Nitrate and nitrite contamination in drinking water and cancer risk: A systematic review with meta-analysis

Tapwater exposures, residential risk, and mitigation in a PFAS-impacted-groundwater community

Tapwater (TW) safety and sustainability are priorities in the United States. Per/polyfluoroalkyl substance(s) (PFAS) contamination is a growing public-health concern due to prolific use, widespread TW exposures, and mounting human-health concerns. Historically-rural, actively-urbanizing communities that rely on surficial-aquifer private wells incur elevated risks of unrecognized TW exposures, including PFAS, due to limited private-well monitoring and contaminant-source proliferation in urbanizing landscapes. Here, a broad-analytical-scope TW-assessment was conducted in a hydrologically-vulnerable, Mississippi River alluvial-island community, where PFAS contamination of the shallow-alluvial drinking-water aquifer has been documented, but more comprehensive contaminant characterization to inform decision-making is currently lacking. In 2021, we analyzed 510 organics, 34 inorganics, and 3 microbial groups in 11 residential and community locations to assess (1) TW risks beyond recognized PFAS issues, (2) day-to-day and year-to-year risk variability, and (3) suitability of the underlying sandstone aquifer as an alternative source to mitigate TW-PFAS exposures. Seventy-six organics and 25 inorganics were detected. Potential human-health risks of detected TW exposures were explored based on cumulative benchmark-based toxicity quotients (∑TQ). Elevated risks (∑TQ ≥ 1) from organic and inorganic contaminants were observed in all alluvial-aquifer-sourced synoptic samples but not in sandstone-aquifer-sourced samples. Repeated sampling at 3 sites over 52-55 h indicated limited variability in risk over the short-term. Comparable PFAS-specific ∑TQ for spatial-synoptic, short-term (3 days) temporal, and long-term (3 years quarterly) temporal samples indicated that synoptic results provided useful insight into the risks of TW-PFAS exposures at French Island over the long-term. No PFAS detections in sandstone-aquifer-sourced samples over a 3 year period indicated no PFAS-associated risk and supported the sandstone aquifer as an alternative drinking-water source to mitigate community TW-PFAS exposures. This study illustrated the importance of expanded contaminant monitoring of private-well TW, beyond known concerns (in this case, PFAS), to reduce the risks of a range of unrecognized contaminant exposures.

Electronic structure of aqueous nitrite and nitrate ions from resonant inelastic X-ray scattering

In a comparative synchrotron X-ray absorption, non-resonant X-ray emission and resonant inelastic X-ray scattering investigation of aqueous nitrite and nitrate ions, we access both their unoccupied and occupied valence electronic structures. Complementary information is gained through the sensitivity to specific orbitals at the nitrogen and the oxygen 1s absorption edges. In particular, scattering through the pronounced 1s → π* resonances in combination with the scattering anisotropy and symmetry selection rules allow for an unambiguous assignment of molecular orbitals to their detected spectroscopic fingerprints. The nuclear dynamics in the 1s core-excited states are discussed in the context of the vibrational substructure of the detected spectral lines and signatures of core-excited state symmetry breaking are characterized through an analysis of the excitation energy detuning dependent spectra in combination with the involved potentials. A comparison between TD-DFT based spectrum simulations for isolated molecules and sampled structures from a QM/MM simulation reveals signatures of symmetry breaking induced by the solute-solvent interactions and a different response of spectral signatures of in- and out-of-plane orbitals to the solution environment.

Nanozyme-based biosensors for food contaminants detection: advances, challenges, and prospects

The presence of food contaminants poses a growing threat to public health. Developing advanced and reliable biosensing methods with high sensitivity, specificity, and reproducibility for detecting food contaminants is an urgent requirement for food safety control. Nanozymes, recognized for their enzyme-mimicking catalytic activities and the unique physicochemical properties of nanomaterials, have been extensively utilized in the development of diverse biosensors for food safety assays. Recent years have witnessed an exponential surge in relevant publications, garnering considerable research interest. This review summarizes recent advancements in the catalytic mechanisms of peroxidase- and oxidase-like nanozymes and provides a comprehensive discussion on the construction, sensing mechanisms, and practical applications of nanozymes-based biosensors developed for detecting food contaminants over the past five years. These biosensors include colorimetric, fluorescence, chemiluminescent, electrochemical, surface-enhanced Raman scattering, multi-modal, and other types, used for detecting food contaminants such as mycotoxins, pathogens, pesticides, veterinary drugs, illegal additives, and heavy metals. The review also addresses current challenges and prospects in this field, aiming to summarize advancements and promote further exploration of nanozyme-based sensing platforms to guarantee food safety.

Nitrate pollution index and age wise health risk appraisal for the Pambar River basin in south India

Water and human healthcare are common concerns for everyone, resonating with the sustainable development goal. In Pambar River basin, south India, groundwater samples were obtained in 100 locations from open and bore wells to assess the quality of groundwater based on hydrochemical constituents like pH (Hydrogen Ion Concentration), CO₃2- (carbonate), Ca2⁺ (calcium), HCO₃- (bicarbonate), Cl- (chloride), Mg2⁺ (magnesium), SO₄2- (sulfate), K⁺ (potassium), Na⁺ (sodium), TDS (Total Dissolved Solids) with a special focus on NO₃- (nitrate) enrichment in groundwater and health risk computed from consumption of nitrate enriched water by different age categories of people, and acceptableness of water for consumption depends on the range of NPI (Nitrate Pollution Index). The nitrate content in subsurface water samples falls from 0.7 to 187.5 mg/L. Out of 100 samples, 31 samples surpassed the WHO, 2017 recommended limit for drinking purpose (> 45 mg/L). The calculated nitrate pollution index (NPI) values of samples  represent clean class (n = 43), light pollution class (n = 26), moderate pollution class (n = 9), significant class (n = 11) and very significant class (n = 11). The correlation matrix explains nitrate is weakly correlated with pH, magnesium, calcium, and potassium, and negatively associated with TDS, sodium, bicarbonate, chloride, and sulfate. The human health risk assessment computed from oral intake and dermal contact indicated that 36%, 34%, 31%, 36%, and 31% of samples for children, younger women, elder women, younger men, and elder men respectively, had a total hazard index (THI) > 1, indicating potential health risks. The nitrate enrichment in the subsurface water is caused by human-induced factors like fertilizers usage for agriculture, and leaching of animal waste. The health risk and water quality study suggest regular monitoring and managing the quality of groundwater for making the healthy society.

Long-Term Exposure to Nitrate and Trihalomethanes in Drinking Water and Gastric Cancer: A Multicase-Control Study in Spain (MCC-Spain)

BACKGROUND

Disinfection byproducts and N-nitroso compounds (NOC) formed endogenously after nitrate ingestion have been shown to be carcinogenic in animal studies, but epidemiological evidence is limited, especially in relation to gastric cancer.

OBJECTIVE

We evaluated the association between drinking water exposure to nitrate and trihalomethanes (THMs) and gastric cancer in a multicase-control study conducted in Spain (MCC-Spain).

METHODS

In 2008-2013, 254 hospital-based incident gastric cancer cases and 2,365 population-based controls were recruited, providing information on residential histories and type of water consumed. Adult lifetime average nitrate and THM levels in residences from age 18 until 2 years before the interview were estimated and linked with water consumption information to calculate waterborne ingested nitrate, brominated (Br)-THMs, and chloroform. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression, with adjustment for potential confounders. We assessed the effect modification by factors influencing endogenous NOC formation.

RESULTS

Median [percentile 25th (P25)-percentile 75 (P75)] (P 25 - P 75 ) lifetime waterborne ingested nitrate (mg / day ), Br-THMs (μ g / day ), and chloroform (μ g / day ) were 2.7 (1.4-5.6), 3.8 (1.5-8.1), and 12.2 (4.0-23.7), respectively, in cases and 3.8 (1.8-8.5), 5.7 (2.6-19.2), and 12.9 (4.6-24.5) in controls, respectively. Adjusted OR (95% CI) for gastric cancer comparing nitrate intake > 9.7 vs. ≤ 9.7 mg / day (percentile 80th, P80) was 1.42 (0.88, 2.29). This association was more pronounced among participants with low consumption of vegetables [2.24 (1.02, 4.91)], vitamin C [2.10 (0.94, 4.71)], and vitamin E [2.81 (1.16, 6.78)] and among those with high consumption of alcohol [2.78 (0.98, 7.93)] or processed meat [1.91 (0.97, 3.75)]. When stratified by age, the association only remained in the > 65 years of age group (median 73 years of age). OR for gastric cancer comparing Br-THM ingestion ≥ vs. 80 th < 80 th percentile was 0.65 (0.33, 1.28) and for chloroform was 1.36 (0.87, 2.14). Comparable ORs were found for residential concentrations.

CONCLUSIONS

Long-term waterborne nitrate exposure below regulatory limits may increase gastric cancer risk among older adults and in those with poor dietary patterns. These findings need to be confirmed by cohort studies with larger sample sizes. https://doi.org/10.1289/EHP15039.

