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Biomonitoring-based exposure assessment of benzene, toluene, ethylbenzene and xylene among workers at petroleum distribution facilities
Abstract
Elevated emissions of volatile organic compounds, including benzene, toluene, ethylbenzene, and o, p, and m-xylenes (BTEX), are an occupational health concern at oil transfer stations. This exploratory study investigated personal exposure to BTEX through environmental air and urine samples collected from 50 male workers at a major oil distribution company in Iran. Airborne BTEX exposures were evaluated over 8h periods during work-shift by using personal passive samplers. Urinary BTEX levels were determined using solid-phase microextraction with gas chromatography mass spectrometry for separation and detection. Mean exposure to ambient concentrations of benzene differed by workers' job type: tanker loading workers (5390μg/m(3)), tank-gauging workers (830μg/m(3)), drivers (81.9μg/m(3)), firefighters (71.2μg/m(3)) and office workers (19.8μg/m(3)). Exposure across job type was similarly stratified across all personal exposures to BTEX measured in air samples with maximum concentrations found for tanker loading workers. Average exposures concentrations of BTEX measured in urine were 11.83 ppb benzene, 1.87 ppb toluene, 0.43 ppb ethylebenzene, and 3.76 ppb xylene. Personal air exposure to benzene was found to be positively associated with benzene concentrations measured in urine; however, a relationship was not observed to the other BTEX compounds. Urinary exposure profiles are a potentially useful, noninvasive, and rapid method for assessing exposure to benzene in a developing and relatively remote production region.
... However, only the mean concentration of benzene contaminations was higher than the recommended standard value. These results are consistent with the findings of Heibati et al. (2018) and Rafiee et al. (2019). Heibati et al. concluded that the mean concentration of benzene contaminations was higher than the recommended standard (Heibati et al. 2018). ...
... These results are consistent with the findings of Heibati et al. (2018) and Rafiee et al. (2019). Heibati et al. concluded that the mean concentration of benzene contaminations was higher than the recommended standard (Heibati et al. 2018). In addition, Rafiee et al. found that benzene contaminant had a higher mean concentration than the recommended standard (Rafiee et al. 2019). ...
... Figures 2, 3, and 4 show the linear regression diagrams of benzene, toluene, and xylene with their biomarkers. Numerous studies have reported results consistent with the present study, so that the results of a study by Heibati et al. and Shah Mohammadi et al. stated that there was a direct and linear relationship between the average concentration of benzene and its metabolic value (Davoud Shahmohammadi 2018;Heibati et al. 2018). In a study by Moradi et al., linear regression of benzene and toluene contaminations predicted 77% of the changes in the biological value of these contaminations (Moradi et al. 2019). ...
Nowadays, workers in petrochemical industry might be exposed to organic volatile compounds, including benzene, toluene, ethylbenzene, and xylene (BTEX). The aim of this study was to investigate the concentration of BTEX contaminations and the biological index in employees of petrochemical sites in the west of Iran. The study was conducted as a cross-sectional study on 30 stations and 60 inhalation and biological samples collected in winter and summer. The NIOSH 2549 and 1501 methods were used for sampling and analyzing the inhaled samples. Gas chromatography-mass spectrometry (GC-MS) equipped with flame ionization detector and high-performance liquid chromatography (HPLC) was used to measure the volatile contaminations. The results showed that the mean concentrations of benzene, toluene, and xylene were significantly different in summer and winter. Significant and strong correlations were observed between the concentrations of benzene, toluene, and xylene and the biological values (r > 0.7). Moreover, the concentration of benzene (β = 0.836), toluene (β = 0.718), and xylene (β = 0.786) predicted the changes in their biological values. Given the hazardous concentrations of benzene and toluene in industrial plants and the correlation of the concentration levels and biological values, management and control strategies should be implemented to eliminate and reduce the pollutants and the effects.
... Toluene as an aromatic hydrocarbon is widely used in the industry and many people are directly or indirectly exposed to it (Heibati et al., 2018). As an industrial solvent, it is utilized in many chemical products and industries, including petrochemical, plastic, agriculture, textile and pharmaceutical. ...
... As an industrial solvent, it is utilized in many chemical products and industries, including petrochemical, plastic, agriculture, textile and pharmaceutical. Exposure to toluene often occurs through the respiratory system because of the volatility of this formulation (Heibati et al., 2018). Previous studies have demonstrated some toxic effects of toluene through long exposure or high concentrations (Prell et al., 2011;Abouee-Mehrizi et al., 2021). ...
Noise and toluene are among the numerous physical and chemical pollutants that can induce adverse effects on different body tissues and systems; nevertheless, most studies have only experimented the auditory changes induced by co-exposure to them. The present in-vivo study aimed to examine the endocrine effects of co-exposure to toluene and noise on the testes and adrenal glands. In this experimental study, 24 healthy male New Zealand White rabbits were used. The noise intensity was 100 dB (white noise) and the toluene concentration was 1000 ppm for two consecutive weeks. The luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, cortisol and adrenocorticotropic hormone (ACTH) were measured using the enzyme-linked immunosorbent assay (ELISA) method. The hematoxylin and eosin stain method (H&E) was
performed for the histopathological analysis. Comparing different parameters in different groups on post-exposure days was carried out using GEE (generalized estimating equations) method. The results indicated that noise and toluene increased cortisol, LH and FSH levels during different days after the exposure. Exposure to toluene and noise made vacuolization and reduction of primary spermatogonial cells in the testes. Moreover, lymphocyte infiltration, congestion, swelling and vacuolization were detected in adrenal glands through exposure to toluene and noise. Toluene and noise induced
different destructive effects on the endocrine system. More studies are required to elucidate other endocrine changes induced by exposure to toluene and noise.
... Our findings are comparable with those reported previously in other occupational settings (Brajenović et al., 2015;De Palma et al., 2012). For instance, Heibati et al. (2018) reported mean levels of benzene, toluene, and xylenes of 11.83, 1.87, and 3.76 μg/l, respectively; 1.2 to 11.5-times higher than our findings in workers at petrol stations. However, the mean level of ethylbenzene in the present study was 1.39 fold higher than the value reported by Heibati et al. (2018). ...
... For instance, Heibati et al. (2018) reported mean levels of benzene, toluene, and xylenes of 11.83, 1.87, and 3.76 μg/l, respectively; 1.2 to 11.5-times higher than our findings in workers at petrol stations. However, the mean level of ethylbenzene in the present study was 1.39 fold higher than the value reported by Heibati et al. (2018). ...
Children are highly susceptible to environmental contaminants as their physiology and some metabolic pathways differ from adults. The present cross-sectional study aimed to assess whether exposure to benzene, toluene, ethylbenzene, o,p-xylene, and m-xylene (BTEX) affects oxidative DNA damage in street children using a bio-monitoring approach. Thirty-five boys (7-13 years of age), exposed by working at a busy intersection, and 25 unexposed boys of similar age and living in the neighborhood near the busy intersection were recruited. Urinary un-metabolized BTEX levels were quantified by a headspace gas chromatography-mass spectrometry (GC-MS). Urinary malonaldehyde (MDA) was measured with spectrophotometry. Sociodemographic and lifestyle conditions information was collected by interviews using administered questionnaires. Exposed subjects provided urine before (BE) and after work exposure (AE), while unexposed boys gave a single morning sample. Urinary BTEX concentrations in BE samples were similar to unexposed. Concentrations in AE samples were 2.36-fold higher than observed in BE samples (p < 0.05) and higher than those in the unexposed group (p < 0.05). In addition, urinary MDA levels in AE samples were 3.2 and 3.07-times higher than in BE samples and in the unexposed group (p < 0.05). Environmental tobacco smoke (ETS) increased urinary BTEX and MDA levels in both groups. Our findings confirm that street children working at busy intersections are significantly exposed to BTEX, which is associated with oxidative stress. Implementing protective measures is crucial to reduce exposure and to improve health outcomes in this group.
... VOCs have many types, but emphasis is placed on mono-aromatic volatile organic compounds, namely benzene, toluene, ethylbenzene, and xylene (BTEX). This type of VOC is often considered a carcinogenic compound (Heibati et al., 2018;Masekameni et al., 2018). Benzene and ethyl benzene exposure is usually associated with an increased incidence of hematopoietic cancer and a risk of leukemia (Khalade et al., 2010). ...
... These results indicate that the exposure of toluene in Surabaya printing was above the threshold. The health effect of toluene exposure is very dangerous, in short term it can cause dermatitis (red, itchy, and dry skin), while in long-term, it can affect the nervous system, in which a number of studies on paint workers and workers in the rubberized-matting industry had long-term exposure to the potential for central nervous system damage (Heibati et al., 2018;Bioindustries, 2020). Based on the results of research conducted by Kuranchie, Angnunavuri and Attiogbe, (2019) high BTX exposure conditions can reduce or eliminate a person's level of consciousness. ...
Introduction: Safe concentrations of non-carcinogenic toluene can cause adverse effects on health. Based on the results of a research, toxic effects on toluene exposure can cause cancerous (leuikimia) and non-cancerous (aplastic anemia). The Research objective to determine the safe concentration of non-carcinogenic toluene in Surabaya printing. Methods: The research design used was observational analytic, cross sectional research design with a quantitative approach. The research location was a printing press in Surabaya. The variables in this study were the concentration of toluene levels (ppm) and RQ in workers. Total population was 37 workers, while the study sample was taken using accidental sampling method with a total sample of 30 respondents. The formula for determining the concentration of toluene non carcinogen intake is (CxRxtExfExDt): (Wbx30x365). Results: The concentration value of toluene exposure was greater than the standard set by labor regulations No. 5 of 2018 about occupational health and safety of the work environment by 0.2 ppm. A total of 10% of workers falls under normal category, 73% above normal category and 27% below normal category. Conclusion: In this study, we found new findings, viz the concentration of toluene exposure in Surabaya printing area was above normal with a concentration of 0.2 ppm and this is considered not normal.
Keywords: non carcinogenic toluene, safe concentration, surabaya printing, toluene
... Exposure to BTEX compounds in petrol industry workers was measured along with the concentration of chemicals in ambient air. Mean urinary volatile organic compound (VOC) concentrations ranged up to 11.83 μg/L for highly exposed loading workers and 2.58 μg/L for office workers (Heibati et al. 2018). Biomonitoring after inhalation exposure of mixed BTEX compounds is modelled and is available (Marchand et al. 2015). ...
... As benzene and alkylbenzenes are prevalent (eco)toxic compounds, many authors reviewed the toxicology of them (IARC Monograph vol. 120 (2017); Bolden et al. 2015;Heibati et al. 2018). Many drug users (even heavy drug users-poly drug use) chose solvents or glues to inhale their volatile compounds for the dazzling sensation and euphoric properties. ...
Medicinal thermal waters consist of a mixture of different organic and inorganic compounds. Traditionally, these waters are only characterized and classified by their inorganic composition; however, the bioavailability of the majority of these inorganic compounds is limited. Many authors investigate the organic fractions of thermal waters. These authors propose that these compounds have a potential effect on health. To elucidate the underlying mechanisms, it is crucial to know the composition of the organic fractions. The absorption of these compounds on intact skin or mucosa is notable. Some of them have local anaesthetic effect or affect receptors in the central nervous system. In the knowledge of the chemical composition, we are able to estimate the possible pharmacological effect or might be able to assess possible toxicity risks. In the present article, we aim to review possible health effects of two of the identified organic fractions: benzene and alkylbenzenes and phenolic compounds that might correlate with the therapeutic effect on rheumatological or other diseases.
... This can contribute to the carcinogenic effects and other possible health impacts of BTEX compounds. It is important to minimize exposure to these compounds to reduce the risk of adverse health effect [23][24][25]. ...
Purpose: Millions of workers in various occupational settings face potential exposure to hazardous substances, including a wide array of compounds found in petroleum derivatives. Among these compounds, toluene and xylene are prominent examples known for their genotoxic properties. Toluene and xylene, both belonging to the aromatic compound family, give rise to the main metabolic byproducts of hippuric acid, (o, p, m) methyl hippuric acid.
