Arsenic (As) is a potent carcinogen that enters the human food chain mainly through rice, which is one of the staple food crops worldwide. During February 2022, a market survey was conducted and 500 samples of rice grains were collected across 41 different locations in Mumbai/Navi-Mumbai. On the basis of grain As-accumulation, samples were grouped into three categories including low- (0-30 ng g-1 DW), medium- (31-70 ng g-1 DW) or high- (>71 ng g-1 DW). The health risk assessment revealed that a significant proportion of samples under the mid-As category with As-level below WHO permissible limit of 100 ng g-1 DW, have hazard quotient > 1, indicating significant risk considering the dietary intake of 400 g rice/day. Further, a combination of parboiling and absorption-based traditional Indian cooking method was found effective in significantly reducing As-accumulation by ∼0.4-fold, in lieu of marginal dietary supplement of essential nutrients like iron and manganese. The extracts of Kolam rice significantly increased the levels of reactive-oxygen species (ROS) and reduced glutathione (GSH) in murine lymphocytes, compared those grown on As-free soil, indicating redox imbalance. Taken together, the findings supported that "linear-no-threshold" concept should be followed for evaluating toxicity of As-contaminated rice grains, to be safe or unsafe for human consumption.

Mitigation of potentially toxic elements (PTEs) such as uranium (U) and arsenic (As), and fulfilment of global food demand requires a sustainable approach. Therefore, a multiple PTE-tolerant Methylobacterium sp. EIKU22 was explored for its bioremediation and biofertilization potential. This multi-metal tolerant isolate removed 29.88% U (initial dose: 100 mg L-1, pH 4.0, biosorption 3.74 mg g-1) after 14 days, following pseudo-second-order (PSO) kinetics. The isolate also showed 54% As(III) [pseudo-first-order kinetic; 3.72 mg g-1]; and ~ 37% As(V) (PSO; 2.4 mg g-1) removal within 60 min with the same initial dosing of either As(III) or As(V). Moreover, the strain precipitated > 96.5% and ~ 97% of U using released phosphate from inorganic and organic sources, respectively. Further analysis with inorganic phosphate showed > 31%, > 41% and > 98% of U precipitation from initial doses of 1000, 500 and 100 mg L-1 within 5 min. Methylobacterium sp. EIKU22 expresses the potential to solubilize ~ 178% phosphate, 169.8% potassium, 156-213% zinc within 6 days, and was able to withstand a pH range of 4.0-8.0, temperature range of 20-35 °C, and exhibited resilience to up to 10% NaCl exposure despite being affected by UV exposure. Further, the isolate showed to grow in nitrogen-free media and produce IAA, ammonia, siderophore, ACC deaminase, cellulase and catalase, suggesting potential application in plant growth promotion. The isolate harbours amoA, and nifH genes and imparts better survivability and vegetative growth in the rice seedling. These findings showcase the strain's dual applicability. However, further investigation is needed to generalize the findings.

This study was conducted in 2022 to investigate the water variables of fountains used by people for drinking purposes in Şarkışla (Sivas, Türkiye). Five stations were selected from the most frequently used fountains. Sampling was carried out seasonally. Various physicochemical variables such as water temperature (WT), pH, electirical conductivity (EC), dissolved oxygen (DO), nitrite (NO2), nitrate (NO3), phosphate (PO4), sulphate (SO4), magnesium (Mg), calcium (Ca), total hardness (TH), chloride (Cl), salinity, total dissolved solids (TDS), arsenic (As), cadmium (Cd), zinc (Zn), manganese (Mn), and copper (Cu) were investigated. Additionally, the Nitrate Pollution Index (NPI), Groundwater Quality Index (GWQI), and Human Health Risk Assesment (HHRA) methods were applied to the data. One of the main objectives of this study was to conduct health risk assessments for people using water from drinking fountains and to identify both carcinogenic and non-carcinogenic metals. As a result of this research, NPI values indicated slight contamination, while no contamination was found based on GWQI values. The Mn and Cd were found to slightly exceed the permissible limit values. As, which exceeds the limit value in water, was found to pose a serious carcinogenic risk (CR) for both children and adults. High As values are from quaternary alluvial deposits and aquifer layers of Pliocene terrestrial layers. Considering the hazard quotient (HQ) and hazard index (HI) for the presence of Cd, it was determined that it poses a serious risk to humans and children through both ingestive and dermal exposure. At the end of the study, several recommendations for the sustainable use of drinking fountains water were provided.

The adsorption and oxidation of arsenite [As(III)] by soil components are critical processes that influence its toxicity and mobility. However, the specific mechanisms driving the synergistic interactions among bacteria, soil minerals, and humic acid (HA) in these processes remain insufficiently understood. This study investigated the effects of goethite and HA association on As(III) adsorption-oxidation by the As(III)-oxidizing bacterium SY8 using batch incubation experiments and spectroscopic analyses. The results indicated that goethite inhibited the growth of SY8, but its binary and ternary composites with HA and SY8 substantially enhanced the adsorption and oxidation of As(III) compared to SY8 alone. This enhancement could be attributed to the generation of hydroxyl radicals (·OH) through Fenton-like reactions that contribute to the enhanced oxidation of As(III). The Fenton-like reactions involved interactions between H2O2 and goethite, as well as the activation of molecular O2 by structural Fe(II). Furthermore, the proportion of As(V) associated with the solids was lower than that in the solution, suggesting that As(III) oxidation by SY8 was potentially inhibited by As(III) adsorption on goethite. Additionally, HA did not affect SY8 growth or its As(III) oxidation capability, but slightly enhanced As adsorption on the composites. These findings reveal a complex interplay among microbial, mineral, and organic matter interactions. Understanding these interactions is essential for elucidating soil As biogeochemical processes and developing effective remediation strategies for As-contaminated environments.

Arsenic is a widespread environmental carcinogen, and its carcinogenic mechanism has been the focus of toxicology. N6-methyladenosine (m6A) binding protein YTH domain family protein 2 (YTHDF2) performs various biological functions by degrading m6A-modified mRNAs. However, the m6A-modified target mRNA of YTHDF2 in regulating arsenic carcinogenesis remains largely unknown. To explore the effect of YTHDF2 in regulating arsenic carcinogenicity, we exposed the human keratinocyte HaCaT cells to 1 μM sodium arsenite for 50 generations to create a cell model of arsenic carcinogenesis (HaCaT-T). Our results demonstrated that YTHDF2 protein levels were higher in HaCaT-T cells than HaCaT cells, and knockdown of YTHDF2 significantly inhibited arsenic-induced malignant phenotypes. In addition, m6A levels in HaCaT-T cells were remarkably elevated, accompanied by abnormal expression of m6A methyltransferases and m6A demethylases. Mechanistically, YTHDF2 bound to p53-induced death domain protein 1 (PIDD1) mRNA in an m6A-dependent manner, thereby promoting the degradation of PIDD1 mRNA. Moreover, the decay of PIDD1 mRNA inhibited the formation of PIDDosome complex that is essential for activating the apoptosis initiator caspase-2, leading to a decrease in caspase-2-dependent mitochondrial apoptosis and subsequently promoting the malignant phenotypes of HaCaT-T cells. Collectively, our study reveals the role of YTHDF2 in arsenic-induced malignant phenotypes of human keratinocytes through direct interaction with PIDD1 mRNA in an m6A-dependent manner, which provides new insight into the precise mechanism underlying arsenic-induced skin cancer.

