Heavy metal and metalloid contamination significantly threaten the environment and human health. The use of soil environmental assessment indicators is important as they provide valuable information about soil health, quality, and potential risks to ecosystems. The purpose of this investigation is to determine the soil content of Cd, Cu, Fe, Mn, Ni, Pb, Zn, and Pb in an area exposed to various sources of pollution, as well as, assess soil heavy metal contamination using five of single pollution assessments, and three of integrated pollution assessments and compare the obtained data with risk assessment code (RAC). Results showed that concentrations (mg/kg) of Cd (3.32) and nickel (71.26) were above Threshold limits. While Cu, Fe, Mn, Pb and Zn contents, were below their corresponding threshold limits reported by the published threshold limits. Fractionation results showed that the general trend in almost all tested metals, on average, the order was residual (50.11 %)> followed by reducible (21.67%), carbonate (13.33%), organic (9.29%), and an exchangeable fraction (5.60%), however, the quantities varied. The calculated pollution assessments revealed that ; (CF) values showed that the soil was very highly polluted with Cd (8.1), moderately polluted with Cu (1.3), Mn (1.04), Ni (2.46), Pb (1.35), and Zn (1.05), while low polluted with Fe (0.36); Er index values indicated that the soil was considered low potential ecological risk, except for Cd which was categorized as highly potential ecological risk (242.93); EF index indicated that Cd and Ni were categorized as significant enrichment (22.74, and 6.9, respectively), while, (Mn, Pb, and Zn) were moderately enrichment, and Fe was minimal enrichment; Igeo index values revealed that only cd was categorized as moderately contaminated (2.43), Ni was slightly contaminated (0.71), while the rest of the metals were classified as uncontaminated (minus values); PIT index revealed that Cd categorized from (moderately to low polluted), while Ni was categorized low polluted, while (Cu, Fe, Pb, Mn, and Zn) were categorized as unpolluted. Also, the results of the integrated soil assessment indices were calculated; the results of the PLI index (1.45) revealed that the soil was considered polluted soil, the PERI index considered the soil moderate ecological risk, and the NCPI index classified the soil as slightly polluted. RAC indicated the soil high risk with Cd (30.04), and medium risk with (Cu (21.9), Mn (19.96), Ni (23.72), Pb (13.67), and Zn (16.14), while for Fe, the soil was lies in the low-risk category. Taking the RAC index as a reference result, the data revealed that among the tested single assessment indices (CF, EF) were consistent with RAC values, Also, the integrated indices (PLI, and PERI) indices, as well as NCPI when using threshold data of CSQG only were consistent with RAC data. So, it is clear that the indices that rely solely on the total or threshold level of pollutants may often be inaccurate and show several disagreements and make it challenging to compare soil quality data internationally or even locally, while soil evaluation using indices that depend on the speciation of pollutants in soil is more realistic.
Keywords : Soil Heavy Metals, fractionation of soil heavy metals, risk assessment code (RAC), Soil pollution indices,
Received:7/2/2024 12:00:00 AM; Accepted: 8/15/2024 12:00:00 AM