In present study, Activity concentrations of Pb-210 (Polonium-210) were indirectly determined by utilizing alpha spectrometry. Sediment chronology was obtained by using Pb-210 (CF; CS, CRS, CIC) models and corrected via residence time of the Pb-210 in each core for Lake Karagol. Average residence times of the Pb-210 is 6.5, 4.8, 5.3 months and average sedimentation rate is 0.366, 0.322, 0.237 cm year(-1) in S-1, S-2, S-3 stations respectively. According to atmospheric Pb-210 flux (24 mBq cm(-2) year(-1)) and Po-210/Pb-210 ratio values, we determine the soil erosion in the lake catchment. The ranges of ratios in the sediment cores obtained from Lake Karagol are 1.4-1.3, 1.5-1.2, 1.3-1.1 in S-1, S-2, S-3 stations respectively. In terms of Enrichment Factor, heavy metal concentrations are lower than the antropogenic values. So we can say that the elements originate from the continental supply. In other words there is not metal pollution in the lake.