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Background and Objective: One of the problems in urban areas is nitrate contamination of ground waters. High nitrate concentration can cause methemoglobinemia, appearing as a risk factor is provided by ground waters. More than 80% of drinking water of Gorgan, Iran. So this investigation was done to determine of nitrate level in ground waters in Gorgan. This study has been carried out for investigation of nitrate rate in drinking water supply networks and not drinking water ground water wells of Gorgan city. Materials and Methods: This discriptive study was done on 43 ground waters and surface water samples which collected in spring and winter, in Gorgan during 2005. K+, Cl-, NO21-, NO31- of samples were analyzed by spectrophotometery method. Results: The chemical analysis of ground waters of drinking water resources of Gorgan city showed significant variation of nitrate between 3.52 to 69.52 mg/l. The rates of nitrate in certain ground waters wells in vicinity of landfills were between 84.48 to 145.2 mg/l which is more than drinking water standards. Nitrate concentration in agricultural lands such as Shast-kula and Garmabdasht aquifers is lower than Ziarate aquifer in vicinity of urban area. Conclusion: Nitrate contamination in aquifers in vicinity of urban area and unsanitary disposal of solid waste substance may result from house sewage effluents and infiltration of landfill leachs to ground water wells.

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Background and Objective: The use of packaged drinking water is on the rise nowadays in most countries, including Iran. Currently, more than 100 different brands of packaged drinking water are produced and distributed in Iran. This study was done to evaluate the quality of Iranian, foreign packaged drinking waters and municipal drinking water in Golestan Province, north of Iran.
Methods: This descriptive-analytical study was done on 56 packaged drinking waters of different Iranian and foreign brands, eight brands produced in Golestan province and a number of municipal drinking water samples were collected from Gorgan and Gonbad Kavous cities in northern Iran. To assess the quality of packaged drinking water and drinking water, their physicochemical parameters were compared with National Iranian Standards 1053 and WHO. Stiff and Piper diagrams were plotted to determine the type and hydrochemical facies of water samples. Gibbs and Schoeller diagrams were used to determine the water chemistry controlling factors of water samples and their water quality for drinking, respectively.
Results: The concentrations of physicochemical parameters (except bicarbonate) were within the range of national drinking water standards 1053 and WHO. The average nitrate concentration in all packaged drinking and drinking water was within the standard range. The fluoride concentration of all packaged drinking waters and drinking water was within the range of WHO standard. However, only 14 samples of all packaged drinking and drinking water samples are within the range of 1053 National Iranian Water Standard. The total concentration of soluble solids and the total hardness of packaged drinking water were within the range of 1053 NW. There was also a significant difference (P<0.05) between the chemical parameters of magnesium, sodium, chloride and nitrate in packaged drinking water produced in Golestan province with the municipal drinking water samples.
Conclusion: The amount of fluoride in drinking water in this study was less than desirable and required fluorination. The quality of packaged drinking water in Golestan province is better than the municipal drinking water.