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محیط شناسی، جلد ۳۹، شماره ۴، صفحات ۱۲۵-۱۳۶
عنوان فارسی بررسی پراکنش BTEXدر منطقه صنعتی زرقان به کمک GIS
چکیده فارسی مقاله زرقان در 25 کیلومتری شمال شرقی شیراز همواره تحت تأثیر آلاینده‌های متعددی واقع شده است. بنزن، تولوئن و اگزیلن از آلاینده‌های مهم هوا به شمار ‌می‌روند. منابع آلاینده در اطراف زرقان سهم مهمی در ایجاد این آلاینده‌ها دارند. در این مطالعه 10 ایستگاه انتخاب و از طریق جاذب‌های استاندارد‌شده گروه بنزن، تولوئن، اتیل بنزن و اگزیلن (BTEX) به روش پسیو نمونه‌برداری شدند. نمونه‌ها پس از دو هفته تماس با هوای محیط جمع‌آوری و به آزمایشگاه ارسال شدند. با استفاده از نتایج حاصل و موقعیت جغرافیایی محل‌های نمونه‌برداری به کمک نرم‌‌‌افزارArcGIS  و درون‌یابی به روش‌های مختلف، غلظت آلاینده‌ها در نقاط دیگر شهر پیش‌بینی و با استاندارد مقایسه شد. نتایج نشان دادند که غلظت تولوئن، اتیل بنزن و اگزیلن در مناطق مسکونی کمتر از حد مخاطره‌آمیز برای سلامت انسان‌ است. تصاویر به‌دست‌آمده از این درون‌یابی‌ها غلظت نسبتاً زیاد بنزن در حد μg/m3 5/ 21 در شعاع 5/1 کیلومتری از پالایشگاه را نشان داد. مدل‌های GIS و رگرسیون بین نسبت غلظت آلاینده‌های BTEX در ایستگاه میدان امام (حاشیه کوه) و غلظت آن در پالایشگاه ارتباط مستقیم و خطی (ضریب رگرسیون 98/0) را نشان داد که این احتمال را که منشأ اصلی BTEX پالایشگاه شیراز باشد قوت بخشید، اما تأثیر بزرگراه و شهرک صنعتی در مناطق مسکونی ناچیز است. همچنین، محاسبات نشان داد تراکم گازها در زرقان متناسب با وزن مولکولی آن‌هاست و عموماً آلاینده‌های سنگین‌تر قادر به عبور از ارتفاعات صخره‌ای مجاور شهر نیستند و در نتیجه غلظت این آلاینده‌ها در شهر، متراکم و بیشتر می‌شود. پایش این گاز در زرقان و دانستن سهم منابع مختلف آلاینده و شعاع پراکنش این آلودگی از طریق هر منبع در مدیریت و کنترل آلودگی هوا مهم است.
کلیدواژه‌های فارسی مقاله درون‌یابی، زرقان، نمونه‌برداری پسیو، BTEX، GIS،
عنوان انگلیسی GIS-Assisted Investigation on Dispersion of BTEX in Industrial Regions of Zarghan, Iran
چکیده انگلیسی مقاله IntroductionBTEX is a group of polycyclic aromatic hydrocarbons including benzene, toluene, ethylbenzene andxylene. Benzene is released to the atmosphere by both natural and anthropogenic activities. Benzene is emittedto the atmosphere mainly through the petroleum and petrochemical industries. The chronic exposure tobenzene may cause damage to kidneys, liver, lungs, heart, and nerves and also degrade DNA. Benzeneis a group (I) carcinogen. Toluene is used in many industries as a solvent. The exposure to low-tomoderatelevels of toluene can cause dizziness, drowsiness, nausea and hearing loss. The exposure to highlevels of toluene can cause permanent brain and speech damage, unconsciousness and even death.Ethylbenzene is used in the petrochemical industries. It is also used in industries including gas, oil,solvents, pesticides and dyes. Short-term exposure to high level of ethylbenzene can cause symptomssuch as respiratory irritation and neurologic effects. The long-term exposure to ethylbenzene affectsthe blood, liver and kidney. It is classified as a possible human carcinogen (2B) by IARC. Xylene is anaromatic hydrocarbon which is usedw ith benzene and toluene as a catalytic reform er in extraction and oilrefineries. Xylene is a major component of BTEX and is used as a fuel reformer. The inhalation of xylene affectsthe nervous system.Active sampling needs an air sampling pump to actively collect the air through a filter. However, passivesampling does not require a pump and the gases in the air are collected by diffusion. Passive diffusive airsampling is simple with high precision method widely used to monitor large-scales air pollution. GeographicInformation System (GIS) is a powerful tool to assess the contribution levels of BTEX sources. Haddad et al.(2005) used passive sampling to measure BTEX around gas stations in Shiraz.Since the industrial area of Zarghan is affected by numerous air pollution sources, the rapid and precisemonitoring systems are absolutely essential to detect and quantify polluting sources. Therefore, the objectives ofthis study are to (i) determine the dispersion level of BTEX using passive diffusive air sampling and GIStechniques and (ii) assess the contribution level of generating sources of BTEX in the urban areas.Material &MethodsZarghan is located 25 Km northeast of Shiraz, nearby Shiraz -Tehran highway. The town is also surrounded bymany different air pollution sources. Industrial complexes are located about 10 Km from Zarghan. In addition,the mountain in the east side of the town blocked the air flow through the town.We used a diffusive sampler to adsorb BTEX in the air by a tube consisting of adsorbent material. BTEXentered into the adsorbent tube by molecular diffusion. The adsorbent samplers were installed at the elevation of3 to 4 meters from the ground for the period of 17 days (March 2012). After the adsorption period, the samplertubes were sealed and returned to the laboratory for further analysis. After collecti ng the specimens, they weresent to Pasam Company in Switzerland for determination of BTEX. The extraction was done by carbon disulfide(CS2). Ion chromatography was used to analyze BTEX.Since many sources of air pollution are located in the Zarghan residential area, the boundary conditionsampling points were selected by mesh. Due to the small size of the study area, 10 points were selected and onesample was collected at each