Chromium(III) adsorption removal from acidic solutions by isomeric and tunnel-structural iron oxyhydroxides.

Iron oxyhydroxides for heavy metal treatment have attracted wide attention. In this work, iron oxyhydroxides of isomeric FeOOH (GpI) and tunnel-structural schwertmannite/akaganéite (GpII) were selected to study chromium (Cr(III)) adsorption removal from acidic aqueous solutions by batch experiments, under various reaction time, adsorbate/adsorbent level, pH and anions. Adsorption processes well fitted to pseudo-second-order kinetics (R2 = 0.992-0.999, except for 0.829 for Lep). Isotherm data could be fitted by Langmuir (R2 = 0.901-0.985), Freundlich (R2 = 0.884-0.985) and Temkin (R2 = 0.845-0.961) models at pH 3.7. Langmuir maximum adsorption capacities (mg/g) were 10.4-18.8 (FeOOH, except for 3.08 for Gth2) in GpI, and 20.60/43.40 (Sch-Chem/Sch-Bio) and 12.80/24.70 (Aka-Chem/Aka-Bio) in GpII. Adsorption capacities would gradually increase as Cr(III) concentrations increased within 0-40 mg/L, and could be markedly affected by the SO42- and H2PO4- anions. There were stable adsorption capacities at about pH 3.7, and then increased at pH 3.7-4.1. The Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) results showed that adsorption mechanisms were electrostatic interaction and surface complexation. In addition, three optimal bio-/chem-schwertmannite and lepidocrocite adsorbents had good reusable properties and treating abilities of Cr(III)-polluted waters at pH 4.0. These results could provide a theoretical basis for the application of iron oxyhydroxides in removing Cr(III) from acid wastewaters.

Synergistic effect in simultaneous removal of cationic and anionic heavy metals by nitrogen heteroatom doped hydrochar from aqueous solutions.

Industrial wastewater typically contains both cationic and anionic heavy metals; therefore, their simultaneous removal must be considered to ensure environmental sustainability. Herein, nitrogen heteroatom (N) doped hydrochar derived from corncob was prepared via facile NH4Cl-aided hydrothermal carbonization and used for the simultaneous adsorption of divalent copper (Cu(II)) and hexavalent chromium (Cr(VI)) in aqueous solutions. During hydrothermal carbonization, NH4Cl played a vital role as the porogen and N dopant, which contributed to the efficient adsorption affinity toward coexisting Cu(II) and Cr(VI). The theoretical maximum adsorption capacities of the N-doped hydrochar were determined to be 1.223 mmol/g for Cu(II) and 1.995 mmol/g for Cr(VI), which were much better than those of the pristine hydrochar. Furthermore, in the binary-component system, the synergistic effect between Cu(II) and Cr(VI) significantly promoted the adsorption affinity of N-doped hydrochar, resulting in adsorption capacities for Cu(II) and Cr(VI) 9.48 and 1.92 times higher than those of the single-component system, respectively. A series of adsorption experiments and spectroscopic analyses demonstrated that multiple mechanisms, including electrostatic shielding, cation bridging, and redox reactions, mutually contributed to the synergistic effect in the adsorption of coexisting Cu(II) and Cr(VI). Overall, the N-doped hydrochar proved to be effective in simultaneously removing both cationic and anionic heavy metal pollutants.

Comparison of Plasma Trace Elements Between 2 Captive Humboldt Penguin (Spheniscus humboldti) Populations.

