Sequential sample reservoirs for Itrax-XRF analysis of discrete samples

Gregory, Braden R.B.; Reinhardt, Eduard G.; Macumber, Andrew; Nasser, Nawaf A.; Patterson, R. Timothy; Kovacs, Shawn E.; Galloway, Jennifer M.

doi:10.1007/s10933-017-9944-4

Cited by 21 publications

(27 citation statements)

References 12 publications

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“…The elemental geochemistry of the sediment samples was measured by an Olympus X-50 portable X-ray fluorescence (pXRF) spectrometer, following methods outlined by Rouillon and Taylor (2016), Loder et al (2016), and Dunnington et al (2016). XRF spectrometry is a method that is increasingly used to provide high-resolution elemental geochemistry in lake sediments (Koinig et al 2003;Guyard et al 2007;Brunschön et al 2010;Kylander et al 2011;Rydberg 2014;Dunnington et al 2016;Gregory et al 2017). Rouillon and Taylor (2016) demonstrated that pXRF was able to produce as good or better recoveries than ICP-AES for 9 of 11 elements assessed in the study (Ti, Cr, Mn, Fe, Cu, Zn, Sr, Cd, and Pb).…”

Section: Age-depth Modelmentioning

confidence: 99%

A paleolimnological archive of metal sequestration and release in the Cumberland Basin Marshes, Atlantic Canada

Dunnington

White

Spooner

et al. 2017

FACETS

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We used a paleolimnological approach at Long Lake, Nova Scotia, to construct a 10 500-year record of metal deposition in lakebed sediments and elucidate the influence of both natural and anthropogenic environmental changes. Aquatic sediment concentrations of mercury (Hg), arsenic (As), and chromium (Cr) in Long Lake fluctuated substantially and, during some periods, exceeded guidelines for the protection of aquatic life. Increases in lead (Pb), Hg, Cr, trace metals, and nitrogen stable isotopes (δ 15 N) were broadly coincident with a period of widespread drying from ca. 8000 to 4000 cal BP and were likely a consequence of regional fires. From ca. 4000 cal BP until 1700 AD, metal levels in general were low due to decreased erosion, increased precipitation, and reduced fire activity. Water level lowering and forced sediment aggradation (tiding) in the 1800s led to increases in minerogenic Pb and Cr, though fossil fuel combustion also likely contributed to total Pb concentrations. Stratigraphic proxies indicated increased inorganic sedimentation rates, and reduced autochthonous productivity were coincident with lower Hg and As concentrations in the Long Lake sediment. Our data indicate that natural phenomena (fire) can result in sediment contaminant exceedances, that most metals have multiple sources, and that both human-induced disturbance and emissions have contributed to Pb contamination in the last 200 years. In addition, wetter and generally cooler climate appeared to favour lower concentrations of contaminants in lake sediments. Although wetland sediments in the Cumberland Basin Marshes are not heavily polluted with metals, the development of constructed wetlands and the disruption of aquatic sediments have the potential to concentrate, mobilize, and increase the bioavailability of metals.

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Section: Age-depth Modelmentioning

confidence: 99%

A paleolimnological archive of metal sequestration and release in the Cumberland Basin Marshes, Atlantic Canada

Dunnington

White

Spooner

et al. 2017

FACETS

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“…Preparation of subsamples for XRF-CS followed Gregory et al (2017). Sediment was stirred using a spatula to homogenize material, then approximately 20 mL of wet sediment (more for watery samples) was subsampled into 50 mL falcon tubes, centrifuged at 4000 rpm for 4 minutes and the supernatant decanted; if time allows, samples can be dried at room temperature to the required consistency to ensure no material is lost during decanting of samples.…”

Section: Laboratory Methodsmentioning

confidence: 99%

“…Sediment was stirred using a spatula to homogenize material, then approximately 20 mL of wet sediment (more for watery samples) was subsampled into 50 mL falcon tubes, centrifuged at 4000 rpm for 4 minutes and the supernatant decanted; if time allows, samples can be dried at room temperature to the required consistency to ensure no material is lost during decanting of samples. Each sample was covered to minimize the possibility of contamination, and then left at room temperature to dry until sediment samples reached a paste-like consistency that enables easy loading and reduces the risk of cross contamination (Gregory et al 2017). The dried samples were transported to the McMaster University Core Scanning Facility, homogenized by stirring with a spatula, loaded into an acrylic SSR (1 x 1 x 1.5 cm = 1.5 cc), and analyzed using a Cox Analytics Itrax core scanning X-ray fluorescence (Itrax-XRF-CS) device.…”

Section: Laboratory Methodsmentioning

confidence: 99%

“…XRF-CS sediment data were isolated from the extraneous measurements of the SSR acrylic reservoir dividers and floral foam before calibration attempts. Gregory et al (2017) were able to easily discriminate acrylic dividers from sediment on the basis of the abrupt shifts in the ratio of coherent to incoherent X-ray scatter (CIR), known width of the acrylic compartment walls, total counts per second (kcps), and abundance of the elements (Fe and Ca) in sediment. Subsequent to removal of the non-sediment XRF-CS data points, at least 15 and up to 67 discrete sample measurements remained for each sample depending on whether or not floral foam had been required to fill excess space in sample reservoirs.…”

