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On the pH and Acid Neutralizing Capacity Profile of Manila Bay Coastal Water Samples in Manila, Philippines

Abstract

For any body of water, its pH and acid neutralizing capacity (ANC) are two important determinants of its overall condition. The ANC has to be high enough to maintain the pH at an optimal level in order to resist acidification and thereby sustain marine life. An assessment of the pH and ANC of Manila Bay coastal waters along Manila and Pasay, Philippines, was done using 16 collected coastal water samples from four different and equally divided geographic sectors along Roxas Boulevard. The pH of the samples was measured using a pH meter while the ANCs were determined via potentiometric titration against sulfuric acid (H2SO4). Results showed that the mean pH of the Manila Bay water samples of 7.84 ± 0.34 was significantly lower compared to the 8.57 mean pH of Laguna de Bay (p < 0.05), while the mean ANC of 112.60 ± 16.53 mg CaCO3/L of the Manila Bay water samples does not significantly differ when compared to the 116 mg CaCO3/L mean ANC of all bodies of seawater (p > 0.05). Further, both the mean pH and ANC values significantly differ among the four different sectors (p < 0.05), and a moderate indirect correlation was identified between pH and ANC of the water samples. More importantly, the coastal waters of Manila Bay have enough buffering components to resist acidification. However, a more holistic study is suggested to accurately assess its capability to indeed sustain marine life.

On the pH and Acid Neutralizing Capacity Profile of Manila Bay Coastal Water Samples in Manila, Philippines (711.2 KiB)