Mercury Exposure Research Articles

The Relationship Between Mercury Exposure and Membranous Nephropathy: Case Reports and Meta‐Analysis

ABSTRACTTo investigate the clinical characteristics of patients with membranous nephropathy (MN) and the therapeutic efficacy of Sodium Dimercaptosulphonate (DMPS), as well as the relationship between mercury (Hg) exposure and MN, we investigated the clinical manifestations and treatment outcomes of six patients with MN and searched the China National Knowledge Internet (CNKI), PubMed, Web Of Science, and Embase databases for relevant studies on Hg exposure and MN published from the inception of the databases to April 2024. Data analysis was performed using SPSS 26.0 and Stata 16.0. We found that (1) the clinical symptoms of MN patients were mainly characterized by proteinuria, edema, hypoproteinemia, and hyperlipidemia. Comparative analysis before and after DMPS treatment showed a decrease in 24‐h urinary Hg, 24‐h urinary protein, and total cholesterol levels, as well as an increase in serum albumin levels (p < 0.05). (2) Two MN patients received DMPS for sole Hg detoxification treatment, whereas four patients received Hg detoxification combined with hormone therapy, and all patients showed significant improvement in symptoms after treatment. (3) Among the 564 articles, four met the inclusion criteria. The results showed that Hg exposure increased the incidence of MN by 5.74 times (95% confidence interval [CI] = 2.57, 12.83). The clinical symptoms of MN patients are mostly manifested as proteinuria, edema, hypoproteinemia, and hyperlipidemia. DMPS Hg detoxification treatment is effective for Hg‐induced MN. Hg exposure can increase the prevalence of MN, therefore making it necessary to take prudent measures to reduce the risk of Hg exposure.

Peptide-Based Rapid and Selective Detection of Mercury in Aqueous Samples with Micro-Volume Glass Capillary Fluorometer

Mercury, a toxic heavy metal produced through both natural and anthropogenic processes, is found in all of Earth’s major systems. Mercury’s bioaccumulation characteristics in the human body have a significant impact on the liver, kidneys, brain, and muscles. In order to detect Hg2+ ions, a highly sensitive and specific fluorescent biosensor has been developed using a novel, modified seven amino acid peptide, FY7. The tyrosine ring in the FY7 peptide sequence forms a 2:1 complex with Hg2+ ions that are present in the water-based sample. As a result, the peptide’s fluorescence emission decreases with higher concentrations of Hg2+. The FY7 peptide’s performance was tested in the presence of Hg2+ ions and other metal ions, revealing its sensitivity and stability despite high concentrations. Conformational changes to the FY7 structure were confirmed by FTIR studies. Simultaneously, we designed a miniaturized setup to support an in-house-developed micro-volume capillary container for volume fluorometry measurements. We compared and verified the results from the micro-volume system with those from the commercial setup. The micro-volume capillary system accommodated only 2.9 µL of sample volume, allowing for rapid, sensitive, and selective detection of toxic mercury (II) ions as low as 0.02 µM.

Green and Mild Fabrication of Magnetic Poly(trithiocyanuric acid) Polymers for Rapid and Selective Separation of Mercury(II) Ions in Aqueous Samples

