• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.17 no.1
• /
• pp.43-52
• /
• 2007

This study was designed to investigate the difference of airborne lead concentration by type of lead industries and type of lead exposure and to evaluate their association with lead biomarkers of lead workers in 11 lead using industries. Total of 182 lead workers (male: 167, female: 15) from 11 lead industries were participated for this study from March, 2004 to August, 2005. Airborne lead concentration were measured by representative personal sampling of workers in each unit workplace and applied same concentration value to the workers in the same unit workplace who did not measure their airborne lead with personal air sampling. Tibia lead, blood lead, zinc protoporphyrin in whole blood, ${\delta}$-aminolevulinic acid in urine, hemoglobin and hematocrit were selected as study variables of indices of lead exposure. Information about type of lead exposure (fume or non-fume other), age, work duration, smoking & drinking habit were also collected. Significant differences were seen in the means of zinc protoporphyrin, blood lead and tibia lead in lead workers by different airborne lead concentration in workplace. While blood lead and tibia lead in lead workers were significantly higher in secondary smelting than other types of lead industries, zinc protoporphyrin, ${\delta}$-aminolevulinic acid in urine and airborne lead concentration were significantly higher in litharge manufacturing. While the mean blood lead was significantly higher in the lead workers working in fume type unit workplace than those of non-fume lead workers, the mean airborne lead concentration of fume workers was significantly lower than non-fume lead workers. In the multiple regression analysis of airborne lead concentration and the type of lead exposure on tibia lead and lead exposure indices after adjustment of related covariates, airborne lead concentration was statistically significantly associated with blood lead and tibia lead, but the type of lead exposure was only associated with blood lead. To verify the causal association of airborne lead concentration on blood lead and tibia lead, further studies are needed.

• Journal of Nutrition and Health
• /
• v.27 no.1
• /
• pp.12-22
• /
• 1994

Effects of very low level of lead in diet and exposure time on the accumulation and distribution in organs and tissues was investigated with growing rats. 21 days old Sprague-Dawley rats were exposed to lead for 7, 14 and 21 days by feeding of 0.03, 0.42, 0.92 and 1.46mg/kg Pb as Pb-acetate containing diet, respectively. Lead concentrations in blood, liver, kidney and bone exhibit a linear relationship with lead levels in diet. After 7 days of exposure, the greatest dose dependent accumulation of lead was found in kidney and followed in bone. However, after 14 and 21 days, the dose dependent accumlation of lead in bone was about two fold greater than that in kidney. The accumulation of lead in liver and blood was relatively low. As continuous exposure to lead, the concentrations of lead in liver, kidney, blood and intestinal tracts were rather not increased with exposure time. However, bone lead concentration was increased with exposure time by feeding of 0.92 and 1.46mg/kg Pb in diet, but not 0.42mg/kg. The lead concentration in gastrointestinal tracts tends also to increasing with lead levels in diet after 7 and 14 days of exposure. However, by 21 days of exposure the lead concentration revealed relatively constant value regardless of the dietary lead levels. It is concluded that the binding capacity of the lead in blood, liver, kidney and bone seems to be increased with increasing lead levels in diet. The lead concentration in these organs, with the exception of the lead in bone, seems, however, to be standing under steady state regulation by continued exposure with the same dietary lead level. Therefore, by chronic exposure condition with environmental relevant lead level bone might be a principle targe organ for lead and blood lead repesents better the current lead exposure than the lead body burden.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.16 no.4
• /
• pp.324-333
• /
• 2006

This study was designed to investigate the effect of bone demineralization and tibia lead on blood lead in retired lead workers. Two hundred thirty five(126 females and 109 males) retired lead workers who worked in 4 different lead factories and 101 non-occupationally lead exposed subjects(51 females and 51 males) were recruited from March 2004 to October 2004. Bone mineral density(BMD) was measured at left calcaneous bone area by broadband ultrasound attenuation(BUA) method with QUS-2(Metra Biosystems Inc, USA). The BUA value transformed into T-score by WHO standard conversion criteria. Tibia bone lead was measured for skeletal bone lead with K-xray fluorescence(K-XRF) and blood lead was analyzed with flameless atomic spectrophotometer. Hemoglobin, hematocrit, serum calcium and iron were also analyzed. In addition, information for smoking and drinking status and basic personal data such as age, gender and lead exposure were also collected using questionnaire inquiry. Blood lead was correlated with tibia lead (r=0.664) and these two variables were negatively correlated with BMD in bivariate analysis. BMD showed significant main effect on the change of blood lead independent to tibia lead without any effect modification of age or gender; the one T-score unit decrease of mineral bone density made $0.43{\mu}g/dl$ increase of blood lead. On the other hand, tibia lead showed effect modification with gender on blood lead; the slope of tibia lead on blood lead in male was steeper than in female and crossed at around zero of tibia lead. In the multiple regression analysis of blood lead and tibia lead on BMD after adjustment of related covariates, only blood lead showed statistically significant effect on BMD. This study confirmed that BMD and blood lead were significantly associated. To verify the causal association of BMD on blood lead and vice versa, further longitudinal studies are needed.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.20 no.3
• /
• pp.156-167
• /
• 2010

