Biomonitoreo empleando líquenes y briófitos para la evaluación de la calidad atmosférica de la ciudad de Chunchi, provincia de Chimborazo

Abstract

The city does not have a record of nitrogen dioxide and sulfur dioxide atmospheric emissions, which are produced mainly by vehicular traffic. The aim of the current graduation work was to analyze the atmospheric quality in the urban area of Chunchi city through the application of biological monitors to determine the appropriate epiphytes to be used as biomonitors. For this research, it was necessary to work with lichens and bryophytes. Through tolerance tests, 3 species of lichens and 4 species of bryophytes were exposed to contaminated environments, then the absorbance parameter of each species was obtained by UV-Visible spectrophotometry, the lichen species Heterodermia leucomelos and the bryophyte species Fabronia ciliaris were the most suitable species to be used as biological monitors. Thirty monitoring points were installed throughout the study area, both species were exposed twice, during a month. The concentrations of NO2 and SO2 expressed in µg/m3 and captured during these periods by the epiphytes were determined by spectrometry. The results of the study reveal that the levels of atmospheric pollutant concentrations are within the permissible limits established by the Ecuadorian environmental regulations and the World Health Organization. The species F. ciliaris absorbed 35% more nitrogen dioxide and 3% more sulfur dioxide than H. leucomelos; thus, it is concluded that F. ciliaris can accumulate higher concentrations of pollutants than H. leucomelos and the highest levels of pollutant concentration are found in areas with heavy vehicular traffic like Panamerican Highway, Troncal Sierra and Bermeo Vallejo Street.