Conference Agenda

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Session Overview
1.7-2 Critical Metals in the Environment
Tuesday, 21/Sept/2021:
1:30pm - 3:00pm

Session Chair: David M. Ernst, Jacobs University Bremen
Session Chair: Franziska Klimpel, Jacobs University Bremen
Session Chair: Dennis Krämer, Jacobs University Bremen
Session Chair: Anna-Lena Zocher, Jacobs University Bremen

Session Abstract

In the past years, certain trace elements hitherto only used as geochemical proxies have gained increasing societal and economic importance due to their restricted and insecure supply and high importance for high-tech applications such as enabling technologies. These critical metals are now included in the list of critical raw materials, published by the EU in 2020. Critical metals are, for example, the rare earth elements and the platinum group elements, but also more “exotic” ones like antimony, gallium, germanium, hafnium, indium, scandium, tantalum, tungsten and vanadium.Although the increasing application of these metals results in a growing input from anthropogenic sources into the environment, knowledge of their environmental behaviour, their bioavailability and their (eco)toxicity are still in their infancy. This limited knowledge is partly caused by the fact that many of these metals occur at very low concentrations in the natural environment, posing additional analytical challenges.This session collects contributions related to critical high-technology metals in the environment, especially, but not limited to, studies on a) their analytical determination in various matrices, also including analysis of plant and animal tissues, b) their geochemical behaviour in Earth’s surface systems, i.e. the critical zone, c) their anthropogenic input, d) studies on bioavailability and (eco)toxicity, and e) rehabilitation of contaminated sites. We especially welcome contributions from Early Career scientists and from the EU Innovative Training Network "PANORAMA” (euroPean trAining NetwOrk on Rare eArth elements environMental trAnsfer: from rock to human).

1:30pm - 1:45pm

The antiquity of lanthanide tetrad effect and super-chondritic Y/Ho ratio in seawater

David M. Ernst, Michael Bau

Jacobs University Bremen, Germany

Pure and pristine Archaean and Palaeoproterozoic banded iron formations (BIFs) are excellent marine geochemical archives, especially of original rare earths and yttrium (REY) characteristics. As recently demonstrated for the Mt.Ruker BIF in Antarctica[1], ultrapure BIFs preserve seawater-like REY distribution with heavy REYSN enrichment and light REYSN depletion (SN: shale-normalized). Our results indicate that a prominent feature of the REY signature of seawater throughout Earth’s history has been a super-chondritic Y/Ho ratio which falls between that of potential detritus and the maximum Y/Ho ratio of modern seawater. Another more subtle and fragile proxy of modern seawater is the W-type lanthanide tetrad effect (LTE) which results from the slightly differing bonding characteristics of individual REY in chemical complexes, due to the specific electron configuration of the REY3+ ions. This W-type LTE is found in pure marine carbonate rocks and in BIFs, and confirms the primary and marine origin of their REY distribution. The preservation of uniform, super-chondritic Y/Ho ratios in combination with the W-type LTE in chert and Fe-oxide BIF bands is an excellent tool to test the pristineness of geochemical signals in such samples as well as evidence for the primary origin of banding in BIFs.

[1] Ernst D. M. and Bau M. (2021) Banded iron formation from Antarctica: The 2.5 Ga old Mt. Ruker BIF and the antiquity of lanthanide tetrad effect and super-chondritic Y/Ho ratio in seawater. Gondwana Research 91, 97–111.

1:45pm - 2:00pm

Toxicological effects of rare earth elements to photosynthetic organisms

Edith Padilla Suárez1, Antonietta Siciliano1, Marco Guida1,2, Giovanni Pagano2, Marco Trifuoggi3, Sara Serafini1, Emilia Galdiero1, Franca Tommasi4, Giusy Lofrano2, Isidora Gjata4, Antonios Apostolos Brouziotis1,3, Renato Liguori4, Giovanni Libralato1

1Department of Biology, University of Naples Federico II; 2Centro Servizi Metrologici e Tecnologici Avanzati (CeSMA); 3Department of Chemical Sciences, University of Naples Federico II; 4Department of Biology, Università degli Studi di Bari Aldo Moro

Rare earth elements (REEs) have become a key component in many technological applications. Due to the rapid increase in their use, the potential environmental exposure has also expanded. However, the effects on the ecosystem have not been yet thoroughly evaluated, leaving many knowledge gaps. To evaluate the effects of REEs, a set of experiments with acute and chronic exposure were performed on photosynthetic organisms.

