Study On Health Effect Of Benzene Exposure On Shoe Manufacture Workers

BackgroundBenzene, a colorless transparent liquid with a sweet odor, is widely used in industry.Shoes manufacturers mostly use the mastic and disposal agent containing benzene aschemical materials. Benzene evaporates into human body mainly through the respiratorysystem and accumulates in organs such as bone marrow and liver and so forth. The mainchronic toxicity of benzene is injuring hematopoietic system which results in the decreaseof leucocyte, blood platelet and erythrocyte.Compared with control group, it is observed in benzene exposure workers group thattheir leucocyte, blood platelet and erythrocyte counts decreased. At present, although thereis a coincident conclusion obtained in the research on peripheral blood cell and exposure tohigh density of benzene, there is still no certain conclusion on what effect will be caused onhuman body health when expose to low density benzene and whether this will causedamage of peripheral blood cell and hepatic function.Similar exposure group refers to a group of workers with same exposure characteristics.They execute the same task by the same way, and expose to similar substance whilecompleting similar operation. So the limited resources can be effectively utilized tocomplete exposure evaluation at larger work site in a short time by adopting similarexposure group method.The current condition study and longitudinal data analysis were conducted toinvestigate the condition of peripheral hemogram and hepatic function in benzene exposuregroup and the distribution of the gender, age, working years, workshop and so on, in orderto evaluate the risk of relevant influential factor. Meanwhile, the dose-effect relation of benzene exposure and health effect was investigated by similar exposure group method,with aims to provide scientific basis for corresponding precaution.Materials and MethodsIn current condition study, 1403 workers from certain shoes factory were selected asbenzene exposure group and 585 healthy individuals were randomly selected as the controlgroup. The questionnaires, which unified and estimated in advance, were adopted toinvestigate 826 operational workers. The contents of this survey included age, education,benzene exposure, utilization of protective equipments, occupational health knowledge,behavior mode information and so on. Occupational health examination was conducted tobenzene exposure group and control group. The blood serum alanine transaminase (ALT),aspartic acid transaminase (AST) andγ-glutamyl transpeptidase (GGT) were examined bybiochemical methods; the white blood cell (WBC), red blood cell (RBC), haematoglobin(HGB), blood platelet (PLT) were examined by automatic hemocyte analysis, hermaldesorption vapor phase chromatography was adopted to monitor the density of benzene inthe air of workshop; and headspace gas chromatography adopted to monitor the density ofbenzene in 26 mastic samples in this study.ResultsQuestionnaire was adopted to investigate 826 workers selected by cluster sampling inshoes manufacture. The result of Logistic regression analysis shows that there wassignificant difference in peripheral blood cell abnormality with educational level,utilization of protective equipments, and consciousness of occupational diseaseprevention and control; there was no significant difference with age, body mass index,smoking, drinking and physical exercise participation.The results of occupational health examination showed that there were 201 (14.3%)abnormal samples in total 1402 samples that received WBC detection, 148 (10.6%)abnormal samples in total 1400 samples that received RBC detection, 170(12.2%) abnormal samples in total 1401 samples that received HGB detection, 3(0.2%) abnormalsamples in total 1401 samples that received PLT detection, 84(6.0%) abnormal samples intotal 1403 samples that received ALT examination, 66(4.7%) abnormal samples in total1403 samples that adopted AST examination, and 17(1.2%) abnormal samples in total 1403samples that adopted GGT examination. There were statistically significant differencesbetween benzene exposure group and control group on the abnormality of WBC, RBC,HGB, ALT and AST, while there was no statistically significant difference in abnormalityof PLT and GGT.Headspace gas chromatography was adopted to determinate benze.ne, Toluene andXylene of chemistries used in shoes factory and found there were benzene detected in packhead adhesive, treating agent and cleaner. Thermal desorption gas chromatography wasadopted to determinate Benzene, Toluene and Xylene in workshop and according toobservation method combined with sample drawing method to divide samples into similarexposure group including high density similar exposure group and low density similarexposure group After examination, the result shows there is significant difference in eachexposure group.The analysis of effective factor of WBC abnormality in object investigated showed:after Logistic regression analysis, the results analyzed of WBC abnormality with workshopand similar exposure group were as below: for injection mould workshop OR=9.193,(95%CI:1.219-69.336) and for packing workshop OR=12.820, (95%CI: 1.666-98.659), forhigh density benzene exposure OR=3.027,(95%CI: 1.189-7.705). the results analyzed ofRBC with similar benzene exposure group and gender were as below: for high densitybenzene exposure OR=24.367,(95% CI: 9.407-63.118), for low density benzene exposureOR=14.056,(95% CI: 5.403-36.568),compared with male, for female OR=25.055,(95%CI:12.331-50.912); the results analyzed of HGB with similar benzene exposure group andgender were as below: compared with control group, for high density benzene exposureOR=3.200, (95%CI: 2.000-5.118), compared with male, for female OR=7.095,(95%CI:4.395-11.450).Longitudinal data analysis in 163 samples indicated that low density benzeneexposure for two years caused significant decrease in WBC counts which the reduced amount was 0.41 units in average; low density benzene exposure for one year causeddecrease in RBC counts which the reduced amount was 0.18 units and recover to normallevel after low density benzene exposure for two years. There was no significant changein HGB and PLT counts after low density benzene exposure for two year.ConclusionsCompared with the control group, the abnormality ratio of WBC, RBC, HGB, ALT,and AST of benzene exposure group showed significantly increasing.The abnormality ratio of WBC, RBC and HGB increased significantly owing to thehigh density benzene exposure. While low density benzene exposure caused RBCabnormality ratio increasing, but not that of the abnormality ratio of WBC and HGB.Longitudinal data analysis showed that low density benzene exposure for two yearscaused significantly decreasing in WBC Counts which the reduced amount was 0.41 units,and low density benzene exposure for one year caused decreasing in RBC counts which thereduced amount was 0.18 units and recover to normal level after low density benzeneexposure for two years.There were significant differences in RBC and HGB counts with different gender.Compared with male, benzene exposure significantly affected RBC and HGB and tend tocause RBC and HGB abnormality in female.