Benzene Exposure Research Articles

Chronic hematologic manifestations of benzene exposure in fuel dispatchers

Introduction: benzene is an aromatic hydrocarbon considered carcinogenic due to its high toxicity, although in recent years its exposure has decreased, however, it has not been sufficient to prevent complications. Chronic exposure in concentrations greater than or equal to 1 ppm for a period of more than 8 hours a day for 10 constant years or when exposure exceeds 10 ppm for 1 year, there is a risk of developing hematological disorders.Objective: identify chronic hematological manifestations due to exposure to benzene in fuel dispatchers.Methods: a narrative review was carried out, compiling information from January 2000 to November 2022 in scientific databases such as Pubmed, Environmental Pollution, Dialnet, SAGE, Taylor and Francis, Springerlink, Science Direct, Scielo; using key words. Results: hematological manifestations that develop after chronic exposure to benzene at any concentration include lymphoid leukemia, non-Hodgkin's lymphoma, acute myeloid leukemia, myelodysplastic syndrome, chronic myeloid leukemia, multiple myeloma, chronic myeloid leukemia and aplastic anemia.Conclusions: there are various manifestations of chronic exposure to benzene, including chronic lymphatic leukemia, non-Hodgkin's lymphoma, acute or chronic myeloid leukemia, myelodysplastic syndrome and multiple myeloma; therefore, annual medical check-ups and the application of strategies to reduce the time of occupational exposure are recommended in order to diagnose and prevent hematological diseases, since there are currently no prevention regulations to guarantee the wellbeing of dispatchers

Machine learning assessment of white blood cell counts in workers exposed to benzene: a historical cohort study.

To explore the fitting effect of the ARIMA, GM(1,1), and RANSAC model in the changes of white blood cells (WBC) in benzene-exposed workers, and select the optimal model to predict the WBC count of workers. Among 350 employees in an aerospace process manufacturing enterprise in Nanjing, workers with 10years of benzene exposure were selected, and used Excel software to organize the WBC data, and the ARIMA model and RANSAC model were established by R software, and the GM(1, 1) model was established by DPS software, and the magnitude of the mean absolute percentage error (MAPE) of fitting three models to WBC counts was compared. The MAPE based on the ARIMA(2,1,2) model is 6.78%, the MAPE based on the GM(1,1) model is 5.19%, and the MAPE based on the RANSAC model is 6.37%, so the GM( 1,1) model was more suitable for fitting the trend of WBC counts in benzene exposed workers in this study. The GM(1,1) model is suitable for fitting WBC counts in a small sample size and can provide a short-term prediction of WBC counts in benzene-exposed workers and provide basic information for occupational health risk assessment of workers.

