In the present research the investigation of the content of the scum of Chisinau power station 2 was carried out. The samples of the scum were analyzed for the presence of macrocomponents and toxic elements (23 components). Sample decomposition was carried out by three methods: fusion with sodium carbonate, acid decomposition and water extract. To determine chemical composition of the scum, a complex of chemical and physicochemical methods was used: gravimetric, titrimetric, photocolorimetric, flame photometry and flame atomic absorption spectrometry. To increase sensitivity and exclude the influence of the matrix during determination of cadmium and lead by flame atomic absorption spectrometry, a concentration by extraction of complex compounds of metals with N, N-diethylthiocarbamate by butyl acetate was carried out. Mercury was detected by the “cold vapor” method. The accuracy of the detection was evaluated using standard sample, as well as by comparing the results obtained by different methods of sample decomposition and different methods of analysis, the limits of detection were estimated. A correlation between carbon as a component of carbonates and total carbon was carried out. The carbon contained in the samples of the scum was shown to be of carbonate origin. All analyzed samples were shown to be salts of alkaline earth elements, mainly of calcium. By the content of anions, three samples are carbonate, two are mixed carbonate-sulfate, and one is carbonate-silicate-sulfate. The content of the toxic metals in all analyzed samples is insignificant. Organic compounds are absent in the analyzed samples.