Physico-chemical analysis of drinking groundwater of around Tehran by seasonal variation.

: This study was a cross-sectional descriptive study and done in four seasons during April 2011 to March 2012.The objective of the present study was to examine Physico-chemical properties of groundwater around Tehran. The results are also compared with the guideline values of Iranian legislation. A total of 160 drinking water samples were collected from different drinking groundwater around the Tehran. Total Dissolved Solids (TDS), conductivity and pH, were measured by using standard methods and the concentration of ions Cl-, F-, NO3-, NO2-, Br-, SO4(2-), PO4(3-), Ca2+, K+, Na+ and NH4+ in groundwater was performed using Ion chromatography (Metrohm Company, USA) with standard method. This study showed that most of the parameters in groundwater were below the Iranian permissible limit except total dissolved solids (N = 2), conductivity (N = 2), nitrate as NO3- (N = 22), chloride (N = 3), sulphate (N = 2), fluoride (N = 3) and ammonia (N = 8). There were significant differences (p < 0.05) between physico-chemical parameters such as pH, nitrite (NO2-), sodium, potassium, sulphate, ammonia, bromide and phosphate in different seasons. These results are important, not only for the many people who drink groundwater but also for the health supervisory agencies such as Ministry of Health and Institute of Standards and Industrial of Iran (ISIRI) to have more effective control on groundwater.