610 EMERGING TRIGGERS OF ARRHYTHMIC EVENTS IN REMOTE MONITORED PATIENTS

Abstract Background and aims Worldwide, air pollution is the fourth leading cause of death. Both brief and long-term exposures to air pollution have been associated with marked increases in cardiovascular-related morbidity and mortality. Previous studies have focused on the short-term influence of particulate pollutants on ventricular arrhythmia (VA) development, primarily expressed as 24-hour Holter ECG monitoring arrhythmic burden or as presentation as life-threatening ventricular arrhythmias. The aim of our study was to investigate the association between air pollutant exposure and VA burden in remotely-monitored patients. Methods We enrolled retrospectively 86 patients carriers of implantable cardioverter-defibrillators (ICD), loop recorders (ILR) or pacemaker devices with remote monitoring via CarelinkTM Medtronic or Merlin.netTM PCN Abbott softwares. Intracavitary and ILR tracings were reviewed by EP personnel at our centre to define VA burden and the number of appropriate shocks and ATPs occurred in 2021. Demographic and clinical characteristics (e.g. cardiovascular history, ejection fraction, smoking, antiarrhythmic drugs (AADs)) were collected through telephone interviews. Each patient's residential and working address were used to obtain information on pollutant exposure in the years 2017-2021 in terms of annual mean concentrations of PM10, PM2.5, ozone, sulfur dioxide, carbon dioxide, carbon monoxide and benzene, as determined by European Environmental Agency air quality reports. The primary endpoint was a composite of ventricular fibrillation, sustained and nonsustained ventricular tachycardia, appropriate ATP or shocks in patients with various levels of air pollutants exposure. Results Of 86 patients (58 male, mean age 63.2±18.7 years) enrolled in this study, 44 (51.6%) had received an ICD, 32 of whom (37.2%) with a primary prevention indication. 31 patients (36.1%) had been receiving at least one AAD. History of coronary artery disease (CAD) was present in one third of the study population and baseline mean EF was 49.8±13.8%. VA events occurred in 17 patients (19.8%), all with a significantly lower baseline EF (40.3±12.2% vs 51.5±13.5% p=0.005). Average mean values of benzene concentration in the previous 4 years were significantly higher in patients suffering from a VA event (1.64±0.82 μg/m3 vs 1.12±0.48 μg/m3, p=0.001), as were PM2.5 values (11.64±1.98 vs 10.74±1.28 μg/m3, p=0.023). A weak but positive correlation was found between median PM2.5 concentration, benzene and VAs (p=0.023, p=0.001 respectively). A multivariate regression model was built, including long-term exposure to benzene and PM2.5 and baseline EF, and it would explain 29.8% of the variance in VAs, correctly classifying 78.1% of cases. Conclusions This study was the first to evaluate the relationship between long-term exposure to a wide array of air pollutants and VAs in a European population. In our sample, we found a weak but significant correlation between a higher chronic exposure to benzene and recorded VA events. Possible mechanisms may include oxidative stress and a direct, nonspecific membrane action due to benzene lipophilic properties. Hence, we highlighted the possible role of outdoor benzene exposure in ventricular arrhythmogenesis for the first time, a finding that requires validation through subsequent studies aimed at elucidating the role of air pollution as a ubiquitous, potentially modifiable, population-based risk factor.

The prediction of occupational health risks of benzene in the printing industry through multiple occupational health risk assessment models.

Benzene poisoning is a common occupational poisoning event in the printing industries. Up to now there is still a lack of research data on risk assessment of benzene operations in enclosed workshops. It is crucial to assess the risk level of these positions and put forward effective measures and suggestions. The information of selected companies and air samples were collected through on-site investigation, data collation and sample testing were carried out according to the requirements of Chinese standards. The Control of Substances Hazardous to Health (COSHH) Essential, the EPA non-carcinogenic risk assessment model, the Singapore exposure index method and the Chinese semi-quantitative risk assessment models were used to assess the risks of benzene. The exposed groups all worked more than 8 h per day, and the cleaning, pasting, and packaging groups used general ventilation rather than local ventilation. 28.6% of the printing group and 16.7% of the pasting group had benzene concentrations that exceeded the permissible concentration-time weighted average (PC-TWA) in China. Over 60.0% of the work groups were evaluated at high risk and over 20% of the work groups were evaluated at high cancer risk by the risk assessment models. The Chinese exposure index method and the synthesis index method may have a stronger practicability. The printing and pasting groups may have a higher risk for benzene exposure. It is necessary to increase protective measures and strengthen occupational hygiene management to reduce risks.

Genus unclassified_Muribaculaceae and microbiota-derived butyrate and indole-3-propionic acid are involved in benzene-induced hematopoietic injury in mice

