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

iv. Human Health Risk Index (HHRI) The human health risk index is the proportion of DAE and an oral recommended allowance(ORA) employing the subsequent equation: = (USEPA-IRIS, 2002; Ogunwale et al., 2021) ……………………….eqn (iv) Where DAE is the daily allowance of elements and ORA is the oral recommended allowances. The ORA is the highest amount of acomponent, in milligrams per day, that the body can be vulnerable to the outside of yielding a hazardous outcome during a lifespan. Oral recommended allowances were 3.00E-04, 1.00E-03, 4.00E-02, 3.00E-01, 4.00E-03, and 3.00E-01 mg/kg/day for As, Cd, Cu, Mn, Pb, and Zn, respectively (USEPA- IRIS, 2002). An HHRI<1 implies that the vulnerable consumers are said to be in safety (Ogunwale et al., 2021). When uniting Equation (iii), and (iv) along with HHRI=1, the maximum limit for the amount of food that can securely be eaten on an everyday basis is expressed as: = ℎ × × …………………….…………………..eqn (v) v. Target Hazard Quotient (THQ) Technique The potential health risks of heavy element allowance through staple foodstuffs were analyzed- depending on the target hazard quotient (THQ) method, which was indicated thoroughly using the United States Environmental Protection Agency (USEPA-IRIS, 2002). The THQ is considering through the subsequent equation: = × × × × × × 0.001 ……….eqn (vi) Where EF r is the exposure frequency (350 days/year); ET is the exposure time (55.12 years, corresponding to the mean lifespan of the Nigerian population); F l is the food ingestion rate (staple foodstuff (sweet cassava, maize, plantain, and white yam) allowance analyzes for adults is 800.0 g/person/day) was adopted for this work (Balkhair and Ashraf, 2016); EC is the element content in the consumable portions of staple foods (mg/kg); ORA is the oral recommended allowance (As, Cd, Cu, Mn, Pb, and Znvalues were 3.00E-04, 1.00E-03, 4.00E-02, 3.00E-01, 3.50E-03, and 3.00E-01 mg/kg/day, respectively) (USEPA-IRIS, 2002); BS is the mean weight of the body size (60 kg for adults) (USEPA-IRIS, 2002); and MD is the mean exposure duration for non-carcinogens (365 days year− 1 × number of exposure years, supposing 55.12 years in this work). If the THQ value is above 1, the condition is likely to cause significant harmful effects. The total diet THQ (TDTHQ) of heavy elements for staple foods is stated explicitly using the following equation (Storelli, 2008;Zhou et al., 2016). = ∑ ( ) =1 …………..…eqn (vii) f) Quality Control Adopted Utilized With the intention of determining the effectiveness of the HNO 3 – HClO 4 method of sample digestion, a recovery test was done by spiking 1 g of twenty (20) and ten (10) different soil, cassava, maize, plantain, and yam samples each with 1 cm 3 of standard solutions of the elements As, Cd, Cu, Mn, Pb, and Zn. Recovery test presented % recoveries > 80%. Element contents in functioning standards and digested samples were performed with FAAS (Alpha Star Model 4, Chem- Tech Analytical) at the Centre for Energy Research and Development (CERD) of the Obafemi Awolowo University, Ile-Ife, Nigeria. Instrumental conditions are as stated earlier (Ogunwale et al., 2021). Blanks were also prepared to estimate the input of reagents to element contents. III. R esults a) Physicochemical and Heavy Elements Attributes of the Farmland Soils The soil attributes (Table2) were assessed in relation to the Ogunwale et al. (2021) guidelines. The investigated variables comprised pH, electrical conductivity (EC), total organic carbon (TOC), and total organic matter (TOM). Supposing the mean value of carbon in soil organic matter (˜58% w/w), an adjustment factor of 1.72 was applied to determine the percentage of organic matter (OM) from the value of organic carbon (Ogunwale et al., 2021). Table 3 demonstrates the levels of As, Cd, Cu, Mn, Pb, and Zn (mg/kg) in soils present from farmed and non-farmed (control) sites in the research area for both seasons. The mean values of all heavy elements for wet and dry seasons varied from ND-743. 44 mg/kg and ND-806.73 mg/kg, respectively. Arsenic in both seasons varied from 3.27-7.38 mg/kg and Mn ranged from 236.10-806.73 mg/kg in farmed soils while their values were 0.04 and 0.07 mg/kg and 5.12 and 8.95 mg/kg in non-farmed soils, respectively. The levels of most heavy elements in wet and dry seasonswere0.06- 0.46, 9.08-23.27, 3.85-13.16, and 16.66-36.12mg/kg for Cd, Cu, Pb, and Zn, respectively while the values for Cropland Bioaccumulation Risks of Potentially Toxic Elements in Soil of Some Designated Foodstuffs Cultivated in Odu’a Farm Establishment, Aawe, Oyo State, Nigeria 1 Year 2023 9 © 2023 Global Journals Global Journal of Science Frontier Research Volume XXIII Issue ersion I VI ( )D