Search Results (33)

This investigation focuses on anthropogenic impacts on metallic element distribution within coal mining ecosystems, particularly addressing soil contamination risks in the Linhuan region. Researchers conducted comprehensive sampling and analysis of surface soil contaminants, specifically quantifying mercury, copper, zinc, iron, aluminum, and lead concentrations. Through integrated application of receptor modeling (PMF) and mercury isotopic fingerprinting methodology, this study established a quantitative assessment framework for pollution source apportionment. The multi-technique approach enables precise identification of contamination pathways and proportional contributions from different anthropogenic activities in the mining environment. Coupled with a human health risk assessment model, the health risks associated with specific sources were evaluated. The results indicate that the concentrations of Hg, Cu, Zn, Fe, Al, and Pb in the soil of the study area are 9.49, 2.80, 4.01, 11.79, 6.32, and 1.03 times the soil background values, respectively, suggesting a certain degree of enrichment of these six heavy metals in the soil. The PMF source contribution results show that the soil heavy metals in the study area have three sources: natural soil formation, a mixture of coal combustion and traffic activities, and coal mining activities, with contribution rates of 31.23%, 31.59%, and 37.18%, respectively. The health risk assessment results for specific sources indicate that the non-carcinogenic risks of soil heavy metals in the local area require sufficient attention. Hg is the main cause of non-carcinogenic health risks for both groups, making it a priority element for controlling soil heavy metal health risks. Coal mining activities are the main source (52.4%) of non-carcinogenic risks, making them a priority control source for soil heavy metal health risks in the study area. These findings provide a theoretical basis for enhancing the refined management of heavy metal pollution and the prevention of health risks in soils of coal mining areas. Full article

We investigated the ontogenetic growth changes in total mercury (THg) concentrations, δ¹³C, δ¹⁵N, and δ¹⁸O values, and body length (BL) of dalli-type Dall’s porpoises. THg concentrations in the liver of mature porpoises stranded in Hokkaido, Japan, were markedly higher than those in the muscle. The THg concentrations in the livers of males and females increased sharply when their BLs exceeded approximately 1.9 m and 1.8 m, respectively, the BLs at which they might attain maturity. The asymptotes of the THg increases were close to their maximum BLs of 2.2 m and 2.0 m for males and females, respectively. The δ¹⁵N levels in muscles were higher in the calves than in the weaned porpoises, probably due to the consumption of ¹⁵N-enriched milk, whereas the δ¹³C values in the calves were variable and similar to those in the weaned porpoises. The δ¹⁸O values of male and female muscles increased with increasing BL. Positive correlations were found between the THg concentrations and either the δ¹³C values or the δ¹⁸O values in the weaned animals, but not with the δ¹⁵N values. These results imply a feeding shift towards deeper pelagic areas with growth, as the δ¹³C and δ¹⁸O values and the THg concentrations tend to be higher in these areas. Full article

Trees mediate critical biogeochemical cycles involving nutrients, pollutants, water, and energy at the interface between terrestrial biosphere and atmosphere. Forest ecosystems significantly influence the global cycling of mercury (Hg), serving as important sinks and potential sources of re-emission through various biotic and abiotic processes. Anthropogenic Hg emissions, predominantly from industrial activities, mining, and fossil fuel combustion, have substantially altered the natural Hg cycle, intensifying ecotoxicological concerns and establishing forests as primary routes for atmospheric Hg deposition into terrestrial reservoirs. This perturbation profoundly affects global atmospheric Hg concentrations, residence times, and spatial distribution patterns. While early investigations focused on forest stands near heavily polluted areas, contemporary research has expanded to diverse ecosystems, revealing that trees provide tissues that function as temporal archives for atmospheric-terrestrial Hg exchange. Leaves capture high-resolution records of contemporary Hg dynamics at sub-annual timescales, whereas annual growth rings preserve multi-decadal chronologies of historical atmospheric exposure. Incorporating this dual temporal perspective is crucial for analysing Hg deposition trends and assessing the efficacy of environmental policies designed to control and mitigate Hg pollution. This review critically evaluates recent developments concerning the ecophysiological determinants of Hg accumulation in trees, highlighting how combined foliar and dendrochemical analytical methods strengthen our mechanistic understanding of vegetation-atmosphere Hg exchange. To enhance biomonitoring approaches, we emphasised the need for methodological standardisation, deeper integration of ecophysiological variables, and consideration of climate change implications as priority research areas. Furthermore, integrating Hg measurements with functional markers (δ¹³C and δ¹⁸O) and Hg isotope analyses strengthens the capacity to differentiate between physiological and environmental influences on Hg accumulation, thereby refining the mechanistic framework underlying effective tree-based Hg biomonitoring. Full article