AS3MT, GSTO2, and GSTP1 genes play important roles in the arsenic biotransformation pathway, while CYP2E1 gene has a prominent role in the metabolic activation of xenobiotics. Hence, polymorphisms of these genes might have an effect on arsenic biotransformation and could impact susceptibility to arsenical skin lesions in individuals of chronic arsenic toxicity. The present case-control study, comprising 148 subjects, attempted to evaluate genetic association between nine polymorphisms of AS3MT, GSTO2, GSTP1 and CYP2E1 genes and arsenical skin lesions in a West Bengal (WB) population. A statistically significant association was found between rs11191439 (AS3MT) and arsenical skin lesions (OR = 5.50, P-value = 0.01) using logistic regression with age and gender as covariates. Among non-genetic risk factors, age and groundwater arsenic were found to be significantly associated with skin lesions (P-value < 0.05). When haplotypes among the intragenic polymorphisms of AS3MT, CYP2E1 and GSTO2 genes were analyzed, 'ATA' and 'ACG' haplotypes of the AS3MT gene showed significant difference between the case and control. Multifactor dimensionality reduction (MDR) analysis was performed on the nine polymorphisms and groundwater and urinary arsenic for studying gene-environment interactions. Strong association was observed between groundwater arsenic and skin lesions relative to the SNPs (P-value < 10-5). The best model with maximum testing accuracy included one SNP from the AS3MT (rs11191439) and groundwater arsenic (P-value < 0.0001). The present study documents the first report about the association of AS3MT gene variant with skin lesions in an arsenic exposed population of WB. Presumably, this is also the first study that has used MDR to investigate gene-environment interactions in arsenic-induced toxicity.

While groundwater is commonly perceived as safe, the excessive presence of trace metals, particularly arsenic (As), can pose significant health hazards. This review examines the current scenario of pollutants and their mitigations focusing on As contamination in groundwater across multiple nations, with a specific emphasis on the Indian Peninsula. Arsenic pollution surpasses the WHO limit of 10 ppb in 107 countries, impacting around 230 million people worldwide, with a substantial portion in Asia, including 20 states and four union territories in India. Analysis of the correlation between the aquifer and arsenic poisoning highlights severe contamination in groundwater originating from loose sedimentary aquifer strata, particularly in recently formed mountain ranges with geological sources presumed to contribute over 90% of arsenic pollution, i.e. a big environmental challenge. A myriad of techniques, including chromatographic, electrochemical, biological, spectroscopic, and colorimetric methods among others, are available for the detection and removal of arsenic from groundwater. Removal strategies encompass a wide array of approaches such as bioremediation, adsorption, coagulation/flocculation, ion exchange, biological processes, membrane treatment, and oxidation techniques specifically tailored for affected areas. Constructed wetlands help to eliminate heavy metal impurities such as As, Zn, Cd, Cu, Ni, Fe, and Cr. Their efficiency is influenced by design and environmental factors. Nanotechnology and nanoparticles have recently been studied to remove arsenic and toxic metal ions from water. Cost-effective solutions including community-based mitigation initiatives, alongside policy and regulatory frameworks addressing arsenic contamination, are essential considerations.

Arsenic in drinking water has been associated with an increased risk of health concerns. This metalloid is ingested and distributed throughout the body, accumulating in several organs, including the testis. In this organ, arsenic disturbs steroidogenesis and spermatogenesis and affects male fertility. Although testicular impairment induced by arsenic is well documented, it is still controversial whether such disturbance remains days after the removal of arsenic insult. Therefore, we used a meta-analytical approach to evaluate the magnitude of arsenic effects on testicular parameters and verify whether a withdrawal period can mitigate these alterations. The search terms 'testis" and 'arsenic' were used in PubMed/Medline, Scopus, and Web of Science databases. A total of 1,217 articles were obtained from the literature search, and 73 articles were included in this meta-analysis. Our results showed that arsenic negatively affected hormone synthesis and secretion, testicular weight, tubular and intertubular morphometry, and daily sperm production 24 h after ending exposure. Arsenic inhibited antioxidant enzyme activity, culminating in high oxidative metabolite production and apoptosis occurrence. Most of these effects were not observed in the testis between eight and fifty days after arsenic withdrawal, remaining endocrine dysregulation and oxidative metabolite production. Sodium arsenite was the most toxic compound to the testis at subchronic exposure. These findings shed light on the plasticity and regenerative capacity of testicular interstitium and spermatogonial stem cell niche. However, sexual hormone imbalance remained after arsenic removal. This review evidenced the importance of understanding its toxicity's short- and long-term effects on male reproductive competence.

Arsenic has been ranked as the most hazardous substance by the U.S. Agency for Toxic Substances and Disease Registry. Environmental arsenic exposure-evoked health risks have become a vital public health concern worldwide owing to the widespread existence of arsenic. Multi-omics is a revolutionary technique to data analysis providing an integrated view of bioinformation for comprehensively and systematically understanding the elaborate mechanism of diseases.

This study aimed at uncovering the potential contribution of liver-microbiota-gut axis in chronic inorganic arsenic exposure-triggered biotoxicity in chickens based on multi-omics technologies.

Forty Hy-Line W-80 laying hens were chronically exposed to sodium arsenite with a dose-dependent manner (administered with drinking water containing 10, 20, or 30 mg/L arsenic, respectively) for 42 d, followed by transcriptomics, serum non-targeted metabolome, and 16S ribosomal RNA gene sequencing accordingly.

Arsenic intervention induced a serious of chicken liver dysfunction, especially severe liver fibrosis, simultaneously altered ileal microbiota populations, impaired chicken intestinal barrier, further drove enterogenous lipopolysaccharides translocation via portal vein circulation aggravating liver damage. Furtherly, the injured liver disturbed bile acids (BAs) homoeostasis through strongly up-regulating the BAs synthesis key rate-limiting enzyme CYP7A1, inducing excessive serum total BAs accumulation, accompanied by the massive synthesis of primary BA-chenodeoxycholic acid. Moreover, the concentrations of secondary BAs-ursodeoxycholic acid and lithocholic acid were markedly repressed, which might involve in the repressed dehydroxylation of Ruminococcaceae and Lachnospiraceae families. Abnormal BAs metabolism in turn promoted intestinal injury, ultimately perpetuating pernicious circle in chickens. Notably, obvious depletion in the abundance of four profitable microbiota, Christensenellaceae, Ruminococcaceae, Muribaculaceae, and Faecalibacterium, were correlated tightly with this hepato-intestinal circulation process in chickens exposed to arsenic.

Our study demonstrates that chronic inorganic arsenic exposure evokes liver-microbiota-gut axis disruption in chickens and establishes a scientific basis for evaluating health risk induced by environmental pollutant arsenic.

Arsenic is associated with various neurological disorders, notably affecting memory and cognitive functions. The current study examined the protective effects of vitamin D3 (Vit. D3) in countering oxidative stress, neuroinflammation and apoptosis induced by sodium arsenite (SA) in the cerebral cortex of rats. Male Wistar rats were subjected to a daily oral administration of sodium arsenite (NaAsO2, SA) at a dosage of 5 mg/kg, along with 500 IU/kg of Vit. D3, and a combination of both substances for four weeks. The results indicated that Vit. D3 effectively mitigated the SA-induced increase in oxidative stress markers, thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO), the decrease in antioxidants (reduced glutathione; GSH, superoxide dismutase; SOD, catalase; CAT, and glutathione peroxidase; GPx), as well as the increase in pro-inflammatory markers including, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and amyloid-beta (Aβ)1-42. Furthermore, Vit. D3 reversed the alterations in the neurochemicals acetylcholinesterase (AchE), monoamine oxidase (MAO), dopamine (DA), and acetylcholine (Ach) and ameliorated the histopathological changes in the cerebral cortex. Moreover, immunohistochemical analyses revealed that Vit. D3 reduced the SA-induced overexpression of cerebral cysteine aspartate-specific protease-3 (caspase-3) and glial fibrillary acidic protein (GFAP) in the cerebral cortex of male rats. Consequently, the co-administration of Vit. D3 can protect the cerebral cortex against SA-induced neurotoxicity, primarily through its antioxidant, anti-inflammatory, anti-apoptotic, and anti-astrogliosis effects.

