Bioaccessibility and cytotoxicity of arsenic and mercury in cooked seafood: Implications for food safety and human health risk

Seafood is an important component of healthy dietary patterns. However, it can also serve as a dietary source of toxic elements that bioaccumulate in aquatic environments and biomagnify through the food web. This study quantified arsenic (As) and mercury (Hg) in cooked seafood, assessed their bioaccessibility, and evaluated the cytotoxic potential of the bioaccessible fractions using the human intestinal HT-29 cell line. The highest As concentrations were found in bivalves (3.7 ± 0.2 mg kg−1), and the highest Hg concentrations in scabbardfish (0.57 ± 0.01 mg kg−1). The bioaccessibility of As was substantially higher (ranging from 91 ± 2% to 127 ± 6%) than that of Hg (ranging from 4.8 ± 0.3% to 24 ± 8%). The highest bioaccessibility was observed in fresh tuna, 127 ± 6% and 24 ± 8% for As and Hg, respectively. Cytotoxicity assays at 24 h, 48 h, and 72 h indicated that bioaccessible Hg concentrations remained below cytotoxic thresholds. These results highlight the importance of integrating bioaccessibility and toxicological indicators into the evaluation of seafood safety.