Nitrate pollution in urban runoff: A comprehensive risk assessment for human and ecological health

Nitrate pollution in urban runoff poses significant environmental and public health risks, with its impact varying across different land use types. This study investigates nitrate concentrations in runoff from residential, commercial, industrial, and traffic zones in Tehran, Iran, using Event Mean Concentration (EMC) analysis and Monte Carlo simulations to assess both ecological and human health risks. The results indicate that industrial and traffic zones exhibit the highest nitrate concentrations, reaching 58.13 mg/L, significantly exceeding regulatory thresholds. Ecological risk assessments highlight the potential for aquatic system degradation, while health risk evaluations reveal hazard index (HI) values surpassing the safe limit (HI > 4), particularly in industrial and high-traffic areas. These findings underscore the need for targeted mitigation strategies, including the implementation of green infrastructure and stricter pollution control measures, to improve urban water quality and reduce associated risks.

High-Reproducibility and -Stability All-Solid-Contact Nitrate Ion-Selective Electrode with CoWSe2 as Solid Contact for Nitrate Monitoring in Wetland Soil

The monitoring of nitrate ions is of great significance for human health, agricultural development, and environmental protection. All-solid-state nitrate ion-selective electrodes (ASS-NO3--ISEs), as an important NO3- analysis method, still have two challenges of poor stability and reproducibility due to the ill-defined phase boundary between the solid-contact (SC) layer and the ion-selective membrane (ISM). In this work, a novel strategy for constructing the ASS-NO3--ISEs based on CoWO4, CoWS4, CoWSe2, or CoSe2 as SC layers was reported for improving the stability and reproducibility. The result shows that the developed CoWSe2-based NO3--ISE exhibits a good Nernstian response slope of -61.9 ± 0.4 mV dec-1 in the activity range from 1.0 × 10-6 to 7.5 × 10-2 M and a detection limit of 1.0 × 10-6 M. A good long-term stability (as low as 2.3 ± 0.4 μV h-1) of the CoWSe2-based NO3--ISE is the primary reason for the high redox capacitance of the ternary selenide. Experimental results show a surprisingly good reproducibility of approximately 0.5 mV for five individual ASS-NO3--ISEs. Notably, electrochemical experiments and scanning electron microscopy mapping tests are used to predict the ion-electron transduction mechanism in which the lipophilic anion (tetrakis(4-chlorophenyl)borate) participates in the transduction process at the SC/ISM interface to stabilize the electrode potential and provide high reproducibility. It was further proved that the introduction of CoWSe2 as the SC layer maintains an excellent anti-interference to water layers, light, and gas. Hence, the CoWSe2-based ASS-NO3--ISEs achieve accurate detection for free NO3- in wetland soil and the estuary of the Yellow River delta.

Hydrogenation-Facilitated Spontaneous N-O Cleavage Mechanism for Effectively Boosting Nitrate Reduction Reaction on Fe2B2 MBene

The electrochemical reduction of toxic nitrate wastewater to green fuel ammonia under mild conditions has become a goal that researchers have relentlessly pursued. Existing designed electrocatalysts can effectively promote the nitrate reduction reaction (NO3RR), but the study of the catalytic mechanism is not extensive enough, resulting in no breakthroughs in performance. In this study, a novel mechanism of hydrogenation-facilitated spontaneous N-O cleavage was explored based on density functional theory calculations. Furthermore, the Ead-*OH (adsorption energy of the adsorbed *OH) was used as a key descriptor for predicting the occurrence of spontaneous N-O bond cleavage. We found that Ead-*OH < -0.20 eV results into spontaneous N-O bond cleavage. However, excessively strong adsorption of OH* hinders the formation of water. To address this challenge, we designed the eligible Fe2B2 MBene, which shows excellent catalytic activity with an ultra-low limiting potential for NO3RR of -0.22  V under this novel reaction mechanism. Additionally, electron-deficient Fe active sites could inhibit competing hydrogen evolution reactions (HERs), which provides high selectivity. This work may offer valuable insights for the rational design of advanced electrocatalysts with enhanced performance.

Nitrate contamination in groundwater across Switzerland: Spatial prediction and data-driven assessment of anthropogenic and environmental drivers

Excessive nitrate in groundwater, which is primarily caused by anthropogenic activities, is a worldwide problem. Consequently, Goal 6 of the UN Sustainable Development Goals lists nitrate as one of the key indicators of groundwater quality. However, in most countries, the nationwide occurrence of nitrate is unknown, as the monitoring networks only represent small points in space. To bridge this gap, machine learning modelling that predicts nitrate concentrations at a high spatial resolution is a promising tool to identify high-risk areas. Here, we use random forest machine learning to predict nitrate concentrations across Switzerland based on 1336 monitoring sites. The model revealed that approximately 35 % of the Swiss Plateau, Switzerland's most populous region, has a high probability of exceeding the Swiss guideline value of 25 mg/l for groundwater nitrate. We also investigated the individual importance and influence of anthropogenic and environmental variables associated with high nitrate concentrations by combining SHapley Additive exPlanations with expert knowledge of physical and geochemical processes. In addition to well-known influences of anthropogenic features (e.g. land use), we found that other environmental features including high springtime precipitation, low summertime precipitation, low soil organic carbon content, low river density and greater distance to large rivers, were indicative of high nitrate concentrations. These features directly relate to large-scale nitrate transport and attenuation processes (denitrification and dilution), but have received sparse attention in nitrate risk assessment and mitigation measures. Therefore, the approach and results of our study can be useful for nitrate studies around the world.

Environmental Pollution and Reproductive Health: The Cause for Concern

Currently, there is a growing concern for human health with the rise of environmental pollution. Water contamination and health problems had been understood. Sanitation-related health issues have been overcome in the greater part of the world. Progressive industrialization has caused a number of new pollutants in water and in the atmosphere. It is a growing concern for the human health, especially upon the reproductive health. Current researchers provide a strong association between the rising concentrations of ambient pollutants and the adverse health impact. Furthermore, the pollutants have the adverse effects upon reproductive health as well. Major concern is for the health of a pregnant woman and her baby. Maternal-fetal inflammatory response due to the pollutants affects the pregnancy outcome adversely. Preterm labor, fetal growth restriction, intrauterine fetal death, and stillbirths have been observed. Varieties of pathological processes including inflammation, endocrine dysfunction, epigenetic changes, oxidative and nitrosative stress, and placental dysfunction have been explained as the biological plausibility. Prospective studies (systematic review and meta-analysis) have established that exposure to particulate matters (PM) and the nanoparticles (NP) leads to excessive oxidative changes to cause DNA mutations, lipid peroxidation and protein oxidation. Progressive industrialization and emergence of heavy metals, micro- (MP) and nanoparticles (NP) in the atmosphere and in water are the cause for concern. However, most of the information is based on studies from industrialized countries. India needs its own country-based study to have the exact idea and to develop the mechanistic pathways for the control.

Chemical, physical and microbiological analyses of different drinking water sources among diverse governorates in Lebanon

Multiple sources of drinking water are commonly used in Lebanon, including bottled water, tap water, potable water, spring, artesian wells and station filtered water. The quality of these waters is of great concern, as its contamination could lead to waterborne outbreaks. We aimed to investigate the quality of drinking water in Lebanon, considering different sources and geographic distributions, and to compare their profiles across diverse governorates. A total of 200 samples (133 potable water, 28 station filtered water, 18 tap water, 8 spring water, 7 artesian well water and 6 bottled water) from five Lebanese governorates (Nabatieh, Beqaa, Mount Lebanon, Baalbek-Hermel and South Lebanon) were analyzed for physico-chemical and bacterial properties. The results indicated elevated phosphate concentrations in all areas (> 1.35 mg/L). Additionally, all analyzed bacteria were present in all regions, highlighting the lack of contamination-free sources. While in Baalbek-Hermel, followed by Nabatieh, exhibited the highest chemical levels, microbiological contamination particularly total and fecal coliforms, was consistent across governorates, showing no significant difference (p > 0.05). However, the distribution of Streptococcus and Pseudomonas Aeruginosa varied significantly among the different zones (p < 0.001 and p < 0.01, respectively). All drinking water sources in various Lebanese governorates were found to be contaminated with multiple contaminants. Based on these findings, the sources used for drinking in Lebanon are not entirely safe and require monitoring.

