Mapping Potential Toxic Elements in Agricultural and Natural Soils of the Piedemonte Llanero in Colombia

Abstract

[EN] The accumulation of potential toxic elements (PTEs) in soils is usually conditioned by parental material or anthropogenic sources. To achieve correct land management and land degradation neutrality, it is necessary to spatially detect them. However, there are several areas over the world with high concentrations of PTE but without efficient maps and tools to correctly find solutions and apply control measures. The current study attempts to identify the concentrations, sources, and spatial distributions of the main PTEs such as As, Cd, Cr, Cu, Ni, Pb, and Zn in a non-explored area combining fieldwork and geostatistical analysis. In order to accomplish this goal, a total of 90 soil samples were collected in agricultural and natural areas in the Piedemonte Llanero, Colombia. The chemical analysis was conducted by acid digestion and determined through ICP-OES. Then, ordinary kriging was applied to spatially analyze the most vulnerable areas. Our results demonstrated the effectiveness of these techniques and it is noted that the agricultural areas presented the highest concentrations and represented the potential source of PTEs. On the other hand, the natural areas presented the following concentrations of PTEs Cr (17.10 mg/kg), As (2.92 mg/kg), Cu (7.57 mg/kg), Ni (8.63 mg/kg), Cd (0.17 mg/kg), Pb (8.80 mg/kg), and Zn (27.57 mg/kg) lower than agricultural soils. This information was a key first step to be presented to the policymakers and stakeholders to organize soil sustainable management plans for the Piedemonte Llanero in Colombia.