Environmental and Health Effects of Benzene Exposure among Egyptian Taxi Drivers

Blood lead concentrations in exposed forecourt attendants and taxi drivers in parts of South Africa

BACKGROUND

Leaded fuel was banned in South Africa in 2006, in order to improve human health and reduce environmental pollution. Lead (Pb) has been suggested to contribute to the development of neurodegenerative disorders, and the role of respiratory exposure to Pb from petrol fumes should not be neglected in this context. In addition to Pb, petrol contains various harmful chemicals including other neurotoxic metals and hydrocarbons.

OBJECTIVES AND METHODS

Here, we investigated concentrations of Pb and other metals in blood from petrol station forecourt attendants (n = 38), taxi drivers (n = 21), and unexposed controls (n = 36). Taxi drivers and forecourt attendants were divided into three groups each, based on number of years worked. A questionnaire was designed to investigate the health status of the participants. Blood samples were collected by medical professionals and analyzed for metal concentrations by ICP-MS.

RESULTS

A positive correlation between number of years worked and Pb blood concentrations was found. The highest Pb concentration (60.2 µg/L) was observed in a forecourt attendant who had worked 11-20 years, and the average Pb concentration in this group (24.5 µg/L) was significantly (p < 0.05) higher than in forecourt attendants who had worked 2-5 years (10.4 µg/L). Some individuals had elevated concentrations of manganese, arsenic, cadmium, chromium and cobalt, yet not significantly elevated at the group level. The blood levels of arsenic appeared to be related to smoking. Mood swings, dizziness, headaches and tiredness were reported by the workers.

CONCLUSION

Blood Pb concentrations in petrol station forecourt attendants and taxi drivers exposed to leaded petrol are elevated and correlate to exposure time. A health monitoring program should be erected for all individuals working in these industries, and preventive measures should be implemented to eliminate metal exposure from petrol.

Analysis of self-renewing and differentiation-related microRNAs and transcription factors in multilineage mouse hematopoietic stem/progenitor cells induced by 1,4-benzoquinone

Background

HSPCs are targets for benzene-induced hematotoxicity and leukemogenesis. However, benzene toxicity targeting microRNAs (miRNAs) and transcription factors (TF) that are involve in regulating self-renewing and differentiation of HSPCs comprising of different hematopoietic lineages remains poorly understood. In this study, the effect of a benzene metabolite, 1,4-benzoquinone (1,4-BQ) exposure, in HSPCs focusing on the self-renewing (miRNAs: miR-196b and miR-29a; TF: HoxB4, Bmi-1) and differentiation (miRNAs: miR-181a, TF: GATA3) pathways were investigated.

Methods

Freshly isolated mouse BM cells were initially exposed to 1,4-BQ at 1.25 to 5 µM for 24 h, followed by miRNAs and TF studies in BM cells. Then, the miRNAs expression was further evaluated in HSPCs of different lineages comprised of myeloid, erythroid and pre-B lymphoid progenitors following 7-14 days of colony forming unit (CFU) assay.

Results

Exposure to 1,4-BQ in BM cells significantly (p < 0.05) reduced the miR-196b (2.5 and 5 µM), miR-181a (1.25, 2.5 and 5 µM) and miR-29a (1.25 µM) along with upregulation of miR-29a at 2.5 µM. Meanwhile, 1,4-BQ exposure in HSPCs significantly increased the miR-196b expression level (p < 0.05) only in myeloid and pre-B lymphoid progenitors at 2.5 and 5 µM. Significant (p < 0.05) reduction in expression of miR-181a in myeloid (1.25 µM), erythroid (5 µM) progenitors along with miR-29a in myeloid (1.25 µM) and pre-B lymphoid (5 µM) progenitors were noted following exposure to 1,4-BQ. Meanwhile, increased expression of miR-181a was observed in pre-B lymphoid progenitor upon exposure to 1,4-BQ, but only at 5 µM. As for TF studies, expression of HoxB4 protein was significantly increased (p < 0.05) at all 1,4-BQ concentrations as compared to Bmi-1 and GATA3, which were significantly (p < 0.05) elevated starting at 2.5 µM of 1,4-BQ.

Conclusion

1,4-BQ induces aberration of miRNAs and transcription factors protein expression that are involved in regulating self-renewing and differentiation pathways of HSPCs. Moreover, epigenetic toxicity as evidenced from the miRNAs expression was found to be mediated by a lineage-driven mechanism. The role of cell lineage in governing the toxicity of 1,4-BQ in HSPCs lineages deserves further investigation.

