Abstract

COCA-SALAZAR, Alejandro et al. Accumulation of potentially toxic elements in peri-urban agricultural areas of Cochabamba, Bolivia. RevActaNova. [online]. 2023, vol.11, n.1, pp.17-27.  Epub Mar 31, 2023. ISSN 1683-0789.  https://doi.org/10.35319/acta-nova.202313.

Agricultural soils located in peri-urban zones are at risk of contamination with potentially toxic elements due to their proximity to urban and industrial areas. The accumulation of these elements may affect ecosystem functioning and be hazardous for human health, consequently, evaluation of their concentrations is essential to determine accumulation patterns and to implement remediation measures if required. This study evaluated the concentrations of potentially toxic elements Mn, Zn, Pb, Cu and Cd in agricultural fields and irrigation canals of two peri-urban agricultural areas (Martillo and Tamborada) of Cochabamba, Bolivia. Soil and sediment samples were collected from agricultural fields and irrigation canals and their pH, electrical conductivity, organic matter, and the concentrations of Mn, Zn, Pb, Cu and Cd were determined. The results suggest accumulation of Zn, Cu and Mn in irrigation canals of both agricultural areas. Comparison of Tamborada and Martillo agricultural soils suggest Pb and Zn accumulation in Tamborada, while focal Cd accumulation was observed in Martillo. Element concentrations were within natural range variation of uncontaminated soils except for Zn in irrigation canals of Tamborada. The use of wastewater for irrigation, automobile-related diffuse pollution and the dumping of solid wastes in agricultural areas are potential contamination sources. While the alkaline, saline soils with loam and clay texture would contribute to reduce the bioavailability of potentially toxic elements, in the long-term, accumulation could lead to contamination and increase the risk of environmental and health hazard. The median concentrations for Mn, Zn, Pb and Cu (550.74, 75.95, 32.35 and 31.95 mg kg-1, respectively) are suggested as baselines values for the area.

Keywords : Heavy metals; micronutrients; soil contamination; baseline concentration; diffuse pollution.

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