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The COVID-19 pandemic catalyzes new opportunities for CSR development, and companies in both China and the US, the two largest economies severely impacted by the pandemic, are seeking innovative ways to engage with publics on social media through CSR communication. This study draws on the care ethics theory to examine different manifestations of care values in corporations' CSR messages and their relationships with publics' behavioral and emotional engagement on social media. A quantitative content analysis of Weibo and Twitter posts from Fortune 500 companies in China (n = 30) and the United States (n = 30), respectively, revealed that companies in both countries employ multifaceted care-based CSR messages, but in distinct ways and with varying types and levels of public engagement on social media. We interpreted the differences from institutional, cultural, and relational perspectives. The results of this research add to theorizing CSR communication from a feminist ethical viewpoint and with contextualized interpretations. Our findings also guide post-pandemic CSR communication development, particularly relevant to public relations practitioners in the Chinese and US markets. [ABSTRACT FROM AUTHOR]

The study on the origin of quartz and silica in Xuanwei Formation coal in Northwest Yunnan, China, is helpful to understand the relationship between quartz and silica and the high incidence of lung cancer from the root. To address these questions, the mineralogy and microscopic studies of silica in Xuanwei Formation coal were performed. The following results were obtained: (1) silica in the late Permian Xuanwei Formation coal seams originated from detrital input, early diagenesis, and late diagenesis. (2) A more significant contribution comes from early diagenesis, which contains abundant authigenic quartz and amorphous silica. (3) Quartz and silica from inorganic silicon are more symbiotic with kaolinite and from biogenic silicon with chamosite. (4) Three silica polymorphs in coal samples have been identified: opal-A (amorphous silica), opal-CT/-C (cristobalite/tridymite), and α quartz. (5) Opal-A is ubiquitous, while opal-CT/-C and α quartz are rare. (5) Opal-A is an amorphous and nontoxic ordinary silica. (6) Since the toxicity of amorphous silica and its presence in coal is an emerging topic, it should be continuously monitored. [ABSTRACT FROM AUTHOR]

This work aims to understand the distribution and migration mechanisms of U and Mo between surface sediment and water in acid mine drainage (AMD) regions near a molybdenum mining region. A series of river sediment and water samples near the Jinduicheng mining area, one of the largest deposits of molybdenite ore in Asia, were collected and analyzed. Our results indicate that: (1) The pH value of river water samples increases with distance from upstream to downstream, while the pH has poor correlation with Mo and U; (2) The content of Mo and U in the sediment are significantly higher than the background value, which suggests potential pollution; (3) The content of Mo and U in the water and sediments in the lower reaches of the Wenyu river is significantly linearly related with the distance from the mining area, suggesting that AMD is a potential source; (4) BCR analysis shows that Mo in river sediments mainly existed as the residual, while U mainly existed as the non-residual; (5) The distribution coefficient Kd(Mo) exceeds Kd(U), indicating that Mo is enriched in sediments while U is more prone to porewater. [ABSTRACT FROM AUTHOR]

Metal mineral mining results in releases of large amounts of heavy metals into the environment, and it is necessary to better understand the response of rhizosphere microbial communities to simultaneous stress from multiple heavy metals (HMs), which directly impacts plant growth and human health. In this study, by adding different concentrations of cadmium (Cd) to a soil with high background concentrations of vanadium (V) and chromium (Cr), the growth of maize during the jointing stage was explored under limiting conditions. High-throughput sequencing was used to explore the response and survival strategies of rhizosphere soil microbial communities to complex HM stress. The results showed that complex HMs inhibited the growth of maize at the jointing stage, and the diversity and abundance of maize rhizosphere soil microorganisms were significantly different at different metal enrichment levels. In addition, according to the different stress levels, the maize rhizosphere attracted many tolerant colonizing bacteria, and cooccurrence network analysis showed that these bacteria interacted very closely. The effects of residual heavy metals on beneficial microorganisms (such as Xanthomonas, Sphingomonas, and lysozyme) were significantly stronger than those of bioavailable metals and soil physical and chemical properties. PICRUSt analysis revealed that the different forms of V and Cd had significantly greater effects on microbial metabolic pathways than all forms of Cr. Cr mainly affected the two major metabolic pathways: microbial cell growth and division and environmental information transmission. In addition, significant differences in rhizosphere microbial metabolism under different concentrations were found, and this can serve as a reference for subsequent metagenomic analysis. This study is helpful for exploring the threshold for the growth of crops in toxic HM soils in mining areas and achieving further biological remediation. [ABSTRACT FROM AUTHOR]

This paper attempts to review the environmental geochemical characteristics (re.: enriched elements) in coals of the Late Permian Xuanwei Formation of NW Yunnan, China, and gauge the possible existence of significant relationships with the incidence and distribution of lung cancer in the region. To achieve this goal, 27 samples were collected in this region; the mineralogical characteristics and major and trace elements were analysed; the Pb isotopic composition was traced; the contribution of the source rock was calculated; and principal component analysis (PCA) was carried out. Our current findings are summarized as follows: (1) the minerals are mainly quartz (silica), chamosite, calcite and kaolinite; (2) MnO, SiO2, V, Cr, Co, Ni, Cu, Cd and W are enriched; (3) the LREYs (La, Ce, Pr, Nd, Pm, Sm and Eu) and HREYs (Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) have similar enrichment degrees, and the fractionation degree of HREYs is higher than that of LREYs; (4) the source distance restricts the Pb isotope composition; (5) MnO, V, Cr, Co, Ni, Cu and Cd are controlled by the Emeishan basalt; the origin of SiO2 (authigenic quartz) is unclear; (6) the lung cancer tissue characteristics, PCA, and toxicological characteristics of elements suggest that the main components of enriched elements probably come from V, Cr, Co, Ni and Cd, not SiO2. In conclusion, the carcinogenic elements V, Cr, Co, Ni and Cd may be related to lung cancer. Since our study is highly explorative, this result leaves many interesting aspects to be further studied. Thematic collection: This article is part of the Geochemical processes related to mined, milled, or natural metal deposits collection available at: https://www.lyellcollection.org/topic/collections/geochemical-processes-related-to-mined-milled-or-natural-metal-deposits Supplementary material: The coal mine and coal sample description, major, trace elements, and XRD results of coal as well as regional geological map are available at https://doi.org/10.6084/m9.figshare.c.6444476 [ABSTRACT FROM AUTHOR]

