A Preliminary Assessment of Mercury and Cadmium Concentration in Coastal Fish of Island Garden City of Samal, Davao del Norte

Abstract

Heavy metal contamination in marine ecosystems poses potential risks to fisheries resources, seafood safety, and public health because of the persistence and bioaccumulative properties of toxic metals. This study aimed to determine the concentrations of mercury (Hg) and cadmium (Cd) in selected reef fish species collected from the Island Garden City of Samal (IGACOS), Davao del Norte, Philippines, compare the concentrations between the Babak and Kaputian districts, and evaluate the results against international food safety standards. A quantitative, cross-sectional research design was employed using field sampling and laboratory analysis. Fish muscle tissues were collected from twenty sampling stations and analyzed for mercury and cadmium concentrations using Atomic Absorption Spectrophotometry following standardized analytical procedures. Mercury concentrations ranged from 0.0177 to 0.0536 mg·kg⁻¹, while cadmium concentrations ranged from non-detectable levels to 0.0200 mg·kg⁻¹. All measured concentrations remained below the maximum permissible limits established by international standards. Independent samples t-test results indicated no statistically significant differences in mercury (p = 0.276) and cadmium (p = 0.295) concentrations between the two districts. The findings indicate generally low levels of heavy metal contamination in the sampled fishery resources and provide baseline information for environmental monitoring and fisheries management. Continuous monitoring and expanded assessments involving additional contaminants and fish species are recommended to support sustainable coastal resource management and ensure long-term seafood safety.