scholarly journals Rare earth elements (REE) in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic

2017 ◽  
Author(s):  
Gwyneth Anne MacMillan ◽  
John Chételat ◽  
Joel Heath ◽  
Raymond Mickpegak ◽  
Marc Amyot
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Canadian Arctic ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Carbon And Nitrogen ◽  
Northern Regions ◽  
Order Of Magnitude ◽  
Mining Projects ◽  
Eastern Canadian Arctic

ABSTRACTFew ecotoxicological studies exist for rare earth elements (REEs), particularly field-based studies on their bioaccumulation and food web dynamics. REE mining has led to significant environment impacts in several countries (China, Brazil, U.S.), yet little is known about the fate and transport of these contaminants of emerging concern. To understand how REEs behave in pristine northern food webs, we measured REE concentrations and carbon and nitrogen stable isotope ratios (∂15N, ∂13C) in biota from marine, freshwater, and terrestrial ecosystems of the eastern Canadian Arctic (N=339). Northern ecosystems are potentially vulnerable to REE enrichment from prospective mining projects at high latitudes. Wildlife harvesting and tissue sampling was partly conducted by local hunters through a community-based monitoring project. Results show that REE generally follow a coherent bioaccumulation pattern for sample tissues, with some anomalies for redox-sensitive elements (Ce, Eu). Highest REE concentrations were found at low trophic levels, especially in vegetation and aquatic invertebrates. Terrestrial herbivores, ringed seal, and fish had low REE levels in muscle tissue (<0.1 nmolg-1), yet accumulation was an order of magnitude higher in all liver tissues. Age- and length-dependent REE accumulation also suggest that REE uptake is faster than elimination for some species. Overall, REE bioaccumulation patterns appear to be species- and tissue-species, with limited potential for biomagnification. This study provides novel ecotoxicological data on the behaviour of REE in ecosystems and will be useful for environmental impact assessment of REE enrichment in northern regions.

scholarly journals Rare earth elements in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic

2017 ◽  
Vol 19 (10) ◽  
pp. 1336-1345 ◽  
Author(s):  
Gwyneth Anne MacMillan ◽  
John Chételat ◽  
Joel P. Heath ◽  
Raymond Mickpegak ◽  
Marc Amyot
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Canadian Arctic ◽  
Terrestrial Ecosystems ◽  
Eastern Canadian Arctic

Rare earth elements show consistent bioaccumulation patterns yet limited biomagnification in remote northern ecosystems.

Lattice Location and Luminescence Behavior of Rare Earth Elements Implanted in GaN

1997 ◽  
Vol 482 ◽  
Author(s):  
M. Dalmer ◽  
M. Restle ◽  
A. Stötzler ◽  
U. Vetter ◽  
H. Hofsäss ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Room Temperature ◽  
Lattice Location ◽  
Isochronal Annealing ◽  
Line Intensities ◽  
Order Of Magnitude ◽  
Photoluminescence Studies ◽  
Luminescence Behavior ◽  
Emission Channeling

AbstractSingle crystalline GaN-layers were implanted with radioactive 167Tm and 169yb ions, and their lattice sites were determined using the emission channeling technique. After the decay of 167Tm to 167Er, photoluminescence studies were performed. Upon room temperature implantation, rare earth atoms immediately occupy relaxed substitutional sites with an average relaxation of about 0.025 nm. Isochronal annealing treatments up to 800 °C and co-implantation of oxygen to a dose an order of magnitude greater than that of the Tm or Yb do not influence the rare earth lattice sites. A variety of different rare earth related luminescence lines are observed, and co-implantation of oxygen strongly changes the line intensities.

scholarly journals Distribution of rare-earth elements in rock-forming minerals of corundum-bearing rocks of the Khitoostrov deposit (North Karelia)

2021 ◽  
Vol 66 (4) ◽  
Author(s):  
Ekaterina Yu. Akimova ◽  
◽  
Sergey G. Skublov ◽  
◽  
◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Isotopic Composition ◽  
Mobile Belt ◽  
Positive Slope ◽  
Rock Formation ◽  
Ree Distribution ◽  
Lree Enrichment ◽  
Order Of Magnitude ◽  
The Difference

