For the purpose o investigating the effect of respiratory protection with biological monitoring on the improvement of workers' health, authors selected one storage battery factory which was scheduled to move to a new modernized factory within 2
years.
Maintenance free respirators were provided to all of the workers at the beginning of this study for the respiratory protection.
Zinc protoporphyrin (ZPP) in whole blood was chosen as an index of biological monitoring and was measured regularly once a month throughout 1 year-study period. Blood lead (PBB), δ-aminolevulinic acid in urine (ALAU), hemoglobin, hematocrit,
lead
related symtoms and other personal data were also checked twice at the beginning and the end of this study, respectively. Fourteen questionnaires of lead absorption were completed by each worker twice at the beginning and the end of this study,
respectively.
Out of 214 workers, authors analysed the data of 147 workers who stayed during the study period from the beginning to the end of this study, @ES and the results obtained were as follows:
@EN 1. The percentages of workers whose blood lead was over 60ug/dl and blood ZPP over 150ug/dl which were the criteria for the diagnosis of lead poisoning in Safety and Health Act of Korea decreased from 23.7% and 23.0% at the beginning of the
study to
1.3% and 1.9% at the end of the study, respectively.
2. There were significant differences of mean value in blood lead, ALAU, ZPP and overall prevalence rate of lead related symptoms between the beginning and the end of the study, but there were no differences of mean value in hemoglobin and
hemotocrit
between two periods.
3. While the most frequent three symptoms in male workers were "feeling tired generally", "loss of weight" and "numbness of fingers, hands or feet" in order, those in female workers were "numbness of fingers, hands or feet", "feeling tired
generally"
and "loss of weight" in order of frequency.
4. The prevalences of two symptoms ("cann't sleep well" and "loss of weight") increased significantly by the increase of blood lead of workers.
5. The prevalences of six symptoms ("anorexia", "numbness of fingers, hands or feet", "weakness of fingers, hands or feet", "joint pain" and "feeling tired generally") increased significantly by the increase of blood ZPP of workers.
6. The variable which showed highest correlation with overall prevalence of lead related symptoms was blood ZPP and there was also significant correlation between symptom prevalence and blood lead an ALAU.
7. There were negative correlations between symptom prevalence and age and work duration. As the age and the work duration of workers increased the symptom prevalences were decreased accordingly.
8. Stepwise multiple regression analysis using overall symptom prevalence as a dependent variable and blood lead, ALAU, hemoglobin, hematocrit, work duration, age, sex as independent variables, indicated that only blood ZPP and age were
significantly
contributed to the dependent variable.
With above results it was confirmed that respiratory protection with biological monitoring using blood ZPP could improve workers' health by reducing the degree of lead exposure, and blood ZPP was found to be the most relevant index to lead
related
symptoms.
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