Chronic low-level hydrogen sulfide exposure and potential effects on human health: A review of the epidemiological evidence

Efficient ppt-Level H2S Gas Sensor Based on YSZ and α-Fe2O3 Nanofoam Sensing Electrode

Herein, porous α-Fe2O3 nanofoam was successfully synthesized and used as a sensing electrode to fabricate a yttria-stabilized zirconia (YSZ) mixed-potential hydrogen sulfide (H2S) sensor for real-time monitoring of hazardous H2S gas. The sintering temperature was adjusted to modify the microstructure of the sensing electrode material and its electrochemical reaction intensity to H2S, enhancing the sensor's performance. Among the tested materials, α-Fe2O3 nanofoam sintered at 800 °C exhibited the highest electrochemical catalytic activity toward H2S in electrochemical tests, suggesting its suitability as a sensing electrode material for YSZ-based H2S sensors. The sensor incorporating α-Fe2O3 nanofoam sintered at 800 °C achieved the highest response of -273 mV to 10 ppm of H2S at 625 °C. Moreover, this sensor exhibited a low detection limit of 100 ppt and, within the H2S concentration range of 0.5-10 ppm, a high sensitivity of -180.3 mV/decade, outperforming other reported YSZ-based H2S sensors. Furthermore, this fabricated sensor exhibited excellent repeatability, selectivity, and long-term stability, indicating its potential for industrial safety early warnings and precise environmental monitoring. This study provides a valuable reference for designing porous sensing electrode materials and enhancing the sensing performance of mixed-potential gas sensor.

Adsorptive removal of gaseous contaminants using biomass-based adsorbents

Biomass-based adsorbents have emerged as attractive materials for the adsorptive removal of gaseous pollutants due to their abundance in nature, low cost, and environmental friendliness. The modification of the adsorbent surfaces has been regarded as an intriguing technique for improving and enhancing their adsorption capacity for efficient removal of pollutants. The present study investigates the most recent developments and applications of biomass-derived adsorbents for removing various gaseous contaminants from air and gas streams. The use of biomass materials such as agricultural waste and wood residue to synthesize adsorbents provides a long-term solution to environmental pollution. This is due to the fact that biomass-derived adsorbents can be designed to have a large surface area, porosity, and surface functionality, thereby increasing their adsorption capacity and selectivity for target pollutants using a variety of chemical processes such as carbonization, activation, and modification. This study presents a comprehensive report on the use of biomass-based adsorbents for the removal of various gaseous pollutants such as carbon dioxide (CO2), volatile organic compounds (VOCs), nitrogen oxides (NO x ), sulfur dioxide (SO2), hydrogen sulphide (H2S) and multi-gas components. The surface chemistry of biomass adsorbents, in addition to their porous nature, is discussed. Multi-gas adsorption properties and the regeneration of biomass adsorbent are also discussed. The challenges and future prospects for developing biomass-based adsorbents for gaseous pollutant removal are also discussed, emphasizing the importance of a thorough understanding of adsorption mechanisms, scalability of manufacturing processes, and integration with existing air purification technologies. The findings of this study present biomass-derived adsorbents as a promising alternative for mitigating the challenges associated with the danger of gaseous pollutants, contributing to sustainable environmental management and public health protection.

A Near-Infrared Fluorescent Probe with a Large Stokes Shift for Detecting Hydrogen Sulfide in Environmental Waters, Wine Samples, and Living Systems

Hydrogen sulfide (H2S) is closely related to physiological diseases, environmental pollution, food safety, and plant growth. Herein, a new nopinone-based near-infrared fluorescent probe has been developed to detect H2S with superior performance, including a large Stokes shift, low detection limit, good selectivity, and fast response time. NPD-H2S was used to detect H2S in environmental water and wine samples quantitatively. In addition, NPD-H2S could be used to fabricate nanofiber membranes as a portable tool for sensitively detecting H2S vapor using a smartphone. Moreover, NPD-H2S has been effectively used to image H2S in HeLa cells, MCF-7 cells, and zebrafish. More importantly, the probe monitored the presence of H2S upregulation processes in Arabidopsis thaliana under salt stress by bioimaging. This work provides a concept for the intervention of external stresses in plant cultivation. Therefore, probe NPD-H2S can effectively monitor the fluctuation of H2S in the environment and living systems.

Mitochondrial homeostatic imbalance-mediated developmental toxicity to H2S in embryonic zebrafish

Hydrogen sulfide (H2S) is a pervasive environmental and industrial pollutant that poses a substantial threat to human health. Even short-term exposure to H2S can result in severe respiratory and neurological damage. However, the underlying mechanisms of its biotoxicity remain unclear. Our study demonstrated that continuous exposure to 30 μM (1.02 ppm), whin environmentally H2S concentration range, results in notable developmental toxicity, including high mortality rates, morphological deformities, and behavioral abnormalities, in zebrafish larvae. Through transcriptomic analysis, examination of mitochondrial structure and function, and tissue and cellular staining, we found that H2S exposure disrupted mitochondrial dynamics, autophagy, and biogenesis, leading to an imbalance in mitochondrial homeostasis. This disruption induced oxidative stress and extensive apoptosis. Nitric oxide (NO) is a multifunctional signaling molecule known to target and regulate mitochondrial regeneration. In our study, we discovered that sodium nitroprusside (SNP), an NO donor, can activate the NO-sGC-cGMP signaling pathway. This activation improves the homeostatic regulation of mitochondrial dynamics, autophagy, and biogenesis, thereby enhancing mitochondrial function and effectively mitigating H2S-induced biotoxicity. Our research not only elucidates the biotoxicity mechanisms of H2S exposure but also provides valuable insights into potential therapeutic strategies that alleviate or eliminate its toxic effects.

Characterizing multifaceted environmental risks of oil and gas well leakage through soil and well methane and hydrogen sulfide emissions

Oil and gas wells (OGWs) can lead to soil and well emissions of methane (CH4), a potent greenhouse gas, and hydrogen sulfide (H2S), a highly toxic gas, both of which reduce air quality and can cause explosions when emitted into confined spaces. Developments have been occurring over OGWs, posing health and safety risks. However, to our knowledge, previous studies have not conjunctively analyzed well and soil emissions while considering development on or near OGWs. In this paper, we characterize 343 CH4 and H2S emission rate measurements from 67 non-producing (abandoned) and 35 producing (active) OGWs, including 205 measurements from soils surrounding 81 OGWs in Ontario and Quebec. We also provide the first emission rate estimates from an abandoned water and OGW-linked explosion and map OGWs in urban and built-up areas in Ontario and Quebec. We estimate the explosion-linked emissions to be 3,000 g CH4/hour and 7 g H2S/hour. Moreover, we find that 7,264 and 161 OGWs in Ontario and Quebec, respectively, are in urban and built-up areas, with 94% of these wells being abandoned. For the 102 wells we measured, of which 9.7% had H2S detections, we find OGW emission rate ranges of -16 to 47,000 mg CH4/hour and 0.001 to 3,300 mg H2S/hour. Although soil CH4 emissions at a 1-m distance from the wells are most correlated with well emissions, the highest soil emission rate was observed at a 3-m distance, indicating the potential for OGW-related emissions into buildings to occur away from the well. Overall, our multi-faceted measurement dataset provides a basis for conjunctive analysis of the broad range of environmental risks of OGWs to climate, indoor and outdoor air quality, and explosions.

Postbiotics as Antiinflammatory and Immune-Modulating Bioactive Compounds in Metabolic Dysfunction-Associated Steatotic Liver Disease

Postbiotics, defined as products or metabolic byproducts secreted by live bacteria or released after bacterial lysis, are emerging as promising therapeutic agents for metabolic dysfunction-associated steatotic liver disease (MASLD). This review explores the antiinflammatory and immunomodulatory properties of various postbiotics, including exopolysaccharides, lipoteichoic acid, short-chain fatty acids, hydrogen sulfide, polyamines, tryptophan derivatives, and polyphenol metabolites. These compounds have demonstrated potential in mitigating steatotic liver infiltration, reducing inflammation, and slowing fibrosis progression in preclinical studies. Notably, postbiotics exert their beneficial effects by modulating gut microbiota composition, enhancing intestinal barrier function, optimizing lipid metabolism, reducing hepatic inflammation and steatosis, and exhibiting hepatoprotective properties. However, translating these findings into clinical practice requires well-designed trials to validate efficacy and safety, standardize production and characterization, and explore personalized approaches and synergistic effects with other therapeutic modalities. Despite challenges, the unique biological properties of postbiotics, such as enhanced safety compared to probiotics, make them attractive candidates for developing novel nutritional interventions targeting the multifactorial pathogenesis of MASLD. Further research is needed to establish their clinical utility and potential to improve liver and systemic outcomes in this increasingly prevalent condition.