The oxidation/weathering of molybdenite (MoS2) is too slow to be monitored, even under pure oxygen and high temperatures, while it proceeds rapidly through humid air. The adsorption of water molecules on molybdenite is necessary for the wet oxidation/weathering of molybdenite. Therefore, we employ kinetic Monte Carlo modeling to clarify the adsorption isotherm, site preferences and kinetics of water on different surfaces of molybdenite. Our results indicate that (1) the adsorption capacity and adsorption rate coefficient of H2O on the (110) surface are significantly larger than those on the (001) surface at a temperature of 0~100 °C and a relative humidity of 0~100%, suggesting that the (110) surface is the predominant surface controlling the reactivity and solubility of molybdenite in its interaction with water; (2) the kinetic Monte Carlo modeling considering the adsorption/desorption rate of H2O, dissociation/formation rate of H2O and adsorption/desorption of dissociated H indicates that the adsorption and dissociation of H2O on the (110) surface can be completed in one microsecond (ms) at 298 K and in wet conditions; (3) the adsorption and dissociation of H2O on molybdenite are not the rate-limiting steps in the wet oxidation/weathering of molybdenite; and (4) kinetic Monte Carlo modeling explains the experimental SIMS observation that H2O and OH (rather than H+/H− or H2O) occupy the surface of MoS2 in a short time. This study provides new molecular-scale insights to aid in our understanding of the oxidation/weathering mechanism of molybdenite as the predominant mineral containing molybdenum in the Earth's crust. [ABSTRACT FROM AUTHOR]

The paleosedimentary environment and paleoclimate of the Neogene Guantao Formation in the Liaodong sub-uplift of Bohai Bay Basin in China, which is an important oil and gas exploration horizon, are not clear owing to the lack of quantitative analysis. The paleosedimentary environment and paleoclimate can be qualitatively or semi-quantitatively reconstructed by sedimentary geochemical indicators sensitive to the environment and climate. Based on the evaluation of whether the elements and isotopes can effectively record paleosedimentary environment and paleoclimate information or not, the paleoclimate (temperature and humidity), paleoenvironment (salinity, water depth, redox conditions), and evolution of the paleoenvironment and paleoclimate are studied by analyzing the trace elements, carbon and oxygen isotopes, strontium isotopes, whole-rock mineral compositions, and clay minerals of mudstones of the Guantao Formation in the Liaodong sub-uplift, Bohai Bay Basin. The study results show that (1) according to the trace element distribution patterns, high concentrations of continental elements (Ti, Zr, Th), clay minerals, and detrital content, the Guantao Formation is a product of proximal deposits, and the provenance mainly originates from the intermediate–acidic magmatic rocks near surrounding uplifts. (2) The paleoclimate during the sedimentation of the Guantao Formation was mainly semi-arid and semi-humid, as revealed by the Sr/Cu ratio. However, the high Rb/Sr and 87Sr/86Sr ratios demonstrate that the paleoclimate is relatively warm and humid. (3) The paleosedimentary temperature calculated by the Sr content and δ18O is roughly 30 °C, indicating that the Guantao Formation was deposited in a subtropical to tropical climate. (4) The Guantao Formation was deposited in continental freshwater according to the Li, Ni, and Sr content, Sr/Ba ratios, 87Sr/86Sr ratios, and salinity index Z. (5) The water depth of the paleoenvironment of the Guantao Formation is mainly in nearshore shallow water, reflected by the Mn/Ti ratio and calculated by the Co content, and the oxidizing condition of the paleoenvironment of the Guantao Formation, reflected by the U/Th, V/Cr, and Ni/Co ratios, is in a good coupling relationship with this environment. (6) As revealed by the variations in the geochemical data in the section, the temperature, humidity, and water depth of the Guantao Formation gradually increased from the early to late period, while the salinity gradually decreased, and the chemical weathering effect gradually increased. [ABSTRACT FROM AUTHOR]

The ophiolites along the North Qilian Orogenic Belt are considered to be fragments of ancient oceanic crusts and lithospheric mantle of the Palaeozoic North Qilian Ocean (a branch of the Proto‐Tethys). Compared with other ophiolites in this belt, the genesis of the Xiejiayao ophiolite has been poorly studied so far, making it difficult to understand the tectonic evolution of the ocean. In this study, we present new compositional and Sr‐Nd isotopic analyses of basaltic rocks from the Xiejiayao ophiolite to shed light on its petrogenesis and geodynamic background. These oceanic basalts are characterized by flat REE patterns, low elemental ratios of high‐field‐strength elements (e.g., La/Sm, Sm/Yb, La/Yb, Gd/Yb, [Th/Yb]PM) and abundant spinels, implying that they were generated via partial melting in the spinel stability field of the mantle. Their positive εNd(t) values (6.1–8.4), high Zr/Nb (43.65–79.40) as well as low Nb/Ta (10.91–15.09), Zr/Hf (34.64–39.28), and Nb/Yb (0.41–0.59) ratios further reflect that the ancient mantle had already become depleted to some extent before the onset of the Palaeozoic ocean. Additionally, basalts share many geochemical similarities (e.g., Zr, Y, Ti, and V) with both mid‐ocean ridge and island arc basalts. This supports the strong likelihood of origin in a back‐arc basin close to the suprasubduction zone for the ophiolite. Therefore, accompanied by the northward subduction of the oceanic lithosphere during the early Palaeozoic, a large‐scale back‐arc basin developed progressively in response to the back‐arc expansion. The Xiejiayao basaltic magmas were generated in the back‐arc basin via partial melting of the depleted mantle and their source was probably mixed with subducted melts/fluids from the dehydration and melting of oceanic slabs and sediments. [ABSTRACT FROM AUTHOR]

