LEAD AND CADMIUM LEVELS IN SMOKED AND OVEN DRIED Heterotis niloticus AND Protopterus annectens FROM KASUWAR JANBULO, JIGAWA STATE, NIGERIA

Fish is an important and affordable source of animal protein; however, contamination by heavy metals poses significant public health concerns due to their persistence and bioaccumulative nature. This study assessed lead (Pb) and cadmium (Cd) concentrations in smoked and oven-dried Heterotis niloticus and Protopterus annectens obtained from Kasuwar Janbulo Market, Hadejia, Nigeria. A completely randomized design (CRD) was employed with four treatments: smoked Protopterus annectens (A), smoked Heterotis niloticus (B), oven-dried Protopterus annectens (C), and oven-dried Heterotis niloticus (D). A total of seventy-two (72) fish samples were collected monthly over a six-month period (February–July) using a systematic sampling design. Samples were prepared by acid digestion and analyzed for Pb and Cd using Atomic Absorption Spectrophotometry (AAS). Data were analyzed using multivariate analysis of variance (MANOVA) to determine significant differences among treatments. The results showed that Pb concentrations ranged from 0.325 to 0.531 mg/kg, while Cd concentrations ranged from 0.020 to 0.029 mg/kg. Cd levels were within the permissible limit of 0.05 mg/kg set by the World Health Organization and Food and Agriculture Organization. However, Pb concentrations in several samples exceeded the permissible limit of 0.30 mg/kg. Significant variations (p < 0.05) in Pb concentrations were observed among treatments, whereas Cd showed no significant differences (p > 0.05). The findings indicate potential health risks associated with Pb contamination in the fish samples, highlighting the influence of processing methods and environmental exposure on heavy metal accumulation.