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Within the scope of this study, a simple, highly sensitive and rapid trapping method for the determination of mercury (Hg) was developed. In this method, the surface of the tungsten coil (W-coil) was coated with platinum using the electrolytic deposition technique. Scanning electron microscopy–energy-dispersive X-ray analyses were performed to examine the surface morphology of Pt-coated W-coil. During the experiment, firstly, Hg vapour generated by tetrahydroborate, used as a reducing agent, was efficiently trapped on the Pt-coated W-coil at collection temperature in hydrochloric acid medium. Subsequently, Hg trapped on the surface of the Pt-coated W-coil was revolatilised by the effect of releasing-stage gases at the optimised releasing temperatures and transported to quartz T-tube atomiser. The experimental conditions have been optimised. Under the optimised conditions, a limit of detection (LOD) of 8.8 ng L−1 was obtained using three times the standard deviation of blank values using Pt-coated W-coil trap cold vapour atomic absorption spectrometry (CVAAS) system. The precision of the measurements was evaluated by relative standard deviation of 4.4%, which is obtained by 11 consecutive measurements of reagent blanks for a collection volume of 6.83 mL corresponding to 90 s collection. The enhancement factors for both LOD (3 s) and characteristic concentration (Co) were found to be 5.09 and 5.02 when compared with the regular CVAAS system without trap. The accuracy of the proposed method was evaluated by analysing BCR 146 R (Sewage sludge), RTC (Sandy Loam 7), ERM-BD151 (skimmed milk powder) and NIST 1641e (mercury in water) certified reference materials (CRMs). There was a good agreement between certified and found values for all CRMs. The results of the application of the developed method in seawater showed the spike recovery ranges from 94.2% to 102.4%. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is detrimental to human health, but its impact on lipid biomarkers remains a subject of controversy. This study sought to delineate a clear link between blood Hg and lipid biomarkers correlated with cardiovascular disease (CVD), including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG), in hypertensive adults in the USA. Methods: This cross-sectional research gathered data from a total of 4415 participants sourced from the National Health and Nutrition Examination Survey (NHANES). The Holm-Bonferroni stepdown procedure was utilized to control the type I error rate in multiple comparisons. We employed multivariable linear regression models to assess the correlation between blood Hg and lipid biomarkers. Subsequently, subgroup analyses were conducted, categorized by both gender and race. Additionally, we used smooth curve fittings and generalized additive models to confirm the presence of non-linear relationships. When non-linearity was detected, we applied a recursive algorithm to calculate the inflection points. Finally, we established a weighted two-piecewise linear regression model to illustrate the associations on either side of the inflection point. Results: In our multivariable linear regression models, clear associations emerged. Specifically, positive correlations were observed between blood mercury and TC (β = 0.025; 95% CI 0.009 to 0.041; corrected P = 0.011), LDL-C (β = 0.022; 95% CI 0.007 to 0.036; corrected P = 0.012), and HDL-C (β = 0.007; 95% CI 0.001 to 0.013; corrected P = 0.058). However, there was no significant correlation with TG (β = − 0.007; 95% CI − 0.018 to 0.004; corrected P = 0.526). Notably, it has been demonstrated that distinct inverted U-shaped and U-shaped curves exist when stratified by gender in our analysis. Conclusions: Blood Hg exhibited a positive correlation with TC, LDL-C, and HDL-C in hypertensive adults in the USA. Nonetheless, no significant association was observed with TG. [ABSTRACT FROM AUTHOR]

Methylmercury (MeHg) and 2,3,7,8-tetrachlorodibenzodioxin (TCDD) are potent environmental pollutants implicated in the modulation of xenobiotic-metabolizing enzymes, particularly the cytochrome P450 1 family (CYP1) which is regulated by the aryl hydrocarbon receptor (AHR). However, the co-exposure to MeHg and TCDD raises concerns about their potential combined effects, necessitating thorough investigation. The primary objective of this study was to investigate the individual and combined effects of MeHg and TCDD on AHR-regulated CYP1 enzymes in mouse extrahepatic tissues. Therefore, C57BL/6 mice were administrated with MeHg (2.5 mg/kg) in the absence and presence of TCDD (15 μg/kg) for 6 and 24 h. The AHR-regulated CYP1 mRNA and protein expression levels were measured in the heart, lung, and kidney, using RT real-time PCR and western blot, respectively. Interestingly, treatment with MeHg exhibited mainly inhibitory effect, particularly, it decreased the basal level of Cyp1a1 and Cyp1a2 mRNA and protein, and that was more evident at the 24 h time point in kidney followed by heart. Similarly, when mice were co-exposed, MeHg was able to reduce the TCDD-induced Cyp1a1 and Cyp1a2 expression, however, MeHg potentiated kidney Cyp1b1 mRNA expression, opposing the observed change on its protein level. Also, MeHg induced antioxidant NAD(P)H:quinone oxidoreductase (NQO1) mRNA and protein in kidney, while heme-oxygenase (HO-1) mRNA was up-regulated in heart and kidney. In conclusion, this study reveals intricate interplay between MeHg and TCDD on AHR-regulated CYP1 enzymes, with interesting inhibitory effects observed that might be significant for procarcinogen metabolism. Varied responses across tissues highlight the potential implications for environmental health. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a persistent soil pollutant, and its toxicity can be evaluated using soil enzyme indicators. However, a thorough understanding of how the enzyme resists and remains resilient to Hg stress is essential, as it significantly impacts the accuracy of toxicity assessments. Therefore, it is worthwhile to understand the functional stability of urease in soil under Hg pollution. This study compares the effects of Hg at different concentrations and exposure times on soil urease. Results indicate that soil urease activity was enhanced in the first two hours under low levels of Hg pollution, decreased after six hours of acute Hg pollution, and reached its maximum reduction in 24 hours. The urease in fluvo-aquic soil, with higher soil organic matter showed higher resistance to Hg acute pollution than that in red soil. Over a longer aging process, soil urease activity gradually recovered with time. Hormesis effects were observed in red soil under high Hg stress after 30 days, showing the strong resilience of urease enzyme function to Hg pollution. The ecological dose, ED10, (the Hg concentration causing a 10% reduction in soil urease activity) ranged from 0.09 to 0.59 mg kg−1 under short-term exposure, and was lower than that under a longer aging process (0.28 to 2.71 mg kg−1). Further, aging reduced the Hg ecotoxicity due to decreased Hg availability and the resilience of soil urease activity. This indicates that the risk of Hg pollution estimated by soil urease as an indicator depends on exposure time and enzyme stability. These factors need consideration in heavy metal pollution assessments using soil enzymes. Highlights: Duration of contamination influences the Hg toxicity to soil urease. Short-time exposure to low-level Hg stress exhibited hormesis effect on soil urease. Soil urease resilience potential to Hg pollution depends on soil type. Soil urease shows strong resilience during the aging process in the presence of Hg. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to evaluate the bound fractions of mercury (Hg), physicochemical parameters, and mineral composition of coal. Coal samples were collected from various depths within Block-VII of the Thar coalfield in Pakistan. The Hg associated with different chemical fractions of coal was extracted using a sequential extraction scheme as per the community bureau of reference (BCR) protocol. This study utilized both the BCR-sequential extraction method (BCR-SEM) and a single-step sequential extraction based on an ultrasonic-assisted method (SSE-UAM) for the fractionation analysis of Hg in coal. The extraction methodologies, BCR-SEM and SSE-UAM, were specifically designed for analyzing Hg fractionation in coal samples. The SSE-UAM offers an operational advantage, requiring only 2 h compared to the 51 h needed for BCR-SEM. The analyses were validated using standard reference material (SRM-1635a) and the spiking addition method, achieving a recovery percentage of 97.1% for total Hg concentrations using the pseudo-extraction method in SRM-1635A. Total Hg content in the coal samples ranged from 0.60 to 2.34 µg g−1 across four different coal seams from Block-VII of the Thar coalfield. Additionally, Hg concentration was observed to decrease with increasing depth, attributed to changes in mineralogical composition. The highest concentration of Hg was detected at a depth of 200–203 m, while the lowest concentration was at a depth of 152–154 m. The concentration of Hg in various fractions was 32–60% in the acid-soluble fraction, 1.72–4.92% in the reducible fraction, and 9.58–50.8% in the oxidizable fractions. The coal sample characteristics were analyzed using an elemental analyzer and scanning electron microscopy with energy-dispersive spectroscopy. Cold vapor atomic absorption spectrometry (CV-AAS) was used to measure the extracted fractional concentration of Hg in coal. [ABSTRACT FROM AUTHOR]

