Xylene Exposure Research Articles

Deep eutectic solvent functionalized graphene oxide composite adsorbent for miniaturized pipette-tip solid-phase extraction of toluene and xylene exposure biomarkers in urine prior to their determination with HPLC-UV.

A deep eutectic solvent functionalized graphene oxide composite adsorbent (DFG) was synthesized through reversible-addition fragmentation chain-transfer polymerization. The synthesized DFG had multiple adsorption interactions after covalent modification with a deep eutectic solvent (allyltriethylammonium bromide/ethylene glycol). Adsorption isotherms and kinetics studies of DFG indicate that the adsorption of hippuric acid (HA) and methylhippuric acid (MHA) was monolayer chemical adsorption. The comparison of DFG with commercial adsorbents demonstrates that the adsorption ability of DFG was superior. This was due to the multiple adsorption interactions of DFG for the three analytes (mainly π-interaction, hydrogen bonding, electrostatic adsorption, and hydrophobic interaction). The DFG adsorbent was applied to miniaturized pipette-tip solid-phase extraction (MPT-SPE), followed by high-performance liquid chromatography (HPLC) to determine biomarkers in urine for toluene and xylene exposure. The DFG-MPT-SPE-HPLC method required only 2.00mg of DFG as adsorbent, 0.50mL of washing solvent, and 0.40mL of elution solvent to achieve a wide linear range (0.200-200μgmL-1), high recoveries (90.9-99.1%), and high precision (RSD ≤ 6.3%). The proposed method was applied to determine HA and MHA in urine samples from occupational workers. Graphical abstract Deep eutectic solvent functionalized graphene oxide composite adsorbent for miniaturized pipette-tip solid-phase extraction of toluene and xylene exposure biomarkers in urine prior to their determination with HPLC-UV.

Personal exposure to NO2 and benzene in the Cape Town region of South Africa is associated with shorter leukocyte telomere length in women

Air pollution exposure is a major global health concern and has been associated with molecular aging. Unfortunately, the situation has not received much attention in the African region. The aim of this study was to investigate whether current personal ambient NO2 and benzene, toluene, ethyl-benzene and xylenes (ortho (o)-, meta (m)- and para (p)-xylene (BTEX) exposure is associated with leukocyte telomere length (LTL), a marker of molecular ageing, in apparently healthy women (mean ± SD age: 42.5 ± 13.4 years) residing in the Cape Town region of South Africa. The repeated measures study collected data from 61 women. Seven-day median (interquartile range (IQR)) personal NO2 and BTEX exposure levels were determined via compact passive diffusion samplers carried on the person prior to baseline (NO2: 14.2 (9.4–17.2) μg/m³; Benzene: 3.1 (2.1–5.3) μg/m³) and 6-month follow-up (NO2: 10.6 (6.6–13.6) μg/m³; Benzene: 2.2 (1.3–4.9) μg/m³) visits. LTL was measured at baseline and follow-up using a real-time PCR method. Multiple linear mixed model analyses (adjusting for age, body mass index, smoking, employment status, level of education and assessment visit) showed that each IQR increment increase in NO2 (7.0 μg/m³) and benzene (3.3 μg/m³) was associated with −7.30% (95% CI: −10.98 to −3.46%; p < 0.001) and −6.78% (95% CI: −11.88 to −1.39%; p = 0.015) difference in LTL, respectively. The magnitude of these effects of NO2 and benzene corresponds to the effect of an increase of 10.3- and 6.0-year in chronological age on LTL. Our study shows that personal exposures to NO2 and benzene are associated with molecular ageing as indicated by LTL in healthy women residing in the Cape Town region.

Occupational Exposure to Petroleum Workers by Assessing Urinary Methyl Hippuric Acid and Micronuclei in Oral Mucosa Cell

Xylene is an important component of petrol and 98% of Xylene is derived from the petroleum refining industries. When human get expose to xylene, which is one of the major genotoxicant, which may induce with a range of acute/chronic diseases but occurrence of cancer is still not available in literature. Taking into our mind that our study aims to investigate and correlate the micronuclei in exfoliated oral epithelial cells with urinary methylhippuric acid level estimation among petrol pump workers. Aims & Objectives: • To evaluate occupational exposure of xylene in petrol pump workers by assessing urinary methylhippuric acid level. • To determine the correlation between the level of urinary methylhippuric acid and the micronuclei of exfoliated epithelial cells of buccal mucosa. Materials and Method: Urine samples and oral buccal mucosa smears were collected from 30 healthy individual (control) and 30 petroleum pump workers (case) working in petroleum station. The urinary methylhippuric acid (MHA) level was analysed by using Shimadzu UV-Visible Spectrophotometer procedure. The smeared slides were stained with PAP stain and analyse the micronuclei of exfoliated epithelial cells by using Axio Vision SE64 Rel 4.9.1. Ink Software. Results: The urinary Methylhippuric acid level was substantially higher in cases than in controls (p<0.001). The Micronuclei (MN) frequency was drastically increased in cases than in controls and was statistically highly significant (P<0.0001). The frequency of MN gradually increased along with increased urinary MHA level in petroleum pump workers. Conclusion: The urinary MHA level and MN frequency is a useful index to recognize the occupational exposure to the petroleum product. Thus, our study emphasizes that appropriate precaution and regular biomonitoring must be taken among petrol pump workers which shall help to reduce their potential levels of risk associated with the occupation.