Accumulating heavy metal contamination in soils caused by industrial waste, fertilizer, and wastewater irrigation is a matter of grave concern for the environment and food safety. In recent years, remediation agents with the characteristics of economy, high efficiency, and simple operation have become a popular choice for remediation of heavy metal contaminated soil. By far, there are relatively few studies evaluating the effects on remediation agents for their both heavy metal passivation and soil fertility promotion. This study investigated the effects of a remediation agent on Cd passivation, soil pH, and heavy metal uptake by rice crops. Eight treatments were used to evaluate the effect of Cd immobilization in soil. Changes in soil pH and soil Cd fractions were monitored during incubation for 30 days. The field study was conducted during the whole growth stages of rice crops, samples of rice plants and soil at the tillering, booting, and harvesting stages were collected and tested. Cd fractions were extracted from soil at different stages to investigate the effects of various treatments on Cd uptake and bioaccumulation in rice plants. The results show that composite mineral remediation agents composed of mineral fertilizer and synthetic zeolite could effectively improve the pH of soil in incubation experiments and field experiments. Composite mineral remediation agents were effective in stabilizing Cd and increasing rice yield. Mineral fertilizer and Synthetic zeolite played an important role in the tillering stage and harvesting stage of rice growth in field, respectively. Group A4 (mineral fertilizer: synthetic zeolite at mass ration of 10:6) had the best results. Compared with control experiment (CK), HOAc extractable Cd of A4 group decreased by 6%, oxidizable Cd of A4 group increased by 2%, and the residue Cd of A4 group increased by 4%. [ABSTRACT FROM AUTHOR]

Isolating relevant microorganisms is still a substantial challenge that limits the use of bacteria in the maintenance of human health. To confirm which media and which bacterial colony densities can enrich certain kinds of bacteria, we selected eight common media and used them to enrich the gut microorganisms on agar plates. Then, we calculated the numbers of bacterial colonies and collected the bacterial culture mixtures from each kind of medium. Using the Illumina HiSeq platform, we analyzed the composition and diversity of the culture-enriched gut bacterial community. Our data suggested that medium supplemented with blood could increase the diversity of the bacterial community. In addition, beef powder and peptone could significantly change the culture-enriched bacterial community. A moderate density (100–150 colony-forming units per plate) was optimal for obtaining the highest diversity on the agar. Similarly, membrane transport was significantly enriched in the moderate-density group, which indicated a more active metabolism in this density range. Overall, these results reveal the optimal culture conditions, including the densities of colonies and nutritional components for various gut bacteria, that provide a novel strategy for isolating bacteria in a way that is targeted and avoids blinded and repetitive work. [ABSTRACT FROM AUTHOR]

This paper attempts to reveal the characteristics and influencing factors of air pollution in Sichuan Basin. To solve the air pollution problem and gain some implications, six criteria air pollutants and six meteorological parameters were counted; local statistical data at the provincial level were acquired in 2018; the temporal-spatial distribution contour map of monthly mean PM2.5 concentrations was drawn; the monthly trends of PM2.5, PM10, and O3 were analyzed; the monthly mean six criteria air pollutants and six meteorological parameters at the basin scale were established by Spearman's correlation analysis and hierarchical agglomerative cluster analysis (HACA); and the annual mean air pollutants and local statistical data at the city scale were calculated by Spearman's correlation analysis. The results implied that (1) PM2.5, O3, and PM10 were the dominant air pollutants; (2) Chengdu (CD), Zigong (ZG), Deyang (DY), Mianyang (MY), Yibin (YB), and Dazhou (DZ) were the cities with the worst air quality; (3) December, January, and February were the worst months; (4) the air pollution tends to spread from type-I cities to type-IV cities; (5) temperature and precipitation were important predictors which were correlated with pollutants strongly; and (6) the main sources of air pollution originated from anthropogenic activity, such as PM2.5 from the emission of industrial enterprises and PM10 from vehicle traffic. Finally, we give some recommendations. [ABSTRACT FROM AUTHOR]

We attempt to understand the pollution characteristics and carcinogenic risk of toxic elements around Hutou Village, Xuanwei City, Yunnan Province, China. For this propose, 48 road dust samples were collected systematically, and the concentrations of Cr, Ni, Cu, Zn, As, Cd, Pb, Co, and Cr(IV) were analyzed and compared; the spatial distribution was obtained. The Igeo and EF indices and multivariate statistical analysis (CA, PCA, HACA) were carried out for source investigation, and human health risk assessment was also adopted to evaluate local non-carcinogenic and carcinogenic risks. The result showed that Cr, Ni, Cu, Cd and Co contaminations were quite serious; Zn, As, Cd, and Pb had similar distribution pattern, and Cr and Ni also shared similar distribution characteristics; Cd, Pb, Zn, and As ascribed to anthropogenic sources, while Cr and Ni originated from either anthropogenic activity or natural sources; Co and Cu originated from natural sources; the non-carcinogenic risk of Co cannot be ignored. The carcinogenic risk of Ni was considered unacceptable. Finally, an indoor coal-burning pattern was established that the high Cd and Ni inhalation and ingestion model was associated with lung cancer. [ABSTRACT FROM AUTHOR]

Chengdu, a megacity in southwestern China, experiences severe air pollution; however, knowledge of the seasonal variation in mass concentration, extent of potentially harmful elements (PHEs) contamination, and sources caused by heavy metals remains lacking. This study adopted a weighting method to calculate the daily mass concentration of PM1 and used ICP-MS to determine PHE concentrations. Results indicated that PM1 mass concentration was in the range 5.44–105.91 μg/m3. Seasonal PM1 mass concentration could be arranged in the following order: winter > fall > spring > summer. The concentrations of PHEs in the PM1 sample mostly showed the same seasonal variation characteristics as mass concentration. The average concentration of each PHE decreased as follows: Cu (107.44) > Zn (81.52) > Pb (22.04) > As (8.17) > Sb (1.91) > Ni (1.87) > Cr(VI) (0.84) > Cd (0.40) > Tl (0.33) (ng/m3). Enrichment factor values varied markedly from mild to anomalous enrichment. Principal component analysis revealed mainly derived from the fossil fuel combustion (55.215%). [ABSTRACT FROM AUTHOR]