Estuarine sediments serve as significant reservoirs for mercury (Hg) and methylmercury(MeHg), which can also interconvert in the external environment. The release of Hg in response to human activities raises concerns about its potential ecological and human health effects. Sediment samples were collected in December 2021 from four locations (sites), and Hg cycling by measuring the concentrations of, and controls on, the spatial distribution of total Hg (THg) and methylmercury (MeHg) in high-tidal zone (HTZ) and mid-tidal zone (MTZ) sediments of a mangrove forest (MF) and oyster farm (OF) was examined in northwestern Zhanjiang Bay, including simultaneous determination of sediment particle size, oxidation-reduction potential (Eh), pH, total organic carbon (TOC), sulfide concentration (S2-), and sulfate reducing bacteria (SRB). The research results indicated that concentrations of both THg and MeHg ranged between 20.0–104.0 ng/g and 0.011–0.277 ng/g in the sediments, respectively. The highest methylation potentials within the MF and OF were in sediments located approximately 10–15 cm below the surface. MeHg in the HTZ of the OF was likely derived from exogenous inputs as Hg methylation appears limited, and the formation of MeHg depended not only on the amount of inorganic mercury available for methylation in SRB, but also on the TOC, pH, Eh and S2- content in the sediment. A risk assessment of MeHg during the anthropogenic disturbance of this estuaries conducted on individuals eating oysters demonstrated that health risks are low. [ABSTRACT FROM AUTHOR]

Geothermal activity is a natural source of mercury (Hg) to surface environments, but its contributions as part of the larger geogenic flux to the global Hg budget are poorly understood, in part due to large geographic gaps in emissions data where no measurements have been made. In this study we report the results of a field campaign over 2021 and 2022 on the highly active volcanic island country of Iceland. Six geothermal sites across the country were investigated for soil gaseous elemental mercury (GEM) and total Hg (THg) concentrations through a series of measurements made across the diffuse degassing surface. At 10 cm depth, soil GEM concentrations were often hundreds and in some cases thousands of times higher than ambient surface air concentrations. Geothermal soils were also highly enriched in THg due to the sorption of hydrothermal Hg on the characteristically fine, thermally-altered clays and silts. Soil "hotspots" displayed THg concentrations exceeding 100 µg g−1 comparable to levels in areas heavily contaminated by anthropogenic activity and in Hg-rich mineral soils. Strong correlations were observed between soil GEM, THg and soil temperature, and intensive measurements made at small spatial scales (∼1 m2) demonstrated the representativeness of individual sampling points. By adapting an active sampling gradient method for determining soil–air gas fluxes, we estimate an Icelandic geothermal GEM flux of 1.8 kg a−1 and a total Icelandic GEM flux, including non-geothermal areas, of ∼18 kg a−1. This work shows that Icelandic geothermal activity can generate high GEM and THg concentrations in the local soil environment, but its contribution to global Hg cycling appears to be minor. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction: Attention-Deficit/Hyperactivity Disorder (ADHD) is a recognized neurodevelopmental disorder with a complex, multifactorial origin. Lead (Pb) and mercury (Hg) are highly toxic substances that can potentially impair brain development and have been implicated in the development of ADHD. This systematic review aims to analyze the epidemiological literature regarding the association between Pb and Hg exposure and the diagnosis of ADHD. Methods: From November 1983 to June 2, 2023, a comprehensive search was conducted in multiple databases and search engines, including PubMed, Web of Science, Scopus, and Google Scholar. Observational studies (case-control, cohort, and cross-sectional) measuring Pb and Hg levels in various biological samples (blood, hair, urine, nail, saliva, teeth, and bone) of children with ADHD or their parents and their association with ADHD symptoms were included. Results: Out of 2059 studies, 87 met the inclusion criteria and were included in this systematic review. Approximately two-thirds of the 74 studies investigating Pb levels in different biological samples reported associations with at least one subtype of ADHD. However, most studies examining Hg levels in various biological samples found no significant association with any ADHD subtype, although there were variations in exposure periods and diagnostic criteria. Conclusion: The evidence gathered from the included studies supports an association between Pb exposure and the diagnosis of ADHD, while no significant association was found with Hg exposure. Importantly, even low levels of Pb were found to elevate the risk of ADHD. Further research is needed to explore the comprehensive range of risk factors for ADHD in children, considering its significance as a neurodevelopmental disorder. [ABSTRACT FROM AUTHOR]

Background: Diabetic cataract (DC) is a common complication of diabetes and its etiology and progression are multi-factorial. In this study, the roles of specific protein 1 (SP1) and fibroblast growth factor 7 (FGF7) in DC development were explored. Methods: DC cell model was established by treating SRA01/04 cells with high glucose (HG). MTT assay was conducted to evaluate cell viability. Transwell assay and wound-healing assay were performed to assess cell migration and invasion. Western blot assay and qRT-PCR assay were conducted to measure the expression of N-cadherin, E-cadherin, Collagen I, Fibronectin, SP1 and FGF7 expression. CHIP assay and dual-luciferase reporter assay were conducted to analyze the combination between FGF7 and SP1. Results: FGF7 was upregulated in DC patients and HG-induced SRA01/04 cells. HG treatment promoted SRA01/04 cell viability, migration, invasion and epithelial-mesenchymal transition (EMT), while FGF7 knockdown abated the effects. Transcription factor SP1 activated the transcription level of FGF7 and SP1 overexpression aggravated HG-induced SRA01/04 cell injury. SP1 silencing repressed HG-induced SRA01/04 cell viability, migration, invasion and EMT, but these effects were ameliorated by upregulating FGF7. Additionally, SP1 knockdown inhibited the PI3K/AKT pathway by regulating the transcription level of FGF7. Conclusion: Transcription factor SP1 activated the transcription level of FGF7 and the PI3K/AKT pathway to regulate HG-induced SRA01/04 cell viability, migration, invasion and EMT. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a ubiquitous contaminant in wetlands that can cause immunosuppression in birds, which may increase susceptibility to colonization with Salmonella spp. Previously, we found that White Ibis (Eudocimus albus), a recently urbanized wading bird, shed Salmonella spp. at a higher prevalence when captured at urban sites, compared with natural sites. In this study, we sought to determine if Hg burdens in ibis are related to Salmonella status or degree of urbanization or both. We analyzed feathers from 94 ibis in Palm Beach County, Florida, USA, along an urbanization gradient (0-68% urbanization) and from individuals with confirmed Salmonella spp. status (shedding or not shedding). We detected Hg in all ibis feathers (0.22-8.47 mg/kg; mean = 1.96 mg/kg; SD = 1.94). The Hg concentration was not significantly correlated to Salmonella spp. shedding status (Wilcoxon rank sum test, W = 1170; P = 0.596) but was negatively associated with capture site urbanization level (R² = 0.327; P = 0.026). Our findings may suggest that the immunosuppressive effects of Hg do not affect Salmonella shedding in the ibis or that Hg burdens were too low to affect Salmonella shedding status. Further, ibis that were captured in high urbanization sites appeared to have a lower risk of Hg exposure than ibis that were captured within low urbanization sites. [ABSTRACT FROM AUTHOR]