Present study aimed to identify arsenic (As)-resistant bacterial strains that can be used to mitigate arsenic stress. A bacterium Bacillus mycoides NR5 having As tolerance limit of 1100 mg L-1 was isolated from Nag River, Maharashtra, India. It was also equipped with plant growth-promoting (PGP) attributes like phosphate solubilization, siderophores, ammonia, and nitrate reduction, with added antibiotic tolerance. Furthermore, scanning electron microscopy (SEM) and transmission electron micrograph (TEM) suggested biosorption as possible mechanisms of arsenic tolerance. A strong peak in FTIR spectra at 3379.0 corresponding to amine in As-treated NR5 also indicated metal interaction with cell surface protein. Amplification of arsenic reductase gene in NR5 further suggested intracellular transformation of As speciation. Moreover, As tolerance capability of NR5 was shown in spinach plants in which the bacterium effectively mitigated 25 ppm As by producing defense-related proline molecules. Evidence from SEM, TEM, and FTIR, concluded biosorption possibly the primary mechanism of As tolerance in NR5 along with the transformation of arsenic. B. mycoides NR5 with PGP attributes, high As tolerance, and antibiotic resistance mediated enhanced As tolerance in spinach plants advocated that the strain can be a better choice for As bioremediation in contaminated agricultural soil and water.

Groundwater is an essential source of drinking as well as irrigation water. It has recently become a significant challenge to maintain good and safe drinking water for all living beings. The continuous supply of arsenic detected in groundwater poses a severe health problem and has adverse effects on humans and the ecosystem. Researchers also identified arsenic contamination globally across various regions. However, a few studies also identified that the groundwater of Patna, Saran, and Vaishali districts of Bihar is intoxicated by arsenic. To assess the toxic level of arsenic in groundwater, samples from various GPS-based pointed locations were collected from the study area using a GARMIN GPS device. The total concentration of arsenic in drinking water (mostly traces of arsenic, level of μg L-1 or less) can be detected only by sophisticated analytical techniques such as ICP-MS, GF-AAS, and HG-AAS. The standard procedures were followed to determine quality attributes in groundwater. Arsenic contamination persists in most areas and exceeds the permissible limits prescribed by the World Health Organization (WHO), negatively impacting the health of more than 10 million people in the state. The 90.47% and 85.71% groundwater samples of the study area exceeded the permissible limit of the WHO (0.01 mg L-1) and Bureau of Indian Standards (BIS (0.05 mg L-1), respectively. The analyzed data was obtained, and variability was noticed in total arsenic concentrations ranging from 0.002 to 7.801 mg L-1, with a mean value of 0.87 mg L-1. Similarly, the water quality attribute like total dissolved solids were identified in 14.28% of samples, which crossed 201 to 1026 mg L-1, with a mean value of 375.33 mg L-1.

Heavy metal pollution in water sources has become a major worldwide environmental issue, posing a threat to aquatic ecosystems and human health. The pollution of the aquatic environment is increasing as a result of industrialization, climate change, and urban development. The sources of heavy metal pollution in water include mining waste, leachates from landfills, municipal and industrial wastewater, urban runoff, and natural events such as volcanism, weathering, and rock abrasion. Heavy metal ions are toxic and potentially carcinogenic. They can also buildup in biological systems and cause bioaccumulation even at low levels of exposure, heavy metals can cause harm to organs such as the nervous system, liver and lungs, kidneys and stomach, skin, and reproductive systems. There were various approaches tried to purify water and maintain water quality. The main purpose of this article was to investigate the occurrence and fate of the dangerous contaminants (Heavy metal and metalloids) found in domestic and industrial effluents. This effluent mixes with other water streams and is used for agricultural activities and other domestic activities further complicating the issue. It also discussed conventional and non-conventional treatment methods for heavy metals from aquatic environments. Conclusively, a pollution assessment of heavy metals and a human health risk assessment of heavy metals in water resources have been explained. In addition, there have been efforts to focus on heavy metal sequestration from industrial waste streams and to create a scientific framework for reducing heavy metal discharges into the aquatic environment.

Arsenic (As) contamination of surface water has become a global concern, especially for the third world countries, and it is imperative to develop advanced materials and an effective treatment method to address the issue. In this paper, iron doped ZIF-8@MXene (Fe-ZIF-8@MXene) was prepared as a potential adsorbent to effectively and simultaneously remove As(III/V) from wastewater. To investigate this, Fe-ZIF-8@MXene was characterized before and after the removal of mixed As(III/V). The results of Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), specific surface area (BET) and point of zero charge (pHpzc) showed that Fe-ZIF-8@MXene was prepared successfully and kept a stable structure after As(III) and As(V) adsorption. The particle size of Fe-ZIF-8@MXene was in the range of 0.5 μm to 2.5 μm, where its BET was 531.7 m2/g. For both contaminants, adsorption was found to follow pseudo-second-order kinetics and was best-fitted by the Langmuir adsorption model with correlation coefficients (R2) of 0.998 and 0.997, for As(III) and As(V), respectively. The adsorbent was then applied to remove As from two actual water samples, giving maximum removal rates of 91.07% and 98.96% for As(III) and As(V), respectively. Finally, removal mechanisms for As(III/V) by Fe-ZIF-8@MXene were also explored. During the adsorption, multiple complexes were formed under the effect of its abundant surface functional groups involving multiple mechanisms, which included Van der Waals force, surface adsorption, chemical complexation and electrostatic interactions. In conclusion, this study demonstrated that Fe-ZIF-8@MXene was an advanced and reusable material for simultaneous removal of As(III/V) in wastewater.

The presence of high concentrations of arsenic (As) in agricultural soils and its subsequent accumulation in rice crop is a serious issue threatening sustainability of agriculture and human health. In the present work, remediation of As contaminated field in Nadia, West Bengal, India was done through the cultivation of Vetiver (Vetiveria zizanoides L. Nash) and the same field was subsequently used for rice (Oryza sativa L.) cultivation. The results showed that V. zizanoides could reduce As concentrations in the field to bring it lower than the maximum permissible limit (20 mg kg-1) in 11 months' time. The rice plants grown in remediated field showed improvement in growth and photosynthesis parameters as compared to that of contaminated field. Importantly, yield related parameters (filled seed, 1000 grain weight, number of panicles etc.) were also significantly higher in remediated field than that in contaminated field. Arsenic concentration in roots, shoot, husk and grains of rice was found to be significantly lower in remediated field than in contaminated field. Grain As decreased from 0.75 to 0.77 μg g-1 dw in contaminated field to 0.15-0.18 μg g-1 dw. In conclusion, replacing rice for single year with V. zizanoides crop can significantly remediate the field and can be a viable option.

Inorganic arsenic (iAs) is a well-recognized environmental pollutant that induces severe brain injury in humans and animals. The antioxidant, anti-inflammatory, and anti-ferroptotic effects of resveratrol (Res) were demonstrated in multiple animal experiments. In order to investigate the protective effect of Res on iAs-induced chicken brain injury, the 40 chickens (19-d-old, female) brain injury model was established by oral administration of iAs (30 mg/L NaAsO2) for 6 weeks. All chickens had free access to both food and water during the experiment. The biochemical indices, hematoxylin-eosin staining, and related protein levels of oxidative stress, inflammation and ferroptosis were then determined. Our results indicated that Res (1000 mg/kg) alleviated the iAs-induced brain injury after 6 weeks of oral administration, primarily by reducing the interleukin-1β mRNA expression and nuclear factor kappa B and malondialdehyde level, and increasing the antioxidant enzyme activity and the mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2). Taken together, our study demonstrates that Res effectively inhibits iAs-induced oxidative stress and ferroptosis by mediating the Nrf2 signaling pathway, thereby alleviating iAs-induced brain injury in chickens. This is the first time that the amelioration effects of Res on the iAs-induced brain have been investigated from multiple perspectives.

