THE TRANSFORMATION AND RECOVERY OF A DEGRADED NATURAL ENVIRONMENT: THE CASE OF THE SUDBURYAREA, ONTARIO, CANADA
Received: 2024-10-15 Revised: 2024-11-15 ; Accepted: 2024-12-05
Published Online: 2024-12-31
Abstract
The city of Greater Sudbury, once a symbol of environmental degradation due to extensive mining activities, has transformed into a modern green city distinguished for its sustainable practices and fertile surroundings. This article explores the remarkable ecological recovery achieved over three decades, beginning in the 1960s, after more than 60 years of environmental devastation caused by sulfur emissions from nickel and copper extraction. These emissions led to widespread soil acidification, severe erosion, and barren landscapes that prevented vegetation from thriving. The recovery was made possible through a collaborative effort involving municipal, provincial, and federal governments, researchers from Laurentian University, and the region's two largest mining companies. This study examines the policies, scientific innovations, and community initiatives that collectively facilitated Sudbury’s transformation into an environmentally responsible city. It highlights how strategic reforestation, soil remediation, and sustainable industry practices revitalized the local ecosystem, offering a model for urban environmental restoration worldwide.
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1. INTRODUCTION
The Sudbury region is renowned for its vast nickel reserves (50 million tonnes), which are among the most significant mineral deposits in the world. In addition to nickel, the region boasts several deposits with high concentrations of copper. Discovered in 1880, these ore deposits are distributed within a 150 km radius of the elliptical Sudbury Basin (Winterhalder, 1996). Beginning in 1886, mining operations gradually established themselves as the region's principal industry, overtaking logging. A first open-cast smelter was founded in 1888, soon followed by many others. Their environmental impact was catastrophic, creating 10,000 hectares of barren land.
Until the 1950s, Sudbury was recognized as the world capital of nickel. However, environmental concerns were largely ignored during this period (Boerchers et al., 2016). Awareness of environmental problems emerged only in the 1970s, leading to the enactment of stricter environmental standards (Lauterbach et al., 1995). More recently, the adoption of sustainable development principles has driven the creation of major intervention programs and management strategies, making it imperative to address environmental degradation (Peters, 1995).
The region embarked on a large-scale environmental requalification project, seeking to balance economic development with higher environmental standards. For example, the City Council’s Advisory Panel on Regreening (VETAC) was established in 1973. Its mandate is to work towards the recovery of self-sustaining, indigenous terrestrial and aquatic ecosystems in Greater Sudbury through the City’s Regreening Program. VETAC also provides opportunities for community participation, encouraging environmental improvement efforts at home, in neighborhoods, and on public lands (VETAC, 2024).
Primarily, efforts were focused on mitigating sulfur dioxide emissions and industrial pollution. To reduce sulfur emissions, the construction of the Superstack was undertaken. Built by Inco Limited (later acquired by Vale) at an estimated cost of $25 million, the Superstack stands at a height of 381 meters, making it the second-tallest freestanding chimney in the world (Ogilvie, 2003). In addition, reforestation and regeneration efforts were launched, significantly contributing to the requalification of the landscape (Lautenbach, 1995).
2. ECONOMIC INTERESTSVERSUS ENVIRONMENTALPROTECTION
The relationship between economic growth and environmental protection is one of the most pressing issues in modern economics. Currently, economic growth often occurs under conditions of significant environmental stress (Figueroa, 2013). Energy consumption can drive economic growth by enhancing productivity but simultaneously exacerbate environmental damage through increased pollutant emissions (Tiba & Omri, 2017). On one hand, countries strive to boost economic growth to improve the living standards of their populations, while on the other hand, environmental challenges become more complex due to the excessive use of natural resources (Ghafoor-Awan, 2013).
Fortunately, over the past few decades, advancements in technology driven by research and development (R&D) have facilitated reductions in environmental pollution (Groth & Ricci, 2011). The 1992 Rio de Janeiro Summit brought new ideas and optimism, reinforcing and reaffirming the principles outlined in the Declaration of the United Nations Conference on the Human Environment, adopted in Stockholm on June 16, 1972. The Rio Summit resulted in the adoption of several significant environmental treaties, which encouraged industries to innovate and invest in R&D to address environmental concerns. These efforts led to substantial improvements in technology management and a consequent reduction in pollution(United Nations, 1993).
The Kyoto Protocol of 1997 marked another pivotal step, aiming to reduce the emission of greenhouse gases contributing to global warming (Basseti, 2022). Another key agreement, the Paris Agreement of 2016, focuses on helping countries adapt to the effects of climate change and mobilizing adequate financial resources for mitigation and adaptation efforts (Falkner, 2016).