Sargassum Inundations and the Risk of Hypertension Disorders Among Pregnant Women Living in the French Caribbean Island of Martinique

Since 2011, Caribbean territories have experienced massive and repeated sargassum seaweed inundations. Once on shore, sargassum degradation through anaerobic metabolism elicits the release of many noxious molecules, including hydrogen sulfide (H2S) and ammonia (NH3). H2S has been long recognized as a malodorous and highly toxic gas, while chronic exposure has not been extensively explored. Our objective was to assess whether pregnant women exposed to sargassum emissions would be more prone to developing hypertensive disorders compared to unexposed women. We conducted a retrospective study including 3020 pregnant women at the Obstetrics Department of the University Hospital of Martinique between 25 January 2016 and 31 July 2020. Exposure was defined as a distance of less than 2 km between the residence/workplace of the women and the sargassum strandings. Multivariate regression retained age, body mass index, sickle cell disease, primipaternity, gestational diabetes and sargassum emissions exposure as independent predictors of hypertensive events in pregnant women. Jointly with previous studies from our group, this study highlights the deleterious effects of sargassum emissions on human health in individuals chronically exposed to low to moderate H2S concentrations.

Temporal and spatial variation in hydrogen sulfide (H2S) emissions during holopelagic Sargassum spp. decomposition on beaches

BACKGROUND

Since 2011, over 30 tropical Atlantic nations have experienced substantial landings of holopelagic Sargassum spp. Its decomposition results in the production of hydrogen sulfide (H2S), which, in elevated concentrations, can pose a threat to human health. This study aims to enhance our understanding of the temporal and spatial variability in H2S emissions during the decomposition of Sargassum on beaches. The primary objective is to assess potential exposure risks for local populations, tourists, and cleanup workers.

METHODS

H2S levels were monitored using a SENKO sensor (SGTP-H2S; limit of detection 0.1-100 ppm; resolution 0.1 ppm) at four distances from Sargassum accumulation points of (0, 10, 30, and 40 m) in Puerto Morelos, Mexico, during 2022 and 2023.

RESULTS

Elevated concentrations of H2S were detected beneath the Sargassum piles, with 23.5% of readings exceeding 5 ppm and occasional spikes above 100 ppm. Above the piles, 87.3% of the measurements remained below 2 ppm, and the remainder fell between 2.1 and 5.2 ppm. At 10 m from the shoreline, 90% of measurements registered below 0.1 ppm, and the remaining 10% were below 2 ppm. Readings at 30 and 40 m consistently recorded levels below 0.1 ppm. H2S concentrations positively correlated with Sargassum pile height, the temperature beneath the piles, and wind speed.

CONCLUSIONS

Our findings suggest no immediate and significant exposure risk for residents or tourists. However, Sargassum cleanup workers face a higher exposure risk, potentially encountering concentrations above 5 ppm for nearly one-fourth of the working time.

Oxidation of Hydrogen Sulfide to Polysulfide and Thiosulfate by a Carbon Nanozyme: Therapeutic Implications with an Emphasis on Down Syndrome

Hydrogen sulfide (H2 S) is a noxious, potentially poisonous, but necessary gas produced from sulfur metabolism in humans. In Down Syndrome (DS), the production of H2 S is elevated and associated with degraded mitochondrial function. Therefore, removing H2 S from the body as a stable oxide could be an approach to reducing the deleterious effects of H2 S in DS. In this report we describe the catalytic oxidation of hydrogen sulfide (H2 S) to polysulfides (HS2+n - ) and thiosulfate (S2 O3 2- ) by poly(ethylene glycol) hydrophilic carbon clusters (PEG-HCCs) and poly(ethylene glycol) oxidized activated charcoal (PEG-OACs), examples of oxidized carbon nanozymes (OCNs). We show that OCNs oxidize H2 S to polysulfides and S2 O3 2- in a dose-dependent manner. The reaction is dependent on O2 and the presence of quinone groups on the OCNs. In DS donor lymphocytes we found that OCNs increased polysulfide production, proliferation, and afforded protection against additional toxic levels of H2 S compared to untreated DS lymphocytes. Finally, in Dp16 and Ts65DN murine models of DS, we found that OCNs restored osteoclast differentiation. This new action suggests potential facile translation into the clinic for conditions involving excess H2 S exemplified by DS.

Development of CuO/Cu4(OH)6SO4 Nanoparticle Mixtures to Optimize the H2S Adsorption

In this paper, we report the H2S adsorption behavior of a sorbent composed of mixtures of tenorite (CuO) and brochantite [Cu4(OH)6SO4]. These materials are readily prepared through the addition of NaOH(aq) to CuSO4(aq). They can be loaded onto polymer foams to create effective filters that can remove malodorous H2S gas, as evidenced by breakthrough tests. X-ray diffraction shows that the ratio of the two compounds in the mixture can be finely tuned by varying the amount of NaOH(aq) that is added to the reaction mixture. X-ray photoelectron spectroscopy shows that brochantite, like tenorite, has the ability to chemically adsorb H2S. Correlation of the H2S breakthrough data with scanning transmission electron microscopy measurements shows that the most effective sorbents contain nanoscale needle-like particles. These are likely to be formed largely by the tenorite phase. The samples with the greatest H2S adsorption efficacy contained less than 20% tenorite in the mixture, where these particles had the greatest abundance. The application of this sorbent onto porous substrates to create effective filters, along with the synthetic ease of its production, could allow this methodology to find use in a number of areas where H2S poses a problem. This could include areas where protective clothing is required to adsorb the gas from environments where there is a high level of H2S, for example, in wastewater treatment plants, oil and gas wells, or in the medical sector, where it could be deployed as filter media.

Respiratory and nervous system effects of a hydrogen sulfide crisis in Carson, California

BACKGROUND

In October 2021, many residents in Carson, California experienced malodors, headaches, and respiratory symptoms. Hydrogen sulfide (H2S), a toxic odorous gas, was measured in Carson at concentrations up to 7000 parts per billion (ppb) and remained above California's acute air quality standard of 30 ppb for about a month. Research on how low- and medium-level H2S exposure affects the respiratory and nervous systems has yielded conflicting results, and few studies have examined the effects of subacute H2S exposure.

METHODS

We calculated daily rates of emergency department (ED) visits with various respiratory and nervous systems diagnosis codes in Carson area ZIP codes (≤6 km from event's epicenter) and in Los Angeles County ZIP codes >15 km from event's epicenter (control area). Using controlled interrupted time series, we compared ED visit rates during the month of the H2S crisis in Carson to the predicted rates had the incident not occurred, based on 2018-2021 ED trends, and controlling for ED visit rate changes in the control area.

RESULTS

We observed a 24 % increase in ED visit rate for all respiratory system diseases (rate ratio = 1.24, 95 % CI: 1.16, 1.32), a 38 % increase for asthma (RR = 1.38, 95 % CI: 1.26, 1.50), a 26 % increase for acute upper respiratory infections (RR = 1.26, 95 % CI: 1.13, 1.38), a 21 % increase for dizziness (RR = 1.21, 95 % CI: 1.04, 1.38), and a 25 % increase for migraines and headaches (RR = 1.25, 95 % CI: 1.13, 1.36) in the Carson area during the first month of the H2S event compared to the expected rates.

CONCLUSIONS

This H2S crisis was associated with increased ED visit rates for multiple respiratory and nervous system outcomes. Reducing H2S exposure and improving to response during H2S episodes may improve public health.

