Objective To compare hazards of occupational lead exposure evaluated with three different occupational health risk assessment methods in a lead acid battery enterprise and to provide evidences for efficient implementation of occupational health risk assessment in enterprises.
Methods We conducted an occupational health survey, including field study, monitoring on workplaces' lead smoke/dust and sulfuric acid concentration, and detection of blood lead among exposed workers in a lead-acid battery company in Jiangsu province. Then we analyzed the data collected using International Council on Mining and Metals (ICMM) model, Control of Substances Hazardous to Health (COSHH Essentials), and composite index method to evaluate health hazards of lead exposure among workers at main work sites. We compared the standardized risk ratios resulted from the three methods and adopted rate of abnormal blood lead as references to select a more accurate assessment method.
Results When the concentration of hazardous substances ranging between 1/2 of and equal to the threshold limit value, a moderate health risk in relation to exposures at work sites of gel electrolyte mixing and acid adding was identified consistently by the three assessment methods. When the concentration of hazardous substances being higher than the threshold limit value, a high health risk relevant to exposures at work sites of plate casting, sheet grinding, sheet dividing, and welding was detected with the COSHH Essentials method and composite index method. Whereas, when the concentration of hazardous substances being lower than a half of the threshold limit value, the estimated health risk associated with exposures at work sites of ball milling and sheet plastering were inconsistent for the three methods; but a moderate health risk related to the two work sites' exposure was derived based on the evaluation of composite index method and blood lead abnormal rate.
Conclusion The composite index method is appropriate to lead-related occupational health risk assessment at various exposure conditions in lead acid battery factory.
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