Abstract <p>New data on the concentrations of ions of the main salt composition and dissolved trace elements in the waters of the mouth section of the Kolyma River and its lower tributaries (the Omolon, Maly Anyuy, Ambolikha, and Panteleikha) during the decline of the spring–summer flood and summer–autumn low water are presented. Arguments are given proving the presence of two genetic components in the waters of the mouth part of the Kolyma River, which have different macro- and trace element composition. A regular change in the TDS and trace element composition of river runoff into the seas of the Russian Arctic from west to east is shown, presumably associated with an increase in the prevalence of permanent permafrost in catchment areas in this direction.</p>