Exposure to low levels of hydrogen sulphide and its impact on chronic obstructive pulmonary disease and lung function in the geothermal area of Mt. Amiata in Italy: The cross-sectional InVETTA study

BACKGROUND

The geothermal power plants for electricity production currently active in Italy are all located in Mt. Amiata area in the Tuscany region. A cross-sectional survey was conducted in the framework of the regional project "InVETTA-Biomonitoring Survey and Epidemiological Evaluations for the Protection of Health in the Amiata Territories", using objective measures of lung function to investigate the role of hydrogen sulphide (H2S) in affecting the respiratory health of the population living in this area.

METHODS

2018 adults aged 18-70 were enrolled during 2017-2019. Home and workplace addresses of participants were geocoded. Dispersion modelling was used to evaluate the spatial variability of exposure to H2S from the geothermal power plants' emissions. We estimated average long-term historical exposure to H2S and more recent exposure indicators. Chronic Obstructive Pulmonary Disease (COPD) was defined according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Multivariable logistic regressions were performed to investigate associations between outcome and exposure.

RESULTS

Our findings did not showed any evidence of an association between increasing H2S exposure and lung function impairments. Some risk reductions were observed: a -32.8% (p = 0.003) for FEV1<80% and a -51.7% (p = 0.001) risk decrease for FVC<80% were associated with interquartile increase (13.8 μg/m3) of H2S levels.

CONCLUSION

Our study provides no evidence that chronic exposure to low levels of H2S is associated with decrements in pulmonary function, suggesting that ambient H2S exposure may benefit lung function.

Low level exposure to hydrogen sulfide: a review of emissions, community exposure, health effects, and exposure guidelines

Hydrogen sulfide (H2S) is a toxic gas that is well-known for its acute health risks in occupational settings, but less is known about effects of chronic and low-level exposures. This critical review investigates toxicological and experimental studies, exposure sources, standards, and epidemiological studies pertaining to chronic exposure to H2S from both natural and anthropogenic sources. H2S releases, while poorly documented, appear to have increased in recent years from oil and gas and possibly other facilities. Chronic exposures below 10 ppm have long been associated with odor aversion, ocular, nasal, respiratory and neurological effects. However, exposure to much lower levels, below 0.03 ppm (30 ppb), has been associated with increased prevalence of neurological effects, and increments below 0.001 ppm (1 ppb) in H2S concentrations have been associated with ocular, nasal, and respiratory effects. Many of the studies in the epidemiological literature are limited by exposure measurement error, co-pollutant exposures and potential confounding, small sample size, and concerns of representativeness, and studies have yet to consider vulnerable populations. Long-term community-based studies are needed to confirm the low concentration findings and to refine exposure guidelines. Revised guidelines that incorporate both short- and long-term limits are needed to protect communities, especially sensitive populations living near H2S sources.

Health impact of natural gas emission at Cava dei Selci residential zone (metropolitan city of Rome, Italy)

Natural gas hazard was assessed at Cava dei Selci, a residential neighbourhood of Marino (Rome) by a joint study of gas emissions and related health problems. Here a densely urbanized zone with 4000 residents surrounds a dangerous natural gas discharge where, along the years, dozens of animals were killed by the gas. Gas originates from Colli Albani volcano and consists mostly of CO₂ with ~ 1 vol% of H₂S. In recent years, several gas-related accidents occurred in the urbanized zone (gas blowouts and road collapses). Some houses were evacuated because of hazardous indoor air gas concentration. Gas hazard was assessed by soil CO₂ flux and concentration surveys and indoor and outdoor air CO₂ and H₂S concentration measurements. Open fields and house gardens release a high quantity of CO₂ (32.23 tonnes * day^-1). Inside most houses, CO₂ air concentration exceeds 0.1 vol%, the acceptable long-term exposure range. In several houses both CO₂ and H₂S exceed the IDLH level (Immediately Dangerous to Life and Health). An epidemiological cohort study was carried out on the residents of two Cava dei Selci zones with high (zone A) and medium (zone B) gas hazard exposure, using the rest of Marino as reference zone. We found excess mortality and emergency room visits (ERV) related to high exposure to CO₂ and H₂S; in particular, an increased risk of mortality and ERV for diseases of central nervous system (HR 1.57, 95% CI 0.76-3.25 and HR 5.82, 95% CI 1.27-26.56, respectively) was found among men living in zone A.

Occupational Risk Assessment in Landfills: Research Outcomes from Italy

Industrial production has brought increased wellbeing in the last years, but the amount of solid waste has undoubtedly increased. Thus, open dumpsites and landfills have been created throughout the world, with serious impacts on the environment and public health. In such a context, occupational health and safety (OHS) issues related to workers that have to deal with landfill characterization or management have not been considered sufficiently. To reduce such a research gap, in 2019 a research project started in Italy on OHS risk assessment in landfills. In fact, in such facilities, workers can be subjected to direct contact with the polluted environment and might not be completely aware of the entity and type of pollution (e.g., in open dumpsites). Starting with the analysis of INAIL data on accidents at work which occurred in Italy during the period 2008–2019, a specific risk analysis was carried out with the goal of defining risk determinants and profiles by means of K-means cluster analysis. Such an analysis allowed us to recognize the use of work equipment and the work environment as the main determinants of the accidents on the one hand, and the “driver of the excavator” as the most risky activity on the other. The achieved results take a step forward towards the characterization of occupational health and safety issues in landfills. Accordingly, the research outcomes represent a basis on which to address further research work in this field.

Analysis of the Interior Microclimate in Art Nouveau Heritage Buildings for the Protection of Exhibits and Human Health

Poor air quality inside museums can have a double effect; on the one hand, influencing the integrity of the exhibits and on the other hand, endangering the health of employees and visitors. Both components can be very sensitive to the influence of the internal microclimate, therefore careful monitoring of the physical parameters and pollutants is required in order to maintain them within strict limits and thus to reduce the hazards that can be induced. The current study considers the determination and analysis of 15 indicators of the internal microclimate in an Art Nouveau museum built at the beginning of the 20th century in the Municipality of Oradea, Romania. The monitoring spanned a period of seven months, between September 2021 and March 2022, targeting three rooms of the museum with different characteristics and containing exhibits with a high degree of fragility. The results show that, although there are numerous indicators that have exceeded the thresholds induced by international standards, the possible negative impact on the exhibits and/or on human health remains moderate. This is due to the fact that, most of the time, exceeding the permitted limits are small or only sporadic, the values quickly returning to the permitted limits. Thus, only 22 of the 212 days of monitoring recorded marginal conditions regarding the quality of the indoor air, the rest having acceptable and good conditions. To improve the indoor conditions, a more careful management is needed, especially regarding the values of temperature, humidity, particulate matters, natural and artificial light, volatile organic compounds (VOC) and formaldehyde (HCHO), which during the measurements recorded high values that fluctuated in a wide spectrum. The obtained results can represent the basis for the development and implementation of long-term strategies for stabilizing the microclimatic conditions in the museum in order to preserve the exhibits preventively and to ensure a clean and safe environment for people.

Effect of Bimetallic-Activated Carbon Impregnation on Adsorption-Desorption Performance for Hydrogen Sulfide (H2S) Capture

This study reports on the impregnation of bi-metallic adsorbents based on commercial coconut activated carbon (CAC), surface-modified with metal acetate (ZnAc₂), metal oxide (ZnO and TiO₂), and the basic compound potassium hydroxide (KOH). The morphology of the adsorbents was then characterized with SEM-EDX, the microporosity was determined using Brunauer-Emmett-Teller (BET) analysis, the thermal stability was investigated via thermogravity analysis (TGA), and functional group analysis was undertaken with Fourier-transform infrared (FTIR) spectroscopy. These modified adsorbents were subjected to a real adsorption test for H₂S capture using a 1 L adsorber with 5000 ppm H₂S balanced for N₂, with temperature and pressure maintained at an ambient condition. Adsorption-desorption was carried out in three cycles with the blower temperature varied from 50 °C to 150 °C as the desorption condition. Characterization results revealed that the impregnated solution homogeneously covered the adsorbent surface, effecting the morphology and properties. Based on this study, it was found that ZnAc₂/TiO₂/CAC_DCM showed a significant increase in adsorption capacity with the different temperatures applied for the desorption in the second cycle: 1.67 mg H₂S/g at 50 °C, 1.84 mg H₂S/g at 100 °C, and 1.96 mg H₂S/g at 150 °C. ZnAc₂/ZnO/CAC_DCM seemed to produce the lowest percentage of degradation in the three cycles for all the temperatures used in the adsorption-desorption process. Therefore, ZnAc₂/ZnO/CAC_DCM has the potential to be used and commercialized for biogas purification for H₂S removal.

