Assessing Heavy Metal Contamination in Surface Sediments in an Urban River in the Philippines

The present study investigated heavy metal contaminations in Mangonbangon River, an urban river of Tacloban City, Philippines.Sediment samples were collected from 14 sampling sites and analyzed for total heavy metal content using acid digestion.Heavy metal concentrations ranged from 76.83-263.63 mg/Kg for Zn, 32.80-131.82mg/Kg for Cr, 29.40-217.06mg/Kg for Cu, 12.08-98.07mg/Kg for Ni, 4.06-25.34mg/Kg for Co and 12934.00-27332.00mg/Kg for Fe.The average enrichment factor (EF) showed moderate and moderately severe enrichment for Zn and Cu, respectively, minor enrichment for Cr, Ni, and Co and no enrichment for Mn.The average contamination factor (CF) of Cu and Zn indicated moderate contamination while Cr, Ni, Mn, Co and Fe showed background concentrations.Results on geoaccumulation index (Igeo) showed that sediments were uncontaminated to moderately contaminated with Cu and Zn whereas Igeo for all other heavy metals indicated no contamination.For the overall pollution, pollution load index (PLI) showed that Mangonbangon River was unpolluted.Based on the comparison of heavy metals concentrations with the consensus-based sediment quality guidelines (SQGs), Zn, Cr, Cu and Ni were likely to result to the deleterious effect on bottom-dwelling organisms.Potential ecological risk index (RI) indicated low ecological risk in the sediments.Multivariate analyses revealed that Cu, Cr, Ni and Fe had common origin or geochemical behaviour and were associated with anthropogenic activities.