Haemato-biochemical, mutagenic, and histopathological changes in Oreochromis niloticus exposed to BTX

The study of the DNA damage response in erythrocytes after exposure to volatile organic compounds (VOCs) can present evidence for its potential effect as genotoxic- biomarkers for environmental pollution. Although VOCs are dangerous pollutants, still little is known about hemotoxic, cytotoxic, and genotoxic effects of such pollutants on fish. We optimized an assay method for apoptosis and DNA damage in erythrocytes of adult tilapia fish after 15 days exposure to benzene (0.762 ng/L), toluene (26.614 ng/L), and xylene (89.403 ng/L). The highest level of apoptosis and DNA damage were recorded in benzene-exposed fish, as was the highest level of histopathological alterations in gills, liver, and kidney. The imbalance of the antioxidants profile explained the stress-case reported in exposed fish. These results suggest that hemotoxic, cytotoxic, genotoxic, and tissue damage were recorded after exposure to BTX in Oreochromis niloticus.

Fossil-fuel and combustion-related air pollution and hypertension in the Sister Study

Hypertension is a leading risk factor for disease burden, with more than 200 million disability-adjusted life-years attributed to high blood pressure in 2015. While outdoor air pollution is associated with cardiovascular disease, the joint effect of exposure to air pollution from combustion products on hypertension has rarely been studied. We conducted a cross-sectional analysis to explore the association between combustion-related air pollution and hypertension. Census-tract levels of ambient concentrations of nine fossil-fuel and combustion-related air toxics (biphenyl, naphthalene, polycyclic organic matter, diesel emissions, 1,3-butadiene, acetaldehyde, benzene, acrolein, and formaldehyde) from the 2005 National Air Toxics Assessment database and NO2 from 2005 monitoring data were linked to baseline residential addresses of 47,467 women in the Sister Study cohort. Hypertension at enrollment (2003-2009) was defined as high systolic (≥140 mm Hg) or diastolic (≥90 mm Hg) blood pressure or taking antihypertensive medication. We used log-binomial regression and quantile-based g-computation to estimate the individual and joint effects of fossil-fuel and combustion-related air pollution on hypertension. Comparing the highest to lowest quartiles, diesel emissions (prevalence ratio (PR) = 1.05, 95% confidence interval (CI) = 1.01,1.08), 1,3-butadiene (PR = 1.04, 95%CI = 1.00,1.07), acetaldehyde (PR = 1.08, 95%CI = 1.04,1.12), benzene (PR = 1.05, 95%CI = 1.02,1.08), formaldehyde (PR = 1.08, 95%CI = 1.04,1.11), and NO2 (PR = 1.08, 95%CI = 1.05,1.12) were individually associated with higher prevalence of hypertension. The PR for the joint effect of increasing all ambient air toxics and NO2 by one quartile was 1.02 (95%CI = 1.01,1.04). Associations varied by race/ethnicity, with stronger associations observed among women reporting races/ethnicities (Hispanic/Latina, non-Hispanic Black and other) other than non-Hispanic White. In conclusion, we found that air pollution from fossil fuel and combustion may be a risk factor for hypertension.

Factors affecting prevalence of neurological symptoms among workers at gasoline stations in Rayong Province, Thailand

This cross-sectional study was aimed at assessing the exposure to organic solvents and the factors affecting prevalence of neurological symptoms among workers at gas stations in Rayong Province. The sample included 200 workers at gas stations, including refueling staff, cashiers, food shop, coffee shop, and convenience store employees. Interview questionnaire included general information, work history, and neurological symptoms. Urine collection devices were used to detect organic solvents metabolized in urine, including t,t-muconic acid (t,t-MA), hippulic acid (HA), mandelic acid (MA), and methylhppuric acid (MHA).The results showed that the workers’ medians (interquartile range: IQR) of the metabolized organic solvents were as follows: t,t-MA was 393.62 (244.59) µg/g Cr, HA was 0.32 (0.14) g/g Cr, MA was 0.06 (0.02) g/g Cr, and MHA was 0.40 (0.13) g/g Cr. For prevalence of neurological symptoms, top three symptoms were headache (49.0%), dizziness (42.5%), and stress/irritability (38.5%). Working at a gas station present was neurological symptoms more than in the past was 32.5%. According to the assessment of exposure to metabolized organic solvents and factors affecting the prevalence of neurological symptoms, overtime work ≥ 6 hours and HA content greater than quartiles Q3 had an effect on neurologic symptoms (OR=2.17; 95%CI=1.23-5.10 and OR=2.15; 95%CI=1.18- 4.76, respectively). In summary, time spent working in gas stations and exposure to toluene organic solvents can cause neurological symptoms. It is recommended to reduce overtime or add breaks during work shifts or shift changes. In addition, workers should be away from the solvent.