Risk of preeclampsia among women living in coastal areas impacted by sargassum strandings on the French Caribbean island of Martinique

OBJECTIVE

To investigate preeclampsia risk of pregnant women living in coastal areas regularly impacted by massive sargassum strandings.

DESIGN

Retrospective cohort study SETTINGS AND POPULATION: Pregnant women (n = 3020), seen at the University Hospital of Martinique, were included between 25/01/2016 and 31/07/2020.

METHODS

Patient records were retrospectively reviewed. Distance from coastline sargassum stranding sites was characterized as follows: < 500 m, 500 m-2 km, > 2 km.

MAIN OUTCOME MEASURES

Primary endpoint was occurrence of preeclampsia. Secondary endpoint was time to preeclampsia defined as the number of weeks free of preeclampsia between the 20th and 37th week of amenorrhea.

RESULTS

Time to preeclampsia onset was significantly shorter in women living in the ≤ 2 km range (mean survival time 32 ± 1 amenorrhea weeks) compared to those beyond 2 km (mean survival time 35 ± 1 amenorrhea weeks, p = 0.037).

CONCLUSION

Along with traditional risk factors, environmental exposure to sargassum strandings might potentially trigger early onset of preeclampsia.

Environmental monitoring and health assessment in an industrial town in central India: A cross-sectional study protocol

Background

Textile industry has been widely implicated in environmental pollution. The health effects of residing near manufacturing industries are not well documented in India, especially in central India. Hence, a cross-sectional environmental monitoring and health assessment study was initiated as per directions of the local authorities.

Methods

Comprehensive exposure data about the concentrations of relevant pollutants in the ambient air and ground water samples in the study area will be collected over one year. Using stratified random sampling, 3003 apparently healthy adults will be selected from the study area. Sociodemographic and anthropometric information, relevant medical and family history, and investigations including spirometry, electrocardiogram, neurobehavioral tests, and laboratory investigations (complete blood count, lipid profile and random blood glucose) will be conducted. Finally Iodine azide test and heavy metal level detection in urine and blood samples respectively will be conducted in a subset of selected participants to assess individual pollution exposure. Ethics approval has been obtained from the Institutional Ethics Committee of the National Institute for Research in Environmental Health (No: NIREH/IEC-7-II/1027, dated 07/01/2021).

Discussion

This manuscript describes the protocol for a multi-disciplinary study that aims to conduct environmental monitoring and health assessment in residential areas near viscose rayon and associated chemical manufacturing industries. Although India is the second largest manufacturer of rayon, next only to China, and viscose rayon manufacturing has been documented to be a source of multiple toxic pollutants, there is a lack of comprehensive information about the health effects of residing near such manufacturing units in India. Therefore implementing this study protocol will aid in filling in this knowledge gap.

Progress and perspective on hydrogen sulfide donors and their biomedical applications

Following the discovery of nitric oxide (NO) and carbon monoxide (CO), hydrogen sulfide (H₂ S) has been identified as the third gasotransmitter in humans. Increasing evidence have shown that H₂ S is of preventive or therapeutic effects on diverse pathological complications. As a consequence, it is of great significance to develop suitable approaches of H₂ S-based therapeutics for biomedical applications. H₂ S-releasing agents (H₂ S donors) play important roles in exploring and understanding the physiological functions of H₂ S. More importantly, accumulating studies have validated the theranostic potential of H₂ S donors in extensive repertoires of in vitro and in vivo disease models. Thus, it is imperative to summarize and update the literatures in this field. In this review, first, the background of H₂ S on its chemical and biological aspects is concisely introduced. Second, the studies regarding the H₂ S-releasing compounds are categorized and described, and accordingly, their H₂ S-donating mechanisms, biological applications, and therapeutic values are also comprehensively delineated and discussed. Necessary comparisons between related H₂ S donors are presented, and the drawbacks of many typical H₂ S donors are analyzed and revealed. Finally, several critical challenges encountered in the development of multifunctional H₂ S donors are discussed, and the direction of their future development as well as their biomedical applications is proposed. We expect that this review will reach extensive audiences across multiple disciplines and promote the innovation of H₂ S biomedicine.

Methane and hydrogen sulfide emissions from abandoned, active, and marginally producing oil and gas wells in Ontario, Canada

Abandoned, active, and marginally producing (producing <1700 m³/day of natural gas or <1.6 m³/day of oil) oil and gas (O&G) wells emit methane (CH₄), a potent greenhouse gas, and hydrogen sulfide (H₂S), a highly toxic gas, but measurements to quantify these emission rates are limited or lacking. Here, we conduct 85 measurements of CH₄ and H₂S emission rates from 63 abandoned, active and marginally producing gas wells and a wetland area overlying a possible undocumented well in Ontario, the Canadian province with the longest history of O&G development. Our measurements show that abandoned wells emitting H₂S are some of the highest CH₄ emitters (average = 16600 mg CH₄/h/well), followed by abandoned unplugged and marginally producing wells. Abandoned plugged (average = 2100 mg CH₄/h/well) and producing (average = 6800 mg CH₄/h/well) wells are the lowest CH₄ emitters. Compared to inventory estimates, CH₄ emissions from marginally producing and active wells in Ontario are underestimated by a factor of 2.1, and emissions from abandoned plugged wells are underestimated by a factor of 920. H₂S emissions, currently not included in the Canadian Air Pollutant Emissions Inventory, average at 160 mg H₂S/h/well. Our findings highlight the importance of conducting measurements from all types of oil and gas wells including H₂S emitting wells to understand H₂S and CH₄ emissions and develop policies to reduce greenhouse gas emissions, improve air quality, and protect human and ecosystem health.

Quantitative proteomics reveals tissue-specific toxic mechanisms for acute hydrogen sulfide-induced injury of diverse organs in pig

Hydrogen sulfide (H₂S) is a highly toxic gas in many environmental and occupational places. It can induce multiple organ injuries particularly in lung, trachea and liver, but the relevant mechanisms remain poorly understood. In this study, we used a TMT-based discovery proteomics to identify key proteins and correlated molecular pathways involved in the pathogenesis of acute H₂S-induced toxicity in porcine lung, trachea and liver tissues. Pigs were subjected to acute inhalation exposure of up to 250 ppm of H₂S for 5 h for the first time. Changes in hematology and biochemical indexes, serum inflammatory cytokines and histopathology demonstrated that acute H₂S exposure induced organs inflammatory injury and dysfunction in the porcine lung, trachea and liver. The proteomic data showed 51, 99 and 84 proteins that were significantly altered in lung, trachea and liver, respectively. Gene ontology (GO) annotation, KEGG pathway and protein-protein interaction (PPI) network analysis revealed that acute H₂S exposure affected the three organs via different mechanisms that were relatively similar between lung and trachea. Further analysis showed that acute H₂S exposure caused inflammatory damages in the porcine lung and trachea through activating complement and coagulation cascades, and regulating the hyaluronan metabolic process. Whereas antigen presentation was found in the lung but oxidative stress and cell apoptosis was observed exclusively in the trachea. In the liver, an induced dysfunction was associated with protein processing in the endoplasmic reticulum and lipid metabolism. Further validation of some H₂S responsive proteins using western blotting indicated that our proteomics data were highly reliable. Collectively, these findings provide insight into toxic molecular mechanisms that could potentially be targeted for therapeutic intervention for acute H₂S intoxication.