An early attempt to mine copper in the Sudbury region was made in 1770. In 1856, provincial land surveyor Mr. Salter reported a strong magnetic influence in the area. This magnetic variation was later studied by Alexander Murray of the Geological Survey of Canada. However, the idea of exploiting the region's copper and nickel deposits only began to take shape with the arrival of the railroad. At that time, the potential use of nickel was not yet understood, and it was regarded as little more than an impurity in the more valuable copper ore (Burron, 2022).
Copper has been known since antiquity, while nickel was only discovered in 1880. Copper is one of the ancient metals, along with gold, silver, lead, tin, iron, and mercury, which were the only known metals until the 13th century. Since 1820, copper has been used as an electrical conductor (Olsen, 2020).
Around 1856, surveyors like W.A. Slater and Alexander Murray, while running lines between the fifth and eighth miles of the meridian, discovered significant local magnetic attraction, with the compass needle deviating between four to fourteen degrees westward. They reported their findings to the government, but their observations were ignored (Royal Ontario Nickel Commission, 1917, pp. 20-28).
When Canada was established as a country in 1867, the first Prime Minister, Sir John A. Macdonald, envisioned expanding the nation westward. Initially comprising only four provinces (Ontario, Quebec, New Brunswick, and Nova Scotia), Canada sought to include British Columbia. In 1870, Macdonald initiated negotiations with the Colony of British Columbia, offering a transcontinental railway linking it to eastern provinces within ten years (Riendeau, 2007).
The construction of the transcontinental railroad in 1880 led to the discovery of large deposits of copper-nickel sulfides in the Sudbury Basin. In 1883, a blacksmith named Thomas Flanagan was the first to recognize the commercial potential of these mineral deposits. Subsequently, other prospectors, including Thomas Frood, Francis Crean, Henry Totten, and James Stobie, arrived and eventually had mines named after them (Joyce & Poulin, 2022). The Canadian Copper Company, founded by Samuel J. Ritchie of Ohio, became the first truly successful mining operation in the region.
Processing the copper found in Sudbury posed challenges because it was bonded with nickel and sulfur (Peck, 2008). Although nickel had been discovered earlier, its uses were not yet well understood. Nickel was first isolated and classified as an element in 1751 by Axel Fredrik Cronstedt, who initially mistook the ore for copper while working in the cobalt mines of Los, Hälsingland, Sweden (Sigel et al., 2008).
Nickel proved to be an important metal, particularly as an alloying element. It played a crucial role in the manufacture of weapons during World War I and World War II, including guns, tanks, and anti-aircraft ordnance, which required nickel alloys for strength and durability (GMR Gold, 2008). Today, approximately two-thirds of global nickel production is used to produce stainless steel, enhancing properties such as formability, weldability, ductility, and corrosion resistance. Nickel's contribution makes stainless steel a versatile and widely used material (The Nickel Institute, 2017).
About 68% of global nickel production is used in stainless steel, with 10% in nickel- and copper-based alloys, 9% in plating, 7% in alloy steels, 3% in foundries, and 4% in other applications, including rechargeable batteries for electric vehicles (EVs) The Nickel Institute(The Nickel Institute, 2019; Treadgold, 2019). Nickel is also widely used in coin production. Copper- nickel alloy coins are resistant to tarnish, have unique electronic signatures for fraud prevention in vending machines, and exhibit antimicrobial properties, making them more sanitary than coins made from other materials (Copper Development Association Inc., 2006). By 1900, advancements in nickel applications and refining technologies made nickel mining increasingly profitable. In 1910, the Sudbury Basin was producing 80% of the world’s nickel (Burron, 2022).
The Sudbury Basin is a significant geological structure located in Northern Canada (Waldon et al., 2020). According to Davis (2008), this basin was formed by the impact of an asteroid approximately 1.8 billion years ago during the Paleoproterozoic era (Fig. 1).
The Sudbury Basin is economically significant because it contains magma filled with minerals essential to industry, such as nickel, copper, gold, and platinum group metals. This magma was produced during the meteorite impact that occurred 1.8 billion years ago. These magmatic deposits formed as metals combined with sulfur in molten rock. As Ian Burron states, this "trillion-dollar mining district was forged in the fiery impact of a planet-killing asteroid" (Burron, 2022).
By 2020, the Sudbury Basin had become the richest mining district in North America and ranked among the top ten globally, elevating the city of Greater Sudbury into a major mining industry hub. To date, the mines of Sudbury have produced over $250 billion worth of metals, including 8 million tonnes of copper and nickel, 3,200 tonnes of silver, 300 tonnes of platinum, and 100 tonnes of gold. It is estimated that the Sudbury Basin’s ore reserves could sustain mining operations for another 100 years (Burron, 2022).