Replacement of water-intensive winter rice with strawberry (Fragaria × ananassa Duch.) may restrict groundwater extraction and improve water productivity and sustainability of agricultural production in the arsenic-contaminated Bengal basin. The potential of strawberry cultivation in terms of yield obtained and water use efficiency need to be evaluated under predominant soil types with mulch applications. Water-driven model AquaCrop was used to predict the canopy cover, soil water storage and above-ground biomass of strawberry in an arsenic-contaminated area in the Bengal basin. After successful calibration and validation over three seasons, AquaCrop was used over a range of management scenarios (nine drip-irrigation × three soil types × four mulch materials) to identify the best irrigation options for a drip-irrigated strawberry crop. The most appropriate irrigation of 176 mm for clay loam soil in lowland and 189 mm for sandy clay loam in medium land rice areas and the use of organic mulch from locally available jute agrotextile improved 1.4 times higher yield and 1.7 times higher water productivity than that of without mulch. Strawberry can be introduced as an alternative crop replacing rice in non-traditional upland and medium land areas of the arsenic-contaminated Bengal basin with 88% lower groundwater extraction load and better economic return to farmers.

The current study was designed to investigate the consequences of rice cooking and soaking of cooked rice (CR) with or without arsenic (As) contaminated water on As and Fe (iron) transfer to the human body along with associated health risk assessment using additive main-effects and multiplicative interaction (AMMI) and Monte Carlo Simulation model. In comparison to raw rice, As content in cooked rice (CR) and soaked cooked rice (SCR) enhanced significantly (at p < 0.05 level), regardless of rice cultivars and locations (at p < 0.05 level) due to the use of As-rich water for cooking and soaking purposes. Whereas As content in CR and SCR was reduced significantly due to the use of As-free water for cooking and soaking purposes. The use of As-free water (AFW) also enhanced the Fe content in CR. The overnight soaking of rice invariably enhanced the Fe content despite the use of As-contaminated water in SCR however, comparatively in lesser amount than As-free rice. In the studied area, due to consumption of As-rich CR and SCR children are more vulnerable to health hazards than adults. Consumption of SCR (prepared with AFW) could be an effective method to minimize As transmission and Fe enrichment among consumers.

Globally, more than 2 billion tonnes of municipal solid waste (MSW) are generated each year, with that amount anticipated to reach around 3.5 billion tonnes by 2050. On a worldwide scale, food and green waste contribute the major proportion of MSW, which accounts for 44% of global waste, followed by recycling waste (38%), which includes plastic, glass, cardboard, and paper, and 18% of other materials. Population growth, urbanization, and industrial expansion are the principal drivers of the ever-increasing production of MSW across the world. Among the different practices employed for the management of waste, landfill disposal has been the most popular and easiest method across the world. Waste management practices differ significantly depending on the income level. In high-income nations, only 2% of waste is dumped, whereas in low-income nations, approximately 93% of waste is burned or dumped. However, the unscientific disposal of waste in landfills causes the generation of gases, heat, and leachate and results in a variety of ecotoxicological problems, including global warming, water pollution, fire hazards, and health effects that are hazardous to both the environment and public health. Therefore, sustainable management of MSW and landfill leachate is critical, necessitating the use of more advanced techniques to lessen waste production and maximize recycling to assure environmental sustainability. The present review provides an updated overview of the global perspective of municipal waste generation, composition, landfill heat and leachate formation, and ecotoxicological effects, and also discusses integrated-waste management approaches for the sustainable management of municipal waste and landfill leachate.

Arsenic is an environmentally ubiquitous toxic metalloid. Chronic exposure to arsenic may lead to arsenicosis, while no specific therapeutic strategies are available for the arsenism patients. And Ginkgo biloba extract (GBE) exhibited protective effect in our previous study. However, the mechanisms by which GBE protects the arsenism patients remain poorly understood. A liquid chromatography-mass spectrometry (LC-MS) based untargeted metabolomics analysis was used to study metabolic response in arsenism patients upon GBE intervention. In total, 39 coal-burning type of arsenism patients and 50 healthy residents were enrolled from Guizhou province of China. The intervention group (n = 39) were arsenism patients orally administered with GBE (three times per day) for continuous 90 days. Plasma samples from 50 healthy controls (HC) and 39 arsenism patients before and after GBE intervention were collected and analyzed by established LC-MS method. Statistical analysis was performed by MetaboAnalyst 5.0 to identify differential metabolites. Multivariate analysis revealed a separation in arsenism patients between before (BG) and after GBE intervention (AG) group. It was observed that 35 differential metabolites were identified between BG and AG group, and 30 of them were completely or partially reversed by GBE intervention, with 14 differential metabolites significantly up-regulated and 16 differential metabolites considerably down-regulated. These metabolites were involved in promoting immune response and anti-inflammatory functions, and alleviating oxidative stress. Taken together, these findings indicate that the GBE intervention could probably exert its protective effects by reversing disordered metabolites modulating these functions in arsenism patients, and provide insights into further exploration of mechanistic studies.

The present study depicts the true failed scenario of the arsenic (As) removal units (ARU) in West Bengal by evaluating their treated water quality. Annual As removal efficiency of the 12 studied ARUs range between 35.2% and 82.6%. A comprehensive physico-chemical parameters and trace elements analysis find almost 25% and 16.7% of treated drinking water samples with poor water quality index (WQI) and high heavy metal evaluation index (HEI), respectively. The pond-based water treatment plant maintains the production of continuous As-safe water with a range between 60.2% and 66.7% due to its high Fe/As ratio. It's a discontent concluding the treated drinking water of the groundwater based-ARUs were observed with sufficient As mediated cancer risk (3 ×10-3). The non-cancer risk (HQ) of As is safe for the surface water treatment plant (0.38), whereas it is threatening for the groundwater based-ARUs (7.44). However, the drinking water samples are safe in view of HQ from the other trace elements like Hg, Al, Cd, Cr, Pb, F- and NO3-. Small scale ARU could be a feasible mitigation strategy in reducing the As menace in the long run if the plants are maintained correctly. Nevertheless, surface treated water is the most sustainable solution as withdrawal of groundwater for drinking purpose is not a viable practice.

Fe3+ complexed with 3-aminopropyltriethoxysilane (APTES)-modified carboxymethyl chitosan (CMC) named Fe-ACMC was synthesized by a one-step method at room temperature and pressure. The surface morphology and chemical structure of Fe-ACMC were characterized by SEM-EDS, XRD, BET, FT-IR, XPS, and ζ-potential. In batch adsorption, the optimum pH for arsenate [As(V)] adsorption onto Fe-ACMC was 3-9 with removal efficiency > 99%. The adsorption of As(V) could reach equilibrium within 25 min and the maximum adsorption capacity was 84.18 mg g-1. The pseudo-second-order model fitted well the kinetic data (R2 = 0.995), while the Freundlich model well described the adsorption isotherm of As(V) on Fe-ACMC (R2 = 0.979). The co-existing anions (NO3-, CO32-, and SO42-) exhibited a slight impact on the As(V) adsorption efficiency, whereas PO43- inhibited As(V) adsorption on Fe-ACMC. The real applicability of Fe-ACMC was achieved to remove ca. 10.0 mg L-1 of As(V) from natural waters to below 0.05 mg L-1. The regeneration and reuse of Fe-ACMC for As(V) adsorption were achieved by adding 0.2 mol L-1 HCl. The main adsorption mechanism of As(V) on Fe-ACMC was attributed to electrostatic attraction and inner-sphere complexation between -NH2···Fe3+ and As(V). In fixed-bed column adsorption, the Thomas model was the most suitable model to elucidate the dynamic adsorption behavior of As(V). The loading capacity of the Fe-ACMC packed column for As(V) was 47.04 mg g-1 at pH 7 with an initial concentration of 60 mg L-1, flow rate of 3 mL min-1, and bed height of 0.6 cm.

