Isotopes in Environmental and Health Studies最新文献

The region around the tip of the Antarctic Peninsula is warming fast, a situation that will lead to widespread changes in local hydrological cycles. King George Island (KGI) hosts a complex network of lakes and rivers, fed by glaciers, snow and rain, and underlain by thick permafrost. We present here the first study of the stable isotope composition of the surface waters in the ice-free southern peninsulas of KGI. Permafrost samples had the highest δ¹⁸O and δ²H values (-6.7 and -50 ‰, respectively), and river waters the lowest (-9.1 and -70 ‰, respectively), with groundwater (-8.2 and -62.7 ‰, respectively), lakes (-8.6 and -66.8 ‰, respectively) and (summer) meltwater (-9 and -69.5 ‰, respectively) having intermediary values. Our results suggest that a clear separation of the various water bodies (permafrost, snow, meltwater, lakes) based on the δ¹⁸O_water and δ²H_water is possible. Further, water in lakes on a W-E transect (i.e. with increased distance from the Bellingshausen Sea) have a general tendency towards lower δ¹⁸O (and δ²H) values. The results allow for the establishment of a baseline against which ongoing and future changes of the hydrological cycle could be analysed, and past climate changes be reconstructed.

Krypton-81 was applied to investigate the age of groundwater in the aquifer system in the Bangkok metropolitan and vicinity areas. Stable (²H, ¹⁸O and ¹³C) and radioactive (³H, ⁸⁵Kr and ¹⁴C) isotopes and noble gases were applied in parallel. Low levels of ¹⁴C and significant radiogenic ⁴He confirm that groundwater in the deep aquifers is older than 30 ka. ⁸¹Kr analysis identified groundwater with ages ranging from 17 to 300 ka. At some sites, large age discrepancies between ⁸¹Kr and ¹⁴C indicated that inter-aquifer mixing is likely occurring. The interpretation of the noble gases suggests that groundwaters in the deeper aquifers, with apparent ages of 300 to 10 ka, have recharged in slightly colder and wetter climates than those found in the upper aquifers with apparent ages < 10 ka. Degradation of water quality from seawater intrusion was identified in the upper four aquifers. This was also evidenced by higher δ¹⁸O and δ²H values, typical of seawater. The four deeper aquifers contain high quality water characterised by less enriched ¹⁸O and ²H. This work presents new findings of very old groundwater in the Bangkok aquifer system.

In the Himalayas, the lives and livelihoods of millions of people are sustained by water resources primarily depending on the moisture brought by Western Disturbances and Indian Summer Monsoon. In the present study, a network of 12 precipitation stations was established across the Kashmir Valley to understand the spatial and meteorological factors controlling precipitation isotopes. Temperature and relative humidity are dominant meteorological factors, whereas altitude, proximity to forest canopy, land use/land cover, windward and leeward sides of the mountains are the main physical factors influencing precipitation isotopes. The study suggests that the Mediterranean Sea and nearby water bodies along with continental recycling are the dominant sources of moisture from October to May, while the Arabian Sea, Bay of Bengal and continental recycling are the main sources of moisture from June to September. However, some precipitation events from October to May collect moisture from the Arabian Sea and some precipitation events from June to September collect moisture from the Mediterranean Sea. The occasional passage of Western Disturbances in summer merging with the Indian Summer Monsoon yields heavy to very heavy precipitation. The study provides a better understanding of complex spatial and meteorological phenomena controlling precipitation isotopes across the Western Himalayas.

This paper presents a detailed review of the use of ⁸⁷Sr/⁸⁶Sr isotope systematics for wine provenance studies. The method is based on the principle that the Sr isotope ratio in wine reflects that of the labile fraction of the vineyard soil from which the wine is produced. The review encompasses ⁸⁷Sr/⁸⁶Sr data from wine samples published between 1993 and 2021 from terroirs in 22 different countries. The analytical procedures and techniques adopted by the different authors and the range of isotope ratios obtained in the different studies are discussed and evaluated. This study provides a bibliometric analysis of the ⁸⁷Sr/⁸⁶Sr isotope approach for wine authentication at different scales. Although limitations are evident when implemented at large (global) scales, we demonstrate that the ⁸⁷Sr/⁸⁶Sr isotope tracing technique remains a powerful and reliable tool for determining the geographical origin of wine when combined with detailed knowledge of the geological and soil characteristics of the substrata. For example, this combination of data allows the wines grown in the volcanic soils of Central and Southern Italy to be unambiguously fingerprinted. We present a detailed protocol for the application of the Sr isotope technique to wine authentication.

