Concentrations In Drinking Water Research Articles

Novel evidence of arsenic-related excess adiposity and its implication in the risk of cardiometabolic diseases.

Arsenic exposure is associated with obesity- or excess adiposity-related disorders, including cardiometabolic diseases. Previously, many human studies attempted to establish the association of arsenic exposure with obesity, mainly through body mass index (BMI) but failed to provide any concrete evidence. Our study aimed to investigate the arsenic-related adiposity and its relationship with cardiometabolic diseases. Of the 524 participants, 126 and 398, respectively, were chosen from low- and high-arsenic exposure areas in Bangladesh. Obesity or body fat (adiposity) of the participants was measured by anthropometric measures [BMI, waist circumference (WC), and triceps skinfold thickness (TSFT)] and a serum biomarker, leptin. Sarcopenic characteristics were assessed by lean body mass (LBM) and serum creatinine levels. Insulin resistance, as measured by Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), hypertension, and hyperglycemia, were considered as the risk factors for cardiometabolic diseases. There were significant positive associations between drinking water, hair, and nail arsenic concentrations and the levels of WC and TSFT after adjusting for potential confounders. However, there were no significant associations with BMI. Increased arsenic exposure levels were associated with increased leptin levels [(Regression coefficient (β)=1.00, 95% confidence interval (CI): 0.53, 1.46) for water, (β=1.44, 95% CI: 0.42, 2.46) for hair, and (β=1.47, 95% CI: 0.32, 2.61) for nail arsenic]. Notably, leptin levels had inverse associations with LBM (β=-7.87, 95% CI: -13.30, -2.45) and creatinine levels (β=-15.65, 95% CI: -21.50, -9.81). Furthermore, the elevated leptin levels associated with arsenic exposure were connected to higher HOMA-IR levels (β=0.19, 95% CI: 0.14, 0.24), higher odds of hypertension [Odds ratio (OR)=1.31, 95% CI: 1.12, 1.53], and hyperglycemia (OR=1.30, 95% CI: 1.13, 1.47). Taken together, the results of this study demonstrated a unique association between arsenic exposure and adiposity, which could promote arsenic-induced cardiometabolic disorders by mirroring the distinctive characteristics of age-associated sarcopenic obesity.

Spatial and temporal distribution of arsenic concentration in rural drinking water and health risk assessment in Northern China from 2013 to 2022: a case study of Inner Mongolia Autonomous Region

BackgroundBy monitoring arsenic levels in rural drinking water in Inner Mongolia Autonomous Region from 2013 to 2022 and evaluating their health risks, this study provides a basis for further developing strategies to promote public health.MethodsOne stable centralized water supply point was randomly selected in each township of Inner Mongolia Autonomous Region. One finished water sample and 1–3 tap water samples were collected at each supply point. Water samples were collected once during the dry season (May) and once during the rainy season (August-September). Mann-Whitney U test was used to compare arsenic concentrations in drinking water from different types of water sources, and Kruskal-Wallis test was used to compare arsenic concentrations in drinking water across different years. Environmental health risk assessment was conducted using the health risk assessment model recommended by the US Environmental Protection Agency (USEPA).ResultsOverall, arsenic concentrations in rural drinking water were higher in the central-western part of Inner Mongolia Autonomous Region compared to the eastern part. From 2013 to 2022, there was a notable decreasing trend in arsenic concentrations in rural drinking water, with over 98% of water samples meeting arsenic standards by 2022. During 2013–2019, arsenic concentrations in drinking water sourced from groundwater were consistently higher than those from surface water sources (P < 0.05). Hazard quotient (HQ) values for the entire population were below 1, and lifetime cancer risk (LCR) values exceeded 1 × 10− 6. Sensitivity analysis indicated that drinking water arsenic concentration contributed the most to health risks for the population.ConclusionDuring 2013–2022, through concerted efforts by the government and the people, excessive arsenic levels in rural drinking water have been significantly reduced, resulting in decreased health risks for the population. However, some carcinogenic risks still exist.Therefore, the next critical step in improving water quality in the region involves further optimizing methods such as coagulation, adsorption, or ion exchange to remove arsenic from drinking water.

Assessment of Radon Concentration and Health Hazards in Natural Spring Water of a Sub-Himalayan District

The objective of this study was to evaluate the extent of radon contamination in twenty-six drinking water samples from natural springs were collected from Dhirkot Azad Kashmir, along with four bottled mineral water samples. Radon gas escapes from the earth’s crust due to uranium ores and diffuses into the atmosphere. This study assessed the levels of radon concentration, the yearly effective radiation dose, and carcinogenic risk from radon exposure in drinking water samples. The radon concentration varied from 0.28 to 30.25 Bq/L. The mean radon concentration of all samples was found to be 7.86 ± 2.3 Bq/L. The radon concentrations in bottled drinking water were found to be lower than those in natural springs. The statistical and GIS analyses included the use of interpolation and Pearson’s correlation matrix. Seven samples had radon concentration that surpassed the standard limit established by the US-EPA, which is 11 Bq/L. The average annual effective dose from inhalation and ingestion was found to be lower than the value (0.1 mSv/y) provided by the WHO, but for some natural spring water samples, it exceeded the risk limit. The cancer risk revealed that 40% of the samples had an elevated lifetime cancer risk from radon exposure. Overall, the majority of the results obtained aligned with the worldwide guidelines established by the US-EPA. However, there were a few instances where the limits were exceeded, and constant monitoring is recommended. This study establishes a baseline for radon concentration in the area and provides a basis for future studies.

