بررسی خصوصیات فیزیکی، شیمیایی و کانی شناسی گردوغبار شهر اهواز

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانش آموخته کارشناسی ارشد، گروه خاکشناسی، دانشکده کشاورزی، دانشگاه شهید چمران اهواز

2 استاد گروه خاکشناسی، دانشکده کشاورزی، دانشگاه شهید چمران اهواز

3 عضو هیئت علمی دانشگاه شهید چمران اهواز

4 استادیار دانشکده علوم آب، دانشگاه شهید چمران اهواز

چکیده

بیش از دو سوم کشور ایران در شرایط اقلیم بیابانی و نیمه بیابانی قرار دارد. با این حال علی‌رغم اینکه طوفان‌های گرد و غبار یکی از چالش‌های زیست محیطی در این مناطق به ویژه در استان‌های غربی و جنوب غربی می‌باشند، لیکن اطلاعات اندکی در رابطه با خصوصیات و منشاء وقوع این طوفان‌ها وجود دارد. این تحقیق با هدف بررسی خصوصیات فیزیکی و شیمیایی و ترکیب کانی‌شناسی ذرات گردوغبار ترسیب یافته در شهر اهواز در تابستان و پاییز 1390 انجام شد. به این منظور 15 ایستگاه برای نصب تله‌های رسوبگیر تیله‌ای در شهر اهواز انتخاب و هر ماه پس از جمع‌آوری نمونه‌‌های غبار، نرخ ترسیب، ترکیب کانی شناسی، الگوی توزیع اندازه ذرات و غلظت فلزات سرب، کادمیوم و روی، در نمونه‌ی ذرات گردوغبار تعیین گردید. نتایج به‌دست آمده از این مطالعه حاکی از افزایش قابل توجه نرخ ترسیب ذرات گردوغبار در منطقه در زمان بروز طوفان‌های گردوغبار، نسبت به شرایط بدون طوفان گردوغبار می‌باشد؛ همچنین افزایش موضعی نرخ ترسیب برای بعضی از ایستگاه‌ها حاکی از دخالت عوامل محلی مانند وجود زمین-های بایر و عاری از پوشش و پروژه‌های عمرانی رهاشده در رسوب ذرات گردوغبار بود. ترکیب کانی‌شناسی ذرات گرد و غبار عمدتاً شامل کلسیت، کوارتز و فلدسپات می‌باشد. بررسی توزیع اندازه ذرات گردوغبار نیز فراوانی ذرات در اندازه سیلت را نشان داد که البته این توزیع در زمان وقوع طوفان‌های گردوغبار به سمت ذرات ریزتر گرایش داشت. به علاوه، نتایج حاصل از بررسی غلظت فلزات سنگین در ذرات گرد و غبار مورد مطالعه افزایش غلظت این فلزات را در مناطق صنعتی و پرترافیک نشان داد. همچنین با مقایسه غلظت فلزات سنگین در ماه‌های مختلف نمونه‌برداری بیشترین غلظت فلزات سنگین در آذر ماه مشاهده گردید.

کلیدواژه‌ها


عنوان مقاله [English]

Physicochemical and mineralogical characteristics of dust particles deposited in Ahvaz city

نویسندگان [English]

  • Behnaz Karimian 1
  • Ahmad Landi 2
  • Saeid Hojati 3
  • Javad Ahadian 4
1 Former M.Sc. student, Department of Soil Science, College of Agriculture, Shahid Cahmran University of Ahvaz
2 Professor, Department of Soil Science, College of Agriculture, Shahid Cahmran University of Ahvaz
4 Assistant Professor, College of Water Sciences, Shahid Cahmran University of Ahvaz
چکیده [English]

More than two thirds of the total area in Iran has been covered by arid and semi-arid regions and climate. Although dust storm is an important environmental issue in these regions, especially in western and southwestern provinces, limited information is available regarding characteristics and sources of such phenomena. This study was carried out to identify deposition rate, particle size distribution, heavy metal (Zn, Pb, and Cd) concentrations, and mineralogical composition of dust particles collected using marble dust collector (MDCO) from 15 sampling points in Ahvaz city during a 6 month period in 2011. Results indicated that the average level of deposited particles within the dust storm periods was considerably more pronounced than that of the period’s with no dust storms. The results illustrated that, due to such local factors as the presence of bare lands surrounding the city, and abandoned constructional projects, dust deposition rate in such areas was far more than in other localities. Results also indicated the mineralogical composition of the dust particles mainly comprised of calcite, quartz, and feldspars. Results of particle size distribution analysis showed that the dust particles were mainly silt-sized. However, with occurrence of dust storms, the size of particles became tinier. The highest concentrations of the heavy metals Pb, Cd and Zn were observed downtown and in the industrial neighborhood of the city. In addition, the greatest concentration of the heavy metals was observed in December as compared with the other months of the study period.    

کلیدواژه‌ها [English]

  • Ahvaz
  • Dust
  • Heavy metals
  • MDCO
  • Silt
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