Recently, calculations of the given parameters of cationic equilibrium in plants, for example Digitalis purpureae, have been very important. For the observed environmental conditions the constants in Czarnowski’s model were as following: flower: 170.64; root: 174.44; leaves: 5.80, and stalk: 266.00. These calculated values are higher in comparison to Scapania undulata, growing in the areas of the Sudety Mountains. The study confirmed that the model may be used to estimate the environmental exposure of the plants.