NTP monograph on the state of the science concerning fluoride exposure and neurodevelopment and cognition: a systematic review.

Fluoride is a common exposure in our environment that comes from a variety of sources and is widely promoted for its dental and overall oral health benefits. Contributions to an individual's total exposure come primarily from fluoride in drinking water, food, beverages and dental products. A 2006 evaluation by the National Research Council (NRC) found support for an association between consumption of high levels of naturally occurring fluoride in drinking water and adverse neurological effects in humans and recommended further investigation. The evidence reviewed at that time was from dental and skeletal fluorosis-endemic regions of China. Since the NRC evaluation, the number and location of studies examining cognitive and neurobehavioral effects of fluoride in humans have grown considerably, including several recent North American prospective cohort studies evaluating prenatal fluoride exposure. In 2016, the National Toxicology Program (NTP) published a systematic review of the evidence from experimental animal studies on the effects of fluoride on learning and memory. That systematic review found a low-to-moderate level of evidence that deficits in learning and memory occur in non-human mammals exposed to fluoride. To conduct a systematic review of the human, experimental animal, and mechanistic literature to evaluate the extent and quality of the evidence linking fluoride exposure to neurodevelopmental and cognitive effects in humans. A systematic review protocol was developed and utilized following the standardized OHAT systematic review approach for conducting literature-based health assessments. This monograph presents the current state of evidence associating fluoride exposure with cognitive or neurodevelopmental health effects and incorporated predefined assessments of study quality and confidence levels. Benefits of fluoride with respect to oral health are not addressed in this monograph. The bodies of experimental animal studies and human mechanistic evidence do not provide clarity on the association between fluoride exposure and cognitive or neurodevelopmental human health effects. Human mechanistic studies were too heterogenous and limited in number to make any determination on biological plausibility. This systematic review identified studies that assessed the association between estimated fluoride exposure and cognitive or neurodevelopmental effects in both adults and children, which were evaluated separately. The most common exposure assessment measures were drinking water concentrations and estimates of total fluoride exposure, as reflected in biomarkers such as urinary fluoride. In adults, only two high-quality cross-sectional studies examining cognitive effects were available. The literature in children was more extensive and was separated into studies assessing intelligence quotient (IQ) and studies assessing other cognitive or neurodevelopmental outcomes. Eight of nine high-quality studies examining other cognitive or neurodevelopmental outcomes reported associations with estimated fluoride exposure. Seventy-two studies assessed the association between fluoride exposure and IQ in children. Nineteen of those studies were considered to be high quality; of these, 18 reported an inverse association between estimated fluoride exposure and IQ in children. The 18 studies, which include 3 prospective cohort studies and 15 cross-sectional studies, were conducted in 5 different countries. Forty-six of the 53 low-quality studies in children also found evidence of an inverse association between estimated fluoride exposure and IQ in children. Existing animal studies provide little insight into the question of whether fluoride exposure affects IQ. In addition, studies that evaluated fluoride exposure and mechanistic data in humans were too heterogenous and limited in number to make any determination on biological plausibility. The body of evidence from studies in adults is also limited and provides low confidence that fluoride exposure is associated with adverse effects on adult cognition. There is, however, a large body of evidence on associations between fluoride exposure and IQ in children. There is also some evidence that fluoride exposure is associated with other neurodevelopmental and cognitive effects in children; although, because of the heterogeneity of the outcomes, there is low confidence in the literature for these other effects. This review finds, with moderate confidence, that higher estimated fluoride exposures (e.g., as in approximations of exposure such as drinking water fluoride concentrations that exceed the World Health Organization Guidelines for Drinking-water Quality of 1.5 mg/L of fluoride) are consistently associated with lower IQ in children. More studies are needed to fully understand the potential for lower fluoride exposure to affect children's IQ.

