Evaluation of the presence of heavy metals in agricultural soils and crops in three microbasins of the municipality of Poopó - Bolivia

Lourdes Jhanneth Chambi Parisaca; Vladimir Orsag Céspedes; Amalia Niura Zurita

Abstract

The purpose of the study was to determine the presence of heavy metals (Pb, Cd, Zn and As) in agricultural soils and representative crops in three micro basins in the Poopó municipality; divided into three parts (high, medium and low). Soil from agricultural plots and edible fraction crops (potato, bean, barley and alfalfa) were sampled, according to availability, in the micro basin of Sale and Mean (P1), Coriviri (P2) and Poopó (P3). Samples with small concentrations were determined using the atomic absorption spectrophotometer in flame and graphite furnace, in the laboratory of the Chemical Research Institute of La Paz, Universidad Mayor de San Andrés. The concentration of metals was evaluated with the maximum permissible limits and the levels dangerous for soil, proposed by the Dutch Environmental Agency and the Environmental Management Law of Ecuador, the agricultural crops were evaluated with the maximum contents proposed by Kabata (2000). The results show that the agricultural soils of the three micro-basins under study are contaminated with arsenic, surpassing the dangerous level of (55 mg kg-1 of soil), via the natural mineralization of the area and the contribution of the surrounding mining in the Region (Clearing, Copagira waters thrown in the open and to the rivers), a situation that deserves immediate remediation, in order to avoid the intensity of accumulation. The cultivation of edible bean fraction presents tendencies of greater accumulation of arsenic, reaching in some cases to exceed the maximum content in cultures (1.7 mg kg-1 of sample).