Probabilistic dietary exposure and cumulative risk of toxic elements in cultivated and wild Mediterranean mussels (Mytilus galloprovincialis) from the Sea of Marmara

Mediterranean mussels ( Mytilus galloprovincialis ) are economically and ecologically vital bivalves, yet statutory compliance with individual element limits does not capture cumulative dietary risks from multi-element mixtures. This study quantified lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) in farmed and wild M. galloprovincialis from 16 stations across the Sea of Marmara during spring and autumn 2025. All concentrations conformed to EU and Turkish Food Codex limits; Hg was below the method detection limit (< 0.015 mg/kg ww). Elemental burdens showed no significant seasonal (Wilcoxon, p = 0.4037) or origin-based differences (Mann–Whitney U = 84.0, p = 0.1200), consistent with a basin-scale ambient baseline, though limited wild composite samples (n = 4) preclude formal demonstration. Correlations between Pb and Cd (rₛ = 0.502, p < 0.01) and Pb and As (rₛ = 0.445, p < 0.05) suggest shared maritime-urban emission pathways. Deterministic screening under national (0.33 g/day) and European (3.12 g/day) scenarios yielded negligible hazard indices (HI = 0.0046 and 0.0430). Monte Carlo simulations (100,000 iterations) confirmed negligible risk for average consumers (20 g/day; P(HI > 1) < 0.001%), whereas high-intake consumers (70 g/day) approached the benchmark (P(HI > 1) = 0.04%). Sensitivity analysis attributed 62% of HI variance to ingestion rate and 24% to inorganic As fraction, identifying dietary behavior as the primary modifiable driver. Stress-testing (2026–2036) showed that lifetime cancer risks remain within the acceptable regulatory corridor (10 −6 to 10 −4 ), though narrowing safety margins under pessimistic trajectories underscore the necessity of basin-scale pollution abatement and speciation-informed dietary guidance.