Arsenic in the soils of Predkamye of the Republic of Tatarstan

The content of heavy metals and toxic elements in the soils of the Republic of Tatarstan is controlled regularly, but as for the concentration of such haz-ardous element for human health, as arsenic, there is only limited information. In the study the content of total arsenic in one of the regions of the Republic of Tatarstan - Predkamye was tested. The surface and profile element distribution in the main zonal (sod-podzolic, gray forest) and azonal (calcareous, alluvial) soil types of Predkamye were studied. The correlations with basic soil properties were estab-lished. The studies have shown that the arsenic concentration in the samples ranges from 1.8 to 9.5 mg/kg and does not exceed the concentration limit. Significant differences between the levels of arsenic in various types of studied soils were not found. However, element concentration in soils with different value s of particle size distribution (except light clay soils) was significantly different from each other. The smallest element content was observed in the lightest soil of the region - sandy loam. In natural soils not affected by agricultural activities, arsenic had positive correlations with the values of pH (r = 0.61), physical clay (r = 0.67) and silt (r = 0.48) content. In arable soils significant correlations with such properties were not found. The behavior of arsenic in the profile of gray forest and sod-podzolic soils had eluvial-illuvial character. Аrsenic was uniformly distributed in the alluvial soil profiles, with some of its predominance in the surface hori-zon. As in the upper soil layers, in the profile of the investigated soils arsenic content was closely relat-ed to particle size distribution.