Identification of sources and source regions affecting the chemical composition of rainwater samples collected at Marmaris

In this study, the rainwater chemical composition data (SO42-, NO3-, Cl-, Mg2+, Ca2+, K+, Na+ and NH4+ and pH) that was generated by analyzing the samples collected between 2011 and 2022 in Marmaris station (28.3325 ºE, 36.8859 ºN, 950 m asl) by the General Directorate of Meteorology (MGM) was evaluated by using several statistical techniques. The results showed that the mean pH value was 5.73±0.86 during the study period. The concentrations of parameters determined in the rainwater samples ranged from 3.63±6.43 mg/L for Cl- to 0.011±0.027 mg/L for H+. Chlorine and Ca2+ contributed more to total ion mass as compared to the other ions. The concentrations of sea salt markers (Cl- and Na+) increased during winter due to increased wind speed over the sea. On the other hand, the concentrations major ions (SO42- and NO3-) that formed in the atmosphere because of photochemical reactions increased in summer season. The concentrations of crustal markers (Ca2+, Mg2+ and K+) increased in summer since these parameters become easly aiborne due to dry soil conditions. The long-range transport to Marmaris was also evaluated in this study by combining the trajectoris by cluster analysis technique. It has been found out that there are seven major air masses intercepting at Marmaris. The results show that the dominan air masses corresponding to the trajectories originating from Atlantic Ocean and Black Sea. Finally, factor analysis was performed to find the sources affecting the chemical composition of rainwater at Marmaris station. Neutralization of acidic parameters, sea salt, and biomass combustion and fertilizer use were found to be the main sources.