ارزیابی خطر زیست‌محیطی لجن فاضلاب به برخی عناصر سنگین تصفیه ‎خانه فاضلاب شهری جنوب تهران

ﺑﻪ ﻣﻨﻈﻮر ارزﯾﺎﺑﯽ وﺿﻌﯿﺖ آﻟﻮدﮔﯽ و ﺧﻄﺮ زﯾﺴﺖ ﻣﺤﯿﻄﯽ ﺑﺮﺧﯽ ﻓﻠﺰات ﺳﻨﮕﯿﻦ در ﻟﺠﻦ ﻫﺎی ﺗﺼﻔﯿﻪ ﺧﺎﻧﻪ ﻓﺎﺿ ﻼ ب ﺷﻬﺮی ﺟﻨﻮب ﺗﻬﺮان ، ﻏﻠﻈﺖ ﻋﻨﺎﺻﺮ ﻣﺲ، ﮐﺮوم، ﺳﺮب، آرﺳﻨﯿﮏ، ﻧﯿﮑﻞ، ﮐﺒﺎﻟﺖ و ﮐﺎدﻣﯿﻢ در ﻟﺠﻦ ﻓﺎﺿﻼب ﺗﻬﯿﻪ ﺷﺪه از 9 اﯾﺴﺘﮕﺎه ﺗﺼﻔﯿﻪ ﺧﺎﻧﻪ اﻧﺪازه ﮔﯿﺮی ﺷﺪ. ﺑﺮاﺳﺎس ﻣﻘﺎدﯾﺮ ﻣﺠﺎز اﺳﺘﺎﻧﺪارد ﻣﺼﺮف ﺟﺎﻣﺪات زﯾﺴﺘﯽ ، ﻣﻘﺎدﯾﺮ ﻣﯿﺎﻧﮕﯿﻦ ﻣﺲ (183 mg.kg-1 ) ﮐﺮوم ،(274mg.kg-1 ) و ﺳﺮب (mg.kg-1 100) بیش از مقادیر مجاز برای لجن درجه c1 و دارای درجه c2 بودند. ﺑﺮای ارزﯾﺎﺑﯽ ﺧﻄﺮ ات ﻓﻠﺰات ﺳﻨﮕﯿﻦ از ﺷﺎﺧﺺ ﻫ ﺎی زﯾﺴﺖ ﻣﺤﯿﻄﯽ اﺳﺘﻔﺎده ﺷﺪ. ﻣﯿﺎﻧﮕﯿﻦ ﺷﺎﺧﺺ ﻫﺎی ﺗﮏ ﻋﺎﻣﻠﯽ زﻣﯿﻦ اﻧﺒﺎﺷﺘﮕﯽ )igeo( و ﺿﺮﯾﺐ ﺧﻄﺮ اﮐﻮﻟﻮژﯾﮑﯽ ﺑﺎﻟﻘﻮه ( eir) ﻧﺸﺎن داد ﮐﻪ ﻣﺲ و ﺳﺮب ﺑﺮای ﺷﺎﺧﺺ igeo و ﮐﺎدﻣﯿﻢ و مس برای ضریب eir ﻣﻬﻤﺘﺮﯾﻦ ﻓﻠﺰات ﺗﺎﺛﯿﺮﮔﺬار در آﻟﻮدﮔﯽ ﻟﺠﻦ بودند. ﻣﻘﺪار ﺷﺎﺧﺺ آﻟﻮدﮔﯽ ﺗﮏ ﻋﺎﻣﻠﯽ ) pi( ﮐﺮوم، ﻣﺲ و ﺳﺮب ﮐﻠﯿﻪ اﯾﺴﺘﮕﺎه ﻫﺎ در ﮐﻼس آﻟﻮدﮔﯽ ﮐﻢ ﻗﺮار داﺷﺘ ﻨﺪ. از ﻧﻈﺮ ﺷﺎﺧﺼﻬﺎی ﺗﺮﮐﯿﺒﯽ، ﺷﺎﺧﺺ آﻟﻮدﮔﯽ ﺗﺮﮐﯿﺒﯽ ﻧﻤﺮو )pn( ، ﮐﻠﯿﻪ اﯾﺴﺘﮕﺎه ﻫ ﺎ، ﮐﻼس آﻟﻮدﮔﯽ ﮐﻢ داﺷﺘﻨﺪ . ﺷﺎﺧﺺ ﺧﻄﺮ ﺑﺎﻟﻘﻮه اﮐﻮﻟﻮژﯾﮑﯽ ) ri( ، اﯾﺴﺘﮕﺎه ﻫﺎی 5 و 6، ﮐﻢ ﺧﻄﺮ و ﺳﺎﯾﺮ اﯾﺴﺘﮕﺎه ﻫﺎ دارای ﺧﻄﺮ ﻣﺘﻮﺳﻂ ﺑﻮدﻧﺪ. ﻣﻘﺎﯾﺴﻪ ﺷﺎﺧﺺ ﻫﺎی ﺗﺮﮐﯿﺒﯽ ﻧﺸﺎن داد ﮐﻪ اﯾﺴﺘﮕﺎه ﻫﺎی ﻣﺨﺘﻠﻒ دارای ﮐﻼس ﻫﺎی ﻣﺘﻔﺎوﺗﯽ ﻫﺴﺘﻨﺪ و روﻧﺪ ﮐﻼﺳ ﻬﺎ در دو ﺷﺎﺧﺺ اﻟﺰاﻣﺎ ﻫﻤﺮاﺳﺘﺎ ﻧﯿﺴﺘﻨﺪ . ﺑﺎ ﺗﻮ ﺟ ﻪ ﺑﻪ ﺟﺎﻣﻌﯿﺖ ﺷﺎﺧﺺ ri ﻣﯽ ﺗﻮان ﮔﻔﺖ ﻟﺠﻦ ﮐﻠﯿﻪ اﯾﺴﺘﮕﺎﻫﻬﺎ ﺑﻐﯿﺮ از 5و 6دارای ﺧﻄﺮ ﻣﺘﻮﺳﻂ ﻣﯽ ﺑﺎﺷﻨﺪ . ﻫﻤﭽﻨﯿﻦ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﮐﯿﻔﯿﺖ ﻣﺘﻔﺎوت ﻧﻤﻮﻧﻪ ﻫﺎی ﻟﺠﻦ ﻓﺎﺿﻼب ، اﺳﺘﻔ ﺎده از ﻟﺠﻦ ﺟﻨﻮب ﺗﻬﺮان ﺑﻪ ﻋﻨﻮان ﮐﻮد ﯾﺎ ﺑﻬﺴﺎز ﺗﻮﺻﯿﻪ ﻧﻤﯽ ﺷﻮد

ecological risk evaluation of sewage sludge to some heavy metals from municipal wastewater treatment plant in southern tehran

this study investigates the pollution status and environmental risk posed by heavy metals in sewage sludge (ss) from the south tehran wastewater treatment plant. nine samples were collected and analyzed for cu, cr, pb, as, ni, co, and cd content. concentrations of cu (274 mg/kg), cr (183 mg/kg), and pb (100 mg/kg) exceeded authorized limits for c1 and c2 sludge grades. environmental indicators assessed the risk associated with these metals. single factor indices (geoaccumulation and potential ecological risk) identified cu and pb as the primary contributors to sludge pollution based on igeo, while cd and cu were most responsible according to eir. all stations received low level of contamination grades for cr, cu, and pb based on the pi value index. combined indices revealed slight pollution at all stations, as indicated by the nemerow synthetic pollution index (pn). potential ecological risk index (ri) indicated low risk for stations 5 and 6, and moderate risk for others. comparison of combined indices showed differing risk classifications across stations, and trends between indices were not always consistent. high variability in ss composition across stations suggests that applying ss from the south tehran plant as agricultural fertilizer or soil amendment is not generally recommended