Association of Deepwater Horizon Oil Spill Response and Cleanup Work With Risk of Developing Hypertension

IMPORTANCE

Exposure to hydrocarbons, fine particulate matter (PM2.5), and other chemicals from the April 20, 2010, Deepwater Horizon disaster may be associated with increased blood pressure and newly detected hypertension among oil spill response and cleanup workers.

OBJECTIVE

To determine whether participation in cleanup activities following the disaster was associated with increased risk of developing hypertension.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted via telephone interviews and in-person home exams. Participants were 6846 adults who had worked on the oil spill cleanup (workers) and 1505 others who had completed required safety training but did not do cleanup work (nonworkers). Eligible participants did not have diagnosed hypertension at the time of the oil spill. Statistical analyses were performed from June 2018 to December 2021.

EXPOSURES

Engagement in cleanup activities following the Deepwater Horizon oil spill disaster, job classes, quintiles of cumulative total hydrocarbons exposure level, potential exposure to burning or flaring oil, and estimated PM2.5 were examined.

MAIN OUTCOMES AND MEASURES

Systolic and diastolic blood pressure measurements were collected during home exams from 2011 to 2013 using automated oscillometric monitors. Newly detected hypertension was defined as antihypertensive medication use or elevated blood pressure since the spill. Log binomial regression was used to calculate prevalence ratios (PR) and 95% CIs for associations between cleanup exposures and hypertension. Multivariable linear regression was used to estimate exposure effects on continuous blood pressure levels.

RESULTS

Of 8351 participants included in this study, 6484 (77.6%) were male, 517 (6.2%) were Hispanic, 2859 (34.2%) were non-Hispanic Black, and 4418 (52.9%) were non-Hispanic White; the mean (SD) age was 41.9 (12.5) years at enrollment. Among workers, the prevalence of newly detected hypertension was elevated in all quintiles (Q) of cumulative total hydrocarbons above the first quintile (PR for Q3, 1.29 [95% CI, 1.13-1.46], PR for Q4, 1.25 [95% CI, 1.10-1.43], and PR for Q5, 1.31 [95% CI, 1.15-1.50]). Both exposure to burning and/or flaring oil and gas (PR, 1.16 [95% CI, 1.02-1.33]) and PM2.5 from burning (PR, 1.26 [95% CI, 0.89-1.71]) for the highest exposure category were associated with increased risk of newly detected hypertension, as were several types of oil spill work including cleanup on water (PR, 1.34 [95% CI, 1.08-1.66]) and response work (PR, 1.51 [95% CI, 1.20-1.90]).

CONCLUSIONS AND RELEVANCE

Oil spill exposures were associated with newly detected hypertension after the Deepwater Horizon disaster. These findings suggest that blood pressure screening should be considered for workers with occupational hydrocarbon exposures.

Dose-response relationships between polycyclic aromatic hydrocarbon exposure and blood cell counts among coke oven workers: a sex-stratified analysis

OBJECTIVES

To explore sex differences and dose-response relationships between nine urinary polycyclic aromatic hydrocarbon (PAH) metabolites and neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and complete blood counts among coke oven workers.

DESIGN AND SETTING

A cross-sectional study with stratified sex was conducted in Shanxi, China.

PARTICIPANTS

A total of 458 male workers and 226 female workers were selected.

PRIMARY AND SECONDARY OUTCOME MEASURES

General linear models, p values for trend tests and natural cubic spline models were used to explore the dose-response relationships between nine urinary PAH metabolites and NLR, PLR and complete blood counts.