Facile Fabrication of ZnO-ZnFe2O4 Hollow Nanostructure by a One-Needle Syringe Electrospinning Method for a High-Selective H2S Gas Sensor

Herein, a facile fabrication process of ZnO-ZnFe₂O₄ hollow nanofibers through one-needle syringe electrospinning and the following calcination process is presented. The various compositions of the ZnO-ZnFe₂O₄ nanofibers are simply created by controlling the metal precursor ratios of Zn and Fe. Moreover, the different diffusion rates of the metal oxides and metal precursors generate a hollow nanostructure during calcination. The hollow structure of the ZnO-ZnFe₂O₄ enables an enlarged surface area and increased gas sensing sites. In addition, the interface of ZnO and ZnFe₂O₄ forms a p-n junction to improve gas response and to lower operation temperature. The optimized ZnO-ZnFe₂O₄ has shown good H₂S gas sensing properties of 84.5 (S = R_a/R_g) at 10 ppm at 250 °C with excellent selectivity. This study shows the good potential of p-n junction ZnO-ZnFe₂O₄ on H₂S detection and affords a promising sensor design for a high-performance gas sensor.

H2S exposure induces cell death in the broiler thymus via the ROS-initiated JNK/MST1/FOXO1 pathway

Hydrogen sulfide (H₂S) is a common toxic gas in chicken houses that endangers the health of poultry. Harbin has a cold climate in winter, and the conflict between heat preservation and ventilation in poultry houses is obvious. In this study, we investigated the H₂S content in chicken houses during winter in Harbin and found that the H₂S concentration exceeded the national standard in individual chicken houses. Then, a model of H₂S exposure was established in an environmental simulation chamber. We also developed a NaHS exposure model of chicken peripheral blood lymphocytes in vitro. Proteomics analysis was used to reveal the toxicology of thymus injury in broilers, the FOXO signaling pathway was determined to be significantly enriched, ROS bursts and JNK/MST1/FOXO1 pathway activation induced by H₂S exposure were detected, and ROS played an important switch role in the JNK/MST1/FOXO1 pathway. In addition, H₂S exposure-induced thymus cell death involved immune dysregulation. Overall, the present study adds data for H₂S contents in chicken houses, provides new findings for the mechanism of H₂S poisoning and reveals a new regulatory pathway in immune injury.

Diagnosis Model of Hydrogen Sulfide Poisoning Based on Support Vector Machine

Introduction:

Hydrogen sulfide (H2S) is a lethal environmental and industrial poison. The mortality rate of occupational acute H2S poisoning reported in China is 23.1% ~ 50%. Due to the huge amount of information on metabolomics changes after body poisoning, it is important to use intelligent algorithms to mine multivariate interactions.

Methods:

This paper first uses GC-MS metabolomics to detect changes in the urine components of the poisoned group and control rats to form a metabolic dataset, and then uses the SVM classification algorithm in machine learning to train the hydrogen sulfide poisoning training dataset to obtain a classification recognition model. A batch of rats (n = 15) was randomly selected and exposed to 20 ppm H2S gas for 40 days (twice morning and evening, 1 hour each exposure) to prepare a chronic H2S rat poisoning model. The other rats (n = 15) were exposed to the same volume of air and 0 ppm hydrogen sulfide gas as the control group. The treated urine samples were tested using a GC-MS.

Results:

The method locates the optimal parameters of SVM, which improves the accuracy of SVM classification to 100%. This paper uses the information to gain an attribute evaluation method to screen out the top 6 biomarkers that contribute to the predicted category (Glycerol, -Hydroxybutyric acid, arabinofuranose, Pentitol, L-Tyrosine, L-Proline).

Conclusion:

The SVM diagnostic model of hydrogen sulfide poisoning constructed in this work has training time and prediction accuracy; it has achieved excellent results and provided an intelligent decision-making method for the diagnosis of hydrogen sulfide poisoning.

A regenerable N-rich hierarchical porous carbon synthesized from waste biomass for H2S removal at room temperature

In this study, N-rich hierarchical porous carbons (NPCs) were synthesized via one step strategy from cypress sawdust with carbon nitride (CN) loading and K₂CO₃ activation. NPCs exhibited excellent performance for H₂S removal with the sulfur capacity up to 426.2 mg/g at room temperature. It was much higher than 12.5 mg/g of porous carbon (PC) which was only activated by K₂CO₃. The NPCs with CN loading showed hierarchical porous structure with micropores and mesopores volume up to 0.434 and 0.597 cm³/g, respectively. Moreover, NPCs had high N contents (up to 12.37 wt%) and high relative contents of pyridinic N and pyrrolic N within 76.61-84.37%, which were identified as active sites for H₂S adsorption by density functional theory calculation, enhancing H₂S removal. The formation mechanism of NPCs was investigated by TG-FTIR, suggesting that CN pyrolysis result in hierarchical porous structure and rich N-containing functional groups by gradually releasing H₂O, CO₂ and NH₃. Moreover, the NPCs showed high regeneration ability, remaining 86.6% of the initial sulfur capacity after five regeneration cycles, and sulfur (S) was the main desulfurization product (H₂S + O₂ → S + H₂O). The results demonstrate that NPCs are promising catalysts to remove H₂S efficiently with low cost and high reusability.

Pre-exposure to hydrogen sulfide modulates the innate inflammatory response to organic dust

Animal production units produce and store many contaminants on-site, including organic dust (OD) and hydrogen sulfide (H₂S). Workers in these settings report various respiratory disease symptoms. Both OD and H₂S have shown to induce lung inflammation. However, impact of co-exposure to both H₂S and OD has not been investigated. Therefore, we tested a hypothesis that pre-exposure to H₂S modulates the innate inflammatory response of the lungs to organic dust. In a mouse model of H₂S and organic dust extract (ODE) exposure, we assessed lung inflammation quantitatively. We exposed human airway epithelial and monocytic cells to medium or H₂S alone or H₂S followed by ODE and measured cell viability, oxidative stress, and other markers of inflammation. Exposure to 10 ppm H₂S followed by ODE increased the lavage fluid leukocytes. However, exposure to 10 ppm H₂S alone resulted in changes in tight junction proteins, an increase in mRNA levels of tlr2 and tlr4 as well as ncf1, ncf4, hif1α, and nrf2. H₂S alone or H₂S and ODE exposure decreased cell viability and increased reactive nitrogen species production. ODE exposure increased the transcripts of tlr2 and tlr4 in both in vitro and in vivo models, whereas increased nfkbp65 transcripts following exposure to ODE and H₂S was seen only in in vitro model. H₂S alone and H₂S followed by ODE exposure increased the levels of IL-1β. We conclude that pre-exposure to H₂S modulates lung innate inflammatory response to ODE.

Proteomics analysis of lung reveals inflammation and cell death induced by atmospheric H2S exposure in pig

Hydrogen sulfide (H₂S) is a popular toxic environmental gas and industrial pollutant, which can be harmful to multiple organ systems of both human and livestock, especially to the respiratory system. However, the injury mechanism of H₂S exposure to lung remains poorly understood. In this study, pig lung was selected as a H₂S exposure model for the first time. We first examined the histological damage and the mRNA expression of pro-inflammatory genes of lung in pigs exposed to H₂S. Histopathology change and increased mRNA level of pro-inflammatory cytokines demonstrated that H₂S exposure indeed induced inflammatory injury in the porcine lung. We then performed TMT-based quantitative proteomics analysis to probe the injury molecular mechanism. The proteomics results showed that 526 proteins have significant changes in abundance between control and H₂S treated swine. Further validation analysis of some H₂S responsive proteins using both Real-time quantitative PCR and western blotting demonstrated that proteomics data are reliable. KEGG pathway analysis revealed that these proteins were involved in antigen processing and presentation, complement and coagulation cascade, IL-17 signaling pathway, ferroptosis and necroptosis. Our data suggest that H₂S exposure induced immune suppression, inflammatory response and cell death. These findings provide a new insight into the complexity mechanisms of H₂S induced lung injury, and offer therapeutic potential as drug targets with a view towards curing the intoxication caused by H₂S.

