روابط آلودگي مس با ويژگي هاي خاكهاي پايين دست معدن مس مزرعه (اهرآذربايجان شرقي)

The Relationships between Cu Contamination and Soil Characteristics in Downstream of Mazra’eh Copper Mine (Ahar-East Azarbaijan

با توجه به نزديكي انباشت مواد باطله معادن به اراضي كشاورزي احتمال انتقال آلاينده ها و آلوده شدن اين اراضي وجود دارد. در اين تحقيق تعداد30 محل در اراضي پايين دست معدن مس مزرعه منطقه اهر-آذربايجان شرقي (در فاصله 10 كيلومتري از سد مواد باطله معدن) كه با مخلوط مواد باطله انتقال يافته از سد مواد باطله و رسوبات بستر رودخانه فصلي مزرعه پوشانده شده بودند، انتخاب و از سه عمق (10-0، 30-10 و 60-30 سانتي متري) خاك ها و نيز رسوبات سطحي نمونه‌هاي مركب تهيه گرديد. به علاوه، شش محل كه سطح آن‌ها با رسوبات پوشيده نشده و در كمينه فاصله از محل‌هاي آلوده قرار داشتند، به‌عنوان شاهد انتخاب شدند. غلظت كل مس در رسوبات سطحي و خاك ها به‌روش آكوارجيا اندازه گيري و ارتباط آن با ويژگي هاي خاك بررسي شد. غلظت مس در رسوبات سطحي پايين‌دست معدن خيلي زياد و به طور متوسط 1116 ميلي‌گرم بر كيلوگرم بود. متوسط ﻏﻠﻈﺖ ﻣﺲ در رﺳﻮﺑﺎت ﺳﻄﺤﯽ ﭘﺎﯾﯿﻦدﺳﺖ ﻣﻌﺪن ﺧﯿﻠﯽ زﯾﺎد و ﺑﻪﻃﻮر ﻣﺘﻮﺳــﻂ 1116 ﻣﯿﻠﯽﮔﺮم ﺑﺮ ﮐﯿﻠﻮﮔﺮم ﺑﻮد. ﻣﺘﻮﺳــﻂ ﻏﻠﻈﺖ ﻣﺲ در ﺧﺎكﻫﺎي آﻟﻮده ﻋﻤﻖﻫﺎي 0-10، 10-30 و 30-60 ﺳــﺎﻧﺘﯽﻣﺘﺮي ﺑﻪﺗﺮﺗﯿﺐ 105، 86/4 و 79/8 ﻣﯿﻠﯽﮔﺮم ﺑﺮ ﮐﯿﻠﻮﮔﺮم ﺑﻮده و در ﻣﻘﺎﯾﺴــﻪ ﺑﺎ ﻏﻠﻈﺖﻫﺎي ﻧﻈﯿﺮ در ﺧﺎكﻫﺎي ﺷــﺎﻫﺪ )ﺑﻪﻃﻮر ﻣﺘﻮﺳــﻂ 48/4 ﻣﯿﻠﯽﮔﺮم ﺑﺮ ﮐﯿﻠﻮﮔﺮم در ﺳــﻪ ﻋﻤﻖ( 13 درﺻــﺪ ﺧﺎكﻫﺎي ﻋﻤﻖ 0-10 ﺳــﺎﻧﺘﯽ ﻣﺘﺮي، ﺗﻤﺎم ﺧﺎكﻫﺎي ﻋﻤﻖ 10-30 ﺳـﺎﻧﺘﯽ ﻣﺘﺮي و 57 درﺻـﺪ ﺧﺎك ﻫﺎي ﻋﻤﻖ30-60 ﺳﺎﻧﺘﯽﻣﺘﺮي ﺑﻪﺗﺮﺗﯿﺐ داراي آﻟﻮدﮔﯽ زﯾﺎد، ﻣﺘﻮﺳﻂ و ﮐﻢ ﺑﻮدﻧﺪ. در ﻫﺮ ﺳــﻪ ﻋﻤﻖ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ، ﻏﻠﻈﺖ ﻣﺲ ﺧﺎك ﺑﺎ ﻏﻠﻈﺖ ﻣﺲ رﺳــﻮب ﺳــﻄﺤﯽ، ﺿــﺨﺎﻣﺖ رﺳــﻮب ﺳــﻄﺤﯽ و ﻇﺮﻓﯿﺖ ﺗﺒﺎدل ﮐﺎﺗﯿﻮﻧﯽ )CEC( ﺧﺎك ﻫﻤﺒﺴﺘﮕﯽﻫﺎي ﻣﺜﺒﺖ ﻣﻌﻨﺎدار داﺷﺖ.

Due to the proximity of dumping sites for mine tailings to agricultural lands, the migration of contaminants to these lands is possible. In this study, a total of 30 points along a track line of approximately 10 km in downstream of Mazra’eh copper mine (Ahar-East Azarbaijan) covered with a mixture of transferred tailings and bed sediments of Mazra’eh seasonal river were selected. The composite samplings were carried out fromsoils at depths of 0-10, 10-30 and 30-60 cmand fromsurficial sediments. In addition, six non-covered points (controls) with minimum distance from the sampling points were selected. The total concentrations of copper in surficial sediments as well as soils were determined using aqua regia method. Then, the relationships between these concentrations and soil properties were assessed. The results showed very high concentrations of copper (1116 mg kg-1, on average) in the surficial sediments. The concentrations of copper in the soil depths of 0-10, 10-30 and 30-60 cm were 105, 86.4 and 79.8 mg kg-1, respectively. Based on results, 13% of 0-10 cm soils, all of 10-30 cm soils and 57% of 30-60 cm soils were very contaminated, medium contaminated and low contaminated, compared to controls (48.4 mg kg-1, on average for three depths), respectively. Soil copper concentration showed significant positive correlations with surficial sediment copper concentration, thickness of surficial sediment and soil cation exchange capacity (CEC) in all three depths of the studied soils