The tight sandstone reservoirs within the Oligocene Huagang Formation represent one of the most promising exploration targets for future hydrocarbon development in the Xihu Depression of the East China Sea Basin. The reservoir has complex sedimentary and diagenetic processes. In this paper, a variety of methods, such as microscopic image observation, particle size analysis, X-ray diffraction measurement (XRD), heavy minerals, carbon and oxygen isotopes of cement, the homogenization temperature of fluid inclusions, zircon (U-Th)/He isotopes, and high-pressure mercury intrusion (HPMI), are used to analyze the thermal evolution history, diagenetic evolution process, and the causes of differences in diagenetic processes and high-quality reservoirs. This study shows that the provenance of the southern region is derived from western metamorphic rock, while that of the northern region is dominated by northern metamorphic rock, including some eastern volcanic rock. The northern region exhibits a stronger compaction and lower porosity, primarily due to a greater proportion of volcanic rock provenance. Additionally, coarse-grained lithofacies exhibit a higher quartz content and lower proportions of clay minerals and lithic fragment compared to fine-grained lithofacies, consequently demonstrating greater resistance to compaction. The Huagang Formation reservoir has three stages of carbonate cementation, two stages of quartz overgrowth, and two stages of fluid charging. The two stages of fluid charging correspond to two stages of organic acid dissolution. In the northern region, the geothermal gradient is high, and the burial depth is large, so the diagenetic event occurred earlier and is now in the mesodiagenesis B stage, while in the southern region, the geothermal gradient is low, and the burial depth is small and is now in the mesodiagenesis A stage. The southern distributary channel sands and northern high-energy braided channel sands constitute high-quality reservoirs, characterized by a coarse grain size, large pore throats, and minimal cement content. Full article

Heavy metal pollution in agricultural soil has been tightly associated with anthropogenic emissions. Although there are many studies that focus on a regional scale, the source identification of heavy metal contamination on a field scale around industrial areas remains unclear. The average concentrations in topsoils of Hg, Cd, As, Pb, Cr, Ni, Zn, and Cu were 2.07, 0.13, 8.56, 42.3, 81.1, 37.3, 105, and 43.8 mg kg⁻¹, respectively. The enrichment of Hg was particularly presented on topsoils, with the highest single pollution index (Pi) (9.00) and ecological risk index (Eri) (922) values. An integrated methodology was employed in source identification of heavy metals contamination, especially for Hg, including Pearson’s and PCA analysis, soil profile morphology, mathematical modeling, and Hg isotope analysis. Results revealed that the concentrations of Hg decreased as a function of depth, suggesting Hg contamination was an anthropogenic source and can be supported by Hg isotope analysis. The negative Δ¹⁹⁹Hg values of the residual Hg (F4-Hg) and soil profile in 80–100 cm deviate from those of the soil profiles in 0–80 cm, indicating exogenous input of Hg occurred in the study area. According to the UNMIX model, the contribution of coal combustion, agricultural activities, parent material, and industrial/traffic emissions to Hg accumulation in soils were 66.2%, 16.9%, 9.81%, and 7.0%, respectively. However, the contribution rates calculated with the PMF model of mixed industrial source, traffic emissions, and parent material were 71.4%, 27.8%, and 0.8%, respectively. This study can accurately quantify and identify the factors contributing to heavy metal contamination in agricultural soil on a field scale. Full article

Nuclear fusion is a phenomenon that is well known within the nuclear physics community as a viable option for alternative energy as many natural gases and fossil fuels are phased out of commercial use. Deuterium and tritium fusion reactions are currently the leading candidates for nuclear fusion, with a major limiting factor being a means to produce tritium on an industrial scale. Lithium-6 is a well-known isotope that can produce tritium and helium following a fission reaction with a neutron. Unfortunately, the lithium-6 enrichment methods are limited to the COLEX process, which leaves behind an alarming amount of mercury waste as a potential environmental contaminant. Deep eutectic solvents are believed to be a potential alternative to lithium isotope separations due to the ease of generation, in addition to the minimum environmental waste generated when these solvents are employed. Previous studies have suggested that deep eutectic solvents are capable of separating lithium isotopes by utilizing a 2-thenoyltrifluoroacetone and trioctylphosphine oxide system that can biphasically react with a buffered solution containing lithium chloride. This system displays a separation factor of 1.068, which when compared to the 1.054 separation within the COLEX process, makes it a potential candidate for lithium-6/7 separation. Within this study, we investigate this system in comparison to two newly synthesized deep eutectic solvents and find that within these acetylacetone-based systems, little isotopic separation is observed. We investigate these systems both experimentally and computationally, showing the different lithium cation affinities, in addition to proposing how the electron-donating or -withdrawing nature can influence these systems. Full article

