Water Quality Assessment of Four Groundwater Deep Wells (Angat, Philippines) Using Developmental Biomarkers in Zebrafish (Danio rerio) Embryos

Abstract

To obtain an appraisal of the water quality of the groundwater in Angat, Philippines, four groundwater deep wells located around the area (Sulucan, Marungko, Sta. Lucia and Sto. Nino) were selected and evaluated for their toxicity potentials to zebrafish (Danio rerio) embryos. D. rerio embryos were immersed in six-well plates containing water samples from the deep wells. Gastrulation, somite formation, tail detachment, pigmentation, and heartbeat rates were observed. Percent survival in positive control was 80% (48 hr) and 75.55% (96 hr), the negative control had 91.11% (48 hr) and 87.78% (96 hr) and the four well samples ranged from 88.89%-93.33% (48hr) and 84.45%-91.11% (96hr). Percent abnormalities were 20% (48 hr) and 24.45% (96 hr) in the positive control, 8.89% (48 hr) and 12.22% (96 hr) in the negative control and were minimal in all four well samples, ranging from 5.55%-1 1.11% (48hr) and 8.89%-15.55% (96hr). Average heartbeats per minute were 152.67 bpm in the positive control, 132.33 bpm in the negative control and the four well samples ranged from 134.67-154.33 bpm. Hatching in the positive control was 87.78% (96 hr), in the negative control was 85.56% (96 hr) and the four well samples all proceeded accordingly with 87.77%-92.22% success. Rates of mortality and hatching success that were computed using Completely Randomized Design (CRD) and one way ANOVA at p(0.05) and p(0.01) showed that the water samples did not induce significant damage to the embryos. Cytogenetic analysis of metaphase chromosomes of D. rerio larvae showed no results.