Mercury flux from naturally enriched bare soils during simulated seasonal cycling

dc.contributor.advisorVan Heyst, Bill
dc.contributor.authorWalters, Nicholas of Engineeringen_US of Guelphen_US of Applied Scienceen_US
dc.description.abstractMercury (Hg) is a potent human toxin and a persistent global pollutant with unique properties and environmental behaviours which make it difficult to model and understand. While anthropogenic mercury sources are well understood along with the impacts on ecosystems and human populations, the processes and transformations which govern environmental cycling lack the same level of understanding. Concentrations in Arctic environments are a specific concern, along with cycling behaviours in regions spanning from temperate to Arctic climates. The objective of this experiment was the investigation and characterization of the mechanisms which promote elemental mercury (Hg^0) flux from soils in these environments during simulated seasonal cycling. A laboratory scale experiment was conducted which used a Dynamic Flux Chamber (DFC) to monitor Hg^0 flux from a naturally Hg enriched soil during temperature cycling relevant to cold environments. The results, which were split into freeze-thaw (FT) and sub-zero (SZ) cycles, showed that Hg^0 flux from frozen soils remains active during temperature cycling. During FT cycles, Hg^0 flux is controlled by soil temperature and energy entering the system, with a linear increase in flux for increases in energy. This response is produced from the entire soil column. During SZ cycles, Hg^0 flux is produced only in the thin soil surface layer and is controlled by the air temperature at the soil-air interface. A decrease in the DFC air temperature was observed to produce an increase in flux, with an inverse relationship controlled by a separate mechanism than the FT cycle response. Recommendations for modifications to the experimental set-up and methodology have been made to improve the accuracy of the results and confirm the behaviours characterized during this study.en_US
dc.description.sponsorshipNatural Sciences and Engineering Research Council of Canada
dc.publisherUniversity of Guelphen_US
dc.rights.licenseAll items in the Atrium are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectphase changeen_US
dc.subjecttemperature cyclingen_US
dc.subjectelemental mercury fluxen_US
dc.subjectdynamic flux chamberen_US
dc.subjectsoil moistureen_US
dc.titleMercury flux from naturally enriched bare soils during simulated seasonal cyclingen_US


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