The sediment samples collected near the shore from Romania were used for the determination of levels of natural Pb-210, Ra-226 and fallout Cs-137 radionuclides. The sediment samples were dried and ground to a fine powder. Airtight sealed samples were counted by gamma-spectrometer with 110 cm(3) 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 Pb-210 method and 0.15+/-0.03 cm.y(-1) using Cs-137 isotope. Fallout peak from Chernobyl reactor accident, as well as the peaks due to nuclear tests, act as time markers.