Abstract—Shirvan is located in plain in Northern Khorasan province north east of Iran and has semiarid to temperate climate. To investigate the annual changes in some qualitative parameters such as electrical conductivity, total dissolved solids and chloride concentrations which have increased during ten continuous years. Fourteen groundwater sources including deep as well as semi-deep wells were sampled and were analyzed using standard methods. The trends of obtained data were analyzed during these years and the effects of different factors on the changes in electrical conductivity, concentration of chloride and total dissolved solids were clarified. The results showed that the amounts of some qualitative parameters have been increased during 10 years time which has led to decrease in water quality. The results also showed that increased in urban populations as well as extensive industrialization in the studied area are the most important reasons to influence underground water quality. Furthermore decrease in water quantity is also evident due to more water utilization and occurrence of recent droughts in the region during recent years. Keywords—Chloride, Electrical Conductivity, Shirvan, Total Dissolved Solids. I. INTRODUCTION ODAY, work on water quality is more necessary compared to the past because of increase in population and increase in water utilization. Especially in the regions with arid and semi-arid climates which are confronted with water as well as soil salinizations. The investigation on water quality is important to prevent these problems . One of the most important limitations in using water resources is their chemical quality. Chemical quality referred to chemical and biological properties which appoint the limits in using the water resources[10]. In developing countries, incorrect execution and the lack of proper regulations in terms of maintenance have caused to contaminate water resources more than before[3]. Some factors called salinity which control water quality, referred to quantity of electric conductivity and concentrations of dissolved ions in the water resources. Deals with these factors are so important to use water resources as irrigation sources in cultivated lands. Using saline water would also leads to increase concentrations of salts in the soil which would may make other complications. Furthermore Hadi Ghorbani is with the Shahrood University of Technology, Shahrood, Iran (corresponding author phone: 0098 274 522 4621; fax: 0098 274 522 4620; e-mail: Ghorbani1969@ yahoo.com). Samira Mohammadi Sadabad is Former Postgraduate Student of Soil Science and was with the Shahrood University of Technology, Shahrood, Iran (phone: 0098 274 522 4621; fax: 0098 274 522 4620; e-mail: mohammadi.samira@ymail.com). decrease in crop yield, specially, with changes in weather conditions and occurrence of drought is expected. Generally, water quality and their changes during the time is very important due to agricultural activities and ignoring this point may cause significant decrease in productivity and development of saline soil as well as extension of desert lands[11]. In the present study, some important annual changes in the quality of groundwater resources in Shirvan plain located at north east of Iran have investigated. II. MATERIALS AND METHODS A. The Study Area Shirvan plain is located in Northern Khorasan province in north east of Iran and it is part of Shirvan _ Ghoochan wide plain in Atrak aquifer area. Average rainfall in this region is 274 mm with average temperature about 10 degree od centigrade semiarid to temperate climate. B. Sampling By means of underground water resources maps and using topography maps, slope side of area was recognized to distinguish upstream and downstream. Then fourteen wells were selected with regard to uniformly distribution on the Shirvan plain. According to sampling time in the past years, groundwater samples were taken in 2006 and 2007 in same month as previous samples have been taken by Northern Khorasan Water Organization during 1998 till 2005. Plastic containers each of 1.5 liters capacity were used to collect of water samples. In order to prevent any unwanted contaminations, the container was first washed with detergent, toughly rinsed with distilled water and then with 5% nitric acid [9] and finally rinsed with distilled water at the end. At each sampling point, the underground water was pumped out and allowed to run for about 20 minutes prior to collection of water sample to ensure the right representative sample is collected. The plastic containers were rinsed twice with water which is to be collected and then the final water samples were taken. The samples were put in a plastic beaker and their temperatures were taken using standard thermometer and the container's lids were immediately replaced to minimize any gas exchange. The samples were thereafter stored in an ice packed cooler during the transportation and stored in a lab fridge at 4 degree of centigrade to analyze. Prior to each laboratory determination, the samples were brought out of the fridge to equilibrate with the environment [2, 7]. Annual Changes in Some Qualitative Parameters of Groundwater in Shirvan Plain North East of Iran T Hadi Ghorbani, Samira Mohammadi Sadabad World Academy of Science, Engineering and Technology International Journal of Environmental and Ecological Engineering Vol:4, No:8, 2010 352 International Scholarly and Scientific Research & Innovation 4(8) 2010 scholar.waset.org/1307-6892/12494 International Science Index, Environmental and Ecological Engineering Vol:4, No:8, 2010 waset.org/Publication/12494