The Hungarian sludge spill disaster is just another reminder of the large scale havoc and devastation that industrial sludge impoundments can create. Every few years we read about another one. On April 25, 1998, a tailings dam failure of the Los Frailes lead-zinc mine at Aznalcóllar near Seville, Spain, released 4-5 million cubic meters of toxic tailings slurries and liquid into nearby Río Agrio, a tributary to Río Guadiamar. The slurry wave covered several thousand hectares of farmland, and threatened the Doñana National Park, a UN World Heritage Area.
In the US, the two biggest sludge spills have both been floods of toxic coal ash: 306,000,000 US gallons in Martin County, Kentucky in 2000, and 1.1 billion gallons (4.2 million m³) at the Tennessee Valley Authority‘s Kingston Fossil Plant in Roane County, Tennessee in 2008. (So much for clean coal.) The US is now moving aggressively to improve its supervision of the billions of gallons of coal ash in ponds of varying stability across the US, and to ensure that polluters provide the money needed. The major debate is whether they will be regulated as RCRA SubTitle C (hazardous waste) or SubTitle D (solid waste).
In contrast, Canada is doing little. We have our own coal ash problem, which is getting no attention, but our biggest, most dangerous sludge impoundments are the giant tar sands tailings ponds, which already leak millions of litres into the Athabaska River. And the financial assurance that supposedly guarantees their rehabilitation is short many billions of dollars, according to the Pembina Institute. Their report Toxic Liability: How Albertans could end up paying for oilsands mine reclamation, gives a conservative estimate to clean up the current land area disturbed by mining (more than 68,574 hectares) at up to $15 billion. And that’s without a spill. But I think Pembina got one thing wrong: it won’t be just the Albertans who pay. After all, most of the costs of the Sydney tar ponds (another toxic sludge dump) are being paid by Canadians outside Nova Scotia.