Annali di Chimica, 96, 2006, by Società Chimica Italiana 389 A PRELIMINARY INVESTIGATION OF TOTAL ORGANIC CARBON VARIATION IN INFLUENT AND EFFLUENT OF ISFAHAN (IRAN) WATER TREATMENT PLANT, URBAN NETWORK AND FELLMAN WELLS Karim MOVASSAGHI (°) 1 , Zahra HEMMATIAN 1 , Behrouz AKBARI-ADERGANI 2 and Giovanni PALMISANO 3 1, Department of Chemistry, Isfahan University, Isfahan 81744, Iran. 2, Department of Environmental Health, Isfahan University of Medical Sciences, Isfahan, Iran. 3, Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy. Summary – In this work a series of total organic carbon (TOC) analyses were carried out to analyse the influent and the effluent of a water treatment plant providing Isfahan city in Iran. Other analyses were focused on the determination of TOC in the urban network and Fellman wells (in Isfahan and Dehaghan cities), in order to compare the water quality soon after the treatment with that of circulating water in the city network. Since it supplies water treatment plant, TOC content of Zayandeh- rood River was also compared with the treated water. The obtained results revealed that there were significant differences between TOC content of effluent of water treatment plant and that of the urban network (made with eight different points). In this project all the samples were withdrawn during 2005. It is worth noting that the analyses were carried out with a high precision combustion-infrared method with a confidence limit lower than 0.05. The mean of TOC in Isfahan and Dehaghan Fellman wells were 0.7 and 2.6 mg.l -1 , respectively. The mean of TOC in influent of water treatment plant during June, July and September were 0.703, 1.148, 1.513 mg.l -1 respectively which after treatment process reduced to about 0.7 mg.l -1 . In conclusion it can be said that during the summer with higher consumption of water and increase in vaporizing surface waters, we have accumulation of organic compounds and therefore we have increase in TOC content of various waters. INTRODUCTION The Islamic Republic of Iran, with an average annual rainfall of 240 mm is counted among the arid and semi arid countries of the world. Isfahan is one of the main industrial cities that is located in the center of Iran and it had an average annual rainfall of about 203 mm in 2005 (FIG. 1). (°) Corresponding author; fax: (+98)-311-6689732; e-mail: movassaghi2000@yahoo.it