The removal and detection of highly toxic mercury(II) ions (Hg2+) in water used daily is essential for human health and monitoring environmental pollution. Efficient porous organic polymers (POPs) can provide a strong adsorption capacity toward heavy metal ions, although the complex synthetic process and inconvenient phase separation steps limit their application. Hence, a combination of POPs and magnetic nanomaterials was proposed and a new magnetic porous organic polymer adsorbent was fabricated by a green and mild redox reaction in the aqueous phase with trithiocyanuric acid (TA) and its sodium salts acting as reductive monomers and iodine acting as an oxidant. In the preparation steps, no additional harmful organic solvent is required and the byproducts of sodium iodine are generally considered to be non-toxic. The resulting magnetic poly(trithiocyanuric acid) polymers (MPTAPs) are highly porous, have large surface areas, are rich in sulfhydryl groups and show easy magnetic separation ability. The experimental results show that MPTAPs exhibit good adsorption affinity toward Hg2+ with high selectivity, rapid adsorption kinetics (10 min), a large adsorption capacity (211 mg g−1) and wide adsorption applicability under various pH environments (pH 2~8). Additionally, MPTAPs can be reused for up to 10 cycles, and the magnetic separation step of MPTAPs is fast and convenient, reducing energy consumption compared to centrifugation and filtration steps required for non-magnetic adsorbents. These results demonstrate the promising capability of MPTAPs as superior adsorbents for effective adsorption and separation of Hg2+. Based on this, the prepared MPTAPs were adopted as magnetic solid-phase extraction (MSPE) materials for isolation of trace Hg2+ from aqueous samples. Under optimized conditions, the extraction and quantification of trace Hg2+ in water samples were accomplished using inductively coupled plasma mass spectrometry (ICP-MS) detection after MSPE procedures. The proposed MPTAPs-based MSPE-ICP-MS method is efficient, rapid, sensitive and selective for the determination of trace Hg2+, and was successfully employed for the accurate analysis of trace Hg2+ in tap water, wastewater, lake water and river water samples.

Gut heavy metal and antibiotic resistome of humans living in the high Arctic

Contaminants, such as heavy metals (HMs), accumulate in the Arctic environment and the food web. The diet of the Indigenous Peoples of North Greenland includes locally sourced foods that are central to their nutritional, cultural, and societal health but these foods also contain high concentrations of heavy metals. While bacteria play an essential role in the metabolism of xenobiotics, there are limited studies on the impact of heavy metals on the human gut microbiome, and it is so far unknown if and how Arctic environmental contaminants impact the gut microbes of humans living in and off the Arctic environment. Using a multiomics approach including amplicon, metagenome, and metatranscriptome sequencing, we identified and assembled a near-complete (NC) genome of a mercury-resistant bacterial strain from the human gut microbiome, which expressed genes known to reduce mercury toxicity. At the overall ecological level studied through α- and β-diversity, there was no significant effect of heavy metals on the gut microbiota. Through the assembly of a high number of NC metagenome-assembled genomes (MAGs) of human gut microbes, we observed an almost complete overlap between heavy metal-resistant strains and antibiotic-resistant strains in which resistance genes were all located on the same genetic elements.

Electrochemical Biosensor for Detecting both Pb2+ and Hg2+ in Human Blood

Many studies have demonstrated that lead ion ( Pb2+ ) and mercury ion ( Hg2+ ) are harmful to human health. Lead was found to accumulate in the kidney, leading to oxidative stress, apoptosis, and inflammation in the nephrons, and possess marked testicular toxicity. Mercury is well-known to produce nephrotoxicity, inflammatory responses and induce oxidative stress and apoptosis. These heavy metals can enter the human body in various ways, such as through skin or inhalation routes, or contaminated drinking water and food. But heavy metal poisoning is not easy to diagnose because existing detecting measures has many disadvantages cause them can’t widely spread. So, seeking an easy way to detect them in human blood to discover lead or mercury poisoning is an unmet need. This paper develops a new reusable biosensor for detecting both Pb2+ and Hg2+ in human blood. This work is based on the reaction between guanine and Pb2+ form of G-quadruplex and Hg2+ connect two thymines together cause the variation of electrochemical signal. The signal is magnified by methylene blue-gold nanoparticles (MB-AuNP) to increase the limit of detection Although the reuse part of sensor is still in theory, but this approach can make the cost of sensor low and create the feasibility of recycle. Overall, providing a new idea to make contributions to the prevention of heavy metal poisoning is the reason why this study is conducted.

Effects of mercury and magnetic fields on the activity of proteinases and glycosidases in the intestine of common carp Cyprinus carpio.

