Philippine E-Journals

An Assessment of the Physicochemical Parameters of Mananga River, Cebu, Philippines

Mary Joyce L. Flores | Macrina T. Zafaralla

 

Abstract:

The Mananga River today is a source of potable water to meet the demands of a fast growing Cebu metropolis. The physicochemical parameters of Mananga River were studied to assess its water quality status. Six sample collections were done from February to December 2006 in 3 monitoring stations covering the upstream (S1), midstream (S2) and downstream (S3) of Mananga River. Results showed significant spatial variation (p<0.05) in the studied physicochemical parameters except for alkalinity, total phosphates and nitrate-nitrogen (NO3-N). Significant temporal variation (p<0.05) was also observed for the factors except for stream width, biological oxygen demand (BOD5) and total suspended solids (TSS). Flow velocity showed significant positive correlation with discharge, pH, DO and NO3-N, and negative correlation with water temperature and TSS. Water temperature correlated negatively with DO and pH, and positively with TSS, with the latter showing a positive correlation with BOD5. The results implied that water currents play a major role in the distribution of dissolved substances and the suspension of sediments. Water quality of the studied segments of Mananga River progressively decreased downstream and was more pronounced during the dry periods. Results also indicated that the river was receiving loads of organic matter from natural and anthropogenic sources.