Soil buffering of landscapes of Donetsk region before pollution by heavy metals

Abstract

Goal. To determine the qualitative and quan­titative characteristics of the buffering of soils of the Donetsk region to heavy metals (HM). Methods. The research was conducted in the Donetsk region in 2016 – 2018. Methods: field, laboratory, computational and mathematical statistics. Results. The properties of soils that determine their buffering to HM were studied. The soils of the Donetsk region are mostly neutral. For the main part of them (92.8%) the humus content varies from high to very high, which forms a fairly high buffering to HM contamination (average humus content in the region is 3.8 – 4.6% ). Assessment of buffering to HM according to V. Iliin scale showed that typical medium and low-humus chernozems (which are most common in the region) had 37 points and were characterized by increased buffering. Crushed and solonetzic chernozems had 27.5 and 30 points, respectively, which indicated to average buffering. It was experimentally found out that in the zone of influence of waste heaps of coal mining the content of mobile HM also depended on the buffering capacity of the soil. Crushed chernozems in comparison with typical medium-humus ones contain almost twice as much lead and cadmium in mobile form. A significant share of pH influence on the formation of buffering was revealed: for crushed chernozem, it was the same as the share of physical clay and it was about 36%. The share of humus and one and a half oxides for the studied soil types was in the range of 11.7 – 13.5% and 13.3 – 18.9%, respectively. When moving away from the source of pollution, the content of HM decreased regardless of soil type. Conclusions. Buffering of soils of the Donetsk region to heavy metals is estimated from 27.5 to 37 points. Common chernozems are characterized by increased buffering, crushed, and solonetzic chernozems — by the medium. The obtained results made it possible to assess the risks of contamination of plant products with HM and predict the cultivation of environmentally friendly products in regions of high man-made pressure.