Integrated machine learning based groundwater quality prediction through groundwater quality index for drinking purposes in a semi-arid river basin of south India

The main objective of this study is to predict and monitor groundwater quality through the use of modern Machine Learning (ML) techniques. By employing ML techniques, the research effectively evaluates groundwater quality to forecast its future trends. Five machine learning models Logistic Regression (LR), Support Vector Machine (SVM), Random Forest (RF), Adaptive Boosting (AdaBoost), Extreme Gradient and Boosting (XGBoost) were used here to predict the water quality by assessing the physical and chemical parameters such as electrical conductivity (EC), hydrogen ion (pH) concentration, total dissolved solids (TDS), chemical parameters such as, sodium (Na+), magnesium (Mg2+), calcium (Ca2+), potassium (K+), bicarbonates (HCO3-), fluoride (F-), sulphate (SO42-), chloride (Cl-), and nitrate (NO3-) in 94 dug and bore wells from the semi-arid river basin (Arjunanadi) in Tamil Nadu, India. The pH of the samples is alkaline nature. Gibb's diagram suggested the rock-water dominance and minor influence of evaporation and crystallization on the hydrochemistry. From water quality index, 599.75 km2 (53%) of area has a good quality and 536.75 km2 (47%) of area has poor water quality. Water Quality Index values (WQI) of water quality formed baseline data for the prediction models as a dependent variable, and the physicochemical parameters were used as independent variables. The model efficacies were assessed using statistical error such as Relative Squared Residual (RSR) error, Nash-Sutcliffe efficiency (NSE), Mean Absolute Percentage Error (MAPE), Coefficient of determination (R2) and final accuracy. In this study, the LR model provided the minimal error (RSR = 0.22, NSE = 0.95, MAPE = 1.3) with an accuracy of 95% in predicting the water quality. The performance of the ML models is in the sequence of SVM > Adaboost > XGBoost > RF. This study helps the lawmakers and administrators for creating awareness on modern techniques for predicting and monitoring groundwater quality on the general public and supporting to achieve the sustainable development goals 3 and 6 for clean and healthy community.

Insight into the bimetallic structure sensibility of catalytic nitrate reduction over Pd-Cu nanocrystals

Catalytic reduction of nitrate over bimetallic catalysts has emerged as a technology for sustainable treatment of nitrate-containing groundwater. However, the structure of bimetallic has been much less investigated for catalyst optimization. Herein, two main types of Pd-Cu bimetallic nanocrystal structures, heterostructure and intermetallic, were prepared and characterized using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show that two individual Pd and Cu nanocrystals with a mixed interface exist in the heterostructure nanocrystals, while Pd and Cu atoms are uniformly distributed across the intermetallic Pd-Cu nanocrystals. The catalytic nitrate reduction experiments were carried out in a semibatch reactor under constant hydrogen flow. The nitrate conversion rate of the heterostructure Pd-Cu nanocrystals supported on α-Al2O3, γ-Al2O3, SBA-15, and XC-72R exhibited 3.82-, 6.76-, 4.28-, 2.44-fold enhancements relative to the intermetallic nanocrystals, and the nitrogen and nitrite were the main products for the heterostructure and intermetallic Pd-Cu nanocrystals, respectively. This indicates that the catalytic nitrate reduction over Pd-Cu catalyst is sensitive to the bimetallic structures of the catalysts, and heterostructure bimetallic nanocrystals exhibit better catalytic performances on both the activity and selectivity, which may provide new insights into the design and optimization of catalysts to improve catalytic activity and selectivity for nitrate reduction in water.

Rapid and Facile Organic Ion-Associate Liquid-Phase Extraction and Spectrophotometric Quantification of Nitrite in Environmental Water Samples

Nitrite is a health and environmental hazard and pollutes water sources globally, but sensitive, rapid, and facile quantification methods are lacking. Herein, we report a method for extracting and quantifying low-concentration nitrite in surface water using minimal sample and solvent volumes. The nitrite reacted with sulfanilamide and N-1-naphthylethylenediammonium dichloride (NED), yielding an azo dye for extraction into an organic ion-associate liquid phase (IALP) formed in situ using ethylhexyloxypropylammonium and dodecyl sulfate ions. The addition of sodium acetate increased the pH, decreasing the cation charge from +2 to +1, improving extraction efficiency. Further, adding NaCl doubled the IALP volume, reduced the required standing time, and minimally affected absorbance, and adding concentrated HCl to the IALP enhanced the absorbance intensity via dye protonation. Crucially, the method achieved a 30-fold concentration factor compared to traditional pre-treatment methods, even without centrifugation, as well as a limit of detection of 0.09 µg NO2-N/L. Spiked recovery tests with river and seawater samples (93-103%) matched those of established methods. Digital imaging of IALP-extracted lake water yielded a limit of detection of 0.4 µg NO2-N/L. The method is a sensitive, efficient approach for nitrite detection, enabling rapid environmental monitoring via spectrophotometry and digital imaging.

Quantifying the environmental fate and source of nitrate contamination using dual-isotope tracing coupled with nitrogen cascade model on the basin scale

Nitrate (NO3-) contamination in riverine networks has threatened the environment and human health. Clarifying the NO3- source and environmental fate within the basin under different underlying surfaces is essential for water body protection, especially China's two mother rivers. A series of combination methods were established i.e., field survey, index measurements, isotope-tracing techniques, and material flow analysis in four typical basins to investigate the spatiotemporal variation and source of NO3- pollution and nitrogen cascade characteristics. The dual-isotope coupled with MixSIAR model revealed that manure and sewage were the major NO3- source in the irrigation basin (WY, 76.7 %), hilly mountainous basin (YC, 52.3 %), and plateau lake basin (DC, 48.7 %). However, for the plain-river network basin (CZ), soil leachate was the main source (55.5 %). In terms of the N losses to water within agri-environment system, livestock-breeding system in three basins made the biggest contribution among the systems, WY (77.3 %), YC (47.3 %), and DC (41.8 %). While in CZ, about 34.4 % of N was delivered from the crop-production system. The N cascade model verified the results of isotope-tracing techniques for each basin. The study provides new insight into NO3--tracing combining hydrogeochemical indicators, isotopic-tracing techniques, and material flow analysis and guides strategies for mitigating the negative impacts of NO3- pollution on aquatic environments on basin scale.

Safeguarding Groundwater Nitrate within Regional Boundaries in China

Groundwater, essential for irrigation, industry, and drinking, plays a crucial role in environmental health and human well-being. A major threat to groundwater quality is nitrate pollution, primarily stemming from human activities. Safeguarding nitrogen levels in groundwater within regional thresholds remains a global challenge. By integrating 3,134 groundwater samples and nitrogen budget modeling, we found that China's national average nitrate concentration has risen by 29% since the 2000s, reaching 14 mg N L-1. The main sources of nitrate contamination are cropland, landfills, and wastewater disposal, with average annual nitrogen leaching of 1.91 ± 0.16, 0.86 ± 0.18, and 0.63 ± 0.17 million tonnes, respectively; these sources collectively account for 73% of the total nitrate leakage during 2000-2020. Current robust mitigation practices could reduce nitrogen leaching into groundwater by 45% (1.93 million tonnes N), delivering a net societal benefit of US$83 billion in China. Nevertheless, this reduction remains insufficient to meet the safe nitrogen boundary for all provinces, underscoring a compelling necessity for additional measures and policy guidance tailored to protect groundwater resources on a site-specific basis.

Environmental factors inducing gastric cancer: insights into risk and prevention strategies

Gastric cancer, a prevalent malignant tumor worldwide, poses a significant challenge to global health. Despite ongoing advancements in treatment methods, its high incidence and mortality rates remain concerning. Although progress in treating gastric cancer is encouraging, a more critical focus is on enhancing prevention efforts. Understanding the risk factors associated with gastric cancer is crucial for its prevention. This article summarizes the environmental factors related to the development of gastric cancer and their prevention, including: Living or working environment factors (air pollution, water quality, soil pollution, radiation, altitude, climate), dietary habits (meat, high-fat diet, high-salt diet), lifestyle habits (smoking, Drinking, sleep, coffee), and viral and bacterial exposures (Epstein-Barr virus, Human cytomegalovirus, Helicobacter pylori). Additionally, the article discusses current research directions and aims to provide a reference for researchers, paving the way for future preventive and therapeutic strategies.

An integrated computational and graphical approach for evaluating the geochemistry and health risks of nitrate-contaminated water for six age groups

Nitrate contamination in drinking water poses significant health risks, particularly in rapidly urbanizing areas of developing countries. This study presents an integrated computational and graphical approach to evaluate the geochemistry and health risks of nitrate-contaminated water for six age groups in Southeast, Nigeria. The research employed a detailed methodology combining water nutrient pollution index (WNPI), nitrate pollution index (NPI), water pollution index (WPI), geochemical plotting techniques, stoichiometry, and health risk computations. Water samples from several locations were analyzed for physicochemical parameters and nitrate concentrations. Results revealed predominantly acidic conditions and varying levels of nitrate contamination. Geochemical analysis indicated that silicate weathering and ion exchange processes were the primary influences on water chemistry. The WPI identified 14.29% of samples as "extremely polluted" (WPI > 1), while the WNPI classified 7.14% of samples as "moderately polluted" (WNPI > 1). However, the NPI categorized the samples as safe, indicating low nitrate inputs from anthropogenic sources. Health risk assessments indicated low-moderate risks, with the highest total hazard index of 0.839 for the 6-12 months age group; thus, higher vulnerability for infants. Oral exposure was found to be the dominant pathway, contributing over 99.90% to the total risk. This research provides crucial insights for achieving the Sustainable Development Goals (SDGs) related to water quality and public health protection. The integrated approach offers a robust framework for water resource management and interventions in risk-prone areas. Future research should focus on expanding the spatial coverage, incorporating sensitivity analyses, and exploring advanced technologies for real-time monitoring and predictive modeling of water quality.

