Assessment of Heavy Metals Concentration in Commercial and Domestic Cassava Flour in Ijebu-Igbo, Ogun State Nigeria

In Nigeria, where traditional processing methods like roadside drying are common, heavy metal contamination of staple foods poses a serious concern to public health. The degree of heavy metal contamination in cassava fl our (Manihot esculenta Crantz) processed and marketed in Ijebu Igbo, Ogun State was evaluated in this study. Samples were collected from three sources; a commercial outlet at Ijebu Igbo Central market, a roadside drying site along the Ibadan-Ijebu Ode road, and a controlled self-dried batch from the researcher resident in Ijebu Igbo. Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) was used to measure the amounts of manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), chromium (Cr), and selenium (Se) concentration in all the three samples and compared with WHO/FAO standards. Results revealed that the market-bought sample from Ijebu Igbo Central market contained Pb (2.2 mg/kg) and Cr (3.3 mg/kg) exceeding WHO/FAO permissible limits. The roadside-dried sample from Ibadan-Ijebu Ode road had the highest levels of Fe (21.7 mg/kg) and Cr (0 mg/kg), also exceeding WHO/FAO permissible limits. In contrast, the self-dried sample showed no detectable Cd, or Cr, indicating it was the safest. However, all samples had Selenium levels (1.3–3.2 mg/kg) above the WHO/FAO permissible limit. The fi ndings highlight the elevated health risks associated with cassava fl our from market and roadside sources due to environmental contamination during processing and drying. The study recommends the adoption of controlled drying practices, enhanced market processing standards, and stricter regulatory enforcement to ensure the safety of this widely consumed staple food.