This paper systematically studied the mass concentration levels of PM2.5 and PM10 and obtained the morphological characteristics and components of the particles through scanning electron microscopy (SEM–EDX) and discussed the sources of the particles. Meanwhile, the health risk was evaluated according to the mass concentration of particulate matter. The results showed that the average annual PM2.5 and PM10 in the eastern part of Chengdu were 101.99 μg/m3 and 168.89 μg/m3, respectively, exceeding the national second-level average annual air quality standard (GB3095-2012). Both of them were the highest in winter and the lowest in summer and had a significant positive correlation. The atmospheric particles in the study area were mainly composed of fly ash particles, soot aggregates, mineral particles (sulfate mineral particles, carbonate mineral particles, etc.), which mainly came from coal burning, dust, automobile exhaust and secondary products. The results of the health risk assessment showed that the mass concentration of PM2.5 and PM10 in the atmosphere of the eastern part of Chengdu exceeded the IT-1 target. The average annual air quality index was 185.84, and the air quality index was level 4, classified as medium pollution. PM10 and PM2.5 were both excessive pollutants, and PM10 was the primary pollutant. Relevant measures should be taken to control particulate matter sources to some extent. [ABSTRACT FROM AUTHOR]

To clarify the mechanism controlling the migration of uranium and typical heavy metals at the sediment–water interface, four sampling cores were collected along the Mianyuan River near a phosphate mining region to investigate their distribution in pore water and sediment along vertical profiles. This study indicated that: (1) the average concentrations of U, Cd, Cu, Pb, Zn and Ni in the pore water were 2.17, 0.08, 6.28, 1.78, 80.56 and 5.18 µg l−1 , respectively, some of them being higher than the National Recommended Water Quality Criteria. (2) The enrichment of U, Cu, Pb, Zn and Ni in the sediment near the urban area clearly indicated that local industries were important pollution sources. (3) The average diffusive fluxes of U, Cd, Cu, Pb, Zn and Ni of the four profiles were 0.016, 0.007, 0.300, 0.022, 2.925 and −1.328 µg/(m2·d), indicating that most of the metals diffused from the sediment pore water to the overlying water. (4) The IWCTU (Interstitial Water Criteria Toxic Units) values of Pb in the pore water exceeded 1 in most river sections, indicating that the toxicity levels in the sediments presented a risk to aquatic organisms. [ABSTRACT FROM AUTHOR]

The 87Sr/86Sr minimum of the Capitanian seawater is one of the most significant features in the Phanerozoic seawater 87Sr/86Sr history. In order to assess possible contribution of the Emeishan large igneous provinces (LIPs) to strontium isotope evolution of the Capitanian seawater, 87Sr/86Sr ratios were measured from the Capitanian limestones which are locally interlayered with the Emeishan basalts. The limestones underlying the Emeishan basalts have high 87Sr/86Sr ratios (0.7070–0.7074). However, extremely low 87Sr/86Sr ratios (0.7068–0.7070) were identified in the late Capitanian Jinogondolella prexuanhanensis–J. xuanhanensis zones, which correspond to the eruption time of the Emeishan LIP. The temporal coincidence of these two phenomena supports the idea of a potential linkage between Capitanian 87Sr/86Sr minimum and eruption of this igneous province. The strong submarine hydrothermal activity and erosion of the Emeishan LIP could have released large amounts of non-radiogenic Sr to the oceans and play an important role in strontium isotope evolution of the seawater. [ABSTRACT FROM AUTHOR]

In this study, the loaded diatomite was prepared with Changbai Mountain diatomite as the carrier according to different Fe/Al molar ratios. The structure and adsorption of the above materials were characterized by XRD, SEM, and ICP-OES. The effects of Fe/Al molar ratio, adsorption time, initial concentration of V(V), and the initial pH value of the solution on the adsorption performance of loaded diatomite were explored. The diatomite loaded with Fe/Al compounds could significantly improve the removal efficiency of V(V), and the removal efficiency of loaded diatomite prepared according to a Fe/Al molar ratio of 1:3 was better. Reaction equilibrium time is 24 h and the pseudo second-order kinetic equation can better describe the adsorption kinetic behavior of V(V) on loaded diatomite. When the initial concentration of V(V) increased from 15.85 mg/L to 122.5 mg/L, the unit adsorption capacity and removal rate of V(V) by loaded diatomite increased continuously. The adsorption behavior of V(V) on loaded diatomaceous earth belongs to the chemical adsorption via the multi-molecular layer, which is consistent with the Freundlich isotherm adsorption model. A weak acid environment is beneficial to the adsorption behavior of V(V) on loaded diatomaceous earth and the strong alkaline environment should be avoided. [ABSTRACT FROM AUTHOR]

The nanoakaganeite (β-FeOOH) was synthesized by the hydrothermal method in the study. The structural characterization and adsorption investigation of the produced materials were performed with powder X-ray diffractometer (XRD), scanning electron microscope (SEM), and inductively coupled plasma optical emission spectrometer (ICP-OES). Moreover, the influences of hydrothermal time, Fe3+ concentration, and hydrothermal temperature on the product structure and chromium adsorption were investigated. In addition, the influence of initial Cr(VI) concentration on chromium adsorption was investigated. The investigation results confirmed the optimal synthesis conditions of β-FeOOH as follows: 72 h hydrothermal reaction, 0.20 M Fe3+, and hydrothermal temperature at 70 °C. The as-synthesized β-FeOOH was spindle-shaped akaganeite. When the initial Cr(VI) concentration increased from 9.91 mg/L to 99.47 mg/L, the adsorption capacity increased and Cr(VI) removal rate decreased. Cr(VI) adsorption on β-FeOOH was a single-molecule layer chemical adsorption, conforming to the Langmuir adsorption model. The maximum saturation adsorption was 16.35 mg/g. [ABSTRACT FROM AUTHOR]