Benzene is a group I carcinogen determined by IARC. The prevalence of benzene in occupational and general environments increases the risk of acute myeloid leukemia (AML) among workers and childhood leukemia. However, the mechanism of hematotoxicity induced by benzene remains unclear. Recently, the gut microbiota has been regarded as a pivotal part of normal and malignant hematopoiesis. Therefore, in this study, we explored the function of gut microbiota in hematopoietic injury induced by benzene by 16S rRNA sequencing. We found that benzene exposure caused bone marrow damage, hematopoietic stem and progenitor cells (HSPCs) dysfunction, and peripheral blood cell reduction. Moreover, intestinal barrier damage and gut microbiota dysbiosis were also observed in benzene-exposed mice. Interestingly, two gut flora, Lachnospiraceae_NK4A136_group and unclassified_Muribaculaceae, were significantly up-regulated and associated with hematopoietic indicators, suggesting that gut-host crosstalk might mediate benzene hematotoxicity. Microbiota-derived metabolites, such as short-chain fatty acids (SCFAs), bile acids, and tryptophan metabolites, are the primary mediators of the gut-host crosstalk. Therefore, we conducted absolute quantitative metabolomics to investigate the impact of benzene exposure on these metabolites in mice. The results showed that the concentration of SCFA butyrate, tryptophan metabolites kynurenine, and Indole-3-propionic acid (IPA) were significantly altered after benzene exposure. However, no difference was found in bile acids. Significant correlations were found between altered metabolites and hematopoietic indicators. We then investigated the flora that derived these metabolites. Lachnospiraceae_NK4A136_group and unclassified_Muribaculaceae were enriched in the butyrate metabolism and tryptophan metabolism pathways. Correlation analysis further suggested that unclassified_Muribaculaceae was positively associated with butyrate (r = 0.588, P < 0.05) and IPA (r = 0.59, P < 0.05). The above results demonstrated that unclassified_Muribaculaceae and microbiota-derived butyrate and IPA were involved in hematopoietic toxicity caused by benzene. This study provides insight into gut microbiota-derived metabolites-host crosstalk in benzene hematopoietic toxicity.

Explication on distribution patterns of volatile organic compounds in petro-chemistry and oil refineries of China using a species-transport model and health risk assessment

Volatile organic compounds (VOCs) from industrial emissions have attracted great attention due to their negative effects on human, but there is lack of deterministic air quality model for VOC emissions. In this study, airborne VOCs from a typical petrochemical and oil refinery region, Lanzhou, Gansu province of China, were on-site measured. The regional pollution patterns were investigated using a species transport model and the health risks were evaluated. The spatial distribution of VOCs showed that 87.5 % of the airborne VOCs were benzene, toluene, ethylbenzene, and xylene having higher concentration (146 μg/m3) in the north direction oil refinery industrial areas. The concentrations of toluene and benzene were as high as 41.5 and 33.3 μg/m3 in the 4 km2 area away from the petrochemical emission source, respectively, and the concentration of o−/m + p-xylene was up to 79.7 μg/m3. Based on the measured concentration data, the numerical results showed that the accumulation of high concentration of VOC species by mass transfer in the region is related to the atmospheric diffusion driven by downward-moving air over the valley areas. Non-carcinogenic risk assessments showed that airborne benzene exposure had acceptable hazard quotient of 0.185 for adults, which was 1.8 times of children's (0.102), whereas it was found that a high carcinogenic risk (>10−4) from benzene in several sampling sites and diffuse distance become significant for carcinogenic risk. This study verified the effectiveness of VOC atmospheric diffusion model through a large number of on-site monitoring data, providing data support for model-based risk assessment.

Shikonin targets to m6A-modified oxidative damage pathway to alleviate benzene-induced testicular injury.

Benzene exposure causes reproductive toxicity through oxidative damage. However, the specific mechanisms of benzene-induced testicular damage and the potential therapeutic drugs remain poorly understood. In the present study, C57BL/6J mice have been exposed to 0 and 150mg/kg benzene for four weeks. Then, we found that benzene exposure induced testicular damage in mice, mainly manifested by decreased testicular coefficients, abnormal semen parameters and HE-stained intraepithelial vacuolation. On the mechanism, benzene exposure activated Kelch Like ECH Associated Protein 1/Nuclear factor-erythroid 2 related factor 2 (Keap1/Nrf2) and NF-κB signaling pathway, then promoted apoptosis and inflammatory responses in testes. In vitro, massive reactive oxygen species (ROS) production and a large number of apoptotic cells were observed after 1,4-BQ treatment of GC-2cells. Furthermore, benzene altered the expression of three important RNA methylation modulator genes, methyltransferase-like 3 (Mettl3), AlkB homolog 5 (Alkbh5) and YTH domain containing 2 (Ythdc2). Moreover, both m6A modification and mRNA levels of NF-κB increased with benzene exposure. Inspiringly, shikonin alleviated benzene-induced male reproductive damage by targeting m6A-modified NF-κB in mice testes. Our study provides new insights into molecular mechanisms of RNA m6A modification in benzene-induced reproductive injury and directions to find potential drugs for the treatment of male infertility.