Significant aquifers around the world is contaminated by arsenic (As), that is regarded as a serious inorganic pollution. In this study, a biosorbent-based bio-filter column has been developed using two different plant biomasses (Colocasia esculenta stems and Artocarpus heterophyllus seeds) to remove total As from the aqueous system. Due to its natural origin, affordability, adaptability, removal effectiveness, and possibility for integration with existing systems, the biosorbent-based bio-filter column presents an alluring and promising method. It offers a practical and eco-friendly way to lessen the damaging impacts of heavy metal contamination on ecosystems and public health. In this system, As (III) is oxidized to As (V) using chlorine as an oxidant, after this post-oxidized As-contaminated water is passed through the bio-filter column to receive As-free water (or below World Health Organization permissible limit for As in drinking water). Optimization of inlet flow rate, interference of co-existing anions and cations, and life cycle of the column were studied. The maximum removal percent of As was identified to be 500 µg L-1 of initial concentration at a flow rate of 1.5 L h-1. Furthermore, the specifications of the biosorbent material was studied using elemental analysis and Zeta potential. The particle size distribution, morphological structures, and chemical composition before and after binding with As were studied using dynamic light scattering (DLS), scanning electron microscope-energy dispersive X-Ray spectroscopy (SEM-EDX), and fourier's transform infrared spectroscopy (FTIR) analysis, respectively. SuperPro 10 software was used to analyze the techno-economic viability of the complete unit and determine its ideal demand and potential. Life cycle assessment was studied to interpret the environmental impacts associated alongside the process system. Therefore, this bio-filtration system could have a potential application in rural, urban, and industrial sectors.

The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.

At a great many locations worldwide, the safety of drinking water is not assured due to pollution with arsenic. Arsenic toxicity is a matter of both systems chemistry and systems biology: it is determined by complex and intertwined networks of chemical reactions in the inanimate environment, in microbes in that environment, and in the human body. We here review what is known about these networks and their interconnections. We then discuss how consideration of the systems aspects of arsenic levels in groundwater may open up new avenues towards the realization of safer drinking water. Along such avenues, both geochemical and microbiological conditions can optimize groundwater microbial ecology vis-à-vis reduced arsenic toxicity.

As epigenetic modifications, lactylation and N6-methyladenosine (m6A) have attracted wide attention. Arsenite is an environmental pollutant that has been proven to induce idiopathic pulmonary fibrosis (IPF). However, the molecular mechanisms of lactylation and m6A methylation are unclear in arsenite-related IPF (As-IPF). In view of the limited understanding of molecular mechanism of m6A and lactylation in As-IPF, MeRIP-seq, RNA-seq and ChIP-seq were analyzed to verify the target gene regulated by m6A and H3K18 lactylation (H3K18la). We found that, for As-IPF, the global levels of m6A, levels of YTHDF1 and m6A-modified neuronal protein 3.1 (NREP) were elevated in alveolar epithelial cells (AECs). The secretion levels of TGF-β1 were increased via YTHDF1/m6A/NREP, which promoted the fibroblast-to-myofibroblast transition (FMT). Further, extracellular lactate from myofibroblasts elevated levels of the global lactylation (Kla) and H3K18la via the lactate monocarboxylate transporter 1 (MCT1), and, in AECs, H3K18la facilitated the transcription of Ythdf1. This report highlights the role of crosstalk between AECs and myofibroblasts via lactylation and m6A and the significance of H3K18la regulation of YTHDF1 in the progression of As-IPF, which may be useful for finding effective therapeutic targets.

Spatial and temporal variations have been found in the levels of arsenic (As) throughout the groundwater of the Ghaghara basin. Fifteen out of twenty-five districts in this basin are reported to be affected by As, where the levels of As in groundwater and soil exceed the permissible limits set by the WHO (10 μgl-1) and FAO (20 mgkg-1) respectively. These districts include a total of four municipalities in Nepal and eighty-six blocks in India, all of which have varying degrees of As contamination. Approximately 17 million people are at risk of As poisoning, with more than two orders of magnitude higher potential lifetime incremental cancer risk, constituting over 153 thousand potential additional cases of cancer due to As-contaminated drinking water. Out of the 90 As-contaminated blocks in the Ghaghara basin, 4 blocks have about 7-fold higher potential risk of developing cancer, 49 blocks have 8-37-fold higher risk, and 37 blocks have up to 375-fold higher risk compared to the upper limit of the USEPA acceptable range, which is 1 × 10-6-1 × 10-4. High accumulation of As has been reported in the nails, hair, and urine of local inhabitants, with higher levels observed in females than males. The toxicity of As is manifested in terms of a higher occurrence of various diseases. Reproductive endpoints, such as increased incidences of preterm birth, spontaneous abortion, stillbirth, low-birth weight, and neonatal death, have also been reported in the basin. The level of As in tube wells has been found to be negatively correlated with the depth (r = -0.906), and tube wells with high levels of As (>150 μgl-1) are generally located within close proximity (<10 km) to abandoned or present meander channels in the floodplain areas of the Ghaghara river. In addition to As contamination, the water quality index (WQI) in the Ghaghara basin is poor according to the BIS standards for drinking water. Groundwater in six out of fifteen districts is unsuitable for drinking purposes, with a WQI exceeding 100. The levels of As in agricultural soil in many villages of Ballia, Bahraich, and Lakhimpur Kheri districts have exceeded the FAO limit. Water from deep tube wells has been found to be relatively safe in terms of As content, and thus can be recommended for drinking purposes. However, the use of surface water needs to be encouraged for irrigation purposes in order to preserve soil health and reduce As contamination in the food chain, thereby minimizing the risk of cancer.

Arsenic (AS) is a metalloid element that widely exists and can cause different degrees of liver damage. The molecular mechanism of arsenic-induced liver injury has yet to be fully elucidated. Clinically, glutathione (GSH) is often used as an antidote for heavy metal poisoning and hepatoprotective drugs. However, the hepatoprotective effect of glutathione remains unknown in arsenic-induced liver injury. The regulatory relationship between Foxa2 and XIAP may play an important role in mitochondrial survival and death. Therefore, we took Foxa2-XIAP as the axis to explore the protective mechanism of GSH. In this study, we first established a mouse model of chronic arsenic exposure and examined liver function as reflected by quantitative parameters such as aspartate aminotransferase and alanine aminotransferase. Also, redox parameters in the liver were measured, including malondialdehyde, superoxide dismutase, 8-hydroxy-2'-deoxyguanosin, and glutathione peroxidase. RT-qPCR and western-blotting were used to detect the levels of related genes and proteins, such as Foxa2, XIAP, Smac, Bax, Bcl2, Caspase9, and Caspase3. Subsequently, GSH was administered at the same time as high arsenic exposure, and changes in the above parameters were observed. After a comprehensive analysis of the above results, we demonstrate that GSH treatment alleviates arsenic-induced oxidative stress and inhibits the mitochondrial pathway of apoptosis, which can be regulated through the Foxa2 and XIAP axis. The present study would be helpful in elucidating the molecular mechanism of arsenic-induced liver injury and identifying a new potential therapeutic target. And we also provided new theoretical support for glutathione in the treatment of liver damage caused by arsenic.

Groundwater is important for the survival of humanity and the demand for the same is drastically increasing globally. The precious water resources are under constant threat, either as a result of natural processes or due to the influence of the anthropogenic activities. Arsenic contamination of groundwater is one of those threats that have affected approximately over 500 million people in 107 countries globally. Although, many studies (∼1000 Nos.) have been carried out on arsenic hydrogeobiochemistry, only a few have reported, on the use of different isotopes in understanding the arsenic hydrochemistry, and its release mechanism and mobilization. Determination of the isotopic composition of a groundwater sample and its dissolved compounds enable a better insight into the hydrological processes that control the distribution and migration of arsenic in the subsurface hydrological system. The environmental isotopes of water molecules (δ18O and δ2H) have been widely used to assess the groundwater origin, its recharge mechanisms, the rock-water interactions and quality. The stable isotopes of dissolved compounds of water (δ34S, δ15N, δ13C, δ56Fe etc.) give better information on the reaction processes within these elements and thus act as a tracer for contaminants, while the radioactive isotopes, such as 14C, 3H, 81Kr, 36Cl, 39Ar etc., can be used to assess the residence time of groundwater and its renewability. This article reviews the different uses of environmental isotopes as tools for providing critical information on various hydrological processes in the arsenic contaminated regions that can't be obtained through conventional tools for better management of the groundwater resources.

