The Influence Of MTBE Exposure To Health And Genetic Damage Of Filling Station Attendants

Objective:Used the health risk assessment model which was recommended by EPA,combined with the levels of methyl tert-butyl ether (MTBE) in occupational air,ambient air, drinking water and questionnaire survey to preliminary evaluate thehealth risk of filling station attendants by multi-channel MTBE exposure. Onthis basis, recruit filling station attendants from Nanning city Participate inoccupational health examination, to understand the effect of MTBE exposure ofworkers. The micronucleus test of exfoliated oral mucosa cells and serumconcentrations of MTBE and TBA were used to explore the relationship offilling station attendants’genetic damage and MTBE exposure.Methods:1. Chose filling station attendants from Nanning city as a research objectand used questionnaires to collect the exposure parameters of workers such assex, weight, expose time and expose frequency. In addition, on-siteenvironmental monitoring methods were used to monitor the MTBEconcentrations in occupational air, ambient air and drinking water, and then usethe multiple exposure models to evaluate the health risk of filling stationattendants 2. Chose the workers from Petroleum Company in Nanning who participatein occupational health examination in2012as a research object. The lineworkers (the operating workers) as the exposed group, the non-frontline workers(the stationmaster, the card issuing staff, the salesperson, etc.) as theinner-control group, used the occupational epidemiological investigationquestionnaires to carry out the baseline survey including the demographicinformation, living habits, history of diseases and occupational history,combined the results of the occupational health examination of workers toevaluate the health effects of MTBE exposure.3. Chose filling station attendants who participate in occupational healthexamination as the exposed group and the inner-control group, the adultresidents who were not in contact with the MTBE and other occupationalhazards as the control group. Then all subjects were collected exfoliated oralmucosa cells for the micronucleus test, and were collected the peripheral venousblood to detect the MTBE、TBA levels in the serum by using HS-SPME-GC/MS.Finally, the OMN and the MTBE、TBA levels in the serum were compared inthe three groups, and then the relationship between the OMN and the MTBE、TBA levels in the serum were analyzed to evaluate the genetic damage ofworker exposure to MTBE.Results:1. The results of environmental monitoring showed that the highestconcentration of MTBE was find in occupational environmental, followed byambient air, the lowest concentration of MTBE was in drinking water. Foroccupational environmental, MTBE concentrations in operating area was higherthan office area, urban districts was higher than suburban districts. The order of mean air concentrations of MTBE in filing station was urban operating area>suburban operating area> urban office area> suburban office area.2. The results of health risk assessment of MTBE exposure showed that thehighest health risk was obtained in filling station attendants being exposed byoccupational air, followed by ambient air, the lowest was obtained by drinkingwater. The total carcinogenic risks of MTBE for filling station attendants wererange between2.01×10-6to1.34×10-5. The lowest carcinogenic risk wasobtained in male office workers of the suburban district, the highestcarcinogenic risk was obtained in female operating workers of the urban district.The total non-carcinogenic risks of MTBE for filling station attendants wererange between1.92×10-2to1.55×10-1. The lowest carcinogenic risk wasobtained in male office workers of the suburban district, the highestcarcinogenic risk was obtained in female operating workers of the urban district.3. The physical examinations showed that the abnormal rate of routineurine was40.8%which was the highest, followed by abdominal B ultrasound,the abnormal rate was30.6%, the abnormal rate of RBC, electrocardiogram,hemoglobin(ECG), and blood pressure was>10%, the abnormal rate of WBC,AST and ALT were6.6%,8.6%and7.3%. compared the results of physicalexaminations between exposure group and inner-control group, the resultsshowed that the abnormal rate of physical examinations of exposure group washigher than inner-control group(P<0.05).4. The results of MTBE exposure to filling station attendants geneticdamage showed that the serum concentration of MTBE, TBA were significantdifferences in the exposure group, the inner-control group and the controlgroup(P<0.05). The OMN of exposure group was significant higher than other two groups (P<0.05). The OMN of exposed group was increasing by theconcentrations of MTBE in the environmental and the workers seniority. Theresults of the relationship between the serum MTBE, TBA levels and OMNshowed that the serum MTBE, TBA levels were significant positive correlationwith OMN (P<0.05).Conclusions:1. The non-carcinogenic risks of MTBE expose of filling station attendantswere lower than1, suggesting that expose to MTBE by drinking water, ambientair and occupational air were not expected to pose significant non-carcinogenicrisk health effects. The total carcinogenic risks of filling station attendants werein the range of occupational safe limits (1×106and1×104), but over theacceptable risk levels of population (10-6), indicated that the potential risk ofMTBE exposure were obtained in filling stations.2. Occupational MTBE exposure can cause different degrees of healthdamage to workers, mostly seen were the routine urine, abdominal B ultrasound,routine blood and liver function abnormalities.3. Occupational exposure to MTBE can lead to OMN frequency increasedand caused genetic damage of workers. The serum concentration of MTBE andTBA has a significant positive correlation with workers OMN frequency,showing a significant dose-effect relationship. The micronucleus test ofexfoliated oral mucosa cells can be considered as indicators of genetic damageof filling station attendants expose to MTBE.