Isotopic composition and origin of uranium and plutonium in selected soil samples collected in Kosovo

Soil samples collected from locations in Kosovo where depleted uranium (DU) ammunition was expended during the 1999 Balkan conflict were analysed for uranium and plutonium isotopes content ( 234 U, 235 U, 236 U, 238 U, 238 Pu, 239+ 240 Pu ). The analyses were conducted using gamma spectrometry ( 235 U, 238 U ), alpha spectrometry ( 238 Pu, 239+ 240 Pu ), inductively coupled plasma–mass spectrometry (ICP—MS) ( 234 U, 235 U, 236 U, 238 U ) and accelerator mass spectrometry (AMS) ( 236 U ). The results indicated that whenever the U concentration exceeded the normal environmental values (~2 to 3 mg/kg) the increase was due to DU contamination. 236 U was also present in the released DU at a constant ratio of 236 U (mg/kg)/ 238 U (mg/kg)=2.6×10 −5 , indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg and, on the basis of the measured 238 Pu/ 239+ 240 Pu , could be entirely attributed to the fallout of the nuclear weapon tests of the 1960s (no appreciable contribution from DU).