Pu and U Atom Ratios and Concentration Factors in Reservoir 11 and Asanov Swamp, Mayak PA:  An Application of Accelerator Mass Spectrometry

Abstract

Mayak Production Association, East Ural, Russia, was established to produce weapons-grade plutonium. Routine discharges and accidents at Mayak PA contaminated large areas, including the Techa River. The objectives of the present work were to study atom ratios for plutonium and, for the first time to our knowledge, uranium isotopes in water, soil, grass, and aquatic biota samples from Reservoir 11 and the Asanov Swamp, downstream from Mayak PA. Atom ratios (240Pu/239Pu, 236U/235U, 235U/238U) were determined using accelerator mass spectrometry to confirm radionuclide source characteristics and calculate activities and concentration factors for the studied samples. The lowest 240Pu/239Pu atom ratios were consistently found in Asanov Swamp samples (approximately 0.019), indicating a major contribution from early discharges of weapons-grade Pu. 240Pu/239Pu atom ratios in Reservoir 11 were higher, indicating influence from more recent civil reprocessing. The presence of 236U is usually indicative of fuel irradiation; 236U/235U ratios increase from weapons to civil sources. Our new data show that Asanov samples had lower 236U/ 235U ratios than Reservoir 11 samples (0.0005-0.0045 for Asanov compared with 0.0074-0.0153 for Reservoir 11) in agreement with Pu results. Pu and U concentration factors calculated for vegetation and biota samples at Mayak were comparable with corresponding values found in the literature.

Does radioactive contamination affect the shell morphology of the pond snail Lymnaea stagnalis in the exclusion zone of the Chernobyl NPP (Ukraine)?

“…The ecological conditions at these sites, which are influenced by radiation and chemical factories of PA ''Mayak'', have been reported in detail by many authors (Christensen et al 1997;Trapeznikov et al 2000;Standring et al 2002;Børretzen et al 2005;Smagin 2006Smagin , 2007, and only data relevant to the present study are combined here in Table 1.…”

“…Furthermore, some transuranic isotopes, such as 238 Pu, 239?240 Pu, and 241 Am, are also detectable in ecosystem components in all the sampled areas but in significantly lower amount than strontium and cesium (Matsunaga et al 1998;Børretzen et al 2005;Ramzaev et al 2006;Schmieman et al 2007;Smagin 2007).…”

Normal axial skeleton structure in common roach Rutilus rutilus (Actinopterygii: Cyprinidae) and malformations due to radiation contamination in the area of the Mayak (Chelyabinsk Province, Russia) nuclear plant

“…1. Many articles have described the environmental situation in and around Mayak area and along the Techa River downstream of the nuclear plant and some of the radiological consequences of this contamination (Trapeznikov et al , 1993, 1994; Wakerley, 1995; Christensen et al , 1997; Kryshev et al , 1997; Avramenko et al , 2000; Standring et al , 2002; Sadovnikov et al , 2003; Børretzen et al , 2005). The principal situation that has led to environmental contamination in the area are the following: (1) discharge of large quantities of liquid radioactive waste into the Techa River (originating from Lake Irtyash, Tobol–Irtysh system, Ob’ River drainage) in 1949–1956, (2) explosion in 1957 of a tank containing high level liquid radioactive waste, leading to the contamination of an area of c. 20 000 km 2 ; this is known as the Kyshtym accident; large‐scale territorial contamination caused by this accident is known as the East Urals Radioactive Trace, (3) wind resuspension in 1967 of exposed Lake Karachay sediments, which was a storage pond for liquid radioactive waste, that led to the dispersal of 20 TBq of radioactive dust around the installation and (4) radioactive waste in water bodies in the Techa Cascade Reservoirs (TCR).…”

Radionuclide contamination of sediment deposits in the Ob and Yenisey estuaries and areas of the Kara Sea

“…The upper Techa sediments, notably in the Asanov Swamp downstream from Reservoir 11, still contain artificial radionuclides from previous direct discharges: estimates of 37 TBq 90 Sr and 185 TBq 137 Cs in surface soils have been reported (Romanov, 1995). Asanov Swamp sediments also contain trace amounts of weapons-grade plutonium (Børretzen et al, 2005).…”