Cartographic evaluation of the risk of Cu, Co and I deficiency in the soil cover of the Central Federal District (Russia) provoking spatial variation of the endemic morbidity level

The Central Federal District (CFD) of Russia is a highly populated area with a developed infrastructure where agriculture specializes in the cultivation of cereals, vegetables, sunflowers, and cattle breeding. The territory is also known for a deficiency of Cu, Co and I in the environment and respectively in the main agricultural plants and animals cultivated in the CFD, as well as in the diets of the local rural and urban population living on local products.

The cartographic basis used for the creation of preliminary assessment maps of the distribution of trace elements in the soil cover of the region was the Unified State Register of Soil Resources of Russia (scale 1:2 500 000). Levels of Cu, Co and I content in soils were based on our original experimental database and published data of the elements concentration in the cartographic units "topsoil-subsoil". To estimate the ecological and geochemical risk we used threshold concentrations in soils leading to specific diseases in cattle grazing within the particular areas. These concentrations were based on numerous experimental data obtained by different scientific teams (Kovalsky, 1974, 1991; Korobova, 1992; Ermakov, 2015, etc.).

The mapping allowed demonstration of zonal and regional peculiarities in Cu, Co and I status of the soil cover in CFD. The obtained cartographic estimates are comparable with the published averaged results at the oblast level. Comparison with the published medical information on the cases of thyroid disease registered  for the first time in their life for the period from 2013 to 2017 on the level of administrative unit "oblast" showed a significant (p=0.08) inverse (R=-0.47) correlation with our cartographic estimates of soil iodine status weighted for the corresponding oblast's with due regards to their soil structure (numbering 14 in CFD with exception of Bryansk and Oryol oblast'). The two indicated oblast's were considerably affected by radioiodine shock during the Chernobyl accident which contributed to increase of thyroid damage especially in case of its suffering from iodine deficiency.