Boron isotope ratio (delta B-11) measurements in water framework directive monitoring programs: comparison between double focusing sector field ICP and thermal ionization mass spectrometry

International audienceThe aim of our research was to compare delta B-11 measurements performed with thermal ionization mass spectrometry (TIMS) and sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS) and evaluate the feasibility of implementing stable isotope methods in European water framework directive (WFD) monitoring programs. The comparison was based on delta B-11 measurements of 192 ground-and surface water samples and 15 leachates of nitrate pollution source materials (organic and mineral fertilisers). The precision of delta B-11 measurements attainable with SF-ICP-MS, 2 sigma= +/- 2.6 parts per thousand; (n = 192), is as expected lower than the precision achieved by TIMS, 2 sigma= +/- 0.3 parts per thousand (n=183). However the ease of use, rapidity and availability of SF-ICP-MS on one hand and the observed variability in delta B-11 in ground-and surface water on the other (from -3.4 to +37 parts per thousand), demonstrates that using SF-ICP-MS as an isotopic screening method would promote the use of isotopic methodology for WFD monitoring. Based on the results of the different case studies it is shown that retrieving precise information on the identification of pollution sources from delta B-11 values requires reaching the best analytical precision and accuracy possible. Hence, the superior precision of TIMS advantages tracing of nitrate pollution sources. However for some cases, e. g. trying to decipher contributions between sources with really distinct delta B-11 signatures (e.g. manure and sewage effluent), SF-ICP-MS results lead to the same conclusions and can therefore be used as a first approachable screening method for the determination of delta B-11 in WFD monitoring programs

Strontium isotope geochemistry of alluvial groundwater: a tracer for groundwater resources characterisation

International audienceThis study presents strontium isotope and major ion data of shallow groundwater and river water from the Ile du Chambon catchment, located on the Allier river in the Massif Central (France). There are large variations in the major-element contents in the surface- and groundwater. Plotting of Na vs. Cl contents and Ca, Mg, NO3, K, SO4, HCO3, Sr concentrations reflect water–rock interaction (carbonate dissolution for Ca, Mg, HCO3 and Sr because the bedrock contains marly limestones), agricultural input (farming and fertilising) and sewage effluents (for NO3, K, SO4), although some water samples are unpolluted. Sr contents and isotope ratios (87Sr/86Sr vary from 0.70892 to 0.71180 along the hydrological cycle) in the groundwater agree with previous work on groundwater in alluvial aquifers in the Loire catchment. The data plot along three directions in a 87Sr/86Sr v. 1/Sr diagram as a result of mixing, involving at least three geochemical signatures–Allier river water, and two distinct signatures that might be related to different water-rock interactions in the catchment. Mixing proportions are calculated and discussed. The alluvial aquifer of the Ile du Chambon catchment is considered, within the Sr isotope systematic, in a larger scheme that includes several alluvial aquifers of the Loire Allier catchment. Keywords: : Loire river, major and trace elements, Sr isotopic ratio, alluvial aquifer, hydrolog

Petrological and geochemical characterization of Ge-bearing coals from the eastern Rhodopes, Bulgaria

The coals from Pchelarovo and Vulce Pole are perhydrogenated coals showing high sulphur content (3.2 - 6.2 wt%) and significant Ga and Ge contents (0 - 480 ppm) in organic matter (OM). The coals from Medenbuk could be perhydrogenated coals modified by weathering processes. They show low sulphur content (1.5 wt%), high homogeneous Ge contents in OM (~2500 ppm) and an unusual enrichment in Ge (up to 0.8 wt%) and V (2.8 wt%) in weathered zones of framboïdal pyrite. Sulphur isotopic study of pyrite and organic sulphur provides evidence of bacterial reduction of dominantly seawater sulphates. However taking account the geological context of the three basins, the introduction of volcanic fluids in the basins of Pchelarovo and Vulce Pole during their forma-tion cannot be excluded

Recent advances in the application of stable isotope ratio analysis in forensic chemistry

