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Non-targeted and suspect screening analysis using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) holds great promise to comprehensively characterize complex chemical mixtures. Data preprocessing is a crucial part of the process, however, some limitations are observed: (i) peak-picking and feature extraction might be incomplete, especially for low abundant compounds, and (ii) limited reproducibility has been observed between laboratories and software for detected features and their relative quantification. We first conducted a critical review of existing solutions that could improve the reproducibility of preprocessing for LC-HRMS. Solutions include providing repositories and reporting guidelines, open and modular processing workflows, public benchmark datasets, tools to optimize the data preprocessing and to filter out false positive detections. We then propose harmonized quality assurance/quality control guidelines that would allow to assess the sensitivity of feature detection, reproducibility, integration accuracy, precision, accuracy, and consistency of data preprocessing for human biomonitoring, food and environmental communities.

Part of the process to ensure the safety of radioactive waste disposal is the predictive modeling of the solubility of all relevant toxic components in a complex aqueous solution. To ensure the reliability of thermodynamic equilibrium modeling as well as to facilitate the comparison of such calculations done by different institutions it is necessary to create a mutually accepted thermodynamic reference database. To meet this demand several institutions in Germany joined efforts and created THEREDA (Moog et al., 2015). THEREDA is a suite of programs at the base of which resides a relational databank. Special emphasis is put on thermodynamic data along with suitable Pitzer coefficients which allow for the calculation of solubilities in high-saline solutions. Registered users may either download single thermodynamic data or ready-to-use parameter files for the geochemical speciation codes PHREEQC, Geochemist’s Workbench, CHEMAPP, or TOUGHREACT. Data can also be downloaded in a generic JSON-format to allow for the import into other codes. The database can be accessed via the world wide web: www.thereda.de. Prior to release, the released part of the database is subjected to many tests. Results are compared to results from earlier releases and among the different codes. This is to ensure that by additions of new and modification of existing data no adverse side effects on calculations are caused. Furthermore, our website offers an increasing number of examples for applications, including graphical representation, which can be filtered by components of the calculated system. References Moog, H. C., Bok, F., Marquardt, C. M., and Brendler, V.: Disposal of Nuclear Waste in Host Rock formations featuring high-saline solutions - Implementation of a Thermodynamic Reference Database (THEREDA). Appl. Geochem., 55, 72-84, DOI: 10.1016/j.apgeochem.2014.12.016, 2015.

The uptake of niobium by hardened cement paste (HCP) a calcium silicate hydrate (C-S-H) phases was investigated with ⁹³Nb and ⁹⁵Nb (t₁/₂=35.0 days). Structural materials used in nuclear reactors as well as cements contain the naturally occurring isotope ⁹³Nb, while radioactive ⁹⁴Nb with t₁/₂=2×10⁴ years is relevant in the context of nuclear waste disposal. Strong uptake of Nb was observed for both materials, confirming that C-S-H are the main sink of Nb in cement. Isotopic exchange with ⁹³Nb in cement can play a role in the uptake of ⁹⁴Nb under repository conditions. The formation of complexes with isosaccharinic acid (ISA) decreases the Nb uptake, although sorption remains strong up to [ISA]tot=0.1 M. Chloride has a negligible effect on the uptake of Nb up to [NaCl] = 2 M. This work provides a sound basis for the quantitative description and mechanistic understanding of ⁹⁴Nb retention in L/ILW repositories.

This dataset is a report about gamma spectroscopy measurement of the irradiated cyclotron target generated by GammaVision software (ORTEC/AMETEK, Version 8.00.03).

