Identification of tritium-contaminated areas using a tritium survey on the snow cover, the case of Semipalatinsk test site.

The article presents research findings on the content of tritium in the snow cover of test locations 'Balapan' and 'Sary-Uzen' in the territory of the Semipalatinsk Test Site. Based upon results, a number of tritium-contaminated areas were revealed. At the 'Balapan' site, elevated tritium concentrations in the snow were revealed in the vicinity of the 'Atomic lake' close to the 'Karazhyra' deposit and at the location of Lake 'Kishkensor'. At the 'Sary-Uzen' site, elevated tritium concentrations in the snow were discovered near borehole 101, at object 'Lazurite' and at an unnamed creek outflowing from the mountain range. Maximal of tritium activity concentration in the snow were 45 Bq/kg and 36 Bq/kg at the 'Balapan' and 'Sary-Uzen' sites, respectively. Background tritium concentrations in the snow cover of the STS territory were found to be 4.6-12 Bq/kg.

The character of radionuclide contamination of natural lakes at the territory of the Semipalatinsk test site.

The paper presents data on the research of the radionuclide contamination redistribution in the ecosystems of natural lakes at the Semipalatinsk test site and adjacent territories. Natural lakes, which are the research objects, are located on the territory of the test sites, in the zone of their influence, in the zone impacted by radioactive fallout or in the "background" territories. Sampling of water, bottom sediments and plants was carried out, in which the content of radionuclides 241Am, 137Cs, 90Sr and 239+240Pu was determined. Based on the obtained quantitative data, distribution coefficients (Kd) for sediments and water, as well as concentration ratio (FV) for plants and sediments were calculated.

Researching of tritium speciation in soils of "Balapan" site.

Speciation of tritium (3Н) in soils from the "Balapan" site in Semipalatinsk are presented in this study. Three interrelated objects were chosen for further study: "Atomic" lake, the Shagan River and an external reservoir. The main speciation forms of 3Н in soil were: 3Н in surface-adsorbed water, 3Н in interlayer water, hydroxylic 3Н, organically bound 3Н and crystalline-bound 3Н. Results will allow an estimation of contamination mechanism to be made, and will also allow the potential for migration and bioavailability of 3Н to be assessed.

Radionuclide transport in the "sediments - water - plants" system of the water bodies at the Semipalatinsk test site.

This paper provides research data on levels and character of radionuclide contamination distribution in the «sediments- water - plants ¼â€¯system of objects of the Semipalatinsk test site (STS). As the research objects there were chosen water bodies of man-made origin which located at the territory of "Experimental Field", "Balapan", "Telkem" and "Sary-Uzen" testing sites. For research the sampling of bottom sediments, water, lakeside and water plants was taken. Collected samples were used to determine concentration of anthropogenic radionuclides 90Sr, 239+240Pu, 241Am, 137Cs. The distribution coefficient (Kd) was calculated as the ratio of the content of radionuclides in the sediments to the content in water, and the concentration ratio (FV) was calculated as the ratio of radionuclide content in plants to the content in sediments or soil.

Mechanisms for surface contamination of soils and bottom sediments in the Shagan River zone within former Semipalatinsk Nuclear Test Site.

The Shagan River is the only surface watercourse within the former Semipalatinsk Test Site (STS). Research in the valley of the Shagan River was carried out to study the possible migration of artificial radionuclides with surface waters over considerable distances, with the possibility these radionuclides may have entered the Irtysh River. The investigations revealed that radioactive contamination of soil was primarily caused by the first underground nuclear test with soil outburst conducted at the "Balapan" site in Borehole 1004. The surface nuclear tests carried out at the "Experimental Field" site and global fallout made insignificant contributions to contamination. The most polluted is the area in the immediate vicinity of the "Atomic" Lake crater. Contamination at the site is spatial. The total area of contamination is limited to 10-12 km from the crater piles. The ratio of plutonium isotopes was useful to determine the source of soil contamination. There was virtual absence of artificial radionuclide migration with surface waters, and possible cross-border transfer of radionuclides with the waters of Shagan and Irtysh rivers was not confirmed.