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Using diatom assemblages and sulphur in sediments to uncover the effects of historical mining on Lake Arnoux (Quebec, Canada): A retrospective of economic benefits versus environmental debt.

Hamilton, Paul B.; Lavoie, Isabelle; Alpay, Sam; Ponader, Karin (2015). Using diatom assemblages and sulphur in sediments to uncover the effects of historical mining on Lake Arnoux (Quebec, Canada): A retrospective of economic benefits versus environmental debt. Frontiers in Ecology and Evolution , vol. 3 . p. 99. DOI: 10.3389/fevo.2015.00099.

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Résumé

Monitoring changes in environmental conditions is increasingly important as the Canadian economic infrastructure ramps up exploration and mining development in the more inaccessible northern regions of Canada. Governments are concurrently assessing effects from past mining activities and absorbing the economic cost to society with on-going remediation and monitoring initiatives. The abandoned Aldermac mine in northwestern Quebec, mined from 1932 to 1943, is an excellent case study for assessing the state of environmental and economic effects of past mining operations. A paleolimnological approach, using diatoms as environmental proxies, was used to evaluate the spatial and temporal impacts on aquatic receiving environments. Based on the inferences drawn from diatom assemblages in Lake Arnoux, prior to mining activity, lake water pH was similar to that of surrounding lakes (circumneutral to weakly acidic). After mining operations terminated, changes in pH and alkalinity in Lake Arnoux coincided with distinct increases in sediment sulfur content. Across a 30- to 40-year span (circa 1940–1970s) a significant decline in phytoplankton flora coincided with lake acidification and increased clarity of the water column. This resulted in an increase in the benthic diatom population (>90%), replacing the planktonic diatoms. Observed shifts in environmental proxies are concurrent with one, and possibly two, reported tailings pond breaches at the abandoned mine site. Adverse effects of the abandoned Aldermac mine on nearby ecosystems, combined with pressure from local citizens and environmental groups, forced responsible accountability for site restoration led by the Quebec government. Based on the historical period of economic growth, the financial benefits of the Aldermac mine were significant and justify the current pay-it-backward costs for environmental remediation. However, it has now been documented that the pay-it-backward model is not sustainable in the modern economy. New pay-it-forward approaches, addressing our gray water footprint, are required to merge economic and environmental sustainability for future prosperity.

Type de document: Article
Mots-clés libres: diatoms; pH,acid mine; drainage; biomonitoring; paleolimnology; sulphur; Aldermac mine; Lake Arnoux–Dasserat system
Centre: Centre Eau Terre Environnement
Date de dépôt: 27 avr. 2018 19:39
Dernière modification: 27 avr. 2018 19:39
URI: http://espace.inrs.ca/id/eprint/4314

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