Regional increase of mean chloride concentration in water due to the application of deicing salt.

The Directive of the European Parliament and of the Council 2000/60/EC: Establishing a Framework for Community Action in the Field of Water Policy, states that it is necessary to consider human activities within a river basin in order to prevent and reduce the spreading of pollutants and to achieve good water status. This paper shows a simple method to estimate the environmental pressure from the deicing of roads as steady state chloride concentration in water. The data processed are presented using GIS. The result showed that the contribution of deicing salt is of importance for the chloride concentration on a regional scale. The increase in chloride concentration is also compared to the background concentration and other sources of chloride within the river basin. Road salt applied by the Swedish National Road Administration (SNRA) accounts for more than half of the total chloride load for the river basin investigated. The method presented may easily be generalised to a national scale for monitoring the environmental effects of deicing salt application.