Clint Joseph A. Villacarlos, Lora Mae G. Villegas, Rosalyn P. Alburo
This study investigates heavy metal bioaccumulation and metallothionein (MT) responses in bivalve mollusks, Dosinia histrio (Gmelin, 1791), Hiatula diphos (Linnaeus, 1771), and Septifer bilocularis (Linnaeus, 1758), collected seasonally along the Balamban coastline in Cebu, Philippines, to assess their potential as bioindicators for evaluating sediment contamination levels. Tissue and sediment samples were analyzed for copper (Cu), chromium (Cr), cadmium (Cd), lead (Pb), and zinc (Zn) using flame atomic absorption spectrophotometry. The study also calculated biota-sediment accumulation factor, enrichment factors (EF), MT induction levels, and sediment pollutions indices, including the geoaccumulation index, contamination factor, pollution load index (PLI), and potential ecological risk index. The results revealed that Zn and Cu were the predominant metals in mollusk tissues, while Cd and Pb levels were notably higher during the wet season, reflecting seasonal variability in metal bioavailability. The highest EF was recorded for Pb during the wet season (5.95), highlighting significant anthropogenic enrichment. The highest Zn accumulation (582±32.0 mg/kg) was observed in D. histrio during the wet season. Sediment Pb levels exceeded FAO/WHO safety thresholds in both seasons, while PLI values above 1 indicated considerable pollution, with Pb and Cd as major ecological risk contributors. These findings emphasize the health risks of consuming these mollusks, particularly during the wet season. Regular monitoring is recommended to mitigate environmental and public health impacts in the Balamban coastal area. © 2025 Iranian Society of Ichthyology.
Madridejos National High School, Department of Education, Division of Cebu Province, Cebu, Madridejos, Philippines; Department of Chemistry, University of San Carlos (USC), Talamban, Cebu City, 6000, Philippines; Biodiversity, Environment, and Natural Resources Research Center (BENRC), Cebu Technological University, Cebu, Argao, 6021, Philippines