Aquatic ecosystems are increasingly affected by anthropogenic pollution, including heavy metals like mercury, which accumulate in organisms and cause harmful effects. At the same time, human activities such as industrial operations and the use of electric power lines also alter the magnetic background in natural water bodies. However, the interaction between mercury exposure and magnetic fields remains poorly understood. This study aimed to investigate the combined effects of mercury and magnetic fields on the digestive enzyme activity of common carp (Cyprinus carpio), focusing on the relevance of magnetic fields due to their increasing presence in industrialized environments. Two groups of fish were fed diets with low (0.02mg/kg) or high (0.27mg/kg) mercury content for 6months and exposed to extremely low-frequency magnetic fields or hypomagnetic conditions. Results showed significant differences in mercury accumulation between groups, with higher levels in carps fed with high-mercury content diets. These fish also exhibited increased body length and weight compared to those on a low-mercury diet. The amylolytic activity (total activity of enzymes hydrolyzing starch: α-amylase, glucoamylase, and maltase) and proteolytic activity (total activity of serine proteinases) in the fish intestine were assessed. Magnetic exposure had contrasting effects on enzyme activity, depending on mercury levels in the diet. Fish fed the low-mercury diet exhibited decreased amylolytic activity following magnetic field exposure, while fish on the high-mercury diet showed increased activity. Proteolytic activity followed a similar pattern, with opposite effects observed between the two dietary groups. These findings suggest that mercury accumulation alters the biological response to magnetic fields, possibly through compensatory biochemical mechanisms. Understanding the interactions between toxic substances and magnetic fields is critical for improving environmental risk assessments.

Unveiling mercury exposure sources in e-waste recycling with biomonitoring - A Portuguese case study

Abstract Background Mercury (Hg), a global pollutant, poses risks to both human and environmental health. The management and recycling of electrical and electronic waste (e-waste) is recognized as having the potential to promote workers’ exposure to this pollutant. Human biomonitoring (HBM) is a tool that can be used to evaluate exposure and monitor the health of workers. The objective of this study was to characterize exposure of workers from an e-waste recycling company and to analyze the relevance that HBM holds in the detailed characterization of exposure. Methods A cross-sectional observational study was conducted using data collected within the framework of the European Human Biomonitoring Initiative (HBM4EU). Data from environmental monitoring (settled dust) and biological monitoring (urine and hair) of 30 workers potentially exposed to Hg were analyzed in comparison with 12 unexposed workers from other occupational settings (controls). Results Exposed workers did not exhibit significantly higher concentrations of Hg in urine when compared to control workers. We found a significantly positive correlation between the concentration of Hg in urine (ρ = 0.688; p ≤ 0.001) and hair (ρ = 0.470; p ≤ 0.01) and the consumption of fish and shellfish. Conclusions Diet appears to be the most significant source of Hg in this context. These results suggest the importance of information and dietary habits to prevent mercury exposure. HBM stands out as an essential tool for identifying the most relevant exposure sources and risk management measures for workers and the general population. Key messages • Diet appears to be the most significant Hg source in workers from a Portuguese e-waste company. • HBM stands out as essential for identifying the most relevant exposure sources and risk management.

Viscoelastic Fluid Focusing Chip-ICP-MS Single-Cell Analysis Enables Elucidating the Effect of Extracellular Polymeric Substances on Bioaccumulation of Hg2+/HgS in Microcystis aeruginosa Cell.

Understanding the interactions between mercury and microalgae, especially the interactions between inorganic mercury (IHg) and extracellular polymeric substances (EPS, a protective barrier between cells and their external environment), is essential for elucidating mercury's toxicological mechanisms. Given the inherent cell heterogeneity, a novel analysis system of an online viscoelastic fluid focusing chip-time-resolved analysis inductively coupled plasma mass spectrometry has been developed to investigate the bioaccumulation of HgS nanoparticles and Hg2+ in single Microcystis aeruginosa (M. aeruginosa) cells, exploring the interaction mechanisms between HgS/Hg2+ accumulation in algal cells and EPS. The single-cell analysis results reveal minimal bioavailability of HgS within algal cells, with mercury's toxicity to M. aeruginosa being species-dependent. Notably, algal cells exhibited more heterogeneity in HgS uptake than in Hg2+ uptake. Under Hg2+/HgS stress, M. aeruginosa cells with EPS removed (EPS-R algal cells) showed an increased level of bioaccumulation of mercury compared to those with EPS (EPS-C algal cells), highlighting the critical role of EPS in mercury bioaccumulation. Overall, the designed viscoelastic fluid microfluidic focusing chip integrates focusing and cleaning functions, featuring easy fabrication, simple operation, low sample loss, and relatively high throughput. Under the optimal conditions, the sample throughput is 1195 min-1 and the cell recovery is 90%. Besides, this research offers novel insights into the interaction mechanisms between Hg2+/HgS and EPS in microalgal cells and unveils the specific toxic effects of Hg2+/HgS on M. aeruginosa at the single-cell level, contributing to a deeper understanding of mercury's ecological and toxicological impact in aquatic environments.