Southern sea otters (Enhydra lutris nereis) are a federally listed threatened keystone species of the California kelp forest ecosystem and a sentinel species, indicating environmental health. Mercury (Hg) is a bioaccumulative neurotoxin that poses a threat to high trophic‐level species such as marine mammals. We quantified total Hg (THg) concentrations in fur, brain, and liver tissues of necropsied southern sea otters (n = 44) that stranded along the California coast from 2010 to 2019. THg concentrations differed significantly between fur and brain, and between liver and brain. Tissue type explained 64%, and sex explained only 3.3% of overall THg variability (0.48–46.1 μg/g dry weight). All individuals had liver Hg concentrations measuring well under the proposed lower‐limit low risk guideline for harp seals, Pagophilus groenlandicus. However, six sea otters exceeded the liver THg moderate risk threshold for terrestrial furbearers to which sea otters are closely related. These data represent baseline THg concentrations in fur, brain, and liver of the southern sea otter and build upon previous studies in various sea otter subspecies. Research on sea otter Hg tolerance and continued monitoring are needed to clarify potential health risks associated with the tissue concentrations observed in this study. [ABSTRACT FROM AUTHOR]

The aim of the research was to investigate the resistance and efficacy of the fungi Aspergillus awamori in removing heavy metals. We conducted an analysis of the fungus's tolerance to several heavy metals by measuring the dry weight and using a plate method. The fungus exhibited growth in concentrations and lowest growth was observed in a concentration of 400 ppm of Cd. The heavy metals were successfully removed with the following orders: Zn> Co, > Ag, > Hg and Cu. The optimal parameters for the elimination of 100 mg/L of heavy metals were a temperature of 28°C, a pH range of 4.0 to 5.5, a heavy metal concentration of 100 ppm, and a biomass of fungi of 1 g. [ABSTRACT FROM AUTHOR]

Introduction: The Brazilian Amazon has one of the richest biomes and the largest source of freshwater on the planet. However, anthropogenic activities have also turned this region into one of the highest points of human exposure to mercury ever recorded. Therefore, the aim of the present work was to perform a scope review with meta-analysis in order to evaluate the total mercury (THg) and methylmercury (MeHg) levels in Brazilian Amazon fish, as well as to carry out a local population health risk assessment. Methods: A literature search was systematically performed in research databases and gray literature, remaining 14 studies from 2017 to 2022 for final analysis. The studies were submitted to raw mean and subgroup meta-analysis, followed by a risk characterization and the calculation of a maximum safe consumption of fish for the Amazonian population. Results: The selected studies covered 4 Amazonian states, as well as included the analysis of >30 fish species of different trophic levels and sampling in >15 cities. The overall total mercury mean obtained for Brazilian Amazon fish was 0.29 ug g⁻¹. Significant difference was observed between THg levels according to fish trophic level (p < 0.05), which reinforces the MeHg biomagnification. When THg levels from all fish samples were pooled, it was not observed a significant difference among the Amazonian states and the fish sampling season. However, significant variations between microregions and species-specific variations over the seasons should not be discarded. All estimated daily methylmercury intake exceeded the reference dose of 0.1 ug kg BW⁻¹ day⁻¹, resulting in a hazard quotient (HQ) greater than 1 and indicating a risk of chronic exposure by the local population. The maximum safe consumption of fish calculated based on the overall total mercury mean was set as 31, 147 and 173 g week⁻¹ for children, adult women and adult men, respectively, which is much lower than the reality of consumption by the riverside communities (2870 g week⁻¹). Conclusion: There is an urgent need to reduce Hg exposure levels in the region as well as to recommend other protective nutritional strategies to the local population such as defining the fish species with lower mercury contamination levels and their safe weekly consumption.

Abstract Fe–Mn oxide modified biochar (FMBC) was produced to explore its potential for remediation of Hg–Cd contaminated paddy soils. The results showed that the application of FMBC decreased the contents of bioavailable Hg and Cd by 41.49–81.85% and 19.47–33.02% in contrast to CK, while the amount of labile organic carbon (C) fractions and C-pool management index (CPMI) was increased under BC and FMBC treated soils, indicating the enhancement of soil C storage and nutrient cycling function. Dry weight of different parts of Oryza sativa L. was enhanced after the addition of BC and FMBC, and the contents of Fe and Mn in root iron–manganese plaques (IMP) were 1.46–2.06 and 6.72–19.35 times higher than those of the control groups. Hg and Cd contents in brown rice under the FMBC treatments were significantly reduced by 18.32–71.16% and 59.52–72.11% compared with the control. FMBC addition altered the composition and metabolism function of soil bacterial communities, especially increasing the abundance of keystone phyla, including Firmicutes, Proteobacteria and Actinobacteria. Partial least squares path modelling (PLSPM) revealed that the contents of Na2S2O3–Hg, DTPA–Cd and IMP were the key indicators affecting Hg and Cd accumulation in rice grains. These results demonstrate the simultaneous value of FMBC in remediation of Hg and Cd combined pollution and restoring soil fertility and biological productivity. Graphical Abstract

Wild boars, being a common game species, inhabit regions across Eurasia, the southern regions of Asia and certain Indonesian islands. Being omnivorous and due to their relatively long lifespan, wide distribution and a relatively high number of shot animals per annual legal hunting season, they are suitable to be biological indicators of occurrence of heavy metals. Concentrations of cadmium, lead, arsenic and mercury were analyzed by atomic absorption spectrometry and cold vapor atomic absorption spectrometry in the livers of free-living wild boars (n = 58) from two locations in the Republic of North Macedonia. In all four examined heavy metals, no statistically significant difference between the locations was found (p > 0.05). The mean levels of heavy metals were Cd 0.391 mg/kg and 0.339 mg/kg; Pb 0.213 mg/kg and 0.204 mg/kg; Hg 0.034 mg/kg and 0.037 mg/kg; As 0.035 mg/kg and 0.029 mg/kg in the livers of boars from Bitola and Gevgelija hunting sites, respectively. Although some samples (two samples of Hg, ten samples of Cd and two samples of Pb) exceeded the legal limits, the average values for all heavy metals were far below the maximum permitted values. These findings are promising since they suggest that the ecosystem in the Republic of North Macedonia is stable concerning heavy metal pollution.

Fe–Mn oxide modified biochar (FMBC) was produced to explore its potential for remediation of Hg–Cd contaminated paddy soils. The results showed that the application of FMBC decreased the contents of bioavailable Hg and Cd by 41.49–81.85% and 19.47–33.02% in contrast to CK, while the amount of labile organic carbon (C) fractions and C-pool management index (CPMI) was increased under BC and FMBC treated soils, indicating the enhancement of soil C storage and nutrient cycling function. Dry weight of different parts of Oryza sativa L. was enhanced after the addition of BC and FMBC, and the contents of Fe and Mn in root iron–manganese plaques (IMP) were 1.46–2.06 and 6.72–19.35 times higher than those of the control groups. Hg and Cd contents in brown rice under the FMBC treatments were significantly reduced by 18.32–71.16% and 59.52–72.11% compared with the control. FMBC addition altered the composition and metabolism function of soil bacterial communities, especially increasing the abundance of keystone phyla, including Firmicutes, Proteobacteria and Actinobacteria. Partial least squares path modelling (PLSPM) revealed that the contents of Na2S2O3–Hg, DTPA–Cd and IMP were the key indicators affecting Hg and Cd accumulation in rice grains. These results demonstrate the simultaneous value of FMBC in remediation of Hg and Cd combined pollution and restoring soil fertility and biological productivity. Highlights: FMBC effectively remediated Hg and Cd co-contaminated paddy soils. FMBC increased soil labile C fractions and C sequestration. FMBC improved the relative abundance of specific phyla and metabolism potential. PLSPM exhibited the main ways of reducing Hg and Cd accumulation in rice grains. [ABSTRACT FROM AUTHOR]

