Characterization of rainwater: a comparative study between a housing area and an industrial area of Shah Alam in term of acidity/ Nurul Najihah Nordin

A five weeks study was done for the purpose to compare the characteristics of rainwater between a housing area in Section 9, Shah Alam and an industrial area in Padang Jawa, Shah Alam in term of acidity. Five samples were taken in each area, and the duration for each sample is within a week. By using a multiprobe, physical parameters of rainwater such as temperature and pH were determined. Results shown that temperature of rainwater in industrial area, 26.06+0.09°C was higher than the temperature of rainwater in housing area, 25.21+0.11°C. The pH of rainwater in housing area, 7.27+0.29 was higher than the pH of rainwater in industrial area, 7.12+0.26. The pH of rainwater in both housing and industrial areas were even higher than pH of normal rainwater, 5.6. By using Ion Chromatography, anions F- , Cl- , NO3 - , and SO4 2- and cations Na+ , NH4 + , K+ , Ca2+ , and Mg2+ compositions were determined. Total anions concentration, 13.496+3.137 mg/L was higher in rainwater of industrial area than in rainwater of housing area, 1.601+0.484 mg/L. Meanwhile, total cations, 11.811+1.848 mg/L was higher in rainwater of industrial area than in rainwater of housing area, 1.766+0.76 mg/L. The ratio [cations]:[anions] in rainwater of housing area was 1.1:1, with neutralization factor of basic cations in rainwater of housing area was 1.9392. Meanwhile, The ratio [cations]: [anions] in rainwater of industrial area was 0.8:1, with neutralization factor of basic cations in rainwater of industrial area was 1.2162. In both housing and industrial areas, the basic cations in the rainwater were able to neutralize as well as buffer the acidic effects of the anions. Therefore, this makes the rainwater in both housing and industrial areas were not acidic.