Modern parameters of caesium-137 root uptake in natural and agricultural grass ecosystems of contaminated post-Chernobyl landscape, Russia

Authors : Tatiana PARAMONOVA, Ekaterina MACHAEVA, Belyaev VLADİMİR

Pages : 30-37

Doi:10.18393/ejss.56716

View : 55 | Download : 13

Publication Date : 2015-01-08

Article Type : Research Paper

Abstract :The estimation of modern parameters of 137 Cs root uptake was conducted in natural meadow and agricultural ecosystems of post-Chernobyl landscapes of Tula region. The agrosystems with main crops of field rotation insert ignore into journalissuearticles values(barley, potatoes, rape, maize); occupying watersheds and slopes with arable chernozems are contaminated at a level 460-670 Bq/kg insert ignore into journalissuearticles values(4.7-6.0 Ci/km 2 );; natural meadow ecosystems occupying lower parts of slopes and floodplains are contaminated at a level 620-710 Bq/kg insert ignore into journalissuearticles values(5.8-7.6 Ci/km 2 );. In the arable soils 137 Cs uniformly distributed to a depth of A p horizon insert ignore into journalissuearticles values(20-30 cm of thickness);, while in meadow soils 70-80% of the radionuclide is concentrated within the top A d horizon insert ignore into journalissuearticles values(9-13 cm of thickness);. These topsoil layer accords with rhizosphere zone, where >80-90% of plant roots are concentrated, and from which 137 Cs is mostly consumed by vegetation. Total amount of 137 Cs root uptake depends on the level of soil radioactive contamination insert ignore into journalissuearticles values(correlation coefficient 0.61);. So 137 Cs activity in meadow vegetation insert ignore into journalissuearticles values(103-160 Bq/kg); is generally more than one in agricultural vegetation insert ignore into journalissuearticles values(9-92 Bq/kg);. The values of 137 Cs transfer factor in the studied ecosystems vary from 0.01 insert ignore into journalissuearticles values(rape); to 0.20 insert ignore into journalissuearticles values(wet meadow);, that confirms the discrimination of the radionuclide’s root uptake. The larger are the volume of roots and their absorbing surface, the higher are the values of transfer factor from soil to plant insert ignore into journalissuearticles values(correlation coefficients 0.71 and 0.64 respectively);. 137 Cs translocation from roots to shoots is also determined by biological features of plants. At the same level of soil contamination above-ground parts of meadow herbs accumulate more 137 Cs than Gramineae species, and in agrosystems above-ground parts of weeds concentrate more 137 Cs than cultivated cereals. Thus, the level of soil radioactive pollution and biological features of plants are determinants in the process of 137 Cs root uptake and translocation and should be considered in land use policy.
Keywords : radioactive contamination, caesium 137, root uptake, transfer factor, Chernobyl accident

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