Emotional and behavioral attitudes of Tunisian youth towards childhood leukemia: health education and primary prevention in perspective

BackgroundGiven the increasing blood cancer incidence in Tunisia and recent discoveries proving the involvement of environmental factors, this study examined the environmental health literacy (EHL) of Tunisian secondary school students concerning not only this disease, but also their emotional and behavioral attitudes towards leukemia risks.MethodsA cross-sectional survey was conducted among Tunisian youths (N = 372, 16–20 years; 68% females, 32% males). Data collection took place in four representative public secondary schools in the North, Center, and South of Tunisia. Students completed a paper and pencil questionnaire and described their EHL level of blood cancer, as well as their attitudes and interests in this disease. The statistical software (SPSS, v.25.0) was used to analyze the data collected.ResultsThe results indicated low EHL levels of leukemia. Most youths failed to identify all the leukemogenic (except tobacco and pollution) and non- leukemogenic risk factors. Pesticide use and exposure to low frequency electromagnetic radiation were not considered risk factors. Proximity to heavy-traffic roads and benzene exposure were not perceived by youth as risk factors. Despite these low levels, most participants were interested in having more information about leukemia and cancers in general.ConclusionThis investigation shows a lack of knowledge about leukemia. Low EHL levels will incite educational actors and curriculum designers to optimize content and innovate ICT adapted to this environmental health challenge.

Assessing the effect of BTEX on blood and spirometry parameters staff in a petroleum refinery.

This study aimed to investigate the impact of BTEX compound on blood and spirometry parameters of staff in the Abadan petroleum refinery (Iran). In 80 staff was examined in terms of BTEX exposure (40 exposed and 40 non-exposed). In this study, the air sampling was carried out according to the NIOSH 1,501 method and an automated hematology analyzer was used to analyze all blood samples to evaluate blood parameters and using a Micro Direct automated computerized spirometer. Spss20 software was used to interpret the performance. According to the obtained results, total BTEX concentrations with the recommended standard level showed that, toluene, ethylbenzene, and xylenes, concentrations in Abadan Oil Refining Company Workers' breathing zone were lower than the TLV-TWA recommended by ACGIH. However, the average concentration of benzene was higher than the allowable limit. Therefore, in this study the effect of benzene on the blood and respiratory parameters of the workers was evaluated, the comparison of the blood and respiratory parameters between the groups of exposed and unexposed workers did not reveal any statistical difference between the groups (p > 0.001). The results showed no statistically significant connection between mean blood and spirometry parameters and benzene exposure. Also, based on results the effect of benzene problems needs to be prevented in employees with adequate engineering and management controls and periodic inspection.

Effects of Benzene: Hematological and Hypersensitivity Manifestations in Resident Living in Oil Refinery Areas.

Literature is teeming with publications on industrial pollution. Over the decades, the main industrial pollutants and their effects on human health have been widely framed. Among the various compounds involved, benzene plays a leading role in the onset of specific diseases. Two systems are mainly affected by the adverse health effects of benzene exposure, both acute and chronic: the respiratory and hematopoietic systems. The most suitable population targets for a proper damage assessment on these systems are oil refinery workers and residents near refining plants. Our work fits into this area of interest with the aim of reviewing the most relevant cases published in the literature related to the impairment of the aforementioned systems following benzene exposure. We perform an initial debate between the two clinical branches that see a high epidemiological expression in this slice of the population examined: residents near petroleum refinery areas worldwide. In addition, the discussion expands on highlighting the main immunological implications of benzene exposure, finding a common pathophysiological denominator in inflammation, oxidative stress, and DNA damage, thus helping to set the basis for an increasingly detailed characterization aimed at identifying common molecular patterns between the two clinical fields discussed.

ROS-directed activation of Toll/NF-κB in the hematopoietic niche triggers benzene-induced emergency hematopoiesis.

