In the heart of the Canadian Shield, north west of Toronto, sits the mining and industrial city of Sudbury, Ontario. Sudbury is well-known for the extent of the land pollution around the city. This land pollution is a by-product of the mining and smelting that are the economic heart of the region.
Sudbury is the middle of a geological feature known as the Sudbury basin, which is believed to be a 1.85 billion year old impact crater. The basin is the source of highly profitable amounts of many minerals, in particular copper and nickel, along with smaller, but commercially-viable, amounts of cobalt, gold, silver and platinum, along with others. The source ores contain large amounts of sulphur as well, which was released as part of the smelting process. For decades, Sudbury had an extensive acid rain problem which seriously damaged much of the surrounding ecology.
A persistent urban legend about Sudbury is that the Apollo astronauts trained there because the barren terrain resembled the surface of the moon. While astronauts did train there, it was because of a geological formation called shattercones, which they expected to find on the lunar surface. The local ecology was stunted, perhaps even devastated, but it wasn’t actually destroyed.
Erosion had stripped the soils, and what soils that were left were contaminated with high levels of heavy metals. They were highly acidic as well, with pH values from 2.0 to 4.5. Acid-tolerant trees like birch still grew, as did some other types of plants, though growth was often stunted.
In the early 1970s, INCO Mining built the Superstack, the tallest smokestack in the world, and the second highest structure in Canada. The Superstack dispersed the sulphur particulates farther away, and over a wider area, reducing the level of acid rain in the Sudbury area. Then people went to work on recovering the land from the pollution.
The first step was soil improvement. Lime was used in many areas to reduce soil pH, and what soil remained was seeded with hardy grass to prevent it from blowing away. In areas where there was still extant vegetation, the soils were likewise treated with lime. In treated areas recovery was rapid, though the lack of vital nutrients became critical after the first year. Treatment was initiated to reduce heavy metal concentrations as well.
Reforestation followed in some areas, with trees like sugar maple and red oak planted to provide colour. The trees were planted in a way meant to encourage soil retention and permit the trees to seed and spread. Some high-profile animal species have been reintroduced, like the peregrine falcon.
From an aesthetic and social standpoint, the reclamation has been a success so far. Certainly Sudbury looks better, and residents feel that it is a better place to live. However, less than 30% of the affected land has received any sort of remediation so far, mostly all in high-visibility areas like traffic corridors and residential areas. From a scientific standpoint, the work really has only just begun.
Much more needs to be done. None of the areas around Sudbury are truly functioning ecologies, though a foundation has been laid in the reclaimed areas. More areas need to be reclaimed, and more animal species reintroduced. Heavy metal concentrations are still high, and need to be lowered to an acceptable level.
Even this partial reclamation of the blasted land around Sudbury shows that the areas we destroy, with enough work and time, we can eventually rehabilitate. For all the human-blighted areas on the planet, all the places afflicted with land pollution, or with poisoned waters, this is good news.