Hydrogen sulfide and cardiovascular disease: Doubts, clues, and interpretation difficulties from studies in geothermal areas

Hydrogen sulfide (H₂S) represents one of the main pollutants originating from both geologic phenomena such as volcanoes, geysers, fumaroles and hot springs, and geothermal plants that produce heat and electricity. Many increasing data suggest that H₂S retains a variety of biological properties, and modulates many pathways related to cardiovascular pathophysiology although its role as beneficial/adverse determinant on cardiovascular disease (CVD) is not clearly established. In this review, the current knowledge on the association between H₂S exposure and risk of CVD in geothermal areas has been examined. The few epidemiological studies carried out in geothermal areas suggest, in some cases, a protective role of H₂S towards CVD, while in others a positive association between exposure to H₂S and increased incidence of CVD. Most of the studies have an ecological design that does not allow to produce evidence to support a causal relationship and also often lack for an adequate adjustment for individual CVD risk factors. The review has also considered the potential role of two other aspects not sufficiently explored in this relationship: the production of endogenous H₂S that is a gasotransmitter producing beneficial effects on cardiovascular function at low concentration and the intake of H₂S-releasing drugs for the treatment of patients affected by hypertension, inflammatory diseases, and CVD. Thus, a threshold effect of H₂S and the shift of action as beneficial/adverse determinant given by the synergy of exogenous exposure and endogenous production cannot be excluded. In this complex scenario, an effort is warranted in the future to include a more comprehensive evaluation of risk for CVD in relation to H₂S emissions, especially in geothermal areas.

Omega-3 polyunsaturated fatty acids alleviate hydrogen sulfide-induced blood-testis barrier disruption in the testes of adult mice

Hydrogen sulfide (H₂S), a gaseous intracellular signal transducer, participates in multiple physiological and pathological conditions, including reproductive conditions, and disrupts spermatogenesis. The blood-testis barrier (BTB) plays a vital role in spermatogenesis. However, the effect of H₂S on the BTB and the underlying mechanism remain unclear. Herein, we examined the effect of H₂S and omega-3 polyunsaturated fatty acids (ω-3 PUFAs) on the BTB and testicular functions. ICR male mice were randomly divided into the following groups: control, H₂S exposure, and H₂S exposure with ω-3 PUFAs intervention. The sperm parameters (sperm concentration and sperm motility) declined in the H₂S group and improved in the ω-3 intervention group. BTB integrity was severely disrupted by H₂S, and the BTB-related gene levels (ZO-1, Occludin, Claudin 11) decreased; ω-3 supplementation could alleviate BTB disruption by upregulating BTB-related genes, and TM4 Sertoli cells had a similar trend in vitro. p38 MAPK phosphorylation was upregulated in the Na₂S treatment group and downregulated after ω-3 cotreatment. These findings suggest that H₂S can impair the BTB and that ω-3 PUFAs supplementation can attenuate H₂S toxicity in the male reproductive system. Our study elucidated the relationship between a gasotransmitter (H₂S) and the BTB and identified the potential therapeutic effect of ω-3 PUFAs.

Effects of drinking natural hydrogen sulfide (H2S) waters: a systematic review of in vivo animal studies

Natural waters containing originally hydrogen sulfide (H2S) gas with an S2-level at least 1 mg/L are classified as "sulfur waters" or "hydrogen sulfide waters." This systematic review aimed to evaluate in vivo experimental studies investigating the biological effects of natural H2S water drinking in healthy or with disease model laboratory animals. A comprehensive databases search (PubMed, Embase, Web of Science, and Google Scholar) was performed and PICOS criteria were used to assess eligibility. All relevant studies were identified, screened, and examined. The qualitative assessment was performed with the help of the SYRCLE Risk of Bias tool. A total of nine articles were included. The extracted data showed that ad libitum drinking of such waters by rats and mice exert beneficial effects on animal model of diabetes and glucose metabolism plus protective effects on diabetic cardiac, testicular, and nephrological complications as shown biochemically, histopathologically, and bio-molecularly. Additional effects were gastroprotection, antioxidant effects and improvement of intestinal physiology in healthy animals, reduction in general signs of murine model of colitis in mice, improvement in lipid metabolism and lipid-lowering effect, and positive interference with the enterohepatic cycle of the bile acids and biliary functions in hyperlipidemic rats. This systematic review provides preliminary insights into the "biological truth" about natural H2S waters and partly elucidates their potential therapeutic role in balneology and health resort medicine. However, it should be kept in mind that the retrieved preclinical data cannot be directly extrapolated to humans. Additionally, most of the included studies were rated for unclear risk of bias across all categories except random allocation, reflecting very poor reporting of methodological details. These limitations should be addressed when planning similar studies in the future. The question "can traditional hydropinic therapies or drinking cures with H2S waters at natural sulfur water spas/health resorts or natural (even artificial) H2S water consumption at home exert similar effects in humans?" remains to be clarified by clinical trials.

Health effects associated with short-term exposure to hydrogen sulfide from geothermal power plants: a case-crossover study in the geothermal areas in Tuscany

OBJECTIVE

Thirty-four geothermal power plants for the production of electricity are currently active in the geothermal areas in Tuscany. The present study aimed to investigate the association between short-term exposure to hydrogen sulfide (H₂S) and acute health outcomes.

METHODS

This study used individual data on non-accidental, cardiovascular and respiratory mortality, urgent hospital admissions (HA) and emergency department (ED) visits for cardiorespiratory diseases occurring from 2000 to 2017. All cases were georeferenced and matched to daily H₂S data, derived from 18 monitoring sites. A case-crossover design following the matched pair interval approach was applied and conditional logistic regression models were fitted to estimate odds ratios and their 90% confidence intervals, adjusting for a set of time-dependent variables, such as influenza epidemics, holidays and temperature.

RESULTS

A total of 8054 deaths, 30,527 HA and 15,263 ED visits occurred. Mortality for non-accidental (OR = 1.11, 90% CI 1.02-1.22) and cardiovascular causes (OR = 1.22, 90% CI 1.03-1.44) were associated with an increase of 10 µg/m³ of H₂S daily levels only among men. Hospital admissions for respiratory diseases were positively associated with H₂S exposure: OR = 1.11 (90% CI 1.00-1.22) among women. No associations were observed in ED visits analyses.

CONCLUSIONS

In this case-crossover study in the Tuscan geothermal areas, short-term exposure to H₂S was weakly associated with some mortality and morbidity outcomes. Our findings did not show a clear pattern as the results were not homogeneous between mortality and morbidity data or between men and women.

Evaluation of antioxidant status and oxidative stress markers in thermal sulfurous springs residents

Sulfurous springs have been traditionally used in medical treatment for different purposes. These beneficial effects of sulfurous water have been attributed to the presence of sulfurous compounds mainly in the form of hydrogen sulfide (H₂S). The purpose of the present study is to explore the effects of long-term exposure to sulfurous springs on oxidative stress and antioxidant biomarkers responses in individuals who lived nearby the sulfurous springs. The studied area was Al- Hammah sulfurous springs, which is located in the northern part of the Jordan Rift Valley and host many sulfurous springs. Residents in sulfurous springs area are continuously exposed to water and gases emission more than the overall population. We have found that the sulphate levels were 7 times higher in sulfurous springs water samples than control water samples. The majority of the volunteers involved in the present study were more than ten years long residence and lived in range distance between one to five kilometers (less than 3 miles) away from main sulfurous spring, and visited the sulfurous spring at least once a month. We did not find any noticeable symptoms in sulfur spring residents such as headaches, nausea, breathing problems. The total oxidative stress (TOS) and oxidative stress index (OSI) in sulfurous spring residents were lower than control individuals. The total antioxidant capacity (TAC) and total nitric oxide (NO_X) levels were higher in sulfurous spring residents compared to control group. Furthermore, we have highlighted that living nearby the sulfurous springs does not affect oxygen saturation levels (SPO₂) or heart pulse rate . These findings suggest that long-term exposure to sulfurous springs boost the antioxidant capacity and reduce oxidative stress levels in the human body. Hence, visiting sulfurous springs can act as natural remedies to diminish oxidative stress as they show promising potential in several-oxidative stress-related diseases treatment.

