The Chemistry of Precipitation in Israel

AbstractRecent concerns about the rapid deterioration in the quality of water resources in Israel, in addition to the widely documented anthropogenic acidification of precipitation in many parts of the world, have put a “state of the art” review of our knowledge of the chemistry of precipitation in Israel on the order of the day. Electrolyte content in precipitation in Israel is inversely related to average annual precipitation, and thus is 3–6 times higher in southern than in central Israel. The major reason for these differences is the differential enrichment in components of continental origin, such as Ca2+ and HCO3−. The chemical composition of precipitation is determined by the balance between components of marine and continental origin. Na+ and Cl− are the major ions contributed by sea spray, and therefore most of the precipitation exhibits Na/Cl (molar) ratios close to that of seawater. Precipitation in the southern parts of the country is an exception. Other ions of partly marine origin are Mg2+, SO42−, K+, and, to a limited extent, Ca2+. Marine contribution to precipitation decreases with distance from the sea. The most important component of continental origin in precipit