The chemical composition of rainwater samples in Indonesia

The assessment of rainwater qualt in Indonesia hasbeen conducted b the Meteorological and GeophysicalAgency (BMG) sice 1995. At present BMG has 27 monitoring sites which collect rainwater samples every sixth day. The analysis of samples are carried out at the BMG Air Quality laboratory in Jakarta to identify the rainwater quality of each site. The acidity level, conductivity, and ionic composition of the rainwater samples are measured and analyzed respec­ tivel using pH meter, conductivity-meter and ion chromato­ graphIn this paper, three monitoring stations, namely BMG,GAW and Cisarua are adopted for a case stud. Results of analysts of the samples collected at the three sites during 1997-1999 indicated different characteristics of each sample which might be attributed to the local effect. On the weekly basis, the average acidity level for these stations during the study period ranges from 3.42 and 6.21, while dominant ions in the rainwater are calcium (Ca), ammonium [NH«), sulfate (SO«), Nitrate (NO») and Chloride (C!).