Methods: HPLC approach is used to analyze the urine of petroleum workers who are exposed to toluene and xylene to assess their concentrations of the metabolites. Hippuric acid and (o, p, m) Methyl hippuric acid. The micronucleus assay of buccal mucosa smears can be used to evaluate the genotoxic effects of these exposures in petroleum workers. Occupational exposure to petroleum and its derivatives may cause DNA damage and chromosomal abnormalities in buccal mucosa cells, indicating a potential increased risk of cancer and other health effects.
Results: The Method was developed for Hippuric acid and (o, p, m) Methyl hippuric acid of urinary samples of petroleum workers. The urinary HA, (o, p, m) MHA levels in cases were found to be 26.042 µg/ml with standard deviation value is 12.38. The study focused to examine the cellular alterations in exfoliated oral epithelial cells, particularly cytomorphometry and micronuclei, which were examined using PAP-stained smear to determine the existence of micronuclei.
Conclusions: The urinary HA, (o, p, m) MHA levels were highly significant and the prevalence of the condition was found to be greater among petroleum workers compared to the control population. It is observed that more micro nuclei were found in buccal mucosa of petroleum workers than control subjects. Hence it is suspected to induce toxicity in petroleum workers.
... According to Heibati's study http://eaht.org [39], workers exposed to BTEX from petroleum were investigated. Tanker loading workers were more exposed to benzene than office workers, both of which worked in the same work areas. ...
The purpose of this study was to compare the levels of acetylcholinesterase (AChE) among employees based on job positions and the wearing of personal protective equipment (PPE) in fuel station areas. The sample group consisted of 200 people sorted into various groups, including (i) Inside fuel dispenser area (I-FDA) group consisting of 100 employees for refueling, cashier, and loading fuel into storage tanks, and (ii) Outside fuel dispenser area (O-FDA) group, consisting of 100 employees working in convenience stores, food stores, coffee shops, and offices, as well as general staff and car washers. Data were collected using interview questionnaires and blood samples were analyzed for AChE activity. The results showed that the I-FDA group had a significantly lower mean of serum AChE (7.38±1.73 U/ml) than the O-FDA group (7.85±1.49 U/ml) ( p <0.05). The I-FDA group had a 2.43 times higher risk of abnormal serum AChE than the O-FDA group (OR=2.43, 95%CI=1.05-5.60). When considering the risk factors for job positions, it was found that refueling and cashier positions had lower AChE activity levels than those who did not ( p <0.05). In the part, employees for food sales in a closed building and those wearing PPE masks had significantly higher AChE activity levels than those who did not or who wore them ( p <0.05). Based on the aforementioned, employers at fuel stations should strictly determine the appropriate measures for wearing a PPE mask. Further, employees should be provided accommodation away from oil supply or enclosed buildings during breaks to reduce the effects on the neurotransmitter.
... Toluene and ethylbenzene can show toxicity, are capable to bioaccumulate in the human body, and cause damage to the central nervous system, and xylene causes skin and respiratory tract damage [13,14]. So, monoaromatic hydrocarbons' expected effect is neurotoxicity in the cases of their presence in the environment [15,16]. ...
The poor indoor air quality can be associated with the released volatile organic compounds (VOCs) from different sources. The extent of the concern may increase depending on the presence of benzene, toluene, ethylbenzene, and xylene (BTEX) and exposure to them in the indoor air. Adsorption with activated carbon, which is a very effective method, is preferred to eliminate highly volatile gaseous pollutants and reduce the extend of their negative impact. In this work, the removal efficiency of a novel activated carbons (MSRACs), prepared from stems of Corylus colurna (CCBW) by chemical processes using H2SO4, H3PO4, and HCl, was scrutinized towards BTEX pollutants. The adsorbents acquired from this lignin-based waste were investigated from porosity and surface chemistry aspects. The highest surface area of 1424 m²/g and micropore volume of 0.46 cm³/g were attained after activation of MSRAC11 adsorbent sample by H2SO4-70wt%. The performances of the fabricated adsorbent samples were evaluated and the order of MSRAC11>MSRAC24>MSRAC36 was obtained in the multiple concentrations of BTEX. This study introduces an easy method for producing efficient adsorbents from lignin-based waste for filtering indoor air and designing BTEX-capturing systems for various applications.
... Employees exposed to toluene gas for prolonged periods of time have been reported to suffer from neurological damage with symptoms such as headaches and drowsiness [7][8][9]. Short-term inhalation of high concentrations of toluene vapor can cause nausea, decreased vision, muscle cramps, dizziness, and even engenders permanent brain toxicity and death in severe cases [9][10][11][12]. For instance, the toluene detection limit required in the indoor air quality standard of China (IAQS, GB/T 18883-2002) is under 47 ppb [13]. ...
Rapid detection of low concentration toluene is highly desirable in environment monitoring, industrial processes, medical diagnosis, etc. In this study, we prepared the Pt-loaded monodispersed nanoparticles through hydrothermal synthesis and assembled a toluene sensor with fast response and low detection limits based on Micro-Electro-Mechanical System (MEMS). Compared with the pure SnO 2 , the 3 wt% Pt-loaded SnO 2 sensor exhibits a 2.75 times higher gas sensitivity to toluene gas at about 330 °C. Meanwhile, the 3 wt% Pt-loaded SnO 2 sensor also has a stable and good response to 100 ppb of toluene. Its theoretical detection limit was calculated as low as 12.6 ppb. Also, the sensor has a short response time of ~10 s at different gas concentrations (even down to 5.4 s at 20 ppm), as well as the excellent dynamic response-recover characteristic, selectivity, and stability. The improved performance of Pt-loaded SnO 2 sensor can be explained by the increase of oxygen vacancies and chemisorbed oxygen. In our MEMS sensors, three gas sensing elements could be packaged in one ceramic shell for parallel testing and made it easier for real application by embedding in a printed circuit board. This provides new ideas and decent prospect for developing miniaturized, low-power-comsumption, and portable application of gas sensing devices.
... However, it has been pointed out that evaluation by urinary metabolites makes it difficult to eliminate the effects of food intake, etc [7,8], and does not sufficiently reflect BTX exposure at extremely low pollution levels such as the general environment [9][10][11][12]. Therefore, headspace gas chromatography for unchanged BTX in blood and urine is useful [13][14][15][16][17]. This is a very specific indicator of exposure and is a good reflection of exposure to low concentrations. ...
Background: Benzene, toluene, and xylene (BTX) are ubiquitous in the community environment. However, workers who handle them are concerned about adverse effects such as neurotoxicity and carcinogenicity. On the other hand, recently, in a general indoor environment, low-concentration BTX exposure due to release from a house has attracted attention as a cause of sick building syndrome and multiple chemical sensitivity. In order to understand the exposure status of BTX, it is effective to measure the unchanged BTX in biological samples such as blood and urine. However, the burden on the subject when collecting samples cannot be ignored. Method: To generalize BTX measurement of biological samples in the field, the author has developed a syringe equilibrium / headspace gas chromatography using a small amount of biological sample and Portable GC and analytical accuracy was tested. Also, considering the case of bringing small samples back to the laboratory for analysis, ways to store biological samples containing BTX for extended periods of time was determined. And BTX contamination survey of newly built condominiums was conducted to verify the practicality. Result: The reproducibility of syringe equilibrium / headspace gas chromatography with standard -added blood. In all BTX, the relative standard deviation was found to be within 10%, and according to the internal standard method, the relative standard deviation was found to be within 5%. BTX contamination survey of newly built condominiums completed successfully. Benzene and toluene were detected in the urine of the resident, but only toluene was detected indoors. Conclusion: This method and the use of a portable GC with a photoionization detector enable assessment from microexposure in the living environment to occupational exposure levels with 50 μl microblood, reducing the burden on the subject. In addition, a long-term storage method of biological samples containing BTX, was developed to consider the case of bringing small samples back to the laboratory for analysis.
... Identifying the reversible action of chemical compounds on the human body is important in minimizing the risk of affecting human health. Biological monitoring is primarily based on the measurement of unmetabolized compounds or metabolites in urine or blood matrices (Heibati et al. 2018). Due to the strong relationship between the urinary un-metabolized BTEX and air levels of these compounds, urine has been recommended as a suitable and reliable biomarker in exposure assessment studies, especially for inhalation exposure at levels below 0.5 ppm (Rahimpoor et al. 2021, Rafiee et al. 2022). ...
Hookah smoking is one of the major indoor sources of benzene, toluene, ethylbenzene, and xylenes (BTEX). This study aimed to investigate the potential exposure to BTEX among primary school children, particularly those exposed to hookah smoke. This cross-sectional study was conducted in Khesht, one of the southwestern cities in Iran, in mid-June 2020. Totally, 50 primary school children exposed to hookah smoke were chosen as the case group and 50 primary school children were selected as the control group. Urinary un-metabolized BTEX was measured by a headspace gas chromatography mass spectrometry (GC–MS). Additionally, a detailed questionnaire was used to gather data and information from the students’ parents. The mean levels of urinary benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene were 1.44, 5.87, 2.49, 6.93, and 7.17 μg/L, respectively in the exposed children. Urinary BTEX was 3.93-folds higher in the case group than in the controls (p<0.05). Household cleaning products, the floor on which the house was located, children’s sleeping place, and playing outdoors were found to be important factors in predicting urinary BTEX levels. Overall, it was found necessary to avoid indoor smoking to prevent the emission of BTEX compounds via exhaled mainstream smoke and to protect vulnerable non-smokers, especially children, from exposure to second-hand and third-hand smoke.
... Factor 4 contributed aromatic hydrocarbons such as benzene (31.77%), toluene (29.97%) and ethylbenzene (16.73%), which can also be attributed to gasoline usage [53]. MTBE (33.37%) is a commonly used additive to improve gasoline octane number, which was also reflected in this factor [54]. 1,2-dichloroethane (40.03%), as a petroleum hydrocarbon pollutant, was also contributed in a high percentage [55,56]. ...
In recent years, the “coal to electricity” project (CTEP) using clean energy instead of coal for heating has been implemented by Beijing government to cope with air pollution. However, VOC pollution after CTEP was rarely studied in suburbs of Beijing. To fill this exigency, 116 volatile organic compounds (VOCs) were observed during nonheating (P1) and heating (P2) periods in suburban Beijing. The results showed that the total of VOCs (TVOCs) was positively correlated with PM2.5, PM10, NO2, CO, and SO2 but negatively correlated with O3 and wind speed. The average TVOCs concentration was 19.43 ± 12.41 ppbv in P1 and 16.25 ± 8.01 ppbv in P2. Aromatics and oxygenated VOCs (OVOCs) were the main contributors to ozone formation potential (OFP). Seven sources of VOCs identified by the positive matrix factorization (PMF) model were industrial source, coal combustion, fuel evaporation, gasoline vehicle exhaust, diesel vehicle exhaust, background and biogenic sources, and solvent usage. The contribution of coal combustion to VOCs increased significantly during P2, whereas industrial sources, fuel evaporation, and solvent usage exhibited opposite trends. The potential source contribution function (PSCF) and concentration weighted trajectory (CWT) were used to analyze the source distributions. The results showed that VOC pollution was caused mainly by air mass from southern Hebei during P1 but by local emissions during P2. Therefore, although the contribution of coal combustion after heating increased, TVOCs concentration during P2 was lower than that during P1. Chronic noncarcinogenic risks of all selected VOC species were below the safe level, while the carcinogenic risks of most selected VOC species were above the acceptable risk level, especially for tetrachloromethane and 1,2-dichloroethane. The cancer risks posed by gasoline vehicle emissions, industrial enterprises, and coal combustion should be paid more attention.