In this study, 2LFh was synthesized, and the effects of 2LFh synthesis in the laboratory as well as its synthetic products’ mineral crystal phase changes during high temperature aging process caused by Ca2+, Mg2+, and Cl− were also studied. In addition, the Cd2+ adsorption effects of the products above with different pH values and different Cd2+ concentrations were studied in this experiment. The results showed that the existence of Ca2+ had no significant effect on the synthesis and aging of 2LFh. However, in the presence of Mg2+ and Cl−, the akaganeite could be found in the synthetic material, and with the increase of the ion concentration, the crystallinity of the formed akaganeite was higher. And akaganeite had a significant inhibitory effect on the aging of 2LFh, causing the Cd2+adsorption effect of 2LFh after aging was better than that of pure 2LFh. The adsorption and removal rates of Cd2+ in Fh2 series and Fh2-200 series were increased with the increase of initial concentration. With the increase of pH, the adsorption capacity and removal rate were increased, and the removal rate reached nearly 100% when pH value is ranging from 10 to 11. The isothermal adsorption experiment showed that the isothermal adsorption process of Cd2+ in Fh2 series and Fh2-200 series was in accordance with the Freundlich model. The affinity coefficient (Kf) of the Freundlich model of Fh2-200 series arranged in descending order is Fh2-200-Mgs> Fh2-200-Cas> Fh2-200s, showing that the Cd2+ adsorption capacity of Fh2-200 was relatively weak, while that of Fh2-200-Ca series and Fh2-200-Mg series was relatively strong, which was confirmed by the experimental results. [ABSTRACT FROM AUTHOR]

High‐precision measurement of X‐ray spectra is affected by the statistical fluctuation of the X‐ray beam under low‐counting‐rate conditions. It is also limited by counting loss resulting from the dead‐time of the system and pile‐up pulse effects, especially in a high‐counting‐rate environment. In this paper a detection system based on a FAST‐SDD detector and a new kind of unit impulse pulse‐shaping method is presented, for counting‐loss correction in X‐ray spectroscopy. The unit impulse pulse‐shaping method is evolved by inverse deviation of the pulse from a reset‐type preamplifier and a C‐R shaper. It is applied to obtain the true incoming rate of the system based on a general fast–slow channel processing model. The pulses in the fast channel are shaped to unit impulse pulse shape which possesses small width and no undershoot. The counting rate in the fast channel is corrected by evaluating the dead‐time of the fast channel before it is used to correct the counting loss in the slow channel. [ABSTRACT FROM AUTHOR]

To explore geochemical factors affecting the chronological reconstruction of a historical arsenic pollution accident in Lake Qionghai at southwest of China, heavy metals and radionuclides (210Pbexand137Cs) in two sediment cores were sampled and analyzed. Our study revealed that (1) industrialization and urbanization of Xichang since the mid-20thCentury, aggravated soil erosion in the catchment and resulted in a significant and lasting increase in the sedimentation rate of Lake Qionghai; (2) sharp arsenic peaks in two sediment cores recorded an arsenic pollution accident in 2006 in which a large amount of arsenic was discharged into the lake from a chemical plant. Arsenic peaks in sediment cores A and B were dated to 1988 ± 3.5, 2006 ± 3.1, respectively. Only the arsenic peak time in core B: 2006 ± 3.1, agreed with the real pollution accident time of 2006. Linear correlation analysis suggested that arsenic sorption by Fe/Mn minerals and organic materials in sediment core A probably changed the depth distribution of the peak and affected the accuracy of chronological reconstruction. This case study suggested that sorption of heavy metals by Fe/Mn minerals and organic materials should be assessed before the chronological reconstruction of the metal pollution accident in the lake. [ABSTRACT FROM AUTHOR]

Cu-Au mineralization is rare in the Jurassic-Early Tertiary batholiths related to the India-Asia collision. Geochemical analysis and U-Pb isotope chronology was carried out on Shuangbujiere biotite hornblende granodiorite from the Zedong area. Zircon grains of the biotite hornblende granodiorite show oscillatory growth zonation and have high Th/U ratios of 1.08-2.39, indicating a magmatic origin for the zircons. Geochrological test yielded a LA-ICP-MS U-Pb age of 51.5±1.0 Ma, suggesting that the emplacement age of the biotite hornblende granodiorite is Early Eocene. The Shuangbujiere biotite hornblende granodiorites have geochemical features characteristic of adakite and are associated with a calc-alkaline metaluminous I-type granite enriched in Sr, high in Mg# (49.6-54.9) and Sr/Y, and depleted in Y and Yb. These results indicate that this intrusion formation may have been associated with crustal thickening caused by the early collision of the Indian and Eurasian Plates. As the process of crustal thickening continued, the heating of the underplated basaltic magma caused the thickened lower crust amphibolite to dehydrate the melt and form a high-K calc-alkaline adakitic melt at about 848°C. Meanwhile, magma mixing of the underplated basaltic melt and high-K calc-alkaline adakitic melt formed a high-Mg# adakite representative of the sys-collisional tectonic setting. [ABSTRACT FROM AUTHOR]

The article describes a bienzyme visual system for aptamer-based assay of Hg(II) at nanomolar levels. The detection scheme is based on the finding that Hg(II) ions captured by aptamer-functionalized magnetic beads are capable of inhibiting the enzymatic activity of uricase and thus affect the formation of HO and the blue product, i.e., oxidized tetramethylbenzidine. This strategy allows for a visual detection of Hg(II) at nanomolar levels without additional amplification procedure. Measuring the absorbance at 650 nm, the logarithmic calibration plot is linear in the concentration range of 0.5-50 nM and the limit of detection (LOD) is 0.15 nM. This is as low as the LOD obtained by atomic fluorescence spectrometry (AFS). The ions K, Mg, Na, Ca, Cu, Zn, Fe, Al, Co, AsO , Ni, Cd and Pb do not have a significant effect on color formation. The method was applied to the analysis of (spiked) river water, lake water, mineral water, tap water and certified reference water samples, and the results agreed well with those obtained by AFS or certified values, with recoveries ranging from 97% to 109%. The relative standard deviation for five parallel detections at a 10 nM Hg(II) level is 5.2%. [ABSTRACT FROM AUTHOR]