The aim of this study was to explore the connection between growth and feeding ecology and mercury (Hg) levels in Japanese anchovy (Engraulis japonicus). We measured the amounts of Hg and stable carbon and nitrogen isotopes in the muscle of 143 Japanese anchovy specimens obtained from the open seas of the Northwest Pacific Ocean (39°2′ N~42°30′ N, 154°02′ E~161°29′ E) between June and July 2021. The results showed that there were significant differences (p < 0.05) in the δ¹³C and δ¹⁵N values of Japanese anchovies across all body length groups. As individuals grew, δ¹³C tended to decrease first and then increase, and δ¹⁵N tended to gradually increase. The standard ellipse corrected area showed an increasing and subsequently decreasing pattern with growth. It reached its greatest value (0.80) in the 111–120 mm group. Compared to the body length group of 91–120 mm, the niche overlap decreased for the 121–140 mm group in Japanese anchovy. Hg levels increased gradually with body length. Linear regression models revealed a positive correlation between Hg levels and δ¹³C in fish. Hg levels increased gradually, while δ¹⁵N remained relatively constant in the 7–9‰ range. In our study, a distinct shift in diet was observed for Japanese anchovy with increasing body length, and the differences in diet among life stages could be responsible for the changes in Hg levels. Full article

The changes in the stable isotope ratios of carbon (δ¹³C), nitrogen (δ¹⁵N), oxygen (δ¹⁸O), and mercury (Hg) concentrations in muscle and liver tissues during and after lactation were studied in killer whales stranded along the coast of Hokkaido, in the northern area of Japan (n = 16). Calf muscles displayed δ¹³C- and δ¹⁵N-enriched peaks and a δ¹⁸O-depleted peak during lactation. The δ¹³C- and δ¹⁵N-enriched peaks appear to reflect the extensive nursing of ¹³C- and ¹⁵N-enriched milk and the onset of weaning, whereas the δ¹⁸O-depleted peak may be attributable to the extensive nursing of ¹⁸O-depleted milk and the onset of weaning. The δ¹³C and δ¹⁵N values tended to gradually increase after the weaning, whereas the δ¹⁸O values tended to decrease. The δ¹³C and δ¹⁵N levels in calves were similar between liver and muscle samples, whereas those in mature animals were higher in liver than in muscle samples. The isotopic turnover rates of C and N may be similar between the liver and muscle tissues in calves, which are rapidly growing animals. The Hg concentrations in muscle tissues were slightly higher in small calves than in large calves, probably due to the Hg transfer across placenta. The Hg concentrations in liver and muscle samples increased with increasing body length, and those in two liver samples from mature animals exceeded the high-risk threshold for marine mammal health effects (82 μg/wet g). Full article

To facilitate the efficient exploration and development of coalbed methane of the Longtan Formation in the Guxu coal mining area, Sichuan, it is essential to evaluate the reservoir characteristics of the main production layers. In this study, scanning electron microscopy, low-temperature liquid nitrogen adsorption experiments, high-pressure mercury pressure experiments, and isothermal adsorption experiments were conducted to investigate the reservoir characteristics of favorable coalbed methane reservoirs. The results indicate that the main coal seams in the Longtan Formation are medium-to-high ash content anthracite with a well-developed pore–fracture system. The pore size distribution exhibits both unimodal and bimodal types, while the pore morphology includes impermeable pores closed at one end, open permeable pores, and ink bottle-shaped pores. It shows that the middle part of Longtan Formation acts as an enrichment zone for coalbed methane, which is characterized by a stronger adsorption capacity, high Langmuir volume, high gas content, and high gas saturation distribution. The pH value, mineralization degree, and hydrogen–oxygen isotope of the produced water in the main coal seams indicate that the enrichment zone is typically located in a stagnant flow zone with a reducing environment and favorable storage conditions. Full article