Emissions of ammonia and hydrogen sulfide from typical dairy barns in central China and major factors influencing the emissions

There are few studies on the concentrations and emission characteristics of ammonia (NH₃) and hydrogen sulfide (H₂S) from Chinese dairy farms. The purpose of this study was to calculate the emission rates of NH₃ and H₂S during summer and to investigate influencing factors for NH₃ and H₂S emissions from typical dairy barns in central China. Eleven dairy barns with open walls and double-slope bell tower roofs from three dairy farms were studied. Five different locations in each barn were sampled both near the floor and at 1.5 m above the floor. Concentrations of NH₃ and H₂S were measured using the Nessler’s reagent spectrophotometry method and the methylene blue spectrophotometric method, respectively. NH₃ concentrations varied between 0.58 and 4.76 mg/m³ with the average of 1.54 mg/m³, while H₂S concentrations ranged from 0.024 to 0.151 mg/m³ with the average of 0.092 mg/m³. The concentrations of NH₃ and H₂S were higher during the day than at night, and were higher near the ground than at the height of 1.5 m, and were higher in the manure area than in other areas. NH₃ and H₂S concentrations in the barns were significantly correlated with nitrogen and sulfur contents in feed and manure (P < 0.05), and with temperature inside the barns (P < 0.05). Calculated emission rates of NH₃ ranged from 13.8 to 41.3 g NH₃/(AU·d), while calculated emission rates of H₂S ranged from 0.15 to 0.46 g H₂S/(AU·d). These results will serve as a starting point for a national inventory of NH₃ and H₂S for the Chinese dairy industry.

A review on the removal of hydrogen sulfide from biogas by adsorption using sorbents derived from waste

Biogas is a vital renewable energy source that could play an effective role in fulfilling the world’s energy demand, not only in heat and power generation but also as a vehicle fuel in the future. Unfortunately, due to impurities, biogas requires a series of upgrading steps, which affects its economics and sustainability. Hydrogen sulfide (H2S) is one of the impurities that economically and environmentally hinder the biogas utilization as a source of energy. H2S removal from biogas using different technologies was extensively studied and established. One of such technology is adsorption. Adsorption by solid sorbents is considered as a suitable removal technique for toxic gases such as H2S because of its simplicity, easy handling, and environmental friendly sorbents. In this review, the utilization of waste material-based sorbent for H2S removal was appraised. Other gaseous components of biogas such as siloxanes, CO2, etc., are out of the scope of this work. The potential and effectiveness of the waste-derived sorbents, either raw waste or modified waste, were summarized in terms of its characteristics, suitability, and sustainability. The review provides an insightful analysis of different types of wastes such as sewage sludge, food waste, forestry waste, fly ash, and industrial wastes as an alternative to commercial adsorbents to adsorb H2S gas. Based on the analysis, it was concluded that if these sorbents are to be successfully commercialized, its economic analysis, regeneration conditions, and potential utilization of the spent sorbents has to be further exploited. Nevertheless, there is a great prospectus in the future for these waste materials to be utilized as sorbents for H2S removal.

H2S promotes a glycometabolism disorder by disturbing the Th1/Th2 balance during LPS-induced inflammation in the skeletal muscles of chickens

Hydrogen sulfide (H₂S) is a common environmental pollutant. In humans, H₂S enters the body and is transported to different tissues and organs, inducing various types of damage such as chronic inflammatory reactions. Glucose metabolism disorders have been shown to be closely associated with chronic inflammation. The goal of the present study was to investigate the effects and mechanisms of H₂S on glycometabolism disorders and chronic inflammatory responses. A chronic inflammation model in the skeletal muscles of chickens was induced using lipopolysaccharide (LPS), after which the animals were exposed to exogenous H₂S. Subsequently, the glucose metabolism and the pathways associated with chronic inflammation were analyzed. The pathological analysis showed that significant inflammatory injury to skeletal muscles occurred after animals exposed to H₂S. The Th1/Th2 ratio imbalance was exacerbated after exposure to H₂S with IFNγ downregulated and IL-1, IL-4, and IL-6 upregulated. In addition, the level of IκBα was suppressed and induced the expression of NF-κB, significantly activating the inflammatory pathway, while the expression of heat shock proteins was elevated. In addition, glucose metabolism factors were analyzed. IRS1 phosphorylation was inhibited in animals exposed to H₂S, and the expression of insulin-like growth factor (IGF) signaling pathway-related factors was upregulated to promote insulin resistance, causing glucose metabolism disorders. The results of this study revealed that H₂S can trigger changes in the ratio of Th1/Th2 to produce more proinflammatory cytokines that disturb the insulin signaling pathway, causing glycometabolism disorders during the inflammatory response in the skeletal muscles of chickens.

Health effects associated with chronic exposure to low-level hydrogen sulfide from geothermoelectric power plants. A residential cohort study in the geothermal area of Mt. Amiata in Tuscany

BACKGROUND

Geothermal power plants for the production of electricity are currently active in Mt. Amiata, Italy. The present study aimed to investigate the association between chronic low-level exposure to H₂S and health outcomes, using a residential cohort study design.

METHODS

Spatial variability of exposure to chronic levels of H₂S was evaluated using dispersion modelling. Cohorts included people residing in six municipalities of the geothermal district from 01/01/1998 to 31/12/2016. Residence addresses were georeferenced and each subject was matched with H₂S exposure metrics and socio-economic status available at census tract level. Mortality and hospital discharge data for neoplasms and diseases of the respiratory, central nervous and cardiovascular systems were taken from administrative health databases. Cox proportional hazard models were used to test the association between H₂S exposure and outcomes, with age as the temporal axis and adjusting for gender, socio-economic status and calendar period.

RESULTS

The residential cohort was composed of 33,804 subjects for a total of 391,002 person-years. Analyses reported risk increases associated with high exposure to H₂S for respiratory diseases (HR = 1.12 95%CI: 1.00-1.25 for mortality data; HR = 1.02 95%CI: 0.98-1.06 for morbidity data), COPD and disorders of the peripheral nervous system. Neoplasms were negatively associated with increased H₂S exposure.

CONCLUSIONS

The most consistent findings were reported for respiratory diseases. Associations with increased H₂S exposure were coherent in both mortality and hospitalization analyses, for both genders, with evidence of exposure-related trends. No positive associations were found for cancer or cardiovascular diseases.

H2S induces Th1/Th2 imbalance with triggered NF-κB pathway to exacerbate LPS-induce chicken pneumonia response

H₂S is one of the air pollutants, which can cause multiple organ damage to the body. H₂S exposure will directly damage respiratory system and cause inflammatory reaction. In this experiment, the effect of H₂S on LPS-induce chicken pneumonia is explored from the Th1/Th2 balance and the NF-κB pathway. 42-day-old broilers was selected as research object, exposed to exogenous H₂S, received an intraperitoneal injection of LPS to establish inflammatory model on forty-second days. We carry out qRT-PCR and Western blot to detect the expression of cytokines secreted by Th1/Th2, PPAR-γ/HO-1 genes, NF-κB pathway genes and the downstream genes COX-2 and iNOS. We found the expression of IL-4, IL-6, TNF-α and IL-1β increased and that of IFN-γ decreased, which indicating the immune imbalance of Th1/Th2 was occurred and the level of PPAR-γ/HO-1 was significantly suppressed. In addition, the activation of I-κB-β and NF-κB genes with the degradation of I-κB-α indicated that NF-κB pathway has been activated, which accompanied with COX-2, PGE and iNOS increasing. These results suggested that H₂S exposure can lead to Th1/Th2 immune imbalance, repress the anti-inflammatory effect of PPAR-γ/HO-1, and then activate NF-κB pathway-related genes and the downstream genes to aggravate pneumonia induced by LPS.

Dietary and Endocrine Regulation of Endogenous Hydrogen Sulfide Production: Implications for Longevity

SIGNIFICANCE

Hydrogen sulfide (H₂S) at the right concentration is associated with numerous health benefits in experimental organisms, ranging from protection from ischemia/reperfusion injury to life span extension. Given the considerable translation potential, two major strategies have emerged: supplementation of exogenous H₂S and modulation of endogenous H₂S metabolism. Recent Advances: Recently, it was reported that hepatic H₂S production capacity is increased in two of the best-characterized mammalian models of life span extension, dietary restriction, and hypopituitary dwarfism, leading to new insights into dietary and hormonal regulation of endogenous H₂S production together with broader changes in sulfur amino acid (SAA) metabolism with implications for DNA methylation and redox status.

