Impact of climate change on contaminated land containment systems.

Sinead Smith, Cambridge University
Geotechnical Engineering Group


Contaminated land remediation is a major development issue in the UK. In-situ remediation techniques, including containment methods such as cover systems and stabilisation/solidification (S/S) remediation, are increasingly used to avoid off-site disposal of contaminated soil. However the retention of contaminants on site leads to concerns over long-term performance. The management of contaminated land in the UK is based on risk assessment using current environmental conditions. Climate change is a major issue that threats the long-term integrity and performance of many infrastructure systems including remediated sites. Certain future climate change scenarios could increase the risk of remediation failure. Limited literature studies have considered the impacts of climate change on contaminated land containment systems, although investigations in different parts of the world demonstrate that climatic factors have a significant influence on those systems. The literature review showed that certain climatic factors such as wet-dry and freeze-thaw cycles have a significant detrimental effect on containment systems

In this work, the object was to experimentally investigate the effect of a number of climate change scenarios on the physical, mechanical and chemical performance of a contaminated soil, S/S remediated soils and cover systems, in order to determined the most critical parameters in terms of the soils, contaminants and climate scenarios and the potential magnitude of the impacts. These findings, combined with others from the literature, can then be used to assess the need for any technical adaptation and any potential change in the management strategies of contaminated land and the design of containment systems. Climate scenarios were designed to represent the years 2050 and 2080 and were imposed for two years in real time. In addition, numerical modelling was undertaken to predict the performance of a cover system to 2080. As climate change is a long term phenomenon, the effects of ageing were also investigated. The physical, mechanical, microstructural and chemical properties of each soil system were monitored during the two-year climate scenarios. The results showed that certain climate change scenarios would increase contaminant mobility in contaminated soil and would have adverse effects on the performance of containment systems. Intermittent summer rainfall and flooding in winter were found to be the most damaging scenarios. The modelling work was able to simulate these impacts. The adaptation strategies proposed include frequent risk assessments for contaminated sites as the climate changes and more stringent design criteria for containment systems to allow for the potential damaging impacts of climate change.