Environmental and biological monitoring of benzene, toluene, ethylbenzene and xylene (BTEX) exposure in residents living near gas stations

ABSTRACTThe volatile organic compounds benzene, toluene, ethylbenzene, and xylene (BTEX) are emitted into the atmosphere at gas stations (GS) leading to chronic exposure of nearby residents, which raises public health concerns. This study aimes at determining the contribution of GS emissions to BTEX exposure in nearby residents. Three Control and Exposed areas to BTEX emissions from GS were defined in a medium-sized European city (Porto, Portugal). BTEX atmospheric levels were determined in Control and Exposed areas using passive samplers deployed outdoors (n = 48) and indoors (n = 36), and human exposure was estimated for 119 non-smoking residents using the first urine of the day. Results showed that median BTEX outdoor and indoor concentrations were significantly higher for Exposed than Control areas, with exception of ethylbenzene and xylene indoor concentrations, where no marked differences were found. Comparison of urinary concentrations between Exposed and Control residents demonstrated no significant differences for benzene and ethylbenzene, whereas levels of toluene and xylene were significantly higher in Exposed residents. No marked correlation was obtained between atmospheric BTEX concentrations and urinary concentrations. Data indicate the potential impact on air quality of BTEX emissions from GS, which confirms the importance of these findings in urban planning in order to minimize the impact on health and well-being of surrounding populations.

Occupational exposure of benzene, toluene, ethylbenzene and xylene (BTEX) to pump attendants in Ghana: Implications for policy guidance

Gasoline plays an important role as fuel for engines, but its use is replete with a high probability of adverse health to persons along the distribution chain, especially pump attendants. This stud...

Toxicity of xylene in occupationally exposed workers: A high-performance liquid chromatography analysis.

Background:Xylene is one of the most commonly used solvents in industrial and medical technologies. Several health hazards of xylene have been documented in literature. Workers in certain forces appear to have the greatest potential for exposure to high concentrations of xylene – histopathology technicians and painters are two such groups. This study was undertaken with the aim to determine the level of xylene exposure and the various systemic health effects among these groups.Methodology:The study was performed by analyzing the urine samples of the participants for methylhippuric acid, the established biomarker of xylene with the aid of high-performance liquid chromatography.Results and Conclusion:The work hours per week of the occupationally exposed participants were statistically analyzed with that of the excretory values of the metabolites of xylene, and the P value was found to be highly significant. Various side effects of xylene including respiratory, dermatological, neurological and gastrointestinal symptoms were observed among the study groups.

An amino-functionalized mesoporous silica (KIT-6) as a sorbent for dispersive and ultrasonication-assisted micro solid phase extraction of hippuric acid and methylhippuric acid, two biomarkers for toluene and xylene exposure.

The authors described a new application of amino-functionalized KIT-6 for dispersive ultrasonication-assisted micro solid phase extraction of hippuric acid (HA) and methyl hippuric acid (MHA) from human urine and water samples. In the first step, an amino-functionalized mesoporous silica of type KIT-6 was synthesized. It was characterized by field emission scanning electron microscopy, Fourier transform infrared spectrometry, nitrogen adsorption-desorption analysis, thermogravimetry and X-ray diffraction. Following sorption and desorption with 1.0mL methanol/NH4OH (1%; v/v), HA and MHA were quantified by HPLC with UV detection. Various important parameters were optimized by Box-Behnken design. Under optimized conditions, The limit of detections (LOD) were calculated by a signal-to-noise ratio of 3, which were 0.5μgL-1 and 0.2μgL-1 for HA and MHA, respectively, and the calibration plot is linear in the 1-1000μgL-1 concentration range. Only small matrix effects were found. The method was successfully implemented for the sensitive determination of HA and MHA in (spiked) human urine samples. Graphical abstract Schematic of a sorbent for dispersive micro solid phase extraction coupled with ultrasonic power. It consists ofamino functionalized KIT-6 and was used for the simultaneous preconcentration and determination of low levels of hippuric and methyl hippuric acid in urine and water samples.

