1 Department of Environmental Sciences, School of Natural Resources and Environment, Birjand, University of Birjand, Birjand, Iran

2 Regional Water Company of South Khorasan, Birjand, Iran


In the current study, the qualitative status of potable well water was assessed using the groundwater quality index during a course of 4 years (2014-2017). This study was carried out with an aim to monitor the drinking water resources from 12 potable wells on the multivariate analysis basis and for determination of groundwater quality index, the following 13 physicochemical parameters including electrical conductivity, total dissolved solids, pH, total hardness, potassium, fluoride, bicarbonate, chloride, calcium, magnesium, sulphate, and nitrate were used. On the basis of Piper diagram, the results revealed that the type and faces of samples were chloride-sodic and bicarbonate-sodic respectively. Groundwater quality index level in the potable well water of case study area was 42.89 to 56.58 and zone water was in the good and medium range. Besides, 66.7% of the wells were in the good range and 33.3% of wells were in the medium range of water quality index. In this study, potassium and fluoride level in all the zone wells was lower than the ideal level and the electrical conductivity, total dissolved solids, sodium, magnesium and sulphate in all the wells was higher than the ideal range for drinking purposes. Based on this study results, the potable water quality of most of the study area wells generally in 2017 vis-à-vis 2014 had reduced and its main reason was the presence of geology formations, agricultural runoffs and absorbing wells in this zone.

Graphical Abstract

Potable groundwater analysis using multivariate Groundwater Quality Index technique


  • Determined various physico-chemical parameters of groundwater for during a course of 4 years in Qaen County, South Khorasan;
  • The Piper diagram was created for hydrochemical facies and type of groundwater;
  • Principal component analysis of the chemical variables of groundwater is applied to summarize mixtures of correlated parameters;
  • Calculated the groundwater quality index to identify the suitability of groundwater for drinking purposes.


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