Radioecology Research of The Red Forest Proving Ground

By Світлана Миколаївна Чеснокова Published January 17, 2018 2001 and previously

Period: since 2001

Customer: Texas Tech University (USA)

Project objective: study characteristics of radionuclides horizontal and vertical distribution in the soil of the Red Forest Proving Ground; assess radionuclides migration parameters.

The following works were performed within the framework of the project:

vertical and surface distribution of 90Sr, 134, 137Cs, 154, 155Eu, 241Am and 238+239+240Pu were analyzed in 435 points of the Red Forest Proving Ground;
agrochemical description of soils was performed based on the data obtained for eleven 1.5-meter sections.

Research results:

It was confirmed that vertical distribution of radionuclides in soil profile is characterized by a vivid exponential character. As per summer 2001, more than 90% of 90Sr stock were in surface soil layer of 0-10 cm, for 137Cs and 238,239,240Pu this figure amounts to 93% and 97%, correspondingly. However, in 17% of the cases, vertical distribution has vivid dislocation (apparently of biogenic origin) with significant deepening of the activity stock. Indexes of 90Sr vertical migration are higher than those of 137Cs: there is 17–27% more 90Sr than 137Cs in 10–30 cm soil layers. Still less plutonium isotopes migrate deep down the soil.
Surface distribution of the activity is extremely irregular with a westward ‘trace’ of radioactive cloud.
The assessments performed reveal that at some sites of The Red Forest the contamination level is equal to the one of 1986 fallout: for 137Cs it is up to 360-750 MBq/m2, and for 90Sr it is up to 200-450 MBq/m2. Average values of plutonium isotopes’ areal activity amount to 0/96–1/65 MBq/m2. The correlation of radionuclides activity in the proving ground soil confirms multifold contamination of the area: initially, by the thermal explosion products, and then, even more, by the products of its burning.