To evaluate the effect of lead biomarkers including bone lead on neurobehavioral test in retired lead workers, 131 retired lead workers without any occupational exposure to organic solvent, mercury and arsenic were agreed to participate this study. For the control subjects 56 non-occupationally lead exposed subjects were recruited from same area of retired lead workers with consideration of demographic characteristics. The mean levels of blood and bone lead of retired lead workers were significantly higher than control group and there were significant correlation among other lead biomarkers. Compared with controls without occupational lead exposure, lead exposured subjects had worse performance on 10 tests out of 12 neurobehavioral tests, but only two tests(Purdue pegboard nondominant and both hand) showed statistical significance of differences. In multiple linear regression analysis of neurobehavioral tests with lead biomarkers and demographic and lifestyle variables, age was associated negatively with 11 neurobehavioral tests, whereas log-transformed ZPP was associated with Purdue pegboard(both hand) and Santa Ana manual dexterity(non-dominant hand). On the other hand, tibia lead was associated Pursuit aiming test(correct) and Purdue pegboard(dominant hand) and calcaneal lead was associated with Purdue pegboard(dominant hand). This study confirmed that among all relevant variables age was most significantly associated with the poor performance of neurobehavioral tests. The blood lead did not have any significant association with neurobehavioral tests, but tibia and calcaneal bone lead and blood ZPP showed significant association with a few tests even after more than mean 9 years from their retirements.

• Safety and Health at Work
• /
• v.2 no.2
• /
• pp.87-96
• /
• 2011

In 1967, the problem of occupational lead exposure came to public attention in Korea. Since then, regular progress has been made in lowering workplace lead exposures, instituting new workplace controls, and implementing health examinations of exposed workers. Past serious lead poisoning episodes made it possible to introduce biological monitoring programs on a voluntary basis in high-lead-exposure facilities in Korea. Industry-specific occupational health services for lead workers in Korea during the last 22 years can be categorized into three phases. During the first phase (1988-1993), efforts were directed at increasing awareness among workers about the hazards of lead exposure, biological monitoring of blood zinc protoporphyrin began, and a respiratory protection program was introduced. During the second phase (1994-1997), a computerized health management system for lead workers was developed, blood-lead measurement was added to biologic monitoring, and engineering controls were introduced in the workplace to lower air-lead levels to comply with air-lead regulations. Finally, during the third phase (1998-present), a new biomarker, bone-lead measurement by X-ray fluorescence, was introduced. Bone-lead measurement proved to be useful for assessing body burden and to demonstrate past lead exposure in retired workers. Occupational health service practice for lead workers, including the industry-specific group occupational health system, has brought considerable success in the prevention of lead poisoning and in reducing the lead burden in Korean lead workers during the last several decades. The successful achievement of prevention of lead poisoning in Korea was a result of the combined efforts of lead workers, employers, relevant government agencies, and academic institutes.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.29 no.2
• /
• pp.195-207
• /
• 2019

Objectives: This study was performed to confirm whether plasma lead can be used as a chronic biomarker for the biological monitoring of exposure to lead. Methods: Lead concentrations in 66 plasma samples from retired lead workers (G.M. 60.25 years, Median 61.00 years) and 42 plasma samples from the general population (G.M. 53.76 years, Median 56.50 years) were measured using ICP/Mass. Tibia, whole blood, hemoglobin, hematocrit, and blood zinc protophorphyrin (ZPP) concentrations and urinary ${\delta}$-aminolevulinic acid (${\delta}-ALA$) were measured for correlation analysis with plasma lead. Results: The geometric mean concentration of lead in plasma was $0.23{\mu}g/L$ for the retired lead workers and $0.10{\mu}g/L$ for the general population sample. A simple correlation analysis of biomarkers showed that plasma lead concentration among the retired lead workers was highly correlated with lead concentration in the tibia and with blood lead concentration, and the plasma lead concentration among the general population correlated with ZPP concentration in the blood. The lead concentration in the tibia and the lead concentration in the whole blood increased with length of working period. As the period in the lead workplace increased, the ratio of lead in plasma to lead concentration in whole blood decreased. Conclusion: This study confirmed the possibility of a chronic biomarker of lead concentration in blood plasma as a biomarker. In the future, comparative studies with specific indicators will lead to more fruitful results.

