Solid-phase speciation and post-depositional mobility of arsenic in lake sediments impacted by ore roasting at legacy gold mines in the Yellowknife area, Northwest Territories, Canada

2018 ◽  
Vol 91 ◽  
pp. 208-220 ◽  
Author(s):  
Christopher E. Schuh ◽  
Heather E. Jamieson ◽  
Michael J. Palmer ◽  
Alan J. Martin
Keyword(s):  
Lake Sediments ◽  
Northwest Territories ◽  
Solid Phase ◽  
Gold Mines ◽  
Ore Roasting

Eunotia spp. (Bacillariophyceae) from Middle Eocene lake sediments and comments on the origin of the diatom raphe

2007 ◽  
Vol 85 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Peter A. Siver ◽  
Alexander P. Wolfe
Keyword(s):  
Lake Sediments ◽  
Northwest Territories ◽  
Middle Eocene ◽  
Valve Morphology ◽  
Progressive Degeneration ◽  
Extant Species ◽  
Freshwater Diatoms ◽  
Molecular Phylogenetic

Freshwater diatoms belonging to the genus Eunotia Ehrenberg 1837 are well preserved in Middle Eocene lake sediments from the Northwest Territories, Canada. Although two distinct valve morphologies are recognized, both have features that are entirely compatible with modern congeneric taxa, including dorsiventral valve morphology, striae spanning the valve face and extending onto the mantle, raphe structures on the mantle that extend distally onto the valve face, two helictoglossae per valve, and one apical rimoportula per valve. These findings establish that the genus Eunotia, and likely freshwater raphid diatoms as a whole, are more ancient than previously believed, dating back to at least 40 Ma. One of the observed morphotypes has a raphe spanning more than 80% of the valve length as well as a narrow hyaline area extending between proximal raphe endings and interrupting mantle striae. These features imply that the raphe system among certain ancient representatives of Eunotia was more developed relative to modern counterparts. The notion of progressive degeneration of the raphe within Eunotia is supported by several extant species. Collectively, these observations confirm molecular phylogenetic arguments that position Eunotia as a basal raphid diatom.

scholarly journals Geochemical data for lake sediments and surface waters, Abitau Lake area, Northwest Territories (NTS 75-B)

2016 ◽  
Author(s):  
M W McCurdy ◽  
S J Pehrsson ◽  
H Falck ◽  
S J A Day ◽  
J E Campbell
Keyword(s):  
Lake Sediments ◽  
Northwest Territories ◽  
Surface Waters ◽  
Geochemical Data ◽  
Lake Area

scholarly journals Textural, Mineralogical and Geochemical Assessment of the Pikrolimni Lake Sediments (Kilkis District, Northern Greece) and Suitability for use in Pelotherapy

2019 ◽  
Vol 55 (1) ◽  
pp. 170
Author(s):  
Emilia Sofianska ◽  
Constadinos Athanassoulis ◽  
Dimitrios Tarenidis ◽  
Nikolaos Xirokostas ◽  
Maria Gkagka
Keyword(s):  
Lake Sediments ◽  
Inductively Coupled Plasma ◽  
Toxic Elements ◽  
Solid Phase ◽  
Sandy Loam ◽  
Chemical Properties ◽  
Raw Material ◽  
Northern Greece ◽  
Mean Values ◽  
X Ray

Pelotherapy is the application of thermal muds (peloids) for recovering muscle, bone and skin pathologies. Specific criteria were established for the evaluation of the therapeutic suitability of peloids. Critical factors ruling the quality of the solid phase of peloids include granulometry, mineralogy, and physical-chemical properties. The aim of the present study was to investigate the textural, mineralogical and geochemical characteristics of the Pikrolimni Lake sediments (PLS), Kilkis district (N. Greece) in order to assess their suitability for application as raw material into mud therapy technologies. Representative PLS samples were collected and analyzed by means of different techniques at the analytical laboratories of the Hellenic Survey of Geology and Mineral Exploration (HSGME). Results showed that, texturally, the PLS were classified as sandy loam sediments. X-ray diffraction (XRD) study revealed that the PLS consist mainly of quartz, clay minerals (kaolinite, montmorillonite, illite), and muscovite, with minor feldspar and calcite. X-ray fluorescence (XFR) analysis showed that PLS samples have higher SiO2 and lower Al2O3 contents compared to the average shale composition. Among the analyzed, by means of inductively coupled plasma mass spectrometry (ICP-MS) technique, potentially toxic elements only As and Pb contents were found significantly higher than those of the average shale. Based on the calculated mean values of enrichment factor (EF) and geo-accumulation index (Igeo) PLS displayed minor enrichment and moderate contamination by Pb and As, respectively. In conclusion, an improvement of the grain size composition of PLS by means of a sieving process is needed. Besides, the study of the concentration and behavior of toxic elements in peloids formed by the mixing of the processed PLS with salty thermo-mineral water is proposed.