Hematopoietic stem cells/progenitor cells (HSC/HPCs) orchestrate the hematopoietic process, effectively regulated by the hematopoietic niche under normal and stressed conditions. The hematopoietic niche provides various soluble factors which influence the differentiation and self-renewal of HSC/HSPs. Unceasing differentiation/proliferation/high metabolic activity of HSC/HPCs makes them susceptible to damage by environmental toxicants like benzene. Oxidative stress, epigenetic modifications, and DNA damage in the HSC/HPCs are the key factors of benzene-induced hematopoietic injury. However, the role of the hematopoietic niche in benzene-induced hematopoietic injury/response is still void. Therefore, the current study aims to unravel the role of the hematopoietic niche in benzene-induced hematotoxicity using a genetically tractable model, Drosophila melanogaster. The lymph gland is a dedicated hematopoietic organ in Drosophila larvae. A group of 30-45cells called the posterior signaling center (PSC) in the lymph gland acts as a niche that regulates Drosophila HSC/HPCs maintenance. Benzene exposure to Drosophila larvae (48h) resulted in aberrant hemocyte production, especially hyper-differentiation of lamellocytes followed by premature lymph gland dispersal and reduced adult emergence upon developmental exposure. Subsequent genetic experiments revealed that benzene-induced lamellocyte production and premature lymph gland dispersal were PSC mediated. The genetic experiments further showed that benzene generates Dual oxidase (Duox)-dependent Reactive Oxygen Species (ROS) in the PSC, activating Toll/NF-κB signaling, which is essential for the aberrant hemocyte production, lymph gland dispersal, and larval survival. Together, the study establishes a functional perspective of the hematopoietic niche in a benzene-induced hematopoietic emergency in a genetic model, Drosophila, which might be relevant to higher organisms.

Using Urinary Biomarkers to Estimate the Benzene Exposure Levels in Individuals Exposed to Benzene

Urinary benzene metabolites trans, trans-muconic acid (t, t-MA), and S-phenyl mercapturic acid (S-PMA) are often used as biomarkers of internal exposure to benzene. However, there are few reports on using urinary benzene metabolites to estimate airborne benzene concentrations in individuals exposed to benzene. In this study, t, t-MA, and S-PMA were analyzed by UPLC-MS/MS, and a simple pharmacokinetic model was used to calculate the daily intake (DI) of benzene based on the levels of urinary t, t-MA, and S-PMA in occupational individuals. The back-calculated airborne benzene levels (BCABL) were obtained from the DI of benzene. Among the exposed subjects (n = 84), the median BCABL (3.67 mg/m3) based on t, t-MA was very close to the median level of measured airborne benzene (3.27 mg/m3, p = 0.171), and there was no effect of smoking or dietary habits on t, t-MA-based BCABL. In the control subjects (n = 49), the levels of measured airborne benzene were all below the quantitation limit (0.024 mg/m3), and the BCABL (0.002-0.25 mg/m3) calculated by S-PMA was close to this background level. Our study suggests that the t, t-MA-based BCABL can reflect the actual airborne benzene level in a range of 1.10-86.91 mg/m3 and that the S-PMA-based BCABL is more reliable for non-professional benzene exposure.

Benzene Exposure From Selected Work Tasks on Offshore Petroleum Installations on the Norwegian Continental Shelf, 2002-2018.

Work on offshore petroleum installations may cause exposure to benzene. Benzene is a carcinogenic agent, and exposure among workers should be as low as reasonably practicable. We aimed to assess short-term (less than 60 min) benzene exposure from the most frequent work tasks on offshore installations on the Norwegian continental shelf and identify determinants of exposure. In addition, we aimed to assess the time trend in task-based benzene measurements from 2002 to 2018. The study included 763 task-based measurements with a sampling duration of less than 60 min, collected on 28 offshore installations from 2002 to 2018. The measurements were categorized into 10 different tasks. Multilevel mixed-effect Tobit regression models were developed for two tasks: sampling and disassembling/assembling equipment. Benzene source, season, indoors or outdoors, design of process area, year of production start, sampling method, and work operation were considered as potential determinants for benzene exposure in the models. The overall geometric mean (GM) benzene exposure was 0.02 ppm (95% confidence intervals 95%(CI: 0.01-0.04). The pipeline inspection gauge (PIG) operation task was associated with the highest exposure, with a GM of 0.33 ppm, followed by work on flotation cells, disassembling/assembling, and sampling, with GMs of 0.16, 0.04, and 0.01 ppm, respectively. Significant determinants for the disassembling/assembling task were work operation (changing or recertifying valves, changing or cleaning filters, and breaking pipes) and benzene source. For sampling, the benzene source was a significant determinant. Overall, the task-based benzene exposure declined annually by 10.2% (CI 95%: -17.4 to -2.4%) from 2002 to 2018. The PIG operation task was associated with the highest exposure out of the ten tasks, followed by work on flotation cells and when performing disassembling/assembling of equipment. The exposure was associated with the type of benzene source that was worked on. Despite the decline in task-based exposure in 2002-2018, technical measures should still be considered in order to reduce the exposure.

