Journal of School of Public Health and

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The purpose of this study was to measure ambient lead concentrations in Tehran's 12th Municipal District and also Pb concentrations in urine samples from municipal workers assigned to the same region. In this research workers from the 12th District were matched and compared with a control group who were doing the same type of work in another region in northern Tehran with lighter traffic and comparatively clean air.Air samples were analyzed by atomic absorption techniques. Results showed the mean air concentration of lead to be higher than standard (1.5ug/m3) except on Fridays and Thursdays (1.9±0.32). The end-shift urine samples were prepared and analyzed using the HSE method. Lead levels in 77.1% of the urine samples were higher than HSE-recommended limits (643.86±353.73). The independent t-testindicated that the mean urine Pb concentration in the case group was significantly higher than in controls (p<0.001). Mean urine lead levels in smokers were significantly higher than non-smokers in case group (p^0.043). The Pearson Correlation test showed a significant relationship between urine Pb concentration and age, duration of employment, and smoking habit in case workers (r=0.427, p= 0.011, r=0.385, p=0.632 and r=0.632, p=0.009 respectively). Also, the Kruskal-Wallis test indicated that urine lead levels were independent of the workers'education level and work shifts.

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Background and Aim: Lead is a toxic metal used in different industries and occupational and environmental exposure to it is quite likely to occur. Because of its high potential toxicity, serious damages to those exposed to it are common. Since the ceramic industry, in which lead is used, is considered a domestic industry in Iran, in this study occupational exposure of glaze workers to lead was assessed in a ceramic industry.

Materials and Methods: A total of 55 glaze workers (39 tillers and 16 potters) were selected as the case group. Association of lead concentration with several variables, including work shift, work type, ventilation system, and the number of extra work hours during the previous month, was determined. A sampling pump (SKC Co.) and ester cellulose filters with a pore size of 0.8 µm, 37 mm in diameter, were used for sampling. The flow-rate was adjusted at 2 l/min based on the NIOSH 7300 method. After sampling, filters were transferred to the laboratory and digested in a mixture of nitric acid and per chlorate solution (4:1) and analyzed by ICP-AES. To minimize probable errors and pollution during sampling and sample handling, samples were also taken from employees in the administration department to serve as control. Spiro metric tests were performed on both the case and the control groups.

Results: The lead concentrations were higher than the threshold limit value (TLV) (0.17 mg/m). Independent t-test showed that there was a significant relation between concentration of the lead present in the breathing zone air and 2 independent variables, including shifts work (morning and afternoon) and the ventilation system among tillers. Also, based on the one-way ANOVA, there was a significant relation between concentration of the lead present in the breathing zone and the number of extra working hours over the shift.

Conclusion: The mean lead concentration in the breathing zone was higher than the respective TLV. Considering the hazardous nature of lead, protective measures─ personal, occupational and environmental─ should be taken. Moreover, clinical examination of job applicants at the time of employment, as well as periodic examinations and Spiro metric tests on the workers, are also strongly recommended.