The levels of mercury (Hg) were examined in the leg muscle of the crab Grapsus grapsus from five sites on four islands within the Galápagos archipelago. Mercury values obtained using a Milestone DMA 80 evo direct mercury analyzer varied both within and among sites. Total mercury concentrations (mg kg−1 dry weight) ranged from the lowest at a protected location at Isabela Island (0.06 ± 0.02) to the highest at the San Cristóbal urban location (2.04 ± 0.069). Crabs from South Plaza Island also had surprisingly high levels of mercury with a mean of 1.2 ± 0.6. Values from urban sites at Isabela Island and Academy Bay, Santa Cruz, had intermediate values. When converted to wet weight, crabs from both San Cristóbal and South Plaza were within or above the levels (0.3–0.5 mg kg−1 wet weight set by various government agencies) considered potentially harmful to human health if ingested. A lesser number of both oysters and barnacles were also analyzed for mercury at South Plaza and Academy Bay, and while the values were lower compared to the crabs, they followed the same pattern of elevated levels at South Plaza compared to Academy Bay. It is unclear as to whether the mercury comes from natural sources, such as volcanism, or anthropogenic causes. [ABSTRACT FROM AUTHOR]

Bonnethead and Caribbean sharpnose sharks frequent coastal waters, rendering them vulnerable to overexploitation, with the bonnethead shark listed as endangered by the IUCN. Marine Protected Areas (MPAs) have been suggested as a management strategy to regulate shark-exploitation. Moreover, it's essential to identify key areas where nursery grounds (NG) and adult habitats overlap to prioritize conservation zones within MPAs. Along the Caribbean Sea, several NG have been identified for larger shark species, but little is known for smaller sharks. In Bocas del Toro (BDT-Panamanian Caribbean), both bonnethead and Caribbean sharpnose sharks are distributed, with the former appearing to be genetically isolated. The local MPA in BDT doesn't include a NG identified near Solarte Island. In this study, to provide ecological information on bonnethead and Caribbean sharpnose sharks within this potential NG, we evaluated stable isotopes (δ13C and δ15N) and total-mercury (THg) values in their fins. The results revealed a higher proportion of small-adult sharks in the NG, emphasizing the necessity of conducting a comprehensive study to further characterize this area. Moreover, there was no niche-partitioning between the two species and their diets primarily consisted of small prey-items, as evidenced by the significant and negative relationship between isotopic values. Both species exhibited low THg levels in their fins. Based on these initial results and previous genetic data, it appears that BDT plays a critical role as a habitat for sharks. Thus, extending the local MPA to cover the potential NG could effectively ensure conservation of bonnethead and Caribbean sharpnose sharks in BDT. [ABSTRACT FROM AUTHOR]

[Objective] To determine the content of two harmful heavy metal elements (As and Hg), and establish a detection method for As and Hg in Gardenia jasminoides. [Method] After microwave digestion of the sample, the content of As and Hg was determined by atomic fluorescence spectrometry. [Result] The As content in Gardenia jasminoides was 0.104 5 mg/kg, and the Hg content was 0.014 1 mg/kg, both of which were lower than the national standard and comply with the limit requirements of the 2020 edition of the Chinese Pharmacopoeia. [Conclusion] This method was efficient, accurate, reliable and highly precise, providing a simple and fast testing method for the quality control and monitoring of As and Hg in traditional Chinese medicine. [ABSTRACT FROM AUTHOR]

Reprocessing of mine wastes is a growing procedure around the world, in order to extract more resources from already-mined rocks. Mineralogical and geometallurgical investigations are useful for planned reprocessing, and in this study at Round Hill placer gold mine we characterise fine (<100 µm) and super-fine (micron-scale) particulate gold that has passed through the mine separation stages without being extracted. The gold was discharged with water and suspended sediments to settling ponds, separate from the more voluminous gravel and sand tailings. Authigenic clay and pyrite are abundant in the placer deposit and the settled suspension, and oxidised pyrite yielded gypsum and ferric oxyhydroxide. These minerals coat surfaces of gold particles and are locally intergrown with micron-scale authigenic gold. Most of the gold has toroidal shapes characteristic of beach derivation, and many of these are hollow or clay-filled. Minor super-fine cinnabar and mercury-bearing gold occur with clay. Annealing of gold has liberated silver, and micron-scale authigenic native silver occurs in the settled sediment. Reconcentration of fine and super-fine gold used abundant clean water and slow reprocessing and may be currently uneconomic at this site. The observations on suspended gold loss are relevant to gold recovery at placer mines around the world. [ABSTRACT FROM AUTHOR]

Relevance. The need to study the features of aerogenic effects of the Norilsk industrial complex on the natural environment. Aim. To study the features of the aerogenic effects of the Norilsk industrial complex in the south-southwest zone at a distance of 40–60 km using lichens Cladonia rungeferina and Cetraria sp. Objects. Soil, lichens Cladonia rungeferina and Cetraria sp. Methods. Soil and lichen samples were taken 40–60 km south-southwest of the Norilsk Industrial district. Sampling was carried out according to the scheme of two profiles with a length of 14 and 20 km. The samples were analyzed using a set of methods consisting of X-ray fluorescence (S4 Pioneer Bruker AXS), atomic absorption methods (KVANT-2A, Julia-5K) and induction-coupled plasma mass spectrometry (ELEMENT-2) in the laboratory of the GIN RAS, Moscow. The concentration of Ti, V, Ni, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Rb, Cd, Sb, Ba, La was determined. Results. The authors have obtained the data on the concentration of the 21 elements in soils and lichens. The paper demonstrates the calculation of distribution of elements in soil and lichens relative to the concentration in the upper part of the continental crust. The authors calculated the enrichment factor EF for Mn, Ni, Cu, Hg, Pb and estimated the distribution of this coefficient for both profiles. It is shown that the technogenic component of the aerogenic effect for Mn, Ni, Cu, Pb to the south-southwest of the Norilsk industrial complex at a distance of 40–60 km is practically absent. The increased values of the enrichment factor EF in lichens for Hg are explained by a combination of two factors – the constant presence of mercury in significant concentrations in ecosystems and tundra fires that took place in this zone in 2019–2020, which ultimately led to the re-deposition of Hg in the burnt areas.

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Terrestrial soils in forested landscapes represent some of the largest mercury (Hg) reserves globally. Wildfire can alter the storage and distribution of terrestrial-bound Hg via reemission to the atmosphere or mobilization in watersheds where it may become available for methylation and uptake into food webs. Using data associated with the 2007 Moonlight and Antelope Fires in California, we examined the long-term direct effects of wildfire burn severity on the distribution and magnitude of Hg concentrations in riparian food webs. Additionally, we quantified the cross-ecosystem transfer of Hg from aquatic invertebrate to riparian bird communities; and assessed the influence of biogeochemical, landscape variables, and ecological factors on Hg concentrations in aquatic and terrestrial food webs. Benthic macroinvertebrate methylmercury (MeHg) and riparian bird blood total mercury (THg) concentrations varied by 710- and 760-fold, respectively, and Hg concentrations were highest in predators. We found inconsistent relationships between Hg concentrations across and within taxa and guilds in response to stream chemical parameters and burn severity. Macroinvertebrate scraper MeHg concentrations were influenced by dissolved organic carbon (DOC); however, that relationship was moderated by burn severity (as burn severity increased the effect of DOC declined). Omnivorous bird Hg concentrations declined with increasing burn severity. Overall, taxa more linked to in situ energetic pathways may be more responsive to the biogeochemical processes that influence MeHg cycling. Remarkably, 8 years post-fire, we still observed evidence of burn severity influencing Hg concentrations within riparian food webs, illustrating its overarching role in altering the storage and redistribution of Hg and influencing biogeochemical processes. [ABSTRACT FROM AUTHOR]