The distribution of rare-earth elements (SIMS method) in minerals from the rocks of the Khitoostrov occurrence (Belomorian mobile belt of Eastern Fennoscandia) was studied: corundum-bearing metasomatites with anomalous isotopically light oxygen and hydrogen and garnet amphibolites after gabbro with normal isotopic composition. The study was accompanied by estimates of P-T parameters of rock formation using multi-equilibrium thermobarometry (TWEEQU method). Temperatures calculated for garnet amphibolites after gabbro fall within the range of 730–770 ° C, pressures - 13–14 kbar; for corundum-bearing rocks, temperatures were 680–710 ° C, pressures - 6.5–7.5 kbar. Corundum-bearing rocks were formed at slightly lower temperatures and at significantly lower pressures than garnet amphibolites after gabbro. The REE distribution spectra in garnets from apogabbroic amphibolites are characterized by a clearly pronounced slope from light to heavy REE, while in garnets from corundum-bearing rocks they have a less pronounced positive slope, which is associated with a noticeable enrichment of garnets in LREE and an insignificant depletion of HREE. Calcium amphiboles from corundum-bearing rocks are significantly enriched in rare-earth elements as compared to amphiboles from garnet amphibolites after gabbro, especially LREE (by more than an order of magnitude) and, to a lesser extent, MREE. Plagioclases from corundum-bearing rocks are also enriched in LREE against the background of garnet amphibolites. Thus, in all the studied minerals of corundum-bearing rocks LREE enrichment is recorded. It isn’t manifested in the minerals of amphibolites and, obviously, isn’t related to the difference in P-T parameters of rock formation. Consequently, LREE was transferred by a specific fluid during mineral-forming processes, which led to the formation of metasomatites with an anomalous isotopic composition of oxygen and hydrogen.

Rare-earth elements in soil and pine needle from northern terrestrial ecosystems

1997 ◽  
Vol 219 (1) ◽  
pp. 105-110 ◽  
Author(s):  
V. F. Peresedov ◽  
S. F. Gundorina ◽  
T. M. Ostrovnaya
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Terrestrial Ecosystems ◽  
Pine Needle

scholarly journals Ecological/economical Assessment of Pit Waters (the Ural Copper Pyrite Watersealed Mines as a Study Case)

2016 ◽  
pp. 52
Author(s):  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Water Discharge ◽  
Water Bodies ◽  
Raw Material ◽  
Environmental Damage ◽  
Ferrous Metals ◽  
Order Of Magnitude ◽  
Copper Pyrite ◽  
Non Ferrous Metals

Worked-out copper pyrite mines are one of the considerable sources of hydrosphere pollution. Analysis of components of the environmental damage to surface water bodies due to treated pit water discharge has been carried out. Environmental damage to water bodies caused by the Levikha and Degtyarsk mines pit water discharge both during the mines operation and after watersealing of them is assessed in 100–200 million rubles per year? And the value of the prevented environmental damage is one order of magnitude higher. Individual components contribution to environmental damage has been determined: during the mines operation cooper was the main pollutant, after the pumping termination zinc became the main pollutant. It has been stated that pit water is a reliable renewable source of non-ferrous metals and rare earth elements and can be considered a hydro/mineral raw material deposit. Commercial content of non-ferrous metals and rare earth elements in the watersealed copper pyrite mines has been estimated. Total recoverable value of non-ferrous metals and rare earth elements in the Levikha mine pit water exceeds 4 million US dollars per year. Rare earth elements comprise the main share. It has been shown that potential recoverable value of the components exceeds cost of annual neutralization of acidic pit water and the value of environmental damage caused by the treated pit water discharge.

The distribution pattern of Rare Earth Elements (REE) in Vitis vinifera L. discriminates the substrate of growth ?

2020 ◽  
Author(s):  
Marcella Barbera ◽  
Pierpaolo Zuddas ◽  
Filippo Saiano
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Vitis Vinifera ◽  
Distribution Pattern ◽  
Vitis Vinifera L ◽  
Experimental Conditions ◽  
Plant Parts ◽  
Aerial Parts ◽  
Order Of Magnitude ◽  
Leaves And Roots

