Increasing concentration of deicing salt in soils in the Bavarian Forest National Park

Abstract

The negative effects of applying deicing salts to ecosystems are well documented for many countries. Most chemical transport from roads occurs in stormwater runoff through or over soil. Runoff pollutants alter soil chemistry, may be absorbed by plants and affect stream ecosystems, where they are dispersed and diluted over considerable distances. There was little detailed knowledge of the effects of deicing salts on ecosystems in the Bavarian Forest NP until 2011, when nine permanent sites were established along the main road in the eastern part of the NP. Soil samples were collected from four of these permanent sites in 2012, 2015 and 2018 and analysed by a certified laboratory. The results of soil chemical analysis were used to compare sites and samples from years 2012, 2015 and 2018. Our research confirmed the increasing concentrations of Na+ and Cl− ions in ecosystems in the Bavarian Forest NP. The highest concentrations of Na+ and Cl− ions were recorded in samples from sites # 4 and 5, which are located only several meters from the bank of the Grosse Ohe River. These concentrations were more than ten times higher than in samples from sites where deicing salt was not used. Amphibians, water insects and other extremely sensitive species and habitats occur in this part of the Bavarian Forest NP and are probably suffering from increasing salinity of their habitats. More research focusing on a better understanding of the spread of deicing salt in the ecosystem together with improving road maintenance technologies are need in order to improve the situation.