ORIGINAL PAPER Groundwater quality degradation of urban areas (case study: Tehran city, Iran) T. Nasrabadi • P. Abbasi Maedeh Received: 30 October 2012 / Revised: 27 April 2013 / Accepted: 17 May 2013 / Published online: 26 June 2013 Ó Islamic Azad University (IAU) 2013 Abstract Groundwater quality of Tehran city is consid- ered in this study. Nine sampling stations were selected, and composite sampling campaign was performed in summer 2012. Groundwater sampled from northern sta- tions appeared to have acceptable characteristics for agri- cultural and drinking uses. The southern station samples did not meet the required guidelines. Concentration of SO 4 2- , Na ? and Cl - obey a sharp ascending trend south- wards. Accordingly, the electrical conductivity of the last station at the very southern areas is more than fifteen times greater than that of the first northern station. Tehran city is located in a semi-arid climate and experiences long hot summers. High rates of evapo-transpiration within urban green spaces and agricultural lands facilitate the saliniza- tion phenomenon in root zones. As a result, excess irriga- tion water eases the consequent percolation into aquifers. Furthermore, saline water intrusion from salt marshes located down south of the city is an expected consequence of wells overpumping. Such case is especially remarkable in hot seasons when an increased urban water demand is observed. Remarkable sulfate concentrations in saline water are mainly justified by percolation of sulfate con- taining fertilizers which are broadly used by local farmers in an uncontrolled manner. Surface run-offs and municipal wastewater leakage may also trigger the salinization process. Keywords Intrusion Á Irrigation Á Salinity Á Tehran city Á Urban groundwater Introduction Water supply in metropolitan cities has been a major concern especially in recent decades (Parkinson and Tayler 2003; Navarro and Carbonell 2007). Different sources have been utilized for such ever increasing demand among which groundwater is proved to be the most reliable one (Howard et al. 2003). Its stable quality, abundance and reasonable exploitation costs are consid- ered as the main advantages of this water source in comparison with other ones (Bauser et al. 2012). In developing countries where remarkable operation and maintenance costs of water treatment plants are not easily affordable, groundwater is the preferred alternative for water supply. The logic is reasonable while it requires no sophisticated treatment process. Furthermore, uncontrolled rapid urbanization accompanied by expansion of suburbs in mentioned regions, make groundwater the most accessible water supply source (Edmunds et al. 2002). Accordingly, major health threats may be exposed to inhabitants by groundwater contamination. This contami- nation may be due to urban storm water infiltration, irri- gation of green spaces, industrial activities and the uncontrolled leakage of wastewater and septic tanks (Robertson et al. 1991; Jeong 2001; Rivett et al. 2002; Dechesne et al. 2004). The aquifers beneath urban areas may become polluted by toxic metals, organic compounds and major anions/cations. Each of mentioned pollutants T. Nasrabadi (&) Graduate Faculty of Environment, University of Tehran, #23, Azin Avenue, Ghods Street, Enghelab Square, zip code: 1417853111 Tehran, Iran e-mail: tnasrabadi@ut.ac.ir P. Abbasi Maedeh Civil–Environmental Engineering, University of Tehran, #23, Azin Avenue, Ghods Street, Enghelab Square, zip code: 1417853111 Tehran, Iran 123 Int. J. Environ. Sci. Technol. (2014) 11:293–302 DOI 10.1007/s13762-013-0340-y