Global Journal of Science Frontier Research, D: Agriculture and Veterinary, Volume 23 Issue 1

unfarmed soil were ND, 0.06 and 0.18, 0.03 and 0.07 and 1.64 and 1.96, 6.765, 5.635, and 0.875mg/kg for Cd, Cu, Pb and Zn, respectively. Table 4presents the heavy elementcontents in the assigned food crops (cassava, maize, plantain, and yam) in the area under study. The mean values in cassava for both seasons varied from 0.03-12.24 mg/kg; maize ranged from 0.04-17.38 mg/kg; plantain varied from 0.05-26.14 mg/kg and yam varied from 0.02- 15.43 mg/kg, respectively with an overall mean of 2.00 and 3.08 mg/kg; 0.04 and 0.05 mg/kg; 0.14 and 0.24 mg/kg; 14.89 and 17.80 mg/kg; 0.07 and 0.15 mg/kg and 7.35 and 8.60 mg/kg, respectively for As, Cd, Cu, Mn, Pb, and Zn. The element BF in staple crops is used to express the quantity of bioaccumulation of a compound in a signified biotic complex. Table 5 reveals the BF values of heavy elements in food crops farmed in the research site while Table 6 presents the heavy element pollution load index of features across the sampling points for both seasons. To determine the human health risk per pollutant, it is significant to estimate the level of exposure by finding the routes of contact with target living things. There are numerous likely pathways of contact with humans, but among them, the trophic status is the mostcritical pathway. In our analysis, the mereal lowance path available for As, Cd, Cu, Mn, Pb, and Zn was adopted to staple food allowance. The DAE values were estimated counted on the mean staple food allowance for adults (Table 7) and related to the recommended daily allowances (USEPA- IRIS, 2002). The results for estimating the mean DAE, HHRI, DFA, THQ,TDTHQ, and TTHQ from the heavy element-polluted staple foodstuff crop are presented in Tables 7-10. The results indicated that the DAE and HHRI values were low in the staple food crops while DFA, THQ, and TDTHQ values were high in the staple foodstuff crops. The mean DAE of the staple food crop for both seasons varied from 2.074E-03 to 4.43E-03, 2.267E-05 to 6.800E-05, 6.800E-05 to 4.873E- 04,1.167E-02 to 2.963E-02, 4.533E-05 to 2.607E-04, and 3.094E-03 to 1.365E-02 mg kg −1 person −1 d −1 for As, Cd, Cu, Mn, Pb, and Zn, respectively (Table 7). Likewise, in staple food crops, the mean HHRI values in wet and dry seasons for As, Cd, Cu, Mn, Pb, and Zn ranged from 6.91E-01 to 1.48E+00, 2.27E-02 to 6.80E-02, 1.70E-03 to 1.22E-02, 3.89E-02 to 9.88E-02, 1.30E-02 to 7.45E-02, and 1.03E-02 to 4.55E-02mg kg −1 person −1 d −1 , respectively (Table 8). Equally, the mean DFA of the staple food crops that can be securely eaten on an everyday basis for both seasons varied from 0.542 to 1.157, 11.765 to 35.294, 65.663 to 470.588, 8.101 to 20.560, 10.742 to 61.765, and 17.588 to 77.569, correspondingly (Table 9). Furthermore, in staple food crops, the mean THQ values in wet and dry seasons for As, Cd, Cu, Mn, Pb, and Zn ranged from 7.799 to 16.664, 0.256 to 0.767, 0.019 to 0.137, 0.439 to 1.114, 0.015 to 0.084, and 0.116 to 0.513, respectively (Table 10) while the mean TDTHQ values of the staple food crops for both seasons varied from 34.093 and 52.420, 1.790 and 2.301, 0.173 and 0.311, 2.539 and 3.035, 0.095 and 0.215 and 1.252 and 1.466, respectively for As, Cd, Cu, Mn, Pb, and Zn (Table 10). IV. D iscussion a) Fertility Variables of the Soils The pH is one of the variables governing the bioavailability and the movement of heavy elements in the soil in line with (Ogunwale et al., 2021), heavy element mobility decreases with increasing soil pH owing to the evolution of hydroxides, carbonates, or the formation of insoluble organic molecules. In this analysis, it was revealed that the heavy element contents were rise-considerably with a decrement in the pH. The soil EC also varied considerably with season. On the contrary, (FAO/WHO, 2011) categorized the EC of the grounds as: nonsaline < 2; moderately salty 2–8; very salty 8–16, and potentially salty > 16. From the results of the analysis, the EC is categorized as moderately salty. The EC of the soil samples indicated that all croplands caused no salinity issue (EC < 200 µS cm −1 ). The degree of heavy elements mobilized in the soil ecosystem is influenced by pH, attributes of the elements, redox conditions, soil chemistry, organic matter level, and the like soil qualities (Ogunwale et al., 2021). Heavy elements are naturally more mobile at pH < 7 than at pH > 7. The pH of the soils from the farmland site in both seasons varied from 6.37 to 7.40. As a result, these pH values depict that the ecosystem is slightly acidic to neutral, which is suit able for crop land uses because crops are available to uptake and mildly concentrate heavy elements from polluted soils in their consumable portions (Ogunwale et al., 2021). The levels of organic carbon and organic matter in the soil sample increased considerably with the season. The OC is also elevated with a rising water table (Ogunwale et al., 2021). This finding may be of great ecological interest because it was demonstrated that elevated levels of rain-supplied soil during the study periods elevated the quantities of the OC, which impacts the dissolution and readily available of heavy elements. b) Soils Pollution In all respects, the mean contents of heavy elements in farmland soils from farmed areas were higher than those obtained in soils from the unfarmed areas (Table 3).The contents of heavy elements revealed spatiotemporal differences, which may be owing to the variation in the rich element sources and the degree of heavy elements in the soil. There was an overall resemblance in the pattern of predominance element levels in grounds from both seasons diminishing in the Cropland Bioaccumulation Risks of Potentially Toxic Elements in Soil of Some Designated Foodstuffs Cultivated in Odu’a Farm Establishment, Aawe, Oyo State, Nigeria © 2023 Global Journals 1 Year 2023 10 Global Journal of Science Frontier Research Volume XXIII Issue ersion I VI ( )D