A study on lead exposure indices of male workers exposed to lead less than 1 year in storage battery industries

Hwangbo, Young; Kim, Yong Bae; Lee, Gap Soo; Lee, Sung Soo; Ahn, Kyu Dong; Lee, Byung Kook; Kim, Joung Soon

Abstract

This study intended to obtain an useful information for health management of lead exposed measuring the lead exposure indices and workers and determine biological monitoring interval in early period of exposure by work duration in all male workers (n=433 persons) exposed less than 1 year in 6 storage battery industries and in 49 males who are not exposed to lead as control. The examined variables were blood lead concentration(PBB), Zinc-protoporphyrin concentration(ZPP), Hemoglobin(HB) and personal history; also measured lead concentration in air(PBA) in the workplace. According to the geometric mean of lead concentration in the air, the factories were grouped into three categories: A; When it is below 0.05mg/m3, B; When it is between 0.05 and 0.10mg/m3, and C; When it is above 0.10mg/m3. The results obtained were as follows: 1. The means of blood lead concentration(PBB), ZPP concentration and hemoglobin(HB) in all male workers exposed to lead less than 1 year in storage battery industries were 29.5+/-12.4 microgram/100ml, 52.9+/-30.0 microgram/100ml and 15.2+/-1.1 gm/100ml. 2. The means of blood lead concentration(PBB), ZPP concentration and hemoglobin(HB) in control group were 5.8+/-1.6 microgram/100ml, 30.8+/-12.7 microgram/100ml and 15.7+/-1.6 microgram/100ml, being much lower than that of study group exposed to lead. 3. The means of blood lead concentration and Zpp concentration among group A were 21.9+/-7.6 microgram/100ml, 41.4+/-12.6 microgram/100ml; those of group B were 29.8+/-11.6 microgram/100ml, 52.6+/-27.9 microgram/100ml; those of group C were 37.2+/-13.5 microgram/100ml, 66.3+/-40.7 microgram/100ml. Significant differences were found among three factory group(P<0.01) that was classified by the geometric mean of lead concentration in the air, group A being the lowest. 4. The mean of blood lead concentration of workers who have different work duration(month) was as follows; when the work duration was 1-2 month, it was 24.1+/-12.4 microgram/100ml,; When the work duration was 3-4 month, it was 29.2+/-13.4 microgram/100ml; and it was 28.9+/-34.5 microgram/100ml for the workers who had longer work duration than other. Significant differences were found among work duration group(P<0.05). 5. The mean of ZPP concentration of workers who have different work duration(month) was as follows; When the work duration was 1 2 month, it was 40.6 18.0 g/100ml, When the work duration was 3-4 month, it was 53.4+/-38.4 microgram/100ml; and it was 51.5+/-60.4 microgram/100ml for the workers who had longer work duration than other. Significant differences were found among work duration group(P<0.05). 6. Among total workers(433 person), 18.2% had PBB concentration higher than 40 microgram/100ml and 7.1% had ZPP concentration higher than 100 microgram/100ml; In workers of factory group A, those were 0.9% and 0.0%; In workers of factory group B, those were 17.1% and 6.9%; In workers of factory group C, those were 39.4% and 15.4%. 7. The proportions of total workers(433 person) with blood lead concentration lower than 25 microgram/100ml and ZPP concentration lower than 50 microgram/100ml were 39.7% and 61.9%, respectively; In workers of factory group A, those were 65.5% and 82.3%; In workers of factory group B, those were 36.1% and 60.2%; In workers of factory group C, those were 19.2% and 43.3%. 8. Blood lead concentration (r=0.177, P<0.01), ZPP concentration (r=0.135, P<0.01), log ZPP (r=0.170, P<0.01) and hemoglobin (r=0.096, P<0.05) showed statistically significant correlation with work duration (month). ZPP concentration (r=0.612, P<0.01) and log ZPP(r=0.614, P<0.01) showed statistically significant correlation with blood lead concentration. 9. The slopes of simple linear regression between work duration(month, independent variable) and blood lead concentration(dependent variable) in workplace with low air concentration of lead was less steeper than that of poor working condition with high geometric mean air concentration of lead. The study result indicates that new employees should be provided with biological monitoring including blood lead concentration test and education about personal hygiene and work place management within 3~4 month.