A study made on the geochemistry of gaseous products for the Tolbachik basaltic eruption in Kamchatka (1975--1976) has shown that magmatic gases, submicron ash, and aerosols are enriched in chalcophile elements. Active volcanism represents one of the main sources. The annual input of chalcophile elements from the volcanoes of the world to the atmosphere is found to be in agreement with the amounts brought into the oceans by the water-soluble component of the river runoff.