Environmental pollutants and their effect on wildlife health play an important role in the conservation of endangered species and can be clinically relevant in captive animals too. Data on relevant concentrations of trace elements in captive birds with no known exposures are rare. For this study, silver, arsenic, gold, barium, cadmium, cobalt, chromium, copper, iron, mercury, magnesium, manganese, molybdenum, thallium, selenium, and zinc were measured by inductively coupled plasma mass spectrometry in lithium heparinized plasma samples from 18 Humboldt penguins at 2 zoological collections in Germany. The results showed that the plasma concentrations of silver, arsenic, gold, cadmium, cobalt, chromium, mercury, and selenium differed significantly (P ≤ 0.05) between the 2 penguin collections. The results indicate that the location of the birds has a strong influence on the plasma trace element concentrations. Well water used in the enclosures was suspected to be associated with these significant differences. Trace elemental concentrations in feed (eg, marine fish) and contamination from enclosure construction materials may also play a role. This study could provide a basis for further comparative, biomonitoring, toxicity, and reference interval studies.

The concentration of chromium and cobalt ions and parameters of oxidative stress in serum and their impact on clinical outcomes after metaphyseal hip arthroplasty with modular metal heads.

PURPOSE: Current epidemiological data forecast an almost 40% increase in the number of hip arthroplasty performed in the population of patients with osteoarthritis in 2060, compared to year 2018. On the basis of 10 years of observation, the failure rate after a metal-on-metal hip replacement is between 56.7 and 88.9%, depending on the used implant. METHODS: Seventy-six men operated using metaphyseal hip prostheses, with modular metal heads: the J&J DePuy ASR and Biomet Recap-Magnum systems, after a period of about 5-7 years after the procedure, were assessed twice (an interval of 6 months) in terms of the parameters of oxidative stress and the concentration of chromium, cobalt and ions nickel, as well as their impact on the current clinical status and quality of life. RESULTS: The mean values of the Co and Cr ion concentrations increased in a statistically significant manner at the individual stages of the study (13.20 Co and 18.16 Cr) for J&J DePuy ASR. Using the WOMAC-hip, HHS and SF-12 rating scales, the functional status of operated patients in both study groups did not change in a statistically significant manner during subsequent visits. There was a statistically significant increase in perceived pain in patients operated bilaterally with the J&J DePuy ASR system. The severity of pain could be related to the increase in the concentration of Co and Cr ions; however, it concerned a small group of bilaterally operated patients (n = 3 + n = 4). CONCLUSIONS: Metal-on-metal configuration in hip arthroplasty significantly influences with the increase in the concentration of chromium and cobalt ions in a double assessment. A statistically significant increase in the concentration of the tested Co and Cr ions in the blood correlates with an increase in the intensity of pain, especially in patients undergoing bilateral surgery. The limitation of this study is the relatively small number of bilaterally operated patients. Elevated levels of Co and Cr ions in the blood of patients operated on with the J&J DePuy ASR system increased steadily during both follow-up visits.

Ecological risk assessment of trace elements (TEs) pollution and human health risk exposure in agricultural soils used for saffron cultivation.

Contamination of farmland soils by trace elements (TEs) has become an international issue concerning food safety and human health risks. In the present research, the concentrations of TEs including cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn) and iron (Fe) in soils of 16 farmlands were determined in Gonabad, Iran. In addition, the human health risks due to exposure to the TEs from the soils were assessed. Moreover, the soil contamination likelihood was evaluated based on various contamination indices including contamination factor [Formula: see text]), enrichment factor (EF), geo-accumulation index (Igeo), and pollution load index (PLI) calculations. The soil mean concentrations for Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn and Fe ranges as 0.102, 6.968, 22.550, 29.263, 475.281, 34.234, 13.617, 54.482 and 19,683.6 mg/kg in farmland soils. The mean concentrations of the TEs decreased in the order of Fe > Mn > Zn > Ni > Cu > Cr > Pb > Co > As > Cd. Levels of all metals in this study were within the FAO/WHO and Iranian soil standards. The HQ values from investigated elements for adults and children in the studied farms were less than the limit of 1, indicating no health risks for the studied subpopulations. The results of the present research indicated no significant carcinogenic health hazards for both adults and children through ingestion, skin contact and inhalation exposure routes. [Formula: see text] values of Ni and Zn in 100% and 6.25% of farmlands were above 1, showing moderate contamination conditions. EF values of metals in farmlands were recorded as "no enrichment", "minimal enrichment" and "moderate enrichment" classes. Furthermore, it can be concluded that the all farms were uncontaminated except Ni (moderately contaminated) based on Igeo. This is an indication that the selected TEs in the agricultural soils have no appreciable threat to human health.

