A study of ionic composition and inorganic nutrient fluxes from rivers discharging into the Cilician Basin, Eastern Mediterranean T. Özsoy & E. Türkoğlu & A. Doğan & D. S. Serin Received: 5 June 2007 / Accepted: 26 September 2007 / Published online: 30 October 2007 # Springer Science + Business Media B.V. 2007 Abstract Present water quality of the perennial rivers; Göksu, Lamas, Efrenk, Tarsus and Seyhan discharging into the Cilician Basin have been inves- tigated. Monthly surface samples collected from three stations downstream of the rivers during the period of October 2004–May 2005 were analyzed to determine ionic composition (Cl - , SO 2À 4 , NO À 3 , PO 3À 4 , NH þ 4 , Ca 2+ , Mg 2+ , Na + and K + ), in addition to measurements of pH, electrical conductivity, alkalinity and total hard- ness. The results have been compared with recom- mended water quality standards. Excluding Göksu, Seyhan and Efrenk river mouths, values for almost all measured parameters, except NH þ 4 , were found to be lower than the desirable limits. In particular, inorganic ammonium, phosphate and nitrate concentrations for Göksu and Seyhan Deltas were 10 1 or 10 2 orders of magnitude higher than the concentrations of the rest of the samples. Temporal variation in levels, primarily observed in PO 3À 4 , suggest the impact of agricultural fertilizers intensively used around Göksu and Seyhan Rivers. According to Turkish National Water Pollu- tion Control Regulations, all rivers were found to be unpolluted with respect to their nitrate, chloride, sulfate and sodium ion contents, while they all could be considered as slightly polluted with respect to their phosphate contents. In contrast to nitrate and phos- phate, ammonium exceeded the maximum permissi- ble limits of water quality criteria in almost all samples. Among the sampled rivers, Tarsus River was better in water quality, with the lowest electrical conductivity, alkalinity, total hardness and nutrient concentration values. Calculated values of elemental inorganic N and P fluxes suggest a substantial increase in nitrogen loads within the last decade, compared to a significant decrease in phosphorus loads of the rivers during the same period. Keywords Cilician Basin . Eastern Mediterranean . Göksu Delta . Inorganic nutrients . Macro-nutrient flux . Water quality assessment Introduction Land use is one of the most important factors controlling water quality of inland waters (Allan and Flecker 1993). Growth in population causes changes in land use patterns and consequently creates adverse effects on the water quality of aquatic resources. During the last few decades, the Mediterranean Coast of Turkey has been subjected to urbanization due to rapid population and industrial growth, agricultural and touristic activities, marine transport linked to the harbours of Mersin, İsken- derun and Taşucu, oil storage and pipeline terminals Environ Monit Assess (2008) 145:17–29 DOI 10.1007/s10661-007-0013-8 T. Özsoy (*) : E. Türkoğlu : A. Doğan : D. S. Serin Department of Chemistry, Mersin University, Çiftlikköy Campus, 33342 Mersin, Turkey e-mail: tozsoy@mersin.edu.tr