Forecasting pollutant mobility associated with coastal landfill sites under future climate change scenarios

There are >1,200 historic coastal landfill sites at risk from flooding or erosion in England. Many of these sites were created before detailed waste material logs were kept and prior to the introduction of impermeable liners, that prevent leachate and toxic gas release. Hydrological and hydrodynamic processes form critical pathways through which soluble and sediment-associated contaminants are released and dispersed in the environment, enhancing the risk they pose by increasing their distribution and biological uptake. Climate change will increase contaminant mobility and exposure as the frequency and magnitude of hydrological processes accelerates rates of host material erosion and mobility. This work contrasts contemporary contaminant profiles from three legacy coastal landfill sites in the UK and forecasts how these profiles might change under a range of future climate and intervention scenarios. The results will help decision-makers prioritise sites for protection, which is necessary given the estimated cost to defend or remove legacy landfills is projected to cost hundreds of millions to billions of euros.