point. An image of the coverage area was obtained by Google Earth software. Geographical coordinates of 4 pointsof suitable dispersion were determined by the software and used in an Excel file as the ground reference. UsingArcGIS techniqus, the image was processed as the georeferenced map and the result saved in TIFF format with apixel size of 5 m. The data obtained from sampling of BTEX were interpolated using the passive samplingmethod with different methods such as Inverse Weighted Distance to the exponent of 2 (IWD)2, natural nearestneighbor. File Format (TIFF) is a raster image format with a pixel size of 5 m for each specimen (with at least 10sample points). All interpolated layersw ere then extracted by the border of sam ple point's area to performinterpolation for all layers in the same extent. The geographic coverage area of BTEX concentration has beenstudied using different methods of Nearest Neighbor (NN), Inverse Distance Weighted (IWD), and Kringing.BTEX pollution maps were prepared using passive sample interpolation.Discussion and ConclusionThe ambient air quality guidelines for the annual concentrations of benzene in 2005 and 2010 are 10 􀈝gm-3 and3.6 􀈝gm-3, respectively. In most of the sampling stations, benzene concentration was in the standard limit (2.3􀈝gm-3 to 4.8 􀈝gm-3), but the concentrations in the following four stations were considerably high.1. Shiraz oil refinery sampling station with benzene concentration of 21.5 􀂗gm-32. Central old square with benzene concentration of 7.2 􀂗gm-33. Dudej with benzene concentration of 5 􀂗gm-3Data showed that Shiraz oil refinery sampling station with the maximum toluene concentration of 30 􀂗gm-3 ismuch lower than the 24-hour EPA standard limit. In the rest of the sampling stations, toluene concentrationswere lower. The average concentrations of toluene in residential areas of Canada were ranged from 11.5to 34.4􀈝gm-3 which is same as the range of concentration observed in Zarghan. The current study showedthat the concentration of xylene and ethylbenzene in all of the stations were much lower than the harmful levels.The odor of xylene can be recognized in the air at the concentration of 0.008 ppm. Therefore, during themaximum hourly pollution (inversion condition), the concentration of xylene is twice the average andthose who live near the mountain areas are able to detect its odor.The GIS interpolation showed that Shiraz oil refinery is the most important sources of benzene dispersion inthe study area. The relatively high concentration of benzene (21.5 􀂗gm-3) is dispersed in an area where isconfined in a radius of 1.5 Km from the refinery. Fortunately, Zarghan residential areas are not located withinthe affected zone, but according to Kringing and IDW interpolation, the concentration of benzene reached to theamount of 7.2 􀂗gm-3 in the old central square which is located in the center of the city. As seen in the Kringinginterpolation, Shiraz-Tehran highway is not a major source of benzene pollution, but it is expected to have a highconcentration of benzene near the mountain area. The four red stripes represents the high concentration oftoluene belong to Shiraz oil refinery, Zarghan, industrial Park and the highway. The nearest neighbor (NN)interpolation method showed the effects of Shiraz-Tehran highway more clearly. The pollution due toethylbenzene produced by the refinery is extended to a radius of 4.5 Km from the refinery. In addition, this isevident in the red zone of the industrial park and also in the old part of the city near the m ountain. Generally,data show exactly the same dispersion for all 3 isomers of xylenes. Comparing the various interpolation methodsused in the study, the IDW method shows the pronounced role of industrial zones while the Nearest Neighborinterpolation method indicates that the role of the highway is of a greater importance in Zarghan xylenespollution. The highest concentration of air pollutants expected to occur in the area surrounded by themountain. Therefore, the wind direction influences the general movements of the pollutants. Accordingto the GIS maps, the main source of air pollution produced by Shiraz oil refinery is significantlyconcentrated in the old central square station near the mountain area. Since there is no other air pollution sourcesin the area, the reason for increasing air pollution might be due to the trapping of contaminants near themountain area and blocked the air flow. The analysis of regression demonstrated that there is a linearrelationship between the concentration of pollutant at Old Central Square and the concentration in the oilrefinery with the regression coefficient of 0.98.
کلیدواژه‌های انگلیسی مقاله
نویسندگان مقاله منصوره دهقانی |
دانشیار گروه مهندسی بهداشت محیط، دانشکده بهداشت دانشگاه علوم پزشکی شیراز، شیراز، ایران
سازمان اصلی تایید شده: دانشگاه علوم پزشکی شیراز (Shiraz university of medical sciences)

محمد مهدی تقی زاده | mohammad mehdi
استادیار دانشگاه آزاد اسلامی واحد استهبان، استهبان، ایران
سازمان اصلی تایید شده: دانشگاه آزاد اسلامی استهبان (Islamic azad university of estahban)

ابراهیم راستگو |
مربی گروه gis دانشگاه غیرانتفاعی آپادانا، شیراز، ایران

نشانی اینترنتی http://jes.ut.ac.ir/article_36466_10a2934549597cb8e06ceab0c3bc19c8.pdf
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