Historically it was common practice to dispose of landfill waste in low-lying estuarine and coastal areas where land had limited value due to the risk of it flooding. Globally, there are hundreds of thousands of historic landfills in coastal areas. Historic landfills are frequently unlined with no leachate management and inadequate records of the waste they contain, which means there is a very limited understanding of the environmental risk posed if the waste erodes into estuarine or coastal waters.
In a WIREs Water paper, Brand and co-workers review what is known about historic landfills in England and identifies there are over 1200 historic landfills around the English coast that have a 0.5% annual probability of being flooded with seawater. Over one-third of these historic coastal landfills are in close proximity to designated environmental sites, e.g. Sites of Special Scientific Interest, and half of them are in or near to areas influencing bathing water quality.
Some historic coastal landfills have already started to erode and release waste into estuarine and coastal waters, and with the anticipated effects of climate change, e.g. sea level rise and more intensive storms, erosion events are likely to become more frequent. If no preventative action is taken, 10% of England’s historic coastal landfills may start eroding by the year 2055.
Strategies to mitigate the risk of contaminant release from historic landfills such as excavation and relocation or incineration of waste would be prohibitively expensive for many countries. Therefore, it will be necessary to identify which sites pose the greatest pollution risk in order that resources can be prioritized, and to develop alternative management strategies based on site specific risk.
Brand and co-workers highlight that before such management strategies are implemented there remain many unknowns to be addressed including the extent of legacy pollution in coastal sediments, impacts of saline flooding on contaminant release and the nature, behavior and environmental impact of solid waste release in the coastal zone.
If you would like to see whether there are historic landfill sites near to you, maps can be found on Queen Mary University of London’s website: www.geog.qmul.ac.uk/research/historiclandfill/
Kindly contributed by Dr James H. Brand.