Gold nanoclusters decorated hollow ZIF-8 encapsulating iron-catecholates as oxidase mimetics for ratiometric colorimetric detection of nitrite

Gold nanoclusters decorated hollow ZIF-8 encapsulating iron-catecholates (Fe-HHTP@HZIF-8@ AuNCs) was formed through self-assembly of Fe3+ and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP), in situ embedding of ZIF-8, and Au3+-Zn2+ exchange reaction. Its morphology and structure were fully characterized by high-resolution transmission electron microscopy, X-ray diffraction, transmission electron microscopy element mapping, and X-ray photoelectron spectroscopy. Additionally, its oxidase-like activity was explored with Km of 0.21 mM and Vmax of 1.74 × 10-6 M·s-1 toward 3,3',5,5'-tetramethylbenzidine (TMB). Due to its excellent catalytic activity and nitrite mediated diazotization of oxTMB, a ratiometric colorimetric method for nitrite detection was established and validated with wide linear range (2.0-400.0 μM), low LOD (0.12 μM), high accuracy (recovery of 95.11-102.14%), and good selectivity. This method was then utilized to determine the nitrite content in sausages and tap water. This study provided a new idea for developing efficient nanozymes and offered an accurate approach for nitrite determination.

Fast preparing bioelectrode with conductive bioink for nitrite detection in high sensitivity and stability

Electrochemically active biofilms (EABs) for nitrite detection have high specificity, rapid response, operational simplicity, and extended lifespan advantages. However, their scale production remains challenging due to time-consuming and uniform preparation. In this study, a novel approach was proposed to fast fabricate an EAB biosensor with a synthetic biofilm electrode for nitrite detection. The biofilm electrode was prepared by coating bioinks with varying conductive materials onto the surface of the graphite sheets, showing short incubation time and good reproducibility. Incorporating conductive materials into the bioinks remarkably enhanced the maximum voltage of the first cycle of bioelectrode incubation, with an increase of up to 633% for carbon nanofibers. The nitrite reduction current was amplified by a factor of 2.97, due to the enhancement of extracellular electron transfer (EET). The developed nitrite biosensor exhibited a detection range of 0.1-15 mg NO2--N L-1, with a high sensitivity of 610.8 μA mM-1 cm-2, and a stabilization operation time of at least 280 cycles. This study not only provided valuable insights into conductive materials for synthetic biofilms but also presented a practical approach for the rapid preparation, scale production, and optimization of highly sensitive and stable EAB sensors.

Rapid low-level nitrate determination by UV spectroscopy in the presence of competing ions

The presence of excessive nitrate in environmental and drinking water even at low levels can pose both environmental and health hazards. Because of this, various methods for its removal have been investigated. Essential to conducting such research is a method to reliably quantify nitrate in relevant matrices. However, current approaches have drawbacks related to cost, analysis time or health hazards. This study evaluates a UV spectroscopy-based method for nitrate determination, suitable for quantifying low nitrate concentrations in the presence of bicarbonate, sulfate, chloride and phosphate. The limits of detection and quantification were found to be 0.003 ppm N and 0.0077 ppm N respectively, lower than that observed in the ion chromatography method it was compared to. Additionally, a calibration curve created with 11 standards ranging from 0 to 2.5 ppm N demonstrated an exceptionally strong correlation, with an R2 value greater than 0.9999. This method is developed with a focus on accessibility and speed, minimising hazards and waste generation for reduced environmental footprint. The effects of contaminants introduced through the use of commercial laboratory consumables are also discussed.

Advanced nitrate removal in sulfur autotrophic denitrification biofilter under dissolved oxygen shock and low temperature enhanced by boron oxide and magnesium oxide: Hydrogen sulfide accumulation and regulation

Strengthening nitrate removal stability of sulfur autotrophic denitrification (SAD) under environmental stress is of great urgency. This study established a biofilter filled with S0-based filter material modified by boron oxide and magnesium oxide (FMSBMg). Hydrogen sulfide (H2S) accumulation reached 18.89 ± 4.51 mg/L and 7.28 ± 2.03 mg/L in summer and winter. Air and water backwash flow rates of 3 m3/h and 150 L/h could reduce H2S accumulation to below 0.16 mg/L under dissolved oxygen (DO) of 4.4 ± 0.1 mg/L 0.4 ± 0.1 mg/L B3+ and 15.9 ± 0.3 mg/L Mg2+ released from FMSBMg enhanced nitrate removal stability under DO shock and temperature drop. NO3--Neff reached 5.2 ± 2.2 mg/L at 12.1 ± 0.8 °C. Coexistence of NH4+-N and NO2--N provided substrates for in situ enrichment of Anammox bacteria. Thiobacillus, Lysobacter and Brocadia abundances accounted for 53.9%, 2.5% and 1.8% in biofilter, respectively. This study could provide theoretical basis for SAD biofilter application and H2S regulation.

Selenium and concomitant anions removal in a fixed bed bioreactor to satisfy drinking water regulations and subsequent stability check of selenium-laden biosludge

This is the first successful report on selenium bio-attenuation to satisfy drinking water regulations as per Indian Standards (10 μg/L) in the presence of concomitant nitrate and sulfate from water sources utilizing a fixed bed bioreactor. The bioreactor was immunized with blended microbial culture and worked in downflow mode under anoxic conditions at 30 ± 2 °C for around 190 days under varying influent selenate (100-500 μg/L as selenium), nitrate (50 mg/L), sulfate concentrations (as per selenium removal) and necessary dose of acetic acid (as COD, a carbon source) in synthetic groundwater, operated at an empty bed contact time (EBCT) of 45-120 min. After supplying an adequate dosage of sulfate and alteration of EBCT, selenium was found to comply with drinking water regulations and nitrate was completely removed. X-ray diffraction and transmission electron microscopy analyses depicted nanocrystalline selenium sulfides (SeS and SeS2) formation as the possible mechanisms of selenium removal. Extended toxicity characteristic leaching procedure (TCLP) extractions confirmed a maximum selenium leaching of 52 and 282 μg/L during anoxic and oxic extractions, respectively. Long-term column leaching (>3-month equilibration) under aerobic conditions at pH 7 confirmed the produced precipitate to be essentially stable (∼0.14% Se leaching). This work exhibits the synchronous bioremoval of selenium and its co-anions from contaminated water complying with drinking water standards, and leaving a stable and non-hazardous selenium-laden biosludge.

Long-term spatiotemporal changes in nitrate contamination of municipal groundwater resources after sewerage network construction in the Hungarian Great Plain

Over the last decades, as a consequence of wastewater discharges and other anthropogenic sources, severe nitrate (NO3-) pollution has developed in municipal environment causing global concern. Thus, eliminating the potential sources of pollution is one of the major challenges of the twenty-first century, whereby sanitation services are essential for ensuring public health and environmental protection. In the present study, long-term monitoring (2011-2022) of shallow groundwater NO3- contamination in municipal environment was carried following the construction of the sewerage network (2014) in the light of the pre-sewerage situation. Our primary aim was to assess the long-term effects of sewerage on nitrate NO3- levels in the shallow groundwater and evaluate the efficiency of these sanitation measures over time. Based on the results, significant pollution of the shallow groundwater in the municipality was identified. During the pre-sewer period, NO3- concentrations exceeded the 50 mg/L limit in the majority of monitoring wells significantly, upper quartile values ranged between 341 and 623 mg/L respectively. Using Nitrate Pollution Index (NPI) and interpolated NO3- pollution maps, marked spatial north-south differences were detected. In order to verify the presence of wastewater discharges in the monitoring wells, the isotopic ratio shifts (δ) for 18O and D(2H) were determined, confirming municipal wastewater effluent. Variations in NO3-/Cl- molar ratios suggest also contamination from anthropogenic sources, including septic tank effluent from households and the extensive use of manure. Data series of 7 years (2015-2022) after the investment indicate marked positive changes by the appearance of decreasing trends in NO3- values confirmed by Wilcoxon signed rank test and ANOVA. By comparing the pre- and post-sewerage conditions, the mean NO3- value decreased from 289.7 to 175.6 mg/L, with an increasing number of monitoring wells with concentrations below the limit. Our results emphasise the critical role of sanitation investments, while also indicating that the decontamination processes occur at a notably slow pace. Detailed, long-term monitoring is therefore essential to ensure accurate follow-up of the ongoing changes. The results can provide information for local citizens and authorities to improve groundwater management tools in the region.