Association of metabolites of benzene and toluene with lipid profiles in Korean adults: Korean National Environmental Health Survey (2015–2017)

BackgroundEnvironmental exposure to benzene and toluene is a suspected risk factor for metabolic disorders among the general adult population. However, the effects of benzene and toluene on blood lipid profiles remain unclear. In this study, we investigated the association between urinary blood lipid profiles and metabolites of benzene and toluene in Korean adults.MethodsWe analyzed the data of 3,423 adults from the Korean National Environmental Health Survey Cycle 3 (2015–2017). We used urinary trans,trans-muconic acid (ttMA) as a biomarker of benzene exposure, and urinary benzylmercapturic acid (BMA) as an indicator of toluene exposure. Multivariate logistic regression analyses were performed to explore the association between blood lipid profiles and urinary metabolites of benzene and toluene. Additionally, we examined the linear relationship and urinary metabolites of benzene and toluene between lipoprotein ratios using multivariate regression analyses.ResultsAfter adjusting for covariates, the fourth quartile (Q4) of ttMA [odds ratio (OR) (95% confidence interval, CI = 1.599 (1.231, 2.077)] and Q3 of BMA [OR (95% CI) = 1.579 (1.129, 2.208)] were associated with an increased risk of hypertriglyceridemia. However, the Q4 of urinary ttMA [OR (95% CI) = 0.654 (0.446, 0.961)] and Q3 of urinary BMA [OR (95% CI) = 0.619 (0.430, 0.889)] decreased the risk of a high level of low-density lipoprotein cholesterol (LDL-C). Higher urinary ttMA levels were positively associated with the ratio of triglycerides to high-density lipoproteins [Q4 compared to Q1: β = 0.11, 95% CI: (0.02, 0.20)]. Higher urinary metabolite levels were negatively associated with the ratio of low-density lipoprotein to high-density lipoprotein [Q4 of ttMA compared to reference: β = -0.06, 95% CI: (-0.11, -0.01); Q4 of BMA compared to reference: β = -0.13, 95% CI: (-0.19, -0.08)].ConclusionBenzene and toluene metabolites were significantly and positively associated with hypertriglyceridemia. However, urinary ttMA and BMA levels were negatively associated with high LDL-C levels. These findings suggest that environmental exposure to benzene and toluene disrupts lipid metabolism in humans.

Health Risk from Exposure to Benzene: Study in Oil Industry Workers

The purpose of this study was to analyze the health risks of benzene exposure, on human health, especially for workers/employees engaged in the oil industry. To assess the health effects of benzene on workers, it was obtained from health data of workers exposed to benzene in the work environment. Acute exposure (14 days), moderate exposure (15-364 days) and chronic exposure (365 days) are workplaces where benzene exposure is below the Minimum Risk Level (MRL) value of inhaled benzene exposure that is reduced by ATSDR by acute, moderate and chronic exposure, respectively, to benzene. The threshold value of physical and chemical variables in the workplace (1.59 mg/m3) is also set by the Regulation. ATSDR-reduced exposure to toluene (7.6 mg/m3) is below the MRL for chronic inhalation exposure, while acute exposure (3.8 mg/m3) is well below the MRL for chronic inhalation exposure. Symptoms of headache, weariness, and respiratory irritation can be caused by Benzene exposure that exceeds the threshold value and biological exposure index. blood-forming cells and bone marrow dysfunction as well as neurological or reproductive system disorders. After conducting a risk analysis, an overall picture of the risks will be obtained. The results of risk analysis can be qualitative or quantitative depending on the technique or method used. Risk analysis will also provide an overview of the level of risk from various potential hazards that exist.