The functional activity of the brain in patients with occupational chronic mercury intoxication against background of the treatment of insomnia disorders

Introduction. In patients with chronic mercury intoxication, insomnia disorders are much more common than in the general population. Persistent emotional disorders in combination with severe sleep disturbances may contribute to the progression of cognitive dysfunction in patients in the late post-exposure period of chronic mercury intoxication. The purpose of the study was to analyze the trend in electroencephalography indices and study cognitive evoked potentials in patients with occupational chronic mercury intoxication to optimize the treatment of insomnia. Materials and methods. Two groups of 30 patients with occupational chronic mercury intoxication, who worked at the enterprises of Usolyekhimprom LLC and Sayanskhimplast OJSC, were examined. In the first group of patients received the first treatment option, the average age was 56±0.71 years, in the second group, cases received the second treatment regimen, were of 57.1±3 years. Before and after treatment, there were carried out neurophysiological studies including polysomnography, electroencephalography, and a study of cognitive evoked potentials P300. Results. After the implementation of the treatment regimen in the first group, positive changes in the main indices of polysomnography were revealed as follows: decrease in the time of falling asleep and time of wakefulness in the bed, increase in total sleep time and the representation of delta sleep, increase in the sleep efficiency index, etc., electroencephalography (decrease in the delta index – rhythm and an increase in the alpha rhythm index), and cognitive evoked potentials (decreased latency and increased P300 amplitude). In the second group, there were registered positive alterations only in three neurophysiological indices: a decrease in the latent period of the 1st stage of sleep, a decline in the delta rhythm index and a fall in P300 latency. Limitations. The results cannot be generalized to workers as the group included only men. Conclusion. According to neurophysiological studies, improvement in polysomnography parameters during the treatment of insomnia in patients in the late post-contact period of chronic mercury intoxication was accompanied by an improvement in concentration and an increase in the rate of psychomotor response.

Association between blood total mercury and psoriasis: The NHANES 2005-2006 and 2013-2014: A cross-sectional study.

An inflammatory skin condition called psoriasis results from immune system interactions that are out of balance. Reactive oxygen species are produced as a general mechanism of mercury toxicity. This study aimed to determine whether there was an association between blood total mercury and psoriasis in US adults. Utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2005-2006 and 2013-2014. NHANES is a national research survey program every two years to assess the population's nutritional and physical health. The relationship between blood total mercury and psoriasis was studied using multivariable logistic regression models and smooth curve fitting. Subgroup analysis and interaction tests were used to investigate if this association was stable across populations. After adjusting for several factors, we found a positive association between blood total mercury and psoriasis in 6086 participants. According to the fully adjusted model, each 1-unit increase in blood total mercury was associated with an 8% increase in the prevalence of psoriasis [1.08 (1.03, 1.14)]. The favorable association seems to be more pronounced in non-diabetes. Our research shows a positive association between psoriasis and blood total mercury in US adults. The results of this study need to be supported by additional prospective research.

Rational Design of Regenerable Amino-Functionalized Fluorescent Covalent Organic Framework for the Exclusive Detection of Mercury(II).

Goal-oriented development of novel covalent organic frameworks (COFs) to construct a sensing platform for highly toxic mercury (II, Hg2+) is of tremendous significance. Recently, numerous COFs with sulfur-based ligands were developed for Hg2+ monitoring; however, strong binding of Hg2+ by sulfur makes their regeneration very tough. Herein, we designed and developed an amino-functionalized fluorescent COF (COF-NH2) through facile postmodification for Hg2+ detection in which the π-conjugation skeleton is the signal reader and the nitrogen-based side is the highly selective Hg2+ receptor. More importantly, this nitrogen-based receptor permits the reversible binding of Hg2+. As a sensing platform, the outstanding performance of COF-NH2 for Hg2+ detection was reached with respect to high sensitivity with an ultralow detection of 15.3 nM, real-time response with rapid signal change of 10 s, and facile visualization with significant fluorescence color change. Expectedly, COF-NH2 obtained facile recycling which still shows excellent response performance toward Hg2+ after six cycles based on the reversible interaction between amino groups and Hg2+. Our work not only shows an attractive foreground of fluorescent COF for Hg2+ detection but also emphasizes the easy construction of novel COF materials via the rational introduction of metal ligands for the recognition of other metal ions.

