Case study of occupational benzene poisoning and application of GC-MS / 公共卫生与预防医学

Objective To analyze the diagnosis cases of occupational benzene poisoning in gas station industry, and to explore the application of GC-MS technology in occupational disease diagnosis.   Methods The epidemiological method was used to describe and analyze the occupational disease diagnosis of 15 gas station workers , and qualitative screening of occupational hazard factors was performed by GC-MS.   Results All the 15 workers had more than one year's occupation history of oil refueling and unloading.  The clinical manifestations were consistent with the characteristics of chronic benzene poisoning in diagnosis of occupational benzene poisoning.  However, due to lack of evidence of occupational exposure to benzene and incomplete diagnostic data, occupational chronic benzene poisoning was not diagnosed. GC-MS technology was used to screen the occupational hazard factors in the gas station workplace, and benzene, n-pentane, n-hexane and so on were found.  Conclusion GC-MS is recommended for qualitative screening of organic solvents such as benzene when diagnosing occupational diseases for gas station workers , so as to accurately identify occupational hazard factors in workplaces and provide reliable basis for diagnosis of occupational diseases.

Exposição ambiental ao benzeno, parâmetros hematológicos e níveis urinários de ácido trans, trans-mucônico em uma comunidade da região Nordeste do Brasil / Environmental exposure to benzene, hematological parameters, and urinary levels of trans,trans-muconic acid in a community in the Northeast region of Brazil

Resumo Introdução O metabólito do benzeno ácido trans, trans-mucônico (t, t-MA) urinário é considerado bom bioindicador de exposição a níveis de benzeno no ar superiores a 0,50 ppm. Objetivo Determinar níveis urinários de ácido trans, trans-mucônico (t, t-MA) e investigar relação com potenciais fontes de exposição ao benzeno e associação com parâmetros hematológicos. Método Estudo seccional, com 150 moradores de Açailândia, Maranhão, Brasil. Utilizou-se questionário estruturado para caracterização sociodemográfica, ocupacional, dentre outras. Coletaram-se amostras de urina e sangue para determinar níveis de t, t-MA e realização de hemograma. As associações foram exploradas mediante regressão logística e linear múltipla. Resultados O t, t-MA foi detectado em 27% dos participantes, sendo a média da concentração 0,15 mg/g de creatinina. As alterações hematológicas mais frequentes foram bastonetes baixos (41%), eosinofilia (33%) e níveis reduzidos de hemoglobina (19%). Não encontrou-se correlação estatisticamente significativa entre t, t-MA e parâmetros do hemograma. Os fatores que influenciaram de forma significativa a excreção de t, t-MA foram cor da pele, prática regular de atividades de lazer com exposição a solventes orgânicos e consumo de refrigerante e refresco nas últimas 24 horas. Conclusão A população parece não estar exposta a concentrações elevadas de benzeno. Entretanto, o perfil hematológico revelou presença de alterações bioquímicas compatíveis com anemia e comprometimento imunológico.

Abstract Background The urine benzene metabolite trans,trans-muconic (t,t-MA) is considered a good bioindicator of exposure to benzene levels in the air above 0.50 ppm. Objective Determine urinary levels of trans, trans-muconic acid (t,t-MA) and investigate the relationship with potential sources of exposure to benzene and its association with hematological parameters. Method A sectional study was carried out with 150 residents of Açailândia, Maranhão, Brazil. A structured questionnaire was used for sociodemographic and occupational characterization, among others. Urine and blood samples were collected to determine t,t-MA levels and blood counts. Associations were explored using multiple linear and logistic regressions. Results The t,t-MA was detected in 27% of the participants, with an average concentration of 0.15 mg/g creatinine. The most frequent hematological changes were low rods (41%), eosinophilia (33%), and reduced hemoglobin levels (19%). No statistically significant correlation was found between t,t-MA and blood count parameters. The factors that significantly influenced the excretion of t, t-MA were skin color, regular practice of leisure activities with exposure to organic solvents, and consumption of soda and soft drinks in the last 24 hours. Conclusion The population does not appear to be exposed to high concentrations of benzene. However, the hematological profile revealed the presence of biochemical changes compatible with anemia and immunological impairment.