Pooled study of occupational exposure to aromatic hydrocarbon solvents and risk of multiple myeloma

ObjectivesTo investigate the association between occupational exposure to aromatic hydrocarbon solvents and risk of multiple myeloma (MM) in a large, consortium-based study.MethodsWe pooled data on 2854 cases and 10 743...

Exposure of xylene in working environment and methylhippuric acid in informal footwear worker in bogor, Indonesia

Exposure of xylene in working environment and methylhippuric acid in informal footwear worker in bogor, Indonesia

Chemical-Induced Hearing Loss in Shipyard Workers

The aim of this study was to determine the effect of lead, cadmium, arsenic, toluene, and xylene exposure on hearing compared with noise exposures alone. Personnel at a shipyard (n = 1266) were divided into four exposure groups on the basis of concentrations: low metals/low solvents/high noise (reference group), high metals/high solvents/low noise, high metals/low solvents/high noise, and high metals/high solvents/high noise. Hearing changes occurring from the years 2004 to 2015 were analyzed. Hearing changes were significantly worse at 1000 Hz (P = 0.007), averaged across 2000 to 4000 Hz (P = 0.014), and averaged across 500 to 6000 Hz (P = 0.014) for the high metals/high solvent/high noise group compared with the low metals/low solvents/high noise only reference group. Simultaneous exposures classified as high for metals/solvents/noise appear to damage hearing more than exposure to noise alone. Hearing conservation programs should take into consideration combined exposures to metals, solvents, and noise, not simply exposure to noise.

BTEX exposure assessment and quantitative risk assessment among petroleum product distributors

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 (8h) 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 2788μg/m3 respectively), toluene (4415, 2830, 1289, and 9407μg/m3), ethylbenzene (781, 522, 187, and 533μg/m3), and xylene (1134, 678, 322, and 525μg/m3). The maximum mean concentration measured across sites for benzene was 2788μg/m3 (Station 4), toluene was 9407μg/m3 (Station 4), ethylbenzene was 781μg/m3 (Station 1) and xylene was 1134μg/m3 (Station 1). The 8h averaged personal exposure benzene concentration exceeded the recommended value of 1600μg/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.

Expression of exosomal and cellular microRNAs: as biomarkers for toluene, ethylbenzene, xylene (TEX) exposure

Exosomes, small vesicles released by many cells, are associated with various biological processes and they can potentially be used for prognosis and therapy and as biomarkers of health. Thus, they are gaining attention in toxicological and pathological research. miRNA is also considered as a useful tool to predict health risk caused by environmental toxicants. Volatile organic compounds (VOCs), including toluene (T), xylene (X), and ethylbenzene (E), have been reported to be harmful. Although VOCs are prevalent in the environment, the mechanisms underlying their toxicity are not understood. In this study, a microarray analysis identified 50 miRNAs that were differentially expressed in exosomes and cytosols of HL-60 cell line exposed to three VOCs (TEX). A total of 3,355 putative target genes were classified according to the miRWalk 2.0 database. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the putative target genes showed a correlation with biological processes involved in the regulation of myeloid leukocyte differentiation, MAPK signaling pathway, and pathways in cancer. In conclusion, this study describes alterations in miRNA expression profiles in response to exposure to VOCs and related toxicity affected by significantly expressed target genes. Moreover, it illustrates the value of exosomes as diagnostic biomarkers of toxicity.

Análise simultânea dos indicadores biológicos de exposição aos solventes etilbenzeno, estireno, tolueno e xileno na urina por CLAE-UV

AND XYLENE SOLVENTS IN URINE BY HPLC-UV. A method for simultaneous analysis of phenylglyoxylic (PGA), mandelic (MA), hippuric (HA), orto-, meta- and para-methylhippuric (o-, m- and p-MHA) acids in urine, by high performance liquid chromatography with UV detection was developed and validated. The substances are biotransformation products used as biological indicators to assess the exposure of workers, respectively, to ethylbenzene, styrene, toluene and xylene. The urinary metabolites were separated using a C18 column and a mixture of 5 mM phosphate buffer pH 2.6:acetonitrile (92:8, v/v) as mobile phase. Urine samples were extracted with dichloromethane:ethyl acetate (70:30, v/v). The method used phenacetin as internal standard and was linear in the interval of 100-500 µg mL-1 for PGA and MA and 150-700 µg mL-1 for HA and MHA. The detection limits in µg mL-1, were 19.8 for PGA, 1.7 for MA, 4.1 for HA, 3.9 for o-MHA, 3.3 for m-MHA and 7.3 for p-MHA. Intra- and inter-assay precisions (as relative standard deviation) were all less than 15% and accuracy (as relative standard error) did not exceed 12.3%. The recovery was higher than 65% for all metabolites. The developed method will be applied to biological evaluation of workers exposure to these solvents.