CRITICAL ISSUES

Here, we discuss the role of dietary SAAs and growth hormone (GH)/thyroid hormone (TH) signaling in regulation of endogenous H₂S production largely via repression of H₂S generating enzymes cystathionine γ-lyase (CGL) and cystathionine β-synthase (CBS) on the level of gene transcription, as well as reciprocal regulation of GH and TH signaling by H₂S itself. We also discuss plasticity of CGL and CBS gene expression in response to environmental stimuli and the potential of the microbiome to impact overall H₂S levels.

FUTURE DIRECTIONS

The relative contribution of increased H₂S to health span or lifespan benefits in models of extended longevity remains to be determined, as does the mechanism by which such benefits occur. Nonetheless, our ability to control H₂S levels using exogenous H₂S donors or by modifying the endogenous H₂S production/consumption equilibrium has the potential to improve health and increase "shelf-life" across evolutionary boundaries, including our own. Antioxid. Redox Signal. 28, 1483-1502.

Effects of ambient air pollution from municipal solid waste landfill on children's non-specific immunity and respiratory health

This cross-sectional study investigated the association between air pollutant (AP) and respiratory health of 951 children residing near a municipal solid waste (MSW) landfill in Northern China. Results showed that students in non-exposure areas had significantly higher levels of lysozyme, secretory immunoglobulin A (SIgA), and better lung capacity than students in exposure areas (p < .05). Multiple regression model analysis indicated that lysozyme levels exhibited a consistent negative association with methane (CH₄: β = -76.3, 95% CI -105 to -47.7) and sulfuretted hydrogen (H₂S: β = -11.7, 95% CI -20.2 to -3.19). In addition, SIgA levels were negatively associated with H₂S (β = -68.9, 95% CI -97.9 to -39.9) and ammonia (NH₃: β = -30.3, 95% CI -51.7 to -8.96). Among all AP, H₂S and sulfur dioxide (SO₂) were the most robustly related with reduced lung function. H₂S exposure was negatively associated with six lung function indices, 1-s forced expiratory volume (FEV1%), mean forced expiratory flow between 25% and 75% (MMF), maximum voluntary ventilation (MVV), and forced expiratory flow at 25%, 50%, and 75% of the pulmonary volume (FEF25, FEF50, FEF75); and SO₂ was negatively associated with FEV1%, MVV, FEF25, FEF50 and FEF75. Our results suggested that AP exposure was negatively associated with more lung function parameters in boys than in girls. In conclusion, our findings suggested that children living adjacent to landfill sites were more likely to have deficient non-specific immunity and impaired lung function.

Cd2+-Doped Amorphous TiO2 Hollow Spheres for Robust and Ultrasensitive Photoelectrochemical Sensing of Hydrogen Sulfide

Hydrogen sulfide is a highly toxic molecule to human health, but high-performance detection of it remains a challenge. Herein, we report an ultrasensitive photoelectrochemical (PEC) sensor for H₂S by modifying indium tin oxide (ITO) electrodes with Cd²⁺-doped amorphous TiO₂ hollow spheres, which are prepared by templating against colloidal silica particles followed by a cadmium-sodium cation exchange reaction. The amorphous TiO₂ hollow spheres act as both the probing cation carrier and the photoelectric beacon. Upon exposure to sulfide ions, the photocurrent of the functionalized photoanode proportionately decreases in response to the formation of CdS nanoparticles. The decreased photocurrent could be attributed to the mismatching bandgap between the amorphous TiO₂ and CdS nanoparticles: the photoexcited electrons and holes from amorphous TiO₂ are transferred to the conduction band and valence band of CdS, respectively, and then recombined. The decrease in photocurrent is linear with the concentration of sulfide ions in the range from 1 to 10 000 pmol L^-1 with a detection limit of 0.36 pmol L^-1. Enabled by a unique sensitization mechanism, this PEC sensor features excellent performance in a wide linear range, high selectivity and sensitivity, high stability, and low fabrication cost.

Decrease in male mouse fertility by hydrogen sulfide and/or ammonia can Be inheritable

Numerous epidemiological studies suggest that air pollutants cause a decline in the quality of human spermatozoa and thus a reduction in fertility. However, the exact cause of infertility remains unknown. Air pollution gases, such as NH₃ and H₂S are either free or bound to airborne particular materials (PM) and are abundant and reactive. The aim of this current investigation was to explore the impacts of NH₃ and/or H₂S on male fertility and the underlying mechanisms. Male mouse exposed to H₂S and/or NH₃ and after two generations were used to evaluate the impacts on fertility. The fertility, and spermatozoa quality parameters and proteins involved in spermatogenesis were investigated. Our current investigation demonstrates: i) H₂S and/or NH₃ decrease male fertility by 20-30%, reduce the spermatozoa concentration about 20-40%, decrease 10-20%, increase around 30%; ii) the reduction in male fertility by H₂S and/or NH₃ can be inheritable; iii) H₂S and/or NH₃ can diminish male fertility through the disruption of spermatogenesis without affecting other body parameters such as body weight and organ index. One component of air pollutants, for example NH₃, does not have a severe impact; however, two or more pollutants such as H₂S and NH₃ combined can cause serious health problems, especially with regard to male fertility. We suggest that greater attention should be paid to these air pollutants to improve human health and fertility.

Sulphurous Mineral Waters: New Applications for Health

Sulphurous mineral waters have been traditionally used in medical hydrology as treatment for skin, respiratory, and musculoskeletal disorders. However, driven by recent intense research efforts, topical treatments are starting to show benefits for pulmonary hypertension, arterial hypertension, atherosclerosis, ischemia-reperfusion injury, heart failure, peptic ulcer, and acute and chronic inflammatory diseases. The beneficial effects of sulphurous mineral waters, sulphurous mud, or peloids made from sulphurous mineral water have been attributed to the presence of sulphur mainly in the form of hydrogen sulphide. This form is largely available in conditions of low pH when oxygen concentrations are also low. In the organism, small amounts of hydrogen sulphide are produced by some cells where they have numerous biological signalling functions. While high levels of hydrogen sulphide are extremely toxic, enzymes in the body are capable of detoxifying it by oxidation to harmless sulphate. Hence, low levels of hydrogen sulphide may be tolerated indefinitely. In this paper, we review the chemistry and actions of hydrogen sulphide in sulphurous mineral waters and its natural role in body physiology. This is followed by an update of available data on the impacts of exogenous hydrogen sulphide on the skin and internal cells and organs including new therapeutic possibilities of sulphurous mineral waters and their peloids.

Ambient geothermal hydrogen sulfide exposure and peripheral neuropathy

The mechanism of toxicity of hydrogen sulfide (H₂S) gas is thought mainly to operate through effects on the nervous system. The gas has high acute toxicity, but whether chronic exposure causes effects, including peripheral neuropathy, is yet unclear. The city of Rotorua, New Zealand, sits on an active geothermal field and the population has some of the highest measured ambient H₂S exposures. A previous study in Rotorua provided evidence that H₂S is associated with peripheral neuropathy. Using clinical methods, the present study sought to investigate and possibly confirm this association in the Rotorua population. The study population comprised 1635 adult residents of Rotorua, aged 18-65. Collected data relevant to the peripheral neuropathy investigation included symptoms, ankle stretch reflex, vibration sensitivity, as measured by the timed-tuning fork test and a Bio-Thesiometer (Bio-Medical Instrument Co., Ohio), and light touch sensitivity measured by monofilaments. An exposure metric, estimating time-weighted H₂S exposure across the last 30 years was used. Principal components analysis was used to combine data across the various indicators of possible peripheral neuropathy. The main data analysis used linear regression to examine associations between the peripheral nerve function indicators and H₂S exposure. None of the peripheral nerve function indicators were associated with H₂S exposure, providing no evidence that H₂S exposure at levels found in Rotorua is a cause of peripheral neuropathy. The earlier association between H₂S exposure and peripheral neuropathy diagnoses may be attributable to the ecological study design used. The possibility that H₂S exposure misclassification could account for the lack of association found cannot be entirely excluded.