The nickel mined from the Sudbury Basin contained sulfur, and obtaining completely pure nickel required the construction of huge roasting beds. These beds were fed with wood from Sudbury's forests and allowed to burn for nearly four months. The resulting emissions of sulfur dioxide and particulate metals caused significant environmental damage, resulting in the loss of soil and vegetation over tens of thousands of hectares and acidifying the region's soil (Gunn, 1995). It is estimated that approximately 100 billion tons of sulfur dioxide have been released into the atmosphere since 1915 (Mykytczuk, 2021).
Soil degradation, including erosion of outcrops, can be attributed to extensive logging and the proximity of smelters (Fig. 2). Analysis of the various impacts of mining activities on natural landscapes highlights degradation in terms of discoloration and denudation.
The dark coloration of many outcrops in Sudbury inevitably draws attention when walking through the area. Over the past century, these outcrops have been exposed to sulfurous fumes, accumulations of industrial dust containing high levels of metals (copper, nickel, aluminum, cobalt, etc.), intense heat from forest fires, and harsh weather conditions. The combination of these factors, along with the physicochemical reactions of exposed surfaces, explains this discoloration (Étongué-Mayer, Raoul et al., 1999).
Thin and fragile, the soils of the region have suffered extensively from erosion. The soils covering the bedrock and the organic soils in depressions, which previously supported vegetation, were particularly affected by fumes from open-air smelters and conventional foundries (Winterhalder, 1995). Logging practices, especially clearcutting, and the destruction of ground litter by fires left the soil vulnerable to heavy rains and runoff, significantly accelerating erosion.
In areas where glacial sediments were relatively thick, the materials displayed some stability despite the effects of freezing and thawing. However, slopes were particularly susceptible to runoff water, which caused deep cuts in certain areas. Material from these slopes was displaced through sliding or creeping. Debris eroded from the slopes gradually accumulated in the bottoms of drained or undrained valleys and, in some cases, filled stream and river beds (Étongué-Mayer, Raoul et al., 1999).
Pollen analyses used to reconstruct the evolution of Canadian vegetation indicate that the Sudbury region experienced a mixture of boreal and temperate forests over the past two millennia (Ritchie, 1988). The studies by Amiro and Courtin (2011), as well as those by Pitblado and Amiro (1982), describe not only the current floristic composition of the region but also its spatial distribution. These findings suggest that the extent of denudation depends on topography (slope gradient) and soil pH (≤ 4).
In degraded areas with moderate to steep slopes, the floral composition includes species such as red maple (Acer rubrum), red oak (Quercus borealis), American elm (Ulmus americana), and small deciduous species like blue elderberry (Sambucus cerulea Raf.), black elderberry (Sambucus pubens), and boreal viburnum (Viburnum cassinoides). Moss (Pohlia nutans) and tufted hairgrass (Deschampsia caespitosa) grow both on slopes and in certain depressions. Plant formations dominated by red maple (Acer rubrum) and white birch (Betula papyrifera Marsh.) have been particularly affected by acid precipitation, which has significantly reduced their distribution area over time.
The oldest regional human activity with the most severe environmental effects is logging. In the 1870s, logging employed more than 11,000 people (Winterhalder, 1995). The large- scale use of clear-cutting techniques targeted primary forest species such as red pine (Pinus resinosa Ait.), white pine (Pinus strobus), jack pine (Pinus banksiana), black spruce (Picea mariana), white spruce (Picea glauca), and white cedar (Thuja occidentalis). This deforestation not only contributed to the reconstruction of Chicago after the great fire of 1871 and supplied wood for open-cast smelters but also led to widespread denudation and soil erosion. Between 1888 and 1929, the eleven open-cast foundries in the region consumed more than 3.3 million cubic meters of wood.
The first scientific observations on the chemical quality of water in lakes and swamps in the Sudbury area date back to the 1960s (, 1960). It was noted that several lakes were experiencing high acidity, accompanied by the decline or even disappearance of many fish species (Beamish, 1976). These studies were supported by paleo-limnological and geochemical analyses that measured environmental changes over time (Dixit et al., 1995; Smol, 1992).
Analyses of sediment cores obtained from various stratigraphic sequences indicated the presence of geochemical markers, plant pigments, and fossils of aquatic origin (Smol and Glew, 1992). Cores extracted from Clearwater Lake and dated using lead-210 methods revealed environmental data spanning 200 years. Geochemical studies of these cores for the period between 1920 and 1970 showed an increase in the concentrations of aluminum, nickel, and acidity (Dixit et al., 1995). According to these analyses, 1970 marked a stabilization in geochemical changes, while the years 1980 to 1984 showed a significant decline in nickel and aluminum concentrations, as well as an improvement in pH levels. These improvements coincided with the implementation of various pollution control measures.