Arsenic and cadmium in rice grain are of growing concern in the global food supply chain. Paradoxically, the two elements have contrasting behaviors in soils, making it difficult to develop a strategy that can concurrently reduce their uptake and accumulation by rice plant. This study examined the combined impacts of watering (irrigation) schemes, different fertilizers and microbial populations on the bioaccumulation of arsenic and cadmium by rice as well as on rice grain yield. Compared to drain-flood and flood-drain treatments, continuously flooded condition significantly reduced the accumulation of cadmium in rice plant but the level of arsenic in rice grain remained above 0.2 mg/kg, which exceeded the China national food safety standard. Application of different fertilizers under continuously flooded condition showed that compared to inorganic fertilizer and biochar, manure addition effectively reduced the accumulation of arsenic over three to four times in rice grain and both elements were below the food safety standard (0.2 mg/kg) while significantly increasing the rice yield. Soil Eh was the critical factor in the bioavailability of cadmium, while the behavior of arsenic in rhizosphere was associated with the iron cycle. The results of the multi-parametric experiments can be used as a roadmap for low-cost and in-situ approach for producing safe rice without compromising the yield.

Arsenic contamination in agricultural soils poses a serious health risk for humans. Bacteria that produce siderophores, primarily for iron acquisition, can be relevant in combating arsenic toxicity in agricultural soils and simultaneously act as biocontrol agents against plant diseases. We evaluated the arsenic bioremediation and biocontrol potential of the rhizosphere isolate Bacillus amyloliquefaciens BM3 and studied the interaction between the purified siderophore bacillibactin and arsenic.

BM3 showed high arsenic resistance [MIC value 475 and 24 mM against As(V) and As(III), respectively] and broad spectrum in-vitro antagonism against several phytopathogenic fungi. BM3 was identified by biochemical characterization and 16S rRNA gene sequencing. Scanning electron microscopy (SEM) analysis revealed increased cell size of BM3 when grown in presence of sub-lethal arsenic concentrations. Bioremediation assays showed a 74% and 88.1% reduction in As(V) and As(III) concentrations, respectively. Genetic determinants for arsenic resistance (arsC and aoxB) and antifungal traits (bacAB and chiA) were detected by PCR. Arsenic chelating ability of bacillibactin, the siderophore purified from culture filtrate of BM3 and identified through spectroscopic data analysis, was observed in CAS assay and fluorescence spectrometry. In-vivo application of talc-based formulation of BM3 in brinjal seedlings showed significant reduction in Fusarium wilt disease.

Strain B. amyloliquefaciens BM3 may be useful in arsenic bioremediation and may be considered for large field trials as an alternative to chemical fungicides by inhibiting soil borne pathogens.

Arsenic (As) is one of the most dangerous substances that can affect human health and long-term exposure to As in drinking water can even cause cancer. The objective of this study was to investigate the concentrations of total As in the blood of inhabitants of a Colombian region impacted by gold mining and to evaluate its genotoxic effect through DNA damage by means of the comet assay. Additionally, the concentration of As in the water consumed by the population as well as the mutagenic activity of drinking water (n = 34) in individuals were determined by hydride generator atomic absorption spectrometry and the Ames test, respectively. In the monitoring, the study population was made up of a group of 112 people, including inhabitants of four municipalities: Guaranda, Sucre, Majagual, and San Marcos from the Mojana region as the exposed group, and Montería as a control group. The results showed DNA damage related to the presence of As in blood (p < 0.05) in the exposed population, and blood As concentrations were above the maximum allowable limit of 1 μg/L established by the ATSDR. A mutagenic activity of the drinking water was observed, and regarding the concentrations of As in water, only one sample exceeded the maximum permissible value of 10 μg/L established by the WHO. The intake of water and/or food containing As is potentially generating DNA damage in the inhabitants of the Mojana region, which requires surveillance and control by health entities to mitigate these effects.

This study measured the concentrations of Hg, As, Ni, Cd, and Pb in six fish species commonly consumed in Kendari. Samples were bought within local markets from 2012 to 2017 at the end of the dry season. Results showed that mercury concentrations fluctuated between years and within species, except in the Caranx sexfasciatus, which showed no significant differences (Kruskall-Wallis, p-value > 0.05, df = 5) and an average concentration of 0.371 ± 0.162 µg g-1 DW. Arsenic was found in high concentrations across species and years and varied widely in C. sexfasciatus, the lowest value being 0.32 ± 0.01 µg g-1 DW in 2012 and the highest was 5.63 ± 1.89 µg g-1 DW in 2017. The highest nickel concentrations were found in 2016 across four of the six species. The fish samples displayed very low cadmium and lead concentrations throughout the study. In addition, the potential human health risk due to fish consumption was assessed. This showed that mercury is the only one of the five metals present in concentrations high enough to individually pose a potential hazard, the only metal likely to be accumulated beyond a safe concentration in Kendari. Chanos chanos never posed a toxicological risk based on the results of this research.

Deterioration of groundwater quality is a long-term incident which leads unending vulnerability of groundwater. The present work was carried out in Murshidabad District, West Bengal, India to assess groundwater vulnerability due to elevated arsenic (As) and other heavy metal contamination in this area. The geographic distribution of arsenic and other heavy metals including physicochemical parameters of groundwater (in both pre-monsoon and post-monsoon season) and different physical factors were performed. GIS-machine learning model such as support vector machine (SVM), random forest (RF) and support vector regression (SVR) were used for this study. Results revealed that, the concentration of groundwater arsenic compasses from 0.093 to 0.448 mg/L in pre-monsoon and 0.078 to 0.539 mg/L in post-monsoon throughout the district; which indicate that all water samples of the Murshidabad District exceed the WHO's permissible limit (0.01 mg/L). The GIS-machine learning model outcomes states the values of area under the curve (AUC) of SVR, RF and SVM are 0.923, 0.901 and 0.897 (training datasets) and 0.910, 0.899 and 0.891 (validation datasets), respectively. Hence, "support vector regression" model is best fitted to predict the arsenic vulnerable zones of Murshidabad District. Then again, groundwater flow paths and arsenic transport was assessed by three dimensions underlying transport model (MODPATH). The particles discharging trends clearly revealed that the Holocene age aquifers are major contributor of As than Pleistocene age aquifers and this may be the main cause of As vulnerability of both northeast and southwest parts of Murshidabad District. Therefore, special attention should be paid on the predicted vulnerable areas for the safeguard of the public health. Moreover, this study can help to make a proper framework towards sustainable groundwater management.

Groundwater is consumed by a large number of people as their primary source of drinking water globally. Among all the countries worldwide, nations in South Asia, particularly India and Bangladesh, have severe problem of groundwater arsenic (As) contamination so are on our primary focus in this study. The objective of this review study is to provide a viewpoint about the source of As, the effect of As on human health and agriculture, and available treatment technologies for the removal of As from water. The source of As can be either natural or anthropogenic and exposure mediums can either be air, drinking water, or food. As-polluted groundwater may lead to a reduction in crop yield and quality as As enters the food chain and disrupts it. Chronic As exposure through drinking water is highly associated with the disruption of many internal systems and organs in the human body including cardiovascular, respiratory, nervous, and endocrine systems, soft organs, and skin. We have critically reviewed a complete spectrum of the available ex situ technologies for As removal including oxidation, coagulation-flocculation, adsorption, ion exchange, and membrane process. Along with that, pros and cons of different techniques have also been scrutinized on the basis of past literatures reported. Among all the conventional techniques, coagulation is the most efficient technique, and considering the advanced and emerging techniques, electrocoagulation is the most prominent option to be adopted. At last, we have proposed some mitigation strategies to be followed with few long and short-term ideas which can be adopted to overcome this epidemic.

