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ObjectiveTo understand the concentration levels of benzene， toluene and xylene in the workplaces of enterprises involved in benzene and benzene series in Jinshan District， and to provide the basis for the government to formulate key occupational disease prevention and control strategies. MethodsFrom 2016 to 2021， enterprises involved in benzene and benzene series were sampled individually， and the monitoring results of benzene and benzene series were statistically analyzed through workplace air sampling and laboratory detection. ResultsFrom 2016 to 2021， a total of 80 enterprises were monitored， and the total passing rate of individual monitoring was 87.50%， which decreased first and then increased. The difference was not statistically significant. A total of 387 individuals were sampled with a total passing rate of 95.61% and a detection rate of 73.38% （284 individuals）. The detection rates of benzene， toluene and xylene were 6.46%， 29.97% and 36.95%， respectively. The exceedance rates were 1.03%， 0.26% and 3.10%， respectively. Among the companies exceeding the standard， the metal products industry had the highest rate of exceedance （19.05%）. For individuals， those working in the printing and recording media reproduction industry had the highest rate of exceedance （10.26%）. ConclusionThe passing rate and detection rate of benzene and benzene series are relatively high in Jinshan District. The metal products industry and the printing and recording media reproduction industry have a higher exceedance rate of benzene and benzene series.
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OBJECTIVE: To explore the effects of combined exposure to low-level benzene derivatives and noise on hearing loss of workers. METHODS: A total of 216 employees from nine wood furniture factories and four printing factories were selected as research subjects by typical sampling method. Those without exposure to occupational hazardous factors were set as the control group, those exposed to noise alone were set as the noise group, and those exposed to benzene derivatives and noise were set as the combined exposure group. The normalization of equivalent continuous A-weighted sound pressure level to a nominal 8 hours working day(L_(EX,8 h)) and the exposure concentration of time weighted average(C_(TWA)) of benzene, toluene, xylene, ethylbenzene in the workplace air of the three groups were detected, and the hearing threshold of 0.5-8.0 kHz in both ears of the research subjects were measured by pure tone audiometry. RESULTS: No benzene was detected in the workplace air of the combined exposure group, and the C_(TWA) of toluene, xylene and ethylbenzene were all lower than the occupational exposure limits. The L_(EX,8 h) of the noise group and combined exposure group were all higher than that of the control group [(85.6±2.5) vs(68.7±4.4) dB(A),(84.3±3.1) vs(68.7±4.4) dB(A), all P<0.05], while the L_(EX,8 h) of the noise group was higher than that of the combined exposure group [(85.6±2.5) vs(84.3±3.1) dB(A), P<0.05]. Compared with the control group, the individual frequency hearing thresholds, average hearing threshold of speech frequency and average hearing threshold of high frequency in both ears in the noise group and the combined exposure group were increased(all P<0.05), and the detection rates of speech frequency hearing loss and high frequency hearing loss were increased(all P<0.02). The hearing thresholds of right ear of 0.5, 1.0 kHz and left ear of 0.5 kHz were increased in the combined exposure group(all P<0.05), and the detection rate of speech frequency hearing loss was increased(16.7% vs 40.8%, P<0.02), when compared with the noise group. Multivariate logistic regression analysis results showed that the risk of speech frequency hearing loss and high frequency hearing loss in the combined exposure group were higher than that in the control group and the noise group(all P<0.05), after excluding the influence of confounding factors such as education level and smoking.CONCLUSION: The combined exposure to low-level benzene derivatives and noise may have a synergistic effect on the hearing loss in workers.
