4,000 old landfill sites are at risk of flooding, some containing hazardous waste
March 9th 2016
Scientists at the British Geological Survey and Queen Mary College, University of London, are warning that the UK faces the risk of pollutants leaking out from the large number of historic landfill sites that pre-date EU waste regulations introduced in the 1990s. It is estimated that there are 21,027 historic landfills in the UK, with 1,264 sites situated in estuaries and coastal areas at risk of erosion, and a further 2,946 sites located on floodplains. Current regulations require landfills to be sealed with a protective lining, thereby insulating the waste from the surrounding land and watercourses. However, older landfill sites, some of which date from the late nineteenth century, are unlikely to have such protection, leaving them at risk of flooding from coastal erosion or severe weather such as heavy rain and storm surges.
A report produced by CIRIA in 2012  says that the number of historic landfills is likely to be an under-estimate owing to a large number of unrecorded illegal sites. In addition, as the 21,000 historic landfills were developed when there were no legal requirements for their management or monitoring, records of the waste that was deposited in them can be incomplete or non-existent. Speaking to The Independent, Dr Daren Gooddy, an environmental chemist at the British Geological Survey, said he was particularly concerned about those historic landfills that are located in areas with a high flood risk and that contain dangerous substances such as hazardous chemicals and asbestos. He calculated that there are 1,655 such sites. “While it’s hard to say for sure, I would suggest that many of these legacy sites are vulnerable to flooding,” he said. “Even when flooding does not occur these sites leach out contaminated waste, which generally gets transported towards the nearest river.”
Dr Kate Spencer, environmental chemist at Queen Mary College, University of London, has been carrying out research to assess the potential impact of flooding and coastal erosion on historic landfill sites on low-lying coastal areas. Her research team is working with the Environment Agency to create a vulnerability ranking which will help to identify those sites that present the greatest danger, based on the risk of flooding and the contents of the landfill. “The work we’ve done in the South-East suggests that there has already been widespread pollution from historic landfills,” she said. “At one site we actually found a blue poison bottle from a pharmacist that had a skull and crossbones on it, with a stopper and liquid inside.”
In a blog post for Friends of the Earth, Guy Shrubsole reports on a visit in 2015 to a leaking landfill at Tilbury on the Thames estuary. Walking along the coast, he discovered that a two kilometre stretch of the Thames foreshore was filled with waste. “But this wasn’t just rubbish deposited by the waters of the Thames as it sweeps through London,” he says. “It was clearly eroding out of the sandy banks next to the shoreline, lapped by high tides. The remains of a former sea wall, derelict and ineffective, could still be seen below the high-water mark. It was providing no defence at all to the hungry estuary, which had chewed away at the land to reveal layers and layers of landfilled refuse.”
Guy Shrubsole says that maps produced by the Environment Agency show there are several historic landfills in the Tilbury area, but tidal defences at such sites are not maintained, leaving them with no protection from tidal surges and rising sea levels. “No one is taking any responsibility for the huge amounts of waste that is now very clearly leaking out of the old Tilbury landfills,” he says. “And this is just one example. If, as the research suggests, there are thousands of old landfills at risk of leaking their wastes into watercourses and the sea across the UK, then this is a massive, ticking time bomb.”
Dr Kate Spencer said that historic landfill sites “date back to a time when there were no protective linings, no regulation about what went in and little in the way of records about the contents. Many are on coastlines highly vulnerable to coastal erosion, storm surges and flooding and the big concern is that they will become even more vulnerable as climate change makes storms more frequent and intense.”
As we reported in a previous news item, scientists from the British Geological Survey have carried out research into river pollution from historic landfill sites. The focus of their investigation was Port Meadow which lies on the banks of the River Thames, north-west of Oxford, where 11 such sites are located. Their research, based on ammonium sampling, concluded that there are potentially thousands of historic landfill sites that are currently leaching large amounts of nitrogen into major rivers, which can damage water quality and trigger nutrient pollution. As climate change makes flooding more likely, leakages from landfills located on floodplains are also likely to increase.
 Cooper, N., Bower, G,. Tyson, R., Flikweert, J., Rayner, S., Hallas, A.: Guidance on the Management of Landfill Sites and Land Contamination on Eroding or Low-Lying Coastlines (C718). CIRIA, 2012.