evaluation of physical and chemical quality of groundwater in the villages of qom province and zoning them by gis

background: the aim of this study was to evaluate the physical and chemical quality of groundwater in the villages of qom province during summer 2014, and to compare the results with iran’s standard no. 1053. methods: this research is a descriptive sectional study. during the investigation, one step sampling with the necessary repetitions (if necessary) was performed of each well for evaluation of physical and chemical quality of groundwater in the villages of qom province. spss version 16 and arcgis software were employed for data analysis and data zoning respectively. results: the average concentration of magnesium, sulfate and ammonia in wells water were higher than standard. the average concentration of fluoride was lower than the standard limit. ph and turbidity in all wells were within the standard limit but sulfate in 33.33%, ammonia in 13.33%, magnesium in 10.66%, sodium in 40%, calcium in 5.33%, nitrate in 17.33%, total dissolved solids (tds) in 14.66% and electrical conductivity (ec) in 24% of wells were higher than the standard limit, and fluorine in 98.66% of wells was lower than the standard limit. the results of zoning in the villages of qom province revealed that measured values at most wells were in the maximum amount in central and northeastern areas and minimum amount in southern and western areas. conclusion: this study indicated that most of the physicochemical parameters such as fluoride in almost all villages, and sulfates, chloride, magnesium, sodium, calcium, nitrate, tds and ec in some of the wells did not fall within the permissible limit.