This review paper updates the previous literature in relation to the continued and developing use of stable isotope ratio analysis in samples which are relevant to forensic science. Recent advances in the analysis of drug samples, explosive materials, and samples derived from human and animal samples are discussed. The paper also aims to put the use of isotope ratio mass spectrometry into a forensic context and discuss its evidential potential

Retrospective Isotopic Analysis of Summertime Urban Atmospheric Sulfate in South Asia Using Improved Source Constraints

The emissions of sulfur dioxide (SO2), a harmful atmospheric pollutant, are on the rise in South Asia. Sulfate, formed from the oxidation of SO2, often comprises 10%–67% of aerosol mass and has a profound impact on climate, air quality/human health, and the environment. The potential drivers of sulfate-linked urban air pollution in South Asian megacitiesfacing a choking air pollution crisisremain poorly understood due to a lack of systematic observations. Here, we conducted stable S-isotope (δ34S) fingerprinting of sulfate aerosols in summertime megacity Delhi in South Asia to evaluate the potential drivers. With newly developed region-specific isotopic endmembers in this study, a statistical source apportionment of urban atmospheric sulfate was feasible. Results show that coal combustion (80 ± 12%) and oil combustion (14 ± 11%), followed by road dust (4 ± 3%) and biomass burning (2 ± 2%), were major contributors to atmospheric sulfate in summertime Delhi. Retrospective analysis showed a marked isotopic shift in stable sulfate isotopic composition in summertime megacity Delhi wherein the average δ34S value was 4 ± 1‰ in 2015 and 2 ± 1‰ in 2021, respectively. This was evidently linked to changes in the dominant fuel type as sulfate sourced from coal combustion (oil combustion) significantly increased ∼ 20% (decreased ∼ 20%) during this period. With no clear increase in the number of thermal power plants in and around Delhi, we speculate that the substantial increase in coal-derived sulfate could plausibly be linked to a rise in the informal industries such as brick production and food and agricultural product processing operations, whose SO2 emissions remain challenging to estimate. While further observations from the region are warranted, the findings here suggest that the continued dependence on coal in developing nations of South Asia could be one of the reasons for rising SO2 levels

Radiocarbon (14C) analysis of carbonaceous aerosols: revisiting the existing analytical techniques for isolation of black carbon

Air pollution, a complex cocktail of different components, exerts an influence on climate/human; health both locally and away from source regions. The issue of air pollution is often closely linked; to carbonaceous aerosols, the assessment of climate/air quality/health impact of which remains associated with large uncertainties. Black carbon (BC)—a product of incomplete combustion—is a potent climate warming agent and one of the central components to this issue. An accurate; knowledge of BC emitting sources is necessary for devising appropriate mitigation strategies and; policies to reduce the associated climate/environmental burden. The radiocarbon isotope (14C or carbon-14) fingerprinting allows for an unambiguous and quantitative constraining of the BC sources and is therefore a well-popularized method. Here, we review the existing analytical techniques for the isolation of BC from a filter matrix for conducting 14C-based investigations. This work summarizes the protocols in use, provides an overarching perspective on the state-of- the-art and recommendations for certain aspects of future method development

Mineralogical and isotopic record of biotic and abiotic diagenesis of the Callovian-Oxfordian clayey formation of Bure (France)