PATHOLOGICAL LESIONS IN DIFFERENT ORGANS AFTER CHRONIC XYLENE AND UVB EXPOSURE IN MICE

The present study was designed to investigate the pathological lesions in different organs induced by chronic Ultraviolet type B (UVB) and Xylene exposure in mice. Forty mice were used in this study and divided into four groups; Group A (Control group, n=10) not exposed to UVB and Xylene, Group B (n=10) exposed to Xylene through painting the mouse’s back skin, Group C (n=10) which were exposed to UVB light only, while the remainder group (Group D, n=10) were exposed to Xylene and UVB. The dorsal skin of mice from group B and D were painted with 1ml of Xylene whereas the animals in the group C and D exposed to UVB light for 30 minutes 4 days/week (6 weeks). The result showed that Xylene exposure in group B produced chronic tracheitis, bronchitis with some degenerative lesions in the neurons and glial cells of the brain, no specific lesions were found in the liver, spleen and kidney. UVB exposure in group C caused chronic tracheitis, lesions like lobar pneumonia, bronchopneumonia, and atelectasis, cellular swelling in the liver and kidney and follicular depletion in the spleen. In group D, the lesions became more prominent when animals exposed to both Xylene and UVB. We concluded that Xylene exposure has an adverse effect in some internal organs of mice, but not to all, when combined with UVB exposure it exaggerates its adverse effects on all of the examined organs.

Assessment of Exposure to VOCs among Pregnant Women in the National Children's Study.

Epidemiologic studies can measure exposure to volatile organic compounds (VOCs) using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children’s Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS). We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking) and by observations by a trained data collector (presence of scented products in homes). We found several significant (p < 0.01) relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite N-acetyl-S-(benzyl)-l-cysteine (BMA), and paint use was positively associated with the xylene metabolites 2-methylhippuric acid (2MHA) and 3-Methylhippuric acid & 4-methylhippuric acid (3MHA + 4MHA). A near-significant (p = 0.06) relationship was observed between acrylamide metabolites and observation of incense.

Identification of potential biomarkers for xylene exposure by microarray analyses of gene expression and methylation

Xylene is volatile organic compound that has been reported to increase the incidence of cancer and various diseases related to the immune system, cardiovascular systems, respiratory and reproductive organs. However, there are currently few biomarkers in human cases. Using microarray, we analysed 10 participants for the xylene-exposure group and 10 controls that were not exposed to xylene. The two groups were compared in terms of expression levels and methylation patterns. We identified 6 genes that were down-regulated and hyper-methylated, and 132 that were up-regulated and hypo-methylated in the xylene- exposure group compared to control. We sorted out and 28 biomarker candidates were chosen using DAVID. And then, we used IPA to select the significant potential biomarkers in them. We used network analysis and selected 6 significant genes, and these 6 genes showed altered expression and methylation in xylene-exposure group, suggesting that they are suitable potential biomarkers for xylene exposure.

Determination of Volatile Organic Compounds (VOCs) at Selected Pump Stations in Skudai, Johor Bahru

The determination of volatile organic compounds (VOCs) at selected pump stations in Skudai, Johor Bahru was investigated. About 27 chemicals substances in petrol and 24 chemicals substances in diesel with different concentration have been identified in each pump station. Benzene, toluene, ethylbenzene and xylene (BTEX) and MTBE have been chosen as VOCs of interests because of their toxicity properties that can gives hazardous to human health. The exposures of benzene at all three pump stations during refuelling the liquid fuel have potential to cause cancer riskwhile, ethylbenzene stated as acceptable risk to the people health.As for non-carcinogenic substances, the exposure of toluene, xylene and MTBE were recorded as acceptable risk to the people health at all the studied pump stations. Besides, there is a great correlation between physical environment factors; temperature, relative humidity and wind speed typically with total volatile organic compounds that evaporate into the ambient air during refuelling activities.

