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To draw the balance of anthropogenic 129I input into European soils, the concentrations of 129I and 127I in seven soils from Lower Saxony were analyzed down to a depth of 250 cm. In comparison with pre-nuclear soils and Ukrainian soils, we detected a significant anthropogenic input of 129I. Considering the different time periods for the input of 129I and 127I it was possible to assess the dynamics of sorption processes which dominate migration and accumulation. Anthropogenic 129I was successfully used as a tracer for a clarification of the migration processes of trace elements in soils.

ABSTRACTSince radiocarbon accelerator mass spectrometry (14C AMS) is considered a high-precision technique, reassessment of the measurement uncertainty has been a topic of interest. Scientists from analytical and metrological fields have developed the top-down and bottom-up measurement of uncertainty approaches. The 14C quoted error should approximate the uncertainty of long-term repetitions of the top-down approach in order to be realistic. The novelty of this paper is that the uncertainty of both approaches were approximated to each other. Furthermore, we apportioned the graphitization, instrumentation, and bias components in order to additively expand the quoted error. Our results are comparable to error multipliers and to long-term repeatability studies reported by other laboratories. Our laboratory was established in late 2012 with N2as stripper gas and 7 years later, we changed to helium stripper. Thus, we were able to compare both gases, and demonstrate that helium is a better stripper gas. In absolute F14C units, the ranges of graphitization+bias combined uncertainties were (0.7 to 4.1) × 10–3for N2and (0.7–3.0) × 10–3for He depending on the standard 14C content. The error multiplier for He defined as the expanded uncertainty over quoted error, in average, was 1.7; while without the bias, the multiplier was 1.3.

ABSTRACTWe present the current performance of the in situ radiocarbon (14C) extraction line at the University of Bern with an improved extraction and combustion system. After three major steps of improvement, the extraction of sample CO2gas now takes place inside a platinum crucible, supported by an outer quartz-glass crucible. This setup allows us to operate the line as a closed system for several samples without breaking the vacuum. Measurements of procedural blanks and samples from our reference strewn field, Jiddat al Harasis 073, performed in our system all show a good reproducibility and, for the strewn field samples, consistency with published data. We describe each improvement step in detail, discussing the advantages and disadvantages of all tested setups. By sharing our knowledge, we aim to inform and prevent others from making the same or similar detours in establishing 14C extraction systems for extraterrestrial samples.

ABSTRACTMethane contributes substantially to global warming as the second most important anthropogenic greenhouse gas. Radiocarbon (14C) measurements of atmospheric methane can be used as a source apportionment tool, as they allow distinction between thermogenic and biogenic methane sources. However, these measurements remain scarce due to labor-intensive methods required. A new setup for the preparation of atmospheric methane samples for radiocarbon analysis is presented. The system combines a methane preconcentration line with a preparative gas chromatography technique to isolate pure methane samples for a compound-specific radiocarbon analysis. In order to minimize sample preparation time, we designed a simplified preconcentration line for the extraction of methane from 50 L atmospheric air, which corresponds to 50 µg C as required for a reliable 14C analysis of methane-derived CO2gas measurement with accelerator mass spectrometry (AMS). The system guarantees a quantitative extraction of methane from atmospheric air samples for 14C analysis, with a good repeatability and a low processing blank. The setup was originally designed for the measurement of samples with low methane concentrations, but it can also be adapted to apportion sources from environmental compartments with high methane levels such as freshwaters or wetlands.

