دستيابي زيستي جيوه در رسوبات خوريات پتروشيمي و جعفري، بندر امام

The study of mercury bioavailability in sediments of petrochemical and Jafari, Bandar Imam Creeks

زﻣﯿﻨﻪ و ﻫﺪف: ﺑﺎﺗﻮﺟﻪ ﺑﻪ ﺗﺤﺮك ﺟﯿﻮه و ﺳﻤﯿﺖ ﺑﺎﻻي آن و ﺗﻮاﻧﺎﯾﯽ ﺗﺠﻤﻊ آن در زﻧﺠﯿﺮه ﻏﺬاﯾﯽ، آﮔﺎﻫﯽ از ﺳﻄﻮح ﺟﯿﻮه در ﺑﺨﺶﻫﺎي ﻣﺨﺘﻠﻒ ﻣﺤﯿﻂ زﯾﺴﺘﯽ ﺑﺮاي درك و ﭘﯿﺶ ﺑﯿﻨﯽ در ﻣﻌﺮض ﻗﺮارﮔﯿﺮي اﻧﺴﺎﻧﯽ و ارزﯾﺎﺑﯽ ﺧﻄﺮ اﮐﻮﻟﻮژﯾﮑﯽ ﺟﯿﻮه ﺿﺮوري اﺳﺖ. ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﺑﺎ ﻫﺪف ﺗﻌﯿﯿﻦ ﻏﻠﻈﺖ ﮐﻞ و دﺳﺖﯾﺎﺑﯽ زﯾﺴﺘﯽ ﻓﻠﺰ ﺳﻨﮕﯿﻦ ﺟﯿﻮه در رﺳﻮب ﺧﻮرﻫﺎي ﭘﺘﺮوﺷﯿﻤﯽ و ﺟﻌﻔﺮي ﺻﻮرت ﭘﺬﯾﺮﻓﺖ. روش ﺑﺮرﺳﯽ: ﺗﻌﺪاد 27 ﻧﻤﻮﻧﻪ رﺳﻮب از ﺧﻮرﻫﺎي ﭘﺘﺮوﺷﯿﻤﯽ و ﺟﻌﻔﺮي ﺑﺮداﺷﺖ ﺷﺪ. ﭘﺲ از ﻫﻀﻢ ﻧﻤﻮﻧﻪﻫﺎ، ﻣﺤﺘﻮي ﺟﯿﻮه آنﻫﺎ ﺑﺎ اﺳﺘﻔﺎده از دﺳﺘﮕﺎه آﻧﺎﻟﯿﺰ ﺟﯿﻮه اﻧﺪازهﮔﯿﺮي ﺷﺪ. اﺳﺘﺨﺮاج ﺗﺮﺗﯿﺒﯽ رﺳﻮﺑﺎت ﺑﺎ روش BCR اﻧﺠﺎم ﺷﺪ. يافته ها داده هاي غلظت كل جيوه مورد مطالعه در نمونه هاي رسوب با حداقل 2/19 ميلي گرم بر ليتر در ايستگاه 2-8 و حداكثر 45/71 ميلي گرمﻣﯿﻠﯽ ﮔﺮم ﺑﺮ ﻟﯿﺘﺮ در اﯾﺴﺘﮕﺎه 9-1 و ﺑﺎ ﻣﯿﺎﻧﮕﯿﻦ 23/9 ﻣﯿﻠﯽ ﮔﺮم ﺑﺮ ﻟﯿﺘﺮ، ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ رﺳﻮﺑﺎت ﻣﻨﻄﻘﻪ ﻧﺴﺒﺖ ﺑﻪ اﯾﻦ ﻋﻨﺼﺮ آﻟﻮده اﺳﺖ. ﻫﻢﭼﻨﯿﻦ ﻣﯿﺰان ﺟﯿﻮه ﻣﻮﺟﻮد در رﺳﻮﺑﺎت ﻣﻨﻄﻘﻪ از ﺣﺪ اﺳﺘﺎﻧﺪاردﻫﺎي ﺑﯿﻦ اﻟﻤﻠﻠﯽ NOAA ﺑﯿﺶﺗﺮ ﺑﻮد. ﻓﺮم ﻫﺎي ﺷﯿﻤﯿﺎﯾﯽ ﺟﯿﻮه ﺑﺎ اﺳﺘﻔﺎده از روش اﺳﺘﺨﺮاج ﺗﺮﺗﯿﺒﯽ در ﻧﻤﻮﻧﻪ ﻫﺎي رﺳﻮب ﻧﺸﺎن داد ﮐﻪ ﺑﻪ ﺗﺮﺗﯿﺐ 5/10 درﺻﺪ، 5/57 درﺻﺪ، 15/51 درﺻﺪ، 45/79 درﺻﺪ ﺟﯿﻮه ﺑﻪ ﺗﺮﺗﯿﺐ در ﺑﺨﺶ ﺗﺒﺎدل ﭘﺬﯾﺮ، ﮐﺎﻫﻨﺪه، اﮐﺴﺎﯾﻨﺪه و ﻓﺎز ﺑﺎﻗﯽﻣﺎﻧﺪه اﺳﺖ. ﺑﺤﺚ و ﻧﺘﯿﺠﻪﮔﯿﺮي: ﺑﺨﺶ اﻋﻈﻢ ﻓﻠﺰ ﺟﯿﻮه ﺑﺎ ﺑﺨﺶ ﻏﯿﺮ ﺗﺒﺎدلﭘﺬﯾﺮ ﻫﻤﺮاه ﻣﯽﺑﺎﺷﺪ و ﻧﻤﯽﺗﻮاﻧﺪ ﺗﺤﺖ ﺷﺮاﯾﻂ ﻓﯿﺰﯾﮑﻮﺷﯿﻤﯿﺎﯾﯽ ﺣﺎﮐﻢ )pH ﻗﻠﯿﺎﯾﯽ( ﺑﯿﻦ آب و رﺳﻮب ﻣﺒﺎدﻟﻪ ﺷﻮﻧﺪ. ﻓﻠﺰاﺗﯽ ﮐﻪ در ﺑﺨﺶ ﺗﺒﺎدلﭘﺬﯾﺮ ﻗﺮار ﻣﯽﮔﯿﺮﻧﺪ ﺑﻪ ﻋﻠﺖ داﺷﺘﻦ ﭘﯿﻮﻧﺪﻫﺎي اﻟﮑﺘﺮواﺳﺘﺎﺗﯿﮏ ﺿﻌﯿﻒ ﺑﻪ راﺣﺘﯽ ﺗﺤﺖ ﺗﺄﺛﯿﺮ ﻓﺮاﯾﻨﺪﻫﺎي ﺗﺒﺎدل ﯾﻮﻧﯽ)ﺟﺬب/ واﺟﺬب( ﻗﺮار ﻣﯽ ﮔﯿﺮﻧﺪ. ﻣﻘﺎدﯾﺮ ﺑﺎﻻي ﺟﯿﻮهي ﺑﻪ اﯾﺴﺘﮕﺎهﻫﺎي ﻧﺰدﯾﮏ ﺑﻪ ﺧﺮوﺟﯽ ﭘﺴﺎب واﺣﺪ ﮐﻠﺮوآﻟﮑﺎﻟﯽ ﺗﻌﻠﻖ داﺷﺖ ﮐﻪ ﺑﺎ اﻓﺰاﯾﺶ ﻓﺎﺻﻠﻪ از اﯾﻦ اﯾﺴﺘﮕﺎهﻫﺎ ، ﻣﻘﺪار ﺟﯿﻮه ﮐﻞ در رﺳﻮﺑﺎت ﻧﺴﺒﺖ ﺑﻪ ﻣﻨﺎﻃﻖ ﻧﺰدﯾﮏ ﺑﻪ ﺳﺎﺣﻞ، ﮐﺎﻫﺶ ﻣﯽﯾﺎﺑﺪ. ﺑﻨﺎﺑﺮاﯾﻦ ﺟﯿﻮهي ﺗﺠﻤﻊ ﯾﺎﻓﺘﻪ در رﺳﻮﺑﺎت ﻧﺰدﯾﮏ ﺑﻪ ﺳﺎﺣﻞ، از اﯾﻦ ﻣﻨﺎﺑﻊ ﻣﻨﺸﺎ ﮔﺮﻓﺘﻪ و ﺳﻄﺢ آﻟﻮدﮔﯽ ﻓﻠﺰ ﺳﻨﮕﯿﻦ ﺟﯿﻮه در رﺳﻮﺑﺎت ﺑﻪ ﺷﺪت واﺑﺴﺘﻪ ﺑﻪ اﯾﻦ ﻣﻨﺎﺑﻊ اﺳﺖ.

Background and Objective: Due to high mobility and toxicity of mercury in environment and also high accumulation of mercury in food chain, it is important to understand and predict human exposure and ecological risk assessment of mercury. The purpose of this study was to investigate the total concentration of mercury and it's bioavailabilty in sediment of Petrochemical and Ja'fari creeks. Method: In the present study, 27 sediment samples were collected from the sampling sites. Digestion was employed in sample digestion followed by analysis using MOOPAM. samples were analyzed and determined for mercury concentrations by Mercury Analyzer model VM-3000 MERCURY VAPOR MONITOR. Sediments were further investigated for mercury fractions using a three step sequential extraction procedure of BCR. Findings: The concentrations of THg in sediment samples with a minimum of 2.19 and maximum of 45.71 and average of 23.9 milligram per liter show that area is contaminated with mercury according to the National Oceanographic and Atmospheric Administration standard. Discussion and Conclusion: The sequential extraction procedure showed that most Hg in the sediments was largely bound un exchanable phases. Therefore it can not be exchanged between water and sediment under the physicochemical conditions with alkaline pH. The mercury which bound to exchanagble phase can easily desorb and adsorb by sediments. High content of mercury was in station close to chloralkaline factory and with distance, Hg concentration was decreased.