The effects of acute exposure of four elements (cerium, gadolinium, lanthanum and neodymium) in two set upsexperimental scenarios with different pH values (6 and 4), was evaluated on three testing species: Raphidocelis subcapitata, Lepidium sativum and Vicia faba. In the rResults obtained in the acute exposure, a higher toxicity at pH 4 was observedindicated higher toxicity levels, which could be explained by a higher bioavailability of the elements. From the relative calculated median effective concentrations (EC50s), R. subcapitata was the most sensitive species, followed by L. sativum and lastly, V. faba.

Further investigations focused on , the chronic exposure of lanthanum and cerium was evaluated on Raphidocelis subcapitata. After a 28 days exposure, results showed a growth inhibition effects effect and increasing a bioaccumulation (from day 7 to 28) with effect at the end of the test. Moreover, endpoints regardedfluctuating values of the relative as biomarkers of stress (ROS, CAT, and SOD)., fluctuated during the sampling days during the exposure (day 7, 14, 21 and 28).

2:00pm - 2:15pm

Spatial and temporal patterns of rare earth elements in the seaweed Saccarina latissima along the Norwegian coast

Stefania Piarulli1, Tomasz Ciesielski2, Silje Forbord3, Achilleas Zevros2, Bjørn Henrik Hansen1, Bjørn Munro Jenssen2, Julia Farkas1

1Department of Climate and Environment, SINTEF Ocean, Brattørkaia 17C, 7010 Trondheim, Norway;; 2Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491, Trondheim, Norway;; 3Department of fisheries and new biomarine industry, SINTEF Ocean, Brattørkaia 17C, 7010 Trondheim

Rising rare earth elements (comprising the 15 lanthanoids plus yttrium (REY)) processing and use can lead to increased anthropogenic REY release into the environment, representing a potential environmental concern. Seaweeds due to their key ecological role as primary producers, habitat forming organisms and their tendency to accumulate metals have been largely used for monitoring anthropogenic pollution in coastal areas. In this study we assessed REY contents in Saccarina latissima seaweed to identify potential anthropogenic REY sources, and to relate accumulation patterns to different local abiotic and biotic conditions, including light regime, salinity, temperature and nutrient concentrations which can change over space and time. S. latissima specimens were collected at 2 depths (1-2 m and 8-9 m) in 4 locations at 4 time points (from May to August) along the Norwegian coastline over a germinating season. REY concentrations were analysed in freeze dried samples, each constituted by a pool of 10 specimens, with ICP-MS and relations between seaweed and REY accumulation, growth and protein contents were evaluated. Results provided in this study are expected to deepen the knowledge of the environmental bioavailability and accumulation patterns of REY along a spatial and temporal environmental gradient.

2:15pm - 2:30pm

Ecotoxicological effects of rare earth elements on early life stages of fish

Stefania Piarulli1, Bjørn Henrik Hansen1, Frida Fossum2, Florence Kermen2, Bjarne Kvæstad3, Pål A. Olsvik4, Julia Farkas1

1Department of Climate and Environment, SINTEF Ocean, 7010 Trondheim, Norway;; 2Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway; 3Department of fisheries and new biomarine industry, SINTEF Ocean, Brattørkaia 17C, 7010 Trondheim; 4Faculty of Biosciences and Aquaculture, Nord University, N-8049 Bodø, Norway;

