Pu-239+240 i Pu-238 u zemljištu Crne Gore - porijeklo i koncentracije aktivnosti

Abstract

Mjerenja koncentracija aktivnosti 239+240Pu i 238Pu u uzorcima zemljišta iz Crne Gore vršena su u Minsku (BelGIM) i u Helsinkiju (STUK), utvrđeni su njihovi međusobni odnosi, kao i odnosi koncentracija plutonijumovih izotopa i 137Cs. Na osnovu toga je diskutovano i njihovo porijeklo, a na osnovu aktivnosti 137Cs izmjerenih na teritoriji Crne Gore na 91 lokaciji (67 – samo površinski sloj, 24 – slojevi: 0-5 cm, 5-10 cm i 10-15 cm) procijenjeni su i u ovom radu predstavljeni nivoi aktivnosti Pu izotopa.

The measurements of 239+240Pu and 238Pu activity concentration in soil samples from Montenegro, together with 137Cs activity measurements in the same samples, were used to determine the activity ratios enabling a discussion about origin of these radionuclides, as well as estimating Pu isotopes level in soils at the territory of Montenegro. The 239+240Pu/137Cs activity ratio was found to be with an average of 0.020 and standard deviation of 0.007, the 238Pu/137Cs – with an average of 0.0006 and standard deviation of 0.0003, the 238Pu/239+240Pu – with an average of 0.030 and standard deviation of 0.007, confirming that plutonium isotopes, today present at the territory of Montenegro, originated from the global fallout. These, as well as the other results showed that 137Cs today present at the territory of Montenegro predominantly has the Chernobyl’s origin. Based on 137Cs activity concentrations in the Montenegro soils measured in the period 1994-2011, using in situ and standard laboratory HPGe spectrometric method, levels of soil contamination with plutonium isotopes have been evaluated and discussed – for 91 locations (67 – surface soil only, 24 – layers: (0-5) cm, (5-10) cm and (10-15) cm). The highest measured 137Cs activity in top soils in 1994 was 740 Bq/kg, in 2001 – 1710 Bq/kg, in 2002 – 2011 Bq/kg, in 2011 – 413 Bq/kg, while the highest estimated (and measured) 239+240Pu in 2011 – 8.3 Bq/kg.