تعیین پتانسیل آلودگی آبخوان تحت‌فشار دشت تبریز

نوع مقاله : مقاله پژوهشی

نویسنده

دانشیارهیدروژئولوژی داشنگاه تبریز

چکیده

تعیین نواحی مستعد آلودگی در آبخوان­­های محبوس کمتر مورد توجه قرار گرفته است. به­طوریکه این پژوهش اولین مورد از این مطالعات در ایران بوده و بر روی آبخوان تحت­فشار دشت تبریز انجام شده است. این آبخوان در معرض آلودگی بوسیله آلاینده های مختلفی می­باشد که ممکن است از مناطق مسکونی، صنعتی و یا کشاورزی آزاد شوند.  ابتدا با استفاده از اطلاعات لاگ­های اکتشافی و خصوصیات هیدروشیمیایی آبخوان، دو سفره آزاد و تحت­فشار از هم تفکیک گردید. به­منظور ارزیابی آسیب­پذیری آبخوان تحت­فشار پنج پارامتر هیدروژئولوژیک مؤثر بر آلودگی آب­های زیرزمینی (سطح پیزومتریک، محیط آبخوان، فاصله مرز سفره تحت­فشار از سفره آزاد، هدایت هیدرولیکی، اندیس پتانسیل آلودگی کل سفره آزاد) معرفی و استفاده گردید. از تلفیق خطی نقشه­های رستری مربوط به پارامترهای فوق با استفاده از تکنیک­های همپوشانی ، میزان اندیس نهایی برای کل منطقه بین 202 و47 برآورد گردید. نتایج مدل نشان داد که بخش شمال شرقی و شرق آبخوان آسیب­پذیری زیاد را شامل می­شود و به­جز بخش­های کمی در غرب منطقه و قسمت­های جنوب منطقه مورد مطالعه که در محدوده با خطر آلودگی کم و کم تا متوسط قرار می­گیرد، سایر قسمت­ها دارای آسیب­پذیری متوسط تا زیاد است. در نهایت مدل به­کمک نقشه پراکندگی مقادیر نیترات صحت­سنجی گردید و با بررسی ارتباط مکانی بین کاربری اراضی و نقشه آسیب پذیری مشخص شد بیشتر نواحی تحت خطر ناشی از منابع آلودگی انسانی می­باشند. در نهایت پیشنهاد می­شود نظارت بیش­تری بر آلایندگی واحد­های صنعتی در مناطقی با آسیب­پذیری بالا اعمال شود و از استقرار واحد­های صنعتی جدید اجتناب گردد.

کلیدواژه‌ها


عنوان مقاله [English]

Evaluation of Pollution Potential of the Confined Aquifer of Tabriz plain

نویسنده [English]

  • AR Vaezihir
Assoc Prof. Hydrogeology, Faculty Member in Dept. of Earth Sciences, University of Tabriz, Iran
چکیده [English]

There is a limited research in the literature on the vulnerability of confined aquifers. In this research as the first one in Iran, the confined aquifer of Tabriz plain has been investigated to evaluate the vulnerablity related to the contaminantion from surface sources. This aquifer is subjected to contamination by various pollutants which may be released from urban areas, industries and farmlands. At first, confined aquifer of the plain has been delineated from unconfined aquifer using study of well information and The hydrochemical Characteristics of aquifer. Five hydrogeological parameters (piezometric level, aquifer media, hydraulic conductivity, distance to confind-unconfined boundary, and pollution potential index of unconfined aquifer) were introduced as the main parameters that impact on the vulnerability of confined aquifers. These parameters were linearly combined using weighted overlay technique to achieve the final index to reflect the vulnerability of the aquifer. The results revealed a vulnerability index value between 47 to 202 indicated that the east and northeast parts of the aquifer had a high vulnerability condition while the west and south parts of the study area had a low and low to moderate risk of pollution. Nitrate concentration distribution map confirmed the results of the vulnerability assessmentand comparing the spatial relationship between the land use and vulnerability zoning maps showed that the most areas of the confined aquifer were under the threat of anthropogenic contaminants. It is recommended to use artificial neural network and fuzzy logic techniqus to verificate the results of this model. In areas with high vulnerability, severe monitoring should be exerted in order to avoidence of pollution from industrial plants, also establishment of new industrial units in the vulnerable zones should be prevented.

کلیدواژه‌ها [English]

  • Keywords: Confined aquifer
  • Piezometric level
  • Pollution potential
  • Tabriz plain
  • Vulnerability
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