[en] Despite of the history of artificial radionuclides (¹³⁷Cs, ⁹⁰Sr etc.) influence on biota is limited to only a few decades the overwhelming majority of present-day radioecological investigations are connected with studies of redistribution in the environment and biological action of this group of radionuclides. Far less attention has been paid to radiation risk to people and the environment caused by exposure to ionizing radiation originating from naturally occurring radioactive materials. Enhanced natural radioactivity (TENORM) touches a lot of aspects of our common life, starting from occupational risk at work places, through some 'contaminated' goods or even a visit in a spa, and ending on a huge amount of bulk waste materials very often dumped in our vicinity. Each particular way of occurring of natural radioactivity determines some unique scenario of exposure, usually differing from those ones caused by artificial radionuclides. Moreover, consequences of natural radioactivity's occurrence can be assessed from different points of view. Sometimes the public comprehension of this phenomenon is a plentiful source of very serious effects far more detrimental and painful than the direct exposure to radiation. Risk caused by naturally occurring radioactivity is a case where enforcing of ALARA rule became very complex and multidimensional. To prepare a coherent system rules and recommendation designated for the monitoring and control of risk related to the presence of natural radioactivity it is necessary at the very beginning to precise causes of concern and define the clear terms for describing risk scenarios. After that the data concerning inventory of radionuclides activity concentration, their availability and migration, transfer to biota factors, dose assessment had been collected, the effects on biota at the molecular level could be evaluated. In this article an example of such a complex risk assessment was described on base of post mining areas in Upper Silesia, Poland. (author)