Evaluación de índice de geoacumulación de metales en sedimentos de la laguna Magdalena del sistema lacustre de Atillo del Parque Nacional Sangay

Abstract

The aim of the current research supported by GIDAC was to evaluate the metal geoaccumulation indices in sediments of Magdalena lagoon, which is part of the Atillo lake system, located in Sangay National Park, Guamote county, Chimborazo province. Twenty-four simple random sampling were defined under the accessibility criteria in order to encompass the entire study area. The sampling was carried out in January 2022 with a boat and a Van-Ven type dredger and using the Atomic Absorption Spectroscopy (A.A.S.) technique as well as the Thermo Fischer Scientific equipment, metal concentrations (Mn, Cd, Fe and Pb) and nutrients (P, N, K, Na, Mg and Ca) were determined. To reflect the spatial variability of metals, ArcGIS 10.3 and the inverse distance weighted (IDW) method were used. A Pearson correlation between metal and nutrient concentrations was also performed. The enrichment factor and geoaccumulation indices were evaluated in order to establish the origin and level of metal contamination in lake sediments. The average concentrations for metals are: Mn=307.11 ppm, Cd=0.46 ppm, Fe=4261.24ppm and Pb=1.38 ppm; while for nutrients are: P=0.25 ppm, N=0.34%, K= 55.31ppm, Na=41.17ppm, Mg=79.99ppm and Ca=1368.67ppm. The (IDW) method showed a medium spatial variability for Cd, Fe, Mn and a low spatial variability for Pb. The Pearson correlations established inversely proportional relationships between the concentrations of K and Mn, Na and Mn with values of -0.71 and -0.85 respectively. The enrichment factors for Fe, Mn and Pb indicate that they come from the bedrock, while Cd comes from the bedrock and an additional source. The geoaccumulation indices revealed the lack of contamination caused by Mn, Cd, Fe and Pb in the lake sediments of Magdalena Lagoon. It is recommended to carry out further studies for Cu, Ni, Bi, Zn metals, which are present in the sediments of Atillo lake system adjacent lagoons.