Occupational Exposures and Health Risks of Benzene, Toluene, and Xylenes (BTX) in Automobile Repair Industry in Beijing City, China.

This study aimed to evaluate the occupational health risks of benzene, toluene, and xylenes (BTX) exposure in the automobile repair industry in Beijing city in China. The concentrations of BTX were monitored at 140 operating positions of 51 randomly selected automobile repair enterprises in 2018. Samples analysis showed that all monitoring concentrations were not higher than the occupational exposure limits. The long-term exposure concentration ranges of benzene, toluene, and xylenes were 0.1 to 0.3, 0.1 to 49.7, and 0.2 to 49.5 mg/m3, respectively. The short-term exposure concentration ranges of benzene, toluene, and xylenes were 0.1 to 0.3, 0.1 to 98.7, and 0.2 to 100.0 mg/m3, respectively. But assessment results revealed unneglectable occupational health risks, especially the combined health risks of BTX exposure. Thereafter, effective control and improvement measures were put forward, including strengthening the management of the production, sale, and use of vehicle paints and coatings; improving ventilation; and implementing hierarchical management measures for occupational health risks.

Let-7e-5p, a promising novel biomarker for benzene toxicity, is involved in benzene-induced hematopoietic toxicity through targeting caspase-3 and p21

Benzene is a common industrial chemical and environmental pollutant. However, the mechanism of hematotoxicity caused by exposure to low doses of benzene is unknown. Let-7e-5p pathway regulatory networks were constructed by bioinformatics analysis using a benzene-induced aplastic anemia (BIAA) mouse model. The MTT assay, EdU staining, flow cytometric analysis, dual luciferase reporter gene assay, and RIP assay were utilized to evaluate the effects of benzoquinone (1,4-BQ) on let-7e-5p pathway. This study consisted of 159 workers with a history of low-level benzene exposure and 159 workers with no history of benzene exposure. After the confounding factors were identified, the associations between let-7e-5p expression and hematotoxicity were assessed by multiple linear regression. Furthermore, we used four machine learning algorithms (decision trees, neural network, Bayesian network, and support vector machines) to construct a predictive model for detecting benzene-causing hematotoxicity in workers. In this study, compared with respective controls, let-7e-5p expression was decreased in BIAA mice and benzene-exposed workers. After 1,4-BQ exposure, let-7e-5p overexpression negatively regulated caspase-3 and p21 expression, protected cells from apoptosis, and facilitated cell proliferation. RIP assays, and dual luciferase reporter gene assays confirmed that let-7e-5p could target p21 and caspase-3 and regulate the cell cycle and apoptosis. The support vector machines classifier achieved the best prediction of benzene-induced hematotoxicity (prediction accuracy = 88.27, AUC = 0.83) by statistically characterizing the internal dose of benzene exposure and the oxidative stress index, as well as the expression levels of let-7e-5p pathway-related genes in benzene-exposed workers. Let-7e-5p may be a potential therapeutic target of benzene-induced hematotoxicity, provide a basis for evaluating the health hazards of long-term and low-dose benzene exposure in workers, and supply a reference for revising occupational health standards.

Study of Parental Occupational Exposures to Solvents and Risk of Autism Spectrum Disorder in Offspring

