Cytotoxicity Assessment of Surface Water in La Piñas-Parañaque Critical Habitat and Ecotourism Area (LPPCHEA) using Allium cepa Test

A study was conducted to assess the quality of surface waters in the Las-Piñas-Parañaque Critical Habitat and Ecotourism (LPPCHEA) area, a 175-hectare wetland ecosystem that serves as a sanctuary or haven of many endangered and threatened species of migratory birds and considered as a last mangrove frontier in Metro Manila. Water samples were collected from five sites (Pond 1, Parañaque River, North Lagoon, Las Piñas River, and South Lagoon) and evaluated including a control (tap water) using the Allium cepa test. Root number, root length (shortest and longest), and mitotic index of 120 onion bulbs (Allium cepa var. aggregatum) sample (based on 80% power, medium to large effect size, 5% significance level, and six groups ANOVA test) were assessed under controlled conditions. One-way ANOVA was used to test hypothesis of no treatment effect, with Bonferroni correction applied, and Duncan Multiple Range Test was done following significant ANOVA test. No statistically significant difference was found for the mean number of roots per site/treatment. Statistically significant differences were found for mean shortest root, mean longest root, and mean mitotic index. Results indicated that water samples taken from Las Piñas River and South Lagoon (adjacent sites) were the most polluted.