Agriculture remains the primary source of livelihood among the Ogoni people of the Niger Delta, with vegetables playing a vital role in food security and nutrition. High concentrations of heavy metals in soil and crops can have significant consequences for both the environment and human health. The study aimed to evaluate the concentrations of heavy metals in agricultural soil and Telfairia occidentalis (fluted pumpkin leaf) samples, as well as the associated risk. Soil and T. occidentalis samples were collected from five farmlands (K1–K5) in Kaa, a village in the Ogoni region of Rivers States, Niger-Delta, and analysed for specific heavy metals using Atomic Absorption Spectrophotometer following standard digestion procedures. The results of the analysis showed that the soil samples had different concentrations of heavy metals within the following ranges: Fe (2.053-5.307 mg/kg), Mn (1.843-2.873 mg/kg), Zn (3.380-4.433 mg/kg), Cd (0.070-0.850 mg/kg), and Ni (0.320-0.513 mg/kg). No traces of Co were found in any of the samples. In T. occidentalis samples, the amounts of Fe ranged from 1.787 to 4.167mg/kg, Zn ranged from 0.010 to 2.330mg/kg, Mn ranged from 0.826 to 1.053mg/kg, Cd ranged from 0.063 to 0.723mg/kg, and Ni ranged from 0.020 to 0.477mg/kg. Co was absent in all of the samples. The heavy metals analysis revealed that the concentrations of these metals in the soil were found to be within the maximum levels allowed for agricultural soils according to standard criteria. Therefore, the soil in the research region is considered to be of good quality and safe. The metal accumulation patterns reported in T. occidentalis were generally minimal, except for Cd. The average transfer factor (TF) of heavy metals in T. occidentalis throughout the site indicates that Cd had the greatest mean TF (0.86). The study found that the levels of Cd, Ni, Fe, Zn, and Co in the soil and T. occidentalis in the study sites were moderately contaminated, with a contamination factor (CF) ranging from 1 to 3. The Pollution Load Index (PLI) for all the heavy metals (Cd, Mn, Ni, Fe, and Zn) suggests that the contamination levels are rather low. The concentration of Cd in the soil was found to be quite high, measuring 31850.85. The highest ErF (51725.42) was observed in T. occidentalis and soil (38799.91) at sites K5 and K1. These places show an indication of an increase in pollution potential. The Incremental Lifetime Cancer Risk (ILCR) associated with the consumption of T. occidentalis may provide a cancer risk, since the calculated values surpass the maximum threshold of 1×10-4. Based on the results, it can be concluded that consuming T. occidentalis grown in the examined habitat poses no significant danger.. Continuous monitoring of soil quality and regulation of agrochemical use are therefore recommended to safeguard environmental quality and public health.
Nukebabari et al. (Wed,) studied this question.