Ambient PM air samples were collected at two industrial sites and one urban residential site in the mining city of Panzhihua, China, from April, 2014, to January, 2015. Mass concentrations of ten trace metals (As, Cd, Cr, Ni, Co, V, Mn, Cu, Pb, and Zn) in PM were determined by inductively coupled plasma-mass spectrometry. The results showed Zn, Pb, Cu, Mn and V were the most abundant elements from the industrial sites. Concentrations for Cd, Cr, Co, Ni, Mn and Cu at industrial sites greatly exceeded the air quality standards of the World Health Organization and the Chinese Ministry of Environmental Protection. Principal component analysis indicated that the main sources of the trace metals were steel smelting, fuel combustion, geological and mineral dust. Four different clusters of particles (i.e., mineral, calcium-containing, soot and aluminosilicate) were identified by scanning electron microscopy coupled with energy dispersive X-ray spectrometry. Chromium (Cr) was found to present the highest excess cancer risk, implying the potential for carcinogenic health effects in local inhabitants. Manganese (Mn) presented a non-carcinogenic health risk to children and adults, while the other metals were within acceptable limits. [ABSTRACT FROM AUTHOR]

This article describes a nonenzymatic chemiluminescence resonance energy transfer (CRET) system for highly sensitive determination of hydroquinone. It was found that the Co(II)-catalyzed luminescence of luminol in pH 11.5 solution is transferred to CdTe quantum dots (QDs) via a CRET mechanism. Hydroquinone is oxidized by HO to benzoquinone which quenches the fluorescence of the QDs. The enhancement is attributed to the adsorption of Co(II) on the surface of the negatively charged QDs. The CRET system was applied in an assay for hydroquinone that has a detection limit of 0.17 nmol L. The detection limit was lower by factors between 100 and 250,000 than earlier reported methods. The assay was successfully applied to the quantitation of hydroquinone in (spiked) water samples, with recoveries ranging from 95 % to 106 %, and relative standard deviations between 0.5 % and 2.4 %. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The Maoniuping rare earth elements deposit is the second largest rare earth elements deposit in China, and the third largest in the world. A sediment core was collected from the river floodplain downstream from the Maoniuping rare earth elements mining area (Sichuan Province, China) to reconstruct the cadmium contamination history and trace its contamination source. Based on lead-210 (210Pb) dating by gamma ray spectrometry and elements determination with inductively coupled plasma mass spectrometry of the sediment core, it was found that the cadmium accumulation rate of the flood plain increased from 0.16 to 2.22 µg cm−2yr−1over the past 100 years. Combining aspects of time, space, and element composition information, it is proved that the exploitation of Maoniuping rare earth elements deposit was the main reason for the increase. Moreover, to evaluate the mobility and availability of cadmium in the sediment core, the modified European Communities Bureau of Reference sequential extraction procedure in combination with inductively coupled plasma mass spectrometry was applied. Risk assessment code was used to further assess the environmental risk of cadmium in the sediment. It was found that the environmental risk from cadmium was high in the surface of the sediments. The results from gamma ray spectrometric and mass spectrometric methods may provide important information for the control and remedy of cadmium-related pollution areas. [ABSTRACT FROM PUBLISHER]

Metal contamination in sediment of the Mianyuan River (one of the major upper reaches of the Yangtze River) in Longmenshan Region (China) was investigated in 2012. Means of metal concentrations in sediment (<74μm) were Cr: 59.93 ± 19.8% mg/kg; As: 7.21 ± 50.2% mg/kg; Se: 0.45 ± 66.3% mg/kg; Pb: 19.89 ± 29.3% mg/kg; Zn: 78.98 ± 31.9% mg/kg; Cd: 0.69 ± 28.3% mg/kg; Ba: 0.71 ± 34.0% g/kg; Mn: 0.55 ± 62.2% g/kg. This study suggested: (1) concentrations of Cd, As, Cr, and Pb in Mianyuan River sediment were lower than those of the middle and lower reaches of the Yangtze River; (2) the increase of metals during the period from 2006 to 2009 was probably related to the destruction of tailings piles by the Wen Chun earthquake in 2008; (3) organic materials decided the distribution of Cd, Se, As, Ba, and Mn in the upstream sediment, while the iron and manganese minerals controlled the distribution of Ba, Cr, and Zn in the downstream sediment; (4) sources of Cd, Se, and As were geogenic, while sources of Cr, Zn, Ba, and Mn were anthropogenic; (5) the source of Pb in the upstream sediment was probably automobile exhaust, but that of Pb in the downstream sediment was geogenic. [ABSTRACT FROM AUTHOR]

The carbonaceous-siliceous-argillitic rock type uranium deposit in the Zoige area is located in the northeastern margin of the Tibetan Plateau, and has gained much attention of many geologists and ore deposit experts due to its scale, high grade and abundant associated ores. Because of the insufficient reliable dating of intrusive rocks, the relationship between mineralization and the magmatic activities is still unknown. In order to study this key scientific issue and the ore-forming processes of the Zoige uranium ore field, the LA-ICP-MS zircon U-Pb dating of magmatic rocks was obtained: 64.08±0.59 Ma for the granite-prophyry and ∼200 Ma for the dolerite. U-Pb dating results of uraninite from the Zoige uranium ore field are mainly concentrated on ∼90 Ma and ∼60 Ma. According to LA-ICP-MS U-Pb zircon dating, the ages for the dolerite, porphyry granite and granodiorite are 200 Ma, 64.08 Ma approximately and 226.5-200.88 Ma, respectively. This indicates that the mineralization has close relationship with activities of the intermediate-acidic magma. The ages of the granite porphyry are consistent with those uraninite U-Pb dating results achieved by previous studies, which reflects the magmatic and ore-forming event during the later Yanshanian. Based on the data from previous researches, the ore bodies in the Zoige uranium ore field can be divided into two categories: the single uranium type and the uranium with polymetal mineralization type. The former formed at late Cretaceous (about 90 Ma), while the latter, closely related to the granite porphyry, formed at early Paleogene (about 60 Ma). And apart from ore forming elemental uranium, the latter is often associated with polymetallic elements, such as molybdenum, nickel, zinc, etc. [ABSTRACT FROM AUTHOR]