... Heibati et al evaluated the average exposure of workers in different stages of loading as well as tanks and transport drivers and firefighters and office workers and found that the highest concentration was related to workers loading in tankers, and the concentration of benzene was reported 5.390 mg/m 3 (39). The concentration of BTEX in station C in the present study is very close to that reported in this study. ...
Background: Fuel stations are one of the major sources of air pollution with volatile organic compounds, especially the four main petrol compounds benzene, toluene, ethylbenzene, and xylene (BTEX). BTEX in gasoline enters the air of gas stations due to high evaporation of gasoline. Therefore, determining the concentration of these compounds in gas stations in crowded and busy cities is one of the important priorities of environmental health, which is doubly important in terms of its negative effects on health.
Methods: In this descriptive cross-sectional study, a total of 39 samples were collected from 13 gas stations. Sampling was performed in autumn 2018 in three working shifts (morning, noon, and night). The method NIOSH-1501 (i.e., using charcoal sorbent tubes and SKC pump with a flow rate of 0.2 L/min) was used for sampling the BTEX compounds. The mean difference and correlation of BTEX compounds based on meteorological parameters and the number of nozzles in gas stations were assessed using one-way ANOVA and correlation tests.
Results: The mean and standard deviation of benzene, toluene, ethylbenzene, and xylene concentrations in the air of fuel stations were 2.784 ± 1.461, 3.495 ± 1.390, 2.091 ± 0.811, and 1.140 ± 0.419 mg/m3, respectively. The relationship between BTEX compounds and meteorological parameters such as humidity and exposure time is very important. There is a strong correlation between the concentrations of BTEX compounds. The highest correlation was observed between benzene and toluene and the lowest one was observed between benzene and xylene. In this study, no significant relationship was
observed between air temperature and concentration of BTEX compounds, but there was a relationship between relative humidity and the concentration of BTEX compounds.
Conclusion: The average benzene concentration in the air at the fuel stations was about 5.5 times the standard limit. Authorities should improve fuel quality and reduce its evaporation through engineering measures to overcome the issue.
... These are the socalled bottom sediment erosion systems. If these systems do an excellent job in the daily operation of oil reservoirs, then we can assume that it will also be effective in case of fires, contributing to the destruction of not only the homothermal layer, but also the layer with bottom water, mixing them [22]. ...
The main reasons for the occurrence of oil outbursts from burning reservoirs are considered. To prevent the release of oil from a burning reservoir, they must be forced and intensively mixed using bottom sediment systems. Measures for pumping oil from burning reservoirs are proposed.
... It can be found that workers at the coal charging workshop and near coke ovens may suffer from a higher BTEX exposure than those in offices. Compared with BTEX concentrations in the other occupational exposure scenarios reported abroad, the concentration in this research was much higher than data reported at a gas station in Porto, Portugal with BTEX concentration 15.3 µg m −3 , comparable with tank-gauging workers (830 µg m −3 ), but higher than drivers (81.9 µg m −3 ), firefighters (71.2 µg m −3 ) and office workers (19.8 µg m −3 ) in Iran[47]. ...
Benzene, toluene, ethylbenzene and xylene isomers (BTEX) have raised increasing concern due to their adverse effects on human health. In this study, a coking factory and four communities nearby were selected as the research area. Atmospheric BTEX samples were collected and determined by a preconcentrator GC–MS method. Four biomarkers in the morning urine samples of 174 participants from the communities were measured by LC–MS. The health risks of BTEX exposure via inhalation were estimated. This study aimed to investigate the influence of external BTEX exposure on the internal biomarker levels and quantitatively evaluate the health risk of populations near the coking industry. The results showed that the average total BTEX concentration in residential area was 7.17 ± 7.24 μg m−3. Trans,trans-muconic acid (T,T-MA) was the urinary biomarker with the greatest average level (127 ± 285 μg g−1 crt). Similar spatial trends can be observed between atmospheric benzene concentration and internal biomarker levels. The mean values of the LCR for male and female residents were 2.15 × 10−5 and 2.05 × 10−5, respectively. The results of the risk assessment indicated that special attention was required for the non-occupational residents around the area.
... Non-occupational factors that may contribute to BTX exposure are smoking cigarettes, diet ( sh, nuts, alcoholic drinks, poultry and offal); paint and consumer products (glues, adhesives, lacquers, waxes, detergents and cleaning products); tra c intensity (car exhaust emissions, type of fuel, age and type of motor vehicle, speed rate). Petrol stations, electronic devices (printer/photocopiers), some furniture (chair/tables) and infrastructure at new buildings also emit BTX s (22,23). ...
Biomonitoring of exposure to benzene, toluene and xylene (BTX) was conducted in a group of 29 petroleum refinery workers in South Africa. Post shift urine samples from 21 males and 8 females over a period of four years (2010 to 2013 inclusive) were received from one petroleum refinery. The samples were analysed using high performance liquid chromatography with diode array detection and liquid-liquid extraction followed by gas chromatography-mass spectrometry for phenol, o-cresol and methylhippuric acid which are biomarkers of exposure to benzene, toluene and xylene, respectively.
Benzene and xylene results were well within the recommended exposure levels with the exception of one worker in 2013 with an elevated phenol exposure level. A few workers (< 40%) were found to be randomly overexposed to toluene, with 17% of the workers exhibiting higher than the biological exposure index. No difference was observed in exposure with regard to age and gender (p>0.05), except in 2012 where females were more exposed to benzene than their male counterparts (p=0.003). Differences in exposure were found among the three exposure categories (low, medium and high exposure), for both xylene and benzene exposure in 2010 and 2011, respectively. Friedman’s ANOVA showed that over the four years of monitoring, the workers were exposed to variable levels of BTX (p < 0.05).
Random individual overexposure to toluene and an anomaly for benzene were noted. Biomonitoring of petroleum workers and proper assessment of the health risks and planning for adequate health protection are highly recommended for this group of workers.
... That study showed concentrations of toluene exposure lower than the Iranian OEL recommendation and similar to those of the refueling workers at Thai gasoline stations (Hazrati et al. 2016). When comparing to studies on other occupations, such as Italian traffic policemen who had been exposed to benzene at 2.79 ± 0.75 ppb (Gromadzinska and Wasowicz 2019), and the tanker driver in Iran exposed to benzene at 25.64 ± 6.35 ppb and toluene at 156.64 ± 80.32 ppb (Heibati et al. 2018), it can be seen that those workers who were exposed to benzene and toluene in areas outside the gasoline station had lower concentrations. In addition, the results confirm that workers at gasoline stations had higher levels of benzene and toluene exposure than unexposed workers (office workers) (Xiong et al. 2016). ...
This cross-sectional study aimed to assess the adverse effects of benzene and toluene exposure in gasoline station workers via biological screening and health risk assessment. Ambient air benzene and toluene concentrations were monitored and analyzed by gas chromatography (GC-FID). Urinary samples to test trans,trans-muconic acid (tt-MA) and hippuric acid levels were collected after shift work from 158 refueling workers and 34 cashiers; any adverse symptoms were noted in the interview and hazard index (HI) values were estimated for workers’ adverse effects. There was a significant correlation between benzene and toluene concentrations at gasoline stations (r = 0.827). The levels of detected tt-MA and hippuric acid, metabolites of benzene and toluene, respectively, were higher in refueling workers (IQR = 537.88 µg/g creatinine (Cr), 316.41 mg/g Cr) than in cashiers (IQR = 208.68 µg/g Cr, 236.17 mg/g Cr). The concentrations of benzene and locations of stations were associated with detection of tt-MA. Adverse symptoms of benzene and toluene exposure, i.e., sore throat, drowsiness, muscle weakness, and unconsciousness were reported. The hazard index values from exposure to benzene and toluene among refueling workers were found to have statistical significance. The conclusion is that carrying out health surveillance with benzene exposure monitoring and health screening can be an important aspect of a strategy to reduce toluene exposure in gasoline workers.
... Вредные факторы производственной среды могут не только быть причиной профессиональных патологий, но и влиять на сроки развития и прогрессирование общих заболеваний, не относящихся к профессиональным. Изменения величины профессионального риска, проводимые на базе эволюционных моделей у работающих с течением времени [14], позволяют спрогнозировать отдаленные последствия, связанные с воздействием производственных факторов [15]. Максимальный риск развития профессиональной патологии отмечался у мужчин при экспозиции к общей вибрации (ОР = 39,88; ДИ 14,92-106,61), который превышал риск, возникающий при воздействии шумового фактора (ОР = 22,44; ДИ 9,27-54,32). ...
Background: Improvement of working conditions at enterprises of various sectors of economy can be achieved by solving comprehensive organizational, social, legal and other tasks. The purpose of the research was to study working conditions and occupational morbidity of workers of various industries in the Republic of Bashkortostan in 2000–2019. Materials and methods: We analyzed working conditions of the population employed at the enterprises of the republic and occupational disease rates. Results: Most occupational risk factors were attributed to imperfection of technological processes, equipment and design flaws of machines, mechanisms, equipment, devices and tools. More than a third of cases of occupational disorders were diseases of the musculoskeletal system while every fifth case was that of a respiratory disease; radiculopathy and vibration disease prevailed among nosological forms. Men exposed to general vibration were most at risk of developing occupational diseases, including those induced by other occupational risk factors. At enterprises of mining, construction, and manufacturing industry, working conditions usually failed to meet sanitary and hygienic requirements for physical work heaviness, noise and chemical exposures, in agriculture – for physical work heaviness, and in transport and communications – for work heaviness and intensity. Conclusion: We observed a steady increase in the proportion of employees exposed to occupational risk factors and/or hazards and a simultaneous decrease in registered occupational disease incidence rates.
... Biological monitoring of BTEXs is more critical than monitoring them in ambient air because identifying biomarkers can detect individual exposure to predetermined pollutants and prevent their reversible effects (Heibati et al., 2018). In this regard, biological monitoring in workplaces can reduce community health risks and prevent diseases caused by BTEX exposure (Cherrie et al., 2006;Jakubowski, 2012;Maurizio Manno et al., 2010;Semple, 2004). ...
The biomarker analysis of benzene, toluene, ethylbenzene, and xylene (BTEX) in biological samples is the primary technique for evaluating these compounds in occupational and environmental exposures. The BTEX biomarkers are widely used to study the BTEX distribution in the environment and workplaces. Liquid‐liquid extraction and solid‐phase liquid extraction are among the most commonly used conventional methods to analyze biological indices of BTEX. New methods have been proposed to analyze BTEX biomarkers using novel adsorbents such as sol‐gel composite nanotubes, molecularly imprinted polymers, and metal‐organic frameworks, which are based on applications of needle trap devices, microextraction by packed sorbent, and solid‐phase microextraction techniques. This paper was an overview of new methods since 2015 regarding applying microextraction methods based on new adsorbents and analyzing BTEX biomarker compounds for occupational and environmental exposures. The results were compared with the liquid phase microextraction methods recommended for urinary BTEX biomarkers.
... In the case of benzene, we recommend to determine it as the BTEX (benzene, toluene, ethylbenzene, and xylene) metabolite complex, which has been used as a biomarker found in urine in petroleum distribution facilities (44). To assess exposure to PAH, it is valuable to use 1-OHP, which is the most commonly used PAHs biomarker in both work and living environments (45). ...
Ida-Viru County, in Eastern Estonia, features industrially contaminated sites–where oil shale has been mined and used for electricity generation, and shale oil extraction. Higher prevalence of respiratory and cardiovascular disease has been found in the region due to high quantities of air pollution. Within the framework of “Studies of the health impact of the oil shale sector—SOHOS,” this analysis aimed to map earlier human biomonitoring (HBM) studies and identify the suitable biomarkers for upcoming HBM in Estonia. Altogether, three studies have been conducted among residents: first, among adults in the 1980's; second, among children in the 1990's; and third, among employees, with a focus on workers and miners in the oil shale chemistry industry in the late 1990's and 2000's. In some of those studies, increased levels of biomarkers in blood and urine (heavy metals, 1-OHP) have appeared; nevertheless, in last 20 years, there has been no population-wide HBM in Estonia. According to air pollution monitoring and emission analysis, the pollutants of concern are benzene, PM10, PM2.5, and PAHs. In general, there is a decreasing trend in air pollutant levels, with the exception of a slight increase in 2018. One of the aims of HBM is to be analyzed if this trend can be identified in HBM, using similar biomarkers as applied earlier. The future perspective HBM could be divided into two Tiers. Tier 1 should focus on exposure biomarkers as heavy metals, PAH, and BTEX metabolites and Tier 2, in later stage, on effect biomarkers as Ox LDL, TBARS, etc.