Quantum dot/polyvinyl alcohol composite nanofibers membrane as highly sensitive fluorescence quenching-based sensors

Nanofibrous membranes are intensively applied to fabricate advanced intelligent devices like highly sensitive sensors due to their flexibility, high porosity, high surface area and good mechanical and chemical stability. In this work, fluorescent cadmium telluride (CdTe) quantum dots (Q.Ds) were synthesized and then uniformly embedded in poly vinyl alcohol (PVA) nanofibers by electrospinning technique to serve as reversible quenching fluorescence-based sensor to detect the traces of benzene, toluene and xylene vapors selectively at room temperature. Fluorescence analysis suggested that Q.Ds preserve their original fluorescent property in solid nanofiber as if they were in solution. Scanning electron microscopy images showed the uniform diameter of nanofibers. In addition, Fluorescence and transmission electron microscopy (TEM) measurements confirmed the uniform distribution of the Q.Ds into nanofibers structures. The main mechanism of quenching based sensor was designated as electron transfer from thiogalycolic acid (TGA) — capped Q.D surface to target volatile organic compounds (VOC’s) vapors. Fabricated sensor showed selectively sensing upon trace of different target vapors due to the difference in the electronegativity of various VOC’s molecules. For example exposure to more electron withdrawing toluene molecules induces severe quenching effect on fluorescence intensity of Q.D (about 25 %) over xylene exposure. Moreover, it was observed that reducing the diameter of nanofibers enhanced the sensitivity of sensor.

Volatile Organic Compounds Exposure and Health Risks among Street Venders in Urban Area, Bangkok

Air pollution has been for a long time a danger to human health and ecosystems. Many of the world\'s large cities today have bad air quality and can have a lot of health problems because of air pollution. Health risk of volatile organic compounds (VOCs: benzene, toluene, ethylbenzene and xylene (BTEX) and carbonyl compounds; CCs) exposures and their associations with non-specific symptoms of street venders at main roadsides were assessed in Pathumwan Area, central Bangkok, Thailand. A questionnaire was performed for characteristics and non-specific symptoms of street venders. Ambient air and personal air samples were collected at 5 sites of main roadsides and street venders for 8 h during work time. They were collected using 2,4 DNPH cartridge for carbonyl compounds (CCs) by HPLC/UV and activated charcoal tube for BTEX analyses by GC/FID. The results of this study showed that ambient air and personal air samples were not significant different. The life time cancer risk of street venders of benzene, ethylbenzene, formaldehyde and acetaldehyde exposures were 3.12E-06, 8.00E-08, 3.20E-06 and 6.02E-07 which total cancer risk was higher than acceptable limited. But hazard quoteint (HQ) ranges of benzene, xylene, formaldehyde, acetaldehyde and propionaldehyde exposures were lower than 1. The total cancer risk (7.00E-06) of these workers was higher than acceptable limited but hazard index (HI) was lower than limited value. The prevalence of headache, fatigue, dizziness and throat irritation symptoms of street venders were 58.0%, 47.8%, 26.5% and 24.6% respectively which most of them were associated with VOCs exposures.

Traffic-related air pollution. A pilot exposure assessment in Beirut, Lebanon

Traffic-related volatile organic compounds (VOCs) pollution has frequently been demonstrated to be a serious problem in the developing countries. Benzene and 1,3-butadiene (BD) have been classified as a human carcinogen based on evidence for an increased genotoxic and epigenotoxic effects in both occupational exposure assessment and in vivo/in vitro studies. We have undertaken a biomonitoring of 25 traffic policemen and 23 office policemen in Beirut, through personal air monitoring, assessed by diffusive samplers, as well as through the use of biomarkers of exposure to benzene and BD. Personal benzene, toluene, ethylbenzene, and xylene (BTEX) exposure were quantified by GC–MS/MS, urinary trans, trans-muconic acid (t,t-MA) by HPLC/UV, S-phenyl mercapturic acid (S-PMA), monohydroxy-butenyl mercapturic acid (MHBMA) and dihydroxybutyl mercapturic acid (DHBMA) by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC/ESI(-)-MS/MS) in MRM (Multiple Reaction Monitoring) mode. We found that individual exposure to benzene in the traffic policemen was higher than that measured in traffic policemen in Prague, in Bologna, in Ioannina and in Bangkok. t,t-MA levels could distinguish between office and traffic policemen. However, median MHBMA levels in traffic policemen were slightly elevated, though not significantly higher than in office policemen. Alternatively, DHBMA concentrations could significantly distinguish between office and traffic policemen and showed a better correlation with personal total BTEX exposure. DHMBA, measured in the post-shift urine samples, correlated with both pre-shift MHMBA and pre-shift DHMBA. Moreover, there was not a marked effect of smoking habits on DHBMA. Taken together, these findings suggested that DHBMA is more suitable than MHBMA as biomarker of exposure to BD in humans. Traffic policemen, who are exposed to benzene and BD at the roadside in central Beirut, are potentially at a higher risk for development of diseases such as cancer than office policemen.