On a historical scale, the analyses demonstrate that during the pre-industrial period and up to the 1930s, none of the lakes in the region had a pH lower than 5. However, by 1970, 13.6% of lakes located within a 100 km radius of industrial activities had a pH ≤ 5. The lakes nearest to the smelters and those in the northeast-southwest region exhibited the highest levels of acidity (Dixit et al., 1995).
Environmental problems arising from resource exploitation in the Sudbury region stem from the timber industry, forestry practices, the mining sector and its open-air smelters, sulfur emissions, and air pollution, along with the degradation of water bodies and plant cover. It is evident that the impact of these human activities, occurring over several decades and characterized by abusive industrial exploitation (including clearcutting, heat and smoke emissions from open-air furnaces and chimneys, industrial dust from foundries, acid rain, tailings ponds, and slag storage sites), justified the use of the term "lunar" to describe the barren landscape of Sudbury.
Visual observations highlighted the severe degradation of terrestrial and aquatic ecosystems, jeopardizing human biological existence and challenging the collective conscience. (Étongué-Mayer and Virchez, 1999). Rehabilitating the region's ecosystems thus became an imperative for legislators and the mining industry (Lautenbach et al., 1995).
3. INTERVENTIONS AND MANAGEMENT STRATEGIES
When the International Nickel Company (INCO) proposed the construction of an immense 381-meter chimney in 1969, the relationship between air pollution and ecosystem improvement raised limited controversy among scientists. While this measure would ensure wider dispersion of polluting emissions, it was recognized that the local retention of pollutants would decrease, potentially leading to a resurgence of plant activity and the return of terrestrial, avian, and aquatic fauna. However, the fundamental solution lay in reducing emissions at their source (Étongué-Mayer and Virchez, 1999).
The main sources of emissions were identified as the smelters operated by INCO and Falconbridge, which collectively emitted around 20% of the sulfur dioxide produced in Canada (Potvin and Negusanti, 1995). Initial measurements of air quality and efforts to control industrial sulfur dioxide emissions were conducted between 1969 and 1970, during which the Ontario government introduced modest measures to address air quality. These regulations partially mitigated environmental degradation by imposing stricter air quality standards on INCO and Falconbridge.
Nevertheless, these industries largely ignored concerns over sulfur dioxide emissions and acid rain. Observers noted that the indifferent attitude of company executives was a significant part of the problem. In response, the provincial government's incremental approach laid the groundwork for a comprehensive restoration program for degraded ecosystems. This initiative gained support from communities, industries, and other levels of government, forming a partnership led by researchers from Laurentian University.
The concept of long-range transboundary air pollution emerged in the 1970s when scientists linked ecological damage to acidifying pollutants transported long distances by prevailing winds (Environment and Climate Change Canada, 2024). After establishing a scientific database on soil properties, environmental constraints, and the economic consequences of rehabilitation in the Sudbury region, the scientific committee responsible for redevelopment began testing their chosen methodology (Lautenbach, 1995).
The City Council’s Advisory Panel on Regreening (VETAC) was established in 1973 with a mandate to restore self-sustaining, indigenous terrestrial and aquatic ecosystems in Greater Sudbury through the City’s Regreening Program. VETAC also provided opportunities for community involvement in environmental improvement at home, in neighborhoods, and on public lands (Monet, 2024).
To address poor soil conditions—characterized by high acidity, the absence of organic matter, and sensitivity to temperature variations—it was deemed necessary to reestablish plant cover (Winterhalder, 1996). Trials conducted at Coniston in 1974 involved soil treatment with limestone, fertilizer application, and plantings (Beckett, 1995). While various species were considered for reforestation, pine (Pinus) was identified as the most adaptable to the harsh conditions.
Improved site conditions led to modest success in plant reestablishment. Additionally, voluntary colonization by plant species from surrounding forests, including wildflowers and shrubs, contributed to the formation of specific ecosystems (Kellaway et al., 2022). Although high soil toxicity continued to hinder root system growth, progress was evident.
Following the evaluation of the Coniston trials, researchers developed a five-point strategy for rehabilitating barren land:
- Artificial phosphorus inputs and liming (10 tonnes/hectare) to reduce soil acidity.
- Fertilizer application (6-24-24 – N-P-K).
- Seeding of treated land with legumes (Canada bluegrass, Kentucky bluegrass, timothy, willowherb skullcap, and hybrid clover), using cutting techniques adapted to topography.
