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Plutonium isotopes 238Pu, 239+240Pu, 241Pu and 240Pu/239Pu atomic ratios in the southern Baltic Sea ecosystem

Strumińska-Parulska D.I., Skwarzec B.

Oceanologia

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2010

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No. 52 (3)

499-512

EN

The paper summarizes the results of plutonium findings in atmospheric fallout samples and marine samples from the southern Baltic Sea during our research in 1986-2007. The activities of 238Pu and 239+240Pu isotopes were measured with an alpha spectrometer. The activities of 241Pu were calculated indirectly by 241Am activity measurements 16-18 years after the Chernobyl accident. The 240Pu/239Pu atomic ratios were measured using accelerator mass spectrometry (AMS). The 241Pu activities indicate that the main impact of the Chernobyl accident was on the plutonium concentration in the components of the Baltic Sea ecosystem examined in this work. The highest 241Pu/239+240Pu activity ratio was found in sea water (140 š 33). The AMS measurements of atmospheric fallout samples collected during 1986 showed a significant increase in the 240Pu/239Pu atomic ratio from 0.29 š 0.04 in March 1986 to 0.47 š 0.02 in April 1986.

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Sedimentation rates and dating of bottom sediments in the Southern Baltic Sea region

Suplińska M. M., Pietrzak-Flis Z.

Nukleonika

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2008

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Vol. 53, suppl. 2

105--111

EN

Sedimentation rates and dating of bottom sediments were estimated in two sampling stations of the Gulf of Gdańsk and in four stations in the open sea area. Estimations were based on vertical distributions of 210Pb, 137Cs and 239,240Pu activity concentrations in sediment core samples taken in 1998–2007. Two dating models based on changes of activity concentrations of 210Pbunsup were used: 1) CF:CS (Constant Flux Constant Sedimentation rate-model) and 2) CRS (Constant Rate of Supply-model). 137Cs and 239,240Pu were applied as time markers. 137Cs originates mostly from the Chernobyl accident in 1986, whereas 239,240Pu comes from the global fallout in 1963. The validation of the 210Pb methods was performed by activity peak of 137Cs and 239,240Pu. Sediment accumulation rate (g·cm–2·y–1) was constant along sediment core. Annually accumulated layer, (mm·y–1) decreased with sediment depth in all the locations. In the Gulf of Gdańsk sedimentation rate in the upper layer was about 3.6 mm·y–1, and it decreased in the deeper layers to about 1.1 mm·y–1. Sedimentation rates in the open sea area were lower than in the gulf region and the lowest was observed in the Bornholm Deep, being about 0.95 mm·y–1 in the upper layer and 0.35 mm·y–1 in the deeper layer. The growth of a 5 cm thick layer took 27–37 years in the Gulf of Gdańsk, and 61–105 years in the open sea area. It is suggested that the mean values obtained from the models would give a most reliable estimation of the sedimentation rates.

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Plutonium isotopes 238Pu, 239+240Pu and 241Pu in the Baltic Sea ecosystem

Strumińska D. I., Skwarzec B., Mazurek-Pawlukowska M.

Nukleonika

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2005

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Vol. 50,suppl.1

45-48

EN

In the paper there are presented the results of plutonium 238Pu, 239+240Pu and 241Pu determination in different samples of the Baltic Sea environment. 238Pu and 239+240Pu isotopes were measured in alpha spectrometer and 241Pu results were calculated indirectly by activity measurements of 241Am isotope increase from b-emitting 241Pu in 16-18 years after Chernobyl accident. The results indicate that the Baltic organisms accumulate plutonium from environment and the bioconcentration factors (BCF) range from 100 for fish to 27,000 for priapulida (benthic organisms) and only 0.1% of total plutonium is deposited in living organisms. Almost whole plutonium is deposited in Baltic sediments (about 99%). The results of 241Pu determination indicate that after Chernobyl accident indicate on its high concentration in analyzed components of the Baltic Sea ecosystem and the highest value of the activity ratios 241Pu/239+240Pu were found in seawater (140).