Study On The Biomarkers In Workers Exposed To Lead

Objective:Lead (Pb), as a heavy metal element, its harm always exists. Despite the prevention and control measures of lead poisoning has been taken for many years, lead hazard problem remains unresolved in various process steps of the storage battery manufacturing industry. The study based on the research of the occupational health of a city's battery manufacturing industry, the contact groups and the comparison groups were selected for study cohort. The occupational health checkup, micronucleus test, chromosomal aberration test and comet assay were used in the study to determine the effects of exposure to lead, and explore the genetic damage effect of the lead and select suitable markers of exposure and genetic damage effect. Meanwhile, the concentration of the lead fume and lead dust in the air were inspected in the storage battery workplaces to evaluating the level of lead hazard and the protective facility, and provide a scientific basis for taking concrete interventions measure.Methods:This study includes three parts. In the first part, we investigated the occupational health current situation by epidemiological field investigation and detected the lead fume and dust concentrations in workplace. Secondly, 187 workers exposed to lead who came from three factories where the protective facilities were good, normal and poor were chosen. Red blood cells, platelets, blood lead, urine lead and zinc porphyrin were studied to analyze the health effects in occupational exposure workers. Finally, comet assay, micronucleus and chromosomal aberration test were used to study and estimate the genetic damage effect of lead on occupational exposure workers.Result:As showed in epidemiological survey, the production scale of storage battery factories in a city is small, with low degree automation, poor equipment and lack of protective facility. The occupational health management is not standardized. The qualification rate of lead concentrations in the workplace is only 36.4%.The test results of exposure and effect markers showed that the rate of occupational exposure whose urine lead, blood lead and zinc porphyrin exceeding the occupational exposure limits were 69.5%, 16.0% and 36.9% respectively. The urine lead and blood lead or the number of people whose urine or blood lead levels exceeding the occupational exposure limit in the study group were found to be significantly higher than those of the controls(P<0.001). The urine lead, blood lead and zinc porphyrin levels of workers exposed to lead in poor or normal protective facility factories were higher than those in good-protective facility factory, and there was a significant difference (P<0.05). The hemoglobin in lead exposed group was significantly lower than those in the same sex control group (men P<0.001, women P<0.05). The platelet count in lead exposed group was also significantly lower than that in the same sex control group (men, women P<0.001). There was no any difference between red blood cell of lead-exposed group and the same sex control group(P>0.1).The results of the effects of genetic damage studies showed that the comet cell rate, the comet tail length, the micronucleus rate and the chromosomal aberration rate in lead-exposed group were 37.4%,3.48±0.94μm,0.262‰and 0.045% respectively.All those biomarkers were observed to be statistically significant increases in the exposed group compared with the controls (the comet cell rate, the comet tail length and the micronucleus rate P<0.001, the chromosomal aberration rate P<0.05). There was increasing tend of the rate of comet by the increase of blood lead or urine lead. There was obvious difference between each study group and control group (P<0.05). However there was no any difference among each comet tail length. Only when blood lead was over 1.45μmol/L or urine lead was over 0.58μmol/L, the rate of micronucleus significantly increased compared with the controls (P<0.001).Conclusion:Lead damages health of occupational exposure cohort and results in the genetic damage. The urine lead, blood lead and zinc porphyrin levels of workers exposed to lead could be used as biomarkers. Comet assay can be used as genetic damage effective biomarker in workers occupationally exposed to lead, which was more simply and sensitively than micronucleus test and chromosome aberration test. It should be noted the cross links of DNA-protein. There is a better application prospect of comet rate as monitoring index of occupational exposure to lead in the early stage.