پديد آورندگان :
سلگي، عيسي دانشگاه ملاير - دانشكده منابع طبيعي و محيط زيست - گروه محيط زيست , شاهوردي نيك، مهدي دانشگاه آزاداسلامي واحد علوم و تحقيقات تهران - دانشكده محيط زيست و انرژي , رمضاني، مهدي دانشگاه آزاداسلامي واحد علوم و تحقيقات تهران - دانشكده منابع طبيعي و محيط زيست
كليدواژه :
آبياري با فاضلاب , فلزات سنگين , خاك , تغييرات عمقي
چكيده فارسي :
زﻣﯿﻨﻪ و ﻫﺪف: ﺑﻪ دﻟﯿﻞ ﮐﻤﺒﻮد آب ﺷﯿﺮﯾﻦ ﺑﺮاي آﺑﯿﺎري، ﻓﺎﺿﻼب ﺑﻪ ﻋﻨﻮان ﯾﮏ ﻣﮑﻤﻞ ﻣﻬﻢ و ﻣﻨﺒﻊ آب ﺟﺎﯾﮕﺰﯾﻦ در دﻫﻪﻫﺎي اﺧﯿﺮ در آﺑﯿﺎري زﻣﯿﻦﻫﺎي ﮐﺸﺎورزي ﻫﺎي اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. آﺑﯿﺎري ﻣﺰارع ﺑﺎ ﻓﺎﺿﻼب ﺳﺒﺐ آﻟﻮدﮔﯽ ﻓﻠﺰات ﺳﻨﮕﯿﻦ در ﺧﺎك، ﻣﺤﺼﻮﻻت ﮐﺸﺎورزي و آبﻫﺎي زﯾﺮزﻣﯿﻨﯽ ﻣﯽ ﺷﻮد، در ﻧﺘﯿﺠﻪ ﺗﻬﺪﯾﺪي ﺑﺮاي ﺳﻼﻣﺖ اﻧﺴﺎن و اﻣﻨﯿﺖ ﻏﺬاﯾﯽ اﺳﺖ. ﻫـﺪف از اﻧﺠـﺎم اﯾـﻦ ﭘﮋوﻫﺶ ﺑﺮرﺳﯽ اﺛﺮ آﺑﯿﺎري ﺑﺎ ﻓﺎﺿﻼب ﺗﺼﻔﯿﻪ ﻧﺸﺪه ﺷﻬﺮي ﺑﺮ ﺗﺠﻤﻊ ﺳﺮب، ﮐﺎدﻣﯿﻮم ﻣﺲ و روي در ﺧﺎك ﺳﻄﺤﯽ و زﯾﺮﺳﻄﺤﯽ و وﯾﮋﮔﯽ ﻫﺎي ﺧﺎك ﺳﻄﺤﯽ ﺑﻮد.
روش ﺑﺮرﺳﯽ در ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ ﺑﻪ ﻣﻨﻈﻮر ﺑﺮداﺷﺖ ﻧﻤﻮﻧﻪﻫﺎي ﺧﺎك ﺳﻄﺤﯽ )20-0 ﺳﺎﻧﺘﯽﻣﺘﺮ( و زﯾﺮ ﺳﻄﺤﯽ )40-20 ﺳﺎﻧﺘﯽﻣﺘﺮ( از اراﺿﯽ ﮐﺸﺎورزي ﺟﻨﻮب ﺷﻬﺮ ﺑﺮوﺟﺮد، 13 ﻣﺰرﻋﻪ آﺑﯿﺎري ﺷﺪه ﺑﺎ ﻓﺎﺿﻼب ﺗﺼﻔﯿﻪ ﻧﺸﺪه ﺷﻬﺮي و 7 ﻣﺰرﻋﻪ آﺑﯿﺎري ﺷﺪه ﺑﺎ آب ﭼﺎه ﮐﻪ ﺑﺎﻓﺖ ﺧﺎك ﻣﺸﺎﺑﻬﯽ داﺷﺘﻨﺪ اﻧﺘﺨﺎب ﺷﺪﻧﺪ. ﻧﻤﻮﻧﻪﻫﺎي ﺧﺎك ﺑﺮاي اﻧﺪازهﮔﯿﺮي ﺳﺮب، ﮐﺎدﻣﯿﻮم، ﻣﺲ ، روي، EC ،pH و ﻣﻮاد آﻟﯽ ﺧﺎك ﻃﺒﻖ روشﻫﺎي اﺳﺘﺎﻧﺪارد آﻧﺎﻟﯿﺰ ﺷﺪﻧﺪ.
ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﺑﺪﺳﺖ آﻣﺪه ﻧﺸﺎن داد ﮐﻪ ﻣﯿﺎﻧﮕﯿﻦ ﻏﻠﻈﺖ ﻫﻤﻪ ﻓﻠﺰات ﺳﻨﮕﯿﻦ در ﺧﺎك ﺳﻄﺤﯽ )ﺑﺠﺰ ﻣﺲ( و زﯾﺮﺳﻄﺤﯽ آﺑﯿﺎري ﺷﺪه ﺑﺎ ﻓﺎﺿﻼب ﺗﺼﻔﯿﻪ ﻧﺸﺪه ﺷﻬﺮي در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﺧﺎك آﺑﯿﺎري ﺷﺪه ﺑﺎ آب ﭼﺎه ﺑﯿﺸﺘﺮ ﺑﻮد. روﻧﺪ ﺗﻐﯿﯿﺮات ﻋﻤﻘﯽ ﻓﻠﺰات در ﺧﺎك آﺑﯿﺎري ﺷﺪه ﺑﻪ اﯾﻦ ﺷﮑﻞ ﺑﻮد: 1-ﺑﺎ ﻓﺎﺿﻼب ﺷﻬﺮي: ﺳﺮب و ﻣﺲ ﺧﺎك زﯾﺮﺳﻄﺤﯽ<ﺧﺎك ﺳﻄﺤﯽ ؛ ﮐﺎدﻣﯿﻮم و روي ﺧﺎك ﺳﻄﺤﯽ<ﺧﺎك زﯾﺮﺳﻄﺤﯽ و 2-ﺑﺎ آب ﭼﺎه: ﺳﺮب و ﻣﺲ ﺧﺎك ﺳﻄﺤﯽ<ﺧﺎك زﯾﺮﺳﻄﺤﯽ ؛ ﮐﺎدﻣﯿﻮم و روي ﺧﺎك زﯾﺮﺳﻄﺤﯽ ﺧﺎك ﺳﻄﺤﯽ.
ﺑﺤﺚ و ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﺑﻪ ﻧﻈﺮ ﻣﯽ رﺳﺪ ﺑﺎﻓﺖ ﺳﺒﮏ ﺧﺎك ﺳﺒﺐ اﻧﺘﻘﺎل اﯾﻦ ﻓﻠﺰات ﺑﻪ ﻻﯾﻪﻫﺎي ﭘﺎﯾﯿﻦ ﺧﺎك ﺷﺪه اﺳﺖ. ﺑﻪ ﻃﻮر ﮐﻠﯽ، ﻏﻠﻈﺖ ﺳﺮب، ﻣﺲ و روي ﭘﺎﯾﯿﻦﺗﺮ از اﺳﺘﺎﻧﺪار FAO/WHO و ﮐﺎدﻣﯿﻮم ﺑﺎﻻﺗﺮ از آن ﺑﻮد. ﺑﻨﺎﺑﺮاﯾﻦ، ﺑﻪ ﻣﻨﻈﻮر ﺣﺼﻮل اﻃﻤﯿﻨﺎن از اﯾﻤﻨﯽ ﻏﺬاﯾﯽ و اﺳﺘﻔﺎده از ﻓﺎﺿﻼب ﺑﺮاي آﺑﯿﺎري، ﻧﻈﺎرت ﻣﺴﺘﻤﺮ و ﮐﻨﺘﺮل آﻟﻮدﮔﯽ ﻣﻮرد ﻧﯿﺎز اﺳﺖ. در ﺿﻤﻦ ﭼﻨﺎﻧﭽﻪ ﺗﺼﻔﯿﻪ ﻓﺎﺿﻼب ﺑﻪ ﻃﻮر ﻣﻨﺎﺳﺐ اﻧﺠﺎم ﺷﻮد، ﺗﺠﻤﻊ ﻓﻠﺰات ﺳﻨﮕﯿﻦ در ﺧﺎك و ﻣﺤﺼﻮﻻت ﮐﺸﺎورزي ﮐﻤﺘﺮ اﺗﻔﺎق ﺧﻮاﻫﺪ اﻓﺘﺎد.
چكيده لاتين :
Background and Objective: Due to the shortage of freshwater for irrigation, wastewater has been used in agricultural irrigation as an important supplement and alternative water resources in recent decades. Irrigation of fields with wastewater can cause potential contamination with heavy metals to soil crops and groundwater, therefore pose a threat to human health and food safety. The aim of this research was to evaluate the effect of irrigation with untreated municipal wastewater on the accumulation of cadmium lead (Pb), (Cd), copper (Cu) and Zinc (Zn) in topsoil and subsoil and top soil properties.
Method: In the present study in order to collection of topsoil (0-20 cm) and subsoil (0-40 cm) samples from south of the Borujerd city, 13 fields irrigated with untreated wastewater and 7 fields irrigated with well water were selected with same soil texture. Soil samples were analyzed by the standard methods for Pb, Cd, Cu, Zn, pH, electrical conductivity (EC), organic matter (OM).
Findings: Findings indicated that untreated wastewater irrigated soil contained higher concentrations of all heavy metals in topsoil (with the exception of Cu) and in subsoil, compared to well water irrigated soil. Trend of depth variations of metals in irrigated soil followed this form: 1-With wastewater: Pb and Cu in subsoil>topsoil; Cd and Zn in topsoil > subsoil and 2-With well water: Pb and Cu in topsoil > subsoil; Cd and Zn in subsoil > topsoil.
Discussion and Conclusion: It seems that light soil texture has been resulted to transport of the metals to deeper soil layers. Overall, the concentrations of Pb, Cu, and Zn were lower than the FAO/WHO standards in soil, while Cd higher than this. Thus, in order to ensure food safety and use of wastewater
for irrigation, continuous monitoring and pollution control is required. Besides, if treatment of wastewater is done appropriately, accumulation of heavy metals in soils and crops will occur less.
