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Thirty-nine paired soil samples belonging to Inceptisols, irrigated with wastewater and well water, were examined to monitor the combination of clay mineralogy, physicochemical properties, and trace metals (Zn, Cu, Cd, and Pb) following longterm wastewater irrigation. Results of XRD analysis indicated that the quantity of clay minerals did not change by long-term wastewater irrigation although some modifications in smectite were occurred in Fluvaquentic Endoaquepts compared to control (well water-irrigated soil). Irrigation with wastewater was resulted in an increase in clay content from 3 to 17%, EC from 90 to 160%, organic carbon from 13 to 44%, and CEC from 10 to 13%. In this context, improvement in total N was as 80-110%, available P as 270-330%, and available K as 5-50% as compared to the control soil. Irrigation with wastewater was led to a significant enrichment in both EDTA-extractable and total metals of Zn, Cu, Cd, Pb, mainly as result of the combination of their addition through wastewater along with interaction between the used wastewater and its receiving soils. In the light of this, wastewater irrigation system showed the relative enrichment (RE) for total-Zn, Cu, Cd, and Pb as 3.6-6.8, 2.8-4.9, 4.4-5.7, and 1.8-2.3, respectively. Fine particle-size fraction (\0.002 mm), organic matter, and calcium carbonates were appeared as the main agents in retaining the total trace metals as reflected in significant positive correlation among the physicochemical properties and the examined metals. Degree of contamination (C d ) for the four analyzed metals was in the range of 3-5. Based on C d values, the wastewaterirrigated soils were classified as moderate degree of contamination (2 B C d \ 4) to high degree of contamination (4 B C d \ 8). Fluvaquentic Endoaquepts highlighted to be a major contributor of the load and contamination rate of trace metals regarding to geoaccumulation index, contamination factor, and Degree of contamination.

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The contamination of urban soils with heavy elements due to the rapid development of urbanization and urban services has become a major environmental and human health challenge. This study provides insight into the urbanization controls on combined pollution severity and health risk potential of heavy metals in corn-cultivated urban versus non-urban soils. A multifaceted assessment was conducted using enrichment factor (EF), ecological risk (ER), bioconcentration factor (BCF), transmission factor (TF), hazard index (HI), and carcinogenic risk (CR). The results indicate a significant increase in the concentration of all metals in urban farmlands. When compared to the non-urban soils, EF implies a significant increase of all metals in the urban soil, downgrading this index from minimal enrichment (EF < 2) in the control soils to moderate enrichment (2 ≤ EF < 5) in the urban soils. Likewise, the average ER value showed an increase in the urban soils than in the control soils in the order of Fluvisols (66.6%) > Regosols (66.1%) > Cambisols (59.8%) > Calcisols (47%). The BCF and TF values for different elements decreased in the order of Cd (0.41–0.92) > Cu (0.1–0.23) > Zn (0.1–0.18) > Ni (0.01–0.03) > Pb (0.005–0.011) and Zn (0.75–0.94) > Cu (0.72–0.85) > Pb (0.09–0.63) > Cd (0.17–0.22) > Ni (0.01–0.21), respectively, which indicates that certain metals were not mobilized to the extent that they had been accumulated in the plant roots. The total carcinogenic risk was ranged from 5.88E−05 to 1.17E−04 for children and from 1.17E−04 to 2.30E−04 for adults, which implies a greater associated health risk for children.

The concentration and dynamic of soil trace metals in natural ecosystems, in particularly, is dependent on the lithology of parent rock as well as topography and geopedological processes. To ascertain more knowledge for this dependency, soils on three parent rocks involving peridotite, pegmatite, and dolerite in two contrasting topography aspects were investigated. The total values of Fe, Mn, Zn, Cu, and Ni were determined and compared for different soil pedons. ) [ dolerite (28 mg kg -1 ), respectively. For most of the studied pedons, profile metals distribution differed among the soils: The values of Fe, Cu, and Ni were enriched in the cambic horizons mainly as result of release, mobilization, and redistribution of the studied metals during geopedological processes, whereas those of Zn and Mn were concentrated in the surface horizons. Probably due to greater weathering rate of trace metal-bearing rocks on north-facing slope, the content of the trace metals along with the geoaccumulation index (I geo ) and the degree of soil contamination (C d ) were higher than on south-facing slope. Based on assessment of soil pollution indices, the soils were categorized as unpolluted [I geo B 0 (class 0)], unpolluted to moderately polluted levels [0 \ I geo \ 1 (class 1)], and very low [C d \ 1.5 (class 0)] to low degree of contamination [1.5 \ C d \ 2 (class 1)].