Baseline values and environmental assessment for metal(loid)s in soils under a tropical rainy climate in a Colombian region.

The baseline values for metal(loid)s in soils are known as a tool for the evaluation, prevention, and monitoring of the environmental quality of the soil. The main aim is to propose baseline values for metal(loid)s through the analysis of the concentrations in soils within natural areas; additionally, this study attempts to assess the environmental quality of soils in agricultural areas. The study was developed in the Piedemonte Llanero from Colombia a region with more than 5000 mm year-1 of pluviometry. A total of 90 soil samples were collected in agricultural and natural areas. Chemical analysis was conducted by acid digestion following the method EPA 3050B and determined the metal(loid)s (Al, As, Fe, Cd, Cr, Cu, Mg, Mn, Ni, Pb, and Zn) through ICP-OES. This is the first time that baseline values are proposed for a region in Colombia. The values proposed (expressed in mg kg-1) are Cd (0.3), As (2.8), Cu (9.9), Ni (10.2), Pb (11.3), Cr (21.1), Zn (28.2), Mn (83.8), Mg (348), Fe (22,775), and Al (28,975). These values are comparatively lower than those reported for other regions in Latin America and the rest of the world. Also, agricultural soils are not contaminated. The possible explanation is as a consequence of the intense washing caused by the intense rainfall of the place. The results also demonstrated that the soils in this region are not contaminated. Finally, these advances will allow public and private organizations to establish criteria for the environmental and sustainable management of soils, especially on agricultural activities.

Chemical vulnerability of red soils in La Mancha (Central Spain).

Red soils are widely distributed in Mediterranean regions. They constitute one of the most important soil resources for crop production and other uses. The main objective of this paper is to estimate the inherent chemical susceptibility of red soils of La Mancha to chemical degradation. Selected 47 soil profiles, were analyzed in the area by means of multivariate analysis; we identified five soil attributes that are well represented in the local soils database, which are most likely to control the chemical vulnerability. These attributes are the calcium carbonate, organic matter and clays together with soil depth and drainage. The attributes were transformed and a simple vulnerability index (VI) was deviced. We concluded that the index may be used as a first approximation rating of La Mancha's red soils vulnerability against an eventual chemical degradation, or to aid resource management and prevent anthropogenic potential impacts.