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OBJECTIVE: To explore the combined effect of noise and other occupational hazards on hearing impairment and electrocardiograph(ECG) of workers in automobile manufacturing enterprises. METHODS: A judgment sampling method was used to select 3 434 workers as study subjects from an automobile manufacture enterprise. According to the exposure to different types of occupational hazardous factors, they were divided into noise series group, noise dust group, noise welding dust group, noise benzene series group, noise nitrogen oxide group and control group, with 716, 693, 1 540, 45, 195 and 245 cases in each group, respectively. The subjects were examined with pure-tone hearing test and ECG. RESULTS: The total rate of high frequency hearing loss was 11.2%(385/3 434), and high frequency hearing loss was the main type of hearing loss among workers in each group. The simple high-frequency hearing loss rates of noise group, noise dust group, noise welding dust group, noise benzene series group, noise nitrogen oxide group and the control group were 10.3%, 11.5%, 12.3%, 26.7%, 10.3% and 4.1% respectively, and the rate of total hearing loss were 13.7%, 14.6%, 14.6%, 31.1%, 16.9% and 6.5% respectively. Compared with the control group, the rate of simple high-frequency hearing loss and total hearing loss were higher in the other 5 groups(P<0.005). The rate of high-frequency hearing loss in noise group was lower than that in noise benzene series group(P<0.005). The rate of arrhythmia was 20.9%(717/3 434). Arrhythmia was the main type of ECG abnormality in all groups. The rates of arrhythmia in noise group, noise dust group, noise welding dust group, noise benzene series group, noise nitrogen oxide group and control group were 16.9%, 16.6%, 27.9%, 17.8%, 13.8% and 6.9%, respectively. The rate of arrhythmia in noise welding dust group was higher than that in noise group(P<0.005). CONCLUSION: The combined effect of noise and benzene series increases the risk of high-frequency hearing loss in workers. The combined effect of noise and welding dust increases the risk of arrhythmia in workers.
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Objective To understand the situation of benzene series compounds pollution inside some Passenger cars in Tangshan and provide data for the formulation of corresponding countermeasures for the prevention and control of the pollution. Methods One hundred and twenty-two cars used for different periods of time were selected from March, 2009 to May, 2009 and the concentrations of benzene,toluene and xylene were determined.At the same time the basic situation (car type, date of manufacture) was investigated with questionnaire. Results The disqualified rate of benzene, toluene, xylene were 14.8%(18/122), 26.2%(32/122) and 20.5%(25/122) respectively. Eighty-one cars did not meet the standard, accounting for 66.4 %(81/122). The median of benzene, toluene, xylene in the cars used within six months were 0.086, 0.900, 0.400 mg/m3 respectively. The exceeded rate of benzene, toluene, xylene inside the cars which were used for not more than six months were 28.6%(10/35), 57.1%(20/35), 60.0%(21/35) respectively. The concentrations of benzene series compounds decreased gradually later on. The concentrations of benzene inside the cars with adsorbent were lower, the concentrations of toluene inside the highgrade cars were higher and the concentrations of xylene inside the cars with leather seats was higher. Conclusion Benzene, toluene, xylene pollution inside cars has been showed in this investigation in Tangshan. The concentrations of benzene series compounds are associated with using time, adsorbent, car grade and the seat material.
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Objective To assess the effects of three way catalytic converter on the health risk of benzene series.Methods After collecting the benzene series(benzene,toluene,xylene) in the air inlet and air outlet of the three way catalytic converser in 100% working loads,their health risk was assessed with the methods of health risk assessment.Results After catalysis,the hazard index of toluene and xylene decreased in all loads,the hazard index and carcinogenesis risk of benzene increased in 100% loads,the chronic long-term hazard index of benzene deceased in 100% loads.Conclusion The three way catalytic converter can change the health risk of benzene series emission by gasoline engine,the carcinogenesis risk of benzene series emission will be increased when the gasoline is treated with the three way catalytic converter.
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Objective To get knowledge of the air pollution situation inside the car caused by the automotive components and decorative materials and the major impacting factors, and to provide the basis for the development of the car air pollution control and countermeasures. Methods Thirty-five cars of different types and ages were selected from January to July 2008. The concentration of benzene series compounds, formaldehyde and TVOC was determined, a survey and analysis of air pollution inside the car was conducted. Results The results showed that the air pollution inside the new cars was serious, with the increase of the using time, the concentration of pollutants reduced. The amount of formaldehyde emission inside the cars was related to the age of the car, the formaldehyde pollution inside the new cars was the most serious in one year. The longer the car was closed, the higher the concentration of pollutants would be. Using perfume or smoking inside the car, car washing or painting could increase the TVOC concentration inside the car. However, after purification treatment, the concentration of air pollutants inside the new cars could significantly decrease. Conclusion The air pollution inside the new cars is so serious, for the health of passengers and drivers, the related standards for the control of the air pollution should be set as soon as possible.