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The potential ecological risk of soil trace metals following over five decades of agronomical practices in a semi-arid environment

Author:
Rezapour, Salar, Kouhinezhad, P., Samadi, A.
Source:
Chemistry in ecology 2018 v.34 no.1 pp. 70-85
ISSN:
1029-0370
Subject:
Calcisols, Cambisols, Chernozems, Vertisols, cadmium, copper, manganese, pesticides, phosphorus fertilizers, risk, semiarid zones, soil profiles, zinc
Abstract:
The concentration and potential ecological risk of Mn, Zn, Cu, and Cd in the surface soils (0–30 cm) belonging to 12 soil profiles and 4 soil types (Vertisols, Chernozems, Calcisols, and Cambisols) from the cultivated soils and the corresponding uncultivated soils were investigated. Long-term cultivation caused a considerable build-up diethylene-triamine pentaacetic acid (DTPA)-extractable Mn (7–55%), and Cd (12–31%) as well as the total form of Zn (3–14%), Cu (8–25%), and Cd (33–78%) in all soil types. Following long-time cropping, total Zn (mean = 73 mg kg⁻¹), Cu (mean = 33 mg kg⁻¹), and Cd (mean = 3.14 mg kg⁻¹) and DTPA Zn (mean = 1.2 mg kg⁻¹) and Cu (mean = 2.44 mg kg⁻¹) were below their maximum allowable limits. However, the average amount of DTPA Cd in the tilled soils (min = 0.4, max = 0.75, mean = 0.55 mg kg⁻¹) was above its maximum permissible limit mainly due to the over application of phosphate fertilisers and the pesticides. Considering the potential ecological risk (RI) assessment of the cultivated soils (min = 44, max = 70, mean = 54), the soil types were categorised as low (RI ≤ 50) to moderate (50 < RI ≤ 100) potential ecological risk.
Agid:
5953123