&lt;p&gt;Rare Earth Elements (REE) have been employed to stimulate the plant growth in national and international strategies while their role still remains controversial as the process involved in soil-plant system is not completely understood yet. &amp;#160;&lt;/p&gt;&lt;p&gt;In this study we have investigated the effect of REE amount in the substrate during the Vitis vinifera L growth analysing the REE distribution in the different part of the plants. Experiments were carried out over 1 year using two different substrates: one with a &quot;natural&quot; substrate (blank experiments) and another using the same substrate artificially enriched by an equimolar solution of REE (spiked experiments).&lt;/p&gt;&lt;p&gt;We found that both plant mass and amount of REE in leaves are both not influenced by the substrate enrichment. However, roots are by 1 order of magnitude enriched in REE for the 3 orders of magnitude enriched substrate of growth. This indicates that Vitis vinifera L. does not significantly transfer REE into the aerial parts during growth while identify roots as the plant critical parts responsible for the filtering of the environmental stress.&amp;#160; Plotting the REE normalized distribution for every element, the different experimental conditions can be significantly discriminated: under spiked substrate conditions, REE normalised distribution shows a &amp;#8216;zig zag&amp;#8217; pattern in both leaves and roots. We propose that the REE normalised distribution pattern measured in the different plant parts (leaves and roots) can be used to discriminates the conditions of substrate characteristics during the vitis vinifera growth. Acting as natural tracers, the REE normalised distribution could be potentially used as tool tracing the substrate origin of the Vitis vinifera plant.&amp;#160;&lt;/p&gt;

scholarly journals Analysis of Impact Assessment Practice and Mitigation for Shipping Activity in the Eastern Canadian Arctic

ARCTIC ◽  
2020 ◽  
Vol 73 (2) ◽  
pp. 221-239
Author(s):  
Bethany Thiessen ◽  
Bram Noble ◽  
Kevin Hanna
Keyword(s):  
Impact Assessment ◽  
Canadian Arctic ◽  
Tourism Industry ◽  
Mitigation Strategies ◽  
Cumulative Effects ◽  
The Arctic ◽  
Assessment Practice ◽  
Marine Traffic ◽  
Mining Projects ◽  
Eastern Canadian Arctic

Marine traffic is increasing in the Canadian Arctic, largely because of changing ice conditions, a growing tourism industry, and natural resource extraction. Impact assessment (IA) is a primary instrument for managing the impacts of project development in the Arctic, but there has been limited analysis of the scope and application of IA for identifying and managing the impacts of shipping. This paper examines the impacts of shipping activity associated with mining projects in the eastern Canadian Arctic, including barge traffic and resupply vessels; the mitigation actions commonly prescribed in IA; and the key IA challenges facing decision-makers. Results show 71 impacts that may be considered common to IA applications for shipping, for which the mitigation strategies rely heavily on compliance-based measures and “best” practices to either minimize or avoid impacts, supported by follow-up programs that provide for adaptation of mitigation based on monitoring results. However, results also illustrate concerns over the ability of IA to effectively manage the cumulative effects of increasing Arctic marine traffic. Only a minority of projects involving marine transport trigger IA, even though other types of marine traffic, such as tourism, may generate similar types of impacts. The common impacts and mitigation solutions identified in this research and the lessons from monitoring can inform future IAs for shipping, improve permitting processes for shipping activities that do not require IA, and provide a foundation for a more regional or sector-wide approach to identifying and mitigating the cumulative effects of increasing vessel traffic.

scholarly journals The Eastern Canadian Arctic at ca. 6 ka BP: A Time of Transition

2007 ◽  
Vol 49 (1) ◽  
pp. 13-27 ◽  
Author(s):  
Kerstin M. Williams ◽  
Susan K. Short ◽  
John T. Andrews ◽  
Anne E. Jennings ◽  
William N. Mode ◽  
...  
Keyword(s):  
Canadian Arctic ◽  
Thermal Inertia ◽  
Water Structure ◽  
Terrestrial Ecosystems ◽  
The Arctic ◽  
Water Volume ◽  
Baffin Island ◽  
East Greenland ◽  
Middle Holocene ◽  
Eastern Canadian Arctic