Arsenic (As) is a conspicuous contaminant, and exposure to this element through contaminated drinking groundwater poses a significant challenge to public health. Geogenic groundwater arsenic is associated with sedimentary setting. This work concentrates on the investigation of lithology, elemental abundance and mineralogical compositions about the arsenic profile and its effect to the groundwater from Huaihe River Basin, China. There are 90 sediment samples from the borehole at the field monitoring sites were collected and analyzed. The results reveal that sedimentary concentrations of As, Fe, Mn, S, Al, N, organic carbon and mineralogical compositions vary across the Quaternary aquifer. Arsenic abundance of sediments is 10.63 ± 0.56 mg/kg, and peak As concentrations occur between 59.0 m and 64.8 m in fine particle sediments. The specific higher As concentrations in sedimentary aquifer are concordant with arsenic-rich groundwater around the investigated borehole. Fe, Mn, and Al depth profiles follow similar tendency to those of As. Sedimentary As concentrations are significantly correlated to Fe, Al, and Mn concentrations, but are not correlated to organic carbon and S concentrations. Arsenic probably exists in the form of non-crystalline colloids, and Fe, Al minerals are potential host minerals for arsenic. Under alkaline conditions, groundwater arsenic is released and enriched within the Quaternary aquifer by reductive dissolution of As-hosting Fe and Al minerals.

Arsenic compounds are toxins that are widely distributed in the environment. Chronic exposure to low levels of these compounds can cause hepatic fibrosis and other damage. Th17 differentiation of CD4⁺ T cells and the secretion of IL-17 activates hepatic stellate cells (HSCs), which are involved in hepatic fibrosis, but their mechanisms in arsenic-induced hepatic fibrosis are unclear. We found, in arsenite-induced fibrotic livers of mice, increases of CD4⁺ T cell infiltration, Th17 cell nuclear receptor retinoic acid receptor-related orphan receptor γt (RORγt), and secretion of the pro-inflammatory cytokine IL-17. There were also elevated levels of the lncRNA, HOTAIR. For Jurkat cells, arsenite elevated levels of HOTAIR and protein levels of RORγt and IL-17A, decreased miR-17-5p, promoted Th17 cell differentiation, and released IL-17. The culture medium of arsenite-treated Jurkat cells activated LX-2 cells. Down-regulation of HOTAIR or up-regulation of miR-17-5p blocked arsenite-induced Th17 cell differentiation, which inhibited the LX-2 cell activation. However, down-regulation of HOTAIR and miR-17-5p reversed this inhibitory effect. For mice, silencing of HOTAIR diminished the hepatic levels of RORγt and IL-17A and alleviated arsenite-induced hepatic fibrosis. These results demonstrate that, for CD4⁺ T cells, arsenite promotes RORγt-mediated Th17 cell differentiation through HOTAIR down-regulation of miR-17-5p, and increases the secretion of cytokine IL-17A, which activates HSCs; the activated HSCs facilitate hepatic fibrosis. The findings reveal a new mechanism and a potential therapeutic target for arsenite-induced hepatic fibrosis.

Determining of arsenic (As) exposure was conducted in 110 residents which divided into two groups using the WHO guidelines for As in drinking water of 10 μg/L. Moreover, questionnaires with face-to-face interviews were used to make a health risk assessment and to determine the associated factors. The median of As in urine was 61.33 μg/L (5.38-600.86 μg/L), accounting for 68.18% of participants who exposed to the contaminated groundwater had obviously high urinary As levels, exceeded the normal value of 50 μg/L of As, as set by the National Health and Nutrition Examination Survey (NHANES). The major factor affecting As in urine was the As contaminated groundwater. Pearson's chi-squared test showed that the urinary As level was influenced on the different groups of As level in groundwater (p-value <0.001). Multiple linear regression confirmed that the actual risk factors of As in urine were the As level in groundwater and the oral exposure route but not the dermal contact. Meanwhile binary logistic regression revealed that all socio-demographic factors were not influenced. Approximately 45.45% of the area had the HI above the risk level of 1, mostly via groundwater drinking pathway. The estimated total cancer risk values, 5.11 × 10^-6 to 2.08 × 10^-3, were higher than the safe level of 10^-6. For long-term exposure, the As concentration and exposure duration were the most variables influencing health risk level. This finding suggests that chronic As exposure should be monitored and also the groundwater should be improved to provide the safe drinking water for the residents.

Nearly half of the world's urban population depends on aquifers for drinking water. These are increasingly vulnerable to pollution and overexploitation. Besides anthropogenic sources, pollutants such as arsenic (As) are also geogenic and their concentrations have, in some cases, been increased by groundwater pumping. Almost 40 % of Mexico's population relies on groundwater for drinking water purposes; much the aquifers in semi-arid and arid central and northern Mexico is contaminated by As. These are agricultural regions where irrigation water is primarily provided from intenstive pumping of the aquifers leading to long-standing declines in the water table. The focus of this study is the main aquifer within the Comarca Lagunera region in Northern Mexico. Although the scientific evidence demonstrates that health effects are associated with long-term exposure to elevated As concentrations, this knowledge has not yielded effective groundwater development and public health policy. A multidisciplinary approach - including the evaluation of geochemistry, human health risk and development and public health policy - was used to provide a current account of these links. The dissolved As concentrations measured exceeded the corresponding World Health Organization guideline for drinking water in 90 % of the sampled wells; for the population drinking this water, the estimated probability of presenting non-carcinogenic health effects was >90 %, and the lifetime risk of developing cancer ranged from 0.5 to 61 cases in 10,000 children and 0.2 to 33 cases in 10,000 adults. The results suggest that insufficient policy responses are due to a complex and dysfunctional groundwater governance framework that compromises the economic, social and environmental sustainability of this region. These findings may valuable to other regions with similar settings that need to design and enact better informed, science-based policies that recognize the value of a more sustainable use of groundwater resources and a healthier population.

To investigate the leaching characteristics and potential environmental effects of potentially toxic metals (PTMs) from alum mine tailings in Lujiang, Anhui Province, soaking tests and simulated rainfall leaching experiments were conducted for two types of slag. PTMs comprising Cd, Cr, Cu, Mn, and Ni were detected in the slag. Cu and Cd contents exceeded the national soil risk screening values (GB 15618-2018). pH values of the two slag soaking solutions were negatively correlated with the solid:liquid ratio. pH values of the sintered slag soaking solutions with different solid:liquid ratios finally stabilized between 4.4 and 4.59, and those of the waste slag soaking solutions finally stabilized between 2.7 and 3.4. The concentrations of Cd, Cr, Cu, Mn, and Ni leached from waste slag were higher than those from sintered slag, and the dissolved concentrations of these PTMs in sintered slag were higher under rainfall leaching conditions than soaking conditions (the difference in Cr concentration was the smallest, 5.6%). The cumulative release of Cd, Cr, Cu, Mn, and Ni increased as the leaching liquid volume increased. The kinetic characteristics of the cumulative release of the five PTMs were best fitted by a double constant equation (R² > 0.98 for all fits). Single factor index evaluations showed that Mn and Ni were the PTMs with high pollution degrees (P_i for Mn and Ni exceed 1) in the leaching solutions. However, considering the biotoxicity of PTMs, the water quality index evaluations showed that the water quality of the sintered slag soaking solution, the waste slag soaking solution, and the sintered slag leachate was good, poor, and undrinkable, respectively. The health risk assessment showed that the total non-carcinogenic risk (HI) values in adults for both the sintered slag leachate and waste slag soaking solution exceeded the safe level of 1, with HI values of 3.965 and 2.342, respectively. The hazard quotient (HQ) for Cd was 1.994 for the sintered slag leachate, and Cd and Cr make up 50.29% and 15.93% of the total risk, respectively. Cr makes up 28.38% of the total risk for the waste slag soaking solution. These results indicate a high non-carcinogenic risk of exposure to Cd and Cr in the leaching solution used for drinking purposes. These findings may provide a reference for the evaluation and ecological control of PTM pollution in alum mining areas.

