Dating of Black Sea sediments from Romanian coast using natural²¹⁰Pb and fallout¹³⁷Cs

Abstract

The sediment samples collected near the shore from Romania were used for the determination of levels of natural 210 Pb, 226 Ra and fallout 137 Cs 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 210 Pb method and 0.15±0.03 cm. y-1 using 137 Cs isotope. Fallout peak from Chernobyl reactor accident, as well as the peaks due to nuclear tests, act as time markers.

Variation of sedimentation rate in the semi-enclosed bay determined by 137Cs distribution in sediment (Kaštela Bay, Croatia)

“…It has been established that urbanization and industrialization are among the processes with the largest direct influence on the sedimentation rate changes in the coastal areas (Lu and Matsumoto, 2005). 137 Cs is probably the most frequently used anthropogenic radionuclide for monitoring of the environmental processes (Ayçık et al, 2004;Saxena et al, 2002). It is also one of the most frequently applied tracers for determination of recent sedimentation rates in aquatic environments (Ahn et al, 2006;Kumar et al, 2007;Laissaoui et al, 2008;Lu, 2004;San Miguel et al, 2004;Yao et al, 2008).…”

Radiochronological Methods as Tools to Study Environmental Pollution

“…The radionuclide 210 Pb (t 1/2 = 22.3 y), a member of the natural radioactive decay series of 238 U, provide a reliable possibility of dating sediments over the last 200 years [1]. This technique has since seen further refined and very widely used by many researchers [2][3][4][5][6][7][8][9][10][11]. This method of dating, requires the complete recovery of the topmost sediment layers.…”

“…We have used the above mentioned radioisotopic methods over the years for the dating of sediments from Lakes Zurich and Constance, the sea of Marmara, southern Turkey, eastern Spain, the Black Sea region and northern Cyprus [5][6][7][8][9][10][11].…”

Sedimentation rates, nitrogen and phosphorus retentions in the largest urban Lake Donghu, China

“…10 9 y) series and it is involved in the sedimentary processes through the following events. [5][6][7][8][9][10] The noble gas nuclide 222 Rn (T 1/2 = 3.82 d), a member of 238 U decay chain, diffuses out of the earth's crust and is emitted into the atmosphere from the lithosphere, surface water and airborne dust. Radon remains in the atmosphere until it decays.…”

“…[7][8][9]11 In addition, the distribution pattern of 137 Cs (T 1/2 = 30.14 y) present in sediments represents time markers and it is used as a method of dating. 10 This method assumed that 137 Cs fallout with rain became attached to particles and that these particles were quickly (<1 year) transported from the drainage basin to lake sediment. 137 Cs falling directly upon the lake surface is adsorbed onto suspended particulate matter and sedimented.…”