Epigenetic and epitranscriptomic mechanisms of chromium carcinogenesis.

Hexavalent chromium [Cr(VI)], a Group I carcinogen classified by the International Agency for Research on Cancer (IARC), represents one of the most common occupational and environmental pollutants. The findings from human epidemiological and laboratory animal studies show that long-term exposure to Cr(VI) causes lung cancer and other cancer. Although Cr(VI) is a well-recognized carcinogen, the mechanism of Cr(VI) carcinogenesis has not been well understood. Due to the fact that Cr(VI) undergoes a series of metabolic reductions once entering cells to generate reactive Cr metabolites and reactive oxygen species (ROS) causing genotoxicity, Cr(VI) is generally considered as a genotoxic carcinogen. However, more and more studies have demonstrated that acute or chronic Cr(VI) exposure also causes epigenetic dysregulations including changing DNA methylation, histone posttranslational modifications and regulatory non-coding RNA (microRNA and long non-coding RNA) expressions. Moreover, emerging evidence shows that Cr(VI) exposure is also capable of altering cellular epitranscriptome. Given the increasingly recognized importance of epigenetic and epitranscriptomic dysregulations in cancer initiation and progression, it is believed that Cr(VI) exposure-caused epigenetic and epitranscriptomic changes could play important roles in Cr(VI) carcinogenesis. The goal of this chapter is to review the epigenetic and epitranscriptomic effects of Cr(VI) exposure and discuss their roles in Cr(VI) carcinogenesis. Better understanding the mechanism of Cr(VI) carcinogenesis may identify new molecular targets for more efficient prevention and treatment of cancer resulting from Cr(VI) exposure.

Mechanisms of chromate carcinogenesis by chromatin alterations.

In a dynamic environment, organisms must constantly mount an adaptive response to new environmental conditions in order to survive. Novel patterns of gene expression, driven by attendant changes in chromatin architecture, aid in adaptation and survival. Critical mechanisms in the control of gene transcription govern new spatiotemporal chromatin-chromatin interactions that make regulatory DNA elements accessible to the transcription factors that control the response. Consequently, agents that disrupt chromatin structure are likely to have a direct impact on the transcriptional programs of cells and organisms and to drive alterations in fundamental physiological processes. In this regard, hexavalent chromium (Cr(VI)) is of special interest because it interacts directly with cellular proteins, DNA, and other macromolecules, and is likely to upset cell functions that may cause generalized damage to the organism. Here, we will highlight chromium-mediated mechanisms that disrupt chromatin architecture and discuss how these mechanisms are integral to its carcinogenic properties. Emerging evidence indicates that Cr(VI) targets euchromatin, particularly in genomic locations flanking the binding sites of the essential transcription factors CTCF and AP1, and, in so doing, they disrupt nucleosomal architecture. Ultimately, the ensuing changes, if occurring in critical regulatory domains, may establish a new chromatin state, either toxic or adaptive, that will be governed by the corresponding gene transcription changes in key biological processes associated with that state.

Speciation and distribution of chromium (III) in rice root tip and mature zone: The significant impact of root exudation and iron plaque on chromium bioavailability.

