1. Human hair certified reference material for total mercury, methylmercury, and trace element analysesAkane Yamakawa, Kimiyo Nagano, Kaoru Onishi, Miyuki Ukachi, Milena Horvat, Adna Alilović Osolin, Polona Klemenčič, Ermira Begu, Marta Jagodic Hudobivnik, Keisuke Uchida, 2025, izvirni znanstveni članek Povzetek: The National Institute for Environmental Studies (NIES) developed the NIES CRM No. 13-a, a new certified reference material for human hair, using scalp hair from Asian females. This CRM represents a significant advancement in support of global mercury exposure assessments and offers unparalleled reliability and scope compared with existing materials. We aimed to provide a comprehensive overview of the preparation, certification, and application of NIES CRM No. 13-a. In total, 806 bottles (3 g each) were produced, with thorough homogenization ensured through sieving and blending. Certified values for total mercury (1.06 ± 0.07 mg/kg), methylmercury (0.858 ± 0.075 mg/kg), and key trace elements (arsenic, cadmium, lead, selenium, and zinc) were determined through extensive collaborative analyses involving 20 laboratories. Additional reference values were provided for calcium, magnesium, sodium, sulfur, antimony, barium, copper, iron, and manganese. Rigorous stability and homogeneity assessments demonstrated the stability of the CRM for over 10 years and consistency across sample units, even for challenging elements such as selenium. The CRM also includes information values of stable mercury isotope ratios, reflecting their growing importance as exposure tracers. This enhancement in accuracy and traceability facilitates accurate mercury and trace element assessments in human hair, enabling improved biomonitoring of mercury exposure, dietary studies, toxicological evaluations, human health risk evaluations, and regulatory compliance.
Ključne besede: metilirano živo srebro, methylmercury, certified reference material
Objavljeno v DiRROS: 05.09.2025; Ogledov: 493; Prenosov: 199
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2. Achieving measurement comparability in mercury speciation analysis in seawater : Key requirements and best practicesIgor Živković, Lars-Eric Heimbürger-Boavida, Mariia V. Petrova, Aurélie Dufour, Ermira Begu, Milena Horvat, 2025, izvirni znanstveni članek Povzetek: The comparability of measurement results is an important issue in contemporary mercury (Hg) speciation in seawater. Sampling campaigns must be properly designed to determine significant differences on spatial and temporal scales, considering two major parameters: the variability of expected data at a given sampling point/ transect and variability in the results due to the intrinsic properties of specific analytical methods, particularly the measurement uncertainty. This study assessed the required sample size, considering several aspects of data variability when determining total Hg, dissolved gaseous Hg, and methylated Hg species in seawater. The required sample sizes were calculated using (1) the measurement uncertainty of a single-laboratory measurement of analytical methods used; (2) performance of the laboratories in interlaboratory comparison exercises; and (3) natural variability in Hg species/fractions in a selected case study in the Central Adriatic Sea. It was shown that the measurement uncertainty of a particular method and interlaboratory variability among laboratories have significant influence on data interpretation in case natural variability of Hg fractions is relatively small, such as for example the open seawater depth profiles. In contrary, in areas with large natural variability of Hg con tractions, such as coastal and contaminated sites, their influence on data interpretation is negligible. The present paper introduces the importance of proper estimation of measurement uncertainty in international programs, such as GEOTRACES, where data comparability is of fundamental importance to assess temporal and spatial trends of Hg measurements in the marine environment
Objavljeno v DiRROS: 05.09.2025; Ogledov: 486; Prenosov: 124
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