ASSESSMENT OF NUTRIENT LOADS AND SELF-REMEDIATION: A CASE STUDY OF THE SOUTH RANGSIT CANAL IN THAILAND’S PATHUM THANI PROVINCE

This research investigates the effects of seasonal variability (rainy and dry seasons) and nutrient transfer patterns on the nutrient loads (dissolved inorganic nitrogen (DIN) and orthophosphate phosphorus (P)) and the self-remediation of the south Rangsit canal in Thailand’s central province of Pathum Thani. The results showed that the physicochemical characteristics of the canal water severally varied from season to season, with the ammonium-nitrogen (NH4-N), nitrite and nitrate-nitrogen (NO2+NO3-N) and orthophosphate phosphorus (PO4-P or P) concentrations in the range of 10.79-85.35; 56.70-135.79; and 0.74-5.66 μmol L-1, respectively. The DIN and P loads were 5.05 and 0.40 tons/day in the rainy season (September); and 5.12 and 0.32 tons/day in the dry season (March). The relative remediation efficiency (EFR R) were mostly negative, especially in the dry season, indicating the inadequate self-remediation and nutrient input-output imbalance. The findings also showed that water mass transfer directions influenced the self-remediation and nutrients accumulation in the study area.