Evidence on the contribution of root regions with varied maturity levels in iron plaque (IP) formation and root exudation of metabolites and their consequences for uptake and bioavailability of chromium (Cr) remains unknown. Therefore, we applied combined nanoscale secondary ion mass spectrometry (NanoSIMS) and synchrotron-based techniques, micro-X-ray fluorescence (µ-XRF) and micro-X-ray absorption near-edge structure (µ-XANES) to examine the speciation and localisation of Cr and the distribution of (micro-) nutrients in rice root tip and mature region. µ-XRF mapping revealed that the distribution of Cr and (micro-) nutrients varied between root regions. Cr K-edge XANES analysis at Cr hotspots attributed the dominant speciation of Cr in outer (epidermal and sub-epidermal) cell layers of the root tips and mature root to Cr(III)-FA (fulvic acid-like anions) (58-64%) and Cr(III)-Fh (amorphous ferrihydrite) (83-87%) complexes, respectively. The co-occurrence of a high proportion of Cr(III)-FA species and strong co-location signals of 52Cr16O and 13C14N in the mature root epidermis relative to the sub-epidermis indicated an association of Cr with active root surfaces, where the dissolution of IP and release of their associated Cr are likely subject to the mediation of organic anions. The results of NanoSIMS (poor 52Cr16O and 13C14N signals), dissolution (no IP dissolution) and µ-XANES (64% in sub-epidermis >58% in the epidermis for Cr(III)-FA species) analyses of root tips may be indicative of the possible re-uptake of Cr by this region. The results of this research work highlight the significance of IP and organic anions in rice root systems on the bioavailability and dynamics of heavy metals (e.g. Cr).

Meta-analysis and health risk assessment of toxic heavy metals in muscles of commercial fishes in Caspian Sea.

Heavy metals from contaminated seafood can have serious consequences for human health. Several studies on the amount of heavy metals in Caspian Sea fish have been conducted to ensure their food safety. This meta-analysis aimed to investigate the levels of five toxic heavy metals; Lead (Pb), Cadmium (Cd), Mercury (Hg), Chromium (Cr), and Arsenic (As) in muscles of commercial fishes of the Caspian Sea with assessing their health risk of developing oral cancer in terms of fish collection place and fish type. A systematic search was performed, and the random effect model was applied for meta-analysis. Finally, 14 studies with 30 different sets of results were included. Our results showed that the pooled estimates for Pb, Cd, Hg, Cr, and As were 0.65 mg/kg (0.52, 0.79), 0.08 mg/kg (0.07, 0.10), 0.11 mg/kg (0.07, 0.15), 1.77 mg/kg (1.26, 2.27), and 0.10 mg/kg (- 0.06, 0.26) respectively. The levels of Pb and Cd were higher than their (FAO/WHO) maximum limits. The Estimated Daily Intake (EDI) of Pb and Cd in Mazandaran, and Hg in Gilan were more than Total Daily Intake (TDI) limits. The consumers' non-carcinogenic risk (THQ) for Hg in Mazandaran and Gilan, and As in Gilan, was unsafe. Carcinogenic risk (CR) for Cr and Cd in all three provinces, and for As in Mazandaran and Gilan, was greater than 1*10 - 4 and was unsafe. The lowest and highest risk levels of oral cancer were for Rutilus kutum and Cyprinus carpio respectively.

Highly photoactive novel NiS/BiOI nanocomposite photocatalyst towards efficient visible light organic pollutant degradation and carcinogenetic Cr (VI) reduction for environmental remediation.

Heterojunction engineering in catalyst structures is a promising approach for solving the main restriction of the narrow photoabsorption range and quick recombination of photogenerated charge carriers in the photocatalysts. Herein, a simple, eco-friendly, non-toxic, and novel Z-scheme heterojunction of nanoflower-like NiS/BiOI was systematically designed using the low-temperature solvothermal and precipitation methods. The physicochemical and photo-electrochemical properties of the as-synthesized nanomaterials were characterized using XRD, FESEM, FT-IR, XPS, BET, UV-vis, PL, and EIS. NiS/BiOI nanomaterials exhibited a wide photoabsorption range (200-1000 nm), a narrow bandgap energy (1.76 eV), a large surface area (35.82 m2 g-1), and a low charge carrier recombination rate because of the synergistic effects of the NiS and BiOI photocatalysts, which could be the basis for superior photocatalytic efficiency. Particularly, the optimal 40% NiS/BiOI nanocomposite exhibited better stability and efficiency than the pure NiS and BiOI. The maximum degradation efficiency of rhodamine B (RhB) was 99.8% after 200 min, tetracycline (TC) was 96.3% after 140 min, and the photoreduction of Cr(VI) was 92.8% after 180 min rather than the pure NiS and BiOI under visible light irradiation. The constant rate (k) of RhB was approximately 10 and 4, TC was 12 and 4, and Cr(VI) was 10 and 8 times that of pristine NiS and BiOI, respectively. Radical trapping experiments and Tauc plot analysis proposed the design of the plausible Z-scheme reaction mechanism between NiS and BiOI, which has a crucial role in the rate of transportation and separation of electron/hole pairs. This investigation provides a venue for the design of a photoactive NiS-based nanocomposite for environmental remediation.

