Comparative water quality analysis of major river tributaries of a large marine ecosystem: The case of Verde Island Passage Marine Corridor, Philippines

摘要

This study presents a comparative analysis of the physicochemical characteristics of the riverine water of seven major tributaries of Verde Island Passage, a large marine ecosystem considered as the "center of the center of marine shore fish biodiversity on earth." With rivers being the probable sources and routes of pollution contaminants, a conservation program improving their water quality need to be formulated to complement with the wider management of a large marine ecosystem. Values of measured water quality parameters such as pH, temperature, conductivity, turbidity, dissolved oxygen and biochemical oxygen demand generally conform to the Philippines' standards. However, relatively higher levels of total suspended solids, total dissolved solids and oil and grease have been observed particularly in rivers with comparatively higher human population concentration, agriculture and industrial activities such as in Batangas province. Overall, the water quality across the major tributaries of Verde Island Passage in the provinces of Oriental Mindoro, Batangas and Marinduque are comparable to each other as no statistically significant difference in terms of the measured water quality parameters have been confirmed based on Kruskal-Wallis test (H=1.615, df=2, p=0.4) and pairwise Mann-Whitney U test (p>0.05). While individual tributaries generally passed the expected river water quality standard, a monitoring system to ensure its maintenance along with a study focusing on the likely cumulative effects of pollution to the Verde Island Passage through time is warranted.