Time-dependent life-cycle assessment of slag landfills with the help of scenario analysis: the example of Cd and Cu

Life-cycle assessment (LCA) studies show that landfills have a large impact on the environment if long-term time horizons are considered. In this paper, the authors use new site-dependent models for slag landfills and transport in soils to estimate the emissions of heavy metals to the groundwater. The results suggest that landfills remain a risk to the environment for very long time periods. The long-term emissions might be valued differently than current emissions, for instance, as a result of a changing background concentration in the environment. A scenario analysis was performed to calculate the future background contamination of the Swiss groundwater with Cd2+ and Cu2+. The environmental impacts of slag disposal were assessed considering this changing background contamination (method applied: Swiss Method of Ecological Scarcity). The impacts of the Cu2+ emissions from the slag landfill to the groundwater were found to be more important than in previous analysis, where the landfill emissions had been assumed to enter the surface water and where the background contamination was assumed to be constant over time.