The potential ecological risk of soil trace metals following over five decades of agronomical practices in a semi-arid environment |
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Authors: | Salar Rezapour P. Kouhinezhad A. Samadi |
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Affiliation: | Soil Science Department, Urmia University, Urmia, I.R. Iran |
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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?
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Keywords: | Soil ecological risk trace metal total form DTPA-extractable fraction |
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