- Maintaining natural regrowth.
- Reforestation with conifers and deciduous trees (one to three years after liming).
Despite these efforts, recent analyses show that mine waste—particularly the dispersion of metal-laden dust in air and soil—continues to pose challenges in the region (Shorthouse and Bagatto, 1995).
The current state of the Sudbury region reflects not only the success of the extensive rehabilitation program initiated in 1978 but also the incorporation of environmental criteria into strategies for addressing regional challenges. Sudbury's image has transformed with the proliferation of green spaces, often thriving even on the steepest slopes. Various studies highlight the region's environmental improvements: Anand et al. (2005) explored diversity relationships among taxonomic groups in recovering and restored forests; Munford et al. (2024) examined the effects of large-scale restoration on understory plant communities in an industrial landscape; Snider (2024) analyzed total phosphorus concentrations in the Whitson River watershed; Kellaway et al. (2022) investigated soil liming; and Levasseur et al. (2023) documented improvements in tree growth and ecosystem carbon accumulation.
Key measures for environmental remediation are ad follows:
- Reduction of SO₂ Emissions. A crucial first step involved reducing sulfur dioxide emissions. This was achieved by constructing a 381-meter "Superstack," completed on August 21, 1970, which allowed for a 90% reduction in SO₂ emissions by dispersing pollutants over a wider area.
- Soil Liming. To counteract soil acidity, calcitic or dolomitic limestone (10 tons per hectare) was applied to increase the pH of the barren lands.
- Fertilizer Application. Fertilizers were introduced at a rate of 400 kg/ha using a formula of 6N-24P-24K to promote nutrient availability in the soil.
- Grassing of Barren Lands. Five grass species were sown to stabilize the soil and
encourage plant cover:
- Agrostis gigantea (20%)
- Festuca rubra (10%)
- Phleum pratense (20%)
- Poa compressa (15%)
- Poa pratensis (15%)
- Legume Seeding. Two types of legumes were included in the mix to enhance soil
fertility through nitrogen fixation:
- Lotus corniculatus (10%)
- Trifolium hybridum (10%)
- Tree and Shrub Planting. A variety of tree and shrub species were introduced to
establish a self-sustaining forest ecosystem:
- Pinus banksiana
- Pinus resinosa
- Pinus strobus
- Picea glauca
- Larix laricina
- Quercus borealis
- Robinia pseudoacacia
This summary of land reclamation treatments used on barren lands was adapted from Table 8.1 in Chapter 8 of Municipal Land Restoration by Lautenbach (1995).
4. CONCLUSION
From the onset of the mining industry in the early 1900s until the 1960s, the Sudbury area underwent a dramatic transformation from a vibrant, vegetation-rich landscape to a barren "moonscape" characterized by severe erosion and a lack of vegetation. From an economic perspective, the mining industry brought significant benefits, driving the prosperity of Sudbury and establishing it as the largest integrated mining complex in the world. The industry generated approximately $4 billion in annual exports and supported more than 300 mining supply firms, employing over 14,000 people.
However, this economic success came at a high environmental cost. It wasn't until the 1960s that genuine interest in environmental restoration emerged. The establishment of Laurentian University played a pivotal role, with its scientists collaborating closely with technical experts from INCO (later Vale) and Falconbridge (later Glencore). This partnership led to the construction of the 381-meter "Superstack" at an approximate cost of $25 million, owned by INCO, to disperse sulfur gases and other smelting by-products away from Sudbury. This innovation reduced sulfur emissions by 90%, paving the way for scientists to explore techniques to mitigate soil acidity and enable the reestablishment of vegetation.
Thus began the city’s Regreening Program. Since its inception in 1978, more than 3,500 hectares of land have been treated with lime and grassed, and over 10 million trees have been planted in efforts to rehabilitate Sudbury’s landscape and watersheds. By 2020, the Superstack was decommissioned, marking the success of the clean atmospheric emissions reduction project.
Equally critical to this transformation was the enactment of environmental legislation by the Provincial Government and the collaborative contributions of all three levels of government—Federal, Provincial, and Municipal. These efforts significantly supported the positive transformation of Sudbury's environment.
Finally, the contributions of committed citizens cannot be overstated. Their active participation and dedication were essential to the success of Sudbury’s regreening efforts. Without their involvement, the remarkable environmental recovery of the region would not have been possible.
REFERENCES
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4.
5.
6 .
7.
8.
9 .
10.
11.
12.
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21 .
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26 .
27 .
28 .
29.
30 .
31 .
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36 .
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38 .
39 .
40 .
41.
42 .
43 .
44 .
45 .