Trace metal contamination and health risk assessment of edible land snails (Achatina achatina) in Yenagoa Metropolis, Nigeria

Background Trace metal contamination of edible land snails is an emerging public health concern due to their strong bioaccumulation capacity in polluted environments. This study assessed trace metal concentrations, dietary exposure, and associated health risks of Achatina achatina consumed in Yenagoa Metropolis, Nigeria, to evaluate food safety and ecological implications. Methods Sixty A. achatina samples were collected from 12 locations across Yenagoa Metropolis. Concentrations of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) were quantified using Atomic Absorption Spectrophotometry. Spatial patterns and potential contamination sources were explored using descriptive statistics, Pearson correlation, Principal Component Analysis (PCA), and hierarchical cluster analysis. Human health risks were evaluated through Estimated Daily Intake (EDI), Hazard Quotient (HQ), Hazard Index (HI), and carcinogenic risk assessment. Results Trace metal concentrations (mg/kg dry weight) ranged as follows: Cd (1.274–6.839), Co (0.928–7.004), Cr (0.066–3.102), Cu (28.871–64.589), Fe (121.675–507.840), Mn (65.516–146.889), Ni (0.537–7.410), Pb (2.456–8.881), and Zn (68.759–102.069), with significant spatial variability ( p < 0.05). Cd, Pb, and Ni exceeded permissible limits at several sites, reflecting anthropogenic inputs such as vehicular emissions, waste combustion, and crude oil–related activities. PCA and cluster analysis analyses revealed strong associations among Co, Cr, Fe, Ni, and Pb, suggesting common pollution sources. The HI exceeded unity at all locations, indicating potential non-carcinogenic risk, while carcinogenic risks for Cd, Cr, Ni, and total lifetime cancer risk surpassed USEPA acceptable thresholds. Conclusion The findings demonstrate that consumption of A. achatina from Yenagoa may pose significant non-carcinogenic and carcinogenic health risks. Continuous monitoring, improved pollution control, and public awareness are essential to safeguard consumer health.