Abstract:
The purpose of the work is to present and discuss newly obtained data for the chemical composition of cloud water (CW) and rain water (RW) at a high-elevation site in Bulgaria. Sampling of CW and RW was organized in 2017 and 2018 during field experiments at Cherni Vrah, the highest peak in Vitosha Mountain. Passive collectors designed and constructed at NIMN were used. All collected samples (118) were analyzed for acidity (pH), conductivity (EC), main anions – SO42-, NO3-, Cl-, ammonium ions (NH4+), macro and micro elements (Na, K, Mg, Ca, Fe, Si, Zn, Cu). The average pH values for both types of samples were in the acidity range (<5.0). The values of EC varied from 5 to 89.2 μS.cm-1 for RW and from 0.7 to 202 μS.cm-1 for CW. The ion composition was dominated by NH4+, Ca, nssSO42- and NO3-, which made up more than 63% of the total ionic content for RW and 75% for CW. The relative contribution of the major compounds to the CW and RW composition is presented and discussed. The effect of long-range transport processes is studied for some selected periods of 2018 using HYSPLIT air mass backward trajectory analysis.