A Preliminary Study On Biomarkers Of Lung Injury In Rare Earth Exposed Occupational Population

Objective In this study,rare earth miners exposed to rare earth dust were selected as the target population,and local winery workers were selected as the control group.By monitoring dust concentration in workers’workplaces,lung injury markers,systemic inflammation levels,and evaluating comprehensively the lung function level of population,the early effects of rare earth exposure on lung injury in workers were discussed.Methods In this study,a rare earth concentration mine and a white distillery in Baotou were selected as the exposed enterprise and the control enterprise.Workers exposed to rare earth in target enterprise and non-raw material workshop workers in control enterprise were studied.Spot sampling and individual sampling were used to detect dust concentration in the workplace.Through the questionnaire survey,the basic information,life information and occupational history of the research objects were collected.Epidata3.1 was used for double entry and verification of the questionnaire.Lung function was detected in the study population,and peripheral blood samples were collected to detect peripheral blood cells,serum CC16,serum CRP and serum creatinine.The data obtained were statistically analyzed.Results 1.The exposed workshops to rare earth dust are mainly roasting workshops,water-soaking workshops and carbon-sinking workshops.The average daily PM_2.5 concentration of the dust is 1.253 mg/m³,0.127 mg/m³ and 0.612 mg/m³,respectively during normal producting.2.The average concentration of individual dust in calcining workshop,water immersion workshop and carbon sinking workshop was 1.33 mg/m3（0.82-2.38）、1.29 mg/m3（0.60-2.88）、0.77mg/m3（0.41-1.03）.Among them,the higher concentration of the works are the mechanic workers and the mixers of calcining workshop and the mechanic workers,the plate workers,the frame workers of the water immersion workshop.3.The results of blood cell analysis:The levels of leucocyte,neutrophils,lymphocytes,monocytes and eosinophilic cells in the exposed group are higher than those in the control group,and the difference is statistically significant（all P<0.05）.The red blood cell count and hemoglobin levels of the exposed group are lower than those of the control group,with statistically significant differences（all P<0.05）.The leucocyte,lymphocyte,mononuclear cell and eosinophilic cell counts of the exposed group are higher than those of the control group（all P<0.05）.In the exposed group,there is no statistically significant difference between theleucocyte and the classified cell count,the hemoglobin level and the platelets of smokers and non-smokers（all P>0.05）.In the control group,the levels of leucocyte,neutrophils,lymphocytes,eosinophils and hemoglobin in smokers are all higher than those in non-smokers,with statistically significant differences（all P<0.05）.The leucocyte and neutrophil levels of workers within 5.8 working years of dust exposure are the highest,and the differences were statistically significant at different working ages（all P<0.05）.4.Results of lung function examination:the levels of VC,FVC,FEV₁,FEV₃,FEV₆,PEF and MEF₇₅ in the exposed group are all lower than those in the control group,and the differences are statistically significant（all P<0.05）.After the stratification of the whole population,only FVC,FEV₆,PEF and MEF₇₅of the exposed people in the non-smoking group are found to be lower than that of the control group,with statistically significant differences（all P<0.05）.No difference in lung function is found in the exposed group after dust exposure age stratification.5.Serum CRP test results:The CRP level of the rare-earth dust exposure group is 2.3 times that of the control group,and the difference was statistically significant（P<0.001）.The serum CRP levels of smokers and non-smokers exposed to rare-earth dust are 1.8 times and 1.7 times higher than those of the control group,respectively,with statistically significant differences（P=0.008and P=0.003）.There is a significant difference in CRP level（P<0.001）within different ages of dust exposure.6.The results of serum CC16:There is no statistically significant difference in serum CC16 level between the exposed group and the control group（P=0.259）.Among smokers and nonsmokers,there are no statistically significant difference in serum CC16 levels between the exposed and control groups（P=0.065 and P=0.961）.And there are no statistically significant difference in serum CC16 among different ages of dust exposure in exposed group（P=0.799）.7.After the correlation analysis of lung function,serum CRP and serum CC16,it is found that there is a positive correlation between lung function FEV₁、FEV₁/FVC、PEF、MEF₇₅ and serum CC16.Conclusion 1.The workshops that produce dust in rare earth mining enterprises are mainly roasting workshop,water leaching workshop and carbon deposition workshop,among which the roasting workshop has the highest dust concentration.2.The key work types of dust hazard control in rare earth mining enterprises are mechanic,material mixer,plate frame worker and pressing plate worker.Personal protection should be strengthened,and even working time should be shortened.3.After exposure to rare earth dust,leukocytes,neutrophils,lymphocytes,monocytes and eosinophils increased,among which leukocytes and neutrophils are the highest within 5.8 years.4.Long term exposure to rare earth dust will lead to the decrease of lung function and the increase of serum CRP level.5.There is a positive correlation between CC16and FEV₁、FEV₁/FVC、PEF、MEF₇₅,etc.