Effects of Gingko Biloba Extract and L-Ascorbic Acid on Some Hematological, Biochemical, and Hepatic-Architectural Alterations in Mercury Chloride Intoxicated Adult Wistar Rat.

The study investigated the effects of Ginkgo biloba and Ascorbic acid (A.A) on mercury chloride (HgCl2) toxicity in Wistar rats. Forty-two adult Wistar rats were randomly divided into seven groups (n=6). Group I served as control. Groups II–VII received 5 mg/kg of HgCl2. Groups III and IV received 100 mg/kg and 500 mg/kg of A.A respectively, while groups V and VI daily received 100 mg/kg and 500 mg/kg of EGB761 respectively. Group VII received 100 mg/kg of A.A and EGB761. All administration were done orally, once daily for 21 days. Mercury exposure caused significant (p<0.05) decreases in RBC (3.62.00±0.75), hemoglobin (8.67±0.14), and PCV (32.93±0.47) in group II when compared to the control group, while significantly (p<0.05) increasing white blood cell count (18.57±1.51). Liver function tests significantly (p<0.05) increased Alanine transaminase (1.38±1.51), Aspartate Transaminase (10.11±4.21), and Alkaline Phosphatase (1.89±0.51) in group II when compared to Control. Biochemical analysis revealed a significant (p<0.05) increase in malondialdehyde levels and a significant (P<0.05) decrease in superoxide dismutase (3.86 ± 0.69), glutathione (10.08 ± 2.13), and catalase (3.65 ± 0.2) levels in group II. However, treatment with ascorbic acid and EGB761 significantly (P<0.05) increased in Groups IV (6.15 ± 0.38); VI (6.28 ± 0.40), and VII (6.19 ± 0.41), SOD levels in Groups IV (6.15 ± 0.38); VI (6.28 ± 0.40) and VII (6.19 ± 0.41) and GSH level when compared to the HgCl2 group. Histological examination showed moderate hepatocyte necrosis in group II, while treatment with EGB761 and A.A showed moderate healing, binucleate nuclei, and a slight decrease of distorted sinusoids and normalization of liver structure. The study concludes that EGB761 and A.A have hepatoprotective effects on mercury-induced hepatotoxicity in a dose-dependent manner. The findings suggest that these antioxidants may be useful in mitigating the harmful effects of mercury exposure on the liver.

Monitoring of mercury ion in environmental media and biological systems using a red emissive fluorescent probe with a large Stokes shift

The development of practical fluorescent probe for detecting toxic mercury ions (Hg2+) is desirable for environmental assurance and public health. In this study, a new red emissive fluorescent probe (KJL) was designed and synthesized for monitoring trace Hg2+ both in vitro and in vivo with distinct features including ideal response rate (within 4 min), red emission (596 nm), large Stokes shift (162 nm), highly sensitivity (LOD = 4.79 nM) and excellent specificity. KJL also validated the good capability for accurately monitoring trace Hg2+ levels in actual samples (faucet water, drinking water, river water, lake water, urine and serum) and possessed the eye-catching ability in visualization of Hg2+ under environmental/biological conditions, which revealed the great potential of this red-emitting fluorescent probe for practical applications in complex environmental and biological systems.

