Water Quality Assessment of Carangan Estero in Ozamiz City, Philippines

Water quality in Esteros is deteriorating due to pollution influx from various human activities. The water quality of Carangan Estero in Ozamiz City was assessed by conducting the physicochemical and bacteriological analyses of water samples. Water sampling from May to June 2013 was done upstream in Barangay Calabayan (Site 1), midstream in Barangay Lam-an (Site 2) and downstream in Barangay San Roque (Site 3). Results showed an increasing temperature downstream that was within the Department of Environment and Natural Resources standards for Class C waters. The low pH in Sites 1 and 2 that ranged from 6.0 to 6.3 did not fall within the standard which could be attributed to the presence of dam and quarry activity upstream and influx of organic wastes midstream. Dissolved oxygen was decreasing downstream and the lowest reading of 2.9 mg/L was below the minimum limit. Biological oxygen demand of 7.2 mg/L in Site 3 exceeded the maximum standard. Total alkalinity in all sites was below the typical level for fresh water and was limited to bicarbonate ions only. Total hardness was increasing downstream. Phosphate concentration did not exceed the standard. Fecal coliform count increased downstream ranging from 4600 to >11,000 MPN/100 mL that exceeded the standard limit. Overall assessment revealed that water quality was deteriorating downstream due to relatively high discharge of organic waste from toilets, kitchen, piggeries, laundry and commercial establishments associated with dense population. A collaborative and sustainable effort of the community is necessary to restore water quality.

 

Keywords: Biological oxygen demand, coliform, pH, phosphate, total alkalinity.