... Our results showed higher urinary BTEX levels in exposed subjects who were nonsmokers than smokers in the control group, which indicates that exposure to BTEX compounds in the case subjects could be comparable with the one resulting from smoking which reported in previous studies . However, in a study carried out among workers at petroleum distribution facilities, no significant differences of urinary BTEX levels were reported between smokers and non-smokers which are inconsistent with the findings of the present study (Heibati et al. 2018). One of the possible reasons could be due to this fact that there are stronger BTEX emission sources in the occupational context, which reduce the effect of smoking. ...
Urinary benzene, toluene, ethylbenzene, and xylenes (BTEX) can be used as a reliable biomarker of exposure to these pollutants. This cross-sectional study aimed to employ biomonitoring to assess BTEX exposure among South Pars Gas Field (SPGF) workers in Assaluyeh, Iran. 40 employees who were working on the site were recruited as the case group. Besides, 31 administrative employees were recruited as the control group. Pre-shift and post-shift spot urine samples were collected from the subjects in the case group, while the subjects in the control group provided mid-morning urine samples. Overall, 111 urine samples, including 80 samples from the case group and 31 samples from the controls, were collected. Gas Chromatography-Mass Spectrometry (GC/MS) was used to determine the urinary levels of BTEX compounds. The median urinary levels of benzene, toluene, ethylbenzene, m-p xylene, and o-xylene in the post-shift samples of the exposed group were 1.24, 2.28, 0.5, 1.32, and 1.5 µg/l, respectively. Significant differences were observed in urinary BTEX levels among smokers and non-smokers in both studied groups (p<0.05). Accordingly, the median urinary BTEX concentrations in smokers were 2 to 6.5times higher than the corresponding values in non-smokers subjects. Smoking status was the only predictor of the urinary BTEX concentration. Our findings revealed that refinery workers are exposed to significant levels of BTEX compounds. Considering the health risks associated with BTEX exposure for refinery workers, implementation of suitable control strategies, such as using appropriate personal protective equipment and improving on-site ventilation systems, are recommended reducing their exposure to BTEX via the inhalation.
... The important characteristic of VOCs is toxicity, and some VOCs are toxic for human and animals [10]. Representative toxic VOCs are benzene, toluene, ethylbenzene, and xylene in the aromatic family [11][12][13]. Benzene is classified as a class 1 carcinogen by the World Health Organization (WHO) and the International Agency for Research (IARC) [14]. ...
This paper presents the combustion and emissions characteristics including volatile organic compound (VOC) of a common rail direct injection diesel engine fueled with palm oil biodiesel blends contained 0%, 10%, 30%, and 100% (by volume) biodiesel at low idle speed, i.e., 750 rpm. The nitrogen oxide (NOx) emissions of biodiesel blends were lower than that of pure diesel and NOx tended to decrease as the blending ratio increased. Soot opacity and hydrocarbon (HC) were reduced with an increasing blend ratio. Carbon monoxide (CO) varied with the engine load conditions. Under low load, CO emissions tended to decrease with increasing blending ratio and increased under high load. Alkane and aromatic VOCs were mostly emitted. Benzene and tetrahydrofuran accounted for the largest percentage of total detected VOCs in all test conditions. Benzene, toluene, ethylbenzene, xylene (BTEX, toxic aromatic VOCs) were detected for all tests. Among BTEX, benzene has the highest emission ratio, followed by xylene, toluene, and ethylbenzene. Benzene increased for all tests. At low engine load, toluene, ethylbenzene, and xylene decreased with increasing blend ratio. However, these increased at high engine load. When pure palm oil biodiesel was applied at high engine load, benzene decreased.
... Typical biological matrices used for human biomonitoring are blood and urine, both for assessing occupational scenarios [7,8] and the general population [9][10][11]. In the last few decades, scalp hair has become an interesting bioindicator in various disciplines, such as the biological, medical, environmental, and forensic fields [12][13][14]. ...
The aim of the study was to evaluate occupational exposure to 40 elements among a group of Eritrean adults employed at the Medeber metal market by analysing human scalp hair samples and by investigating the role of some predictors (gender, age, and body mass index—BMI) on their levels. Scalp hair samples were collected from 60 subjects (32 subjects working at the Medeber metal market and 28 subjects not working at Medeber and not employed in other industrial or artisanal activities) and were analysed through inductively coupled plasma mass spectrometry to determine the contents of 40 major and trace elements. Information on participants was collected via questionnaire. Significant differences were found in the hair levels of certain elements between subjects working at the Medeber metal market and subjects not exposed. In particular, working at the Medeber metal market increased hair levels of Be, B, Cu, Zn, Mo, Cd, Sb, Tl, Pb, and Fe from 25 to 100%, while reduced Na, K, and Rb levels from 30 to 50%. With multivariate adjustment for age, gender, and BMI, the results confirm that working at Medeber significantly increased the hair levels of Cu, Zn, Sb, Pb, and Fe. This finding reveals the need for more accurate and routine biomonitoring surveys and the necessity of health promotion campaigns both for local decision-makers and workers to increase health promotion and safety in this workplace.
... On the territory of the oil filling station, samples of the upper soil layer were taken and chemical analysis was carried out [9,10] (Table 3). Based on the results of the survey of the OFS territory, it was proposed to cut grass near the underground tanks and within the protected zones in early June, i.e. before insemination of dandelions and other ripening herbs. ...
The article studies the ecological state of the territory of Novoselki OFS and adjacent territories. The situational analysis of the territory was carried out. Its results will be applied in the section “Ecology and development of an ecological passport of the industrial enterprise”. Practical recommendations on greening and reducing the fire risk were provided.
To monitor employees' work safety and exposure against air contaminants, Trans, trans-muconic acid, Hippuric acid, Methyl hippuric acid, Mandelic acid and Phenylglyoxylic acid can be used as reliable biomarkers of exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. This study aims to determine the level of urinary metabolites of BTEX compounds using biological monitoring in the employees of a wastewater treatment plant (WWTP) in the south of Iran. The study was performed on 56 employees of the WWTP of one of the southern cities of Iran in 2020. Urine samples (n total = 112) consisting of 60 samples of employees working in the operation section (exposed group) and 52 samples of employees working in the administrative section (control group) in the WWTP were collected before and at the end of their shift. The mean concentration of urinary metabolites of BTEX of both groups ranged from 546.43 (μg/g cr) for trans, trans-muconic acid to 0.006 (μg/g cr) for methyl hippuric acid, which indicates that most of the evaluated metabolites showed a higher concentration than their occupational threshold limit value urine (p < 0.05). Regression analysis results showed a significant correlation (p < 0.05) between age and utilization of flame heaters with changes in the measured BTEX metabolites in the urine. The results of this study illustrate that WWTPs should be considered as one of the workplaces with potential sources of BTEX exposure for employees. Future investigations are recommended to perform itemized appraisals of BTEX intake sources, particularly in employees of the operational sections of WWTP.
The human body secretes a complex blend of volatile organic compounds (VOCs) via the skin, breath and bodily fluids, the study of which can provide valuable insight into the physiological and metabolic state of an individual. Methods to profile human-derived volatiles typically source VOCs from bodily fluids, exhaled breath or skin of isolated body parts. To facilitate profiling the whole body volatilome, we have engineered a sampling chamber that enables the collection and analysis of headspace from the entire human body. Whole body VOCs were collected from a cohort of 20 humans and analyzed by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) to characterize the compounds present in whole body headspace and evaluate chemical differences between individuals. A range of compounds were detected and identified in whole body headspace including ketones, carboxylic acids, aldehydes, alcohols, and aliphatic and aromatic hydrocarbons. Considerable heterogeneity in the chemical composition of whole body odor and the concentration of its constituent compounds was observed across individuals. Amongst the most common and abundant compounds detected in human whole body odor were sulcatone, acetoin, acetic acid and C6-C10 aldehydes. This method facilitates standardized and quantitative analytical profiling of the human whole body volatilome.
Geothermal, contaminants, Organic pollutants, Thermophiles, Xylenes. Studies on organic pollutants in geothermal environments have received little attention; hence this review is necessary. The presence of trace organic pollutants such as benzene and xylenes has been reported as some of the main sources of pollution in geothermal systems. Previous studies using quantitative fluid inclusion gas analysis, Fischer-Tropsch Type (FTT) experiments and Gas chromatography-Mass spectrometry (GC-MS) have shown that there is a considerable presence of organic pollutants such as trace mono aromatic hydrocarbons (MAHs), polycyclic aromatic hydrocarbons (PAHs), and emerging organic contaminants whose origin is both biogenic and abiogenic. Organic pollutants were initially not considered in geothermal development and utilization despite the fact that these toxic chemicals can precipitate severe ecological poisoning and potential risks to human health and aquatic life in a given geothermal environment, even at very low concentrations. The significant presence of benzene in various geothermal systems is of concern because it is a precursor for many aromatic compounds that are bio-accumulative and toxic to water regimes and the environment. Thermophilic and mesophilic bacteria, nonetheless, play a critical role during the biodegradation of organic pollutants in geothermal regimes. From the findings of this review, it is difficult to classify geothermal energy exploitation and utilization as an environmentally benign resource.
The aim of introducing occupational exposure limits (OELs) is to use them as a risk management tool in order to protect workers’ health and well-being against harmful agents at the workplace. In this review we identify OELs for benzene, toluene, ethylbenzene, xylene (BTEX), and styrene concentrations in air and assess occupational exposure to these compounds through a systematic literature search of publications published in West Asian countries from 1980 to 2021. OELs for BTEX and styrene have been set in Iran and Turkey to levels similar to those in European countries and the US. The search yielded 49 full-text articles that cover studies of exposure assessment in six countries, but most (n=40) regard Iran. Average occupational exposure to benzene of workers in oil-related industries is higher than recommended OEL, while average occupational exposure to other compounds is lower than local OELs (where they exist). Currently, information about levels of occupational exposure to BTEX and styrene is insufficient in West Asian countries, which should be remedied through OEL regulation and application. Furthermore, coherent research is also needed to determine actual levels of occupational exposure, doseresponses, and the economic and technical capacity of local industries to address current issues.
Keywords
benzene, ethylbenzene, OEL, oil industry, risk management, toluene, xylene
Hazardous organic compounds such as benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene (known as BTEX) found at work and at home can cause adverse health effects of human beings throughout their lives. Biological monitoring, an exposure assessment method, considers all exposed organic and non-organic compounds. Our goal was to perform a systematic review and a statistical analysis (meta-analysis) of peer-reviewed publications to assess urinary concentrations of BTEX biomarkers in both occupationally-exposed population and the general population. Several major electronic databases, including Scopus, Embase, Medline, Web of Science, and Google scholar (grey literature), were searched for biomonitoring studies of BTEX. Overall, 33 studies met the eligible criteria for the systematic review and six met the full inclusion criteria for meta-analysis. For meta-analysis, we included studies in which unmetabolized BTEX compounds were measured in urine samples. Due to insufficient data, studies that measured BTEX metabolites in urine samples and unmetabolized BTEX compounds in blood samples were excluded from the meta-analysis but were analyzed in the qualitative synthesis. Most studies showed increased urinary concentrations of BTEX in exposed individuals (mainly workers) compared to unexposed individuals. The results showed that the highest total BTEX concentrations were recorded in painters and policemen. This study showed that the undoubted associations between lifestyle and environmental factors and urinary levels of BTEX or its metabolites have not yet been confirmed in current biomonitoring studies. This is attributed to the few studies reported in this research area, the lack of homogeneous information, and the disagreement in the published results of the studies.
