جستجوی مقالات مرتبط با کلیدواژه « benzene » در نشریات گروه « پزشکی »

The measurement and analysis of pollutants is undoubtedly the first step in controlling them because, without complete knowledge of the quality and quantity of pollutants, it will not be possible to compare them with the permitted limits and ultimately control them. This descriptive-analytical study focused on the oil refineries and chemical industries. Approximately 279 air samples from 18 complexes in an industrial area were collected for this study in the winter of 2020 and 334 samples in the summer of 2021. In this study, 14 volatile organic compounds (VOCs) were examined, measured, and sampled using procedures recommended by the National Institute for Occupational Safety & Health (NIOSH). Finally, GC/FID and GC/MS devices were used to analyze the samples. SPSS version 22.0 was used to analyze the results. In this study, it was determined that the mean of the majority of the compounds in all of the complexes was higher in the summer than in the winter (p<0.05). Additionally, according to the findings, in both the winter and summer seasons, the average ratio of benzene to BTX, BTEX, and all VOCs showed the highest percentage (67.2%) and the average ratio of xylene concentration to these three variables showed the lowest percentage (3.15-7.35%). The findings of this study indicate that the multiplicity of pollution sources and the accumulation of numerous complexes in this area have increased the amount of pollution spread throughout the region's air. As a result, it is advised to use engineering solutions to reduce the amount of pollution.

The petrochemical industry as a modern industry, despite the positive outcomes it has brought to mankind, is a source of gaseous and aerosol pollution and industrial effluents on a large scale, which can have direct and indirect destructive effects on the environment and human life. This study investigated the relationship between the amount of airborne benzene with the amount of trans,trans-muconic acid (ttMA) and hippuric acid metabolites in the urine of workers working in petrochemical complexes with different exposure times and methods.

For this purpose, breathing the air of different petrochemical plants of Bou Ali Sina was sampled by the National Institute for Occupational Safety and Health 1501 method, and the urine of workers (n = 24) was also sampled in these units. In addition, the amount of benzene in the air samples and the amount of urinary metabolites of ttMA and hippuric acid were analyzed in urine samples sent to the laboratory using a high-performance gas chromatography-mass spectrometry device and gas-liquid chromatography. Finally, urinary creatinine was measured by an ultraviolet-visible spectrophotometer.

The results showed that the concentration of benzene in the aromatic unit had the highest value, which had a higher level of pollution than both standards. The xylene mixing unit with a concentration of 3.6 μg/m3, the loading unit with a benzene content of 3.4 μg/m3, and a tank unit with 2.8 μg/m3 had a lower amount of benzene pollution compared to the Occupational Safety and Health Administration permissible exposure limit-short-term exposure limit (OSHA PEL-STEL) standard but had higher pollution levels in comparison to the OSHA PEL-TWA (time-weighted average) standard. In the sampling unit of the laboratory with a benzene amount of 0.94 μg/m3 and in the technician unit of the laboratory, the amount of pollution was lower than both OSHA PEL-TWA and OSHA PEL-STEL standards. The aromatic unit demonstrated the highest amount of benzene, while the lowest amount was related to the laboratory section.

The results of the measurement of urinary benzene metabolites revealed that the concentration of urinary phenol and inhaled benzene in evening shift workers was higher than the corresponding amount in the morning shift workers, which may be due to the high level of pollution evenings compared to the morning. On the other hand, the results represented that the average hippuric acid in the exposed people (n = 24) was higher than the control (n = 20) so that it was 0.35 in the exposed and 0.26 in the control subjects. In addition, the average muconic acid in the exposed and control subjects decreased to 1.57 and 0.89, respectively. The minimum and maximum amounts of muconic and hippuric acids in the exposed subjects were 0.97 and 2.62, as well as 0.14 and 0.83, respectively. The maximum and minimum concentrations of muconic and hippuric acids were 2.62 and 0.97, as well as 0.83 and 0.14 in exposed subjects, respectively, which was less than muconic acid.

 This article evaluates the health risk of occupational exposure to BTEX compounds, cancer risk, and noncancer risk analysis among gas station workers. 

