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Title: Workplace and home exposure to respiratory sensitisers : examining the work to home pathway
Author: Anua, Siti Marwanis
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2012
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Background: Contamination of the skin and clothing may lead to workers inadvertently bringing harmful materials home and exposing family members, so called para-occupational exposure. This study investigates whether workplace contamination with respiratory sensitisers such as laboratory animal allergens, flour, isocyanates and enzymes is transported from work to the home environment. Methods: 3 laboratory animal facilities, 92 bakeries, 47 car body workshops, and 2 hospitals in the Grampian region of Scotland were invited to take part in a series of linked studies to increase understanding of the ‘take-home' pathway. Control subjects were recruited from staff and students at the University of Aberdeen. Take-home exposure assessment was carried out using two techniques: surface wipe sampling and vacuum sampling in workplaces, cars and homes. Samples were also collected in the homes of control subjects. Samples from bakers were analysed for total protein, wheat flour antigen (WFA) and fungal alpha amylase (FAA) while samples from laboratory animal workers were analysed for mouse urinary protein (Mus m 1). Enzyme cleaning agents were analysed for subtilisin proteolytic activity. Similar methods using SWYPE™ aliphatic pads for isocyanate contamination assessment were conducted among car body repairers. The pads were scanned and images of SWYPE™ pads were used to estimate contamination against the quantitative assay MDHS 25/3. All analyses were done by the Health and Safety Laboratory (HSL) apart from the SWYPE™ RGB tests and gravimetric measurements. Results: A total of 13 laboratory animal workers in 3 animal facilities, 38 bakers in 5 bakeries, 13 car painters in 5 car body workshops and 20 control subjects participated in the study. Two hospitals were surveyed for enzyme exposures and 3 endoscope cleaning technicians were monitored. Evidence of take-home exposure was found for bakery workers, with potential contamination that could lead to home exposure in the car body repair and hospital workers. Higher levels of Mus m 1 contamination were detected on house door handles of non-exposed controls compared to the exposed laboratory workers (0.62 vs. 0.1 ng/wipe, p<0.001) probably due to exposure variability, might be because exposed laboratory workers being involved in a job that requires more hand washing than the general population, or suggesting widespread environmental contamination with this allergen, and these making it impossible to determine if work-home pathway exists for these workers. There was detectable WFA and FAA found on the hands, forehead, shoes, cars and homes of bakers. Compared to controls, bakers had higher median levels of WFA and FAA in house vacuum samples; the difference was statistically significant for WFA/total protein (516x10-6 vs. 164x10-6, p=0.031), FAA/total protein ratios (1.45x10-6 vs. 0.04x10-6, p<0.001) and FAA loading (1.2 pg/cm2 vs. 0.1 pg/cm2, p<0.001). Among car painters, SWYPE™ colorimetric colour changes score showed three positive SWYPE™ colour changes on skin, and three positive results on shoes of car body workshop workers. However quantitative colour analysis of the SWYPE™ pads proved ineffective for field measurements. Hand wipes of hospital workers during mid-shift and post-shift showed evidence of proteolytic activity, indicating possible spread of contamination from hands, unsatisfactory hygiene practices and the potential for take-home contamination of enzyme. Presence of contamination on footwear indicated that possible transfer of enzyme to other places including homes may occur. Conclusion: These data demonstrate the existence of pathways for take-home exposure of allergens among bakers via skin and clothing from workplaces to cars and workers' homes. The take-home pathway for laboratory animal allergens and isocyanates was not demonstrated and further investigation should be performed for enzyme cleaning agents used in healthcare settings by monitoring dermal take-home exposure with comparison to controls. Further work is needed to ascertain how widespread the take-home of respiratory sensitisers may be and the possible implications to the health of workers' families and the wider community. If parental occupation can lead to take-home exposure to respiratory asthmagens, and consequently to childhood asthma, then this represents a potentially modifiable risk factor for these cases of para-occupational asthma. There is a need for greater understanding of the take-home pathway of exposure to asthmagens and sensitisers and for a programme of education and control measures to limit the transfer of such material from the workplace to the home and wider community.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Bakery employees ; Automobile industry workers ; Respiratory organs ; Occupational diseases