Asian Basic and Applied Research Journal

The assessment of heavy metals in some selected soils and Manihot esculenta was carried out in Wukari local government area of Taraba state. The main aim of this work was to assess the heavy metals in soils and some selected Manihot esculenta from Wukari. The study also assessed the cancer risk (CR) and hazard quotient (HQ) associated with consuming these analyzed crops. The samples were collected from six different randomly selected site in Wukari Mechanic village, A; Sukundi road, B; Jalingo road, C; Ibi road, D; Kente Road, E; and Rafin kada road, F. The samples were washed, peeled, dried, pulverized and analyzed for heavy metal content using the Atomic Absorption Spectrophotometer. The results revealed that Pb (71 -200.8 mg/kg), Cd (1.8 - 3.1 mg/kg), Zn (50 - 163.30 mg/kg) and Ni (30-56.7 mg/kg) were above permissible limit of (85, 0.8, 50 and 35 mg/kg for Pb, Cd, Zn and Ni respectively by WHO) while Cr (0.2-0.3 mg/kg) and Cu (3.3-20.0 mg/kg) were below the permissible limit of 100 mg/kg and 36.0 mg/kg for Cr and Cu respectively by WHO in the soil samples. Similarly, the heavy metals in the tuber crops also have Pb (7.5 – 13 mg/kg), Cd (0.2 - 1.1 mg/kg), Zn (20 – 30 mg/kg and Ni (10 – 50 mg/kg) above the WHO permissible limit of 2.0, 0.02, 0.6 and 10 mg/kg respectively. Cr (0.1-0.3) was below the permissible limit of 1.30 mg/kg while Cu was not detected for all the Manihot esculenta samples. The risk assessment analysis showed that the highest and lowest hazard quotient values of Pb and Cr are 26.07 and 0.17, respectively. Also, the highest and lowest cancer risk was recorded in Cd (8.6×10^-2) and Cr (2.6 ×10^-4), respectively. The results of this study are expected to gain public awareness that consuming locally produced tuber crops from sites contaminated with heavy metals is at risk of heavy metal toxicity, such as liver damage, neural, and respiratory disorders, among others.