A comprehensive investigation of the Hg2+ coordination chemistry and 197m/gHg radiolabeling capabilities of cyclen-based commercial chelators, namely, DOTA and DOTAM (aka TCMC), along with their bifunctional counterparts, p-SCN-Bn- DOTA and p-SCN-Bn-TCMC, was conducted to assess the suitability of these frameworks as bifunctional chelators for the 197m/gHg2+ theranostic pair. Radiolabeling studies revealed that TCMC and DOTA exhibited low radiochemical yields (0%-6%), even when subjected to harsh conditions (80°C) and high ligand concentrations (10-4 M). In contrast, p-SCN-Bn-TCMC and p-SCN-Bn-DOTA demonstrated significantly higher 197m/gHg radiochemical yields (100% ± 0.0% and 70.9% ± 1.1%, respectively) under the same conditions. The [197m/gHg]Hg-p-SCN-Bn-TCMC complex was kinetically inert when challenged against human serum and glutathione. To understand the differences in labeling between the commercial chelators and their bifunctional counterparts, non-radioactive natHg2+ complexes were assessed using NMR spectroscopy and DFT calculations. The NMR spectra of Hg- TCMC and Hg-p-SCN-Bn-TCMC suggested binding of the Hg2+ ion through the cyclen backbone framework. DFT studies indicated that binding of the Hg2+ ion within the backbone forms a thermodynamically stable product. However, competition can form between isothiocyanate binding and binding through the macrocycle, which was experimentally observed. The isothiocyanate bound coordination product was dominant at the radiochemical scale as, in comparison, the macrocycle bound product was seen at the NMR scale, agreeing with the DFT result. Furthermore, a bioconjugate of TCMC (TCMC- PSMA) targeting prostate-specific membrane antigen was synthesized and radiolabeled, resulting in an apparent molar activity of 0.089 MBq/nmol. However, the complex demonstrated significant degradation over 24 h when exposed to human serum and glutathione. Subsequently, cell binding assays were conducted, revealing a K, value ranging from 19.0 to 19.6 nM. This research provides crucial insight into the effectiveness of current commercial chelators in the context of 197m/gHg2+ radiolabeling. It underscores the necessity for the development of specific and customized chelators to these unique "soft" radiometals to advance 197m/gHg2+ radiopharmaceuticals. [ABSTRACT FROM AUTHOR]

The incorporation of Visible Light Communication (VLC) in the military services, different organizations, and homes is prominently seen and it becomes an important area to explore. In VLC systems, optical code division multiplexing (OCDMA) is a prominent multiple access method that provides great security while serving several users. Multicode keying, wavelength conversion, quantum key distribution, and optical logic gates are some of the most often utilised security improving techniques, although they are expensive and complicated. This study introduces the two-dimensional (2D) weight managed Zero Cross Correlation (WMZCC), non-adjacent weights (W) and time (t) dimension based optical code with increased security. Comparison of different Hermite Gaussian (HG) and Laguerre-Gaussian (LG) modes has been performed in 5 user × 100 Gbps OCDMA system over 5 m employing mode division multiplexing (MDM) in 2D-WMZCC codes in terms of Q factor and bit error rate. It is observed that HG modes in proposed 2D-WMZCC codes show more resistance to data eavesdropping than LG modes. [ABSTRACT FROM AUTHOR]

In order to study the distribution characteristics and health risk status of heavy metals in Houttuynia cordata in Zunyi City, the Hg, Se and Zn contents in Houttuynia cordata in the local market were measured. The distribution differences of Hg, Se and Zn in roots and underground stems of Houttuynia cordata were analyzed, and the health risk of residents consuming Hg, Se and Zn through Houttuynia cordata was preliminarily evaluated using the target hazard coefficient (THQ) and total target hazard coefficient (TTHQ). The results showed that the contents of Hg, Se and Zn in roots were 10, 21 and 4 times higher than those in rhizomes, respectively. The levels of Hg and Zn in underground parts of Houttuynia cordata were lower than the national limit values (0.01 and 20 mg/kg). The contents of Se in 16 samples exceeded the national limit values (0.1 mg/kg), accounting for 80% of all samples. The THQ and TTHQ of Hg, Se, and Zn consumed by residents in Zunyi City through consumption of Houttuynia cordata were all less than 1, indicating a lower health risk, with Se being relatively higher. The estimated weekly intake values for Hg and Zn were also less than the provisional tolerable weekly intake value (4,7000 µg/kg). Due to the strong enrichment ability of Houttuynia cordata to both Hg and Se in soil, more attention should be paid to health risk of Hg and Se for residents in Zunyi City. [ABSTRACT FROM AUTHOR]

The southern elephant seal (SES; Mirounga leonina) has a circumpolar distribution, breeding mainly on sub‐Antarctic islands and making long trips between breeding or molting and foraging areas. Most individuals from colonies in the South Shetland Islands (western Antarctic Peninsula; WAP) are distributed in Antarctic Specially Protected Areas (ASPA). Despite these protected habitats, pollutants can reach such remote areas far away from emission sources, affecting local fauna. To assess possible mercury (Hg) contamination in SES, we analyzed skin samples collected from free‐ranging molting individuals using the remote biopsy PAXARMS system in Isla 25 de Mayo/King George Island (62°15′S, 58°39′W; ASPA 132). Hairless skin samples were analyzed to determine total‐Hg (THg) concentrations, which ranged between 145 ng/g and 1,915 ng/g (M = 730, SD = 388 ng/g), showing significant differences between sexes, with adult‐females having higher concentrations (range = 306–1,915, M = 859, SD = 427 ng/g dw) than subadult‐males (range = 145–1,645, M = 629, SD = 329 ng/g dw). These differences may be explained mainly by feeding‐niche partitioning between sexes. Females prefer mesopelagic prey or prey associated with sea‐ice in the WAP, which are enriched in methylmercury. These results provide insight regarding Hg contamination in top Antarctic predators like SES, and the need to monitor for potential effects of Hg contamination in Antarctic marine mammals. [ABSTRACT FROM AUTHOR]

Bonnethead and Caribbean sharpnose sharks frequent coastal waters, rendering them vulnerable to overexploitation, with the bonnethead shark listed as endangered by the IUCN. Marine Protected Areas (MPAs) have been suggested as a management strategy to regulate shark-exploitation. Moreover, it’s essential to identify key areas where nursery grounds (NG) and adult habitats overlap to prioritize conservation zones within MPAs. Along the Caribbean Sea, several NG have been identified for larger shark species, but little is known for smaller sharks. In Bocas del Toro (BDT-Panamanian Caribbean), both bonnethead and Caribbean sharpnose sharks are distributed, with the former appearing to be genetically isolated. The local MPA in BDT doesn't include a NG identified near Solarte Island. In this study, to provide ecological information on bonnethead and Caribbean sharpnose sharks within this potential NG, we evaluated stable isotopes (δ13C and δ15N) and total-mercury (THg) values in their fins. The results revealed a higher proportion of small-adult sharks in the NG, emphasizing the necessity of conducting a comprehensive study to further characterize this area. Moreover, there was no niche-partitioning between the two species and their diets primarily consisted of small prey-items, as evidenced by the significant and negative relationship between isotopic values. Both species exhibited low THg levels in their fins. Based on these initial results and previous genetic data, it appears that BDT plays a critical role as a habitat for sharks. Thus, extending the local MPA to cover the potential NG could effectively ensure conservation of bonnethead and Caribbean sharpnose sharks in BDT.