Blood mercury concentrations in preschool children and potential risk factors in São Paulo, Brazil

Environmental exposure of preschool children to mercury can elevate blood mercury levels (BML) and negatively affect their health. This study aimed to determine BML in preschool children from Brazil's largest city and explore potential associated risk factors. Blood samples were collected in 2013 from 2436 children (age 1–5 years) attending 50 daycare centers (DCC) located in São Paulo, Brazil. Parents or guardians answered questionnaires collecting information on sociodemographics and potential risk factors. BML was determined by Cold Vapor Atomic Absorption Spectrophotometry (CV-AAS) and categorized using a cutoff point of 2.77 μg L⁻1, corresponding to the 75th percentile. Multiple logistic regression was performed (p < 0.05). Data were georeferenced and associations with air pollution, wind frequency and direction were evaluated. The results showed a geometric mean for BML of 1.65 μg L⁻1 (95% CI: 1.60–1.70), arithmetic mean of 2.15 μg L⁻1 (95% CI: 2.09–2.22), 75th percentile of 2.77 μg L⁻1 (95% CI: 2.67–2.91) and 95th percentile of 5.51 μg L⁻1 (95% CI: 5.18–5.92). DCCs located in the Northwest and East zones (p < 0.001) and fish consumption in the past two days (p = 0.04) were associated with high BML. The elevated BML observed in children living in the eastern zone might be attributed to the southeasterly winds passing through a petrochemical complex located nearby. The 95th percentile of BML in this study exceeded the U.S. 95th percentile by five times. BML in São Paulo preschool children was associated with individual and environmental risk factors. This finding highlights the need to identify and control hot spots in São Paulo, Brazil, especially in peripheral and surrounding areas, where individuals are more vulnerable. Further research is needed in Latin America to identify additional sources of urban environmental mercury exposure and guide interventions for protecting the environment and safeguarding children's health.

Unexpected anthropogenic emission decreases explain recent atmospheric mercury concentration declines.

Anthropogenic activities emit ~2,000 Mg y-1 of the toxic pollutant mercury (Hg) into the atmosphere, leading to long-range transport and deposition to remote ecosystems. Global anthropogenic emission inventories report increases in Northern Hemispheric (NH) Hg emissions during the last three decades, in contradiction with the observed decline in atmospheric Hg concentrations at NH measurement stations. Many factors can obscure the link between anthropogenic emissions and atmospheric Hg concentrations, including trends in the reemissions of previously released anthropogenic ("legacy") Hg, atmospheric sink variability, and spatial heterogeneity of monitoring data. Here, we assess the observed trends in gaseous elemental mercury (Hg0) in the NH and apply biogeochemical box modeling and chemical transport modeling to understand the trend drivers. Using linear mixed effects modeling of observational data from 51 stations, we find negative Hg0 trends in most NH regions, with an overall trend for 2005 to 2020 of -0.011 ± 0.006 ng m-3 y-1 (±2 SD). In contrast to existing emission inventories, our modeling analysis suggests that annual NH anthropogenic emissions must have declined by at least 140 Mg between the years 2005 and 2020 to be consistent with observed trends. Faster declines in 95th percentile Hg0 values than median values in Europe, North America, and East Asian measurement stations corroborate that the likely cause is a decline in nearby anthropogenic emissions rather than background legacy reemissions. Our results are relevant for evaluating the effectiveness of the Minamata Convention on Mercury, demonstrating that existing emission inventories are incompatible with the observed Hg0 declines.

The Neuroprotective Effect of Calotropis procera Against Toxicity of Mercury Chloride

Background: Central nervous system intoxication can result from exposure to various toxins, including mercury chloride. Although several chelating agents are available for mercury chloride detoxification, their efficacy can diminish over time. Calotropis procera, a medicinal plant, has shown potential as a protective agent against mercury chloride-induced brain damage. This study aims to evaluate the protective effects of Calotropis procera in mitigating mercury chloride toxicity. Experimental animal design: This study investigates the protective effects of Calotropis procera against mercury chloride toxicity in Wistar albino rats. A total of 36 rats, comprising both males and females, were housed under controlled laboratory conditions and divided into two main groups based on five animals. Each group was further subdivided into five subgroups: a control group, a group treated with Calotropis procera, a group treated with mercury chloride, a group treated with both mercury chloride and Calotropis procera and a group receiving Calotropis procera alongside mercury chloride. Treatments were administered for 20 days. After the treatment period, the rats were euthanised, and brain tissues were collected for histopathological analysis. After the brain tissues were fixed in 10% saline-buffered formalin, they were processed through a series of ascending grades of ethanol to dehydrate them. The tissues were then cleared in xylene and embedded in paraffin. The paraffin-embedded brains were treated three times with pure paraffin to ensure proper infiltration and were subsequently moulded into blocks. Sections of 5 µm thickness were prepared using a Leica microtome and stained with Haematoxylin and Eosin (H&amp;E) for histopathological examination. The study adhered to ethical guidelines and was approved by the relevant regulatory body. The results of this study demonstrated that mercury chloride caused significant cerebral toxicity, manifesting as inflammation and pyknosis of the nuclei. Calotropis procera reduced mercury toxicity and preserved the nuclei in male rats. In female rats, Calotropis procera completely preserved the brain tissue.

