The sediment samples collected near the shore from Romania were used for the determination of levels of natural 210Pb, 226Ra and fallout 137Cs radionuclides. The sediment samples were dried and ground to a fine powder. Airtight sealed samples were counted by gamma-spectrometer with 110 cm3 well-type HPGe detector for one week each. By using the isotopic analysis results, sediment accumulation rate was determined. A sedimentation rate of 0.20±0.01 cm·y-1 was determined using 210Pb method and 0.15±0.03 cm·y-1 using 137Cs isotope. Fallout peak from Chernobyl reactor accident, as well as the peaks due to nuclear tests, act as time markers.