1. Method development and production of an ambient-stable blood certified reference material for total mercury, methylmercury, and trace elementsKoichi Haraguchi, Mineshi Sakamoto, Hiromitsu Nagasaka, Milena Horvat, Ermira Begu, Polona Klemenčič, Adna Alilović Osolin, Masaaki Nakamura, 2026, original scientific article Abstract: Background. Certified reference materials (CRMs) for mercury speciation of biological fluids have hitherto been limited to frozen or cold-storage types, which impedes the participation of laboratories in tropical or remote regions. Existing CRMs often do not fully meet user needs, particularly regarding storage stability and concentration relevance. Results. Using pooled Japanese human blood, we developed a freeze-dried, ambient-stable blood CRM, with certified values of 6.16 μg L−1 for total mercury (THg) and 5.46 μg L−1 for methylmercury (MeHg, as Hg). These concentrations are congruent with median exposure levels in fish-consuming populations (e.g., small island states and riverine Amazonian communities) derived from global biomonitoring data. Homogeneity, stability, and traceability were validated through inter-laboratory comparisons and rigorous uncertainty assessment. Significance. This ambient-stable blood CRM broadens global access to high-quality QA/QC of mercury speciation, especially in regions lacking cold-chain infrastructure. It contributes to capacity building under the Minamata Convention and strengthens interlaboratory comparability. Registration in COMAR and international collaborative deployment are under active development, enhancing the global infrastructure for mercury biomonitoring.
Keywords: passive monitoring, methylmercury, blood samples, mercury detection, human biomonitoring, trace elements
Published in DiRROS: 04.05.2026; Views: 183; Downloads: 152
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2. Sustainable mercury monitoring using graphitic carbon nitride as a 2D binding layer in diffusive gradient thin filmsDmitrii Deev, Raghuraj S. Chouhan, Igor Živković, Ermira Begu, Ana Drinčić, Francisco Ruiz-Zepeda, Andraž Krajnc, Ivan Jerman, Roman Viter, Aleš Lapanje, Milena Horvat, 2026, original scientific article Abstract: Mercury (Hg) is a highly toxic and persistent environmental pollutant whose accurate monitoring remains challenging due to limitations in existing diffusive gradients in thin films (DGT) binding materials, including insufficient selectivity, complex synthesis, and sustainability concerns. In this study, we report the first application of graphitic carbon nitride (GCN) nanosheets as a metal-free and sustainable binding material for Hg²⁺ monitoring in DGT systems, addressing key limitations of current approaches. Few-layer GCN nanosheets were synthesized via thermal polymerization followed by protonation-assisted exfoliation and comprehensively characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy, and scanning electron microscopy (SEM). These analyses confirmed the formation of a structurally stable, nitrogen-rich framework with abundant coordination sites. The GCN–agarose (AG–GCN) composite binding layer demonstrated high mercury binding efficiency (>90%) at environmentally relevant concentrations (2.5–10 ng/mL) and near-neutral pH, attributed to strong coordination between Hg²⁺ ions and electron-donating nitrogen sites within the heptazine structure. Compared to conventional DGT binding phases, the proposed system offers enhanced sustainability, metal-free composition, and strong affinity toward mercury, highlighting its potential for next-generation passive environmental monitoring and advanced nanomaterial-based sensing platforms.
Keywords: passive monitoring, graphitic carbon nitride nanosheets, adsorbent, mercury detection, nanosheets
Published in DiRROS: 04.05.2026; Views: 220; Downloads: 150
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3. The freshwater sounds archiveJack A. Greenhalgh, Mauricio S. Akmentins, Martin Boullhesen, Gabriel Lourenço Brejão, Jacob C. Bowman, Jernej Polajnar, David Stanković, 2025, other component parts Abstract: Freshwater ecosystems are full of underwater sounds produced by amphibians, aquatic arthropods, reptiles, plants, fishes, and methane bubbles escaping from the sediment. Although much headway has been made in recent years investigating the overall soundscapes of various freshwater ecosystems around the world, there remains a significant knowledge gap in our collective inability to accurately and reliably link recorded sounds with the species that produced them. Here, we present The Freshwater Sounds Archive, a new global initiative, which seeks to address this knowledge gap by collating species-specific freshwater sound recordings into a publicly available database. By means of metadata collection, we also present a snapshot of the species studied, the recording equipment, and recording parameters used by freshwater ecoacousticians globally. In total, 61 entries were submitted to the archive between the 4th of March 2023 and the 30th of April 2025, representing 16 countries and 6 continents. The most numerous taxonomic group was arthropods (29 entries), followed by fishes (14 entries), amphibians (10 entries), macrophytes (7 entries), and a freshwater mollusk (1 entry). The majority of the submissions were from European countries (27 entries), of which the United Kingdom was the most represented with 14 entries. The next most represented region was North America (11 entries), followed by South America (8 entries), Oceania and Asia (5 entries each), Africa (3 entries), and the Middle East and Central America with 1 entry each. The global south, polar regions, and areas with an elevation >500 m (asl) were underrepresented. The field of freshwater ecoacoustics to date has largely focused on the analysis of ‘sound types’ due to a current lack of knowledge of species-specific sounds. The Freshwater Sounds Archive presents an opportunity to move beyond the ‘sound type’ approach, and towards an approach with higher taxonomic resolution, ultimately resulting in species-specific descriptions. Furthermore, The Freshwater Sounds Archive will provide freshwater ecoacousticians with one of the main tools required to start creating annotated training datasets for machine learning models from soundscape recordings by referring to known species sounds present in the archive. In the long-term, this will result in the automatic detection and classification of species-specific freshwater sounds from soundscape recordings, such as indicator, invasive, and endangered species.
Keywords: freshwater ecoacoustics, biological archive, biomonitoring, passive acoustic monitoring
Published in DiRROS: 02.07.2025; Views: 896; Downloads: 518
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