The concentration of metals was determined by atomic absorption spectrophotometry (AAS) in the laboratory of Geochemistry PGI FEB RAS, using a Shimadzu 6800 instrument (Japan) in flame (Cu, Zn, Cd, and Ni) and flameless (Pb) versions. The error in the determination of the content of copper, zinc, manganese and cadmium is 10%, and the error for nickel and lead is up to 30%.