Water Quality Assessment of Laiya River, San Juan, Batangas (2008)

Abstract

Laiya River in San Juan, Batangas serve as a source of water for the residents of Baranggay Laiya Aplaya. The increasing contamination of other water systems had prompted the authorities to take water quality measures to monitor the safety of water for human consumption and public recreation. Thus, the water quality of Laiya River, San Juan, Batangas was assessed in this study using physicochemical parameters which include pH, temperature, Dissolved Oxygen (D.O.), Biological Oxygen Demand (B.O.D), conductivity, color, total solids and total coliform. Algae were also identified as indicator organisms of possible contamination of organic wastes. Climatological data of the sites and the river morphometry were also taken into account. The study was done on a monthly basis, from August to November 2008. Four sampling sites were established which represent the water sources from the upstream part of the river (site 1: Dao and site 2: Panlalaguan), a point after the junction of the first two sites (site 3: Sabang), and the downstream part of the river (site 4: Downstream). Results of the study showed that the water quality of Laiya River in all four sampling sites was within the acceptable range for standard class C fresh waters except for the following parameters: D.O., pH, temperature and total coliform. The following species of algae: Spirogyra sp., Chlamydomonas sp., and Nostoc sp. were present in the water, which could indicate possible presence of organic pollution. The measured characteristic of water on Sabang and Downstream were not similar to its theoretical values which were based on the quality of water from the two upstream sources. This was probably caused by lateral water movement which may originate from any of the following sources: groundwater, domestic wastewaters, and chemical pollutants. Changes in the range (highest and lowest reading of the water parameters) of the quality of water in time during the different sampling periods could be attributed to seasonal changes and/or localized weather conditions.