Quantifying arsenic post-depositional mobility in lake sediments impacted by gold ore roasting in sub-arctic Canada using inverse diagenetic modelling

2021 ◽  
pp. 117723
Author(s):  
Émilie Leclerc ◽  
Jason J. Venkiteswaran ◽  
Izabela Jasiak ◽  
James V. Telford ◽  
Mackenzie D.J. Schultz ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Arctic Canada ◽  
Gold Ore ◽  
Ore Roasting

scholarly journals Influence of late-Holocene climate change on the solid-phase speciation and long-term stability of arsenic in sub-Arctic lake sediments

2020 ◽  
Vol 709 ◽  
pp. 136115 ◽  
Author(s):  
Clare B. Miller ◽  
Michael B. Parsons ◽  
Heather E. Jamieson ◽  
Omid H. Ardakani ◽  
Braden R.B. Gregory ◽  
...  
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
Late Holocene ◽  
Solid Phase ◽  
Holocene Climate ◽  
Arctic Lake ◽  
Term Stability ◽  
Long Term Stability ◽  
Holocene Climate Change

scholarly journals Grain-Scale Analysis of Solid-Phase Organic Matter and Arsenic Mobility in Mining-Impacted 1 Sediment from Sub‐Arctic Lakes, Northwest Territories, Canada

2021 ◽  
Author(s):  
Clare B Miller ◽  
Michael B Parsons ◽  
Heather E Jamieson ◽  
Omid H Ardakani ◽  
R Timothy Patterson ◽  
...  
Keyword(s):  
Organic Matter ◽  
Northwest Territories ◽  
Solid Phase ◽  
Arctic Lakes ◽  
Edge Structure ◽  
Near Surface ◽  
X Ray ◽  
Fine Grained ◽  
Arsenic Mobility ◽  
Co Precipitation

Abstract Arsenic (As) is commonly sequestered at the sediment-water interface (SWI) in mining-impacted lakes through adsorption and/or co-precipitation with authigenic iron (Fe)-(oxy)hydroxides or sulphides. The results of this study demonstrate that the accumulation of solid-phase organic matter (OM) in near-surface sediments also influences the mobility and fate of As in sub-Arctic lakes. Sediment gravity cores, sediment grab samples, and porewaters were collected from three lakes downstream of the former Tundra gold mine, Northwest Territories. Analysis of sediment using combined micro-X-ray fluorescence/diffraction, K-edge X-ray Absorption Near-Edge Structure (XANES), and organic petrography shows that As is associated with both aquatic (benthic and planktonic alginate) and terrestrially-derived OM (cutinite; funginite). Most As is hosted by fine-grained Fe-(oxy)hydroxides or sulphide minerals ( e.g., goethite, orpiment, lepidocrocite, mackinawite); however, grain-scale synchrotron-based analysis shows that As is also associated with amorphous OM. Mixed As oxidation states in porewater (median = 62 % As (V), 18 % As (III); n = 20) and sediment (median = 80 % As (-I) and (III), 19 % As (V); n = 9) indicate the presence of variable redox conditions in the near-surface sediment and suggest that post-depositional remobilization of As has occurred . Detailed characterization of As-bearing OM at and below the SWI suggests that OM plays an important role in stabilizing redox-sensitive authigenic minerals and associated As. Based on these findings, it is expected that increased concentrations of labile OM will drive post-depositional surface-enrichment of As in mining-impacted lakes and may increase or decrease As flux from sediments to overlying surface waters.

scholarly journals Vertical distribution of Fe and Fe(III)-reducing bacteria in the sediments of Lake Donghu, China

2015 ◽  
Vol 61 (8) ◽  
pp. 575-583 ◽  
Author(s):  
Cuicui Tian ◽  
Chunbo Wang ◽  
Yingying Tian ◽  
Xingqiang Wu ◽  
Bangding Xiao
Keyword(s):  
Vertical Distribution ◽  
Lake Sediments ◽  
Solid Phase ◽  
Inorganic Phosphorus ◽  
Nitrogen And Phosphorus ◽  
Inorganic Substances ◽  
Reducing Bacteria ◽  
The Vertical Distribution ◽  
Insight Into ◽  
Phosphorus Levels

In lake sediments, iron (Fe) is the most versatile element, and the redox cycling of Fe has a wide influence on the biogeochemical cycling of organic and inorganic substances. The aim of the present study was to analyze the vertical distribution of Fe and Fe(III)-reducing bacteria (FeRB) in the surface sediment (30 cm) of Lake Donghu, China. At the 3 sites we surveyed, FeRB and Fe(II)-oxidizing bacteria (FeOB) coexisted in anoxic sediments. Geobacter-related FeRB accounted for 5%–31% of the total Bacteria, while Gallionella-related FeOB accounted for only 0.1%–1.3%. A significant correlation between the relative abundance of poorly crystalline Fe and Geobacter spp. suggested that poorly crystalline Fe favored microbial Fe(III) reduction. Poorly crystalline Fe and Geobacter spp. were significantly associated with solid-phase Fe(II) and total inorganic phosphorus levels. Pore water Fe(II) concentrations negatively correlated with NO3–at all sites. We concluded that Geobacter spp. were abundant in the sediments of Lake Donghu, and the redox of Fe might participate in the cycling of nitrogen and phosphorus in sediments. These observations provided insight into the roles of microbial Fe cycling in lake sediments.

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