BACKGROUND AND AIM: Solvents can accumulate in fat and later metabolize during pregnancy. Additionally, these toxicants could lead to germline mutations. We investigated associations between multiple parental occupational solvent exposures and odds of autism spectrum disorder (ASD) diagnosis in offspring. METHODS: Using population-based data from the Danish National Patient Registry, we identified a subset of ASD cases from 1982 to 2016 and 1:100 sex and birth-year matched controls obtained from the Central Population Register. We determined parental occupation history from age 16 years through 6 months post-childbirth from the Danish Pension Fund and estimated cumulative benzene, methylcyclohexane, toluene, trichloroethylene, perchloroethylene, and 1,1,1-trichloroethane exposure for mothers and fathers based on job exposure matrices (JEMs). Conditional logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for exposures one year prior to conception and during pregnancy. RESULTS: In analysis of data from 1898 people with ASD and 141,702 without ASD, there were no observed associations between maternal solvent exposures during pregnancy and risk of ASD in offspring. However, analysis for maternal benzene exposure one year prior to conception revealed higher adjusted odds for those with any exposure (aOR=1.55; 95% CI 1.02, 2.37). Additionally, although there were no significant associations between paternal solvent exposures during pregnancy and ASD risk, there were significantly increased odds of ASD in offspring whose fathers were exposed to benzene (aOR=3.07; 95% CI 1.72, 5.46) and toluene (aOR=1.66; 95% CI 1.05, 2.62) one year before conception. CONCLUSIONS: Although previous studies have suggested parental solvent exposure during pregnancy can contribute to pathogenesis of ASD, our findings suggest that risk may be increased through exposures prior to conception. However, unavoidable non-differential misclassification from the use of JEMs may have masked truly increased risk during pregnancy.

Early hematopoietic injury triggered by benzene characterized with inhibition of erythrocyte differentiation involving the mollicutes_RF39-derived citrulline.

Benzene poisoning is a common adverse blood outcome in occupational workers, manifested by hematopoietic dysfunction. However, the specific phenotype and its mechanisms of early hematopoietic toxicity caused by benzene remain unclear. After 15 days of exposure, the WBC levels were not significantly altered in benzene-exposed mice. However, the level of red blood cells (RBC) showed a significant decrease, and it was significantly and negatively correlated with urinary S-phenylmercapturic acid (SPMA). Notably, 5mg/kg benzene exposure significantly inhibited the renewal capacity and the number of colony formation of hematopoietic stem progenitor cells in mice, especially erythrocyte differentiation. These results suggested that the early hematopoietic toxicity phenotype caused by benzene was dominated by inhibition of erythroid differentiation rather than WBC-related inflammation. To further understand the underlying mechanisms of benzene-induced early hematopoietic toxicity, 16S rRNA sequencing and plasma metabolites analysis were conducted to investigate the impact of benzene exposure for 15 days on microbial composition and metabolic profile of mice. We found that short-term benzene exposure induced disturbances in gut microbiota and metabolism. The relative abundance of Mollicutes_RF39 at order levels was significantly reduced in benzene-exposed mice and was strongly correlated with hematopoietic indicators and urinary benzene markers. Interestingly, Mollicutes_RF39 might disturb the levels of eight metabolites, whereas Citrulline was highly linked to Mollicutes_RF39 (r=0.862, P=0.000). Consequently, Mollicutes_RF39-derived Citrulline might be the key regulator of early hematopoietic injury induced by benzene exposure. These findings promote the understanding of early hematotoxicity phenotypes and provide new perspectives on the underlying mechanisms of benzene-induced hematotoxicity.

Indoor exposure levels and risk assessment of volatile organic compounds in residences, schools, and offices in China from 2000 to 2021: A systematic review.

The last two decades have witnessed rapid urbanization and economic growth accompanied by severe indoor air pollution of volatile organic compounds (VOCs) in China. However, indoor VOC pollution across China has not been well characterized and documented. This study is a systematic review of field measurements of eight target VOCs (benzene, toluene, xylenes, acetaldehyde, p-dichlorobenzene, butadiene, trichloroethylene, and tetrachloroethylene) in residences, offices, and schools in China from 2000 to 2021. The results show that indoor pollution of benzene, toluene, and xylenes has been more serious in China than in other countries. Spatiotemporal distribution shows lower indoor VOC levels in east and south-east regions and a declining trend from 2000 to 2021. Moving into a dwelling more than 1 year after decoration and improving ventilation could significantly reduce exposure to indoor VOCs. Reducing benzene exposure is urgently needed because it is associated with greater health risks (4.5 × 10-4 for lifetime cancer risk and 8.3 for hazard quotient) than any other VOCs. The present study enriches the database of indoor VOC levels and provides scientific evidence for improving national indoor air quality standards as well as estimating the attributable disease burden caused by VOCs in China.