Diabetic retinopathy (DR), a major complication of diabetes causing blindness, is characterized by retinal damage due to capillary degeneration and vascular leakage. Current treatments are not fully effective, highlighting the need for searching new therapeutic targets. Hematopoietic cell kinase (HCK), a protein involved in various diseases, has been identified as a potential biomarker in DR, but its role in disease progression requires further investigation. Here we investigated the role of HCK in DR and its potential mechanism. We found the expression of HCK increased under the stimulation of high glucose (HG) in human retinal capillary endothelial cells (HRECs). Knockdown of HCK can improve HREC cell viability and the integrity of the internal blood–retinal barrier. HCK depletion suppressed the AMPK pathway in HG-induced HRECs. In summary, HCK may be a potential target for the treatment of DR, which provides a theoretical basis for the development of new treatment strategies.

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.

A comprehensive investigation of the Hg2+ coordination chemistry and 197m/gHg radiolabeling capabilities of cyclen-based commercial chelators, namely, DOTA and DOTAM (aka TCMC), along with their bifunctional counterparts, p-SCN-Bn-DOTA and p-SCN-Bn-TCMC, was conducted to assess the suitability of these frameworks as bifunctional chelators for the 197m/gHg2+ theranostic pair. Radiolabeling studies revealed that TCMC and DOTA exhibited low radiochemical yields (0%–6%), even when subjected to harsh conditions (80°C) and high ligand concentrations (10–4 M). In contrast, p-SCN-Bn-TCMC and p-SCN-Bn-DOTA demonstrated significantly higher 197m/gHg radiochemical yields (100% ± 0.0% and 70.9% ± 1.1%, respectively) under the same conditions. The [197 m/gHg]Hg-p-SCN-Bn-TCMC complex was kinetically inert when challenged against human serum and glutathione. To understand the differences in labeling between the commercial chelators and their bifunctional counterparts, non-radioactive natHg2+ complexes were assessed using NMR spectroscopy and DFT calculations. The NMR spectra of Hg-TCMC and Hg-p-SCN-Bn-TCMC suggested binding of the Hg2+ ion through the cyclen backbone framework. DFT studies indicated that binding of the Hg2+ ion within the backbone forms a thermodynamically stable product. However, competition can form between isothiocyanate binding and binding through the macrocycle, which was experimentally observed. The isothiocyanate bound coordination product was dominant at the radiochemical scale as, in comparison, the macrocycle bound product was seen at the NMR scale, agreeing with the DFT result. Furthermore, a bioconjugate of TCMC (TCMC-PSMA) targeting prostate-specific membrane antigen was synthesized and radiolabeled, resulting in an apparent molar activity of 0.089 MBq/nmol. However, the complex demonstrated significant degradation over 24 h when exposed to human serum and glutathione. Subsequently, cell binding assays were conducted, revealing a Ki value ranging from 19.0 to 19.6 nM. This research provides crucial insight into the effectiveness of current commercial chelators in the context of 197m/gHg2+ radiolabeling. It underscores the necessity for the development of specific and customized chelators to these unique “soft” radiometals to advance 197m/gHg2+ radiopharmaceuticals.

In order to assess the influencing factors of the presence of mercury in a river within the Savanna biome (Cerrado), we surveyed total mercury (THg) in bottom sediment from 50 lakes along 750 km of the Middle Araguaia floodplain. The sampling sites included non-urban and urban surroundings over three distinct geomorphologies. We measured water physicochemical parameters at each site and tested statistically if land use nested within the geological formation influenced the THg concentration in bottom sediments and related water parameters. Multivariate results indicate that the interaction between geological groups and land use is statistically significant (p < 0.05). Nested ANOVA and Tukey HSD tests confirmed that the geological formation with its nested land use influences the THg, pH, DO, conductivity, and TDS (p < 0.05). THg was significantly lower in Quaternary terrains (p < 0.05) and differed significantly between non-urban and urban areas in Neoproterozoic terrains (p = 0.02). The spatial projections of the THg eigenvector on the main axes with the scoring factors of the Neoproterozoic/Paleoproterozoic terrains, and urban/non-urban, confirmed the spatial correlations. These results indicate that the association of land use and geology could be the main driver of THg in the bottom sediments of lakes from the Middle Araguaia floodplain. [ABSTRACT FROM AUTHOR]

Background: Despite the concern over reproductive damage from sodium fluoride exposure, there is limited scientific data on the synergistic effect of Homtamin ginseng and vitamin E. A potential remedy could include Homtamin ginseng and vitamin E supplementation, but further research is needed. This research was conducted to investigate the effects of Homtamin ginseng and vitamin E on the reproductive damage induced by sodium fluoride exposure. Different treatment protocols were employed, such as administering drugs alone, preventive measures, and reversal approaches. Methods: In the drug alone or preventive-protocol, rats received oral treatment of Saline (2 mL/kg), Homtamin ginseng (40 mg/kg/day), vitamin E (150 mg/kg/day) or both alone repeatedly for 28 days, or in combination with sodium fluoride (100 ppm/kg/P.O./day) from days 15-28. In the reversal-protocol, the animals received NaF for 28 days prior to saline, Homtamin ginseng, vitamin E or Homtamin ginseng + vitamin E from days 15-28. Results: The result showed an increase (P < 0.05) in testicular malondialdehyde and a decrease in the activities of testicular superoxide dismutase, catalase and glutathione peroxidase in the group exposed to sodium fluoride. These changes were significantly (P < 0.05) ameliorated by vitamin E and Homtamin ginseng. More so, sodium fluoride altered testicular and brain weight, spermatogenesis, hormonal profile, fertility test as well as testicular architecture negatively following treatment with sodium fluoride. However, Homtamin ginseng and vitamin E or combination of both prevented and reversed the effects of sodium fluoride on spermatogenesis, hormonal profile, fertility, and mating indices in rats. Conclusion: In conclusion, Homtamin ginseng and vitamin E prevented and reversed sodium fluoride-induced testicular dysfunction through inhibition of oxidative influx and hormonal modulation mechanism in Wistar rats. [ABSTRACT FROM AUTHOR]

Cereals and cereal-based foods continue to be basic foods in all diets. Despite being known for their high nutritional value; they can also contain contaminants (hazards) such as toxic metals. This study assesses the Cd, Pb and Hg dietary exposure from cereals and derivatives marketed in Madeira and the Azores and characterizes the risks by evaluating the Cd and Hg intake contributions to the tolerable intakes and by estimating the Margin of Exposure (MOE) in the case of Pb. In Madeira, metals follow the descending order of Cd > Pb > Hg. Cd stands out as having the highest levels (0.307 mg Cd/kg in oats; 0.237 mg/kg in rye). High levels of Pb (0.347 mg/kg) were also detected in rye. Regarding total mercury, rice stands out (0.0013 mg/kg) followed by wheat (0.001 mg/kg). While all cereals and derivatives except maize consumed in Madeira exceed the maximum value of Cd allowed by the EU, 50.0% of the rye and 25.0% of the corn flour samples exceeded the European Pb limit. The daily consumption of 100 g of oats, rye flour and rye represent high contributions to the TWI of Cd (93.2 – 120%). The MOE values of Pb from the consumption of rye (100 g/day) are 1,294 (nephrotoxic effects) and 3,082 (cardiotoxic effects). In the Azores, corn flour (0.72 mg Pb/kg) stands out with 85.7% of the samples exceeding the maximum Pb EU limit and MOE values of 626 (nephrotoxic effects) and 1,490 (cardiotoxic effects). Regular daily consumption of corn flour makes a low (< 10%) contribution to the Cd TDI. In conclusion, the Pb exposure from the consumption of cereals and derivatives could have toxic effects such as nephrotoxicity or cardiotoxicity in adults. The results highlight the need to set up monitoring and surveillance programs for the safety of cereals and their derivatives in Madeira and the Azores in terms of lead and cadmium. [ABSTRACT FROM AUTHOR]

