Dataset of iodine concentration in soils and grassland vegetation and radioactive contamination of pastures of the regions of the Russian Federation affected by the Chernobyl NPP accident
Description
The dataset includes information of spatial location of the sampling points: longitude and latitude (in degrees) and altitude (in meters) in WGS-84 coordinates system (fig. 1), region, district of the region and the locality name.
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The field studies were conducted between the years 2008 and 2022, during the vegetation period. Sampling was carried out on pastures located in the vicinity of rural settlements in the Bryansk and Oryol regions of the Russian Federation. The settlements under investigation were situated in areas affected by varying degrees of radioactive iodine fallout and were located on different types of soils. In each of the settlements under study, the pastures were selected according to the terrain, with autonomous and subordinate areas being considered. During the field survey of the test pastures, the following procedure were carried out: 1) georeferencing the sampling point coordinates using GPSmap 62 stc (Garmin, USA) in WGS-84 coordinate system; 2) selection of the representative sampling points, taking into account that terrain, soil, and vegetation are typical for the pasture; 3) measurement of soil 137Cs contamination density using a portable gamma-spectrometer Violinist III (TSA Systems ltd., USA) with a scintillation detector of SPA-3 type with NaI(Tl) crystal; 4) measurement of gamma radiation equivalent dose using MIRA-661 (Genitron Instruments GmbH, Germany) and RadiaCode-101 (Scan Electronics LLC, Russia) dosimeters with a scintillation detector with CsI(Tl) crystal. The sensor was situated on the ground surface and the measurements exposition was 90 s; 5) cutting an average sample of the grasses from a 20 × 20 cm or 40 × 40 cm areausing shears at a height of 2 cm from the soil surface. Where available, additional sampling of Trifolium and Deschampsia was separately conducted. 6) soil type and texture determine according to Russian Soil Register and WRB; 7) soil sampling with a soil sampling tube from the top 20 cm layer with partition of the probe in 3 layers: 0-5 cm, 5-10 cm, 10-20 cm. Chemical analysis of the samples was conducted in the Vernadsky Institute. The iodine content in soils and plants was determined by the kinetic method of Proskuryakova and Nikitina. The reaction speed was determined by measuring the change in light absorption of the solution, which is coloured with iron rhodanide and has an orange-red colour. The colour of the solution changes upon oxidation of rhodanide, with the concentration of iodine in the solution influencing the speed of this process. This is demonstrated by the decrease in the optical density of the solution, as measured by a photoelectrocolorimeter KFK-3-01 (ZOMZ, Russia) at specific time intervals. The determination error was less than 5%. For chemical determination of iodine content in soil a 0.5 g sample was filled with 30% K2CO3 solution, dried and calcined at 480 °C. The calcined sample was transferred into a 50 ml solution. For chemical determination of iodine content in vegetation a 0.2 g sample was filled with 3% K2CO3 solution, dried and calcined at 480 °C. The calcined sample was centrifuged and transferred into a 10 ml solution.
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Funding
The data collection was founded by the state task of the laboratory of biogeochemistry of environment of the Vernadsky Institute of Geochemistry & Analytical Chemistry of the Russian Academy of Sciences (GEOKHI RAS).