The effects of rhizodeposition on soil C and N availabilities lead to substantial changes of microbial community composition and processes in the rhizosphere of plants. Under heterogeneous light, photosynthates can be translocated or shared between exposed and shaded ramets by clonal integration. Clonal integration may enhance the rhizodeposition of the shaded ramets, which further influences nutrient recycling in their rhizosphere. To test the hypothesis, we conducted a pot experiment by the stoloniferous herb Glechoma longituba subjected to heterogeneous light. Microbial biomass and community composition in the rhizosphere of shaded offspring ramets, assessed by phospholipid fatty acids (PLFAs) analysis, were markedly altered by clonal integration. Clonal integration positively affected C, N availabilities, invertase and urease activities, N mineralization (Nmin) and nitrification rates (Nnitri) in the rhizosphere of shaded offspring ramets. However, an opposite pattern was also observed in phenoloxidase (POXase) and peroxidase (PODase) activities. Our results demonstrated that clonal integration facilitated N assimilation and uptake in the rhizosphere of shaded offspring ramets. The experiment provides insights into the mechanism of nutrient recycling mediated by clonal integration. [ABSTRACT FROM AUTHOR]

The isotopic composition and parameters for deuterium excess of brines, which were sampled in the Sichuan Basin, show obvious regularities of distribution. The brine isotopic composition shows distinct two systems of marine and terrestrial deposits, with the Middle Triassic strata as the boundary. Brine hydrogen isotopic composition of marine deposits is lower while oxygen isotopic composition is higher than that of the SMOW, respectively, indicating that the brines were derived from seawater with different evaporating degrees at different times. From the Sinian strata, up to the Cambrian, Permian Maokou Formation and the Triassic Jialingjiang Formation, the δD values of brines tend to become relatively positive with the strata becoming younger. Brines of terrestrial deposits are considered to have been derived from precipitation and their isotopic composition is close to the globe meteoric water line (GMWL). Brines of transitional deposits between marine and terrestrial ones (the Upper Triassic Xujiahe Formation) have δD and δO values falling between the two end members of marine deposit brines and precipitation, indicating that the brines are a mixture of precipitation and vaporing seawater. Water samples from the brine-bearing strata of different ages show various deuterium excesses ( d) with an evident decreasing trend as the age of strata gets older and older. Brine-bearing strata of the Triassic Leikoupo-Jialingjiang Formation, the Permian Maokou Formation, the Cambrian and Sinian strata are all carbonate rocks which have experienced intensive water/rock reaction and the deuterium excess essentially changes with time. All brine-bearing-strata surrounding the basin or faults, as well as those brine wells exploited for resources, have been obviously influenced by the precipitation supply. Therefore, the deuterium excesses of their brines have increased to different extents, depending on the amount of involvement of meteoric water. The variation and distribution of d values of the brines from different Triassic strata are related to the embedded depth of the strata. The deuterium excesses of brines become lower with increasing burial depth of the strata. [ABSTRACT FROM AUTHOR]

A baseline might be used as a point of reference to monitor change from some specific data without concern for whether the baseline determination is natural or has been changed by human activity. We selected 326 sediment samples from Dexing area, South China, and analyzed for 17 chemical elements. The geochemical baseline was predicted with the method of the normalization procedure combined with the relative cumulative frequency curve. The results indicate Al was the best reference element for the normalization procedure among four potential reference elements (Al, Fe, Ti, and Mn). The baseline value range obtained from the normalization procedure method included both the regional geochemical background of the sediment and the median value of the measured contents. The median value of baselines obtained from relative cumulative frequency method was lower than that obtained from normalization procedure method. In contrast to the geochemical patterns of heavy metals in 1987, the spatial distribution of anomalies sprawled in 2004 in study area, especially for Cu, Pb, Zn, Cd, As, Fe, and Cr. [ABSTRACT FROM AUTHOR]

Vanadium is a trace element widely distributed in the Earth’s crust. Naturally high levels of vanadium are recognized mainly in basic rocks and minerals, particularly in titaniferous magnetite. And the anthropogenic sources of vanadium include fossil fuel combustion and wastes including steel-industry slags. In the last few years, the authors have made investigations and assessments on the environmental geochemistry and ecological risk of vanadium in the Panzhihua mining and smelting area. In the study area, anthropogenic vanadium resulted from mining, extracting and smelting of V-Ti magnetite; vanadium pollution of topsoil and sediments occurs mainly in the mining and extracting area, smelting area, slag dumping area, tailing dam and coal mining area. In the soil, the chemical speciation of vanadium shows: insoluble residue > organically bound > Fe (amorphous) oxide-bound > Mn oxide-bound > soluble component. Vanadium pollution can cause potential harmful effects on ecological systems, and lead to animal poisoning and human disease. So vanadiam pollution should be monitored on a regular basis in the Panzhihua area. [ABSTRACT FROM AUTHOR]

An eco-environmental geochemical investigation was carried out in and around the Dexing mining area to determine the concentrations of heavy metals in the surface water, sediments, soils and plants. The main objective of this study is to assess the environmental situation and evaluate the transferring of heavy metals from mining activities into the food chain. Some samples of water, sediment, topsoil and plant were collected along the Lean River in the Dexing mining area. The total concentrations of Cu, Pb, Zn, Cd, and As were determined by AAS, and Hg was analyzed by cold-vapor AAS. Some indices such as 'contamination degree', 'geo-accumulation index', and 'biological absorption coefficient' were used to assess eco-environmental quality. The investigation indicated a highly localized distribution pattern closely associated with the two pollution sources along the Le'an River bank: one is strong acidity and a large amount of Cu in the drainage from the Dexing Cu mining area; and the other is the high concentrations of Pb and Zn in the effluents released from many smelters and mining, processing and extracting activities in the riparian zone. Results from the investigated localities indicated, at least in part, that some problems associated with environmental quality deterioration should be solved in the future. [ABSTRACT FROM AUTHOR]

