مطالعه مصب ها بعنوان موازنه کننده بار فلزات سنگین بین رودخانه و دریا

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشکده تحصیلات تکمیلی محیط زیست، دانشگاه تهران، تهران، ایران

2 دانشیار دانشکده محیط زیست دانشگاه تهران

چکیده

مصب ها مهم ترین منبع ورود آلودگی ها مختلف به ویژه فلزات سنگین به دریا بشمار می آیند. در این تحقیق ذرات معلق رودخانه سفیدرود جمع آوری شده و در آزمایشگاه تحت فرآیندهای تجزیه کامل و چند مرحله ای قرار می گیرند. به منظور بررسی نقش ناحیه اختلاط مصبی بر سرنوشت فلزات سنگین قبل از ورود به دریا، مصب بصورت آزمایشگاهی شبیه سازی شده و آزمایش های جذب و دفع فلزات سنگین نسبت به ذرات معلق توسط فرآیندهای تجزیه کامل و چند مرحله ای انجام می شود. بر اساس آزمایش جذب و دفع با ورود ذرات معلق به ناحیه اختلاط مصبی، دو فلز منگنز و مس به ترتیب به میزان های 531 و 4/5 پی پی ام از سطح ذرات معلق جدا می شوند، در حالی که دو فلز روی و سرب بترتیب با میزان های 19 و 8 پی پی ام جذب ذرات معلق می شوند. فلز نیکل رفتاری خوددار از خود نشان داده و نه جذب و نه دفع از سطح ذرات معلق می گردد. شاخص RAC نشان داد که در حالی تغییرات محیط مصبی تاثیر ناچیزی بر رفتار دفعی یا جذبی فلزات مس، روی، سرب و نیکل دارد، اما در عین حال تغییرات جزیی فیزیکی یا شیمیایی در محیط مصب میتواند باعث دفع بیشتر این فلز از سطح ذرات معلق شود.

کلیدواژه‌ها


عنوان مقاله [English]

Study of estuaries as load-balancing heavy metals between the River and the Sea

نویسندگان [English]

  • Ali Marefat 1
  • Abdol Reza Karbassi 2
1 Faculty of environment, University of Tehran, Tehran, Iran
2 Tehran university, Faculty of Environment, Tehran
چکیده [English]

Estuaries are considered as the most important source of different pollutants, especially heavy metals toward the lakes, seas and oceans. The research aim is to investigate the heavy metals behavior in the estuarine zone, where a Sea and a River meet each other. In this research, samples of Suspended Particulate Materials (SPMs) and water of Sefidrud River and Caspian Sea were sampled to simulate the estuary physically. Sequential extraction procedure was performed to determined heavy metals concentration in different species. Adsorption-Desorption experiment revealed that during estuarine mixing while manganese and copper are desorbed from SPMs by 531 and 5/4 ppm respectively, zinc and lead are adsorbed by 19 and 8 ppm respectively. Nickel shows a conservative behavior in the Adsorption-Desorption experiment. Risk Assessment Code (RAC) was applied in this study to determine potential of heavy metals release from SPMs as they enter estuarine mixing zone. Results show Mn is likely to release more from SPMs due to environmental changes.

کلیدواژه‌ها [English]

  • estuary
  • Heavy metal
  • Chemical partitioning
  • Suspended Sediment

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