Microbes have important impacts on the mobilization of arsenic in groundwater. To study the effects of sulfide on As(V) bioreduction in sulfidic groundwater, Citrobacter sp. JH012-1 isolated from sediments in the Jianghan Plain was used in a microcosm experiment. The results showed that sulfide significantly enhanced As(V) bioreduction as an additional electron donor. The reduction rates of As(V) were 21.8%, 34.5%, 73.6% and 85.9% under 0, 15, 75 and 150 µM sulfide inputting, respectively. The main products of As(V) bioreduction were thioarsenite and orpiment and the concentration of thioarsenite reached to 5.5 and 7.1 µM in the solution with the initial 75 and 150 µM sulfide, respectively. However, under 0 and 15 µM sulfide inputting, the dominant product was arsenite with no thioarsenite accumulation. The decrease in pH enhanced the bioreduction of As(V) and promoted the formation of thioarsenite and orpiment. In addition, the percentage of thioarsenite in total arsenic decreased with the decrease in the ratio of sulfur to arsenic, indicating that the formation of thioarsenite was limited by the concentration of initial sulfide. Therefore, the presence of sulfide had a significant effect on the transformation of arsenic in groundwater. This study provides new insights into the bioreduction of As(V) and the formation of thioarsenite in sulfidic groundwater.

In this research, diatoms as the first step and fishes as the last step of the food chain were compared as toxic metal accumulation bioindicator in an A-class wetland in Turkey. Bioaccumulations of potentially toxic elements (PTEs) were determined in liver, gill and muscle tissues of two commercially consumed fish species Carassius gibelio and Cyprinus carpio and in frustules of epiphytic diatom communities living on submerged macrophytes. Samples were collected seasonally from the Gala Lake, which is among the best stopover habitats of birds migrating between Europe and Africa, considering the paddy harvest period that is a major stress factor for the ecosystem. Also, potential human health risks associated with the consumption of fishes and consumption - dermal contact of diatoms were evaluated both for summer - before paddy harvest (BPH) and autumn - after paddy harvest (APH) periods. As a result of this research, the investigated toxic metal concentrations were increased significantly in diatoms in the APH period, while less significant exchanges were recorded in fishes. The bioaccumulations of PTEs were ranked as follows: Zn > Mn > Se > Cu > B > Cr > Ni > As > Pb > Cd for C. gibelio; Zn > Mn > Se > Cu > B > Cr > As > Ni > Pb > Cd for C. carpio; and Mn > Zn > Se > Pb > B > Ni > Cr > Cu > As > Cd for diatom frustules. Although the HI values in diatoms detected in the APH period were statistically significantly higher (about 1000 times; p < 0.05) than detected in the BPH period, they were less than the limit of 1 in both seasons. However, the HI coefficients of fishes were quite higher than the limit (an average of 23.59 for C. gibelio and 19.18 for C. carpio), which means quite high probable non-carcinogenic health risks for humans. Furthermore, the CR coefficients of Cr, Ni and As in muscle tissues of fishes were considerably higher than the limit of 10-4, which reflects a significant carcinogenic health risk for consumers. The data showed that although the fishes at the top of the food chain bioaccumulate the PTEs in their tissues much higher than the diatoms at the bottom of the food chain, the diatoms are much more sensitive to changes in the environmental conditions than the fishes and they are more effective biological tools as toxic metal accumulation bioindicators.

Groundwater, is an alternative resource, is used as a supplement for irrigation as well as drinking purposes in Pakistan. This paper aims to determine the quantum and quality of groundwater in Matiari district of Sindh, Pakistan, through Electrical Resistivity Survey (ERS). The ERS was conducted at 52 location points using the ABEM Terrameter SAS 4000. The quantity of good quality groundwater has also been evaluated with ArcGIS interpolation techniques, i.e., the maximum percentage of fresh groundwater is 34% the marginal fresh groundwater 43% at the depth of with few patches of saline groundwater aquifers. Moreover, at 50-m depth, the percentage of fresh groundwater reduces to 21% and the marginal has increased to 48%. However, groundwater below the depth from 50 to 100 m was found only 8% fresh groundwater, 29% marginal, 49% salt water, and 14% high salt water. Analysis of groundwater samples for quality showed a good agreement with the quality obtained from VES results. In addition, a socio-economic survey of 55 tube well owners were conducted through interviews related to groundwater suitability and usage. According to the survey, about 62% of respondents are using good quality groundwater; however, 36% consuming the marginal and the remaining 2% are utilizing the hazardous quality of groundwater. The consumer satisfaction survey showed most farmers (89%) were satisfied with the groundwater usage, while 11% were unsatisfied due to poor-quality groundwater. The crop productivity could be enhanced through awareness and conjunctive use of marginal quality groundwater with the canal water.

Exposure to high level of arsenic (As) through the ingestion of contaminated soil, dust and food plants can pose health risk to humans. This study investigates the total arsenic (As), arsenobetaine (AsB), monomethylarsenate (MMA), dimethylarsenate (DMA), arsenite (As³⁺) and arsenate (As⁵⁺) concentrations in poultry feed, manure, agricultural soils and food plants collected from Khyber Pakhtunkhwa Province, Pakistan. The total mean As concentrations in the edible parts of food plants ranged from 0.096 mg kg^-1 to 1.25 mg kg^-1 with percentile (P) values (P25-0.039, P50-0.0765, P75-0.165 1 mg kg^-1 to P25-0.95, P50-1.23, P75-1.6 1 mg kg^-1) and exceeded the food safety limit (0.1 mg kg^-1) of Food & Agriculture Organization (FAO) and World Health Organization (WHO) in all plant species except Pisum sativum (pea) and Mentha arvensis (mint). The risk to human health was assessed through the average daily intake (ADI), hazards quotient (HQ), health risk index (HRI) and lifetime cancer risk (LTCR). The highest average daily intake of As via the ingestion of Malva neglecta (mallow, a leafy plant) was observed for adults and children. The ADI for adults and children (2.36 × 10^-4 mg kg^-1 day^-1 and 6.33 × 10^-4 mg kg^-1 day^-1) was about 13% and 5%, respectively, of the Bench Mark Dose Limit (BMDL_0.5) of 3.00 × 10^-3 mg kg^-1 day^-1 set by WHO. The HRI was 3 times more in the children (2.1) than the adults (0.79), posing non-cancer health risks (health risk index > 1) for children. The LTCR values were slightly higher (1.53 × 10^-4) relative to USEPA and WHO limits (1 × 10^-6 to 1 × 10^-4) for children whereas a minimal cancer risk was observed for adults via consumption of selected food plants. The results showed that poultry manure can contaminate food plants that may lead to cancer and non-cancer risks in agricultural areas, Pakistan. Thus, it is important to minimize As concentration in poultry feed to safeguard human health and environment from adverse effects.

There is no human data regarding the exposure, metabolism and potential health effects of arsenic (As) contamination in drinking water in the Central Anatolian region of Turkey.

Residents in ten villages with drinking water of total As (T-As) level >50 μg L^-1 and 10-50 μg L^-1 were selected as an exposed group (n = 420) and <10 μg L^-1 as an unexposed group (n = 185). Time-weighted average-As (TWA-As) intake was calculated from T-As analysis of drinking water samples. Concentrations of T-As in urine and hair samples, urinary As species [i.e., As(III), As(V), MMA(V) and DMA(V], and some micronutrients in serum samples of residents of the study area were determined. Primary and secondary methylation indices (PMI and SMI, respectively) were assessed from urinary As species concentrations and the presence of skin lesion was examined.

TWA-As intake was found as 75 μg L^-1 in the exposed group. Urinary and hair T-As and urinary As species concentrations were significantly higher in the exposed group (P < 0.05). The PMI and SMI values revealed that methylation capacities of the residents were efficient and that there was no saturation in As metabolism. No significant increase was observed in the frequency of skin lesions (hyperpigmentation, hypopigmentation, keratosis) of the exposed group (P > 0.05). Only frequency of keratosis either at the hand or foot was higher in individuals with hair As concentration >1 μg g^-1 (P < 0.05).

Individuals living in the study area were chronically exposed to low-to-moderate As due to geological contamination in drinking water. No significant increase was observed in the frequency of skin lesions. Because of the controversy surrounding the health risks of low-to-moderate As exposure, it is critical to initiate long-term follow-up studies on health effects in this region.