Composition of wet deposition in Kaynarca, Turkey Cengiz Okay a, *, Bu¨lent O. Akkoyunlu a , Mete Tayanc¸ b a Department of Physics Education, Marmara University, Go ¨ztepe, I : stanbul, Turkey b Department of Environmental Engineering, Marmara University, Go ¨ztepe, I : stanbul, Turkey Received 4 April 2001; accepted 7 September 2001 ‘‘Capsule’’: Cyclones originating from Europe have generally high sulfate and nitrate concentrations and low pH. Abstract In this work, composition of wet deposition in Kaynarca, Turkey is studied by collecting precipitation samples during more than a 2-year period, August 1993–November 1995. Concentrations of the main cations Na + , Mg 2+ , Ca 2+ ,K + , NH 4 + and the main anions Cl  , NO 3  and SO 4 2 together with pH were studied. The average pH value at Kaynarca was near neutral, 5.59. Results indicated that SO 4 2 concentration in precipitation was very high, as was Ca 2+ , neutralizing the acidity. Acidic wet deposition sam- ples were generally obtained in winter. Enrichment factors for sea and soil indicate the strong effects of sea and soil, specifically limestone on the composition of precipitation. Non-sea salt fractions of SO 4 2 were found to range from 0.955 to 0.980, showing the effect of non-sea sources, especially emissions from fossil-fuel combustion, on the pH of samples. Trajectory analysis showed that cyclones originating from northwestern, central and eastern parts of Europe have generally high sulfate and nitrate concentrations and low pH. # 2002 Published by Elsevier Science Ltd. Keywords: Acid precipitation; Wet deposition; Neutralization; Air pollution; Trajectory analysis 1. Introduction The average acidity of precipitation in Scandinavia, northeastern United States and Canada, and parts of Europe and Asia has reached very high levels. This change was primarily due to the increased emissions of sulfur oxides and nitrogen oxides. The major sources of these emissions include power-generating plants, industrial processes, such as ore smelting and petroleum refining, vehicles, and activities of all kinds having fossil fuel combustion. During increased precipitation acidity, especially pH values lower than 4.5, ecological dete- rioration such as forest decline, reduced agricultural productivity, damage to aquatic ecosystems, accelerated weathering of stone structures can take place. This has led to an increased number of wet deposition chemistry studies in recent years (Chan et al., 1985, Andersson and Stokes, 1988). In 1852, the English chemist Robert Angus Smith coined the term ‘‘acid rain’’ to refer to the effect that industrial emissions had on precipitation in the British Midlands (Lutgens and Tarbuck, 1998). Nearly a cen- tury and a half later, this phenomenon is the focus of research for many environmental scientists as well as a topic having substantial international political impor- tance. The World Health Organization (WHO) recom- mends that ambient air should be regularly monitored for aerosol acidity when aerosol levels exceed 10 mg/m 3 (WHO, 1987). Title IV of the Clean Air Act of 1990 was the first law in USA history to address the acid deposi- tion problem (Lynch et al., 2000). Canada and the USA signed a treaty mandating reductions in both sulfur dioxide and nitrogen oxide levels. In 1991, the European Community countries and 29 other countries signed the Convention on Environmental Impact Assessment in a Transboundary Context which regulates the long-range transport of pollutants (Canter, 1996). In the 1990s, several acid precipitation studies were conducted for various locations in Turkey. Al-Momani et al. (1995 a, b) analyzed precipitation samples col- lected during January–December 1992 in Antalya and February–December 1994 in I : zmir. They found average pH values of 5.64 and 5.17 for the precipitation of I : zmir and Antalya, respectively. Another study in the capital 0269-7491/02/$ - see front matter # 2002 Published by Elsevier Science Ltd. PII: S0269-7491(01)00292-5 Environmental Pollution 118 (2002) 401–410 www.elsevier.com/locate/envpol * Corresponding author. Tel./fax: +90-216-348-5936. E-mail address: bulentakkoy@marmara.edu.tr (B.O. Akkoyunlu).