Quality modeling of drinking groundwater using GIS in rural communities, northwest of Iran

Given the importance of groundwater resources in water supply, this work aimed to study quality of drinkinggroundwater in rural areas in tabriz county, northwest of iran. thirty two groundwater samples from different areaswere collected and analyzed in terms of general parameters along with 20 heavy metals (e.g. as, hg and …). thedata of the analyses were applied as an attribute database for preparing thematic maps and showing water qualityparameters. multivariate statistical techniques, including principal component analysis (pca) and hierarchical clusteranalysis (ca) were used to compare and evaluate water quality. the findings showed that hydrochemical faces of thegroundwater were of calcium-bicarbonate type. ec values were from 110 to 1750 ?s/cm, in which concentration ofsalts was high in the east and a zone in north of the studied area. hardness was from 52 to 476 mg/l and caco3 withaverage value of 185.88 ± 106.56 mg/l indicated hard water. dominant cations and anions were ca2+ > na+ > mg2+ > k+ and hco3? > cl? > so42? > no32, respectively. in the western areas, arsenic contamination was observed as high as69 ?g/l. moreover, mercury was above the standard level in one of the villages. eskandar and olakandi villageshad the lowest quality of drinking water. in terms of ca, sampling sites were classified into four clusters of similarwater quality and pca demonstrated that 3 components could cover 84.3% of the parameters. for investigatingarsenic anomaly, conducting a comprehensive study in the western part of studied area is strongly recommended.