Identifying the spatial pattern and driving factors of nitrate in groundwater using a novel framework of interpretable stacking ensemble learning

Groundwater nitrate contamination poses a potential threat to human health and environmental safety globally. This study proposes an interpretable stacking ensemble learning (SEL) framework for enhancing and interpreting groundwater nitrate spatial predictions by integrating the two-level heterogeneous SEL model and SHapley Additive exPlanations (SHAP). In the SEL model, five commonly used machine learning models were utilized as base models (gradient boosting decision tree, extreme gradient boosting, random forest, extremely randomized trees, and k-nearest neighbor), whose outputs were taken as input data for the meta-model. When applied to the agricultural intensive area, the Eden Valley in the UK, the SEL model outperformed the individual models in predictive performance and generalization ability. It reveals a mean groundwater nitrate level of 2.22 mg/L-N, with 2.46% of sandstone aquifers exceeding the drinking standard of 11.3 mg/L-N. Alarmingly, 8.74% of areas with high groundwater nitrate remain outside the designated nitrate vulnerable zones. Moreover, SHAP identified that transmissivity, baseflow index, hydraulic conductivity, the percentage of arable land, and the C:N ratio in the soil were the top five key driving factors of groundwater nitrate. With nitrate threatening groundwater globally, this study presents a high-accuracy, interpretable, and flexible modeling framework that enhances our understanding of the mechanisms behind groundwater nitrate contamination. It implies that the interpretable SEL framework has great promise for providing valuable evidence for environmental management, water resource protection, and sustainable development, particularly in the data-scarce area.

Structure properties and industrial applications of anion exchange resins for the removal of electroactive nitrate ions from contaminated water

The presence of nitrates in lakes, rivers, and groundwater is common. Anion exchange resins (AER) are polymeric structures that contain functional groups as well as a variety of particle sizes that are used for removing nitrate ions from solutions. This article provides a concise review of the types and properties of AER, synthesis methods, characterization, and environmental applications of AER. It discusses how different factors affect the adsorption process, isotherm and kinetic parameters, the adsorption mechanism, and the maximum adsorption capacities. Additionally, the present review addresses AER's regeneration and practical stability. It emphasizes the progress and proposes future strategies for addressing nitrate pollution using AER to overcome the challenges. This review aims to act as a reference for researchers working in the advancement of ion exchange resins and presents a clear and concise scientific analysis of the use of AER in nitrate adsorption. It is evident from the literature survey that AER is highly effective at removing nitrate ions from wastewater effluents.

Trends in pulse voltammetric techniques applied to foodstuffs analysis: The food additives detection

Food additives are chemical compounds intentionally added during foodstuff production to control technological functions, such as pH, viscosity, stability (color, flavor, taste, and odor), homogeneity, and loss of nutritional value. These compounds are fundamental in inhibition the degradation process and prolonging the shelf life of foodstuffs. However, their inadequate employment or overconsumption can adversely affect consumers' health with the development of allergies, hematological, autoimmune, and reproductive disorders, as well as the development of some types of cancer. Thus, the development and application of simple, fast, low-cost, sensitivity, and selectivity analytical methods for identifying and quantifying food additives from various chemical classes and in different foodstuffs are fundamental to quality control and ensuring food safety. This review presents trends in the detection of food additives in foodstuffs using differential pulse voltammetry and square wave voltammetry, the main pulse voltammetric techniques, indicating the advantages, drawbacks, and applicability in food analysis. Are discussed the importance of adequate choices of working electrode materials in the improvements of analytical results, allowing reliable, accurate, and inexpensive voltammetric methods for detecting these compounds in foodstuffs samples.

Preparation of dicationic ionic liquid modified silica stationary phase for mixed-mode liquid chromatography and its application for food additive detection

BACKGROUND

Food safety has become an essential aspect of public concern and there are lots of detection means. Liquid chromatography plays a dominating role in food safety inspection because of its high separation efficiency and reproducibility. However, with the increasing complexity of real samples and monitoring requirements, conventional single-mode chromatography would require frequent column replacement and cannot separate different kinds of analytes on a single column simultaneously, which is costly and time-consuming. There is a great need for fabricating mixed-mode stationary phases and validating the feasibility of employing mixed-mode stationary phases for food safety inspection.

RESULTS

This work fabricated multifunctional stationary phases for liquid chromatography to determine diverse food additives under the mixed mode of RPLC/HILIC/IEC. Two dicationic ionic liquid silanes were synthesized and bonded onto the silica gel surface. The functionalized silica was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis. Both columns provide satisfactory separation performance towards 6 hydrophilic nucleosides, 4 hydrophobic polycyclic aromatic hydrocarbons, and 5 anions. Great repeatability of retention (RSD <0.1 %) and column efficiency (100330 plate/m) were obtained. Thermomechanical analysis and linear solvation energy relationship investigated the retention mechanism. Finally, the better in two prepared columns was employed to separate and determine the contents of NO2- and NO3- in vegetables(highest 4906 mg kg-1 NO3- in spinach), preservatives in bottled beverages (180.8 mg kg-1 sodium benzoate in soft drink), and melamine in milk with satisfactory performance and recovery rates ranging from 96.4 % to 105.6 %.

SIGNIFICANCE

This work developed a novel scheme for preparing mixed-mode stationary phases by dicationic ionic liquid which provides great separation selectivity. Most importantly, this work proved the superiority of employing mixed-mode stationary phases for food safety inspection, which might avoid high-cost and frequent changes of columns and chromatography systems in the near future.

Spatial consistency of co-exposure to air and surface water pollution and cancer in China

Humans can be exposed to multiple pollutants in the air and surface water. These environments are non-static, trans-boundary and correlated, creating a complex network, and significant challenges for research on environmental hazards, especially in real-world cancer research. This article reports on a large study (377 million people in 30 provinces of China) that evaluated the combined impact of air and surface water pollution on cancer. We formulate a spatial evaluation system and a common grading scale for co-pollution measurement, and validate assumptions that air and surface water environments are spatially connected and that cancers of different types tend to cluster in areas where these environments are poorer. We observe "dose-response" relationships in both the number of affected cancer types and the cancer incidence with an increase in degree of co-pollution. We estimate that 62,847 (7.4%) new cases of cancer registered in China in 2016 were attributable to air and surface water pollution, and the majority (69.7%) of these excess cases occurred in areas with the highest level of co-pollution. The findings clearly show that the environment cannot be considered as a set of separate entities. They also support the development of policies for cooperative environmental governance and disease prevention.

Nitrate: "the source makes the poison"

Interest in the role of dietary nitrate in human health and disease has grown exponentially in recent years. However, consensus is yet to be reached as to whether consuming nitrate from various food sources is beneficial or harmful to health. Global authorities continue to recommend an acceptable daily intake (ADI) of nitrate of 3.7 mg/kg-bw/day due to concerns over its carcinogenicity. This is despite evidence showing that nitrate consumption from vegetable sources, exceeding the ADI, is associated with decreased cancer prevalence and improvements in cardiovascular, oral, metabolic and neurocognitive health. This review examines the paradox between dietary nitrate and health and disease and highlights the key role of the dietary source and food matrix in moderating this interaction. We present mechanistic and epidemiological evidence to support the notion that consuming vegetable-derived nitrate promotes a beneficial increase in nitric oxide generation and limits toxic N-nitroso compound formation seen with high intakes of nitrate added during food processing or present in contaminated water. We demonstrate the need for a more pragmatic approach to nitrate-related nutritional research and guidelines. Ultimately, we provide an overview of our knowledge in this field to facilitate the various therapeutic applications of dietary nitrate, whilst maintaining population safety.

Non-thermal obliteration of critically ranked carbapenem-resistant Acinetobacter baumannii and its resistance gene in a batch atmospheric plasma reactor

Wastewater treatment plants (WWTPs) have been implicated as direct key reservoir of both antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) associated with human infection, as high concentrations of ARBs and ARGs have been detected in recycled hospital wastewater. Among the ARBs, the carbapenem-resistant Acinetobacter baumannii has been ranked as priority 1 (critical) pathogen by the World Health Organization (WHO), due to its overwhelming burden on public health. Therefore, this study is aimed at investigating non-thermal plasma (NTP) technology as an alternative disinfection step to inactivate this bacterium and its ARGs. Culture-based method and PCR were employed in confirming the carbapenem resistance gene blaNDM-1 in A. baumannii (BAA 1605). Suspension of carbapenem-resistant A. baumannii (24 h culture) was prepared from the confirmed isolate and subjected to plasma treatment at varying time intervals (3 min, 6 min, 9 min, 12 min, and 15 min) in triplicates. The plasma-treated samples were evaluated for re-growth and the presence of the resistance gene. The treatment resulted in a 1.13 log reduction after 3 min and the highest log reduction of ≥ 8 after 15 min, and the results also showed that NTP was able to inactivate the blaNDM-1 gene. The log reduction and gel image results suggest that plasma disinfection has a great potential to be an efficient tertiary treatment step for WWTPs.

