Lennart Folkeson

Sources and Fate of Water Contaminants in Roads

This chapter gives an overview of sources, transport pathways and targets of road and traffic contaminants. Pollution sources include traffic and cargo, pavement and embankment materials, road equipment, maintenance and operation, and external sources. Heavy metals, hydrocarbons, nutrients, particulates and de-icing salt are among the contaminants having received the greatest attention. Runoff, splash/spray and seepage through the road construction and the soil are major transport routes of pollutants from the road to the environment. During their downward transport through road materials and soils, contaminants in the aqueous phase interact with the solid phase. In saturated media, diffusion, advection and dispersion are the major processes of mass transport. In unsaturated soil, mass transport strongly depends on soil-moisture distribution inside the pores. Sorption/desorption, dissolution/precipitation and ion exchange reactions are the most significant chemical processes governing pollutant transport in soils. Redox conditions and acidity largely regulate heavy-metal mobility. Many heavy metals are more mobile under acidic conditions. Plants close to heavily trafficked roads accumulate traffic pollutants such as heavy metals. Heavy metals, organics, de-icing salt and other toxic substances disturb biological processes in plants, animals, micro-organisms and other biota and may contaminate water bodies and the groundwater. European legislation puts strong demands on the protection of water against pollution. Road operators are responsible for ensuring that the construction and use of roads is not detrimental to the quality of natural waters.

Perceived landscape values and public participation in a road planning process – a case study in Sweden

The European Landscape Convention indicates that assessment of different dimensions that exist in landscapes should be taken into account in planning. In this study, we first investigated ecological, cultural and social values as perceived by the local people in a highway-planning process in Sweden. Next, we explored which factors influenced the local peoples participation in the road-planning process. We used questionnaires, planning documents and the Theory of Planned Behavior to investigate the relations between different factors and local peoples participation in the planning process. The results showed that people presumed the ecological values in the landscape to be adversely affected by the new road, while the social values would remain the same. Landowners had heard of the participatory-process, but few participated. Those who lived within 300 m of the road were more active in the planning process than people living further away. The findings suggest that people living within a few hundred metres of the road should be treated as key stakeholders in the planning process. The involvement of other stakeholders, and when in the public participation process stakeholders should be involved, is also discussed.

Contaminant Sampling and Analysis

This chapter presents a general overview of procedures and methods for sampling and analysis of contaminants in water and soil in the road environment. The chapter concerns the water and seepage in road structures under the influence of traffic loading, and in the adjacent ground extending to the water table where contaminant seepage is of concern. The text gives an introduction to this subject and guides the reader to relevant literature with detailed information about practices of sampling and analysis. The chapter in divided into five main sections: principles of data collection and storage, sampling design, water and soil sampling procedures, and in-situ and laboratory measurements and analyses.