Thermal power plants rely on fossil fuels such as coal, oil, or natural gas to produce heat, but they are significant contributors to environmental pollution, emitting metals and other harmful substances. However, the utilization of Fourier Transform Infrared Spectroscopy (FTIR) methods to assess atmospheric pollution in disturbed tropical environments using the spectral properties of lichens has been underexplored. In this study, toxitolerant foliose lichen, Pyxine cocoes (Sw.) Nyl. was collected from various disturbed sites around Panki and Feroze Gandhi Unchahar National Thermal Power Plants (TPPs) in Uttar Pradesh, India and subjected to FTIR analysis. The objective was to investigate and compare the functional groups associated with metal accumulation in lichen thalli.
Results of the FTIR analysis revealed similar absorption bands in appearance but varying in intensity, indicating that both TPPs produce comparable chemical components with varying metabolite quantities. The identified specific functional groups responsible for distinct characteristics within the chemical composition of phytochemical compounds in lichens. The presence of metabolites in P. cocoes spectra enhanced the detection probability of IR bands in various regions, including 3500-3300 cm-1 (N-H and O-H groups), 3300-2500 cm-1 (O-H stretching; carboxylic acid), 1450-1400 cm-1 (C=O symmetric stretching –COO-). FTIR offers a faster and more reliable approach, particularly with the cost-effectiveness and wide distribution of lichens. This study highlights the valuable information obtained through FTIR analysis, which enhances understanding of chemical involvement in polluted environments.