ABSTRACT The middle Holocene was a time of definite environmental transition in the Eastern Canadian Arctic. Based on several proxy indicators (pollen, diatoms, foraminifera, molluscs and nearshore sedimentation rates), it appears that a thermal maximum occurred around middle Holocene (6-4 ka), several thousand years after the insolation maximum — a lag caused by the thermal inertia of the earlier massive ice sheet. Terrestrial records indicate that a warming began around 6 ka, both in the subarctic (Labrador - Ungava) and on Baffin Island. Marine records, on the other hand, suggested major water structure changes around 6 ka both in the Northeastern Canadian Arctic and also along the East Greenland coast with evidence of a marine surface water temperature maximum at 8 ka. We hypothesize that the marine circulation changes, both along the Baffin Island and along the East Greenland coasts, were primarily driven by glacio-isostatic uplift of the Arctic Channels. With the cessation of water flow of Atlantic (warmer) origin, and decrease in water volume from the deeper parts of the Arctic Ocean through the Arctic Channels, the export through the Fram and Denmark straits increased and the water column changed. Changes in the concentration and duration of sea ice along the eastern Canadian coast would have had important repercussions on the biota of the coastal marine and terrestrial ecosystems.

scholarly journals Accumulation and fractionation of rare earth elements are conserved traits in the Phytolacca genus

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nicolas Grosjean ◽  
Marie Le Jean ◽  
Charlotte Berthelot ◽  
Michel Chalot ◽  
Elisabeth Maria Gross ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Contaminated Soils ◽  
Lateral Roots ◽  
Emerging Pollutants ◽  
Contaminated Sites ◽  
Phytolacca Americana ◽  
Related Information ◽  
Order Of Magnitude ◽  
Hyperaccumulating Plant

AbstractRare earth elements (REEs) are now considered emerging pollutants in the environment. Phytolacca americana, an REE hyperaccumulating plant, has been proposed for the remediation of REE-contaminated soils. However, there is no REE-related information for other Phytolacca species. Here, we examined five species (P. americana, P. acinosa, P. clavigera, P. bogotensis, and P. icosandra) for their response to REEs. REE accumulation and fractionation traits both occurred on the same order of magnitude among the five species. Heavy REEs were preferentially transferred to leaves relative to light REEs. Regardless of the species, lateral root length and chlorophyll content decreased under REE exposure, and lateral roots and foliar anthocyanins increased. However, plants did not experience or only slightly experienced oxidative stress. Finally, REE exposure strongly modulated the ionome of roots and, to a lesser extent, that of leaves, with a negative correlation between REE and Mn contents. In conclusion, our study provides new data on the response of several Phytolacca species to REEs. Moreover, we highlighted that the REE accumulation trait was conserved among Phytolacca species. Thus, we provide valuable information for the phytoremediation of REE-contaminated sites since the most appropriate Phytolacca species could be selected depending on the climatic/pedological area to be remediated.

Characterization of Magneto-Optical Rare Earth-Doped Ingaasp Thin Films on InP

1995 ◽  
Vol 392 ◽  
Author(s):  
B. J. Stadler ◽  
K. Vaccaro ◽  
A. Davis ◽  
E. A. Martin ◽  
G. O. Ramseyer ◽  
...  
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Integrated Circuits ◽  
Rare Earth Elements ◽  
Optical Systems ◽  
Order Of Magnitude ◽  
Device Applications ◽  
Er Doped ◽  
Rare Earth Doped ◽  
The Rare Earth

AbstractWe have investigated the properties of rare earth-doped InGaAsP thin films with special interest in magneto-optical device applications. Magneto-optical properties have been used in optical systems as isolators, waveguides, and switches. These materials and devices can be used to expand the functionality of InP opto-electronic integrated circuits (OEICs). Thin films of InP, InGaAs, and InGaAsP, grown by liquid phase epitaxy, were lattice matched to the (100) InP substrates. The films were n-type, with the carrier concentration decreasing by an order of magnitude in the doped films due to gettering by the rare earth elements. The doped films contained 2.6×1018 - 1.5×1020 cm−3 rare earth elements, which were observed to segregate toward the film/melt interface in the more highly doped films. A broad photoluminescence was observed at 1.52 μm in the Er-doped films. The Verdet constant was measured through the sample thickness, and the substrate signal dominated the measurements. However, the measured values were in agreement with published values for InP, which gives an indication of the films' host value. The Verdet constants increased from 4 to 7 deg/T/mm as the wavelength decreased toward the band edge. The band edges of our samples were 0.93, 1.62, and 1.30 μm, respectively. Rare earth dopants were observed to raise the refractive index of the InP films, and waveguiding at 1.3 μm was achieved in the rare earth-doped InP films and in the InGaAsP films.

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