 This cross-sectional research evaluates pollutants rank of risk released at Ahvaz stations in Iran. We have collected 96 samples of workers exposed to BTEX and eight samples for control in the ambient air. The National Institute for Occupational Safety and Health (NIOSH) recommended BTEX method numbers 1500 and 1501 for sampling and analysis. To evaluate the risk assessment of pollutants, we utilized a semi-quantitative method offered by Singapore's Occupational Safety and Health Division. 

 The average benzene concentration in the operators' breathing zone (1.202 0.83 ppm) was greater than the threshold limit values-time weighted average (TLVs-TWA) (P < 0.05). Other contaminants had concentrations that were lower than the ACGIH's TLV-TWA (P < 0.05). In gas stations, benzene has a very high danger ranking among chemical compounds. Toluene, ethyl benzene, and xylene in the employees' breathing zone posed a modest risk. The average cancer risk for benzene-exposed operators, head shift workers, and supervisors was calculated to be 4.46 × 10−3, 2.90 × 10−3, and 2.08 × 10−3, respectively. The risk of cancer is projected to be higher than the tolerable level of 10-6. 

 In unique, long-term exposure to benzene has been linked to an increased risk of cancer and toxic effects, and a health-risk assessment can provide useful information about current workplace contaminants.

Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) as the ozone precursors have been classified as the hazardous air pollutants because of their negative effects on humans. This article presents the results of the first assessment of source identification, spatial distribution and BTEX's OzoneForming Potential (OFP) in Zarand.

The current study was conducted at 30 geographically separated locations, in Zarand, Kerman, southeastern Iran, during the summer and winter of 2020. BTEX samples were collected using passive samplers and then analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). Spatial variations were surveyed using the Kriging method in GIS.

Total BTEX levels (79.26±26.87 µg/m3) during the summer were greater than their levels in the winter (37.38±29.18 µg/m3). The ranking of BTEX level in all samples followed as: toluene>m,pxylene>oxylene>ethylbenzene>benzene. The overall OFP of 374.79±135.08 µg/m3
in the summer and 172.61±148.81 µg/m3 in the winter were more than 100 µg/m3 as recommended guideline defined by World Health Organization (WHO), with toluene having the highest potential.

According to the results of the present study, BTEX relative abundances in all samples were toluene>m,p-xylene>oxylene>ethylbenzene>benzene. Despite of concerns among inhabitants and
workers, benzene concentration was lower than other studied species. Control measures such as management of fuel use in motor vehicles and industries and development of green space must be adopted to attenuate the level of toluene in the atmosphere in the studied area.

In Saudi Arabia, fuel dispensing facilities commonly present around the residential places, educational institutions, and various health care facilities. Fuel pollutants such as benzene, toluene, and xylenes (BTX) and its alkyl derivatives are harmful to human health because of their toxic, mutagenic, or carcinogenic properties. The aim of this study was to determine the BTX concentration levels of common pollutants in and around fuel stations and their harmful health effects in the urban cites of KSA.

Forty fuel dispensing facilities were randomly selected on the basis of three different areas: residential, traffic intersection, and petrol pump locations (refueling stations). Portable ambient analyzer was used for measuring BTX concentration. t‑test was applied to determine the difference between these different areas.

All mean concentration values of pollutants such as BTX around residential, traffic intersection, and fuel stations are exceeding the limits of air quality standards values (P < 0.01). The mean levels of benzene are 10.3 and 11.07 ppm in Dammam and Khobar, respectively, and they exceed the reference level of 0.5 ppm. Hazard quotient was more than >1, which shows that carcinogenic probability has increased those who were living and working near fuel stations.

The results found that the high concentration of pollutants (BTX) is in the environment around fuel stations. The environmental contamination associated with BTX in petrol fuel stations impulses the necessity of preventive programs to reduce the further air quality deterioration and reduce the harmful health effects.

