Society needs to maintain road safety and accessibility of the road network at acceptable levels during the winter season. The use of sodium chloride as de-icing medium can lead to several impacts on human health and nature, as for instance damage to ground water resources and vegetation. The question of whether the political goals of accessibility, transport quality and safety can be fulfilled at the same time as the goal of a good environment is fulfilled, must be seen as a delicate matter of conflicting interests. In order to be able to evaluate countermeasures taken against the undesired impacts, the system needs to be monitored with indicators at several levels within the system. An integrated environmental assessment framework that is suitable for such evaluations is the DPSIR-approach. It is for instance used by the Swedish Environmental Protection Agency for the follow-up of the national environmental quality objectives in Sweden. According to this framework there is a chain of causal links, from the societal need for transportation as driving force (D) of the system, over the pressure (P) of roadside exposure to salt, to an altered state (S) of the roadside environment leading to different kinds of impact (I), which may require some kind of societal response (R). In most cases it is important to find useful indicators as early in the system as possible, especially when the environmental effect is delayed in time, as for instance regarding contamination of ground water resources. In that case an early warning could be reached. By assigning adequate indicators to the different levels of the DPSIR model, the road keeper will not only strengthen his scientific understanding of the ecological effects, but also increase his possibilities to take appropriate measures to improve the sustainability of the system and finally increase the knowledge of the environmental utility of the strategic actions taken. (Author/publisher)
Abstract