Protective effects of taurine on learning and memory impairment after exposure to formaldehyde and benzene analogues in young rats / 环境与职业医学

Background Formaldehyde and benzene homologues are common environmental pollutants, and their neurotoxicity has aroused widespread concern. Objective To investigate the effect of taurine on cognitive impairment after exposure to formaldehyde and benzene analogues in young rats. Methods Twenty four-week old SD rats were randomly divided into four groups, with six rats in each group: control group (clean air), model group (5 mg·m−3 formaldehyde + 5 mg·m−3 benzene + 10 mg·m−3 toluene + 10 mg·m−3 xylene), low-dose taurine intervention group (5 g·L−1 taurine + mixture of formaldehyde and benzene analogues), and high-dose taurine intervention group (10 g·L−1 taurine + formaldehyde and mixture of benzene analogues), and the exposure was administered by oral and nasal aerosol inhalation for 28 d. At the end of exposure, the learning and memory ability of rats in each group was measured by Morris water maze test. After the behavioral test, the rats were anesthetized and neutralized, and the brain tissue was harvested for histopathological and molecular biological tests. The apoptosis rate of neurons in hippocampal CA1 area was detected by Tunel assay, and the expression levels of apoptosis-related proteins such as caspase 3, bax, and bcl-2 in hippocampal tissue were detected by Western blotting. Results The growth and development of rats in each group were good during inhalation. During the Morris water maze experiment, the escape latencies of rats in the taurine intervention groups were not different from that in the control group (P>0.05) from day 3 to day 5 of training, while the escape latency of rats in the model group was significantly higher than that in the control group (P <0.05). The number of crossing platform and the target quadrant residence time in the high-dose taurine intervention group were not different from those in the control group (P>0.05), while the two variables in the model group and low-dose taurine intervention group were significantly lower than those in the control group (P <0.05). The apoptotic rates of neurons in the hippocampal CA1 area of rats in the control group, model group, and low-dose and high-dose taurine intervention groups were 5.11%, 18.87%, 9.39%, and 4.63%, respectively. The apoptotic rate in the model group was higher than those in the control group and low-dose and high-dose taurine intervention groups (P<0.05). The expression levels of caspase 3, bax, and bcl-2 in the hippocampus of rats in the low-dose and high-dose taurine intervention groups showed no difference compared with the control group (P>0.05). The expression levels of caspase 3 and bax in the model group were higher than those in the control group and low-dose or high-dose taurine intervention groups (P<0.05), and the expression levels of bcl-2 was lower (P<0.05). Conclusion The mixed exposure to formaldehyde and benzene analogues can damage the learning and memory ability of young rats, and increase the apoptosis of neurons in hippocampal CA1 region. Taurine can reverse the damage induced by formaldehyde and benzene analogues.

Analysis of monitoring results of benzene series in Jinshan District of Shanghai from 2016 to 2021 / 上海预防医学

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.

Benzene and Toluene concentration at different Traffic intersection during pre-mid-post winter season, in ambient air of Aligarh and its impact on human health

In current scenario, pollution in environment, is a big problem for all living species at around the world. We know that, Volatile Organic Compounds (VOCs) in presence of sunlight and oxides of nitrogen in atmosphere are considered as precursors for ozone production at the layer of Troposphere. Concentration of Benzene and Toluene (BT) in ambient air was measured near three major traffic sites in the city of Aligarh, India. All air samples were collected using for two times (in a month) during eight hours of normal working period time for in October – December 2020, and January - March 2021. The three selected sites used in this study represent traffic sites ( at Etah Chungi Chauraha, Quarsi Chauraha and Sootmil Chauraha, Aligarh ). In this study, real-time measurements of Benzene and Toluene concentration were performed the programmable compound specific PID detector designed to provide instantaneous exposure monitoring of a specific organic gas. It monitors a specific gas by utilizing a gas separation tube and the photo-ionization detector (PID) with a 9.8 eV gas discharge lamp (range- 50 ppb to 200 ppb) and whole data analyzed by SPSS software. The study the higher concentration 25.32 ?g/m3 of Benzene in the evening shows at site 3 and lower concentration 10.22 ?g/m3 of Benzene shows at site 2 in the morning. The higher concentration 22.22 ?g/m3 in the evening of Toluene shows at site 1 and lower concentration 07.10 ?g/m3 in the evening of Toluene shows at site 2, were observed respectively. Benzene and Toluene were widely used as a solvent in different products and petroleum. Exposure to a mixture of toluene and benzene in air led to an increase in the cytotoxic effect and DNA damage without any further repair and also its chronic effect on human health. The higher concentration of benzene and toluene co-exposure of benzene or toluene in this study. The relevance of these data on interactions for humans exposed at low benzene concentrations can be best assessed only when the mechanism of interaction is understood at a quantitative level and incorporated within a biologically based modelling framework for human health.