Versatile applications of fullerenol nanoparticles

Nanomaterials have become increasingly important over time as research technology has enabled the progressively precise study of materials at the nanoscale. Developing an understanding of how nanomaterials are produced and tuned allows scientists to utilise their unique properties for a variety of applications, many of which are already incorporated into commercial products. Fullerenol nanoparticles C60(OH)n, 2 ≤ n ≤ 44 are fullerene derivatives and are produced synthetically. They have good biocompatibility, low toxicity and no immunological reactivity. In addition, their nanometre size, large surface area to volume ratio, ability to penetrate cell membranes, adaptable surface that can be easily modified with different functional groups, drug release, high physical stability in biological media, ability to remove free radicals, magnetic and optical properties make them desirable candidates for various applications. This review comprehensively summarises the various applications of fullerenol nanoparticles in different scientific fields such as nanobiomedicine, including antibacterial and antiviral agents, and provides an overview of their use in agriculture and biosensor technology. Recommendations are also made for future research that would further elucidate the mechanisms of fullerenols actions.

Maternal preconceptional and prenatal exposure to El Niño Southern Oscillation levels and child mortality: a multi-country study

El Niño Southern Oscillation (ENSO) has been shown to relate to the epidemiology of childhood infectious diseases, but evidence for whether they increase child deaths is limited. Here, we investigate the impact of mothers' ENSO exposure during and prior to delivery on child mortality by constructing a retrospective cohort study in 38 low- and middle-income countries. We find that high levels of ENSO indices cumulated over 0-12 lagged months before delivery are associated with significant increases in risks of under-five mortality; with the hazard ratio ranging from 1.33 (95% confidence interval [CI], 1.26, 1.40) to 1.89 (95% CI, 1.78, 2.00). Child mortality risks are particularly related to maternal exposure to El Niño-like conditions in the 0th-1st and 6th-12th lagged months. The El Niño effects are larger in rural populations and those with unsafe sources of drinking water and less education. Thus, preventive interventions are particularly warranted for the socio-economically disadvantaged.

Reconsider the burn: The transient effect of a chlorine burn on controlling opportunistic pathogens in a full-scale chloraminated engineered water system

Nitrification is a serious water-quality issue in chloraminated engineered water systems (EWSs). Nitrification is often remediated by a chlorine burn (i.e., a free‑chlorine conversion), a short-term switch from chloramination to chlorination in EWSs. Opportunistic pathogens (OPs) are the dominant infectious agents in EWSs. However, the responses of OPs to a chlorine burn are unknown. This study for the first time assessed how a chlorine burn affected OPs in a full-scale EWS. We determined the impact of a 1.5-month chlorine burn on four dominant OPs (Legionella, Mycobacterium, Pseudomonas, and Vermamoeba vermiformis) in a representative full-scale chloraminated EWS in the United States. Legionella and Mycobacterium were the most abundant OPs. In the water main, the summed concentration of the four OPs during the chlorine burn [3.27 ± 1.58 log10(GCN·L-1); GCN: genome or gene copy number] was lower (p ≤ 0.001) than before the burn [4.83 ± 0.50 log10(GCN·L-1)]. After the burn, the summed concentration increased to 4.27 ± 0.68 log10(GCN·L-1), comparable to before the burn (p > 0.05), indicating a transient effect of the chlorine burn in the water main. At the residential sites, the summed concentrations of the four OPs were comparable (p > 0.05) at 5.50 ± 0.84, 5.27 ± 1.44, and 5.08 ± 0.71 log10(GCN·L-1) before, during, and after the chlorine burn, respectively. Therefore, the chlorine burn was less effective in suppressing OP (re)growth in the premise plumbing. The low effectiveness might be due to more significant water stagnation and disinfectant residual decay in the premise plumbing. Indeed, for the entire sampling period, the total chlorine residual concentration in the premise plumbing (1.8 mg Cl2·L-1) was lower than in the water main (2.4 mg Cl2·L-1). Consequently, for the entire sampling period, the summed concentration of the four OPs in the premise plumbing [5.26 ± 1.08 log10(GCN·L-1)] was significantly higher (p < 0.001) than in the water main [4.04 ± 1.25 log10(GCN·L-1)]. In addition, the chlorine burn substantially increased the levels of disinfection by-products (DBPs) in the water main. Altogether, a chlorine burn is transient or even ineffective in suppressing OP (re)growth but raises DBP concentrations in chloraminated EWSs. Therefore, the practice of chlorine burns to control nitrification should be optimized, reconsidered, or even replaced.

Toxicological risk assessment using spring water quality indices in plateaus of Giresun Province/Türkiye: a holistic hydrogeochemical data analysis

Water scarcity is a growing concern due to rapid urbanization and population growth. This study assesses spring water quality at 20 stations in Giresun province, Türkiye, focusing on potentially toxic elements and physicochemical parameters. The Water Quality Index rated most samples as "excellent" during the rainy season and "good" during the dry season, except at stations 4 (40° 35' 12″ North/38° 26' 34″ East) and 19 (40° 44' 28″ North/38° 06' 53″ West), indicating "poor" quality. Mean macro-element concentrations (mg/L) were: Ca (34.27), Na (10.36), Mg (8.26), and K (1.48). Mean trace element values (μg/L) were: Al (1093), Zn (110.54), Fe (67.45), Mn (23.03), Cu (9.79), As (3.75), Ni (3.00), Cr (2.84), Pb (2.70), Co (1.93), and Cd (0.76). Health risk assessments showed minimal non-carcinogenic risks, while carcinogenic risk from arsenic slightly exceeded safe limits (CR = 1.75E-04). Higher arsenic concentrations during the rainy season were due to increased recharge, arsenic-laden surface runoff, and human activities. Statistical analyses (PCA, PCC, HCA) suggested that metals and physico-chemical parameters originated from lithogenic, anthropogenic, or mixed sources. Regular monitoring of spring water is recommended to mitigate potential public health risks from waterborne contaminants.

The impact of water pollution on the health of older people

Water pollution exerts a negative impact on the health of both women and men, inducing hormonal changes, accelerating aging, and consequently leading to the premature onset of age-related health problems. Water pollutants can in general be classified as chemical (both organic and inorganic), physical, and biological agents. Certain chemical pollutants have been found to disrupt hormonal balance by blocking, mimicking, or disrupting functions within the intricate homeostasis of the human body. Moreover, certain water pollutants, including specific pesticides and industrial chemicals, have been associated with neurological and psychiatric disorders, such as mood swings, depression, cognitive decline, and anxiety, impacting both women and men. Water pollution is also associated with physical ailments, such as diarrhea, skin diseases, malnutrition, and cancer. Exposure to specific pollutants may promote premature menopause and vasomotor symptoms, elevate the risk of cardiovascular disease, and reduce bone density. In men, exposure to water pollution has been shown to reduce LH, FSH, and testosterone serum levels. The oxidative stress induced by pollutants prompts apoptosis of Sertoli and germ cells, inhibiting spermatogenesis and altering the normal morphology and concentration of sperm. Environmental estrogens further contribute to reduced sperm counts, reproductive system disruptions, and the feminization of male traits. Studies affirm that men generally exhibit a lower susceptibility than women to hormonal changes and health issues attributed to water pollutants. This discrepancy may be attributed to the varied water-related activities which have traditionally been undertaken by women, as well as differences in immune responses between genders. The implementation of effective measures to control water pollution and interventions aimed at safeguarding and enhancing the well-being of the aging population is imperative. The improvement of drinking water quality has emerged as a potential public health effort with the capacity to curtail the onset of cognitive impairment and dementia in an aging population.

Application of artificial intelligence in modeling of nitrate removal process using zero-valent iron nanoparticles-loaded carboxymethyl cellulose

This study explores nitrate reduction in aqueous solutions using carboxymethyl cellulose loaded with zero-valent iron nanoparticles (Fe0-CMC). The structures of this nano-composite were characterized using various techniques. Based on the characterization results, the specific surface area of Fe0-CMC measured by the Brunauer-Emmett-Teller analysis were 39.6 m2/g. In addition, Scanning Electron Microscopy images displayed that spherical nano zero-valent iron particles (nZVI) with an average particle diameter of 80 nm are surrounded by carboxymethyl cellulose and no noticeable aggregates were detected. Batch experiments assessed Fe0-CMC's effectiveness in nitrate removal under diverse conditions including different adsorbent dosages (Cs, 2-10 mg/L), contact time (t, 10-1440 min), initial pH (pHi, 2-10), temperature (T, 10-55 °C), and initial concentration of nitrate (C0, 10-500 mg/L). Results indicated decreased removal with higher initial pHi and C0, while increased Cs and T enhanced removal. The study of nitrate removal mechanism by Fe0-CMC revealed that the redox reaction between immobilized nZVI on the CMC surface and nitrate ions was responsible for nitrate removal, and the main product of this reaction was ammonium, which was subsequently completely removed by the synthesized nanocomposite. In addition, a stable deviation quantum particle swarm optimization algorithm (SD-QPSO) and a least square error method were employed to train the ANFIS parameters. To demonstrate model performance, a quadratic polynomial function was proposed to display the performance of the SD-QPSO algorithm in which the constant parameters were optimized through the SD-QPSO algorithm. Sensitivity analysis was conducted on the proposed quadratic polynomial function by adding a constant deviation and removing each input using two different strategies. According to the sensitivity analysis, the predicted removal efficiency was most sensitive to changes in pHi, followed by Cs, T, C0, and t. The obtained results underscore the potential of the ANFIS model (R2 = 0.99803, RMSE = 0.9888), and polynomial function (R2 = 0.998256, RMSE = 1.7532) as accurate and efficient alternatives to time-consuming laboratory measurements for assessing nitrate removal efficiency. These models can offer rapid insights and predictions regarding the impact of various factors on the process, saving both time and resources.

