Determinación del enriquecimiento de metales pesados en las lagunas de Colta y Yambo de la zona 3 del Ecuador

Abstract

Heavy metals in sediments are reported as a serious problem due to their bioaccumulation and toxicity. The aim of the study was to determine the enrichment of heavy metals in Colta and Yambo lagoons, zone 3 of Ecuador. The information collection and the analysis of metals were carried out at the beginning of November 2021 and was concluded in March 2022. The study considered heavy metals such as cadmium (Cd), lead (Pb), manganese (Mn) and iron (Fe), which were analyzed using 3050B (EPA SW 846) method and specifying the determination of metals coupled to atomic absorption spectrometry. In addition, a Pearson correlation coefficient analysis between heavy metals and nutrients such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sodium (Na), magnesium (Mg) and cation exchange capacity (CEC) was performed. Georeferenced maps were also used to interpret the metal concentration distribution patterns throughout the lagoons. Then, it was necessary to apply the geo-accumulation index formula and the enrichment factor was evaluated to determine the value and source of contamination of heavy metal in the sediments of water systems. As a result, it was identified that the highest relevance is found in the Colta lagoon and the metal associated is Cd with an average of 0.27+/-0.05 ppm, unlike the Yambo lagoon where the metals causing a moderate enrichment are Cd 0.37+/-0.04, Pb 3.95+/-0.94 and Mn 92.03+/16.21 ppm respectively. Finally, it was concluded that both lagoons tend to be affected by another source of contamination different than the bedrock; therefore, it is recommended to carry out studies to identify the factors that cause the enrichment of the metals studied.