Influence of continuous light and benzene exposure on erythrocyte parameters and expression of miRNA-144/451 in mice / 中国职业医学

@#Abstract: Objective To explore the effects of continuous light and benzene exposure on peripheral blood erythrocyte - Methods parameters and expression of miR 144/451 in the bone marrow of mice. This was a 2×2 factorial design. Photoperiod ， ， factor was set as normal and continuous light levels and mice were treated for 12 hours/12 hours light/dark or 24 hours light - respectively. The benzene exposure factor was set as non exposure and exposure levels. Mice were exposed to benzene by static 3 ， inhalation with a mass concentration of 0.0 and 32.5 mg/m for three hours per day five days per week for a total of four weeks. ， ， Specific pathogen free male C57BL/6 J mice were randomly divided into negative control group simple continuous light group - - ， ， simple benzene exposure group and combined exposure group with 12 mice per group. After benzene exposure peripheral ， blood was collected for the detection of erythrocyte parameters in four periods. After the mice were sacrificed the expression of - - - - miR 451a and miR 144 5p was detected by real time fluorescence quantitative polymerase chain reaction in bone marrow Results （ ）， ， tissues. The hematocrit volume HCT mean corpuscular volume mean corpuscular hemoglobin concentration （ ） - MCHC and mean corpuscular hemoglobin in peripheral blood and the relative expression of miR 451a in bone marrow tissue （ P< ） ， were statistically significant only in mice with benzene exposure all 0.05 . Among them the MCHC of benzene exposed （P< ）， （ P< ） - mice increased 0.05 but the other four indexes decreased all 0.05 compared with non benzene exposed mice. In thenegative control group the change of red blood cells count hemoglobin level and HCT in peripheral blood were rhythmical all P < ） ， （ P > ） rhythmical 0.05 . However the indexes above were out of rhythm all rhythmical 0.05 in the simple continuous light group and the - （ P > combined exposure group. The change of hemoglobin level and HCT of peripheral blood were also out of rhythm all rhythmical ） - - 0.05 in the simple benzene exposure group. The relative expression of miR 451a in bone marrow tissues of negative control （ P < ）， - group and simple continuous light group was rhythmical all rhythmical 0.05 while the relative expression of miR 451a in simple - - （ P > ）Conclusion benzene exposure group and combined exposure group was out of rhythm all rhythmical 0.05 . Benzene exposure ， induced changes in erythrocyte parameters of mice are independent effect and its mechanism may be related to the rhythmic - ， expression disorder of miR 451a in bone marrow tissues. Continuous light exposure benzene exposure and their interactions can ， interfere with the circadian rhythm of erythrocyte parameters such as red blood cell count hemoglobin and HCT to some extent.

Actividades económicas, laborales, ambientales y aditivas con exposición a benceno y el desarrollo de leucemia mieloide aguda / Economic activities, occupational, environmental and additive exposures to benzene and the development of acute myeloid leukemia

Introducción: el benceno es un hidrocarburo aromático obtenido por destilación del alquitrán utilizado en gasolineras y como solvente industrial, clasificado como cancerígeno por exposición ocupacional o ambiental. Está relacionado con el desarrollo de leucemia mieloide aguda (LMA) por su absorción principal por vía inhalatoria, y su metabolismo hepático con producción de benzoquinona de alta liposolubilidad que le permite depositarse en la médula ósea y tejido graso. Objetivo: analizar la asociación de las formas de exposición por actividades económicas, oficios, cargos, exposición ambiental y aditiva con el desarrollo de LMA. Materiales y métodos: revisión sistemática de la literatura en las bases de datos Medline, Embase, Lilacs, Cochrane Library, Toxnet y OpenGrey, en inglés y español con los términos benzene, cancer, leukemia, occupational and enviromental exposition. Resultados: la mayoría de los estudios muestran una relación causal entre la exposición a benceno y el desarrollo de LMA, con predominio en ambientes laborales, seguidos de factores ambientales y aditivos como el humo del cigarrillo. Conclusiones: se encontró evidencia de asociación entre la exposición a benceno ocupacional y/o ambiental con el desarrollo de leucemia mieloide aguda, debido a que altera el estrés oxidativo y la desregulación del aryl hidrocarburo generando efectos citogenéticos, mutación genética y alteraciones epigenéticas que se expresan en hematotoxicidad y desarrollo de leucemia.

Introduction: Benzene is an aromatic hydrocarbon obtained by distillation of tar used in gas stations and as an industrial solvent, classified as a carcinogen by occupational and environmental exposure. It is related with the development of acute myeloid leukemia (AML) mainly due to its absorption by inhalation and hepatic metabolism producing highly-lipid soluble benzoquinone allowing it to deposit in bone marrow and fatty tissue. Objective: to analyze the association of forms of exposure including economic activities, type of workplace, environmental and additive exposure with the development of AML. Material and Methods: systematic review of the literature in Medline, Embase, Lilacs, Cochrane Library, Toxnet and OpenGrey databases in English and Spanish, using the terms benzene, cancer, leukemia, occupational and environmental exposure. Results: most studies show a causal relationship between benzene exposure and AML development, predominantly in work settings, followed by environmental factors including additive sources such as cigarette smoke. Conclusions: we found evidence of an association between occupational and/or environmental exposure to benzene and the development of AML, for it alters oxidative stress and aryl hydrocarbon deregulation inducing cytogenetic aberrations, genetic mutations and epigenetic changes expressed as hematotoxicity and leukemia development.

