[en] It is stated that minute concentrations of a number of metals have been detected in the stratosphere. These, having no volatile precursors, enter the stratosphere as particles. Their main source seems to be the surface of the Earth. Data on the nature of such sources is scarce and measurements of the concentrations of stable Pb, ²²⁶Ra and its radioactive daughter ²¹⁰Pb were made. Aerosol samples over Poland were collected from heights of 6 to 12 km, during 1973-1975, using PVC fibre filters placed in collectors suspended under the wings of jet aircraft, and the quantities of ²²⁶Ra, stable Pb, ²¹⁰Pb, ⁹⁰Sr and ¹³⁷Cs were determined using conventional methods. Results are presented graphically. (U.K.)