International audienceThe Callovian-Oxfordian (COx) clayey unit is being studied in the Eastern part of the Paris Basin at depths between 400 and 500 m depth to assess of its suitability for nuclear waste disposal. The present study combines new mineralogical and isotopic data to describe the sedimentary history of the COx unit. Petrologic study provided evidence of the following diagenetic mineral sequence: (1) framboidal pyrite and micritic calcite, (2) iron-rich euhedral carbonates (ankerite, sideroplesite) and glauconite (3) limpid calcite and dolomite and celestite infilling residual porosity in bioclasts and cracks, (4) chalcedony, (5) quartz/calcite. Pyrite in bioturbations shows a wide range of δ34S (−38‰ to +34.5‰), providing evidence of bacterial sulphate reduction processes in changing sedimentation conditions. The most negative values (−38‰ to −22‰), measured in the lower part of the COx unit indicate precipitation of pyrite in a marine environment with a continuous sulphate supply. The most positive pyrite δ34S values (−14‰ up to +34.5‰) in the upper part of the COx unit indicate pyrite precipitation in a closed system. Celestite δ34S values reflect the last evolutionary stage of the system when bacterial activity ended; however its deposition cannot be possible without sulphate supply due to carbonate bioclast dissolution. The 87Sr/86Sr ratio of celestite (0.706872-0.707040) is consistent with deposition from Jurassic marine-derived waters. Carbon and oxygen isotopic compositions of bulk calcite and dolomite are consistent with marine carbonates. Siderite, only present in the maximum clay zone, has chemical composition and δ18O consistent with a marine environment. Its δ13C is however lower than those of marine carbonates, suggesting a contribution of 13C-depleted carbon from degradation of organic matter. δ18O values of diagenetic chalcedony range between +27‰ and +31‰, suggesting precipitation from marine-derived pore waters. Late calcite crosscutting a vein filled with chalcedony and celestite, and late euhedral quartz in a limestone from the top of the formation have lower δ18O values (not, vert, similar+19‰), suggesting that they precipitated from meteoric fluids, isotopically close to present-day pore waters of the formation. Finally, the study illustrates the transition from very active, biotic diagenesis to abiotic diagenesis. This transition appears to be driven by compaction of the sediment, which inhibited movement of bacterial cells by reduction of porosity and pore sizes, rather than a lack of inorganic carbon or sulphates

Oxygen and nitrogen isotopic fractionations during human respiration

International audienceBoth oxygen and nitrogen isotope compositions (δ 18 O and δ 15 N) of exhaled air from 10 individuals were measured. Results show linear relations between isotope variation and the fraction of O 2 used during the respiration process. The isotopic influence of physiological parameters such as smoking habits, age, haemoglobin count, oxygen fixation rate or physical exercise was assessed. Among them, only smoking habits do not have any effect on δ 18 O. δ 15 N differences between inhaled and exhaled air may indicate an active (but minor) role for nitrogen during the human respiration process. Nevertheless, nitrogen fractionation is homogenous among all the individuals, which is coherent with the fact that nitrogen metabolism is controlled by the intestinal bacterial activity.Les compositions isotopiques en oxygène et azote (O et N) de l'air expiré par 10 sujets ont été mesurées. Les résultats montrent des relations linéaires entre les fractionnements isotopiques et la fraction d'oxygène utilisée lors de la respiration. L'influence isotopique de paramètres physiologiques tels que le tabagisme, le taux d'hémoglobine, le taux de fixation de l'oxygène ou l'exercice physique est analysée. Seul le tabagisme semble n'avoir aucun effet sur le O. Les différences de N entre l'air inspiré et expiré pourraient indiquer un rôle actif (mineur) de l'azote durant la respiration. Néanmoins, le fractionnement en azote est homogène pour l'ensemble des sujets, en accord avec le fait que son métabolisme est lié à l'activité bactérienne intestinale

Oxygen Isotope Analysis of Human Bone Phosphate Evidences Weaning Age in Archaeological Populations

Acknowledgements With special thanks to Jean-Jacques Hublin and the MPI-EVA; to Annabell Reiner (MPI-EVA) and Bernd Steinhilber (Universitat Tubingen) for technical support;and to the Deutscher Akademischer Austausch Dienst for financial support to KB during this project (ref: A0970923). This research was funded by the Max Planck Society. TT was financed by the DFG Emmy Noether Program and acknowledges funding by the grant TU 148/2-1 for the Emmy Noether Group Bone Geochemistry. Thanks also tothe University of Aberdeen for support during the preparation of this manuscript.Peer reviewedPostprin