The determination of the radionuclides of U- and Th-series as well as of 40K and 137Cs in soils and waters in a lignite mining area was performed. The measurements in the soils were undertaken by γ-ray spectrometry while the concentrations of 234U and 238U in waters and the isotopic ratio 234U/238U were determined by α-ray spectrometry. Slight seasonal variation of the radioactivity was observed with high values in summer and low in winter. The estimated annual radiation dose from soil was lower than the worldwide average whereas in the case of water only one location showed increment in the internal radiation about 18 % of the worldwide average.