Pollutant Load Assessment in the Delineated Drainage Catchment of Tagum Magugpo Creek

Abstract

Urban wastewater pollution poses significant challenges to water quality, ecosystem integrity, and sustainable watershed management, particularly in rapidly urbanizing cities. This study assessed pollutant loads within the delineated drainage catchment of Magugpo Creek, Tagum City, by evaluating biochemical oxygen demand (BOD), nitrate, phosphate, fecal coliform, and pH to characterize wastewater pollution and identify major pollutant-contributing areas. A quantitative descriptive research design was employed using purposive sampling across five transect locations representing upstream, midstream, and downstream sections of the creek. Wastewater samples were collected during the dry season and analyzed through laboratory testing, stream discharge measurements, pollutant load estimation, and statistical analyses, including descriptive statistics, two-way analysis of variance, and Spearman's rank-order correlation. The findings indicate that pH and nitrate generally complied with national water quality standards, whereas BOD, phosphate, and fecal coliform exceeded acceptable limits across most sampling locations, reflecting substantial organic, nutrient, and microbial contamination. Significant positive relationships were observed between BOD and phosphate, and between BOD and fecal coliform, suggesting common pollution sources associated with untreated domestic wastewater. Pollutant load estimation further identified distinct spatial hotspots, with specific transect locations contributing disproportionately to organic, nutrient, and microbial pollution. The study demonstrates that integrating drainage catchment delineation with pollutant load assessment provides a comprehensive basis for identifying priority intervention areas and supports evidence-based watershed management, wastewater planning, and sustainable urban water resource protection.