RESULT

Compared with male workers, female workers had lower exposure level of PAH (0.95 ng/mL vs 1.38 ng/mL). Only among female workers did we observe that a 1-unit increase in lg(1-OHPyr) was related to a 0.149 (95% CI: 0.055 to 0.242; p for trend=0.041) and 0.103 (95% CI: 0.025 to 0.181; p for trend=0.007) increase in lg(NLR) and lg(PLR), and a 0.116 (95% CI: -0.179 to -0.054; p for trend=0.007) decrease in lg(lymphocyte counts (LYMs)). A 1-unit increase in lg(2-OHNap) was related to a 0.045 (95% CI: 0.003 to 0.086; p for trend=0.037) increase in lg(PLR) and a 0.029 (95% CI: -0.056 to -0.002; p for trend=0.030) and 0.016 (95% CI: -0.029 to -0.003; p for trend=0.010) decrease in lg(white blood cell counts (WBCs)) and lg(haemoglobin (HGB)).

CONCLUSION

Female workers' NLR, PLR, WBCs, HGB and LYMs may be more susceptible than those of male workers when affected by PAH.

Correlation between Workers’ Characteristics and Health Complaints Due to Exposure to Organic Solvents in the Sidoarjo Offset Printing

Introduction: Organic solvents are chemicals that are often used by the printing industry and contain Benzene, Toluene, and Xylene which are toxic to humans. Chemicals that contain organic solvents are ink, glue, and others. Workers who are regularly exposed to organic solvents can have health complaints. The purpose of this study was to determine the correlation between workers’ characteristics and health complaints due to exposure to organic solvents in the Sidoarjo offset printing. Methods: This research was an observational study with cross sectional design. Population in this research was 30 workers. The sampling technique used simple random sampling and from the calculation results were obtained 24 respondents. This study had an independent variable, which was workers’ characteristics consisting of age, smoking habits, and work tenure. The dependent variable was health complaints of printing workers. Data collection used questionnaires and interviews. The research data were analyzed using fisher’s exact test to show the correlation between workers’ characteristics and health complaints. Results: The result of the analysis test found that there was no correlation between age (p=0.386) and smoking habits (p=0.376) with health complaints of workers. Moreover, the analysis test showed that work tenure variable had a correlation with health complaints of workers (p=0.041). Conclusion: A factor related to health complaints of workers was work tenure.Keywords: health complaints, organic solvents, worker characteristics

Correlation between Workers’ Characteristics and Health Complaints Due to Exposure to Organic Solvents in the Sidoarjo Offset Printing

Introduction: Organic solvents are chemicals that are often used by the printing industry and contain Benzene, Toluene, and Xylene which are toxic to humans. Chemicals that contain organic solvents are ink, glue, and others. Workers who are regularly exposed to organic solvents can have health complaints. The purpose of this study was to determine the correlation between workers’ characteristics and health complaints due to exposure to organic solvents in the Sidoarjo offset printing. Methods: This research was an observational study with cross sectional design. Population in this research was 30 workers. The sampling technique used simple random sampling and from the calculation results were obtained 24 respondents. This study had an independent variable, which was workers’ characteristics consisting of age, smoking habits, and work tenure. The dependent variable was health complaints of printing workers. Data collection used questionnaires and interviews. The research data were analyzed using fisher’s exact test to show the correlation between workers’ characteristics and health complaints. Results: The result of the analysis test found that there was no correlation between age (p=0.386) and smoking habits (p=0.376) with health complaints of workers. Moreover, the analysis test showed that work tenure variable had a correlation with health complaints of workers (p=0.041). Conclusion: A factor related to health complaints of workers was work tenure.Keywords: health complaints, organic solvents, worker characteristics

Effects of the occupational exposure on health status among petroleum station workers, Khartoum State, Sudan

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Mean blood lead level for exposed group of non-smokers was 0.58 mg/l.

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Mean blood lead level for exposed group of smokers was 1.49 mg/l.

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Mean value of lead in urine of smokers were 1.59 mg/L & 1.16 mg/L in both groups.

Objective

The hazards of petroleum station activities are greatly emphasized due to their negative impact on workers’ health and safety concerns. This study aims to assess the effect of occupational exposure among the workers in various petroleum station at the Khartoum State, Sudan.

Methods

An analytical and experimental study design is followed where 60 participants were selected through purposive sampling technique. The participants were recruited from the petroleum workstation and were considered as the lead exposed group whereas the participants who lived faraway from the petroleum station and had no exposure to lead were considered as un-exposed group. To avoid the effects of smoking on lead concentration we further divided these groups into smokers and non-smokers. IBM, SPSS was used for the statistical analysis of the collected data.

