HomeMindanao Journal of Science and Technologyvol. 9 no. 1 (2011)

Rainwater Chemistry and Biochemical Effects: Basis for Air Quality Assessment of Cagayan de Oro City, Philippines

Romeo M. Del Rosario | Nenita D. Palmes

Discipline: Chemical Engineering



This research attempted to characterize the air quality in the vicinity of what has been considered the densely polluted part of Cagayan de Oro City, Philippines - the Agora-Highway intersection—through the study of the rainwater chemistry and the rainwater biochemical effects. The parameters selected include the following: color, appearance, pH, conductivity, nitrate, suspended solids, chemical oxygen demand (COD), and pro-oxidant activity (in vitro). The bioassays used mongo and lettuce seeds for percent germination and root length. Ipomoea reptans (kangkong) was also used for effect on biomass loss and leaf length change. The same plant was then utilized for biochemical tests which included electrolyte leakage, lipid peroxidation, total phenolics, chlorophylls, and carotenoids. A control was run for each of the bioassays using distilled water (Wilkins Distilled Drinking Water).


In the whole, the results of the physico-chemical analyses showed that the rainwater during the period of the study was generally polluted only to a very minimal extent. The exception was the nitrate level which was somewhat high if considered for human consumption. Further, the bioassay and biochemical test results revealed that relative to the control, the rainwater did not acquire any general toxicity. While there are definitely limitations, on the basis of these data, the overall assessment is that the air during the period of this study was still quite safe from the harmful effects of pollutants.