Although extensive research has been carried out on the occurrence of mercury (Hg) in biota, bioaccumulation and tissue distribution of Hg in songbirds have not been well characterized. In the present study, Hg was investigated in insects and barn swallows (Hirundo rustica) to explore the bioaccumulation characteristics of Hg. Hg in swallow feathers and tissues including muscle, liver, and bone was investigated to determine the tissue distribution of Hg. The concentrations of Hg were 1.39 ± 1.01 μg/g, 0.33 ± 0.09 μg/g, 0.47 ± 0.10 μg/g, and 0.23 ± 0.09 μg/g in feather, muscle, liver, and bone samples, respectively. The trophic magnification factor of Hg in swallows and insects was higher than 1. However, the Hg concentrations in swallow feathers were not significantly correlated with stable isotope values of carbon or nitrogen, which implies the complex food sources and exposure processes of Hg for swallows. Feathers had significantly higher concentrations of Hg than liver, muscle, and bone samples (p < 0.01 for all comparisons). Feather, muscle, bone, and other organs had fractions of 64.4 ± 11.9%, 6.07 ± 2.06%, 20.0 ± 8.19%, and 9.56 ± 2.96% in total body burden of Hg in swallows. Hg in feathers contributed more than half of Hg in the whole body for most swallow individuals. Swallows may efficiently eliminate Hg by molting, and the excretion flux of Hg and other contaminants via molting deserves more investigation. Full article

The Zhen’an-Xunyang Basin is a late Paleozoic rifted basin with a series of Au-Hg-Sb deposits that have been found, mostly along the Nanyangshan fault. Recently discovered large- and medium-sized gold deposits such as the Xiaohe and Wangzhuang deposits exhibit typical characteristics of Carlin-type gold deposits. Therefore, it is imperative to select a typical deposit for an in-depth study of its metallogenic mechanism to support future prospecting efforts targeting the Carlin-type gold deposits within the area. Based on detailed field investigation and microphotographic observation, four ore-forming stages are identified: I, low-sulfide quartz stage, characterized by euhedral, subhedral pyrite, and fine veins of quartz injected parallel to the strata; II, arsenopyrite–arsenian pyrite–quartz stage, the main mineralization stage characterized by strongly silicified zones of reticulated quartz, disseminated arsenopyrite, fine-grained pyrite; III, low-sulfide quartz stage, characterized by large quartz veins cutting through the ore body or fine veins of quartz; Ⅳ, carbonate–quartz stage, characterized by the appearance of a large number of calcite veins. In situ analysis of trace elements and S isotopes of typical metal sulfides was carried out. The results show significant variations in the trace element compositions of metal sulfides in different stages, among which the main mineralization stage differs notably from those of the Au- and As-low surrounding strata. In situ S isotope analysis reveals δ³⁴S values ranging from 15.78‰ to 28.71‰ for stage I metal sulfides, 5.52‰ to 11.22‰ for stage II, and 0.3‰ to 5.25‰ for stage III, respectively, revealing a gradual decrease in S isotopic values from the pre-mineralization stage to post-mineralization stage, similar to those observed in the Xiaohe gold deposit. These features indicate a distinct injection of relatively low ³⁴S hydrothermal fluids during the mineralization process. The element anomalies of the 1:50,000 stream sediment in the region revealed ore-forming element zonation changing in W→Au (W)→Hg, Sb (Au) anomalies from west to east, manifested by the discovery of tungsten, gold, and mercury–antimony deposits in the area. Moreover, conspicuous Cr-Ni-Ti-Co-Mo anomalies were observed on the western side of the Wangzhuang and Xiaohe gold deposits, indicating a potential concealed pluton related to these deposits. These lines of evidence point to a magmatic–hydrothermal origin for the Carlin-type gold deposits in this area. Furthermore, hydrothermal tungsten deposits, Carlin-type gold deposits, and low-temperature hydrothermal mercury–antimony deposits in this region are probably controlled by the same magma–hydrothermal system. Full article