The effect of carbonized zeolitic imidazolate framework-67 (ZIF-67) support on the reactivity and selectivity of bimetal-catalytic aqueous NO3- reduction

A metallic catalyst, Cobalt N-doped Carbon (Co@NC), was obtained from Zeolitic-Imidazolate Framework-67 (ZIF-67) for efficient aqueous nitrate (NO3-) removal. This advanced catalyst indicated remarkable efficiency by generating valuable ammonium (NH3/NH4+) via an environmentally friendly production technique during the nitrate treatment. Among various metals (Cu, Pt, Pd, Sn, Ru, and Ni), 3.6%Pt-Co@NC exhibited an exceptional nitrate removal, demonstrating a complete removal of 60 mg/L NO3--N (265 mg/L NO3-) in 30 min with the fastest removal kinetics (11.4 × 10-2 min-1) and 99.5% NH4+ selectivity. The synergistic effect of bimetallic Pt-Co@NC led to 100% aqueous NO3- removal, outperforming the reactivity by bare ZIF-67 (3.67%). The XPS analysis illustrated Co's promotor role for NO3- reduction to less oxidized nitrogen species and Pt's hydrogenation role for further reduction to NH4+. The durability test revealed a slight decrease in NO3- removal, which started from the third cycle (95%) and slowly proceeded to the sixth cycle (80.2%), while NH4+ selectivity exceeded 82% with no notable Co or Pt leaching throughout seven consecutive cycles. This research shed light on the significance of the impregnated Pt metal and Co exposed on the Co@NC surface for the catalytic nitrate treatment, leading to a sustainable approach for the effective removal of nitrate and economical NH4+ production.

Towards a zero liquid discharge process from brine treatment: Water recovery, nitrate electrochemical elimination and potential valorization of hydrogen and salts

This research addresses the issues related with treatment and valorization of brines and nitrate decontamination of surface and ground waters. The objective was to approximate to zero liquid discharge (ZLD) minimizing the environmental impact of brines of an electrodialysis reversal water treatment plant (EDRWTP) as an example. The innovative in flow process was developed from lab to pre-industrial scale and joined several main concepts: ion-exchange equilibrium for softening or demineralization of brines; reversed osmosis to recover suitable water and to enrich the waste in nitrate for efficient electrochemical reduction of NO3- to N2; valorization of subproducts by direct use or by precipitation; and assessment of the whole process by measuring in-line several parameters. The achieved softening was around 98 % and the recovered water from this current by reversed osmosis was 75 %. The brine of this step (25 %) contained around 1500 mg/L of nitrate and it was treated by electrochemical reduction with a Bi/Sn cathode providing a gas current of 60 % of initial nitrate reduced to N2, O2, H2O, NH3 and at least 97 % of H2. The aqueous current contained around 40 % of initial nitrate as ammonium and nitrite lower than 50 and 5 mg/L, respectively. Hypochlorite was added to this last current for oxidizing ammonium and nitrite to N2 and nitrate, respectively, being nitrate and ammonium lower than 50 and 5 mg/L, respectively. After the obtained water was demineralized and conducted to the EDRWTP inlet. The recovery of insoluble salts as calcium carbonate, reuse of saline solutions for the regeneration of process resins and the potential use of hydrogen generated as a by-product during the electrochemical reduction are other possible utilities.

Chemoprophylaxis of precancerous lesions in patients who are at a high risk of developing colorectal cancer (Review)

The diagnostics of colorectal cancer (CRC) and precancerous lesions in the colon is one of the most urgent matters to be considered for the modern protocols of complex examination, recommended for use from the age of 45 years, and including both instrumental and laboratory methods of research: Colonoscopy, CT colonography, flexible sigmoidoscopy, fecal occult blood test, fecal immunohistochemistry test and stool DNA test Nevertheless, the removal of those precancerous lesions does not solve the issue, and, apart from the regular endoscopic monitoring of patients who are at a high risk of developing CRC, the pharmacological treatment of certain key pathogenic mechanisms leading to the development of CRC is required. The present review to discusses the function of β-catenin in the transformation of precancerous colorectal lesions into CRC, when collaborating with PI3K/AKT/mTOR signaling pathway and other mechanisms. The existing methods for the early diagnostics and prevention of discovered anomalies are described and categorized. The analysis of the approaches to chemoprophylaxis of CRC, depending on the results of endoscopic, morphological and molecular-genetic tests, is presented.

Acyltransferase zinc finger DHHC-type containing 2 aggravates gastric carcinoma growth by targeting Nrf2 signaling: A mechanism-based multicombination bionic nano-drug therapy

The significant regulatory role of palmitoylation modification in cancer-related targets has been demonstrated previously. However, the biological functions of Nrf2 in stomach cancer and whether the presence of Nrf2 palmitoylation affects gastric cancer (GC) progression and its treatment have not been reported. Several public datasets were used to look into the possible link between the amount of palmitoylated Nrf2 and the progression and its outcome of GC in patients. The palmitoylated Nrf2 levels in tumoral and peritumoral tissues from GC patients were also evaluated. Both loss-of-function and gain-of-function via transgenic experiments were performed to study the effects of palmitoylated Nrf2 on carcinogenesis and the pharmacological function of 2-bromopalmitate (2-BP) on the suppression of GC progression in vitro and in vitro. We discovered that Nrf2 was palmitoylated in the cytoplasmic domain, and this lipid posttranslational modification causes Nrf2 stabilization by inhibiting ubiquitination, delaying Nrf2 destruction via the proteasome and boosting nuclear translocation. Importantly, we also identify palmitoyltransferase zinc finger DHHC-type palmitoyltransferase 2 (DHHC2) as the primary acetyltransferase required for the palmitoylated Nrf2 and indicate that the suppression of Nrf2 palmitoylation via 2-bromopalmitate (2-BP), or the knockdown of DHHC2, promotes anti-cancer immunity in vitro and in mice model-bearing xenografts. Of note, based on the antineoplastic mechanism of 2-BP, a novel anti-tumor drug delivery system ground 2-BP and oxaliplatin (OXA) dual-loading gold nanorods (GNRs) with tumor cell membrane coating biomimetic nanoparticles (CM@GNRs-BO) was established. In situ photothermal therapy is done using near-infrared (NIR) laser irradiation to help release high-temperature-triggered drugs from the CM@GNRs-BO reservoir when needed. This is done to achieve photothermal/chemical synergistic therapy. Our findings show the influence and linkage of palmitoylated Nrf2 with tumoral and peritumoral tissues in GC patients, the underlying mechanism of palmitoylated Nrf2 in GC progression, and novel possible techniques for addressing Nrf2-associated immune evasion in cancer growth. Furthermore, the bionic nanomedicine developed by us has the characteristics of dual drugs delivery, homologous tumor targeting, and photothermal and chemical synergistic therapy, and is expected to become a potential platform for cancer treatment.

Assessing groundwater denitrification spatially is the key to targeted agricultural nitrogen regulation

Globally, food production for an ever-growing population is a well-known threat to the environment due to losses of excess reactive nitrogen (N) from agriculture. Since the 1980s, many countries of the Global North, such as Denmark, have successfully combatted N pollution in the aquatic environment by regulation and introduction of national agricultural one-size-fits-all mitigation measures. Despite this success, further reduction of the N load is required to meet the EU water directives demands, and implementation of additional targeted N regulation of agriculture has scientifically and politically been found to be a way forward. In this paper, we present a comprehensive concept to make future targeted N regulation successful environmentally and economically. The concept focus is on how and where to establish detailed maps of the groundwater denitrification potential (N retention) in areas, such as Denmark, covered by Quaternary deposits. Quaternary deposits are abundant in many parts of the world, and often feature very complex geological and geochemical architectures. We show that this subsurface complexity results in large local differences in groundwater N retention. Prioritization of the most complex areas for implementation of the new concept can be a cost-efficient way to achieve lower N impact on the aquatic environment.

