Sulphate contamination, pH and conductivity of forest soils in two neighbouring mountains with different pollution in Slovakia from 1989 to 2013

Abstract

The Štiavnické vrchy Mts. were strongly affected by pollution mostly from an aluminium plant in 1953–1989. This paper compares contamination of soils between Štiavnické vrchy Mts. and the neighbouring little polluted Kremnické vrchy Mts. from results of a 25-year study. After a decrease of emissions in Slovakia at the beginning of the 1990s the sulphate sulphur content, acidity and conductivity of soil water have decreased only on the surface and at a depth of 0.10 m at the study site in the Štiavnické vrchy Mts. At the depth 0.25 m the increase of sulphurization (23.68 kg/ha S-SO₄^2– per year) and acidity (pH 4.92) was observed. During the research, the total sulphate sulphur influx to this soil depth was 568.3 kg/ha. The average sulphur input in the study areas of the Kremnické vrchy Mts. decreased with depth: from 18.48 kg/ha/year in the surface humus to 6.85 kg/ha/year at a depth of 0.25 m. The maximum sulphur influx at the open plot was 24.06 kg/ha/year and in total 553.34 kg S-SO₄^2–. A small increase of acidity at soil depths of 0.25 m at some sites was observed also in the Kremnické vrchy Mts. Regression analysis revealed a statistically significant influence of sulphate sulphur content in the atmospheric precipitation on the sulphur amount in the soil water. A significant correlation was also observed between the precipitation amount and the sulphur content in soil water. Data from monitoring revealed significant differences between the sulphur amounts at depths of 0.10 m and 0.25 m in these study areas.