Results

The results show that there is no significant difference in white blood cells (WBCs) count between exposed and unexposed lead group. We also did not find significant difference in Red blood cells (RBCs) count. Participant from both groups had normal range of haemoglobin (Hb). However, haematocrit (Hct) levels were elevated in both of these groups. We also tested the platelet count in these groups and found that platelet count was slightly lower in lead exposed group as compared to the unexposed group but average count was found within the normal range. Finally, the lead concentration in serum and urine was detected of the participants. Results reveal that the serum lead concentration of non-smokers (0.58 mg/l) in the exposed group was higher than in non-smokers of unexposed group (0.49 mg/l). The lead concentration in serum of smokers in exposed group was also high (1.49 mg/l) than the lead concentration detected in serum of smokers in unexposed group (1.14 mg/l). Urine lead levels of exposed group was also high than the unexposed group in smokers and non-smokers. Mean value of lead in urine among non-smokers of the exposed and unexposed group were 0.76 mg/L and 0.19 mg/L respectively. In the case of smokers, 1.59 mg/L and 1.16 mg/L were the mean value of lead in urine for both exposed and unexposed groups respectively.

Conclusion

From the given results it can be concluded that health safety measures for workers must be implemented to maintain good health status of workers at petroleum stations.

Acarbose protects from central and peripheral metabolic imbalance induced by benzene exposure

Benzene is a well-known human carcinogen that is one of the major components of air pollution. Sources of benzene in ambient air include cigarette smoke, e-cigarettes vaping, and evaporation of benzene containing petrol processes. While the carcinogenic effects of benzene exposure have been well studied, less is known about the metabolic effects of benzene exposure. We show that chronic exposure to benzene at low levels induces a severe metabolic imbalance in a sex-specific manner, and is associated with hypothalamic inflammation and endoplasmic reticulum (ER) stress. Benzene exposure rapidly activates hypothalamic ER stress and neuroinflammatory responses in male mice, while pharmacological inhibition of ER stress response by inhibiting IRE1α-XBP1 pathway significantly alleviates benzene-induced glial inflammatory responses. Additionally, feeding mice with Acarbose, a clinically available anti-diabetes drug, protected against benzene induced central and peripheral metabolic imbalance. Acarbose imitates the slowing of dietary carbohydrate digestion, suggesting that choosing a diet with a low glycemic index might be a potential strategy for reducing the negative metabolic effect of chronic exposure to benzene for smokers or people living/working in urban environments with high concentrations of exposure to automobile exhausts.

Impact of Petroleum Exposure on Some Hematological Indices, Interleukin-6, and Inflammatory Markers of Workers at Petroleum Stations in Basra City

Background

Occupational and environmental exposure to several pollutant factors such as petroleum products containing benzene has toxic effects on different body systems. The hematopoietic system and immune system are among the affected systems. This study aims to investigate the effect of benzene exposure on some blood parameters of workers at several fuel stations in Basra city, as well as to reveal if the continuous exposure may induce an inflammatory response, which is reflected by changes in some hematological and inflammatory markers.

Methods

The study included two groups of males. The first group consists of 72 exposed workers at petrol stations in different locations in the Basra city. The other group is the control group, which consists of 75 nonexposed subjects (students and faculty members of the college). Different hematological parameters (WBC, RBC, HGB, MCV, MCHC, and MCH) have been evaluated. Serum concentrations of IL-6 and hs-CRP were estimated in all workers and nonexposed using enzyme-linked immunosorbent assay (ELISA).

Results

Data showed significant hematological changes in the exposed workers, and that anemia was a common disorder among them. Furthermore, there was a significant decline in WBC and different types of WBC including lymphocytes, monocytes, and neutrophils in the exposed workers. Erythrocyte sedimentation rate and serum levels of interleukin-6 and hs-CRP were significantly higher in exposed workers than in nonexposed. A significant correlation was identified among blood parameters, while a strong inverse correlation was identified between both MCHC and ESR. The most significant inverse correlation was found between RBC and IL-6 and MCH with hs-CRP. In addition, a significant negative correlation was found between monocytes and IL-6.

Conclusion

The changes in all hematology and inflammatory parameters refer to damage in the hematopoietic system due to continuous exposure to vapors of petrol products, which also result in a significant increase in interleukin-6.

Polymer-assisted synthesis and applications of hydroxyapatite (HAp) anchored nitrogen-doped 3D graphene foam-based nanostructured ceramic framework

Hydroxyapatite anchored nitrogen-doped three-dimensional graphene (HAp-N3DG) skeletal network (foam) based nanostructured ceramic framework (CF) was developed through a polymer-assisted solvothermal route.