Industrial Emissions and Toxic Metals Bioaccumulation in Cassava Cultivated around Mfamosing Cement Plant, Akamkpa: A Toxicological Risk Evaluation for Consumers

Abstract

Industrial emissions from cement production are significant sources of environmental contamination, raising concerns about the safety of food crops cultivated near such facilities. This study evaluated the concentrations of toxic metals (lead, cadmium, mercury, arsenic, and chromium) and assessed the associated health risks from consuming edible cassava tissues harvested from areas surrounding the Mfamosing Cement Plant, Nigeria, between June and December 2023. Cassava samples were systematically collected at varying distances from the cement plant and analyzed using an atomic absorption spectrophotometer (Model 6800, Japan) after wet digestion. Health risk assessments were conducted following the US-EPA models, using Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), Hazard Index (HI), Incremental Lifetime Cancer Risk (ILCR), and Cumulative Cancer Risk (CCR). Results showed that the total heavy metal concentrations (mg/kg) were of the ranges: lead (0.07–1.11), cadmium (0.05–0.61), mercury (0.01–0.05), arsenic (0.01–0.05), and chromium (0.01–0.06 mg/kg). The mean concentrations of Pb, Cd, and Hg in cassava tissues exceeded FAO/WHO and EU permissible limits, with EDI values surpassing the Recommended Daily Intake (RDI) and Tolerable Upper Intake Levels (UL). While the individual THQ remained below unity, HI exceeded unity at the site closest to the cement plant, indicating possible non-carcinogenic risks. Notably, the ILCR and CCR values for Pb, Cd, As, and Cr exceeded the regulatory safety thresholds (10⁻⁴), indicating significant carcinogenic risks to consumers. The study concludes that consuming cassava cultivated near the Mfamosing Cement Plant poses both carcinogenic and non-carcinogenic health risks to local communities.