Investigation of benzene in the fuel stations ambient air in 22 aria of tehran city in 2018

Giti Kashi,1 Giti kashi,2,* Fatemeh sarmast,3

1. Department of Environmental Health, Faculty of Health, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
2. *2Associate professor, Department of Environmental Health, Faculty of Health, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran; E-mail address: g.kashi@yahoo.com & Water Purification Research Centre (WPRC), Tehran Medical Sciences, Islamic Azad University, Tehran, Iran; E-mail assress:
3. 3Buchlor student of Department of Environmental Health, Faculty of Health, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran

Abstract

Introduction

The increase in benzene levels in air is mainly attributed to anthropogenic sources (including fuel combustion (80%) and industrial activities (20%) like solvents application) and natural sources (such as forest fires and volcanic activity). benzene, as the greatest and the most dangerous benzene, toluene, ethylbenzene, and ortho, para, and meta-xylene (btex) compound, has been grouped as a known carcinogenic to humans (group 1) by the international agency for research on cancer (iarc). according to the clean air act, the annual iranian and world health organization standard is set at 5 μg/m3 and 1.5 ppm, respectively. exposure to solvents such as benzene may lead to occurring disorders of the nervous system, liver, kidneys, skin, increased risks of leukemia, bladder, gastrointestinal, and lung cancer. thus, the aim of this study is to determine the seasonal flocculants, spatial variations, risk assessment of benzene in the ambient air of tehran, and urine levels of benzene.

Methods

In this analytical study to sample, cluster random sampling is used. the statistical population of this study is 22 fuel stations (22 districts of tehran) in 2018. the area of the tehran city, tehran province, iran is 730 km2. tehran is a city at latitude 35° 43′ 0″ north, and longitude 51° 24′ 0″ east. 22 fuel stations are located in the center, south, east, west and north of tehran metropolitan area. of the 161 sampling stations identified, 22 stations (13.6% of the sampling station) are selected. ambient and suburb air sampling points are selected. the sampling is carried out at 10-12 am in the period from march to october. air sampling is carried out by direct sampling method to assess benzene concentration in the ambient and indoor air of the site by using a personal sampling pump (skc model, usa) and tedlar bags (skc model, usa), extracted, and analyzed with spme fiber and gas chromatography (agilent 7890n, usa) equipped with a flame ionization detector. we measure the ambient temperature by using rotary thermometer (kasla model, uk). we perform all tests in triplicate (264 test), and report the mean data values. we employ the geographical information system (gis) software package arcgis 9.2 for mapping. all statistical analyses are performed using the spss software version 18 and descriptive statistic (determination of percent and average).

Results

The temperature, relatively humidity, and benzene concentration range of 22 ambient air samples in fuel stations in october are 15-20.6 (19.8±1.8) ̊c and 30-35 (31.3±1.07)%, and 34-288 (137.6±3.3)ppm, respectively. the temperature, relatively humidity, and benzene concentration range of 22 ambient air samples in fuel stations in march are 17-22.8 (21.3±1.9) ̊c and 28-32.3 (27.9±1.7)%, and 28-282 (132.6±3.1)ppm, respectively. the temperature, relatively humidity, and benzene concentration range of 22 suburbs air samples of fuel stations in october are 13-18.9 (17.3±1.3) ̊c and 32-37.5 (33.5±1.1)%, and 24-278 (127.1±2.9)ppm, respectively. the temperature, relatively humidity, and benzene concentration range of 22 ambient air samples in fuel stations in march are 17-22.8 (21.3±1.9) ̊c and 28-32.3 (27.9±1.7)%, and 18-272 (122.1±2.7)ppm, respectively. the urinary concentrations of trans, trans-muconic acid range of 22 fuel station workers at the start in october and march are 1360-11520 (5504±3.6)μg/l and 1120-11280 (5304±3.2) μg/l, respectively. the urinary concentrations of trans, trans-muconic acid range of 22 non-exposed persons at the finish in october and march are 720-8340 (3813±3.6) μg/l and 540-8160 (3663±3.2) μg/l, respectively.

Conclusion

Between urinary concentrations of trans, trans-muconic acid and variables: season, station situation, temperature, relatively humidity, benzene concentration, exposure, and time is seen meaningful statistic relationship (p<0.05). the mean of inhalation lifetime cancer risk for benzene is 12.8 10-6 which is lower than the limits recommended by the united. it is concluded that supervision on transportation, urbanization development, and industrial activities lead to prevent air contamination due to controlling and directorship benzene concentrations. fuel combustion is considered as the most important benzene emission source. it is concluded that fuel station workers perhaps and respiration are the most vulnerable exposed groups and the most main exposure route in fuel station workers, respectively. it is purposed that fuel and vehicle standardization, developing public transportation, and industrial emission control are the most urgent policies. the weakness and power point of this research are the limitation of volume sample and risk assessment, respectively.

Keywords

Ambient air, benzene, fuel stations, gas chromatography, tehran city