The elements in blood normally reflect the levels in prey, indicating a recent exposure. Laughing gulls (Leucophaes atricilla) eat mainly horseshoe crab eggs (Limulus polyphemus) in the spring in Delaware Bay, New Jersey. The levels of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) in the blood of laughing gulls foraging on crab eggs were examined in Delaware Bay to provide information on a species that is normally a generalist, and to determine if the levels of these elements were similar in 2019 and 2022/2023, were intercorrelated, and were related to those in crab eggs. Hg increased from 2019 (136 ± 31 ng/g) to 2022/2023 (473 ± 75 ng/g), while Cd and Se decreased. There were some significant correlations among elements and a close relationship between the element levels in blood and those in crab eggs collected in the same month (except for As). The levels differed between laughing gulls and three species of shorebirds for As and Cd. The elements in the blood of gulls and shorebirds should be similar because they eat mainly the same eggs in the same places. A significant proportion of laughing gull blood samples had levels of Hg and Se that were above the levels associated with adverse effects, which requires further examination. [ABSTRACT FROM AUTHOR]

Bivalves Mollusks have a potential benefit which include protection from anemia due to its content of iron and vit B12 in addition they pose a threat in promoting the ability to be contaminated by different heavy metals residues as a result of mining, industrial production untreated sewage sludge. Hg, Pb, Cd, As and Cr are the main five toxic heavy metals that induce human poisoning. For evaluation of Hg, Pb, Cd, As and Cr residues in Bivalve Mollusks in Fayoum province and their potential hazards, a total of 64 random samples of Bivalve Mollusks (Callista Florida species) were collected from the fish markets of Fayoum City, (Wadi Elrayan), Egypt The results revealed that the mean residues of Hg, Pb, Cd, As and Cr were 0.75, 0.77, 0.089, 7.285 and 0.011 mg/kg/ww, respectively. All samples examined for Hg and As exceeded the PML while Pb and Cd lied with the PML The collected samples were subjected to soaking in running water for 30 minutes; soaking in 5% acetic acid solution for 30 minutes and boiling with 5% acetic acid solution for 15 minutes .The heights reduction % of heavy metals residual levels were recorded after treatment in boiling 5% acetic acid treatment with the following reduction %; Hg (80%), Pb (67.6%), Cd (77.5%), As (44.35%) and Cr (75.76%). The assessment of Hazard quotient (HQ) and hazard index (HI) value was exceeded 1 which indicates a potential risk to human health and TR was > 1x10-4 which indicates a carcinogenic risk to the local consumers and will face high chronic risk if they consume Bivalve Mollusks on regular basis in their diet. [ABSTRACT FROM AUTHOR]

The present study investigated the bioaccumulation and translocation of mercury (Hg) and chromium (Cr) in Yunyan 87 flue-cured tobacco (Nicotiana tabacum) and assessed the influence of soil pH on the metal uptake by plant organs at the field scale. The study was conducted in 4 different regions selected from Sichuan Province, China: Guangyuan, Luzhou, Panzhihua, and Yibin. The results revealed that Hg highly contaminated Yibin soils at 0.29 mg kg−1 and by Cr at 147 mg kg-1, which is above the permissible limit. The levels of Hg in tobacco plant organs were predominantly in the order of leaves > root > stem. The overall trend for Cr contents in tobacco organs was in the order of root > leaves > stem. The results of an index of bioaccumulation (IBA) and translocation factor (TF) showed that the values observed in Panzhihua and Guangyuan tobacco leaves were generally higher, despite the low levels of soil contamination. The linear mixed model (LMM) demonstrated that the log of Hg IBA in tobacco organs was likely to decrease with soil pH increase, whereas the log of Cr IBA only decreased in the root but gradually increased in the aerial parts with soil pH increase. The total random variation in the log of metals' IBA due to regions indicated that for Hg, 33.42% of the variation was explained by regional differences, while for Cr, only 13% was accounted. The results suggested that Yibin and Luzhou need to correct the soil acidity if they are set to reduce Hg contamination in tobacco-growing soils. Guangyuan and Panzhihua need efforts to keep the soil pH on track to avoid high contamination levels, and effective measures of soil nutrients supply are required to produce high tobacco leaf quality free from heavy metal content. The findings of this study may be used to ascertain regional differences in heavy metals, particularly Hg and Cr uptake by tobacco plant organs, and to prevent the cultivation areas contamination through soil pH monitoring. [ABSTRACT FROM AUTHOR]

Due to its persistence and potential ecological and health impacts, mercury (Hg) is a global pollutant of major concern that may reach high concentrations even in remote polar oceans. In contrast to the Arctic Ocean, studies documenting Hg contamination in the Southern Ocean are spatially restricted and large-scale monitoring is needed. Here, we present the first circumpolar assessment of Hg contamination in Antarctic marine ecosystems. Specifically, the Adélie penguin (Pygoscelis adeliae) was used as a bioindicator species, to examine regional variation across 24 colonies distributed across the entire Antarctic continent. Mercury was measured on body feathers collected from both adults (n = 485) and chicks (n = 48) between 2005 and 2021. Because penguins' diet represents the dominant source of Hg, feather δ13C and δ15N values were measured as proxies of feeding habitat and trophic position. As expected, chicks had lower Hg concentrations (mean ± SD: 0.22 ± 0.08 μg·g‒1) than adults (0.49 ± 0.23 μg·g‒1), likely because of their shorter bioaccumulation period. In adults, spatial variation in feather Hg concentrations was driven by both trophic ecology and colony location. The highest Hg concentrations were observed in the Ross Sea, possibly because of a higher consumption of fish in the diet compared to other sites (krill-dominated diet). Such large-scale assessments are critical to assess the effectiveness of the Minamata Convention on Mercury. Owing to their circumpolar distribution and their ecological role in Antarctic marine ecosystems, Adélie penguins could be valuable bioindicators for tracking spatial and temporal trends of Hg across Antarctic waters in the future. Highlights: Adélie penguins are relevant bioindicators of Hg contamination in Antarctic marine ecosystems. Feather Hg concentrations were measured in 24 breeding colonies (adults and chicks). The highest Hg concentrations were found in the Ross Sea. Both trophic ecology and colony location drove feather Hg concentrations. [ABSTRACT FROM AUTHOR]

The levels of mercury (Hg) were examined in the leg muscle of the crab Grapsus grapsus from five sites on four islands within the Galápagos archipelago. Mercury values obtained using a Milestone DMA 80 evo direct mercury analyzer varied both within and among sites. Total mercury concentrations (mg kg−1 dry weight) ranged from the lowest at a protected location at Isabela Island (0.06 ± 0.02) to the highest at the San Cristóbal urban location (2.04 ± 0.069). Crabs from South Plaza Island also had surprisingly high levels of mercury with a mean of 1.2 ± 0.6. Values from urban sites at Isabela Island and Academy Bay, Santa Cruz, had intermediate values. When converted to wet weight, crabs from both San Cristóbal and South Plaza were within or above the levels (0.3–0.5 mg kg−1 wet weight set by various government agencies) considered potentially harmful to human health if ingested. A lesser number of both oysters and barnacles were also analyzed for mercury at South Plaza and Academy Bay, and while the values were lower compared to the crabs, they followed the same pattern of elevated levels at South Plaza compared to Academy Bay. It is unclear as to whether the mercury comes from natural sources, such as volcanism, or anthropogenic causes.

