Heavy Metals Speciation and Health Risk Analysis of Arable Farmlands In Ardo-Kola, Bali and Wukari Local Government Areas of Taraba State Nigeria

Background and Objective: Agricultural soil plays a major role in food safety and security. A major problem in most developing nations including Africa is a lack of food safety. The soil environment is a reservoir of nutrients as well as pollutants. This study evaluated heavy metals speciation and health risk analysis of arable farmlands in Bali, Ardo-Kola and Wukari, Local Government Areas of Taraba State, Nigeria. Materials and Methods: Three different soil samples from three Local Government Areas of Taraba State (Bali, Ardo-Kola Wukari) were collected using sterile glass sample collection bottles measured at 5 cm depth. The collected soil samples were freed from unwanted materials such as stone, leaves debris by hand picking and air-dried for one week to remove excess moisture, large soil clouds were also crushed to facilitate the drying. The dried soil samples were crushed in a porcelain mortar with a pestle, the crushed soil sample was sieved through a 2 mm sieve made of stainless steel the sieved soil sample was further pulverized to a fine powder and passed through a 0.5-mm sieve. Heavy metals (Pb, Cd, Cr, Hg and As) concentrations were assayed using Atomic Absorption Spectrophotometry (AAS). Results: The results showed that Chromium had a high concentration with values ranging from 1.40 mg/kg to 2.71 mg/kg. While Lead and Mercury had the lowest concentration of less than 0.03 mg/kg across the studied areas. For ecological risk assessment parameters; target cancer risk, hazard index (HI) estimated daily intake (EDI) were all determined to assess the non-carcinogenic health risk. Ardo-Kola recorded the highest levels of HM, whereas Bali had the lowest. Consumption of crops harvested from the sampled location may pose a serious health challenge; bio-accumulation of toxicants in the soil across the studied areas may pose a health risk due to high concentration of heavy metals which are known to generate free radicals that may lead to oxidative stress and other cellular damages in humans. Conclusion:Although the studied heavy metals were significantly present in all the analyzed soil except lead, their concentration in various soil samples across the studied areas exceeded the permissible levels as recommended by WHO.