Effect of exposure to low concentrations of benzene on miR-223 and miR-155 expression in peripheral blood lymphocytes / 预防医学

Objective @#To investigate the effect of exposure to low concentrations of benzene on miR-155 and miR-223 expression in peripheral blood lymphocytes among workers with benzene exposure. @*Methods @#A hundred male employees at a risk of exposure to benzene (the exposed group) were randomly sampled from two small metal products manufacturing enterprises and one medium-sized chemical raw material and chemical products manufacturing enterprise in Ningbo City, Zhejiang Province, and 60 age-matched male employees without benzene exposure were randomly selected as the unexposed group. Age, body mass index ( BMI ), smoking status, alcohol consumption, disease history, medication history and routine blood testing results of subjects were collected using a questionnaire survey. The 8-hour time weighted average concentration ( CTWA ) of benzene was measured in the workplace using thermal desorption gas chromatography, and the urine 8-hydroxy-2' deoxyguanosine ( 8-OHdG ) levels were determined using high-performance liquid-chromatography tandem mass spectrometry (HPLC-MS/MS). The miR-155 and miR-223 expression was quantified in peripheral blood lymphocytes using quantitative fluorescent reverse transcription-polymerase chain reaction assay, and the factors affecting miR-155 and miR-223 expression were identified using multivariable logistic regression analysis. @*Results @#The subjects in the exposed group had a mean age of ( 31.17±7.30 ) years, and were exposed to low concentrations of benzene ( CTWA, 0.05 to 0.30 mg/m3 ) , while the subjects in the unexposed group had a mean age of ( 32.52±6.15 ) years. There were no significant differences between the exposed and unexposed groups in terms of age, BMI, proportion of smokers or proportion of alcohol consumers ( P>0.05 ). There was no significant difference in the median relative miR-155 expression between the exposed and unexposed groups ( 0.953 vs. 1.293, P>0.05 ), and lower median relative miR-223 expression was quantified in the exposed group than in the unexposed group ( 0.540 vs. 1.433, P<0.05 ). Multivariable logistic regression analysis revealed that down-regulation of miR-223 expression correlated with exposure to benzene ( OR=2.719, 95%CI: 1.308-5.651 ). @*Conclusion @#Down-regulation of miR-223 expression may be associated with exposure to low concentrations of benzene.

Analysis on the detection of suspected occupational diseases and occupational contraindications for benzene workers in Tianjin / 中华劳动卫生职业病杂志

Objective: To investigate the detection of suspected occupational diseases and occupational contraindications for benzene workers in Tianjin. Methods: In June 2020, the occupational health inspection data of 16113 benzene workers in 514 enterprises with benzene hazards in 16 municipal districts in Tianjin from January to December 2019 were included in the analysis. Enterprise information included the employer's region, economic type, industry classification and enterprise scale. Occupational health inspection data for benzene workers during their on-the-job period included routine inspection indicators and benzene special inspection indicators. Multivariate unconditional logistic regression was used to analyze the relationship between personal general information, occupational history, enterprise information and suspected benzene poisoning and occupational contraindications of benzene workers. Results: There were 16073 benzene workers in the normal group and 24 in the suspected benzene poisoning group. The detection rate of suspected benzene poisoning in females was higher than that in males (χ(2)=8.26, P=0.004) . There was no significant difference in the detection rates of suspected benzene poisoning among different dimensions such as age, length of service, occupational health inspection institution location, employer location, industry classification, economic type, and enterprise scale (P>0.05) . There were 16073 benzene workers in the normal group and 16 in the benzene contraindication group. The detection rate of benzene contraindications for workers in suburban areas where occupational health inspection institutions were located was higher than that in urban areas (χ(2)=9.71, P=0.002) , and there was no significant difference in the detection rates of contraindications for benzene in other dimensions (P>0.05) . Multivariate logistic regression analysis showed that female benzene workers were more likely to detect suspected benzene poisoning (OR=3.53, 95%CI: 1.57-7.94, P=0.002) ; benzene workers who received physical examination in suburban occupational health inspection institutions (OR=5.81, 95%CI: 1.94-17.42, P=0.002) , the employer's area was in the suburbs (OR=9.68, 95%CI: 1.23-76.07, P=0.031) , and female workers (OR=3.07, 95%CI: 1.13-8.37, P=0.028) , it was easier to detect occupational contraindications. Conclusion: Female benzene workers with employers located in the suburbs have a higher risk of detecting occupational contraindications, and women are more likely to detect suspected benzene poisoning. The management of benzene operations in the production environment of enterprises in the suburbs of Tianjin and the occupational health monitoring of female workers should be strengthened.