Relevance. The need to study contribution of biogenic factors to migration of elements and response of ecological and geochemical system to natural and technogenic situation, which makes it possible to identify the presence of biogeochemical anomalies. Aim. To determine ecological and geochemical features of mercury load in the south of Western Siberia (Tomsk region, Kemerovo region, Altai Territory) according to research (leaves of aspen (Populus tremula L., family Salicaceae)). Objects. Aspen leaves, widely used to analyze the biogeochemical cycle of chemical elements and their migration in the "soil–plant" system, reflect the elemental composition of growing environment and can act as a biogeoindicator for biogeochemical studies. Methods. Sampling of aspen leaves, drying at room temperature, grinding, atomic absorption analysis of mercury on an RA-915M analyzer with the PIRO-915+ attachment (pyrolysis method). The application program STATISTICA 12 was used to process the data analysis and calculate eco-geochemical indicators: concentration factor, enrichment factor, bioaccumulation factor, concentration clarke. Results. The article presents original data on Hg gross concentration in aspen leaves in Tomsk, Kemerovo regions and Altai Territory. The authors have revealed the features of pollutant accumulation depending on the area of growth, geography and orography of the territory, geochemical features of the study areas, and the influence of anthropogenic factors. Calculations of the main geo-environmental indicators of the mercury load were made. The calculation results indicate that the concentrations are higher than the background, the Clarke of the noosphere, and the average for the dry matter of terrestrial plants. The presence of the element in the form available to plants was revealed in the substrate, as evidenced by the results of calculating the bioaccumulation coefficient. Geographically, Hg accumulation in aspen leaves in the south of Western Siberia is associated with the prevailing wind direction and the impact of anthropogenic sources.

This study focuses on implementing a wind turbine emulator based on a permanent magnet synchronous machine with excitation auxiliary windings and thoroughly investigates the space harmonics created by this innovative topology in MATLAB/Simulink. A Hybrid Generator (HG) is a robust generator that does not have slip rings or brushes in its structure. Furthermore, the flux of the hybrid generator HG may be easily adjusted as it is created by direct current excitation coils and permanent magnets. Unfortunately, the space harmonic rate in the HG is relatively high. In other words, the mechanical vibrations caused by the electromagnetic torque ripple threaten the drive train's behaviour and, ultimately, the wind turbine's lifespan. This study describes two methods for decreasing the ripple in electromagnetic torque. Both circuit architecture and robust H∞ control techniques are considered. After simulating the two approaches, a list of requirements is provided for the maximum allowable amplitude of the inductance and the flux harmonics. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases (CVD) are a common global cause of death and are therefore a major health concern. Inhaled or ingested environmental heavy metals contribute to the development of CVD. The aim of this study was to address the limited information available on the effect of relevant dosages of metals in mixtures. Three metals with reported effects on the cardiovascular system (CVS) were identified, and these metals were copper (Cu), manganese (Mn) and mercury (Hg). In Sprague-Dawley rats, the adverse effects of copper (Cu), manganese (Mn) and mercury (Hg), alone and as part of mixtures, on the blood parameters, the aorta and heart were investigated. Forty-eight male Sprague-Dawley rats were randomly divided into eight groups (n = 6): control, Cu, Mn, Hg, Cu + Mn, Cu + Hg, Mn + Hg and Cu, Mn + Hg. The seven experimental groups received the metal mixtures at 100 times the World Health Organisation (WHO) safety limit for drinking water (2 mg/L for Cu, 0.4 mg/L for Mn and 0.06 mg/L for Hg) via oral gavage for 28 days. After 28 days, compared with the control, red blood cell levels were increased for Cu + Hg. All other measured blood parameters were unchanged. Morphological changes in the tunica media were connective tissue deposition and an abundance of collagen type I in the metal exposed aortic tissues. In the cardiac tissue of metal-exposed rats, changes in the cardiomyocyte and myofibrillar arrangement, with an increase in collagen type I and III was observed. Ultrastructurally, the aortic collagen and elastin band arrangement and the cardiac mitochondrial and myofibrillar arrangement and structures were altered in the experimental groups. These changes indicated that exposure to these metals in rats caused minor changes in the blood parameters, however, the changes in tissue and cellular structure indicated an increased risk for the development of CVD. [ABSTRACT FROM AUTHOR]

Understanding variations in metal levels in biota geographically and under different environmental conditions is essential to determining risk to organisms themselves and to their predators. It is often difficult to determine food chain relationships because predators may eat several different prey types. Horseshoe crab (Limulus polyphemus) eggs form the basis for a complex food web in Delaware Bay, New Jersey, USA. Female horseshoe crabs lay thumb-sized clutches of eggs, several cm below the surface, and often dislodge previously laid eggs that are brought to the surface by wave action, where they are accessible and critical food for migrant shorebirds. This paper compares metal and metalloid (chromium [Cr], cadmium [Cd], lead [Pb], mercury [Hg], arsenic [As] and selenium [Se]) concentrations in horseshoe crab eggs collected on the surface with concentrations in eggs from clutches excavated from below the sand surface, as well as examining metals in eggs from different parts of the Bay. The eggs were all collected in May 2019, corresponding to the presence of the four main species of shorebirds migrating through Delaware Bay. These migrating birds eat almost entirely horseshoe crab eggs during their stopover in Delaware Bay, and there are differences in the levels of metals in blood of different shorebirds. These differences could be due to whether they have access to egg clutches below sand (ruddy turnstones, Arenaria interpres) or only to eggs on the surface (the threatened red knot [Calidris canutus rufa] and other species of shorebirds). Correlations between metals in clutches were also examined. Except for As and Cd, there were no significant differences between the metals in crab egg clutches and eggs on the surface that shorebirds, gulls, and other predators eat. There were significant locational differences in metal levels in horseshoe crab eggs (except for Pb), with most metals being highest in the sites on the lower portion of Delaware Bay. Most metals in crab eggs have declined since studies were conducted in the mid-1990s but were similar to levels in horseshoe crab eggs in 2012. The data continue to provide important monitoring and assessment information for a keystone species in an ecosystem that supports many species, including threatened and declining shorebird species during spring migration. [ABSTRACT FROM AUTHOR]

Abstract This study investigated the characteristics of mercury emitted from a large-scale coal-fired power plant in Taiwan via intensive sampling campaigns. The air pollution control devices equipped in this coal-fired power plant include selective catalytic reduction, fabric filter and seawater flue gas desulfurization. During three sampling campaigns, mercury concentrations emitted from this large-scale coal fired power plant ranged from 0.04 to 0.35 μg Nm−3. In addition, solid and liquid samples including coal, bottom ash, fly ash and inlet/outlet seawater were collected and analyzed for mercury content to provide the mass flows of mercury in this plant. The results indicate that mercury emitted from this coal-fired power plant is dominated by Hg0, and the emission factor of mercury ranges from 0.37 to 3.37 mg Hg t−1 coal, which is relatively lower than those reported in other studies. The relative enrichment factor of mercury in fly ash (0.23–1.22) is significantly higher than that of bottom ash (0.10 × 10–3–0.89 × 10–3). Although this coal-fired power plant has a relatively low mercury atmospheric emission which accounts for 6.4% of the total mercury output, it is essential to further control mercury released from fly ash (62.6% of the total mercury output) and discharged seawater (33.7% of the total mercury output) to reduce environmental damage and human health effects.

The steel industry is an important source of anthropogenic mercury (Hg) emissions. Hg is harmful to human health, causing symptoms such as dizziness, pneumonia, and renal failure. So, how do we reduce Hg emissions from the steelworks? What possibilities exist for Hg emission reduction? Firstly, in this study, the flow paths of Hg in the steelworks were described quantitatively using the substance flow analysis method, and the characteristics of the input and output of Hg-containing subjects were analyzed. Secondly, based on the Hg flow network, the circulation characteristics of Hg and the emission characteristics of Hg-containing pollutants were analyzed in the steelworks. Finally, according to the distribution of Hg in the steelworks, the emission reduction potential was examined at the source and end-of-pipe. The results showed that Hg, which mostly originated from coal, limestone, and iron ore concentrate in the steel production process, was mostly exported with waste gas and wastewater, primarily in the form of waste gas. The input, circulation, and output of Hg were 362.77, 3.25, and 392.55 mg/t crude steel (CS), respectively. Through source reduction and end-of-pipe treatment, the reduction rates of pollutants in the steelworks were 28.74% and 75.37%, respectively. [ABSTRACT FROM AUTHOR]