MAGNETIC PROPERTIES OF THE PROFILES OF POLLUTED AND NON-POLLUTED SOILS. A CASE STUDY FROM UKRAINE

Abstract

This report deals with the preliminary study of the magnetic properties of the chernozem depth profiles from polluted and non-polluted areas situated in the Volnovaha–Mariupol agro-soil region in southeast Ukraine. The profiles of soil for study were taken from the chernozem virgin land of the Homutovski steppe and from the nearby polluted area of Mariupol belonging to the Dniprovsko–Donetskij industrial region. The magnetic mineralogy and magnetic properties were examined along the profiles to determine the vertical structure of the non-polluted soil and to find differences caused by pollution. The soil from the non-polluted area is characterized by maghemite and haematite content. Magnetite is present in the topsoil of profiles from the polluted area of Mariupol. Blocking temperatures increase with depth in all profiles, becoming close to the temperature characteristic for haematite. Hysteresis parameters show that the deep soil is characterized by higher coercivity and coercivity of remanence values and lower saturation isothermal remanent magnetization and saturation magnetization values than the respective parameters in the topsoil. The grain size of magnetic minerals also changes with depth, becoming larger for deeper horizons. The surface values of susceptibility, saturation magnetization, saturation isothermal remanent magnetization and anhysteretic remanent magnetization for the polluted profiles from Mariupol show enhancement in relation to the values for the Homutowski steppe as a result of contamination by magnetite and haematite. However, starting from a depth of approximately 80–100 cm, the magnetic parameters approach the same values. This suggests that in deep horizons a lithogenic contribution prevails, similar for both areas.