with reports from Vhernadette A. Oracion and Stephanie Pearl DP Orendain
The Laguna Water District (LWD) showcased the water-testing process in water facilities that ensure the quality of water in Los Banos. The process was available for observation on the first day of the Syensaya, an annual science festival held at the University of the Philippines Los Banos (UPLB) campus.
Water testing is regularly conducted to test for bacteria in common water sources, such as deep wells.
Microbiologist Alma Grace Velasquez used three water samples to demonstrate the water testing process. Of the three samples, two tested positive for coliform and E. coli, common disease-causing bacteria. Among the diseases brought by these organisms is diarrhea.The Colilert-18 Test is used to test water samples in Laguna. Colilert-18 reacts with the enzymes present in the two types of bacteria and will turn the water yellow if coliforms are present. However, for samples with E. coli, the water will turn blue if observed under the UV light.
“Hindi naman nagpa-positive sa coli forms at E. coli ang tubig dito [sa Laguna],” Velasquez assured. However, when during outbreaks involving coliforms and E. coli, the LWD increase the dosage of the disinfectant chlorine dioxide as counter measure.