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Method for Extraction and Multielement Analysis of Hypogymnia Physodes Samples from the Athabasca Oil Sands Region
Citation:
Edgerton, E., M. Fort, K. Baumann, J. Graney, M. Landis, S. Berryman, AND S. Krupa. Method for Extraction and Multielement Analysis of Hypogymnia Physodes Samples from the Athabasca Oil Sands Region. Chapter 14, Alberta Oil Sands: Energy, Industry, and the Environment. Elsevier Ltd, Oxford, Uk, 11:315-341, (2012).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL′s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA′s mission to protect human health and the environment. HEASD′s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA′s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
A microwave-assisted digestion technique followed by ICPMS (inductively coupled plasma-mass spectrometry) analysis was used to measure concentrations of 43 elements in Hypogymnia physodes samples collected in the Athabasca Oil Sands Region (AOSR) of northern Alberta, Canada. Analysis of multiple standard reference materials, replicate samples, and digestion blanks indicates that 34 elements were routinely quantifiable in small samples of lichens (25–30 mg) from the AOSR. Analysis of As and Se was performed by dynamic reaction cell ICPMS techniques to minimize polyatomic interferences and improve detection limits. Data from 121 sampling locations show that concentrations of many elements are higher (factors of 1.5–3) near the oil sands operations (i.e., within 50 km) than further away (i.e., beyond 50 km). Statistical analysis shows that many of the 34 elements (particularly the rare earth elements) are highly correlated, but others only have weak correlations with a few other elements. Linear regression of element concentrations versus Al indicates a range of behavior across elements that likely reflect multiple accumulation processes. Comparison with previous studies of H. physodes shows that elemental concentrations within the AOSR are generally comparable but often toward the lower end of those reported for remote and background areas of the northern hemisphere. Sb and Pb concentrations, in particular, are among the lowest reported for H. physodes.