Evaluation of the physicochemical parameters on the water quality of the major rivers of Zamboanga del Norte, Philippines

The province of Zamboanga del Norte is endowed with ample water resources which are the primary sources of domestic water for the people in the area. Nevertheless, these water resources face several man-made and industrial activities that generate unwanted pollution. In this study, the physicochemical characteristics of the major rivers of Zamboanga del Norte, Philippines were investigated to know the present condition and assess the overall water quality. The physicochemical parameters that were investigated includes pH, temperature, nitrate-nitrogen (NO₃-N), total suspended solids (TSS), total phosphates ( ${\mathrm{P}\mathrm{O}}_4^{2-}$) and total mercury (Hg). The results of the water analyses revealed that the pH, temperature, nitrate as NO₃-N and the total Hg were within the acceptable range prescribed by Department of Environment and Natural Resources (DENR) and World Health Organization (WHO). However, there was a significant increase of the total suspended solids (TSS) concentrations of 138±58.9,142.3±36.6 and 243±9.5 mg/L, respectively from downstream, midstream and upstream of Sindangan river. The total suspended solids (TSS) concentrations exceeded the permissible limit of 25–65 mg/L recommended by Department of Environment and Natural Resources (DENR). Furthermore, the data showed that all values of the total phosphates for all the river systems exceeded the prescribed limit. Thus, to maintain the water quality of these rivers, proper monitoring and government intervention are very much required.