Characterizing visual field loss from past mercury exposure in an Indigenous riverine community (Grassy Narrows First Nation, Canada): a cluster-based approach

BackgroundBetween 1962 and 1975, a chlor-alkali plant in Canada discharged approximately 9 metric tons of mercury (Hg) into the Wabigoon River. Over the following decades, biomarkers of Hg exposure of persons from Grassy Narrows First Nation (Asubpeeschoseewagong Anishinabek), located downriver from the discharge, reflected Hg concentrations in fish. Hg exposure is known to target the calcarine fissure, resulting in visual field (VF) loss. Most studies and clinical reports focus solely on peripheral VF loss; little is known about the impact of Hg on the central and paracentral portions. The present study sought to characterize the patterns of VF loss with respect to past and current Hg.MethodsA 28-year hair-Hg (HHg) database, created from a 1970–97 government biomonitoring program, served to select study participants with ≥ 4 year-based HHg measurements (n = 81). Blood-Hg was assessed for current exposure. Light sensitivity thresholds across the VF were analyzed monocularly, using a Humphrey Field Analyzer (HFA). Following post-hoc exclusions, based on HFA interpretation indices, 65 participants were retained. Both eyes were combined for analyses (n = 130 eyes). Unsupervised hierarchical clustering of HFA plot data was used to identify patterns of VF loss. A series of mixed effects models (MEM) were performed to test the associations for current Hg exposure with respect to HFA interpretation indices and clusters, as well as for longitudinal past Hg exposure.ResultsThe clustering approach decomposed the light sensitivity deficits into 5 concentric clusters, with greatest loss in the peripheral clusters. No relation was observed between any of the cluster scores and current blood-Hg. VF deficits increased with past Hg exposure. Longitudinal MEM showed that HHg was significantly (p < 0.05) associated with all peripheral, paracentral, and central cluster scores, as well as with HFA interpretation indices.ConclusionsPast Hg exposure in Grassy Narrows First Nation was associated with present day VF loss. The cluster-based location-specific approach identified patterns of VF loss associated with long-term Hg exposure, in both the peripheral and the central areas. The functional implications of this type of visual loss should be investigated.

Analysis of Differential Gene Expression under Acute Lead or Mercury Exposure in Larval Zebrafish Using RNA-Seq.

This study was first conducted to investigate the effects of acute lead exposure on developing zebrafish embryos or larvae from 24 to 120 h post-fertilization (hpf). Our data showed that treatment with 50-200 μM lead significantly affected larval survivability and morphology compared to the respective control. Second, we chose 120 hpf larvae treated with 12.5 μM lead for RNA sequencing due to its exposure level being sufficient to produce toxic effects with minimum death and lead bioaccumulation in developing zebrafish. A total of 137.45 million raw reads were obtained, and more than 86% of clean data were mapped to the zebrafish reference genome. Differential expression profiles generated 116 up- and 34 down-regulated genes upon lead exposure. The most enriched GO terms for representative DEGs were ion transport and lipid metabolism. Third, a comparison with the dataset of mercury-regulated gene expression identified 94 genes (64 up-regulated and 30 down-regulated) for exposure specific to lead, as well as 422 genes (338 up-regulated and 84 down-regulated) for exposure specific to mercury. In addition, 56 genes were co-regulated by micromolar mercury and lead treatment, and the expression of thirteen genes, including mt2, ctssb.1, prdx1, txn, sqrdl, tmprss13a, socs3a, trpv6, abcb6a, gsr, hbz, fads2, and zgc:92590 were validated by qRT-PCR. These genes were mainly associated with metal ion binding, proteolysis, antioxidant activity, signal transduction, calcium ion or oxygen transport, the fatty acid biosynthetic process, and protein metabolism. Taken together, these findings help better understand the genome-wide responses of developing zebrafish to lead or mercury and provide potential biomarkers for acute exposure to toxic metals.