Analysis of clinical effect of blood purification on acute benzene-based thinner poisoning / 中华劳动卫生职业病杂志

Objective: To investigate the clinical significance of blood purification on changes in serum toxicant concentration and prognosis of acute benzene-based thinner poisoning. Methods: A total of 44 patients with acute benzene-based thinner poisoning admitted to the emergency department of Characteristic Medical Center of Armed Police from August 2013 to August 2020 were collected and divided into a blood purification group (24 cases) and a conventional treatment group (20 cases) , the general data, toxicant concentrations and prognosis of the two groups of patients were analyzed, and logistic regression analysis was performed on the influencing factors of the prognosis to explore the clinical effect of blood purification. Results: The concentration of poisons in the blood purification group at 24 hours after treatment was significantly lower than that in the conventional treatment group (t=6.76, P<0.001) , and the reduction in the concentration of poisons was significantly higher than that in the conventional treatment group (t=3.33, P=0.002) . The overall improvement rate in the blood purification group was 91.7% (22/24) , which was higher than that in the conventional treatment group (60.0%, 12/20) . Logisitic regression analysis showed that blood purification treatment method was the main factor affecting the prognosis of patients (OR=7.605×10(-5), 95%CI: 6.604×10(-8)-0.087, P=0.008) , and the toxic dose was a synergistic effect on the prognosis of patients factor (OR=1.038, 95%CI: 1.008-1.068, P=0.011) . Conclusion: Early blood purification treatment in patients with acute benzene-based thinner poisoning can rapidly reduce blood toxin concentration, avoid disease progression, and ultimately improve patient prognosis.

Investigation and case analysis of an occupational chronic benzene poisoning accident / 中华劳动卫生职业病杂志

This article investigated an occupational chronic benzene poisoning incident that occurred in a sealing material factory in Hebei Province in September 2019, analyzed the clinical data of workers, to explore the causes of occupational chronic benzene poisoning, and summarize the diagnosis and treatment characteristics and treatment outcome. According to GBZ 68-2013 "Diagnosis of Occupational Benzene Poisoning", a total of 12 cases of occupational chronic benzene poisoning were diagnosed among the 20 workers, including 2 cases of occupational chronic mild benzene poisoning, 7 cases of moderate benzene poisoning, and 3 cases of severe benzene poisoning. Both mild and moderate poisoning patients had recovered after treatment. Severely poisoned patients had recovered more slowly, and the white blood cell count was still 2.0×10(9)-3.0×10(9)/L during the 1-year follow-up. This benzene poisoning incident was caused by illegal operations. The responsibility of the employer, the supervision of the administrative agency, and the awareness of personal protection of employees should be strengthened to avoid or reduce the occurrence of poisoning incidents and ensure the health of workers.

Analysis of typical parameters of air quality in Chinese colleges / 中国学校卫生

Objective@#To analyze the current situation and research update on campus air quality in China, and to provide reference for effective campus environment improvement.@*Methods@#The documents of China national knowledge internet (CNKI) from 1980 to 2020 were extracted and the key words related to campus air quality were analyzed by CiteSpace software. Microorganisms, formaldehyde and benzene were selected, data of 200 literatures were classified and sorted out in different functional areas.@*Results@#Studies on campus air quality in China has been increasing gradually since 2004, especially focusing on indoor air, PM 2.5 and benzene series. The primary microorganism in the air environment of Chinese campuses was bacteria with the concentration of 2 309.31 cfu/m 3 . The ranking of the overall load of bacteria in air of different functional areas was consistent with that of microorganisms: living service area > landscape leisure area > public transport area > scientific research and teaching area > administrative office area > sports activity area. The average value of microbial indicators in indoor air of computer room, office area and campus living areas were more likely exceed the standard. The formaldehyde concentration in the computer room and reading room was high. The health of students exposed to formaldehyde and benzene on campus evaluated by using the evaluation model of the U.S. Environmental Protection Agency proved out to be in the safe range.@*Conclusion@#The concentrations of microorganisms, formaldehyde and benzene in campus environment mostly meet the requirements. Further measures need to be taken to reduce microbial concentration and strengthen formaldehyde monitoring and pollution source management in computer room and reading room.

