Distribution and environmental risk evaluation of heavy metal in core sediments from Lake Çıldır (NE Turkey) Serkan Kükrer & Ahmet Evren Erginal & Sebahat Şeker & Mustafa Karabıyıkoğlu Received: 6 February 2015 /Accepted: 9 June 2015 # Springer International Publishing Switzerland 2015 Abstract This study examined the vertical distri- bution of heavy metals in core sediments taken from Lake Çıldır, Turkey, and their potential eco- logical risks together with organic carbon content and chlorophyll degradation products. Samples were collected from six sampling stations deter- mined along two main transections aligned in north–south and east–west directions. The enrich- ment (EF) and contamination factor (CF), potential ecological risk (PER) index, and pollution load index (PLI) were calculated from the obtained results. For the elements Pb, As, and Cd, a mod- erate level of contamination was detected, whereas a moderate-to-high concentration level was obtain- ed for Mn. The highest contamination level was found for Hg. A pollutant accumulation exists particularly in the surface sediments. Cd and Hg are the only two metals considered to be a poten- tial risk factor in the lake. Keywords Lake Çıldır . Heavy metal pollution . Potential ecological risk . Sediment Introduction Comprising one of the key components of water masses, bottom sediments both provide nutrients to benthic or- ganisms and function as reservoirs for noxious chemical substances (Bodog et al. 1997; Wang et al. 2012). As is well known, various chemical compounds unknowingly or unscrupulously released into nature lead to environ- mental pollution. In coastal areas, heavy metal pollution, amongst other pollutants, constitutes a serious risk of global importance (Kamala-Kannan et al. 2008). These pollutants are permanent, are toxic, and can be hazard- ous to human health when they enter the food chain (Kishe and Machiwa 2003; Luo et al. 2010; Bing et al. 2013; Çevik et al. 2009). Even though major and trace elements constitute micronutrients for organisms (Vrhovnik et al. 2013), over-accumulation of heavy metals may cause ecologi- cal damage (Karadede and Ünlü 2000). The elements Cu and Zn, for example, found in natural waters and sediments, play an important role in aquatic life as a micronutrient, albeit their toxic characteristics are at high concentrations (Bai et al. 2011). Since they cannot easily be metabolized within living organisms, heavy metals accumulate within soft tissues and result in toxic effects (Suresh et al. 2012). In aquatic systems, metals are found as dissolved ions and complexes, as suspended ions, and as solids (Özmen et al. 2004). The metal ions may bind onto organic and inorganic complexes and accumulate as metal hydroxides and sulfides by attaching themselves to minerals or soluble metal salts. In consequence of Environ Monit Assess (2015) 187:453 DOI 10.1007/s10661-015-4685-1 S. Kükrer (*) : A. E. Erginal : M. Karabıyıkoğlu Department of Geography, Faculty of Social Sciences and Humanities, Ardahan University, Ardahan, Turkey e-mail: kukrerserkan@gmail.com S. Şeker Department of Environmental Engineering, Faculty of Engineering, Ardahan University, Ardahan, Turkey