Effect of Chlorides from Chemical De-Icing Agents on Soil Contamination Depending on the Distance from Road and its Effects on Living Organisms

The article deals with the contamination of soil in the vicinity of the D1 motorway caused by the application of chemical de-icing agents in winter. In the selected area, during a period of one year (from October 2017 to October 2018), soil samples were regularly collected once a month at five different distances from the road. Chloride concentrations in aqueous extracts of the soil were monitored and the degree of toxicity was established for the selected living organisms. The resulting chloride load was evaluated with respect to the precipitation activity and the amount of de-icing salt applied in the area. The highest concentrations of chlorides were found at a distance of 2 m from the road. At the distance of 20 m from the road, the concentration of chlorides in the soil was approaching the chloride concentration found in the referential background set for the selected locality. The concentrations of chlorides at the first three measured distances from the road corresponded to the quantity of de-icing salt applied and the precipitation activity recorded during the relevant months. The maximum concentrations were reached in April 2018. Ecotoxicological testing of aqueous extracts of soil did not confirm any significant toxicity to the selected living organisms. From the tested organisms, the white mustard was identified to be the most sensitive to this type of toxicity; the increased toxicity was observed only for aqueous extracts of soil samples collected at distances d_I (0 m) and d_II (1 m), thus, it could have been related to the increased concentration of chlorides during the relevant period.