Diesel engines are important emission sources of aromatic Volatile Organic Compounds species including Benzene, Toluene, Ethylbenzene and o, m, p Xylene (BTEX). In this study,the impact of aromatic VOCs emission from diesel engines operation was investigated in a local food market. The aim of this study was to assess the contribution of diesel engines to VOCs emission in a local food processing market, Ago, Ilorin, Nigeria, on workers, patronizers and inhabitants. Fabricated passive samplers were deployed at ten locations for both indoor and outdoor within the market at above 1.5m human breathing height containing 30gramms of activated charcoal each as adsorbent. The samplers were exposed for one month, the analytes were recovered by desorption process with carbondisulphide CS2 and subjected to Gas Chromatography fitted with flame ionization detector. The VOCs concentrations found are ranged from 0.0021-0.0026 mg/m3 for Benzene; 0.0017-0.0023mg/m 3 for Toluene; 0.0009-0.0017 mg/m 3 for Ethylbenzene;0.00101-0.00192 mg/m 3 for Xylene for outdoor sampling while for indoor sampling the ranged are 0.0024-0.0031 mg/m 3 for Benzene; 0.0018-0.0023 mg/m 3 for Toluene; 0.0013-0.0023 mg/m 3 for Ethylbenzene;0.00093-0.00222 mg/m 3 for Xylene. The averaged BTEX concentration at the indoor was higher than outdoor environment. The averaged concentrations of BTEX at all locations were lower than the limit of air quality standards. The mean lifetime cancer risk for workers, patronizers and inhabitants exposed to benzene and ethylbenzene for 25 years were estimated at 1.33x10-7 and 1.16x10-7 for indoor and outdoor respectively. Non cancer risks Hazard Index were estimated to be 1.11x10-5 and 8.74x10-6 for both indoor and outdoor respectively. Both cancer risk and non-cancer risk assessment are within acceptable limit. This study established that significant aromatic VOCs are emitted from diesel engine exhausts and recommends hydrogen powered engines in place of diesel engines as to eliminate VOC emissions in local food processing industries.
Benzene, a ubiquitous environmental chemical, is known to cause immune dysfunction and developmental defects. This study aims to investigate the relation between benzene‐induced immune dysfunction and developmental toxicity in a genetically tractable animal model, Drosophila melanogaster. Further, the study explored the protective role of Heat Shock Protein 70 (Hsp70) against benzene‐induced immunotoxicity and subsequent developmental impact. Drosophila larvae exposed to benzene (1.0, 10.0, and 100.0 mM) were examined for total hemocyte (immune cells) count, phagocytic activity, oxidative stress, apoptosis, and their developmental delay and reduction were analyzed. Benzene exposure for 48 h reduced the total hemocytes count and phagocytic activity, along with an increase in the Reactive Oxygen Species (ROS), and lipid peroxidation in the larval hemocytes. Subsequently, JNK‐dependent activation of the apoptosis (Caspase‐3 dependent) was also observed. During their development, benzene exposure to Drosophila larvae led to 3 days of delay in development, and ~40% reduced adult emergence. Hsp70‐overexpression in hemocytes was found to mitigate benzene‐induced oxidative stress and abrogated the JNK‐mediated apoptosis in hemocytes, thus restoring total hemocyte count and improving phagocytotic activity. Further, hsp70‐overexpression in hemocytes also lessened the benzene‐induced developmental delay (rescue of 2.5 days) and improved adult emergence (~20%) emergence, revealing a possible control of immune cells on the organism's development and survival. Overall, this study established that hsp70‐overexpression in the Drosophila hemocytes confers protection against benzene‐induced immune injury via regulating the ROS/JNK signaling pathway, which helps in the organism's survival and development.
Volatile organic compounds (VOCs) play an important role in the formation of ground-level ozone and secondary organic aerosol (SOA), and they have been key issues in current air pollution prevention and control in China. Considerable attention has been paid to industrial activities due to their large and relatively complex VOCs emissions. The present research aims to provide a comprehensive review on whole-process control of industrial VOCs, which mainly includes source reduction, collection enhancement and end-pipe treatments. Lower VOCs materials including water-borne ones are the keys to source substitution in industries related to coating and solvent usage, leak detection and repair (LDAR) should be regarded as an efficient means of source reduction in refining, petrochemical and other chemical industries. Several types of VOCs collection methods such as gas-collecting hoods, airtight partitions and others are discussed, and airtight collection at negative pressure yields the best collection efficiency. Current end-pipe treatments like UV oxidation, low-temperature plasma, activated carbon adsorption, combustion, biodegradation, and adsorption-combustion are discussed in detail. Finally, several recommendations are made for future advanced treatment and policy development in industrial VOCs emission control.
Single-chemical thresholds cannot comprehensively evaluate the risk of chemical mixture exposure in indoor air. Moreover, a large number of researches have focused on short-term and high-concentration co-exposure scenarios related to different species, based on diverse endpoints, which hampers the application and improvement of existing risk evaluation models of chemical mixture exposures. More importantly, current risk evaluation models are not user-friendly for construction practitioners who do not have sufficient toxicological knowledge. Therefore, in this study, an inhalation experiment system and a hazard index (HI) were developed to investigate the risks associated with low-concentration and long-term inhalation exposure scenarios of formaldehyde and benzene, individually and combined, based on Drosophila melanogaster mortality. The results showed that the system exhibited good reproducibility in providing stable exposure concentrations during D. melanogaster life cycle. Furthermore, in a range of experimental concentrations, the interaction between formaldehyde and benzene was additive or synergistic, which was concentration- and ratio-dependent. This study is of great significance in harmonising and providing toxicity data under long-term and low-concentration exposure scenarios, which is beneficial for establishing a new user-friendly risk evaluation model for indoor chemical mixture exposures. It should be noted that the proposed HI value could indicate the hazard degrees of long-term inhalation exposures of formaldehyde and benzene, individually and combined, to D. melanogaster. However, the applicability of this index requires further experiments to evaluate the exposure risks of other volatile organic compounds (VOCs) to D. melanogaster.
Benzene, toluene, ethylbenzene, and xylenes (BTEX) released from landfills have received increased attention because of their health risks. In this study, individual external and internal exposures of BTEX in a municipal solid waste (MSW) landfill were simultaneously studied for the first time. Eight workers from the landfill (as the case group) and eight control subjects were enrolled in the study. In total, 88 air samples and 232 urine samples (194 samples from the case group and 38 samples from the control group) were obtained from 2018 to 2019. According to the results of external exposure monitoring, benzene was the predominant component of BTEX, and the exposure level was higher in winter than in other seasons. Carcinogenic (RiskT) and noncarcinogenic (HIT) risks were calculated based on a dose-response model. The RiskT (1.64 × 10⁻⁸–1.09 × 10⁻⁶) might exceeded the limit, whereas HIT (9.84 × 10⁻⁴–1.40 × 10⁻²) was within their thresholds. Benzene was the major contributor to both RiskT and HIT. Internal exposures were evaluated by measuring urinary metabolites of BTEX. Levels of urinary BTEX metabolites for case group were higher than those for control group. A remarkable increase in urinary metabolites was observed from the urine samples of the case group after their shift compared with those before their shift. t,t-MA, the metabolite of benzene, was found to exceed the biomonitoring guidance limits of both China and the United States of America. Landfills can be considered as a potential BTEX exposure source for landfill employees. Minimizing occupational exposures and appropriate personal protective equipment are needed in reducing BTEX exposures.
Quantification of hippuric acid and methylhippuric acid in human urine matrices provides information on the toluene and xylene exposure conditions. High performance liquid chromatography coupled with UV detection is the preferable technique for hippuric acid and methylhippuric acid detection in human urine. This study was conducted to present analytical techniques developed for monitoring of hippuric acid and methylhippuric acid in human urine matrices during 2016–2021.
Children are highly susceptible to environmental contaminants as their physiology and some metabolic pathways differ from adults. The present cross-sectional study aimed to assess whether exposure to benzene, toluene, ethylbenzene, o,p-xylene, and m-xylene (BTEX) affects oxidative DNA damage in street children using a biomonitoring approach. Thirty-five boys (7–13 years of age), exposed by working at a busy intersection, and 25 unexposed boys of similar age and living in the neighborhood near the busy intersection were recruited. Urinary un-metabolized BTEX levels were quantified by a headspace gas chromatography-mass spectrometry (GC–MS). Urinary malonaldehyde (MDA) was measured with spectrophotometry. Sociodemographic and lifestyle conditions information was collected by interviews using administered questionnaires. Exposed subjects provided urine before (BE) and after work exposure (AE), while unexposed boys gave a single morning sample. Urinary BTEX concentrations in BE samples were similar to unexposed. Concentrations in AE samples were 2.36-fold higher than observed in BE samples (p < 0.05) and higher than those in the unexposed group (p < 0.05). In addition, urinary MDA levels in AE samples were 3.2 and 3.07-times higher than in BE samples and in the unexposed group (p < 0.05). Environmental tobacco smoke (ETS) increased urinary BTEX and MDA levels in both groups. Our findings confirm that street children working at busy intersections are significantly exposed to BTEX, which is associated with oxidative stress. Implementing protective measures is crucial to reduce exposure and to improve health outcomes in this group.
Zhengzhou is one of the most haze-polluted cities in Central China with high organic carbon emission, which accounts for 15%-20% of particulate matter (PM2.5) in winter and causes significantly adverse health effects. Volatile organic compounds (VOCs) are the precursors of secondary PM2.5 and O3 formation. An investigation of characteristics, sources and health risks assessment of VOCs was carried out at the urban area of Zhengzhou from 1st to 31st December, 2019. The mean concentrations of total detected VOCs were 48.8 ± 23.0 ppbv. Alkanes (22.0 ± 10.4 ppbv), halocarbons (8.1 ± 3.9 ppbv) and aromatics (6.5 ± 3.9 ppbv) were the predominant VOC species, followed by alkenes (5.1 ± 3.3 ppbv), oxygenated VOCs (3.6 ± 1.8 ppbv), alkyne (3.5 ± 1.9, ppbv) and sulfide (0.5 ± 0.9 ppbv). The Positive Matrix Factorization model was used to identify and apportion VOCs sources. Five major sources of VOCs were identified as vehicular exhaust, industrial processes, combustion, fuel evaporation, and solvent use. The carcinogenic and non-carcinogenic risk values of species were calculated. The carcinogenic and non-carcinogenic risks of almost all air toxics increased during haze days. The total non-carcinogenic risks exceeded the acceptable ranges. Most VOC species posed no non-carcinogenic risk during three haze events. The carcinogenic risks of chloroform, 1,2-dichloroethane, 1,2-dibromoethane, benzyl chloride, hexachloro-1,3-butadiene, benzene and naphthalene were above the acceptable level (1.0 × 10⁻⁶) but below the tolerable risk level (1.0 × 10⁻⁴). Industrial emission was the major contributor to non-carcinogenic, and solvent use was the major contributor to carcinogenic risks.
Operations and processes in the oil and gas industry have hazardous chemicals. Hence the possibility of having a work accident is high. Chemicals that exist are produced by activities related to the oil and gas industry processes, one of which is benzene. Because it has a severe impact on occupational health and safety, benzene exposure must be measured. Measurements were run through risk analysis to assess Hazard Index (HI) and make predictions of benzene exposure by focusing on the characteristics of workers, which can worsen the effect of the exposure. This study elaborated on several workers’ characteristics from a literature study’s human factors point of view. These characteristics were smoking, age, type of task, personal protective equipment use, exposure duration, regulations, hand washing habits, length of exposure, and nutritional status. Literature study results showed that regulatory characteristics, handwashing habits, and length of exposure were worsening the benzene exposure to workers. The other factors were in between agreed and disagreed in worsening the benzene exposure. These results perform as a base study in the further benzene analysis of oil and gas end distributor.
