Assessment of the Bioaccumulation of Heavy Metals in Soil and Selected Vegetables in Barkin Ladi and Riyom Areas of Plateau State, Nigeria

The intake of heavy metals through contaminated food crops has raised concerns about potential carcinogenic and non-carcinogenic health impacts on humans. This study assessed levels of heavy metals in vegetables (lettuce, green beans, carrots, eggplant, cabbage, and spinach) and soil obtained from Barkin Ladi and Riyom Areas of Plateau State, along with their bioaccumulation. A total of six vegetables and six soil samples were taken from farms in each of these areas, prepared and digested using aqua regia, and the supernatant was analyzed using AAS for heavy metals (Pb, Zn, Cr, Co, Cd, Mn, and Cu). The concentration of these metals in vegetables in Barkin Ladi ranged from Pb (0.0019 – 0.0165), Zn (0.0783 – 2.7462), Cr (0.0814 – 0.2994), Co (0.0027 – 0.1165), Cd (0.0012 – 0.0170), Mn (0.0280 – 1.1132), and Cu (0.1851 – 1.4199) in mg/kg respectively, while in Riyom the values varied from Pb (0.0013 – 0.0145), Zn (0.0763 – 2.7432), Cr (0.0804 – 0.2944), Co (0.0017 – 0.1135), Cd (0.0010 – 0.0150), Mn (0.0230 – 1.1102), and Cu (0.1751 – 1.2199) in mg/kg correspondingly. The average concentration of heavy metals Pb, Zn, Cr, Co, Cd, Mn, and Cu in soil from Barkin Ladi and Riyom were 0.0138, 0.2495, 0.0722, 0.4646, 0.0577, 3.4897, 0.9007 and 0.0124, 0.2465, 0.0690, 0.4523, 0.0555, 3.4755, 0.8973 mg/kg respectively. The bioaccumulation factor for Pb in both study areas is less than 1.00 except for eggplant, which has values of 2.895 and 3.919 in Barkin Ladi and Riyom respectively, raising concern. The accumulation of Pb can be harmful to human health due to long-term consumption of eggplant in these areas. Other metals with bioaccumulation values greater than 1.00 are not significantly toxic to humans. However, constant monitoring of these metals in vegetables within these areas is recommended to prevent accumulation from long-term consumption, which could have negative impacts on human health.