Hydrocarbons (benzene, toluene, ethyl benzene and xylene (BTEX) found in gasoline and organic solvents are ubiquitous in the environment, and are known to have toxic effects in human system. This study therefore investigated the thyroid function of workers occupationally exposed to gasoline and paint products using TSH, T3 and T4 as markers. A total of 162 subjects were recruited for this study; (56 gasoline pump attendants and 56 paint factory workers) and 50 subjects as control. Blood sample was collected from each subject and thyroid function tests (T3, T4 and TSH), were assayed using Enzyme linked immunosorbent assay (ELISA) techniques. The mean values of TSH was significantly lower in the gasoline workers and painters compared to the control subjects (1.73±0.89, 1.66±0.84 Vs 2.09±1.06µIU/ml; F= 3.169, p<0.05). The mean values of T4 was significantly lower in gasoline workers and painters when compared to the control subjects (9.09±1.87, 9.63±1.90 Vs 12.06 ± 1.82µg/dl; F= 37.430, p<0.05). However, the mean levels of T3 was significantly higher in gasoline workers and painters compared to the control subjects (2.56± 0.65, 2.72 ± 0.65 Vs 1.03 ± 0.30ng/ml; F= 161.292, p<0.05). The mean body mass index, systolic and diastolic blood pressures were similar in all the groups. The levels of TSH showed a significant inverse correlation with the duration of exposure in the subjects exposed to gasoline (r=-0.326, p<0.05), whereas the levels of T3 showed a positive significant correlation with the duration of exposure in paint workers (r=0.301; p<0.05). This study demonstrated that both gasoline and paint showed similar effects on the thyroid parameters of the subjects under study, which is suggestive of T3 thyrotoxicosis.

Due to the fact that in the process of car painting in the automotive industry, sludge containing dangerous compounds of benzene, toluene, ethylbenzene, xylene which cannot be released into the environment without purification, is inevitably produced, this study was conducted to investigate the feasibility of removing BTEX (benzene, toluene, ethylbenzene, and xylene) from the paint sludge of Saipa Automotive Company using Eisenia fetida worms.

This is an experimental study. First, mixtures with different proportions of sludge were prepared and loaded in suitable boxes. After preparing the desired sludge, their quantitative and qualitative characteristics were determined in terms of type and amount of BTEX, volatile materials, moisture content, and C/N ratio. Then, to check the changes in BTEX, sampling was performed on different days during 90 days. BTEX measurements were performed using GC-MS method (NIOSH Method 1501).

The results showed that in the best mixing ratio of sludge, the amount of benzene decreased from 3 mg to less than 0.01 mg in 30 days, toluene decreased from 1.5 mg to zero over a 45-day period, ethyl benzene was reduced from 7 mg to zero mg over 70 days, and xylene decreased from 18 mg to 0.9 mg over 90 days. In addition, in the same optimal mixing ratio, the amount of volatile organic matter, pH, and C/N ratio also had a decreasing trend in the vermicomposting process.

According to the results, E. fetida worms are able to work in mixed sludge and have the ability to break down BTEX.

 The aim of this study is to determine the benzene, toluene, ethylbenzene, and xylene (BTEX) concentration levels in and around the fuel station and its harmful health effects in the city of Dammam and Al Khobar, Saudi Arabia. 

 Forty fuel-dispensing facilities were randomly selected on the basis of three different areas: residential, traffic intersection, and petrol pump locations (refueling stations). Samples were collected using coconut shell charcoal cartridges, and the portable ambient analyzer was used for measuring BTEX concentration. 

 Results shows that the average concentration of BTEX levels around fuel stations was 10.30, 4.09, and 2.47 ppm, respectively. All mean concentration values of BTEX around residential, traffic intersection, and fuel stations are exceeding the limits of air quality standards values (P < 0.01). The mean concentration of BTEX around the residential area, side street, and direct street was as follows: benzene 8, 12.2, and 11.5 ppm; toluene 2.5, 5.95, and 3.37 ppm; and xylene 2, 2.13, and 2.7 ppm. Hazard quotient was >1, which showed that carcinogenic probability has increased those exposed to this toxic chemical. 

