Resumen
Clay soil samples used for pottery were collected at a depth of 0-30cm from Ara-Ekiti and Kono-Boue communities in Southern Nigeria between May and November 2020 to evaluate the concentrations of some heavy metals (Fe, Pb, Cu, Zn, Mn, Cd, Cr, and Ni). The concentrations of the heavy metals were analyzed using Atomic Adsorption Spectrometer. The level of the studied heavy metals in the two communities were lower than the DPR background value. The results obtained showed that average concentrations of heavy metals in Ara-Ekiti were, Fe; 3094.73±6.29, Pb; 135.87±0.94, Cu; 17.79±0.14, Zn; 93.30±0.55, Mn; 418.51±0.81, Cd; 6.59±0.04, Cr; 69.10±0.83 and Ni; 76.95±0.11 mg/Kg, while that of Kono-Boue were Fe; 2048.99±35.67, Pb; 195.40±0.52, Cu; 31.04±0.17, Zn; 135.74±0.98, Mn; 135.74±0.98, Cd; 15.44±0.61, Cr; 71.17±1.27 and Ni; 98.66±0.94 mg/Kg. The results revealed also that heavy metals levels were more in Kono-Boue clay soils than Ara-Ekiti clay soils. Pollution assessment indices used for evaluation of the quality of the clay soil from Ara-Ekiti and Kono-Boue were: contamination factor (CF), pollution load index (PLI), contamination degree (CD), modified contamination degree (mCD), potential ecological risk coefficient (Eir), potential ecological risk index (RI), Geo-accumulation index (Igeo) and anthropogenicity. The pollution indices values indicated that the clay soils of the two Nigerian communities were either contaminated or polluted by heavy metals. Although the concentrations obtained were lower than the DPR tolerable limits, yet there should be need for adequate monitoring of the clay products that come from these communities to avoid onward transmission of heavy metals to humans due to dangerous effects they pose to human health.