Preliminary physico-chemical and fish survey of two esteros in Manila City

• Main Authors: Orozco, Glorina Divina P., Zafaralla, Macrina, Flavier, Maxima
• Format: text
• Published: Animo Repository 2008
• Subjects: Water quality biological assessment—Philippines—Manila; Environmental Microbiology and Microbial Ecology
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/9122
• Institution: De La Salle University

The deteriorating condition of Manila's esteros has prompted government and private agencies to do research on these polluted streams to provide information for the effective rehabilitation of Manila's river and canal systems. The two major esteros studied were Estero de San Miguel and Estero de Quiapo. Five sampling stations were selected in such a way as to represent a cross section of the variety of conditions that were visually evident in the area. The study was part of the dissertation of the senior author in UPLB for the degree Ph.D. Environmental Science. The physicochemical parameters investigated were: turbidity, water temperature, salinity, electrical conductivity, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), chlorophyll a (chl a), oil & grease, total Kjeldahl nitrogen (TKN) and total phosphorous (TP). The results of analyses indicated that the recommended safe limits for the Class D water resources were all met. The TKN and TP values indicated hypertrophic conditions in all stations. Low chl-a values of 2.58 mg/m3 were indicative of stressful conditions to the primary producers. The Pearson correlation analysis showed a direct variation in all possible pair parameters namely: TKN, TP, DO, BOD, COD, turbidity, chl-a, temp, salinity, conductivity, Secchi depth transparency, including stream velocity and water depth. Four species of fish were found in the esteros, namely, Rasbora maculata (Kataba), Gambusia affinis (mosquito fish), Anabas testudineus (climbing perch or Gurami) and Hypostomus plecostomus (janitor fish). The Shannon diversity index indicated a higher fish diversity in the Estero de Quiapo. The dominant fishes were the mollies and mosquito fishes. These small fishes' habitation of the polluted esteros imply their resilience and adaptation to the stressful conditions there. The Evenness Index showed a higher proportion per species of fish in Estero de San Miguel. Thus, between the two esteros, the Estero de San Miguel is relatively less polluted than Estero de Quiapo. The degree of similarity of the water bodies based on the fish species inhabiting them was 67%.