The isotope 94 of niobium (t1/2= 2.04·104 a) is produced during the operation of nuclear reactors due to the neutron activation of 93Nb, which is present in some structural components in nuclear reactor vessels. Related waste streams will be disposed of in repositories for low and intermediate level wastes (L/ILW), where cement is widely used for the stabilization of the waste and for construction purposes. The retention of niobium by young cement was investigated in a series of sorption experiments using a combination of active (95Nb + 91mNb) and inactive (93Nb) niobium isotopes. Sorption experiments assessed also the impact of iso-saccharinic acid (ISA, main degradation product of cellulose) and chloride on Nb retention, both expected in specific L/ILW. A pyrochlore-structure Ca-Nb(V) oxide was found to control the solubility of Nb(V) in cement pore water at pH= 13.5, defining [Nb(V)]aq = 2∙10-6 - 7·10–8 M. Sorption experiments revealed a strong uptake of Nb(V) by cement (5 ≤ log Rd ≤ 7, Rd in L·kg–1), in spite of the predominance of anionic hydrolysis species in the cement pore water. Sorption isotherms were found to be linear within 10–14 M ≤ [Nb(V)]aq ≤ 10–9 M. Calcium silicate hydrate (C-S-H) phases are defined as main sink of Nb(V) in cement, with Ca2+ playing a key role in bridging the negatively charged Nb(V) species to C-S-H. ISA significantly decreases the uptake of Nb(V) at [ISA]aq ≥ 10–4 M, reflecting the formation of stable (Ca-)Nb(V)-ISA complexes in the aqueous phase. Sorption is not affected by chloride within the investigated concentration range (10–5 M ≤ [Cl–] ≤ 1.0 M). This work represents the first experimental evidence on the uptake of niobium by young cement in the absence and presence of ISA and Cl–, thus providing key inputs for the assessment of 94Nb retention in the

Part of the process to ensure the safety of radioactive waste disposal is the predictive modeling of the solubility of all relevant toxic components in a complex aqueous solution. To ensure the reliability of thermodynamic equilibrium modeling as well as to facilitate the comparison of such calculations done by different institutions it is necessary to create a mutually accepted thermodynamic reference database. To meet this demand several institutions in Germany joined efforts and created THEREDA 15 (Moog et al., 2015). THEREDA is a suite of programs at the base of which resides a relational databank. Special emphasis is put on thermodynamic data along with suitable Pitzer coefficients which allow for the calculation of solubilities in high-saline solutions. Registered users may either download single thermodynamic data or ready-to-use parameter files for the geochemical speciation codes 20 PHREEQC, Geochemist’s Workbench, CHEMAPP, or TOUGHREACT. Data can also be downloaded in a generic JSON-format to allow for the import into other codes. The database can be accessed via the world wide web: www.thereda.de Prior to release, the released part of the database is subjected to many tests. Results are compared to results from earlier releases and among the different codes. This is to ensure that by additions of new and modification of existing data no adverse side 25 effects on calculations are caused. Furthermore, our website offers an increasing number of examples for applications, including graphical representation, which can be filtered by components of the calculated system. References Moog, H. C., Bok, F., Marquardt, C. M., and Brendler, V.: Disposal of Nuclear Waste in Host Rock formations featuring high-saline solutions - Implementation of a Thermodynamic Reference Database (THEREDA). Appl. Geochem., 55, 72-84, doi: 30 10.1016/j.apgeochem.2014.12.016, 2015.

Part of the process to assess the safety of disposal sites for radioactive or chemical-toxic waste is the predictive modeling of the solubility of hazardous components in a complex aqueous solution. To ensure the reliability of thermodynamic equilibrium modeling as well as to facilitate the comparison of such calculations done by different institutions it is necessary to create a mutually accepted thermodynamic reference database. To meet this demand in Germany several institutions joined efforts and created THEREDA. It contains a relational databank whose structure was designed in a way that promotes internal consistency of thermodynamic data. It serves as back end to a variety of supplementary programs which allow for adding, editing, and extracting subsets of data. Data considered cover the needs of Gibbs Energy Minimizers and Law-of-Mass-Action programs alike. Interaction parameters for an arbitrary number of mixed phases and p,T-functions of thermodynamic data may also be entered. At present, Pitzer- and SIT-parameters for the aqueous phase are considered. To enhance public use THEREDA is accessible via internet.