مطالعات هيدروژئوشيمي و ارزيابي تغييرات كيفيت آب‌هاي زير زميني دشت سنگان - خواف با استفاده از شاخص GQI

Hydrogeochemistry Studies and Assessment of Groundwater Quality Varations in Sngan-Khaf Plain Using GQI Index

ﻣﻨﺎﺑﻊ آب زﯾﺮزﻣﯿﻨﯽ در ﺳﺎلﻫﺎي اﺧﯿﺮ از ﻟﺤﺎظ ﮐﻤﯽ و ﮐﯿﻔﯽ ﺑﻪدﻟﯿﻞ اﻓﺰاﯾﺶ روز اﻓﺰون ﺟﻤﻌﯿﺖ و ﻓﻌﺎﻟﯿﺖﻫﺎي ﺻﻨﻌﺘﯽ و ﮐﺸﺎورزي، ﺑﺎ ﺧﻄﺮآﺳﯿﺐﭘﺬﯾﺮي ﻣﻮاﺟﻪ ﺷﺪه اﺳﺖ. در اﯾﻦ ﻣﻘﺎﻟﻪ ﺗﻐﯿﯿﺮات ﮐﯿﻔﯿﺖ آبﻫﺎي زﯾﺮزﻣﯿﻨﯽ در دﺷﺖ ﺳﻨﮕﺎن ﺧﻮاف ﻣﻮرد ارزﯾﺎﺑﯽ ﻗﺮار ﮔﺮﻓﺖ. ﺑﺎ در ﻧﻈﺮ ﮔﺮﻓﺘﻦ ﺗﻐﯿﯿﺮﭘﺬﯾﺮي ﻣﮑﺎﻧﯽ آﻻﯾﻨﺪهﻫﺎي ﻣﺨﺘﻠﻒ، از ﺷﺎﺧﺺ ﮐﯿﻔﯿﺖ آب زﯾﺮزﻣﯿﻨﯽ GQI ﺑﺮاي ﺗﻮﺻﯿﻒ ﮐﯿﻔﯿﺖ آب زﯾﺮزﻣﯿﻨﯽ اﺳﺘﻔﺎده ﺷﺪ. در ﻣﺤﺎﺳﺒﻪ ﺷﺎﺧﺺ GQI از ﭘﺎراﻣﺘﺮﻫﺎي اﺻﻠﯽ TDS, SO4, Ca, Cl, Mg, Na اﺳﺘﻔﺎده ﺷﺪ. ﻣﻘﺪار اﯾﻦ ﺷﺎﺧﺺ ﺑﺮاي ﻣﻨﻄﻘﻪ ﻣﻮرد ﻧﻈﺮ ﺑﯿﻦ 66/01 ﺗﺎ 81/39 درﺻﺪ ﺑﻪدﺳﺖ آﻣﺪ ﮐﻪ ﻧﺸﺎﻧﮕﺮ ﮐﯿﻔﯿﺖ ﻣﺘﻮﺳﻂ ﺗﺎ ﻗﺎﺑﻞ ﻗﺒﻮل آب ﻣﻨﻄﻘﻪ ﻣﯽﺑﺎﺷﺪ. ﺷﺎﺧﺺ ﮐﯿﻔﯿﺖ آب زﯾﺮزﻣﯿﻨﯽ در ﺟﻬﺖ ﺟﺮﯾﺎن آب زﯾﺮزﻣﯿﻨﯽ ﮐﺎﻫﺶ ﭘﯿﺪا ﮐﺮده اﺳﺖ ﮐﻪ دﻻﻟﺖ ﺑﺮ ﺗﺄﺛﯿﺮ ﺗﻐﯿﯿﺮات ﻟﯿﺘﻮژﻧﯿﮏ و وﺟﻮد ﻻﯾﻪﻫﺎي آﻫﮑﯽ و ﭘﻬﻨﻪﻫﺎي رﺳﯽ در ﻣﻨﻄﻘﻪ دارد

In recent years, quantity and quality of groundwater resources have been faced with the vulnerability risk due to increasing population and industrial and agricultural activities. In this paper, variations of the groundwater quality in Sangan-Khaf plain have been evaluated. With considering the spatial variability of various pollutants, the groundwater quality index (GQI) was used to describe the quality of the groundwater. Main parameters such as TDS, SO4, Ca, Cl, Mg, and Na were used in GQI index calculation. GQI values were obtained between 66.01 to 81.39% which showed that the water quality in the region was in the moderate to good class. The groundwater quality index decreased in the direction of groundwater flow which indicated the effect of lithological changes, carbonate beds and clay zones in the region.