Heavy Metal Contamination and Health Risk Assessment of Smoked-Dried Fish Sold in Eke-Awka Market, Anambra State, Nigeria

This study investigated the concentrations of selected heavy metals—zinc (Zn), lead (Pb), cadmium (Cd), copper (Cu), and arsenic (As)—in four smoked-dried fish species widely consumed in southeastern Nigeria: catfish (Clarias gariepinus), mackerel (Scomber scombrus), bonga fish (Ethmalosa fimbriata), and asa fish (Gymnarchus niloticus). Samples were obtained from Eke-Awka Market and analyzed using Atomic Absorption Spectrophotometry. Results, expressed in mg/kg dry weight, revealed statistically significant interspecies variations (p < 0.05). G. niloticus exhibited the highest concentrations of Zn (5.47 ± 0.71), Cd (0.25 ± 0.01), and As (0.04 ± 0.02), while S. scombrus contained the highest Pb level (0.16 ± 0.01). Conversely, C. gariepinus recorded the highest Cu concentration (0.74 ± 0.05). Although all concentrations were below the permissible limits set by the World Health Organization (WHO) and Federal Ministry of Environment (FME), the health risk assessment revealed that the target hazard quotients (THQs) and the cumulative hazard index (HI = 0.362) were below 1, indicating no significant non-carcinogenic risk. However, the lifetime cancer risk (LCR) for cadmium (1.2 × 10⁻³) exceeded the acceptable USEPA threshold, suggesting a potential long-term carcinogenic concern from continuous dietary exposure. These findings indicate that while the smoked-dried fish are generally safe for consumption in the short term, routine monitoring is essential, with particular attention to G. niloticus, which demonstrated higher accumulation of several metals. Improved hygienic smoking practices and strengthened regulatory oversight are recommended to safeguard public health.