• Conservation and Restoration of Cultural Heritage
• /
• v.1 no.1
• /
• pp.3-8
• /
• 2012

Chemical compositions and lead isotope ratios for four glass bead samples of Seokga-tap were analyzed and the results were organized. Among 4 glass beads found in the Seokga-tap, 3 pieces were lead glass. Manufacturing method was to firstly grind pebbles finely and mix lead ore to be melt at $740{\sim}760^{\circ}C$. The mixed ratio of silica and lead was 3:7. Moreover, The evaluation on the lead isotope ratio indicated that two lead glass pieces used lead ore from northern Korea. One piece has the direction of southern Korea lead ore, but it requires a further review. One glass bead of Seokga-tap was brown and it was potash lead glass ($K_2O-PbO-SiO_2$) System. The mixed ratio was approximately 50:10:40 for silica, natural saltpeter, and lead, respectively. Lead isotope ratio data fell within the lead ore from northern China. Therefore, it was concluded that potash lead glass found in the Seokga-tap was produced in northern area of China at the end of $10^{th}$ century and transferred to the Seokga-tap.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.21 no.4
• /
• pp.193-200
• /
• 2011

Objectives: Blood lead and hyperhomocysteinemia have been found to be associated with cardiovascular disease. The objective of the present study was to assess the relationship of lead biomarkers on plasma homocysteine and blood pressure. Methods: To evaluate the effect of lead biomarkers including blood lead on plasma homocysteine and blood pressure in retired lead workers, 66 retired lead workers without any occupational exposure to organic solvent, mercury and arsenic were agreed to participate this study. For the control subjects 42 controls were recruited from same area of retired lead workers with consideration of demographic characteristics. Results: The mean levels of blood lead and ZPP of retired lead workers were significantly higher than control group. There were positive significant correlations between blood lead and plasma homocysteine, also systolic and diastolic blood pressure. The multiple linear regression analysis also reveled that plasma homocysteine was significantly associated with blood lead after adjusting for age, gender, body mass index, lead exposure, smoking and drinking. Diastolic blood pressure was significantly associated with blood lead, plasma homocysteine, and total cholesterol; whereas, systolic blood pressure was significantly associated with plasma homocysteine only. Conclusions: Blood lead showed significant association with plasma homocysteine and blood pressure even after more than mean 10 years from their retirements.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.12 s.177
• /
• pp.156-162
• /
• 2005

In this paper, we study the mechanism of lead deformation by numerically simulating the stamping process by means of a commercial finite element code. It is very important to analyze effects that the lead shape makes on the lead deformation, because the lead shape is often modified in order to minimize the deformation or to increase the buckling critical load of the punch. Therefore the stamping process, first, numerically simulated by considering as a quasi-static problem. Second, the effect on the lead deformation due to the lead shape variation, a linear lead geometry and a bent lead, was numerically analyzed and discussed. Finally, the punching order was optimized fur multi-lead generating stamping process. The results show that the bent lead is little bit more shifted than the linear lead after the punching process. But the bent lead is vertically less deformed than the linear lead. The punching order to successively generate the lead is good to keep the lead space uniform. The results will be very effectively applied for the design of the blanking or punching dies in industry.

• Journal of Nutrition and Health
• /
• v.38 no.1
• /
• pp.48-55
• /
• 2005

Chitosan, which is a biopolymer, composed of glucosamine units linked by $\beta$-1, 4 glycoside bonds, is rich in shells of crustacean such as crabs and shrimps. Consumption of chitosan has been rapidly increased as a functional food. We examined effects of chitosan on the damages caused by lead (Pb) exposure in rats. Male Sprague-Dawley rats were divided into 8 groups (n = 64), then fed diets containing 3% cellulose (control) or 3% chitosan, each with 4 different lead doses (0 mg/d, 20 mg/d, 50 mg/d, and 100 mg/d) for 4 wks. Lead doses were given 3 times per week by oral administration. Blood lead levels in rats increased depending on the administered doses of lead. Rats fed chitosan diets showed lower blood lead concentration than did their respective controls. Effect of chitosan on the blood lead was more beneficial in rats exposed to lower lead (20 mg/d) than in rats exposed to higher lead (50 mg/d and 100 mg/d). Histological changes in erythrocytes and liver were also examined. Chitosan tended to reduce numbers of basophilic stippling erythrocytes and improve the histological liver changes in rats given various lead doses. The preventive effects of chitosan on liver damages were stronger in rats with higher lead than those with lower lead. These results indicate that chitosan has beneficial effects on both blood toxicological responses and histological damages of erythrocytes and liver induced by the administration of various lead doses.