Section: Methodsmentioning

confidence: 99%

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Understanding the impact of millennial to sub-decadal climate and limnological change on the stability of As in lacustrine sediments

Gregory¹

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Metal(loid)s are expected to respond to 21st century warming as their stability in lacustrine systems is indirectly influenced by regional temperature and precipitation. In the Northwest Territories (NT), arsenic (As) is a metal(loid) of environmental concern due to elevated concentrations in bedrock and widespread mining-related contamination. To characterize the response of As to long-and short-term climate variability, we developed techniques that enable high temporal resolution analyses of sediment freeze cores, and applied them to a sediment cores (CON01, CON02) recovered from Control Lake, NT. New equipment was designed to enable Itrax X-ray fluorescence (Itrax-XRF) analysis of discrete sediment samples (Chapter 2). This equipment was used to test calibration methods that convert semi-quantitative Itrax-XRF results to near-total geochemical concentrations (Chapter 3). We found that the multi-variate log-ratio calibration provided the best approximation of actual geochemical concentrations. Subsequently, equipment was designed to permit scanning of freeze-cores using Itrax-XRF (Chapter 4). To characterize millennial-scale shifts in sedimentary As concentration in response to climate change, Arcellinida and ICP-MS analysis were conducted on core CON01 that recorded 4000 yr of sedimentation (Chapter 5). Arsenic concentrations the in core were related to shifts in the proportion of organic matter and shifts in minerogenic content (Rb, K). Comparison to regional records suggests changes in temperature impacted autochtonous productivity, which is hypothesized to have influenced sedimentary As concentrations. To characterize the response of As to quasi-periodic climate oscillations, CON02 was analyzed using Itrax-XRF. Itrax-XRF data were calibrated to paired ICP-MS data, and geochemical proxies for particle size (log(Zr/Ti)), in-lake productivity (log(Ca/Ti)), and As preservation (log(As/Ti)) were examined for cyclities using spectral and wavelet analyses. Periods of 8-15, 30-60, 90-130, and 180-300 yr were observed in all proxies. These periods are temporally related to the North Atlantic Oscillation/El niño/Schwabe sunspot cycles, the Pacific Decadal Oscillation, the Gleissberg cycle, and the Suess cycle, respectively. Cross-wavelet analysis of the paleo-proxies vs. published total solar irradiance reconstructions demonstrate significant relationships, suggesting a solar influence on climate and lake sediment geochemistry in the NT. These results suggest that As sequestration is impacted by short-period climate perturbations. Gregory et al 2019 iii Acknowledgments First and foremost, thank you to my co-supervisors Dr. Jennifer Galloway and Dr. Timothy Patterson, whose passion for science and support helped make this dissertation a reality. Thank you for pushing me to publish and present. Thank you to Dr. Eduard Reinhardt. You took me on as an undergraduate student and put me on the path to academia. Without your guidance I would not be into science, coffee or baking as I much as I am today. Thank you to my colle...

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“…End member mixing analysis (EMMA) of grain size results can further be used to model the depositional signature (i.e., end members) of specific catchment and lake hydrological processes (Weltje & Prins, 2003, 2007Dietze et al, 2012;Macumber et al, 2018). The development of XRF-CS core scanning technology has revolutionized geological research as it can be used to analyze sediment geochemistry much faster and with lower cost than traditional geochemical techniques (Gregory et al, 2017;Bloemsma et al, 2018). Spatial variability of elements such as Ti can identify areas of frequent resuspension that are characterized by coarser grains enriched with Ti versus areas of deposition associated with finer grains enriched with Al (Taboada et al, 2006;Boës et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

A novel protocol for identifying storm derived waves on substrate reworking in lakes: implications for selection of optimal sites for paleolimnological research

Mazzella¹

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Harvey Lake, located within the Atlantic region of Canada, endures many storms, including Hurricane Arthur in 2014, and likely archives lake sediment records including past storm signals. Lakes are often characterized by a single central site, rather than a suite of sites, due to cost and time constraints. This research sought to develop a novel geomatics protocol to optimize coring site selection using a multi-site (n = 96) characterization. Areas prone to resuspension were modeled using lake morphology and historical wind speed records (1953-2015). Modeled resuspension areas agreed with the spatial distribution of sedimentary proxies (i.e., grain size and Itrax-XRF). End member mixing analysis identified a very coarse grain end member that likely reflects the deposition of resuspended sediments. In addition to the central basin, our approach highlighted Herbert's Cove as a suitable coring target as it was in closer proximity to a source of allochthonous sedimentation (i.e., catchment hydrological signal).

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Sequential sample reservoirs for Itrax-XRF analysis of discrete samples

Cited by 21 publications

References 12 publications

A paleolimnological archive of metal sequestration and release in the Cumberland Basin Marshes, Atlantic Canada

A paleolimnological archive of metal sequestration and release in the Cumberland Basin Marshes, Atlantic Canada

Understanding the impact of millennial to sub-decadal climate and limnological change on the stability of As in lacustrine sediments

A novel protocol for identifying storm derived waves on substrate reworking in lakes: implications for selection of optimal sites for paleolimnological research

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