Potential arsenic-chromium-lead Co-contamination in the hilly terrain of Arunachal Pradesh, north-eastern India: Genesis and health perspective.

In the recent times, multi-metal co-contamination in the groundwater of various parts of the globe has emerged as a challenging environmental health problems. While arsenic (As) has been reported with high fluoride and at times with uranium; and Cr & Pb are also found in aquifers under high anthropogenic impacts. The present work probably for the first time traces the As-Cr-Pb co-contamination in the pristine aquifers of a hilly terrain that are under relatively less stress from the anthropogenic activities. Based on the analyses of twenty-two (n = 22) groundwater (GW) samples and six (n = 6) sediment samples, it was found that Cr being leached from the natural sources as evident from 100% of samples with dissolve Cr exceeding the prescribed drinking water limit. Generic plots suggests rock-water interaction as the major hydrogeological processes with mixed Ca2+-Na+-HCO3- type water. Wide range of pH suggests localized human interferences, as well as indicative of both calcite and silicate weathering processes. In general water samples were found high only with Cr and Fe, however all sediment samples were found to contain As-Cr-Pb. This implies that the groundwater is under-risk of co-contamination of highly toxic trio of As-Cr-Pb. Multivariate analyses indicate that the changing pH as the causative factor for Cr leaching into the groundwater. This is a new finding for a pristine hilly aquifers, and we suspect such condition may also be present in other parts of globe, and thus precautionary investigations are needed to prevent this catastrophic situation to arise, and to alert the community in advance.

Skin aging associated with chromium among rural housewives in northern China.

Previous studies have found associations between chromium exposure and skin damage. However, few studies have focused on both chromium and skin aging. This study aimed to assess the degree of skin aging symptoms and estimate the relationship between hair chromium and skin aging among rural housewives. We recruited 405 subjects in Shanxi Province of northern China and analyzed 397 eligible hair samples with inductively coupled plasma-mass spectrometry (ICP-MS). The subjects' skin aging symptoms were assessed with SCINEXA™ (SCore of INtrinsic and EXtrinsic skin Aging). After adjusting for age and other important covariates, the regression results showed more severe skin aging symptoms in women with a higher level of hair chromium and presented an increasing linear trend. Vegetables, fruits, and beans might be a source of chromium exposure. We concluded that skin aging might be positively associated with hair chromium. It is necessary to take measures to reduce chromium exposure to prevent skin aging.

Potentially toxic elements in human scalp hair around China's largest polymetallic rare earth ore mining and smelting area.

