Seasonal and Site Variations in Heavy Metals Contaminations in Seawater and Fish Organs and Health Risks Assessment
Coastal ecosystems are increasingly exposed to land-based pollution from tourism, agriculture, and mining, resulting in heavy metal contamination of seawater and marine organisms. This study quantifies cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) concentrations in seawater and in the organs of the commonly consumed fish Auxis thazard and Selar crumenophthalmus in the Tañon Strait, Cebu, Philippines. This research further assesses associated health risks and significant differences in metal levels across organs, seasons, sites, and between species. Fish and seawater samples were collected from three sites, Moalboal, Barili, and Toledo, during wet and dry seasons and prepared following the sampling protocols outlined in previous studies. Health risk assessment was based on the calculated Target Hazard Quotient (THQ), Hazard Index (HI), and Estimated Weekly Intake (EWI). Results revealed that Cd exceeded FAO limits in all fish organs, while Cr exceeded only in the gills, and Pb also exceeded limits and was only discovered in the gills. Cu and Zn were within acceptable levels in both species. Metal concentrations were lowest in muscles and highest in the GIT, and were generally higher during the wet season, except for Zn in the gills and GIT. Metal accumulation between species differed significantly only during the dry season (p<0.05), while across organs at the three sites, metal concentrations did not differ significantly (p<0.05). Only Zn and Cu were detected in low amounts in seawater. Also, results showed no significant health risk. Continued monitoring is suggested, particularly during wet seasons, to support food safety.