Role of Gravitational Processes in the Migration of Heavy Metals in Soils of the Priolkhonye Mountain-Steppe Landscapes, Lake Baikal: Methodology of Research

Abstract

The study object of this work is the soils of the Priolkhonye mountain-steppe landscapes. This research is performed at the Priolkhonye test site. Annual monitoring for exogenous geological process activity is conducted there. This research aims to study the influence of gravitational geological processes (landslides) on the migration of heavy metals, which are introduced into soil as a result of human agricultural activity. A methodology for the geoecological monitoring of soils based on an assessment of their contamination level by anthropogenic heavy metals, and a transfer mechanism throughout whole migration path (field–landslide–coast) is proposed. The following steps were taken to solve this problem: isolating a fine-grained fraction (<100 μm); determining the Hg, Cd, Pb, and Cu concentrations using wavelength dispersive X-ray fluorescence and atomic absorption spectroscopies, as well as total organic carbon (TOC) content using UV-Vis spectrophotometry; computing various geochemical indices; and describing the migration path of these heavy metals and TOC. The monitoring results showed that these pollutants migrate to the coastal zone as a result of landslides activation. The soil contamination level is increased which can cause negative toxic effects in coastal ecosystems, and could rise to a dangerous level for humans. Thus, the observed changes in the indices and TOC values allow us to assess the geoecological state of the study area; namely, the periods of landslide activity and the supply of these pollutants to the coastal zone.