There is a growing concern about human health of residents living in areas where mining and smelting occur. In order to understand the exposure to the potentially toxic elements (PTEs), we here identify and examine the cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in scalp hair of residents living in the mining area (Bayan Obo, n = 76), smelting area (Baotou, n = 57) and a reference area (Hohhot, n = 61). In total, 194 hair samples were collected from the volunteers (men = 87, women = 107) aged 5-77 years old in the three areas. Comparing median PTEs levels between the young and adults, Ni levels were significantly higher in adults living in the smelting area while Cr was highest in adults from the mining area, no significant difference was found for any of the elements in the reference area. From the linear regression model, no significant relationship between PTEs concentration, log10(PTEs), and age was found. The concentrations of Ni, Cd, and Pb in hair were significantly lower in the reference area when compared to both mining and smelting areas. In addition, Cu was significantly higher in the mining area when compared to the smelting area. Factor analysis (FA) indicated that men and women from the smelting area (Baotou) and mining area (Bayan Obo), respectively, had different underlying communality of log10(PTEs), suggesting different sources of these PTEs. Multiple factor analysis quantilized the importance of gender and location when combined with PTEs levels in human hair. The results of this study indicate that people living in mining and/or smelting areas have significantly higher PTEs (Cu, Ni, Cd, and Pb) hair levels compared to reference areas, which may cause adverse health effects. Remediation should therefore be implemented to improve the health of local residents in the mining and smelting areas.

Nanocellulose/carbon dots hydrogel as superior intensifier of ZnO/AgBr nanocomposite with adsorption and photocatalysis synergy for Cr(VI) removal.

A novel nanocellulose/carbon dots hydrogel (NCH) was fabricated using cellulose nanofibrils (CN), carbon dots (CD) and zinc oxide (ZnO)/silver bromide (AgBr) nanocomposite, where CD enhanced amino group-induced adsorption of hexavalent chromium (Cr(VI)) and promoted the photocatalytic properties of ZnO/AgBr nanocomposite via the transfer of photogenerated electrons, resulting in enhanced efficiency in the removal of Cr(VI) from aqueous solution. The structure, morphology, and physicochemical properties of the prepared NCH were characterized, with the results of adsorption and photocatalysis experiments showing the maximum theoretical adsorption capacity of the NCH to be 315 mg/g, 219 times that of the ZnO/AgBr nanocomposite; the apparent removal rate constant of the NCH was 0.0319 min-1, 11.7 times that of the ZnO/AgBr nanocomposite. Furthermore, the removal performance of NCH was attributed to CD-enhanced synergistic adsorption and photocatalysis effects, supported by characterization and experimental results. This work provides insight into the design and fabrication of a novel adsorptive photocatalyst with CD-enhanced synergistic adsorption and photocatalysis effects for removing Cr(VI) from aqueous solution.

YTHDF2 controls hexavalent chromium-induced mitophagy through modulating Hif1α and Bnip3 decay via the m6A/mRNA pathway in spermatogonial stem cells/progenitors.

Spermatogonial stem cells (SSCs) are the basis of spermatogenesis, and SSC homeostasis is essential for lifelong male fertility. Currently, environmental pollution remains one of the factors affecting human reproductive health. Chromium is a prevalent metal element, and excessive exposure to hexavalent chromium (Cr (VI)) can cause male reproductive disorders. Nevertheless, the toxic effects of Cr (VI) on SSCs and the underlying mechanisms remain incompletely understood. Here, we showed that Cr (VI) exposure triggered mitophagy in mouse SSCs/progenitors in a time-dependent manner. Concurrently, Cr (VI) treatment caused reactive oxygen species (ROS) accumulation and activated the HIF1α-mediated BNIP3 expression to trigger mitophagy. In addition, Cr (VI) exposure significantly decreased the level of m6A modification. Further, we identified that YTHDF2 regulated the stability of Bnip3 and Hif1α mRNAs in an m6A-dependent manner, which was involved in Cr (VI)-induced mitophagy. Collectively, our study not only expands the mechanisms for Cr (VI)-caused male reproductive toxicity, but also provides pharmacological targets for prevention and treatment of Cr (VI)-induced male fertility impairment.

Removal of Hexavalent Chromium in Aqueous Solution by Cellulose Filter Paper Loaded with Nano-Zero-Valent Iron: Performance Investigation and Numerical Modeling.

