Risk evaluation of the concentration of heavy metals in seeds, cereals, and legumes sold in Nasarawa major market, Nigeria

Abstract

Heavy metal contamination in food crops can pose non carcinogenic and carcinogenic health risks, particularly to children. This study assessed selected metals in black eye bean, soya bean, millet, sorghum, sesame, and locust bean. The metals arsenic, nickel, aluminium, copper, magnesium, potassium, calcium, and sodium were evaluated using inductively coupled plasma optical emission spectrometry, and exposure was estimated using estimated daily intake, hazard quotient, hazard index, and target carcinogenic risk for adults and children. The essential macro elements were quantified and reported for nutritional context, while health risks for the potentially toxic metals were estimated using the United States Environmental Protection Agency framework for ingestion and dermal exposure pathways. The hazard quotient for arsenic, nickel, aluminium, and copper were below one for adults, but children showed elevated values for arsenic and copper. Hazard index values for potentially toxic metals were below one for both adults and children, indicating no significant non carcinogenic risk, and dermal exposure was negligible. However, the findings indicate that although non carcinogenic hazard from these crops remains within acceptable limits, chronic dietary exposure to arsenic and nickel poses a carcinogenic risk exceeding the recognised acceptable threshold of one in ten thousand across the entire study population, with sesame and sorghum identified as priority crops. Correlation, principal component analysis, and cluster analysis indicated meaningful associations among the metals, with several elements grouping in ways that suggest related behaviour or common accumulation pathways.