Avaliação da exposição a BTEX em postos de revenda de combustíveis no Rio de Janeiro, Brasil, e os riscos à saúde do trabalhador / Assessment of exposure to BTEX in vehicle filling stations in Rio de Janeiro, Brazil, and risks to workers' health / Evaluación de la exposición a BTEX en puestos de reventa de combustibles, en Río de Janeiro, Brasil, y riesgos para la salud del trabajador

A gasolina é uma mistura complexa de substâncias, dentre elas estão hidrocarbonetos como o benzeno, tolueno, etilbenzeno e xilenos (BTEX), sendo esses compostos emitidos para a atmosfera, com destaque ao benzeno, por ser comprovadamente carcinogênico. Objetivamos avaliar as concentrações de BTEX no ar de postos de revenda de combustíveis no Município do Rio de Janeiro, Brasil, e calcular o risco de câncer associado a estas exposições. Foram realizados dois tipos de amostragem (fixa e móvel) adaptadas da metodologia nº 1.501 do Instituto Nacional de Segurança e Saúde Ocupacional (Estados Unidos), em seis postos de revenda de combustíveis na Zona Oeste da cidade. A amostragem fixa foi feita próxima às bombas de combustível, enquanto a móvel foi realizada através da coleta do ar na zona respiratória dos trabalhadores (frentistas), conforme estes se deslocavam pelo posto. As amostras foram analisadas por cromatografia gasosa com detecção por ionização em chama. Com os resultados das amostragens foram feitos os cálculos de risco à saúde, usando os indicadores Quociente de perigo (HQ) e Risco de câncer (CR), para avaliar os possíveis efeitos não-carcinogênicos e carcinogênicos, respectivamente, nos trabalhadores dos postos de revenda de combustíveis. As concentrações ambientais para a maioria dos compostos BTEX foram abaixo dos limites preconizados, menos para o benzeno, um composto carcinogênico, que apresentou concentrações muito acima dos limites, levando a altos valores de risco de câncer. Os resultados demonstraram que há riscos à saúde dos trabalhadores de postos de revenda de combustíveis, principalmente o risco de desenvolver câncer, devido à exposição excessiva ao benzeno.

Gasoline is a complex mixture of substances, including aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX). These compounds are emitted into the air, with the special relevance of benzene since it is provenly carcinogenic. The study aimed to assess BTEX concentrations in filling stations in the city of Rio de Janeiro, Brazil, and to calculate the cancer risk associated with such exposures. Two types of sampling were performed (stationary and mobile), adapted from methodology n. 1,501 (U.S. National Institute for Occupational Safety and Health) for aromatic hydrocarbons, in six filling stations in the West Zone of Rio de Janeiro. Stationary sampling was done near the fuel pumps, while mobile sampling was done in the breathing zone of the workers (station attendants) as they moved around the station. The samples were analyzed with gas chromatography flame ionization detector. The sampling results were used to calculate the health risk, using the indicators Hazard quotient (HQ) and Cancer risk (CR) to assess the possible non-carcinogenic and carcinogenic effects, respectively, in filling station workers. Environmental concentrations for the most of the BTEX compounds were below the recommended limits, except for benzene, a carcinogenic compound, which displayed concentrations far above the limits, leading to high cancer risk values. The results showed that there are health risks for filling station attendants, especially the risk of developing cancer from excessive exposure to benzene.

La gasolina es una mezcla compleja de sustancias, entre ellas existen hidrocarburos como el benceno, tolueno, etilbenceno y xilenos (BTEX), emitiéndose estos compuestos a la atmósfera, donde se destaca el benceno, al tratarse de un carcinogénico comprobado. Los objetivos fueron evaluar las concentraciones de BTEX en el aire de puestos de reventa de combustibles, en el municipio de Río de Janeiro, Brasil, así como calcular el riesgo de cáncer asociado a estas exposiciones. Se realizaron dos tipos de muestra (fija y movible), adaptadas de la metodología nº 1.501 del Instituto Nacional de Seguridad y Salud Laboral (EE.UU.), en seis puestos de reventa de combustibles de la zona oeste de la ciudad. La muestra fija se realizó cerca de las bombas de combustible, mientras que la móvil se hizo mediante tomas de aire en la zona respiratoria de los trabajadores (de la gasolinera), a medida que estos se desplazaban por el lugar de trabajo. Las muestras se analizaron por cromatografía gaseosa con detección por ionización en llama. Junto a los resultados de las muestras, se realizaron cálculos de riesgo para la salud, usando los indicadores Cociente de peligro (HQ) y Riesgo de cáncer (CR), con el fin de evaluar los posibles efectos no-carcinogénicos y carcinogénicos, respectivamente, en los trabajadores de los puestos de reventa de combustibles. Las concentraciones ambientales para la mayoría de los compuestos BTEX estuvieron por debajo de los limites preconizados, menos en el caso del benceno, un compuesto carcinogénico, que presentó concentraciones muy por encima de los límites, llevando a altos valores de riesgo de cáncer. Los resultados demostraron que existen riesgos para la salud de los trabajadores de puestos de reventa de combustibles, principalmente, riesgo de desarrollar cáncer, debido a la exposición excesiva al benceno.

