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Spatial Distribution and Mapping of Heavy Metals in Agricultural Soils of the Sfafaa region (Gharb, Morocco)

2019; Elsevier BV; Volume: 13; Linguagem: Inglês

10.1016/j.matpr.2019.04.046

2214-7853

N. El Khodrani, S. Omrania, Abdelmjid Zouahri, Ahmed Douaik, Hamza Iaaich, Ahmed Yahyaoui, Mohammed Fekhaoui,

Geochemistry and Geologic Mapping

Our study has the purpose of mapping the vulnerability of the soils of the Sfafaa region by the contamination of heavy metals through their monitoring. A campaign of soil sampling and analyzes in the laboratory has been realised. The approach followed is the spatial analysis using Geographic Information System (GIS). The data have been spatialized through the GIS in order to establish the relationship between the levels of contamination observed for each species and their spatial distribution. The total concentrations of heavy metals were assessed for samples from seventeen sites representative of the agricultural lands, selected along the Beht River, over a period from March to June of 2013 and 2014. Concentrations of eight elements were determined: Mn, Cd, Cr, Cu, Ni, Pb, Zn and Fe. The results show that Ni, Cr, and Cd present high concentrations in plots irrigated by groundwater. Cr concentration is the most important (319.7 ppm), exceeding the standard for a normal soil (100 ppm) while the average content of Zn is 89.8 ppm, below the standards for a normal soil (200 ppm). In general, the results showed a metal contamination that exceeds the standards for Ni (62.7 mg/kg in average and values ranging from 21.6 to 102.4 mg/kg), Cd (1.9 mg/kg in average and values ranging from 1.3 to 3.2 mg/kg), and Cr (274.8 mg/kg in average and values ranging from 200.7 to 327.4 mg/kg), due to the overuse of fertilizers. These results confirm the impact of the agriculture intensification on the quality of the soils in the Gharb region.