Cr(VI) pollution in water bodies is very harmful to human health and the environment. Therefore, it is necessary to remove Cr(VI) from water. In this study, the composite (FP-nZVI) was prepared by loading nano-zero-valent iron (nZVI) onto cellulose filter paper (FP) using a liquid-phase reduction method to improve the dispersibility and oxidation resistance of nZVI. In batch experiments, the effects of iron loading of FP-nZVI, initial concentration of Cr(VI), temperature, and pH on Cr(VI) removal were particularly investigated. The maximum removal rate of 98.6% was achieved at 25 °C, pH = 5, initial concentration of Cr(VI) of 20 mg/L, and FeCl3·6H2O solution concentration of 0.8 mol/L. The removal of Cr(VI) by FP-nZVI conformed to a pseudo-second-order kinetic model and Langmuir isotherm model. The mechanism of Cr(VI) removal was a multi-step removal mechanism, involving adsorption, reduction, and coprecipitation. Column experiments investigated the effect of flow rate (1 mL/min, 3 mL/min, and 5 mL/min) on Cr(VI) removal. We found that increasing flow rate slightly decreased the removal rate of Cr(VI). The transport of Cr(VI) in composite porous media was simulated using HYDRUS-1D, and the results show that the two-site model can well simulate the reactive transport of Cr(VI). This study may provide a useful reference for the remediation of groundwater contaminated with Cr(VI) or other similar heavy metals using FP-nZVI.

The pH-sensitve oxygenation of FeS: Mineral transformation and immobilization of Cr(VI).

Iron sulfide (FeS) has been widely used to reduce toxic Cr(VI) into Cr(III) in anoxic aquatic environments, where pH could strongly influence Cr(VI) removal. However, it remains unclear how pH regulates the fate and transformation of FeS under oxic conditions and the immobilization of Cr(VI). The results of this study showed that typical pH conditions of natural aquatic environment significantly affected the mineral transformation of FeS. Under acidic conditions, FeS was principally transformed to goethite, amarantite, and elemental sulfur with minor lepidocrocite through proton-promoted dissolution and oxidation. Instead, under basic conditions, the main products were lepidocrocite and elemental sulfur via surface-mediated oxidation. In typical acidic or basic aquatic environment, the pronounced pathway for the oxygenation of FeS solids may alter their ability to remove Cr(VI). Longer oxygenation impeded Cr(VI) removal at acidic pH, and a decreasing ability to reduce Cr(VI) caused a drop in Cr(VI) removal performance. Cr(VI) removal decreased from 733.16 to 36.82 mg g-1 with the duration of FeS oxygenation increasing to 5760 min at pH 5.0. In contrast, newly generated pyrite from brief oxygenation of FeS improved Cr(VI) reduction at basic pH, followed by a drop in Cr(VI) removal performance due to the impaired reduction capacity with increasing to the complete oxygenation. Cr(VI) removal increased from 669.58 to 804.83 mg g-1 with increasing oxygenation time to 5 min and then decreased to 26.27 mg g-1 after the full oxygenation for 5760 min at pH 9.0. These findings provide insight into the dynamic transformation of FeS in oxic aquatic environments with various pHs and the impact on Cr(VI) immobilization.

The importance of in-year seasonal fluctuations for biomonitoring of apex predators: A case study of 14 essential and non-essential elements in the liver of the common buzzard (Buteobuteo) in the United Kingdom.

