Geogenic and Pedogenic Inheritance of Arsenic, Antimony, Selenium and Tellurium in Poorly Developed and Metamorphic Soils

The content of arsenic, antimony, selenium and tellurium in soils from a territory with natural and man-caused load, located in the range of the Old Quaternary proluvial plume in the northeastern part of the Sofia valley, was studied. The contents have been determined by LA-ICP-MS, together with those of more than 45 chemical elements, for the purpose of future remediation and study of the impact of natural and man-made factors on the geochemical relationships of the elements in the specific soil environment. The studied soil types are Regosols and Cambisols, most of which have been changed and classified as Technosols (IUSS Working Group WRB, 2015, Teoharov et al., 2019, Stoykova, 2021) under the influence of industrial waste from the former Kremikovtzi metallurgical plant. Very high contents of the groups of elements Te - Se and As - Sb have been established, which are inherited from the soil - forming rocks with predominant, respectively syenite or ore material. The content of arsenic in Technosols is on average 4 times higher than the maximum permissible concentration of metalloid in industrial soils, and the arsenic in the control profile of Cambisols exceeds 1.5 times the norm for the maximum permissible concentration for arable land. The processes of overwetting, acidification and microbiological activity are the factors that influence the redistribution of the four elements in the soil environment. Contamination with agglomeration dust leads to the accumulation of antimony in the spolic horizon, where it is associated with a number of heavy metals. Its more metallic character is reflected in the statistically significant high positive correlation with iron - r (Sb-Fe) = 0.85, which shows only this element.