Atlas of Contaminated Sites

Notable case, Greater Sudbury, Ontario, Canada

Sudbury

A nickel and copper district where a century of roasting and smelting sulphide ores destroyed the vegetation over tens of thousands of hectares and blackened the rock. Since 1978 the city has run a regreening programme using lime, grasses and trees.

Phytoremediation

Status
Remediation under way
Area
33,350 ha on land1
Activity
since 1888
Media
soil, air, surface water
Kind of site
smelter, mining
  1. Area. By 2010, 3,350 hectares had been rehabilitated and about 30,000 remained to be treated (Wikipedia). The coordinates mark Copper Cliff, where the smelter stands.

Contaminants

Metals

Other inorganics

Status

Remediation under way

The regreening programme has run for 45 years: by 2023 more than 3,500 hectares limed and grassed and over 10 million trees planted (City of Greater Sudbury). The smelters are still operating.

Story

Inco's (now Vale's) Copper Cliff smelter dates from 1888; the other major operator was Falconbridge (now Glencore). Open-air roasting of ore in the first half of the 20th century, and logging to fuel it, caused a near-total loss of the native vegetation. Sulphur released by smelting, turned into sulphuric acid, came down as acid rain: the rock outcrops turned black, with the acid reaching up to 76 mm into the granite.

In 1972 Inco built the Superstack, which spread the emissions over a much wider area and lowered the acidity of local rain. In the late 1970s the city began regreening: lime spread by hand and by aircraft to neutralise the soil's acidity and toxicity, then fertiliser, grass seeding and finally the planting of tree seedlings. In 1992 Sudbury was one of twelve cities honoured by the United Nations at the Earth Summit.

Timeline

  1. 1888Copper Cliff smelter.
  2. 1972The Superstack is built.
  3. 1978Regreening programme begins.
  4. 1992United Nations award at the Earth Summit.
  5. 20109.2 million trees planted and 3,350 hectares rehabilitated.
  6. 2023More than 10 million trees and 3,500 hectares limed and grassed.

Remediation

  1. 1972emission dispersionSuperstack: sulphur emissions dispersed over a wider area.

Plants and fungi at this site

PhytoremediationField scale, 1978–

Municipal regreening programme: limestone is applied to barren land to neutralise soil acidity and toxicity, followed by fertiliser and grass seed; once the sward is established, tree seedlings are planted and forest-floor mats transplanted. In effect it is amendment-assisted phytostabilisation at landscape scale. The pages consulted do not list the species.

Outcome By 2023: more than 3,500 hectares limed and grassed and over 10 million trees planted. In 2010 about 30,000 hectares still remained to be treated.

PhytoremediationField scale, 1978–

Betula spp., Populus spp., Salix spp.

Since 1978 the Regional Municipality of Sudbury has spread ground limestone by hand on the bare soil, with or without fertiliser and a grass-legume seeding, and planted native conifers in groups as a seed source.

Outcome Liming makes the soil just non-toxic enough to start immediate spontaneous colonisation by birch, aspen and willows: by 1996 more than 3,000 hectares had been treated in this way. The metals stay in the soil: this is regreening by stabilisation, not removal.

From the literature

Species that acted on one of this site's contaminants in at least one study. The list is automatic and takes no account of this site's soil, concentrations or climate.

Plants

Fungi

The rest are on the contaminant pages.

Sources

  1. Regreening Program, City of Greater Sudbury, 2023
  2. Greater Sudbury, Wikipedia, 2026

Draft compiled from public sources, not yet reviewed.