PRECIPITATION CHEMISTRY AT SINHAGAD-A HILL STATION IN INDIA

The chemistry of precipitation in remote sites such as mountain tops i s of interest in the study of atmospheric pollution and acid rain. The chemical composition measured at mountain site which is away from ind ustrial and urban areas is useful as a reference level and it allows t o determine the extent of anthropogenic contamination. Hence, rain wat er samples were collected at Sinhagad (18 degrees 21'N, 73 degrees 45' E, 1450 m asl) during the monsoon season (June-September) of 1992 and were analysed for major ions. The precipitation samples collected at S inhagad were alkaline in nature and pH values ranged between 5.9 to 6. 76. The ionic composition was dominated by soil dust. The concentratio n of Ca2+ was highest among all the ions. The concentrations of excess SO42- and NO3- were small (23.8 and 15.2 mu eq 1(-1) respectively) co mpared to the values of polluted regions in India. The correlation coe fficient between the ions and pH values was calculated and it was foun d to be maximum in case of Ca2+. Precipitation samples collected at Si nhagad were alkaline owing to higher concentration of Ca2+ and lower l evels of acidic pollutants (SO42- and NO3-).