Occupational hazard analysis of volatile components of oil products on employees in gas stations in the town of Xixiang , Baoan District, Shenzhen / 公共卫生与预防医学

Objective To investigate the health status of employees in Guangdong gas stations and analyze the factors of occupational hazards. Methods According to the records of the provincial comprehensive information system, and the division of administrative regions, a random sampling method was used to detect 22 street gas stations in the town of Xixiang, Baoan District, Shenzhen, with 335 related employees included. The hazardous factors of volatile chemical compositions were analyzed, and the results of occupational health examinations of gas station workers were evaluated. Results The occupational hazards in the volatile organic components of each oil product at 22 gas stations were analyzed, and the results showed that they all met the national standards. The occupational health status was evaluated on all employees in the gas stations in this survey. Most of them did not find any occupational hazards, but the health status of the staff in the duty room was better than that of the staff beside the tanker. Conclusion The gas station workers were at the general occupational hazard risk, but occupational protection also needs to be strengthened. Regular inspection of oil and gas recovery devices is required to improve the airtightness. Regular occupational training should be conducted to further standardize vocational operation.

Exosomes Derived from Hydroquinone-transformed Human Bronchial Epithelial Cells Inhibited Recipient Cell Apoptosis by transferring miR-221 / 生物医学与环境科学（英文）

Objective@#Although benzene is a confirmed environmental carcinogen, the mechanism of its carcinogenicity remains largely unclear. The suggested oncogene, miR-221, is elevated and plays important roles in various tumors, but its role in benzene-induced carcinogenesis remains unknown.@*Methods@#In the present study, we constructed hydroquinone (HQ, a representative metabolite of benzene with biological activity)-transformed malignant cell line (16HBE-t) and analyzed the level of miR-221 in it with qRT-PCR. Exosomes from 16HBE-t cells incubated with or without an miR-221 inhibitor were isolated by ultracentrifugation, characterized by transmission electron microscopy and laser scanning confocal microscope, and then transfected into 16HBE cells. The effects of exosomal miR-221 on apoptosis induced by HQ in recipient cells were determined using flow cytometry.@*Results@#The amount of miR-221 in 16HBE-t was significantly increased compared with controls. When recipient cells ingested exosomes derived from 16HBE-t, miR-221 was increased, and apoptosis induced by HQ was inhibited. Blocking miR-221 in 16HBE-t using an inhibitor did not significantly alter miR-221 or apoptosis in recipient cells.@*Conclusion@#Exosomal miR-221 secreted by 16HBE-t inhibits apoptosis induced by HQ in normal recipient cells.

Occupational Health Risk Assessment of Benzene, Toluene, and Xylene in Shanghai / 生物医学与环境科学（英文）

Objective@#This study was designed to conduct a retrospective and systematic occupational health risk assessment (OHRA) of enterprises that used benzene, toluene, and xylene (BTX) in Shanghai, China.@*Methods@#All data for the study were obtained from 1,705 occupational health examination and evaluation reports from 2013 to 2017, and a semiquantitative model following Chinese OHRA guidelines (GBZ/T 298-2017) was applied for the assessment.@*Results@#The selected enterprises using BTX were mainly involved in manufacturing of products. Using the exposure level method, health risk levels associated with exposure to BTX were classified as medium, negligible, or low. However, the risk levels associated with benzene and toluene were significantly different according to job types, with gluers and inkers exhibiting greater health risks. For the same job type, the health risk levels assessed using the comprehensive index method were higher than those using the exposure level method.@*Conclusion@#Our OHRA reveals that workers who are exposed to BTX still face excessive health risk. Additionally, the risk level varied depending on job categories and exposure to specific chemicals. Therefore, additional control measures recommended by OHRA guidelines are essential to reduce worker exposure levels.

Analysis of surveillance results of key occupational diseases in Nanning City, 2015-2019 / 中国职业医学

OBJECTIVE: To analyze the distribution characteristics of surveillance results of key occupational diseases in Nanning City.METHODS: The occupational health monitoring data of key occupational diseases of Nanning City from 2015 to 2019 were collected using judgment sampling method and analyzed by descriptive epidemiology method. RESULTS: A total of 38 cases of key occupational diseases were reported in Nanning City during the past 5 years.The main diseases were occupational pneumoconiosis and occupational noise-induced deafness(ONID). The rate of occupational health examination was 40.06%, showing an increasing trend with the increase of years(P<0.01). The detection rate of occupational pneumoconiosis was higher than that of ONID(0.19% vs 0.01%, P<0.01). However, the abnormal detection rate of occupational health special examination in noise-exposed workers was higher than that in dust-exposed workers(10.98% vs 0.35%, P<0.01). The detection rate of pneumoconiosis-like changes in dust-exposed workers was the highest in private enterprises(P<0.01). The detection rate of binaural high frequency average hearing threshold ≥40 dB was highest in small and micro enterprises and private enterprises(all P<0.01). The detection rate of blood lead level >400 μg/L was 24.75%, and 98.80% of the abnormal workers were concentrated in medium-sized foreign-funded enterprises. The detection rates of abnormal leukocyte, neutrophil and platelet counts in benzene-exposed workers were 1.17%, 3.21% and 0.26% respectively. CONCLUSION: Among the key occupational disease risk factors in Nanning City, the number of workers exposed to dust and noise is relatively high, which results in serious consequences and harm. But the hazards of lead and benzene cannot be ignored. Emphasis should be placed on strengthening the supervision and management of key occupational diseases in small and medium-sized micro-enterprises and private enterprises.

