Bioindicators as Atmospheric Pollution Tracers: a Multi-Isotope Approach

Genevieve Vautour, GEOTOP-UQAM, Departement of Earth and atmospheric sciences, Montréal, Canada, Florence Gagnon, Université du Québec à Montréal, Département des Sciences de la Terre et de l'atmosphère, Montréal, QC, Canada, Andre Poirier, University of Quebec at Montreal UQAM, Montreal, QC, Canada and David Widory, GEOTOP-UQAM, Montreal, QC, Canada

Contact First Author: Genevieve Vautour; vautour.genevieve@courrier.uqam.ca

Abstract ID#: 35908

 

English Abstract:
Air quality has become in recent years a focus of attention worldwide because of its direct impact on human health. However, even if the monitoring of contaminant concentrations gives a first idea on air quality, it lacks the capacity to give indication about the source(s) and processes controlling the budget of the contaminants. Recent studies(1, 2) have suggested that an isotope approach can help alleviate this difficulty. Lately, bioindicators (including moss and lichens) have shown their added value as passive samplers for monitoring atmospheric contaminants due to their ombrotrophic nature and their lack of protective membrane that allow them to concentrate elements to levels exceeding their physiological needs.

Our study is set in the mining region of the Abitibi-Temiscamingue in eastern Ontario and seeks to differentiate the atmospheric metal contribution from two smelters (nickel and copper) in the area using the concentration and isotope ratios of lead (Pb), strontium (Sr) and osmium (Os). We collected lichen samples from a 500 km transect from the city of Sudbury, Ontario to Rouyn-Noranda, Québec. The Sudbury region is home to Vale’s and Glencore’s nickel smelters. Osmium is a trace metal commonly found as a –significant- impurity in nickel and platinum ores. In the city of Rouyn-Noranda, 300 km from Sudbury, Glencore operates a copper smelter.

We previously conducted a similar study in two different environments: Hawaii, USA and Rigaud, Québec. The first is a recent basaltic island sourced from a mantle plume while the second is an old granitic intrusion (564 Ma(3)) within the sedimentary basin of the St. Lawrence Lowlands. The strontium and lead isotope ratios of the bioindicators differentiate between two natural sources (local basaltic rocks and the oceanic input) in Hawaii, and between natural and anthropogenic sources in Rigaud. The osmium isotope analyses will be conducted by the time we meet in Montreal.

References:

1) Lahd Geagea et al. (2007) Environmental Science and Technology

2) Rodushkin et al. (2007) Science of the Total Environment

3) Malka et al. (2000) The Journal of Geology

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