Wpływ wód odciekowych z odpadów wydobywczych na poziom zanieczyszczenia gleby leśnej oraz możliwości jej dalszego użytkowania przez gospodarkę leśną

Forestry management in anthropo−transformed habitats is characterized by a very high risk. The formation of waste as well as flooding of tree stands by salty water from different sources of mining and processing of coal is an important issue on the industrial areas. The introduction of the pollution load in the form of saline water leads to increased soil salinity, which can damage or cause the dieback of individual trees, tree stands and whole forest ecosystems. The aim of the research was to (i) analyze the changes in forest soils on the area flooded by water leaked from the waste reservoir, (ii) assess the possibility of this soil self−purification from chlorides and sulfates and (iii) estimate the possibility of reclamation of this land for forestry purposes. The study was conducted in Katowice Forest District (southern Poland). Soil samples for physico−chemical analysis were collected in 2015. The results of chemical analyzes of surface soil layers made in 2013 and 2014 were also used. The content of chlorides and sulphates in the soil was used as one of the key indicators to assess the level of soil salinity. In the year of the damage occurrence, in surface horizons it significantly exceeded the threshold value, but declined in subsequent years to a level below this value even in the area of the greatest damage. However, our analysis indicate an accumulation of chlorides and sulphates in the soil at a depth of 100−120 cm, as well as the accumulation of sodium cations. This demonstrates the difficulties with the self−purification of soil or continuous supply of pollutants from the waste reservoir. Currently, surface soil horizons meet the criteria of not−salinized soils, which does not indicate a need for change in land use. After the surface preparation and technical work used in forestry practice, the damaged area can be designed for the reintroduction of forest trees.