MSc students

Julie Arteau

Status: MSc candidate

Codirector: Etienne Boucher (UQAM)

Title: Historical reconstitution of atmospheric metallic depositions in Montreal from the coupled study of metal concentrations and multi-isotopic systematic (O, C, Pb) in tree rings

Several studies have shown the potential of dendrogeochemistry approach to reconstruct the history of environmental anthropogenic disturbances over long periods by studying the concentrations and/or isotopic ratios of elements contained in tree growth rings. However, the use of tree rings as an “active” indicator of air pollution is a controversial method because of the influence of physiological parameters (e.g. lateral movement) and climatic factors (e.g. precipitation, temperature) that modulates the assimilation and distribution of elements in tree. Some tree species and elements proved to be more suitable to extract meaningful information from the chemistry of tree-rings. To overcome these physiological limitations, the combination of several indicators (e.g. multi-isotopic) is actually prioritized in this field of study in order to provide a realistic portrait of the retrospective predictions of anthropogenic pollution. Here we proposed to combine the analyses of metals concentrations (Al, Cu, Pb, Zn, Cd, Cr) and systematics isotopics of Pb, O, C in silver maple tree rings.

Marjorie Bagur

Status: MSc candidate

Title: Lead (Pb) and Osmium (Os) isotope characteristics of PM10 aerosols from the atmosphere of Montreal

In 1969, the city of Montréal established a network of sampling stations to monitor the air quality on the island. These stations collect aerosols (TSP in our study; total suspended particles) at various locations representative of specific environments: downtown, harbor, road traffic… In collaboration with the Ville de Montréal, we monitored the variations of TSP concentrations between 1973 and 2013. Results show several decreases in the TSP levels that usually follow the implementation of mitigation measures by the government. The analysis of the Pb atmospheric concentrations identified three stages: 1) During 1973, with atmospheric Pb increasing at a rate of 1 µg/m3/year, 2) between 1978 and 1988, when Pb concentrations decreased at a rate of 0.05 µg/m3/year and 3) since 1993 with a somewhat slower decrease in atmospheric Pb. The addition of Pb isotopes allowed us to identify three distinct periods and the main source of contamination for each of them: While the combustion of leaded gasoline explains the first period (1973 to 1983), emissions from US industries mainly contribute to the Pb atmospheric budget between 1988 and 2002. From then atmospheric Pb is characterized by a mixture of sources that seems to reflect a higher contribution of terrigenous Pb. On the other hand, osmium (Os) atmospheric concentrations are roughly constant over the same period. However, its stable isotope ratios reveal that its atmospheric budget can be explained by a ternary relationship whose three end members are represented by road traffic (catalytic converters), terrigenous sources and the local background.

Karelle Trottier

Status: MSc candidate

Codirector: Daniel Germain (UQAM)

Title: Impact of an abandoned mining pit on the local environment in Romania

Fanny Pithon

Status: MSc candidate

Codirector: Marie Larocque (UQAM)

Title: Assessing water quality in the Laurentides region (Québec)

Zeinebou Laraibi

Status: Professional MSc candidate

Title: Lead (Pb) environmental contamination: the examples of aerosols (Tarragona, Spain), bioindicators (Paris, France) and soils (Colombia).

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