Trace elements are chemical contaminants spread in the environment by anthropogenic activities and threaten wildlife and human health. Many studies have investigated this contamination in apex raptors as sentinel birds. However, there is limited data for long-term biomonitoring of multiple trace elements in raptors. In the present study, we measured the concentrations of 14 essential and non-essential trace elements in the livers of the common buzzard (Buteo buteo) collected in the United Kingdom from 2001 to 2019 and investigated whether concentrations have changed during this period. In addition, we estimated the importance of selected variables for modelling element accumulations in tissues. Except for cadmium, hepatic concentrations of harmful elements in most buzzards were lower than the biological significance level of each element. Hepatic concentrations of certain elements, including lead, cadmium, and arsenic, varied markedly seasonally within years. Their peak was in late winter and trough in late summer, except copper which showed an opposite seasonal pattern. In addition, lead in the liver consistently increased over time, whereas strontium showed a decreasing trend. Hepatic concentrations of cadmium, mercury, and chromium increased with age, whereas selenium and chromium were influenced by sex. Hepatic concentrations of arsenic and chromium also differed between different regions. Overall, our samples showed a low risk of harmful effects of most elements compared to the thresholds reported in the literature. Seasonal fluctuation was an important descriptor of exposure, which might be related to the diet of the buzzard, the ecology of their prey, and human activities such as the use of lead shot for hunting. However, elucidating reasons for these observed trends needs further examination, and biomonitoring studies exploring the effects of variables such as age, sex, and seasonality are required.

Copper modified cobalt-chromium particles for attenuating wear particle induced-inflammation and osteoclastogenesis.

The nature of aseptic prosthetic loosening mainly relates to the wear particles that induce inflammation and subsequent osteoclastogenesis. The ideal approach to impede wear particle-induced osteolysis should minimize inflammation and osteoclastogenesis. In this work, Co29Cr9W3Cu particles were used as a research model for the first time to explore the response of Co29Cr9W3Cu particles to inflammatory response and osteoclast activation in vitro and in vivo by using Co29Cr9W particles as the control group. In vitro studies showed that the Co29Cr9W3Cu particles could promote the generation of M2-phenotype macrophages and increase the expression level of anti-inflammatory factor IL-10, while inhibiting the formation of M1-phenotype macrophages and down-regulating the expression of inflammatory factors TNF-α, IL-6 and IL-1ß; More importantly, the Co29Cr9W3Cu particles reduced the expression of NF-κB and downstream osteoclast related-specific transcription marker genes, such as TRAP, NFATc1, and Cath-K; In vivo results indicated that the Co29Cr9W3Cu particles exposed to murine calvarial contributed to decreasing the amount of osteoclast and osteolysis area. These findings collectively demonstrated that Cu-bearing cobalt-chromium alloy may potentially delay the development of aseptic prosthetic loosening induced by wear particles, which is expected to provide evidence of Co29Cr9W3Cu alloy as an alternative material of joint implants with anti-wear associated osteolysis.

Chromium hydroxide nanoparticles-based fluorescent aptameric sensing for sensitive patulin detection: The significance of nanocrystal and morphology modulation.

The widespread of patulin (PAT) and its potential hazards to human health call for alternative rapid assays to monitor it in food and the environment. Herein, we prepared chromium hydroxide [Cr(OH)3] nanoparticles via a one-pot chemical precipitation strategy and used them to fabricate a turn-on fluorescent aptasensor employing a morphological effect for sensitive PAT detection. Three Cr(OH)3 nanoparticle structures were synthesized by changing the solvent, and their structures and physicochemical properties were investigated. Then, we evaluated the effects of morphological structures on the fluorescence quenching-recovery capability of Cr(OH)3 nanoparticles before and after incubation with PAT. We found that the Cr(OH)3-3 nanoparticles efficiently absorbed the fluorescence dye 6-carboxyfluorescein labeled aptamer (FAM-Apt) and quenched the fluorophore through photoinduced electron transfer. Under optimal experimental conditions, the turn-on fluorescent aptasensor for PAT determination displayed two linear ranges (0.01-10 ng/mL and 1-200 ng/mL) with a low detection limit of 7.3 pg/mL. Moreover, the proposed aptasensor had no cross-reactivity with interferents that usually coexist with PAT and can be used to detect PAT in apple juices accurately. The results of the as-fabricated method were not significantly different from the high-performance liquid chromatography. Hence, we demonstrated that different Cr(OH)3 nanoparticles can be prepared by changing reaction conditions, and provided a novel strategy to improve the detection performance of fluorescent aptasensor by changing the morphological structure and crystalline properties of nano-quenchers.