine ethylene oxide (EtO) levels, and duplicate samples were sent to US Occupational Safety and Health Administration for validation.

Results: Ten of 22 hospitals used ethylene oxide (EtO). There were 221 environmental samples were collected; of those; 103 at the EtO machines, 61 in the EtO room at the door, and 51 in the general working area. Personnel operating EtO machines during loading and unloading procedure provided 98 samples. Half of the participating hospitals had positive personal samples for EtO; two measurements were above the 1 ppm daily recommended limit, and one above the peak exposure limit of 5 ppm. Machine failure was observed in one of the hospitals, resulting in high environmental levels. One of 51 environmental samples in the general area showed positive, low levels of EtO, suggesting that fugitive emission of EtO to other working areas is unlikely. The machines employed by the hospitals are modern and fully automated, making exposure to EtO minimal if used appropriately. Machine maintenance and good ventilation system is key to lowering EtO exposure in hospitals.

Conclusion: Personnel training, good care of EtO machines, and good ventilation systems should prevent dangerous levels of EtO in the hospital environment.


S. H. D. Mamuya1,2, M. E. Bente1, M. Bråtveit1, Y. Mashalla2.1Section for Occupational Medicine, University Of Bergen, Norway; 2Muhimbili University College of Health Sciences, Dar es Salaam, Tanzania

Introduction: Dust exposure and respiratory health problem in the mining industry have not been studied adequately in Tanzania. Policy makers do not know the magnitude of problems.

Methods: Using a respiratory health questionnaire, 237 coal mine workers were interviewed. A total of 110 respirable dust and 77 quartz samples were analysed. One way analysis of variance and the χ2 test were used for continuous and categorical variables, respectively.

Results: The mean age of the study population was 37 years (range 23.2 to 57.5). The mean personal respirable dust concentration was 3.37 mg/m3 (range 0.05 to 53.86). The mean concentration of quartz was 0.85 mg/m3 (range 0.01 to 16.16). The mean cumulative respirable dust was 10.89 mg/m3 year (range 0.01 to 114.00). Mean cumulative quartz exposure was 0.82 mg/m3 year (range 0.00 to 7.72). There was a high prevalence of respiratory symptoms among the workers: morning cough (25.6%), wheeze (6.9%), dyspnoea 1 (33.3%), and dyspnoea 2 (5.1%). The group with the highest cumulative exposure to respirable dust (>20 mg/m3 year) and cumulative quartz exposure (>4 mg/m3 year) had significantly higher odds ratio (OR) compared with the reference group for cough day and night (3.58 and 3.62 respectively), cough for 4 days or more (4.22 and 6.73 respectively), cough and sputum day and night (3.20 and 6.46 respectively), and dyspnoea (7.64 and 10.91 respectively) after controlling for age and smoking status.

Conclusions: High dust and quartz exposures were found among the workers in the manually operated coal mine. The study showed that the risk of respiratory symptoms increases with the cumulative exposure to respirable dust and quartz.

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