Sample preparation is one of the crucial steps in the analytical chemistry including human biomonitoring studies. Although, there are several traditional approaches available, solid-phase microextraction is emerged as one of the pioneering techniques due to its simplicity, rapidness, wide applicability, and miniaturization of traditional sample preparation (e.g., use of less or no organic solvents). There are few earlier review articles available on the advancements in solid-phase microextraction and its use for the measurement of environmental chemicals in various types of environmental samples. However, a collective information on applicability and current usage of solid-phase microextraction for the human biomonitoring of environmental chemicals are scarce nonetheless rising demands on innovative analytical approaches for human biomonitoring studies. Hence, in this review article, we covered the application of solid-phase microextraction extraction/purification methods for more than 15 classes of environmental chemicals to assess their respective exposure levels and associated health outcomes in various human population reported across the globe. Further, a detailed discussion on various types of matrix used, nature of coupled analytical instrumentations, and limitations and future perspectives of solid-phase microextraction for human biomonitoring studies is presented in this review.
Background: The analysis of temporal changes in the value of occupational risk for workers based on evolutionary models helps predict long-term effects of occupational factors and develop effective preventive measures. The objective of our study was to test application of evolutionary modeling to assessing the relationship between prevalence rates of occupational and occupation-related diseases in workers induced by various factors of occupational environment and work processes. Materials and methods: We made epidemiological assessment of the association between workers’ health and working conditions in compliance with the requirements of Guidelines R 2.2.1766–03. The parameters of paired mathematical models constructed for different exposure levels were used for risk evolution models accounting for accumulation of functional changes attributed to external causes. Results and discussion: The results of risk evolution modeling showed that 20 years of high occupational noise exposures exceeding the maximum permissible level posed a very high risk of developing sensorineural hearing loss by the age of 48, this risk being high and moderate in the age ranges of 36–47 and 24–35, respectively. According to the same model, 20-year-long high occupational vibration exposures exceeding the maximum permissible level posed a moderate risk of developing diseases of the musculoskeletal system and connective tissue in workers aged 46–65. The risk of developing diseases of the nervous system posed by xylene exposures below the maximum permissible level was assessed as negligible.
Shijiazhuang, the city with the worst air quality in China, is suffering from severe ozone pollution in summer. As the key precursors of ozone generation, it is necessary to control the Volatile Organic Compounds (VOCs) pollution. To have a better understanding of the pollution status and source contribution, the concentrations of 117 ambient VOCs were analyzed from April to August 2018 in an urban site in Shijiazhuang. Results showed that the monthly average concentration of total VOCs was 66.27 ppbv, in which, the oxygenated VOCs (37.89%), alkanes (33.89%), and halogenated hydrocarbons (13.31%) were the main composite on. Eight major sources were identified using Positive Matrix Factorization modeling with an accurate VOCs emission inventory as inter-complementary methods revealed that the petrochemical industry (26.24%), other industrial sources (15.19%), and traffic source (12.24%) were the major sources for ambient VOCs in Shijiazhuang. The spatial distributions of major industrial activities emissions were identified by using geographic information statistics system, which illustrated the VOCs was mainly from the north and southeast of Shijiazhuang. The inverse trajectory analysis using Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) and Potential Source Contribution Function (PSCF) clearly demonstrated the features of pollutant transport to Shijiazhuang. These findings can provide references for local governments regarding control strategies to reduce VOCs emissions.
Emissions of volatile organic compounds (VOCs) were studied during paper and cardboard recycling from a paper and cardboard solid waste recycling factory (PCSWRF). Data are summarized in this article for the following quantities for a PCSWRF during the winter in Tehran, Iran: VOC concentrations (μg m-3), the percentage of detected VOCs, exposure indices (Ei) of individual and total VOCs (TVOCs), inhalation lifetime cancer risk (LTCR) of VOCs, the hazard quotient (HQ) of VOCs, sensitivity analysis (SA) for VOC exposure in different age groups (birth to <81), and Spearman's rank correlation coefficients (r) between VOC concentrations and meteorological parameters. For more insight please see "Characteristics and Health Effects of Volatile Organic Compound Emissions during Paper and Cardboard Recycling"[1], https://doi.org/10.1016/j.scs.2019.102005.
Pure and Ti-doped NiO multiroom spheres were prepared via ultrasonic spray pyrolysis, and their gas sensing characteristics were investigated. The sensor using 10 at% Ti-doped NiO multiroom spheres exhibited an unprecedented high response (resistance ratio = 337.8) to 1 ppm p-xylene at 350 ℃, whereas the sensor using pure NiO multiroom spheres exhibited a negligibly low response (1.3). Moreover, the control of the Ti doping and film thickness provided intriguing strategies for tuning the xylene and methylbenzene sensing characteristics, such as the selectivity, response, sensitivity (slope between response and gas concentration), and detection limit. The versatile tunability on gas sensing characteristics was explained by the Ti-doping-induced variation of the oxygen adsorption, mesoporosity, specific surface area, and charge-carrier concentration, as well as the control over the reforming and oxidation of the analyte gases using the multiroom-structured micro-reactors with high catalytic activity.
Refined petroleum products are handled in gasoline storage and distribution facility to be conveyed to the end users. These are done through loading operations. During loading operations benzene vapor escape from various emissions sources and the level of benzene exposure concentration alter, based on several factors. However, the lack of monitoring data in some oil exporting developing countries, makes challenging the chemical exposure assessment in these facilities. Therefore, identifying, prioritizing and understanding the interactions of factors that influence benzene exposure concentration during loading operations at gasoline storage and distribution facility in developing country would help management to conduct a more comprehensive and accurate chemical risk assessment. The interpretive structural modeling methodology for identifying the direct and indirect relationships between the factors describe the situation far more accurately than an individual factor taken in isolation. Therefore, represents the suitable tool to conduct our research. The results of this study reveals that the identified factors such as: ‘’product’’, ‘’regulation’’, ‘’working practices’’ and ‘’installation’’ are the most influential for benzene exposure concentration level at gasoline storage and distribution facility in developing countries. Based on those results, management should tackle first these factors before others and emphasize on strategy to improve these factors with the view of providing a safe working place through a benzene exposure concentration level lower than the occupational exposure limit.
A single gas sensor with dual functionality for ultrasensitive and highly selective detection of p-xylene and toluene was designed using NiO hollow spheres doped with Nb. The pure and Nb-doped NiO hollow spheres were prepared by one-pot ultrasonic spray pyrolysis and subsequent heat treatment at 500 °C for 2 h. The Nb-doped NiO hollow spheres ([Nb]/[Ni] = 0.1) showed an ultrahigh response to 5 ppm of p-xylene (resistance ratio = 1752) and toluene (resistance ratio = 607), with negligible cross-responses to 5 ppm ethanol, benzene, carbon monoxide, and formaldehyde. In contrast, pure NiO hollow spheres showed negligibly low responses to 5 ppm of all analyte gases. In addition, the Nb-doped NiO hollow spheres exhibited dual sensing characteristics for selectively detecting p-xylene and toluene at 350 °C and 400 °C, respectively. The significant improvement of the response and selectivity for p-xylene and toluene can be explained by the high gas accessibility of hollow spheres, the Nb-doping-induced decrease in the charge carrier concentration, and the catalytic promotion of gas reforming reaction of less reactive xylene and toluene into more active species. The dual function of selectively detecting p-xylene and toluene in Nb-doped NiO hollow spheres is explained by the competition between oxidative filtering and gas reforming reaction depending on the operation temperature and sensing film thickness. The Nb-doped NiO hollow spheres can be used to design a single gas sensor with dual selectivity of xylene and toluene for reliable monitoring of the indoor air quality.
Mixed exposure to chemical products is a topical issue for occupational health and often includes exposure to volatile organic compounds (VOCs). As very few methods are available for evaluating these mixed exposures, the aim of this work was to develop a simple biomonitoring method to assess simultaneous occupational exposures to chlorinated and aromatic VOCs by analyzing the unmetabolized fraction of the VOCs in the urine of workers.
Volatile organic compounds were analyzed using dynamic headspace gas chromatography coupled to mass spectrometry (dHS-GC–MS), and 11 unmetabolized urinary VOCs were measured into headspace phase, without any time-consuming pretreatment. Simultaneously, a standardized collection protocol was designed to avoid VOC losses or the contamination of urinary samples. The calibration samples were real urines, spiked with known amounts of the VOC mixtures studied. Test investigations were performed on potentially exposed workers in three factories in order to assess the effectiveness of both the collection protocol and analytical method.
A satisfactory level of sensitivity was achieved, with limits of quantification (LOQ) between 10 and 15 ng/L obtained for all VOCs (except for styrene at 50 ng/L). Calibration curves were linear in the 0–20 μg/L range tested, with R² correlation coefficients of 0.991 to 0.998. At the lowest concentration tested (0.08 μg/L), within-day precision varied from 2.1 to 5.5% and between-day precision ranged from 2.7 to 8.5%.
Sample stability at −20 °C required that urinary samples be analyzed within 3 months. Even though the urinary concentrations of VOCs used in the plants were mostly quite low, significant differences between post-shift and pre-shift were observed.
In conclusion, a fast, sensitive, specific and easy-to-use method has been developed for extracting VOCs from human urine using dHS-GC–MS. The method described has proven to be reliable for assessing current occupational exposure to chlorinated and aromatic VOCs in France.
The present study aimed to find a correlation between the self-reported smoking status of the residents of Tehran, Iran, and the urine cotinine as a biomarker of exposure to tobacco smoke. The self-reported data was collected from 222 participants who were living in the urban area of Tehran. The urine samples of participants were collected for cotinine analysis. Urine cotinine was measured by an enzymatic immunoassay technique. Tobacco smoking was reported by 76 (34.23 %) participants as the self-reported data, and the number of males in this report was higher than of females (p < 0.001). By adding the number of the self-reported non-smokers with cotinine levels above the cutoff value of >100 ng/ml to self-reported smokers, the smoking prevalence increased from 34.23 % (95 % CI 28.01-40.88 %) to 36.48 % (95 % CI 30.14-43.19 %). Using the cutoff value, sensitivity and specificity of the self-reported smoking status were respectively 90.12 % (95 % CI 81.46-95.64 %) and 98 % (95 % CI 93.91-99.55 %). The levels of agreement between self-reported tobacco smoking and urinary cotinine concentrations was 95.1 % (k = 0.89, p < 0.001, 95 % CI = 0.81-0.95). Based on the results, self-reported smoking can be a valid marker for assessing the tobacco exposure, and it can be of use in large epidemiological studies.
Background and purpose: Biological monitoring for workers exposed to solvents includes complementary environmental monitoring which is useful in toxic chemical risk assessments. The aim of this study was environmental and biological monitoring of workers exposed to volatile organic compounds (VOCs) in petrochemical industry. Material and Methods: Air and urine samples were collected from 104 individuals working in petrochemical industry. NIOSH 2549 method was used to determine the concentrations of benzene, toluene, xylene isomers, phenol, and methyl ethyl ketone in breathing environment. In order to determine the concentration of urinary metabolites, urine samples were analyzed by high performance liquid chromatography and gas chromatography. Urinary creatinine level was measured by UV-VIS spectrophotometer. To analyze the data t-test and linear regression were performed in SPSS V.16. Results: The mean concentrations of benzene, toluene, O and m-xylene, P-xylene, phenol and methyl ethyl ketone in breath samples were 1.192, 1.300, 1.97, 1.290, 0.0116, and 2.243 ppm, respectively. The mean concentrations of urinary trans, t-MA, hippuric acid, 2, 3 and 4-methyl hippuric acid, and phenol were 1431 µgr/grCr, 0.3949, 0.4444, 0.1483 gr/grCr, and 0.5850mgr/grCr creatinine, respectively. Concentrations of urinary methyl ethyl ketone were 0.154 mgr/lit. There was a direct linear relationship between concentration of VOCs in the air and urinary metabolites (P<0.05). The results showed that increase in working hours per week resulted in increased level of urinary t, t-MA, methyl hippuric acid isomers and phenol (P<0.05). Conclusion: The mean concentration of benzene in breathing environment, urinary t, and t-MA was higher than the ACGIH's Threshold Limit Values (TLV) and Biological Exposure Indices (BEI) while the mean concentrations of other compounds were lower than TLV and BEI. We also found that smoking increased urinary excretion of all metabolites expect hippuric acid.