Microfluidic paper-based analytical devices (μPADs) have been developed for use in a variety of diagnosis and analysis fields. However, conventional μPADs with an open-channel system have limitations for application as analytical platforms mainly because of the evaporation and contamination of the sample solution. This study demonstrates the design and fabrication of an enclosed three-dimensional(3D)-μPAD and its application as a primary early analysis platform for ionic contaminants. To generate the hydrophobic PDMS barrier, double-sided patterning is carried out using a PDMS blade-coated stamp mold that is fabricated using 3D printing. The selective PDMS patterning can be achieved with controlled PDMS permeation of the cellulose substrate using 3D-designed stamp molds. We find the optimal conditions enabling the formation of enclosed channels, including round shape pattern and inter-pattern distance of 10 mm of stamp design, contact time of 0.5 min, and spacer height of 300 µm of double-sided patterning procedure. As a proof of concept, this enclosed 3D-μPAD is used for the simultaneous colorimetric detection of heavy metal ions in a concentration range of 0.1–2000 ppm, including nickel (Ni²⁺), copper (Cu²⁺), mercury (Hg²⁺), and radioactive isotope cesium-137 ions (Cs⁺). We confirm that qualitative analysis and image-based quantitative analysis with high reliability are possible through rapid color changes within 3 min. The limits of detection (LOD) for 0.55 ppm of Ni²⁺, 5.05 ppm of Cu²⁺, 0.188 ppm of Hg²⁺, and 0.016 ppm of Cs+ are observed, respectively. In addition, we confirm that the analysis is highly reliable in a wide range of ion concentrations with CV values below 3% for Ni²⁺ (0.56%), Cu²⁺ (0.45%), Hg²⁺ (1.35%), and Cs⁺ (2.18%). This method could be a promising technique to develop a 3D-μPAD with various applications as a primary early analysis device in the environmental and biological industries. Full article

To determine the range of the isotopic composition of mercury (Hg) from the Idrija mine, samples from the mine itself and from the Mercury Heritage Management Centre geological collection were analyzed. Samples from various geological periods, genesis types, ore types, formations, and excavation fields and levels were analyzed. Both Hg concentration and isotopic composition were measured. The δ²⁰²Hg ranged from −1.35‰ to 0.46‰, and the Δ¹⁹⁹Hg ranged from −0.18‰ to 0.16‰. A relatively homogenous ore fingerprint was obtained from one of the excavation fields; otherwise, the isotopic fingerprint of the Idrija mine seems to be heterogenous. This study presents the first statistically robust constraints on the isotopic composition of Hg from the Idrija mine, which may help in further studies of the isotopic composition of similar ore bodies or the potential tracing of Hg from the mine to the environment in the vicinity or downstream of the mine. Full article

Although mercury (Hg) mining activities in the Wanshan area have ceased, mine wastes remain the primary source of Hg pollution in the local environment. To prevent and control Hg pollution, it is crucial to estimate the contribution of Hg contamination from mine wastes. This study aimed to investigate Hg pollution in the mine wastes, river water, air, and paddy fields around the Yanwuping Mine and to quantify the pollution sources using the Hg isotopes approach. The Hg contamination at the study site was still severe, and the total Hg concentrations in the mine wastes ranged from 1.60 to 358 mg/kg. The binary mixing model showed that, concerning the relative contributions of the mine wastes to the river water, dissolved Hg and particulate Hg were 48.6% and 90.5%, respectively. The mine wastes directly contributed 89.3% to the river water Hg contamination, which was the main Hg pollution source in the surface water. The ternary mixing model showed that the contribution was highest from the river water to paddy soil and that the mean contribution was 46.3%. In addition to mine wastes, paddy soil is also impacted by domestic sources, with a boundary of 5.5 km to the river source. This study demonstrated that Hg isotopes can be used as an effective tool for tracing environmental Hg contamination in typical Hg-polluted areas. Full article

The production of medical isotopes in Chalk River Laboratories facilities (Chalk River, ON, Canada) has resulted in a large quantity of cemented radioactive waste (CRW) containing valuable elements such as uranium. From the perspective of recovering and ultimately recycling valuable elements from CRW, the solubilization of key constituents such as uranium, mercury, and cesium has been previously investigated using H₂SO₄/KI. However, to achieve recycling of these elements, separation must be performed as they are co-solubilized. In this study, the extraction of uranium and mercury by chelating resin Lewatit TP260 from surrogate cemented radioactive waste (SCRW) leaching solution in sulfuric media and in the presence of iodide was investigated. Extraction of U and Hg was assessed as a function of the concentration of KI (0.12 M to 0.24 M) used during the SCRW dissolution process. Continuous experiments showed that the Lewatit TP260 functional group, aminomethylphosphonic acid, had a high affinity for U. Mercury was also extracted onto the Lewatit TP260. However, the presence of iodide in the SCRW leaching solution increased the competition between the adsorbed mercury of the stationary phase and the iodide–mercury complexes of the mobile phase. Additionally, the reusability of the resin was tested through extraction and desorption cycles. Due to the presence of trivalent cation, the capacity of Lewatit TP260 for U and Hg decreases with the number of cycles. Full article