Environmental biomonitoring of water bodies (Estero de Vitas and Estero de Paco) in Metro Manila, Philippines using heavy metal analysis and erythrocyte micronucleus assay in Nile tilapia (Oreochromis niloticus)

• Main Authors: Abdulrahman, Johnray D., Concepcion, Charilen Kei V., Sanchez, Miguel Alvaro S.
• Format: text
• Language: English
• Published: Animo Repository 2018
• Subjects: Bodies of water > Philippines; Bioremediation > Philippines; Nile tilapia > Philippines; Pasig river system; Water > Purification > Biological treatment > Philippines
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/6397
• Institution: De La Salle University

Environmental Bio-monitoring of water bodies to detect the presence of harmful pollutants and their genotoxicity potential is routinely done to assess the environmental state of aquatic ecosystems. In this study, a combination of atomic absorption spectroscopy and the fish micronucleus assay was used to determine and compare the genotoxic potential of water bodies specifically the two Esteros namely- Estero de Vitas and Estero de Paco, which are part of the Pasig River System. The elevated levels of micronuclei and nuclear abnormalities were observed in the erythrocytes of the genetic model, the Nile tilapia (Oreochromis niloticus) exposed to water samples from the two sources tested when compared to a control group indicating the presence of genotoxic and hazardous pollutants in the water bodies of Estero de Paco and Estero de Vitas. Further, the water samples from Estero de Vitas was found to be far more genotoxic as compared to the water samples from Estero de Paco (p<0.05). Estero de Paco is the water body that was rehabilitated by the efforts of various organizations in past years in Philippines. The observed genotoxic effects of the water samples appeared to be related to the physicochemical characteristics studied using Atomic absorption spectroscopy, which showed the presence of heavy metals in the water samples from both sources. The presence of heavy metals in the fish tissue exposed to the water samples from two locations further confirms that the fish in general are absorbing the heavy metals present in the ecosystem. The results establish that the Fish micronucleus test is an effective assay for evaluating the presence of genotoxic pollutants in aquatic environments as a tool for environmental biomonitoring. The lower genotoxicity potential of Estero de Paco clearly demonstrates that the restoration of the Esteros can be an effective approach to control pollution of the water bodies especially the Pasig river system.