Rare earth elements, comprising the 15 lanthanoids (LN; IIIb in the Periodic Table) plus yttrium are critical elements for a wide range of applications, including new and traditional industries as renewable energy, automotive industries, metallurgy as well as agriculture and medical diagnostics. Rising REY production and use can lead to an increased release into the environment and represents a potential environmental concern. However, the bioavailability and effects of REY and anthropogenic REY-chemical complexes (ACC-REY) remain significantly understudied in aquatic organisms.Here, we evaluated the impact of different REY and ACC-REY on early life stages of two fish species: zebrafish (Danio rerio) as freshwater model species and cod (Gadus morhua) as marine species. Fish embryos were exposed to nominally 2000, 200, 20, 2 and 0.2 µg L-1 of different REY compounds. Mortality, hatching, larvae development and morphometry were monitored. At the end of the exposure, a subsample of larvae from each treatment was subjected to image analyses to evaluate larvae mobility and behaviour. These individuals were thereafter analysed immunohistochemically to investigate REY impacts on neural activity. First results showed increased mortality and larvae deformation at higher REY concentrations. Further, transcriptomic responses are analysed to reveal underlying molecular effect mechanisms and affected pathways. Results from this study will provide knowledge on the eco-toxicological risks associated to increasing REY release into aquatic ecosystems.

2:30pm - 2:45pm

Release of beryllium (Be) and tungsten (W) from historical mine tailings and the environmental impact on epilithic water diatoms in downstream surface water

Lina Hällström

Luleå University Of Technology, Sweden

There is a potential risk that geochemical cycles of critical metals (e.g Be and W) will be affected in the pristine environment, when mining of these metals increases to meet the demand in green technology. To understand their geochemical behavior and environmental impact are of high importance to ensure a sustainable development of mine waste and water management. Beryllium and W are identified as elements of potential concern that can have adverse impact on humans and ecosystems. The release of Be and W from two historical skarn tailings (Smaltjärnen and Morkulltjärnen repositories) from the same ore body (Yxsjöberg/Sweden), and the impact on epilithic water diatoms in downstream neutral surface water were studied. Dissolved Be had been released in high concentrations from danalite (Be3(Fe4.4Mn0.95Zn0.4)(SiO4)3.2S1.4) due to oxidation and acidifications in tailings stored open to the atmosphere (Smaltjärnen). Tungsten was released in low concentrations as an indirect consequence of sulfide oxidation. Thus, CO32- released from calcite buffering the acid produced had exchange with WO42- on scheelite (CaWO4) surfaces. High concentrations of dissolved W were present downstream the covered and water saturated tailings (Morkulltjärnen). Beryllium and W are considered as immobile elements, but both were transported in neutral mine drainage (NMD) >5 km downstream the mine site. The water quality from both repositories had negative impact on epilithic water diatoms >2 km from the site. This study shows the importance to understand the geochemistry and mineralogy before choosing remediation method for mine tailings enriched in critical metals, and the need to study NMD.

2:45pm - 3:00pm

Scandium and Rare Earths in Major Rivers in Sweden

Franziska Klimpel, Michael Bau

Jacobs University Bremen, Germany

Scandium (Sc) is often included in the group of rare earths and yttrium (REY), but in contrast to the REY, knowledge on its behaviour in the hydrosphere is rather limited. However, a better understanding of the distribution and behaviour of Sc is important, as its use in industry is expected to grow exponentially in future, which will likely result in an increasing Sc release into the environment.

Here, we report and discuss Sc and REY data for the “dissolved fraction” (<0.2 µm) from twelve pristine rivers in Sweden sampled in May 2019. All rivers are characterised by low conductivity (18-60 µS/cm2), slightly acidic to neutral pH (6.04-7.11) and elevated dissolved organic carbon (DOC) concentrations (5.50-10.3 mg/L). Their shale-normalised REY patterns show a slight enrichment of heavy REY (HREY) compared to light REY (LREY), and negative Ce and positive Y anomalies. Some rivers also show a negative Eu anomaly. The REY distribution in these rivers is controlled by nanoparticles and colloids (NPCs) present in the dissolved fraction. Compared to data from 2014, all rivers show higher REY concentrations and a slightly lower HREY enrichment, suggesting a higher NPCs content in the rivers in 2019. Scandium concentrations vary between 0.363nM and 1.17nM and increase with increasing DOC and Fe concentrations. This suggests that Sc has a strong affinity for NPCs, similar to the REY. The association of Sc with DOC further suggests a significant impact of organic ligands on the behaviour of Sc in the hydrosphere.