Soil indicators used in road environmental impact assessments

This study has been aimed at proposing a set of specific indicators for the impact assessment of road soils in contact with pavement layers made of industrial byproducts. Two French roads having undergone a 20-year service cycle, one located on a silty surrounding soil and the other on a sandy soil, is studied herein. The pollutant fluxes released by road layers are first determined with respect to a functional unit, according to LCIA protocol. Next, beginning with impact study principles and a local soil state characterization, a reference soil assessment is also performed. Trends in pollutant variations, expressed using road-specific indicators as a function of soil depth, are analyzed and any unexpected maximum values highlighted. A chemical species analysis is then proposed in each local context with respect to the soil type. The capacity of the set of proposed indicators to assess the road's environmental impacts on soils for other sites is discussed in the paper's final section.