This study aimed to evaluate natural radioactivity levels and hazards of radionuclides ²³²Th, ²²⁶Ra and ⁴⁰K in soil samples taken from 15 locations in the Lega Dembi gold mining, Oromia, Ethiopia, using gamma-ray spectroscopy coupled with an HPGe detector. It was observed that the respective mean specific activities for ²²⁶Ra, ²³²Th and ⁴⁰K determined in the mining site were 23.87 ± 0.7, 52.5 ± 1.8 and 391.62 ± 11.35 Bq/kg, and 8.89 ± 0.4, 13.83 ± 0.6 and 423.68 ± 9.5 Bq/kg in the living areas. The specific activity of ²³²Th was above the permissive limit in the mining site, while for ²²⁶Ra and ⁴⁰K were within the limit. The specific activity of ⁴⁰K in the living area was observed to be above the permissive limit. The calculated value of radiation hazards parameters; radium equivalent activity (Ra_eq), internal and external hazards indices (H_in) and (H_ex), the mean annual effective dose (AED), and gamma representative indices (I_γ) were within permissively limit. The mean absorbed dose rate in the mining site was above the recommended safety limit. The total annual gonadal dose equivalent value was found to be 494.8 ± 8.7 µSv/a in the mining site. This value was also above the permissively.

There is an increasing global demand for regional and organic produce. However, the growth of these markets depends on consumers' trust. Thus, novel methods must be developed to aid the verification of the origin of produce. We built on our previous study to identify the geographical origin and production method of animal-derived food products. Thirty-samples of eggs, 99 of milk, 34 of beef, and 62 of pork were collected from different regions in central Germany and analysed for their stable isotopic composition. The analysis followed a single-variate authentification approach using five isotope signatures, δ¹⁸O, δ²H, δ¹³C, δ¹⁵N, and δ³⁴S. The best-performing indicators for verification of the geographical origin were δ¹⁵N and δ³⁴S for beef; δ¹⁸O, δ²H, and δ¹³C for milk, and δ²H and δ¹³C for pork. These tracers indicated statistically significant differences among regions with the exception of pork; the results recorded for eggs were inconclusive. It was possible to distinguish between production methods by means of δ¹⁵N and δ³⁴S (beef); all five tracers (eggs), and δ¹³C, δ¹⁵N, and δ³⁴S (milk). This study demonstrated how the analysis of stable isotopes can be employed to determine the geographic region of origin and production method of animal-derived products in Germany.

After the atmosphere, the ocean is the most well-mixed and homogeneous global geochemical reservoir. Both physical and biological processes generate elemental and isotope variations in seawater. Contrasting geochemical behaviors cause elements to be susceptible to different fractionation mechanisms, with their isotopes providing unique insights into the composition and evolution of the ocean over the course of geological history. Supplementing the traditional stable isotopes (H, C, O, N, S) that provide information about ocean processes and past environmental conditions, radiogenic isotope (Sr, Nd, Os, Pb, U) systems can be used as time markers, indicators of terrestrial weathering, and ocean water mass mixing. Recent instrumentation advances have made possible the measurement of natural stable isotope variations produced by both mass-dependent and mass-independent fractionation for an ever-increasing number of metal elements (e.g. Li, B, Mg, Si, Ca, V, Cr, Fe, Ni, Cu, Zn, Se, Mo, Cd, Tl, U). The major emphasis in this review is on the isotopic composition of the light elements based on a comparatively large literature. Unlike O, H and S, the stable isotopes of C, N and Si do not have a constant isotopic composition in the modern ocean. The major cations Ca, Mg, and Sr fixed in carbonate shells provide the best proxies for reconstruction of the composition of the ocean in the past. Exhibiting large isotope enrichments in ocean water, B and Li are suitable for the investigation of water/rock interactions and can act as monitors of former oceanic pH. The bioessential elements Zn, Cd, and Ni are indicators of paleoproductivity in the ocean. Characteristic isotope enrichments or depletions of the multivalent elements V, Cr, Fe, Se, Mo, and U record the past redox state of the ocean/atmosphere system. Case studies describe how isotopes have been used to define the seawater composition in the geological past.

Radium-226 detection in sediment samples is generally executed by means of gamma-ray spectrometry. Data evaluation relies (besides the 186.2 keV ²²⁶Ra gamma peak) on the combined analysis of major gamma peaks that are produced by the short-lived radon (²²²Rn) daughters ²¹⁴Pb and ²¹⁴Bi. Precondition for this detection approach is equilibrium decay of all members of the decay chain between ²²⁶Ra and ²¹⁴Bi. In closed systems, this equilibrium is reached after about five half-lives of ²²²Rn (19 days). However, a closed system can only be guaranteed if the capsule which contains the sample prevents diffusive escape of radon. Such radon-tightness cannot be guaranteed for a wide range of plastic materials. Due to its polymer structure, plastic material generally tends to allow radon diffusion and hence radon loss from the sample resulting in a disturbance of the required decay equilibrium. The paper introduces an approach that allows quantifying radon loss from sample capsules by direct radon measurements using mobile radon detection equipment. The experimental findings are supported by theoretical considerations. An examined alternative approach based on the offset of the 186.2 keV data point from an efficiency function that is calculated exclusively from short-lived radon progeny peaks in the gamma-ray spectrum did not prove to be applicable due to a lack of supporting peaks in the low-energy section of the spectrum.