Long-term cancer and overall mortality associated with drinking water nitrate in the United States

OBJECTIVES

Nitrate is a probable carcinogen regulated in drinking water by the US Environmental Protection Agency (EPA) to a maximum contaminant level (MCL) of 10 mg/L nitrate-nitrogen (NO3-N; equivalent to 44.3 mg/L NO3). We aimed to determine the association of US drinking water nitrate levels with overall as well as cardiovascular, cancer, and other cause mortality.

STUDY DESIGN

This study used a population-based retrospective cohort design.

METHODS

We analyzed data from 2029 participants of the 2005-2006 National Health and Nutrition Examination Survey followed for mortality until 2019 for a median of 13.9 years. We used Cox proportional hazards regression to estimate the hazard ratio (HR) and 95% confidence interval (CI) for mortality associated with drinking water nitrate, adjusting for covariates that included socio-economic factors and pack-years of cigarette smoking.

RESULTS

Drinking water nitrate was detected in 50.8 % of the samples, had a median concentration of 0.77 mg/L NO3, and was above US EPA MCL in 0.4 % of participants. In adjusted analysis, drinking water nitrate detection was associated with 73 % higher cancer mortality (HR: 1.73, 95% CI: 1.19-2.51), whereas a 10-fold increase in drinking water nitrate levels was associated with 69 % higher cancer mortality (HR: 1.69, 95% CI: 1.24-2.31) and 21 % higher overall mortality (HR: 1.21, 95% CI: 1.00-1.46). Drinking water nitrate below EPA MCL was still associated with higher cancer mortality (HR: 1.61, 95% CI: 1.07-2.43 per 10-fold increase and HR: 1.61, 95% CI: 1.08-2.42 for detection).

CONCLUSIONS

Levels of drinking water nitrate may be an overlooked contributor to cancer mortality in the United States.

Ingested nitrate and nitrite and end-stage renal disease in licensed pesticide applicators and spouses in the Agricultural Health Study

BACKGROUND

Nitrate and nitrite ingestion has been linked to kidney cancer, possibly via the endogenous formation of carcinogenic N-nitroso compounds. These exposures might also contribute to end-stage renal disease (ESRD).

OBJECTIVES

We investigated associations of drinking water nitrate and dietary nitrate and nitrite intakes (total and by food type) with incident ESRD in the Agricultural Health Study. We also explored modifying effects of vitamin C and heme iron intake, which may affect endogenous nitrosation.

METHODS

We performed complete case analyses among private pesticide applicators and their spouses. We obtained water nitrate estimates for participants whose primary drinking water source at enrollment (1993-1997) was public water supplies (PWS) or private wells (N = 59,632). Average nitrate concentrations were computed from historical data for PWS users and predicted from random forest models for private well users. Analysis of dietary nitrate and nitrite was restricted to the 30,177 participants who completed the NCI Dietary History Questionnaire during follow-up (1999-2003). Incident ESRD through 2018 was ascertained through linkage with the U.S. Renal Data System. We estimated adjusted hazard ratios (HRs) and 95%CI for associations of tertiles (T) of exposure with ESRD overall and explored effects in strata of vitamin C and heme iron intake.

RESULTS

We identified 469 incident ESRD cases (206 for dietary analysis). Water nitrate and total dietary nitrate/nitrite were not associated with ESRD, but increased ESRD was associated with nitrate and nitrite from processed meats. We found apparent associations between nitrite and ESRD only among participants with vitamin C

SIGNIFICANCE

ESRD incidence was associated with dietary nitrate/nitrite from processed meat among all study participants and with total dietary nitrite among participants with lower vitamin C or higher heme iron intake.

IMPACT STATEMENT

There are few well-established environmental risk factors for end-stage renal disease (ESRD), a worldwide public health challenge. Ingestion of nitrate and nitrite, which may lead to endogenous formation of carcinogenic N-nitroso compounds, has been linked to some cancers and chronic diseases. We investigated these exposures in relation to ESRD in an agricultural cohort. ESRD incidence was associated with dietary nitrate/nitrite from processed meat and with total dietary nitrite among subgroups with lower vitamin C or higher heme iron intake. This study provides preliminary evidence that points to dietary nitrite and possibly dietary nitrate intake as a potential contributor to ESRD.

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Key Words

• Chronic kidney disease
• End-stage renal disease
• Nitrate
• Nitrite
• Processed meat
• Water pollution

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MESH Headings

• Humans
• Nitrates/analysis
• Kidney Failure, Chronic/epidemiology
• Kidney Failure, Chronic/chemically induced
• Male
• Nitrites/analysis
• Nitrites/adverse effects
• Female
• Middle Aged
• Spouses/statistics & numerical data
• Adult
• Pesticides
• Occupational Exposure/adverse effects
• Occupational Exposure/analysis
• Aged
• Drinking Water/chemistry
• Drinking Water/analysis
• Incidence
• Agriculture
• Diet/statistics & numerical data
• Farmers/statistics & numerical data
• Ascorbic Acid

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Affiliation(s)

Dazhe Chen Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
Christine G Parks Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
Laura E Beane Freeman Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
Jonathan N Hofmann Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
Rashmi Sinha Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
Jessica M Madrigal Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
Mary H Ward Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
Dale P Sandler Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA.

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Collaborators Collapse

Synthesis and DFT calculation of microbe-supported Pd nanocomposites with oxidase-like activity for sensitive detection of nitrite

Nanozymes have emerged as the forefront of research in analytical sensing due to their promising applications. In this study, we utilized polyethyleneimine (PEI)-modified Pichia pastoris residue to synthesize microbial-based palladium nanocomposites (Pd/MMR) through simple in-situ reduction methods. The dispersed active sites of Pd nanoparticles with a size of 2.12 ± 0.49 nm that were supported by microbial biomass provided excellent oxidative enzyme-mimicking activity to Pd/MMR. The catalytic mechanism of Pd/MMR involved the combined action of 1O2, ·OH, and ·O2-, and possible reaction pathways and corresponding energy barriers were also revealed using DFT calculations. We also established a quantitative detection platform for nitrite using Pd/MMR. The platform could detect nitrite at concentrations of 10-300 μM with a detection limit of 0.27 μM, and was successfully applied to detect nitrite in real samples. These findings serve as a reference for the synthesis and application of metal nanocomposites using microorganisms.

Sustainable conversion of alkaline nitrate to ammonia at activities greater than 2 A cm-2

Nitrate (NO3‒) pollution poses significant threats to water quality and global nitrogen cycles. Alkaline electrocatalytic NO3‒ reduction reaction (NO3RR) emerges as an attractive route for enabling NO3‒ removal and sustainable ammonia (NH3) synthesis. However, it suffers from insufficient proton (H+) supply in high pH conditions, restricting NO3‒-to-NH3 activity. Herein, we propose a halogen-mediated H+ feeding strategy to enhance the alkaline NO3RR performance. Our platform achieves near-100% NH3 Faradaic efficiency (pH = 14) with a current density of 2 A cm-2 and enables an over 99% NO3--to-NH3 conversion efficiency. We also convert NO3‒ to high-purity NH4Cl with near-unity efficiency, suggesting a practical approach to valorizing pollutants into valuable ammonia products. Theoretical simulations and in situ experiments reveal that Cl-coordination endows a shifted d-band center of Pd atoms to construct local H+-abundant environments, through arousing dangling O-H water dissociation and fast *H desorption, for *NO intermediate hydrogenation and finally effective NO3‒-to-NH3 conversion.

Water Quality and Associated Human Health Risk Assessment Related to Some Ions and Trace Elements in a Series of Rural Roma Communities in Transylvania, Romania

This research aims to assess the content of some ions and trace elements in water sources in 24 rural Roma communities in Transylvania in order to assess the human health risk associated with exposure to such elements and ions. To this end, eight ions (F-, Cl-, Br-, NO2-, NO3-, SO42-, PO43-, NH4+) and ten trace elements (Cr, Ni, As, Pb, Cd, Mn, Cu, Zn, Fe, and Hg) were determined in 71 water samples by ion chromatography coupled with a conductivity detector for ions and atomic absorption spectrophotometry for all trace elements. General parameters were also determined. Non-conformity (as number of samples), according to the EU Drinking Water Directive, was observed as follows: pH (7), EC (7), hardness (1), oxidizability (15), Cl- (4), NO3- (30), SO42- (6), Fe (16), Mn (14), As (3), and Ni (1 sample). The incidence of ions was Cl- (71), SO42- (70), F- (67), NO3- (65), NH4+ (21), Br- (10), PO43-, and NO2- (1 sample) and for trace elements, Mn (59), Fe (50), As (38), Ni (32), Cu (29), Zn (28), Cd (12), Cr (11), and Pb (3 samples). Hg was not detected. Non-carcinogenic (HI) values exceeded one for As in 13 Roma communities, with higher values for children than for adults. For NO3-, the HI values were >1 in 12 for adults and 14 communities for children. The carcinogenic risk (CR) for As through ingestion ranged from 0.795 to 3.50 × 10-4 for adults and from 1.215 to 5.30 × 10-4 for children. CR by dermal contact was in the range of ×10-6 both for adults and children.