The health risk resulting from benzene exposure in petroleum refineries was calculated using data from the scientific literature from various countries throughout the world. The exposure data was collated into four scenarios from petroleum refinery environments and plotted as cumulative probability distributions (CPD) plots. Health risk was evaluated for each scenario using the Hazard Quotient (HQ) at 50% (CEXP50) and 95% (CEXP95) exposure levels. Benzene levels were estimated to pose a significant risk with HQ50 > 1 and HQ95 > 1 for workers exposed to benzene as base estimates for petroleum refinery workers (Scenario 1), petroleum refinery workers evaluated with personal samplers in Bulgarian refineries (Scenario 2B) and evaluated using air inside petroleum refineries in Bulgarian refineries (Scenario 3B). HQ50 < 1 were calculated for petroleum refinery workers with personal samplers in Italian refineries (Scenario 2A), air inside petroleum refineries (Scenario 3A) and air outside petroleum refineries (Scenario 4) in India and Taiwan indicating little possible adverse health effects. Also, HQ95 was < 1 for Scenario 4 however potential risk was evaluated for Scenarios 2A and 3A with HQ95 > 1. The excess Cancer risk (CR) for lifetime exposure to benzene for all the scenarios was evaluated using the Slope Factor and Overall Risk Probability (ORP) methods. The result suggests a potential cancer risk for exposure to benzene in all the scenarios. However, there is a higher cancer risk at 95% (CEXP95) for petroleum refinery workers (2B) with a CR of 48,000 per 106 and exposure to benzene in air inside petroleum refineries (3B) with a CR of 28,000 per 106.
Quantitative information regarding the endmember composition of the gas and oil that flowed from the Macondo well during the Deepwater Horizon oil spill is essential for determining the oil flow rate, total oil volume released, and trajectories and fates of hydrocarbon components in the marine environment. Using isobaric gas-tight samplers, we collected discrete samples directly above the Macondo well on June 21, 2010, and analyzed the gas and oil. We found that the fluids flowing from the Macondo well had a gas-to-oil ratio of 1,600 standard cubic feet per petroleum barrel. Based on the measured endmember gas-to-oil ratio and the Federally estimated net liquid oil release of 4.1 million barrels, the total amount of C(1)-C(5) hydrocarbons released to the water column was 1.7 10(11) g. The endmember gas and oil compositions then enabled us to study the fractionation of petroleum hydrocarbons in discrete water samples collected in June 2010 within a southwest trending hydrocarbon-enriched plume of neutrally buoyant water at a water depth of 1,100 m. The most abundant petroleum hydrocarbons larger than C(1)-C(5) were benzene, toluene, ethylbenzene, and total xylenes at concentrations up to 78 μg L(-1). Comparison of the endmember gas and oil composition with the composition of water column samples showed that the plume was preferentially enriched with water-soluble components, indicating that aqueous dissolution played a major role in plume formation, whereas the fates of relatively insoluble petroleum components were initially controlled by other processes.
Benzene is a ubiquitous pollutant; smoking habit, genetic polymorphisms, and analytical difficulties impact the identification of the best biomarker.
To apply a systematic quantitative approach to evaluate urinary benzene (BEN-U) and S-phenylmercapturic acid (SPMA) as biomarkers of low benzene exposures.
Seventy-one blue collar refinery workers, 97 white collar refinery workers and 108 general population subjects were included. Intrinsic characteristics, sampling and analytical issues were compared.
BEN-U and SPMA were detected in 99% and 78% of samples, which correlated with benzene exposure (r = 0.456 and r = 0.636, respectively) and with urinary cotinine (r = 0.630 and r = 0.570, respectively). Intrinsic characteristics were similar for the two biomarkers: specificity (0.64 and 0.69 for BEN-U and SPMA), sensitivity (0.74 and 0.83), as well as intra- and inter-individual variability (150% and >14 for both).
BEN-U and SPMA show similar intrinsic characteristics; analytical issues in detecting SPMA suggest that BEN-U is more convenient for investigating low exposure levels.
Benzene is a human carcinogen and an ubiquitous environmental pollutant. Identification of specific and sensitive biological markers is critical for the definition of exposure to low benzene level and the evaluation of the health risk posed by this exposure. This investigation compared urinary trans,trans-muconic acid (t,t-MA), S-phenylmercapturic acid, and benzene (U-benzene) as biomarkers to assess benzene exposure and evaluated the influence of smoking and the genetic polymorphisms CYP2E1 (RsaI and DraI) and NADPH quinone oxidoreductase-1 on these indices. Gas station attendants, urban policemen, bus drivers, and two groups of controls were studied (415 subjects). Median benzene exposure was 61, 22, 21, 9 and 6 microg/m(3), respectively, with higher levels in workers than in controls. U-benzene, but not t,t-MA and S-phenylmercapturic acid, showed an exposure-related increase. All the biomarkers were strongly influenced by cigarette smoking, with values up to 8-fold higher in smokers compared with nonsmokers. Significant correlations of the biomarkers with each other and with urinary cotinine were found. A possible influence of genetic polymorphism of CYP2E1 (RsaI and/or DraI) on t,t-MA and U-benzene in subjects with a variant allele was found. Multiple linear regression analysis correlated the urinary markers with exposure, smoking status, and CYP2E1 (RsaI; R(2) up to 0.55 for U-benzene). In conclusion, in the range of investigated benzene levels (<478 micro/m(3) or <0.15 ppm), smoking may be regarded as the major source of benzene intake; among the study indices, U-benzene is the marker of choice for biomonitoring low-level occupational and environmental benzene exposure.
The relationships between levels of volatile organic compounds (VOCs) in blood and air have not been well characterized in the general population where exposure concentrations are generally at parts per billion levels. This study investigates relationships between the levels of nine VOCs, namely, benzene, chloroform, 1,4-dichlorobenzene, ethylbenzene, methyl tert-butyl ether (MTBE), tetrachloroethene, toluene, and m-/p- and o-xylene, in blood and air from a stratified random sample of the general US population. We used data collected from 354 participants, including 89 smokers and 265 nonsmokers, aged 20-59 years, who provided samples of blood and air in the National Health and Nutrition Examination Survey (NHANES) 1999-2000. Demographic and physiological characteristics were obtained from self-reported information; smoking status was determined from levels of serum cotinine. Multiple linear regression models were used to investigate the relationships between VOC levels in air and blood, while adjusting for effects of smoking and demographic factors. Although levels of VOCs in blood were positively correlated with the corresponding air levels, the strength of association (R(2)) varied from 0.02 (ethylbenzene) to 0.68 (1,4-DCB). Also the blood-air relationships of benzene, toluene, ethylbenzene, and the xylenes (BTEX) were influenced by smoking, exposure-smoking interactions, and by gender, age, and BMI, whereas those of the other VOCs were not. Interestingly, the particular exposure-smoking interaction for benzene was different from those for toluene, ethylbenzene, and the xylenes. Whereas smokers retained more benzene in their blood at increasing exposure levels, they retained less toluene, ethylbenzene, and xylenes at increasing exposure levels. Investigators should consider interaction effects of exposure levels and smoking when exploring the blood-air relationships of the BTEX compounds in the general population.
The aim of this study was to evaluate benzene, toluene, ethylbenzene, and xylene (BTEX) exposure among workers at four stations of a major oil distribution company. Personal BTEX exposure samples were collected over working shift (8 h) for 50 workers at four stations of a major oil distribution company in Iran. Measured mean values for workers across four sites were benzene (2437, 992, 584, and 2788 μg/m³ respectively), toluene (4415, 2830, 1289, and 9407 μg/m³), ethylbenzene (781, 522, 187, and 533 μg/m³), and xylene (1134, 678, 322, and 525 μg/m³). The maximum mean concentration measured across sites for benzene was 2788 μg/m³ (Station 4), toluene was 9407 μg/m³ (Station 4), ethylbenzene was 781 μg/m³ (Station 1) and xylene was 1134 μg/m³ (Station 1). The 8 h averaged personal exposure benzene concentration exceeded the recommended value of 1600 μg/m³ established by the Iranian Committee for Review and Collection of Occupational Exposure Limit and American Conference of Governmental Industrial Hygienists. Mean values for excess lifetime cancer risk for exposure to benzene were then calculated across workers at each site. Estimates of excess risk ranged from 1.74 ± 4.05 (Station 4) to 8.31 ± 25.81 (Station 3). Risk was assessed by calculation of hazard quotients and hazard indexes, which indicated that xylene and particularly benzene were the strongest contributors. Tanker loading was the highest risk occupation at these facilties. Risk management approaches to reducing exposures to BTEX compounds, especially benzene, will be important to the health of workers in Iran.
Individuals working with benzene, and especially those exposed to it over a long period of time, are at risk for developing benzene-related illnesses, which range from anemia to leukemia. The current study evaluates the health risks of exposure to benzene vapor in gas station refueling workers. A real-time monitor was used to measure workers' exposure to benzene and evaluate the risk level. The mean personal exposure of 18 refueling workers in 3 gas stations in Juybar (Iran) was 1.35±1.15 ppm, indicative of a significant health risk. The refueling workers in gas stations in Juybar city center experienced the highest benzene vapor exposures and their health risk level was considered very high. From all metereological parameters measured, only wind speed during the monitoring was a predictor of workers' exposure to benzene vapor as it contributed to dilute benzene vapor in the workers'breathing zone.
Objective:
To assess exposure to benzene (BEN) and other aromatic compounds (toluene, ethylbenzene, m+p-xylene, o-xylene) (BTEX), methyl tert-butyl ether (MTBE), and ethyl tert-butyl ether (ETBE) in petrol station workers using air sampling and biological monitoring and to propose biological equivalents to occupational limit values.
Methods:
Eighty-nine petrol station workers and 90 control subjects were investigated. Personal exposure to airborne BTEX and ethers was assessed during a mid-week shift; urine samples were collected at the beginning of the work week, prior to and at the end of air sampling.
Results:
Petrol station workers had median airborne exposures to benzene and MTBE of 59 and 408 µg m(-3), respectively, with urinary benzene (BEN-U) and MTBE (MTBE-U) of 339 and 780ng l(-1), respectively. Concentrations in petrol station workers were higher than in control subjects. There were significant positive correlations between airborne exposure and the corresponding biological marker, with Pearson's correlation coefficient (r) values of 0.437 and 0.865 for benzene and MTBE, respectively. There was also a strong correlation between airborne benzene and urinary MTBE (r = 0.835). Multiple linear regression analysis showed that the urinary levels of benzene were influenced by personal airborne exposure, urinary creatinine, and tobacco smoking [determination coefficient (R (2)) 0.572], while MTBE-U was influenced only by personal exposure (R (2) = 0.741).
Conclusions:
BEN-U and MTBE-U are sensitive and specific biomarkers of low occupational exposures. We propose using BEN-U as biomarker of exposure to benzene in nonsmokers and suggest 1457ng l(-1) in end shift urine samples as biological exposure equivalent to the EU occupational limit value of 1 p.p.m.; for both smokers and nonsmokers, MTBE-U may be proposed as a surrogate biomarker of benzene exposure, with a biological exposure equivalent of 22 µg l(-1) in end shift samples. For MTBE exposure, we suggest the use of MTBE-U with a biological exposure equivalent of 22 µg l(-1) corresponding to the occupational limit value of 50 p.p.m.
