Evaluating heavy metal levels in green mussels (Perna viridis, Linnaeus, 1758) across major farms in Samar, Philippines

Heavy metal contamination in marine environments presents significant threats to both aquaculture and public health. This study aims to assess the concentrations of nickel (Ni), cadmium (Cd), lead (Pb), and mercury (Hg) in green mussels ( Perna viridis ) from various farms across Samar, a region affected by both natural and human activities. The primary goal was to quantify the levels of these metals in mussel samples and compare them to established safety standards to evaluate potential health risks. Using a cross-sectional study design, green mussel samples were collected from four major farming sites in Samar during the 2023 harvesting season. These samples underwent precise heavy metal quantification through Atomic Absorption Spectroscopy (AAS). Concentrations of each metal were measured and averaged across all sites, with a focus on the variance between locations and the possible sources of contamination. The results indicated that average concentrations for Ni, Cd, Pb, and Hg were 3.5 ± 0.8 μg/g, 1.2 ± 0.3 μg/g, 5.0 ± 1.1 μg/g, and 0.6 ± 0.1 μg/g, respectively. Notably, two sites showed Pb and Ni concentrations exceeding the permissible limits of 2.0 μg/g and 1.5 μg/g, respectively. These sites, situated near local fisher ports, highlight a direct connection to human activities related to fishing and coastal livelihoods. The study concludes that the elevated levels of heavy metals at certain sites pose a serious threat to consumer health and the sustainability of mussel farming in the region. It recommends continuous monitoring and the implementation of regulatory measures to reduce discharges from households and small local enterprises for fish products into marine environments. These findings are significant for guiding policy decisions and ensuring the safety and sustainability of the aquaculture industry in Samar. • Heavy metals in green mussels pose risks to health and aquaculture in Samar. • Elevated levels of lead and nickel were found in mussels near local fishing ports. • Cadmium levels in Villareal mussel farms exceeded Philippine safety standards. • Mercury levels in mussels across farms were below safe consumption limits. • Findings guide policy decisions for sustainable aquaculture and public health.