Assessment of Heavy Metal Contaminants in Selected Soil and Yam of Some Areas of Keffi LGA Nasarawa State, Nigeria

Abstract

This research aims to investigate the impact of heavy metal contaminants in soil and yam samples in 
selected areas of Keffi LGA Nasarawa State, Nigeria. The concentrations of various heavy metals, including 
manganese (Mn), copper (Cu), cobalt (Co), cadmium (Cd), zinc (Zn), and lead (Pb), were analyzed in both 
soil and yam samples, using an AA320N-Atomic Absorption Spectrophotometer equipped with air- 
acetylene burner. Additionally, soil properties such as pH, soil organic matter percentage, and soil 
conductivity were examined. All samples have no detectable levels of Pb. Agwan Turu Mada had the 
highest levels of Mn (490.75 mg/kg) and Cu (30.01 mg/kg), while Maraba Mesori had the highest levels of 
Co (7.56 mg/kg) and Zn (87.71 mg/kg). The mean and standard deviation for the levels of heavy metals in 
the yam samples were Mn-8.71 (+/-2.59), Cu-1.63 (+/-0.78), Co-4.97 (+/-3.87), Cd-0.74 (+/-0.83), Zn-0.93 
(+/-1.08), and Pb-0 (+/-0). Keffi had the highest levels of Mn (12.29 mg/kg) and Zn (1.13 mg/kg), while 
Maraba Mesori had the highest levels of Co (9.43 mg/kg) and Cd (1.01 mg/kg). Agwan Rimi Mada had the 
lowest levels of all heavy metals except Cd (1.79 mg/kg). These values were within the acceptable limits. 
The pH values ranged from 6.56 to 7.45, indicating slightly acidic to neutral conditions, which are suitable 
for most crops. The soil organic matter percentages ranged from 4.00% to 5.75%, falling within the 
desirable range for agricultural soils. Soil conductivity values ranged from 72.02 µS/cm to 202.60 µS/cm, 
suggesting varying levels of salinity and nutrient availability. However, continuous monitoring and proper 
soil management practices are crucial to mitigate potential risks associated with heavy metal contamination 
and ensure long-term agricultural sustainability.