Analyses of fluid inclusion leachates from ore deposits show that Na/Br ratios are within the range of 75 - 358 and Cl/Br 67 - 394, respectively, and this variation trend coincides with the seawater evaporation trajectory on the basis of the Na/Br and Cl/Br ratios. The average Cl/Br and Na/Br ratios of mineralising fluids are 185 and 173 respectively, which are very close to the ratios (120 and 233) of the residual evaporated seawater past the point of halite precipitation. It is suggested that the original mineralizing brine was derived from highly evaporated seawater with a high salinity. However, the inclusion fluid's have absolute Na values of 69.9-2606.2 mmol kg-1 and Cl values of 106.7 - 1995.5 mmol kg-1. Most of the values are much less than those of seawater; Na, 485 mmol kg-1 and Cl, 566 mmol kg-1, respectively; the salinity measured from fluid inclusions of the deposits ranges from 2.47 wt% to 15.78 wt% NaCl equiv. The mineralizing brine has been diluted. The δ18O and δD values of ore-forming fluids vary from -8.21‰ to 9.51‰ and from -40.3‰ to -94.3‰ respectively. The δD values of meteoric water in this region varied from -80‰ to - 100‰ during the Jurassic. This evidenced that the ore-forming fluids are the mixture of seawater and meteoric water. Highly evaporated seawater was responsible for leaching and extracting Pb, Zn and Fe, and mixed with and diluted by descending meteoric water, which resulted in the formation of ores. [ABSTRACT FROM AUTHOR]

Mining and smelting activities are the main causes for the increasing pollution of heavy metals in soil, water body and stream sediment. An environmental geochemical investigation was carried out in and around the Panzhihua mining and smelting area to determine the extent of chemical contamination in soil and sediment. The main objective of this study was to investigate the environmental geochemistry of Ti, V, Cr, Mn, Cu, Pb, Zn and As in soil and sediment and to assess the degree of pollution in the study are. The data of heavy metal concentrations reveal that soils and sediments in the area have been slightly contaminated. Geochemical maps of I[subgeo] of each heavy metal show that the contaminated sites are located in V-Ti-magnetite sloping and smelting, gangues dam. The pollution sources of the selected elements come mainly from dusts resultant from mining activities and other three-waste-effluents. The are needs to be monitored regularly for trace metal, especially heavy metal enrichment. [ABSTRACT FROM AUTHOR]

Presents a study on the kinetic modeling of diagenesis of Eogene Lacustrine sandstone reservoirs in the Jianghan Basin, Southeastern China. Diagenetic features identified in the sandstones; Simulation of the kinetics of fluid-mineral reactions and the concentrations of aqueous species; Result of the weak pore fluid during the early diagenetic stage; Cause of the precipitation of quartz, kaolinite and illite.

Presents a study that determined geochemical baseline models and assessed the contributions of trace elements from natural and anthropogenic sources in the Panzhihua mining area in China. Background on Panzhihua; Adoption of a normalization procedure to establish geochemical baselines; Analytical results and relevant parameters for trace metals in topsoil samples from the area.

Air pollution is becoming increasingly serious along with social and economic development in the southwest of China. The distribution characteristics of particle matter (PM) were studied in Chengdu from 2016 to 2017, and the changes of PM bearing water-soluble ions and heavy metals and the distribution of secondary ions were analyzed during the haze episode. The results showed that at different pollution levels, heavy metals were more likely to be enriched in fine particles and may be used as a tracer of primary pollution sources. The water-soluble ions in PM2.5 were mainly Sulfate-Nitrate-Ammonium (SNA) accounting for 43.02%, 24.23%, 23.50%, respectively. SO42−, NO3−, NH4+ in PM10 accounted for 34.56%, 27.43%, 19.18%, respectively. It was mainly SO42− in PM at Clean levels (PM2.5 = 0~75 μg/m3, PM10 = 0~150 μg/m3), and mainly NH4+ and NO3− at Light-Medium levels (PM2.5 = 75~150 μg/m3, PM10 = 150~350 μg/m3). At Heavy levels (PM2.5 = 150~250 μg/m3, PM10 = 350~420 μg/m3), it is mainly SO42− in PM2.5, and mainly NH4+ and NO3− in PM10. The contribution of mobile sources to the formation of haze in the study area was significant. SNA had significant contributions to the PM during the haze episode, and more attention should be paid to them in order to improve air quality. [ABSTRACT FROM AUTHOR]

Cd and Pb in farmland topsoil are controlled by many factors. To identify the source of potential toxic metals in the farmland topsoil around Mianyuan River, the chemical analysis and multivariate statistical analysis are performed in this study. The results indicate the following: (1) The concentration of Cd and Pb in soil exceed the background value of Chinese soil elements. (2) Cd is significantly enriched in the whole region and Pb is locally enriched, both of them are more or less influenced by human activities. (3) The contents of Cd and Pb increase significantly following the flow direction of river. (4) P b isotope analysis indicates that the main source of Pb in the soil include the air dust, coal and phosphate plant, and the contribution of them decreases successively. (5) Linear correlation analysis and principal component analysis show that the main sources of Cd in the soil are mining phosphate rock, air dust, phosphate plant and coal mining. [ABSTRACT FROM AUTHOR]

The article focuses on a research paper analyzing the platinum-group element (PGE) constraint on the origin mechanism of the Hetaoshu PGE deposit in the Xiaoguanhe Region in Panxi Area, China. The concentrations of PGE, copper and nickel in rock samples show that the ore forming elements consists of nickel and copper. It also evaluates the impact of sulfide segregation on the ore-forming process of Hetaoshu deposit.

The article discusses the research study conducted to examine the geologic history of the iron oxide copper gold (IOCG) deposits in Southwestern China that was associated with polymetallic mineralization. It reveals the age of magmatic rocks and metallogenic epoch and the coupling relationship between polymetallic elements. It also reveals the ore-forming process including the volcanic sedimentation, grenville orogenic event, and superimposed mineralization.

The article discusses a study on lead isotopic geochemistry of Nuri copper-tungsten-molybdenum (Cu-W-Mo) Deposit and highlights its implications in Shannan Area, Southern Tibet, China. It mentions that ore sulphides of Nuri deposit have the same lead isotopic compositions as magmatic rocks. It states that ore sulphides have localized distributions within Gangdese batholith range. It also mentions that ore-bearing intrusions and ore sulphides have lead isotopic composition.