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TitreLake sediment grab sampling versus coring for environmental risk assessment of metal mining
AuteurAlpay, S; McNeil, R J; Grenier, A; Gould, W D
SourceL'Association géologique du Canada-L'Association minéralogique du Canada, Réunion annuelle conjointe, Recueil des résumés vol. 37, 2014 p. 8
LiensOnline - En ligne
Année2014
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130452
RéunionGeological Association of Canada - Mineralogical Association of Canada Joint Annual Meeting; Fredericton; CA; mai 21-23, 2014
Documentpublication en série
Lang.anglais
Mediapapier
Référence reliéeCette publication est reliée Alpay, S; Alpay, R J; Grenier, A; Gould, W D; (2014). Lake sediment grab sampling versus coring for environmental risk assessment of metal mining, Commission géologique du Canada, Présentation scientifique no. 26
Formatspdf
ProvinceQuébec
SNRC32D/03; 32D/06
Lat/Long OENS-79.5333 -79.2000 48.3500 48.0000
Sujetsetudes de l'environnement; effets sur l'environnement; méthodes d'exploitation minière; exploitation minière; contamination des métaux lourds; cuivre; zinc; or; argent; géologie économique; géologie de l'environnement
ProgrammeOutils d'adaptation et d'impacts sur l'environnement pour les mines de métaux, Géosciences de l'environnement
Résumé(disponible en anglais seulement)
Current practices for baseline studies of sites to be developed for mining include surface grab sampling of sediments in aquatic receiving environments. In contrast, vertical sediment coring is a universal tool in paleolimnological research. This study evaluates the effectiveness of sediment grab sampling versus sediment coring for environmental risk assessment of metal mining. The former Aldermac mine (Cu, Zn, Au and Ag), 15 km west of Rouyn - Noranda in Abitibi, Quebec, operated from 1932 - 1943 and discharged acid mine drainage into the watershed downstream. The study area is representative of both a common mineral deposit type and historical mining practices. Surveys of bulk sediment grab samples (2011 - 13) were done using a Ponar® sampler that penetrated to a depth of approximately 5 - 10 cm at 34 sampling sites. Co - located sediment cores, 30 - 45 cm long, were collected using a modified 10 - cm diameter gravity corer at 33 sites and were subsampled at 0.5 to 5 - cm depth intervals. Geochemical results from quick regional grab sampling provided estimates of baseline metal concentrations in surface sediments, contaminant sources, and the spatial extent of metal contamination. Sediment samples retrieved by longer cores produced estimates of both spatial and temporal factors: naturally - occurring metal concentrations (pre - industrial background), current metal concentrations, contaminant sources, and the duration and spatial extent of contamination. Although regional grab samples provide more sample material and are faster and simpler to collect than gravity coring, the results are imprecise because they are bulk data integrated over roughly 5 - 10 cm of depth; they also lack a time dimension. Coring, core extrusion, and subsampling at distinct depth intervals provide chemical stratigraphy of metal deposition. Coring also affords potential for more targeted data to fingerprint contaminant sources, assess diagenetic metal mobility, and determine stability of metal - bearing phases at discrete sediment horizons. These research-grade investigations can be optimized for practical use in environmental risk assessment. Bulk grab sampling offers a first approximation of regional metal distributions in shallow sediments. However, when more detailed investigation is warranted under environmental risk assessment regulations, sediment coring can not only provide estimates of the true ranges of naturally - occurring metal concentrations (natural background), but also measurements and timelines of metal increases from industrial activities.
Résumé(Résumé en langage clair et simple, non publié)
Différentes méthodes d'échantillonnage de sédiments aquatiques en aval d'un site contaminé connu (l'ancienne mine Aldermac, en Abitibi, Québec) sont présentées pour démontrer les options pour l'évaluation du risque environnemental des mines de métaux. L'échantillonnage de sédiments en vrac peu profondes est rapide et les résultats estiment les conditions de base (avant nouveau développement), les sources de contamination, et l'étendue spatiale de la contamination, bien que la méthode génère des données imprécises sans la dimension temporelle. Quand l'étude plus avancée est nécessaire, les carottes de sédiments fournissent les résultats pour determiner la contamination de métaux accumulée au fil du temps, une plus grande précision, et des données plus ciblées (par exemple, pour identifier les sources de contamination et la mobilité des métaux).
GEOSCAN ID293597