7439 Mercury toxicity presenting as Pheochromocytoma

Abstract Disclosure: A. Ansar: None. K. McNerney: None. B.A. Marshall: None. Background: Mercury intoxication is a rare cause of hypertension in children and can mimic other endocrinopathies such as pheochromocytoma. Mercury affects catecholamine metabolism and can cause elevated catecholamine levels, thereby incorrectly suggesting a catecholamine-secreting tumor. Clinical Case: An 8-year-old girl presented to the ED with progressive night sweats, intractable migratory myalgias, hypertension and tachycardia. Patient was in her usual state of health until 2 weeks before presentation when she started to have worsening intermittent pains in her chest, arms, back, and knees. She also experienced restlessness and inability to sleep. On presentation she was hypertensive, with blood pressure of 146/116 mm Hg while calm, heart rate 125 bpm, afebrile. She was anxious, irritable, and seemed uncomfortable. Her skin was dry and rough with a scaly eczematous rash on the arms and legs. She had persistently elevated blood pressure in upper and lower extremities, unremarkable echocardiogram and electrocardiogram, and a normal result on fundoscopic examination. Her initial electrolytes, creatinine, and urinalysis were all normal and remained so on serial evaluations. Urine drug screen was negative. Thyroid function panel showed normal TSH with slightly elevated Free T4 2.28 ng/dL (0.9-1.7), but a normal Free T3 3.9 pg/mL (2.0-4.4) and Free T4 by equilibrium dialysis 1.8 ng/dL (0.8 - 2.0). CT of the chest, abdomen and pelvis was negative and did not show any lesions. Plasma renin activity was 4.6 ng/mL/hour, supine, (&amp;lt;2.0) and plasma aldosterone level &amp;lt; 4.0 ng/dL (&amp;lt; 40 supine) were normal. 24-hour urinary norepinephrine was 90 μg/24h (13-65), epinephrine 37 μg/24h (0.2-10), urine metanephrines 195 μg/24h (18-144), urine normetanephrines 305 μg/24h (29-145), all elevated. Further history taking revealed that patient was taking Ayurvedic supplements prepared by hand by medicinal personnel in India for 3 months prior to presentation. These were stopped 2 weeks prior to her presentation, when she first became symptomatic. Her blood mercury level was 11 ng/mL (n &amp;lt;9), and urinary mercury excretion 67 μg/24 hours (n&amp;lt;10), both obtained 3 weeks after stopping supplementation. She was started on oral chelation therapy with succimer 10 mg/kg/day. Her hypertension was controlled with doxazosin. One week after initiation of therapy, her symptoms improved, and she became normotensive. Her acrodynia and irritability resolved. Urine metanephrine levels will be repeated at upcoming clinic follow up. Conclusion: Mercury toxicity should be considered in the differential of pheochromocytoma to avoid extensive diagnostic testing and morbidity associated with it. Lead, mercury, and arsenic have been detected in traditionally prepared Ayurvedic supplements. A careful history of intake of supplements can be important in cases with unusual symptomatology. Presentation: 6/3/2024

Toxic Metal Injustice? Socioeconomic status at birth and exposure to airborne pollution

We combine administrative data on socioeconomic status (SES) with high-resolution data on residential locations, local pollution levels, industrial facilities, as well as land cover information to investigate whether exposure to airborne toxic metals (arsenic, lead, and mercury) is unequally distributed within the population of newborn children in Sweden. We find that the spatial distribution of SES among newborns weakly correlates with the distribution of toxic metals at the national level and in the largest cities, indicating negligible sorting in this dimension. If anything, high SES children are disproportionately more exposed, residing in urban areas with higher levels of traffic and industrial activities. This leads us to conclude that environmental injustice regarding airborne arsenic, lead, and mercury exposure is not a major concern in Sweden.