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

Abstract

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.