Analysis of occupational disease, suspected occupational disease and occupational contraindication in a petrochemical enterprise / 中国职业医学

OBJECTIVE: To analyze the diagnosis of occupational disease and the detection status of suspected occupational disease and occupational contraindication in recent years in a petrochemical enterprise. METHODS: The data of new cases of occupational disease reported by a petrochemical enterprise from 2008 to 2019, the cases of suspected occupational disease and occupational contraindication from 2015 to 2019 were collected. The related data was descriptively analyzed. RESULTS: A total of 30 new cases of occupational disease were reported in this petrochemical enterprise from 2008 to 2019. Among them, there were 16 cases of occupational noise deafness, 10 cases of chronic occupational benzene poisoning, 2 cases of occupational leukemia caused by benzene, 1 case of occupational solvent gasoline poisoning and 1 case of occupational pneumoconiosis. Among the 30 cases of occupational diseases, 28 cases(93.3%) were related to benzene and noise exposure, and 19 cases(63.3%) came from the chemical and oil refining divisions. From 2015 to 2019 in this petrochemical enterprise, 24 cases of suspected occupational disease were reported, of which 17(70.8%) suspected cases were diagnosed as occupational disease, and 63 cases of occupational contraindication were reported, including 47(74.6%) cases of occupational contraindication caused by noise. CONCLUSION: Benzene and noise should be taken as the key factors of occupational hazard for prevention and control in the petrochemical enterprises, and control measures should be adopted for special operation links and job posts to control the hidden dangers of benzene and noise that exceeds the standard limits.

Effect of co-exposure of low-level benzene derivatives and noise on hearing loss of workers / 中国职业医学

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.

Alterações biológicas em operadores de bomba de abastecimento expostos ao benzeno: uma revisão sistemática / Biological changes in benzene-exposed supply pump operators: a systematic review

Introdução: O benzeno é um composto proveniente do petróleo, adicionado à gasolina em pequena quantidade para aumentar a octanagem desse combustível. Esse composto está presente nos veículos, por isso a população está exposta à emissão de vapores de gasolina. Contudo, deve-se ter uma atenção especial aos trabalhadores de postos de gasolina, pois esses são submetidos a níveis altos de benzeno, que pode causar desde sintomas por exposição aguda até o desenvolvimento de leucemia pela cronicidade da exposição. Objetivo: Estudar as alterações biológicas pela exposição ao benzeno em operadores de postos de serviços e bombas de abastecimento inflamáveis, analisar os riscos do hidrocarboneto benzeno ao organismo destes trabalhadores e propor a inserção de análise de um novo perfil hematológico, bioquímico e imunológico no exame médico ocupacional destes trabalhadores. Material e Método: Este trabalho consiste em uma revisão sistemática qualitativa da literatura, fundamentada nas recomendações do PRISMA statement, utilizando-se como frase de busca: ("Hidrocarbon*" OR "Benzen") AND ("hematology*") AND ("filling station"). Resultado: Os achados de seis artigos originais foram apresentados em tabela. Conclusões: Estudos complementares devem ser realizados com a finalidade de detectar marcadores que permitam o diagnóstico precoce dos danos hematológicos, bioquímicos e imunológicos provocados pela exposição ao benzeno.

Introduction: Benzene is a petroleum compound, that is added to gasoline in small quantities to increase the octane of this fuel. This compound is present in vehicles, so the population as a whole is exposed to the emission of gasoline vapors. However, special attention should be paid to gas station workers, because they are subjected to high levels of benzene, which can cause from acute exposure symptoms to the development of leukemia due to chronic exposure. Objective: To study the biological changes due to benzene exposure in service station and flammable supply pumps operators, to analyze the risks of benzene to the organism of these workers and to propose the insertion of a new hematological, biochemical and immunological profile in the medical examination occupational of workers. Material and Method: This work consists of a qualitative systematic literature review, based on the recommendations of the PRISMA statement, using as search phrase: ("Hydrocarbon *" OR "Benzen") AND ("hematology *") AND ("filling station"). Results: The findings of six original articles were presented in a table. Conclusions: Complementary studies should be performed to detect markers, that allow the early diagnosis of hematological, biochemical and immunological damage, caused by exposure to benzene.