حذف سرب از خاك هاي آلوده توسط گياه ني معمولي (Pharagmites australis)

Phytoremediation of Lead from Contaminated Soil Using Pharagmites Australis

زﻣﯿﻨﻪ و ﻫﺪف: دﻓﻊ ﻓﻠﺰات ﺳﻤﯽ ﻃﯽ ﻓﻌﺎﻟﯿﺖ ﻫﺎي اﻧﺴﺎﻧﯽ، آﻟﻮدﮔﯽ ﺑﺴﯿﺎري از ﺧﺎك ﻫﺎ را ﺑﻪ ﻫﻤﺮاه داﺷﺘﻪ اﺳﺖ. ﺗﺠﻤﻊ ﻓﻠﺰات ﮐﻤﯿﺎب ﻣﻮﺟﺐ از ﺑﯿﻦ رﻓﺘﻦ ﺣﺎﺻﻞﺧﯿﺰي ﺧﺎك و ﺗﺒﺎﻫﯽ ﻣﻨﺎﺑﻊ آب در ﺑﺴﯿﺎري از ﮐﺸﻮرﻫﺎ ﮔﺮدﯾﺪه اﺳﺖ. در ﺳﺎل ﻫﺎي اﺧﯿﺮ روش ﮔﯿﺎه ﭘﺎﻻﯾﯽ ﺑﺎ ﺑﻬﺮه ﮔﯿﺮي از ﮔﻮﻧﻪ ﻫﺎي ﮔﯿﺎﻫﯽ ﻣﺨﺘﻠﻒ از راه ﺣﻞ ﻫﺎي ﺑﺎ اﻫﻤﯿﺖ در ﮐﻨﺘﺮل آﻟﻮدﮔﯽ ﺧﺎك ﺑﻮده اﺳﺖ. روش ﺑﺮرﺳﯽ: در ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ از ﮔﯿﺎه ﻧﯽ ﻣﻌﻤﻮﻟﯽ ) Pharagmites australis( ﺑﺮاي ﺟﺪاﺳﺎزي ﻓﻠﺰ ﺳﺮب از ﺧﺎك ﻫﺎي آﻟﻮده در ﻗﺎﻟﺐ ﺗﺎﻻب ﻣﺼﻨﻮﻋﯽ اﺳﺘﻔﺎده ﺷﺪ. آزﻣﺎﯾﺶ در ﻗﺎﻟﺐ ﻃﺮح ﮐﺎﻣﻼ ﺗﺼﺎدﻓﯽ ﺑﻪ ﺻﻮرت ﻓﺎﮐﺘﻮرﯾﻞ ﺑﺎ دو ﻓﺎﮐﺘﻮر و ﺳﻪ ﺗﮑﺮار اﺟﺮا ﮔﺮدﯾﺪ. ﺑﺮ اﯾﻦ اﺳﺎس ﻣﻘﺪار ﺳﺮب و ﺳﻄﻮح ﻣﺨﺘﻠﻒ ﻏﻠﻈﺖ ﺳﺮب ﮐﻪ ﻣﻮﺟﺐ ﺗﻨﺶ در ﮔﯿﺎه ﻣﯽ ﺷﺪﻧﺪ، ﺑﻪ دﺳﺖ آﻣﺪﻧﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ آزﻣﺎﯾﺶ در ﺷﺮاﯾﻂ ﮔﻞﺧﺎﻧﻪ ﻧﺸﺎن داد ﺑﺎ اﻓﺰاﯾﺶ ﻏﻠﻈﺖ ﺳﺮب در ﺗﯿﻤﺎرﻫﺎي آزﻣﺎﯾﺸﯽ ﻣﯿﺰان ﺟﺬب آن ﺗﻮﺳﻂ ﺑﺎﻓﺖ ﻫﺎي زﯾﺮزﻣﯿﻨﯽ و اﻧﺪام ﻫﺎي ﻫﻮاﯾﯽ ﮔﯿﺎه اﻓﺰاﯾﺶ ﻣﯽ ﯾﺎﺑﺪ ﻫﺮﭼﻨﺪ ﺗﺠﻤﻊ ﻓﻠﺰات در ﺑﺎﻓﺖ ﻫﺎي زﯾﺮزﻣﯿﻨﯽ ﻣﻌﻨﯽ دار ﺑﻮده اﺳﺖ و اﻧﺘﻘﺎل آن و ﺗﺠﻤﻊ در ﺑﺎﻓﺖ ﻫﺎي ﻫﻮاﯾﯽ ﮔﯿﺎه ﺧﯿﻠﯽ ﮐﻢﺗﺮ ﮔﺰارش ﺷﺪه اﺳﺖ. ﻧﺘﺎﯾﺞ ﺗﺠﺰﯾﻪ رﮔﺮﺳﯿﻮن ﻧﺸﺎن داد اﻓﺰاﯾﺶ ﻏﻠﻈﺖ ﺳﺮب در ﺑﺎﻓﺖ ﻫﺎي ﮔﯿﺎه ﻧﯽ ﺗﺎﻻﺑﯽ ﺗﺤﺖ ﺗﺎﺛﯿﺮ ﺳﻄﻮح ﺗﻨﺶ اﯾﻦ ﻓﻠﺰ ﺗﺎﺑﻊ ﯾﮏ ﻣﻨﺤﻨﯽ درﺟﻪ دوم ﺑﺎ ﺿﺮاﯾﺐ ﺗﺒﺎﯾﻦ ﺑﺎﻻي 90% و در ﺳﻄﺢ آﻣﺎري 1 درﺻﺪ ﻣﻌﻨﯽ دار ﮔﺮدﯾﺪ. ﺑﺤﺚ و ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﺑﻪ ﻃﻮر ﮐﻠﯽ ﻧﯽ ﺗﺎﻻﺑﯽ ﮔﯿﺎﻫﯽ ﻧﺴﺒﺘﺎ ﻣﻘﺎوم در ﺑﺮاﺑﺮ ﺗﻨﺶ ﻓﻠﺰ ﺳﻨﮕﯿﻦ ﺳﺮب، داراي ﻓﺎﮐﺘﻮر اﻧﺘﻘﺎل ﭘﺎﯾﯿﻦ و ﻇﺮﻓﯿﺖ ﺑﺎﻻﯾﯽ ﺑﺮاي ﺗﺠﻤﻊ اﯾﻦ ﻓﻠﺰ در رﯾﺸﻪ ﺧﻮد ﻣﯽ ﺑﺎﺷﺪ.

Background and Objective: Antropogenic heavy metals discharge in to the precious environment has been a key burden of modernity. Excess trace elements have driven the fertile soil and water mediums in to unstable and fragile states in many countries. In recent years bio-remediation approaches via various plants species, has been highlited as prior strategies in soil pollution control. Method: The present study aims to assess phytoremediation of Pharagmites australis (common reed) for lead contamination in constructed wetland. Experimental design was performed in an entirely randomized plan having two factors and three replications. Accordingly lead and levels of metal stress were obtained. Findings: According to indoor expriments results, any increment in lead concentration enhances root-shoot metal absorbing. However, impressive accumulation of heavy metals was in roots and its translocation and accumulation in shoot was reported in lesser portions. Results of regression analysis showed concentration increment of lead in P.australis organs under these metal stress condition which was fixed as a quadratic function with R2 >90 (p<0.01). Discussion & Conclusion: P.australis showed high relatively resistant to lead stress. High accumulation capacity for metals in roots and low heavy metal translocation factor were observed during the present study.