بررسي و تعيين ميزان فلزات(Mo، Cu، Hgو As) درآب و رسوب رودخانه ارس در محدوده استان آذربايجان شرقي

Study on Trace Elements (Mo, Cu, Hg and As) in Water and Sediments in Aras River in East Azerbaijan Province

اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﻪ ﮐﯿﻔﯿﺖ آب رودﺧﺎﻧﻪ ارس ﺑﺮاﺳﺎس ﺑﺮﺧﯽ ﻓﻠﺰات )ﻣﻮﻟﯿﺒﺪن، ﻣﺲ، آرﺳﻨﯿﮏ و ﺟﯿﻮه( در ﭼﻬﺎر اﯾﺴﺘﮕﺎه )از ﺷﻬﺮﺳﺘﺎن ﺟﻠﻔﺎ ﺗﺎ 25 ﮐﯿﻠﻮﻣﺘﺮ ﺑﻌﺪ از ﻣﺮز ﻧﻮردوز( ﻃﯽ ﭼﻬﺎر ﻓﺼﻞ در ﺳﺎل 1394-95 ﭘﺮداﺧﺘﻪ اﺳﺖ. ﺑﺮاي اﯾﻦ ﻣﻨﻈﻮر ﺗﻌﺪاد 32 ﻧﻤﻮﻧﻪ آب و رﺳﻮﺑﺎت ﺳﻄﺤﯽ ﺟﻤﻊ آوري ﺷﺪ. ﻣﯿﺰان ﻓﻠﺰﻫﺎ در ﻧﻤﻮﻧﻪ ﻫﺎي آب و رﺳﻮﺑﺎت ﭘﺲ از آﻣﺎده ﺳﺎزي )اﺳﺘﺨﺮاج و ﻋﻤﻞ ﻫﻀﻢ( ﺑﻮﺳﯿﻠﻪ دﺳﺘﮕﺎه ﺟﺬب اﺗﻤﯽ اﻧﺪازه ﮔﯿﺮي ﮔﺮدﯾﺪ. ﻧﺘﺎﯾﺞ ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ ﻧﺸﺎن داد ﮐﻪ ﺗﻐﯿﯿﺮات ﻏﻠﻈﺖ ﻓﻠﺰات ﻣﻮﻟﯿﺒﺪن، ﻣﺲ، ﺟﯿﻮه و آرﺳﻨﯿﮏ در آب ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺮاﺑﺮ 23/01-0/01 ،40/0-3/0, 0/02-0/81 ، 104/6-23/7 ﻣﯿﮑﺮوﮔﺮم ﺑﺮ ﻟﯿﺘﺮ (ppb) و رﺳﻮﺑﺎت رودﺧﺎﻧﻪ ارس 111/6-0/1 ،482/5-17/5، 0/145-0/0001 ،303/4-46/8 ﻣﯿﮑﺮوﮔﺮم ﺑﺮ ﮔﺮم وزن ﺧﺸﮏ ﻣﯽ ﺑﺎﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ آب رودﺧﺎﻧﻪ ارس ﺑﺮ ﻃﺒﻖ ﻣﯿﺎﻧﮕﯿﻦ ﻏﻠﻈﺖ ﻋﻨﺼﺮ ﻣﺲ در ﮐﻼس III )آﻟﻮدﮔﯽ ﻣﺘﻮﺳﻂ( ﻗﺮار دارد. ﻏﻠﻈﺖ ﻋﻨﺼﺮ ﻣﻮﻟﯿﺒﺪن آب در ﺑﯿﺸﺘﺮ ﻓﺼﻮل ﮐﻤﺘﺮ از ﺣﺪ ﻣﺠﺎز ﺑﻮد. آب رودﺧﺎﻧﻪ ارس ﺑﺮ ﻃﺒﻖ ﻣﯿﺎﻧﮕﯿﻦ ﻏﻠﻈﺖ ﻋﻨﺼﺮ ﺟﯿﻮه و آرﺳﻨﯿﮏ ﺑﻪ ﺗﺮﺗﯿﺐ در ﮐﻼسIV وII ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﺣﺪاﮐﺜﺮ ﻏﻠﻈﺖ ﻋﻨﺼﺮ ﻣﻮﻟﯿﺒﺪن و ﻣﺲ در رﺳﻮﺑﺎت در ﺗﻤﺎم ﻓﺼﻮل در اﯾﺴﺘﮕﺎه ﻫﺎي 3 و 4 ﺛﺒﺖ ﮔﺮدﯾﺪ ﮐﻪ اﺣﺘﻤﺎﻻ ﺑﻪ دﻟﯿﻞ ﺗﺨﻠﯿﻪ ﻓﺎﺿﻼب ﻫﺎي ﻣﻌﺎدن ﺣﺎوي ﻣﻮﻟﯿﺒﺪن، ﻃﻼ و ﺳﺎﯾﺮ ﻓﻠﺰات ﮐﺸﻮر ارﻣﻨﺴﺘﺎن در اﯾﺴﺘﮕﺎه 3 ﺑﻮده اﺳﺖ. ﻏﻠﻈﺖ آرﺳﻨﯿﮏ در رﺳﻮﺑﺎت از اﺳﺘﺎﻧﺪاردﻫﺎي ﺑﯿﻦ اﻟﻤﻠﻠﯽ ﻣﺎﻧﻨﺪ WHO ﺑﯿﺸﺘﺮ ﺑﻮده اﺳﺖ اﻣﺎ ﻏﻠﻈﺖ ﺟﯿﻮه ﮐﻤﺘﺮ ﺛﺒﺖ ﮔﺮدﯾﺪ

This study was conducted to determine water quality of Aras River (Western Azerbaijan), based on metals (Mo, Cu, As, Hg) at four stations (From Julfa to 25km after Nourdos border) during four seasons from 2015 to 2016. Thirty two samples of water and sediments were collected. All samples were analyzed using standard methods (digestion and extraction), using an atomic absorption specphotometer instrument. Results showed that Mo, Cu, As and Hg concentrations in waterand sediments ranged between 0.10-23.01, 3.0-40.0, 0.02-0.81, 23.7-104.6 µg/l, and 0.1-111.6, 17.5-482.5, 0.001-0.145, 46.8-303.6 µg/g.dw, respectively. As a conclusion, water quality of Aras River was classified as class III (moderately polluted) based on mean concentration of Cu. Mo concentration was found to be less than permissible level. Water quality of Aras River was classified as class IV and II based on mean values of Hg and As, respectively. Maximum levels of Mo and Cu in surface sediments were found at stations 3 and 4 during all seasons, which is because of effluents and sewage from Mo, gold and other metal mines from Armenia. Mean concentration of As at surface sediment was higher than recommended standard value, but concentration of Hg was lower than recommended value.