Six combined samples of filter ash obtained by lignite combustion in the "Nikola Tesla A" Power Plant were subjected to a five-phase sequential extraction. In order to establish associations of extracted trace and major elements, obtained concentrations were subjected to intraphase and interphase correlation analysis. Statistical analysis revealed the pollution potential, association forms of trace and major elements with the inorganic matrix, binding pattern of adsorbed and ion-exchangeable fractions to the inorganic matrix, and changes in association forms occurred during and after lignite combustion.