Black carbon (BC) particles produced by incomplete combustion of biomass and fossil fuels warm the atmosphere and decrease the reflectivity of snow and ice, hastening their melt. Although the significance of BC in Arctic climate change is widely acknowledged, observations on its deposition and sources are few. We present BC source types in a 300‐year (1700–2005) Svalbard ice core by analysis of particle‐bound organic compounds, radiocarbon, and trace elements. According to the radiocarbon results, 58% of the deposited elemental carbon (EC, thermal‐optical proxy of BC) is of non‐fossil origin throughout the record, while the organic compounds suggest a higher percentage (68%). The contribution of fossil fuels to EC is suggested to have been elevated between 1860 and 1920, particularly based on the organics and trace element data. A second increase in fossil fuel sources seems to have occurred near the end of the record: according to radiocarbon measurements between 1960 and 1990, while the organics and trace element data suggest that the contribution of fossil fuels has increased since the 1970s to the end of the record, along with observed increasing EC deposition. Modeled atmospheric transport between 1948 and 2004 shows that increasing EC deposition observed at the glacier during that period can be associated with increased atmospheric transport from Far East Asia. Further observational BC source data are essential to help target climate change mitigation efforts. The combination of robust radiocarbon with organic compound analyses requiring low sample amounts seems a promising approach for comprehensive Arctic BC source apportionment. Black carbon (BC) is a fine particulate emission component formed in natural and anthropogenic combustion of biomass and fossil fuels. BC effectively warms the atmosphere, and when it is deposited on snow and ice, it hastens their melt. BC strongly amplifies Arctic climate change but information on its deposition variations and sources are still very scarce. We studied sources of BC in a Svalbard (high‐Arctic) ice core covering the years 1700–2005 by analysis of chemical compounds, radiocarbon and trace elements. We found that throughout the ice core, the contribution of biomass combustion to BC was higher (ca. 60%–70%) than that of fossil fuels. The contribution of fossil fuel sources to BC in the ice core was elevated in 1860–1920, and again at the end of the record starting in the 1960s–1970s. Atmospheric transport modeling shows that increasing BC deposition observed at the glacier since the 1970s was associated with airmasses arriving increasingly from Far East Asia. Further observations on Arctic BC sources are essential to inform decision makers on which BC emissions most affect Arctic climate change. Non‐fossil sources have dominated (ca. 60%–70%) elemental carbon (EC) deposition in a Svalbard ice core between 1700 and 2005The contribution of fossil fuels to EC was highest between 1860 and 1920 and toward the end of the record starting in the 1960s or 1970sAtmospheric transport modeling indicates that observed increased EC deposition was associated with potential Asian sources in 1948–2004 Non‐fossil sources have dominated (ca. 60%–70%) elemental carbon (EC) deposition in a Svalbard ice core between 1700 and 2005 The contribution of fossil fuels to EC was highest between 1860 and 1920 and toward the end of the record starting in the 1960s or 1970s Atmospheric transport modeling indicates that observed increased EC deposition was associated with potential Asian sources in 1948–2004

129I concentrations in precipitation at Dübendorf/Zürich, Switzerland, have been determined with monthly resolution for almost three years in the mid 1990s. The results confirm that annual mean 129I concentrations in precipitation in central Europe have remained about constant since the late 1980s. Liquid and gaseous emissions from the nuclear fuel reprocessing plants at Sellafield and La Hague are discussed as the only possible sources of 129I in precipitation in central Europe. Based on an upper limit estimate for iodine transferred from the sea to the atmosphere, the gaseous discharges constitute the potentially bigger 129I reservoir for precipitation. Moreover, the time dependence of the annual gaseous 129I releases from Sellafield and La Hague correlates much better with the 129I concentrations in precipitation in central Europe since the late 1980s than does the time dependence of the liquid emissions from these sites. At monthly resolution, the 129I concentrations in the precipitation samples close to Zürich exhibit a large variability. A meteorological transport analysis was carried out for four selected months with particularly low or high observed 129I concentrations. It was found that meteorological transport alone, based upon assimilated wind fields and observed precipitation values, can not directly account for the large month-to-month variability.

The long-lived radionuclide 129I (T1/2= 15.7 My) occurs in the nature in very low concentrations. Since the middle of our century the environmental levels of 129I have been dramatically changed as a consequence of civil and military use of nuclear fission. Its investigation in environmental materials is of interest for environmental surveillance, retrospective dosimetry and for the use as a natural and man-made fracers of environmental processes. We are comparing two analytical methods which presently are capable of determining 129I in environmental materials, namely radiochemical neutron activation analysis (RNAA) and accelerator mass spectrometry (AMS). Emphasis is laid upon the quality control and detection capabilities for the analysis of 129I in environmental materials. Some applications are discussed.

Cannabinoids were extracted from serum with C18 SPE cartridges and analyzed as their trimethylsilyl (TMS) derivatives. A benchtop gas chromatography-tandem mass spectrometry (GC-MS-MS) system based on an ion trap with external ionization was used. Quantitation was done in relation to trideuterated internal standards in dual MS-MS mode. Confirmation of the identity for the three compounds of interest, Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH), was achieved by registering the daughter spectra in full scan mode. It was possible to identify the three compounds at concentrations down to 0.25 µg/L for THC, 0.5 µg/L for 11-OH-THC, and < 2.5 µg/L for THCCOOH by comparison with reference spectra. The limits of quantitation are better than 2 µg/L for THC, 5 µg/L for 11-OH-THC, and 8 µg/L for THCCOOH. The within-run and day-to-day precision for the three analytes were very similar and ranged from 4.2 to 10.4%.