Environ Monit Assess (2011) 178:63–71 DOI 10.1007/s10661-010-1672-4 Investigation of trihalomethanes formation potential in Karoon River water, Iran Moradali Fooladvand · Bahman Ramavandi · Keyvan Zandi · Mojtaba Ardestani Received: 17 May 2010 / Accepted: 23 August 2010 / Published online: 9 September 2010 © Springer Science+Business Media B.V. 2010 Abstract Organic matters in raw water have a potential to generate harmful disinfection by- products such as trihalomethanes (THMs) dur- ing the chlorination process. The objectives of this study were to investigate the trihalomethane formation potential (THMFP) in Karoon River water and to determine the effect of several fac- tors including total organic carbon (TOC), pH, chlorine dosage, water temperature, and seasonal variation. The results showed that, among all fac- tors, TOC and water temperature have a remark- able effect on THMFP. The experimental results from batch studies indicated that increasing of pH M. Fooladvand The Persian Gulf, Tropical and Infectious Diseases, Research Center, Boushehr University of Medical Sciences, Boushehr, Iran B. Ramavandi (B ) Department of Environmental Health, Faculty of Health, Boushehr University of Medical Sciences, Boushehr, Iran e-mail: ramavandi_b@yahoo.com K. Zandi The Persian Gulf, Marine Biotechnology, Research Center, Boushehr University of Medical Sciences, Boushehr, Iran M. Ardestani Faculty of Environment, Tehran University, Tehran, Iran value yielded a greater THMFP concentration for Karoon River water. THMFP levels of Karoon River water in summer times, when water tem- perature exceeded 26 ◦ C, were 1.2–1.6 times higher than in the spring and fall seasons, when water temperature was below 15 ◦ C. It was found that the measured THMFP at Karoon River water in the spring and fall seasons were very rarely higher than 100 μg/L. Keywords THMFP · Karoon River · Seasonal variation · pH · Chlorine · Water Introduction Often, surface water is reported to contain organic matter derived from natural degradation of some organic substances within the ecological systems and also from human activities. Organic contami- nants in surface water are different from location to location due to the differences in the ecosys- tems and the human activities in each specific location. This organic matter cannot easily be cap- tured using normal water treatment techniques such as coagulation, and therefore it can enter the municipal water treatment system and then distributed through the water supply network. Moreover, during the disinfection process with chlorine, which is a common treatment technique in municipal water supply facilities, the organic