 Values for BTEX were greater than those found in the neighboring residential area of the city and even 100 m away from the fuel station which can have a negative impact on the health of several residences. The environmental contamination associated with BTEX in petrol fuel stations impulses the necessity of preventive programs to reduce further air quality deterioration and reduce the harmful health effects.

 Chronic exposure to benzene or its derivative (benzoquinone and hydroquinone) in humans may result in bone marrow damage followed by development of leukemia. Induction of extra cellular signaling pathways in microenvironment of bone marrow of patients with acute myeloid leukemia (AML) may lead to progression of disease and treatment resistance. Mesenchymal stromal cells (MSCs) are a subpopulation of multipotent cells of non-haematopoietic origin. They are increasingly recognized as a central component of the bone marrow (BM) microenvironment that contributes to the structure and function of the BM niche. MSCs play significant roles in regulation of homing, self-renewal, differentiation, and proliferation of hematopoietic stem cells (HSC) through production of various crucial elements in hematopoietic niche. Niches are local tissue microenvironments that maintain and regulate stem cells. Previous studies have shown that benzene is one of the important risk factors for AML.

 This study aimed to evaluate the effect of low doses of benzoquinone on the expression levels of some hematopoietic function related genes including CXCL12 and Kit ligand (KITLG) in MSCs.

 MSCs obtained from bone marrow mononuclear cells of healthy volunteer and cultured in the proper medium. After characterization with standard methods, MSCs were exposed to two doses of 5 and 10 micro molar (µM) of benzoquinone; then, the expression of KITLG and CXCL12 genes were evaluated by real time PCR method.

 The results indicated that the expression of KITLG and CXCL12 genes were increased after treatment with benzoquinone, specifically with 5 µM dose.

 The results of our study along with well-established role of KITLG/SCF signaling pathways and the CXCL12-CXCL4 axis in maintenance of the niche and cancer development, benzene metabolite, benzoquinone, is among the major factors in causing acute myelogenous leukemia.
 

Exposure to benzene has been associated with a range of acute and long-term adverse health effects. We aimed to estimate national and provincial level of benzene emissions from 1990 to 2013 in Iran.

Benzene emission was estimated through two main sources: unburned benzene content of fuel and evaporated benzene. Unburned benzene content of fuel estimated by gasoline consumption rate, kilometers traveled by non-diesel-based cars, and benzene emission factor. Evaporated benzene estimated by evaporated gasoline and volumetric percentile of benzene.

The estimated provincial annual mean benzene estimation range was between 5.9 (ton) and 1590 (ton) from 1990 to 2013. Our results showed that maximum benzene emission over the past 24 years occurred in Tehran, (Mean± SD) (1147.2±308.5) (ton)), Isfahan (423.4±132) (ton)), Khorasan Razavi (410.4±122.2) (ton)) provinces, respectively. There was an upward trend in the benzene emission into atmosphere at national and subnational level from 1990 to 2007. Also a significant decrease trend is observed from 2008 to 2013.

The findings of this study will provide an insight into the extent of emitted benzene in the atmosphere at different regions of Iran for policy makers and scientists and may be a groundwork for field studies on benzene concentration estimation.

Rapid rise in petrol pump filling station is seen in the last decade, and air pollution had increased drastically. Air pollutants and components in petrol may have delirious effect on respiratory health. Petrol pump workers are exposed to both factors, whereas auto-rickshaw drivers are exposed mainly to air pollutants. In the present study, respiratory function in petrol pump workers was compared with auto-rickshaw driver and healthy controls.

This was the cross-sectional study done on petrol pump workers, auto-rickshaw drivers, and healthy volunteers. ndd Large TrueFlow™ (EasyOne) spirometer was used to assess pulmonary function. One-way ANOVA and Chi-square test were used using statistical software.

No significant difference was seen in various spirometry parameters studied. Furthermore, no significant difference was observed the pattern of the lung function in three groups.

Nine years of occupation as petrol pump worker and auto-rickshaw drivers are not having any significant effect on lung function; however, large multicentric trials are recommended, whereby the role of various factors controlling pollution would be studied.