Detection of Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) compound using electrochemical mixed potential gas sensor has been reported. In this study, three sensors of different configuration were used to detect BTEX. The sensitivity and selectivity of three sensor configurations to BTEX were compared. The sensor configuration with Strontium doped Lanthanum Chromite (La0.8Sr0.2CrO3, abbreviated as LSCO) electrode and Pt electrode with Yttria-Stabilized Zirconia electrolyte exhibited maximum sensitivity and selectivity to BTEX. The detection limit using the mixed potential tape cast sensor was found to be 0.5 ppm. For all the sensors, the mixed potential was found to vary linearly with BTEX concentration. The use of a cold-wall set-up and heterogeneous catalysis studies are envisioned to lower the BTEX detection limits to ppb levels without compromising sensitivity.
Concerns have been raised about whether the Deepwater Horizon oil spill cleanup workers experienced adverse health effects from exposure to airborne benzene, toluene, ethylbenzene, and xylene (BTEX) which volatilized from surfaced oil. Thus, we analyzed the nearly 20 000 BTEX measurements of breathing zone air samples of offshore cleanup workers taken during the six months following the incident (made publicly available by British Petroleum). The measurements indicate that 99% of the measurements taken prior to capping the well were 32-, 510-, 360-, and 77-fold lower than the U.S. Occupational Safety and Health Administration's Permissible Exposure Limits (PELs) for BTEX, respectively. BTEX measurements did not decrease appreciably during the three months after the well was capped. Moreover, the magnitudes of these data were similar to measurements from ships not involved in oil slick remediation, suggesting that the BTEX measurements were primarily due to engine exhaust rather than the oil slick. To supplement the data analysis, two modeling approaches were employed to estimate airborne BTEX concentrations under a variety of conditions (e.g., oil slick thickness, wind velocity). The modeling results corroborated that BTEX concentrations from the oil were well below PELs and that the oil was not the primary contributor to the measured BTEX.
A comparative evaluation of urinary biomarkers was carried out to characterize benzene exposure in a group of 100 traffic policemen of the city of Parma (Italy). All subjects were monitored once, in two consecutive days characterized by similar climatic conditions but preceded by two windy days. Benzene ambient concentration measured by municipal air monitoring stations was 1 microg/m(3) (Day 1) and 2 microg/m3 (Day 2). Personal exposure to ambient concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) was assessed by using Radiello((R)) passive-diffusive samplers in a subgroup of 24 workers. Benzene metabolites, t,t-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA) were determined by isotopic dilution liquid chromatography-tandem mass spectrometry on spot urine samples collected at the end of the shift. Urinary benzene (U-B) was determined by solid-phase microextraction gas chromatography-mass spectrometry. Airborne benzene concentration expressed as median [and interquartile range] was 6.07 [0.28-9.53] microg/m(3), as assessed by personal sampling. Urinary concentrations of biomarkers in the whole group were 41.8 [34.1-89.8] microg/g creatinine for t,t-MA, 0.67 [0.23-1.32] microg/g creatinine for S-PMA, and 0.16 [0.13-0.26] microg/l for U-B. Smokers eliminated significantly higher concentrations of unchanged BTEX and benzene metabolites than non-smokers (p < 0.05). When traffic policemen were distinguished into indoor (n=31) and outdoor workers, no significant differences were observed for either airborne benzene or urinary biomarkers. Significantly lower concentrations of S-PMA and U-B were determined in samples collected at Day 1 as compared to Day 2 (p < 0.0001 and p = 0.003, respectively) suggesting that these biomarkers are enough sensitive and specific to detect changes in airborne benzene concentration even at few microg/m(3).
The present work was aimed to study in petrochemical industry operators the correlation, if any, between environmental exposure to low levels of benzene and two biological exposure indexes in end-shift urine, i.e. trans, trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (SPMA). Exposure to benzene was assessed in 133 male subjects employed in outdoor operations in a petrochemical plant, using personal passive-diffusive air samplers worn at the breathing zone; adsorbed benzene was determined by GC-FID analysis. S-PMA was determined by a new HPLCMS/MS method, after (quantitative) acidic hydrolysis of the cysteine conjugate precursor. t,t-MA was measured by an HPLC-UV method. Smoking habits were assessed by means of a self-administered questionnaire.
The rate of the Jaffé reaction depends on the concentration of sodium hydroxide; the pseudo-first-order rate constant of the reaction, at 37 degrees C in 10 mmol/L picrate solution, is 0.004 mmol/L. We formulated an automated method to determine urinary creatinine directly without manual sample dilution. The conditions are as follows: 10 mmol/L picrate and 60 mmol/L sodium hydroxide (final concentrations); ratio of sample to final volume, 1:41; temperature, 37 degrees C; wavelengths of measurement, 500 or 510 nm; interval of measurement, 30 to 90 s; and mode of measurement, kinetic. Determinations of creatinine in patients' samples by the new method compared favorably with those obtained with the AutoAnalyzer and aca. The run-to-run CVs were 3.6% or less, and the method was accurate for concentrations of creatinine up to 3000 mg/L. We recommend this method as a good replacement for the AutoAnalyzer or aca methods.
Phenol is not reliable as a biomarker for exposure to benzene at concentrations below 5 ppm (8-hr time-weighted average [TWA]). S-Phenylmercapturic acid (S-PMA) and trans-trans-muconic acid (tt-MA), two minor urinary metabolites of benzene, have been proposed as biomarkers for low-level exposures. The aim of this study was to compare their suitability as biomarkers. S-PMA and tt-MA were determined in 434 urine samples collected from 188 workers in various settings in the petrochemical industry and from 52 control workers with no occupational exposure to benzene. Benzene concentrations in the breathing zone of the potentially exposed workers were assessed by personal air monitoring. Strong correlations were found between S-PMA and tt-MA concentrations in end-of-shift samples and between either of these parameters and airborne benzene concentrations. Exposure to 1 ppm benzene (8-hr TWA) leads to an average concentration in end-of-shift samples of 21 mol S-PMA and 1.5 mmol tt-MA per mol creatinine. Of an inhaled dose of benzene, on average 0.11% (range 0.05-0.26%) was excreted as S-PMA with an apparent elimination half-life of 9.1 (standard error [SE] 0.7) hr and 3.9% (range 1.9-7.3%) as tt-MA with a half-life of 5.0 (SE 0.5) hr. Due to its longer elimination half-life, S-PMA proved a more reliable biomarker than tt-MA for benzene exposures during 12-hr shifts. Specificity of S-PMA, but not tt-MA, was sufficient to discriminate between the 14 moderate smokers and the 38 nonsmokers from the control group. The mean urinary S-PMA was 1.71 (SE 0.27) in smokers and 0.94 (SE 0.15) mol/mol creatinine in nonsmokers (p = 0.013). The mean urinary tt-MA was 0.046 (SE 0.010) in smokers and 0.029 (SE 0.013) mmol/mol creatinine in nonsmokers (p = 0.436). The inferior specificity of tt-MA was due to relatively high background values of up to 0.56 mmol/mol creatinine, which may be found in nonexposed individuals and limits the use of tt-MA to concentrations of benzene over 1 ppm (8-hr TWA). We conclude that S-PMA is superior to tt-MA as a biomarker for low-level benzene exposures because it is more specific, enabling reliable determination of benzene exposures down to 0.3 ppm (8-hr TWA), and because its longer half-life makes it more suited for biological monitoring of operators working in shifts longer than 8 hr.
An exposure risk assessment of workers in a refinery production unit was undertaken. Gasoline and its main components were investigated through environmental and biological monitoring. Measured variables were environmental benzene, toluene, pentane and hexane; benzene and toluene in blood and urine; tt-MA (metabolite of benzene) in urine. Multivariate statistical analysis of the data showed that worker's exposure to the above substances fell within the limits specified by organisations such as ACGIH. Also, biological values complied with reference values (RV) for non-occupationally-exposed population. Different values of biological variables were determined by separating smokers from non-smokers: smokers had hematic and urinary benzene values significantly higher than non-smokers. During a 3-yr sampling, it was possible to identify a significant decrease of benzene in the workplace air and of hematic benzene for non-smokers. The most exposed department, one in which tank-lorries were loaded, needs further investigation and extended monitoring.
This study evaluated the relationship between the breath concentrations of, and personal exposure to, toluene, xylene and ethylbenzene of thirty workers from ten gasoline stations. Personal exposure air samples and workplace samples were collected simultaneously. Each subject provided a sample of exhaled breath after his or her personal exposure air was sampled. Twenty-five personal air, 17 workplace and 30 breath samples were collected in this study. Results indicated that breath concentrations of toluene and xylene were significantly correlated with personal monitoring concentrations. Furthermore, multiple regression analysis showed that exhaled toluene levels were highly influenced by personal toluene concentrations and the amount of personal gasoline sold (r2 = 0.762), while exhaled xylene levels depended on wind speed and personal xylene exposure concentrations (r2 = 0.665). Exhaled ethylbenzene levels were too low to present a relationship between concentrations and personal exposure levels. The exhaled toluene, xylene and ethylbenzene concentrations ranged from 4.3 to 41.8, 0.9 to 13.9, and 0.2 to 6.5 ppb, and the corresponding personal monitoring concentrations ranged from 60.3 to 572.3, 16.4 to 156.6, and 10.7 to 136.6, respectively. The average number of symptoms per person, according to neurotoxic questionnaire 16 (abbreviated as Q16) was 4.1 and six workers showed over six symptoms in Q16. This study suggests that exhaled toluene and xylene levels are suitable for use as biological exposure indices even at the ppb-level of exposure. Gasoline service workers are exposed to high levels of volatile organic compounds (VOCs) and the potential threats to their neurological systems deserve further investigation.
We initiated the PETER (pedestrian environmental traffic pollutant exposure research) project to investigate pedestrians' exposure to traffic related atmospheric pollutants, based on data obtained with the collaboration of selected categories of pedestrian urban workers. We investigated relations between roadside personal exposure levels of volatile aromatic hydrocarbons (including benzene) and particulate matter <10 microm (PM10) among traffic police (n = 126) and parking wardens (n = 50) working in downtown Bologna, Italy. Data were collected from workshifts throughout four 1-week periods in different seasons of 2000-2001. For benzene and PM10, comparisons were made with measurements by fixed monitoring stations, and influence of localized traffic intensity and meteorological parameters was examined. Roadside personal exposure to benzene correlated more strongly with other volatile aromatic hydrocarbons (toluene, xylenes and ethylbenzene) than with PM10. Benzene and PM10 personal exposure levels were higher than fixed monitoring station values (both p<0.0001). At multivariate analysis, benzene and PM10 data from fixed monitoring stations both correlated with meteorological variables, and were also influenced by localized traffic intensity. Plausibly because of the downtown canyon-like streets, weather conditions (during a period of drought) only marginally affected benzene personal exposure, and moderately affected PM10 personal exposure. These findings reinforce the concept that urban atmospheric pollution data from fixed air monitoring stations cannot automatically be taken as indications of roadside exposures.
Regression models were modified by age and cotinine. c Regression models were modified by age and job role. d Regression models were modified by age, cotinine, job role and creatinine. e Regression models were modified by age, cotinine and creatinine
Note:
a Regression models were modified by age, cotinine and job role.
b Regression models were modified by age and cotinine.
c Regression models were modified by age and job role.
d Regression models were modified by age, cotinine, job role and creatinine.
e Regression models were modified by age, cotinine and creatinine.
References
ACGIH, 2011. Threshold Limit Values for Chemical Substances and Physical Agents and
Biological Exposure Indices. American Conference of Governmental Industrial,
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WHO, Working Group, 1996. Updating and Revision of the Air Quality Guidelines for
Europe; Report on the WHO Working Group on Volatile Organic Compounds. EUR/
ICP/EHAZ 94 05/MT12.
Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. American Conference of Governmental Industrial
ACGIH, 2011. Threshold Limit Values for Chemical Substances and Physical Agents and
Biological Exposure Indices. American Conference of Governmental Industrial,
Cincinnati.