Low levels of per- and polyfluoroalkyl substances (PFAS) detected in drinking water in Norway, but elevated concentrations found near known sources

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous contaminants which are also found in drinking water. Concentration levels in drinking water vary widely and range from a very low contribution to total daily exposure for humans to being the major source of uptake of PFAS. PFAS concentrations in Norwegian drinking water has been rarely reported. We investigated concentrations of 31 PFAS in 164 water samples, representing both source water (i.e., before drinking water treatment) and finished drinking water. Samples were taken from 18 different water bodies across Norway. The 17 waterworks involved supply drinking water to 41 % of the Norwegian population. Only four of the waterworks utilised treatment involving activated carbon which was able to significantly reduce PFAS from the source water. Samples of source water from waterworks not employing activated carbon in treatment were therefore considered to represent drinking water with regards to PFAS (142 samples). All samples from one of the water bodies exceeded the environmental quality standard (EQS) for perfluorooctane sulfonic acid (PFOS) according to the water framework directive (0.65 ng/L). No concentrations exceeded the sum of (20) PFAS (100 ng/L) specified in the EU directive 2020/2184 for drinking water. Several EU countries have issued lower guidelines for the sum of the four PFAS that the European Food Safety Authority (EFSA) has established as the tolerable weekly intake (TWI) for PFOS, perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexane sulfonic acid (PFHxS). Denmark and Sweden have guidelines specifying 2 and 4 ng/L for the sum of these PFAS. Only one of the 142 drinking water samples exceeded the Danish TWI and contained a sum of 6.6 ng/L PFAS. A population exposure model, for individuals drinking water from the investigated sources, showed that only 0.5 % of the population was receiving PFAS concentrations above the Danish limit of 2 ng/L.

Risk assessment for perfluorooctanoic acid (PFOA) in air, blood serum and water: mortality from liver and kidney disease

BackgroundCancer and non-cancer associations have been observed with PFAS (perfluoroalkyl and polyfluoroalkyl) substances in the general population, in populations from locally contaminated environments and in exposed workers.MethodsA quantitative risk assessment...

Environmental fate of monosodium methanearsonate (MSMA)-Part 2: Modeling sequestration and transformation.

Monosodium methanearsonate(MSMA), a sodium salt of monomethylarsonic acid (MMA),is a selective contact herbicide used for the control of a broad spectrum of weeds. In water, MSMA dissociates to ions of sodium (Na+) and monomethylarsonate (MMA-)thatis stable and does not transform abiotically. In soils characteristic of MSMA use, several simultaneous processes can occur: (1) microbial methylation of MMA to dimethylarsinic acid (DMA), (2) microbial demethylation of MMA to inorganic arsenic (iAs), (3) methylation of iAs to MMA, and (4) sorption and sequestration of MMA and its metabolites to soil minerals. Sequestered residues are residues that cannot be desorbed from soil in environmental conditions. Sequestration is rapid in the initial several days after MSMA application and continues at a progressively slower rate over time. Once sequestered, MMA and its metabolites are inaccessible to soil microorganisms and cannot be transformed. The rate and extent of the sorption and sequestration as well as the mobility of MMA and its metabolites depend on the local edaphic conditions. In typical MSMA use areas, the variability of the edaphic conditions is constrained. The goal of this research was to estimate the amount of iAs potentially added to drinking water as a result of the use of MSMA, with models and scenarios developed by the US Environmental Protection Agency for pesticide risk assessment. In this project, the estimated drinking water concentrations (EDWCs) for iAs were assessed as the average concentration in the reservoir over a 30-year simulation with annual applications of MSMA at maximum label rates. When the total area of suitable land was assumed to be treated, EDWCs ranged from <0.001 to 0.12 µg/L. When high estimates of actually treated acreage are considered, the EDWCs are below 0.06 µg/L across all scenarios. Integr Environ Assess Manag 2024;20:2076-2087. © 2024 The Author(s). Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Simultaneous removal of fluoride and arsenic from drinking groundwater using limestones from Bajío Guanajuatense, Mexico

Numerous groundwater wells in Mexico exceed the maximum allowable fluoride (F−) and arsenic (As) drinking water concentration requirements, posing an environmental and health risk to the population that relies solely on these wells for drinking water sources. Since encouraging results have been obtained utilizing native limestones to remove some toxic elements from contaminated water, the ability of the limestone rock outcrop to the south of the Sierra de Guanajuato in Mexico to remove As and F− from groundwater was assessed. A sampling campaign was conducted in the study area, focusing on wells exhibiting elevated concentrations of arsenic (As) and fluoride (F−) in compliance with international standards. This water was employed in the treatment experiment involving limestone rocks. The rock sampling process involved a reconnaissance campaign covering the study area and outcrop points of limestone rocks. Representative limestone samples were collected and subsequently subjected to mineralogical and geochemical characterization. Using rock samples, synthetic water, and groundwater from contaminated wells in the region, batch experiments were conducted to evaluate the As and F− removal capacity of limestone. The batch testing consisted of water–rock interactions at various times with different samples of limestone rocks, grain sizes, and water containing distinct concentrations of both elements, artificial and groundwater extracted close to the limestones outcrop. The results indicate that the rock with the highest calcium carbonate (CaCO3) content and the smallest grain size (< 0.05 mm) removes the highest concentrations of both As and F−, with As removal being superior. The removal mechanisms were studied using scanning electron microscopy with energy-dispersive spectroscopy (SEM–EDS) images, saturation index calculations, and Eh–pH diagrams,. Fluoride precipitation was favored when the pH of the solution was slightly acidic, whereas sorption was favored when the pH was higher. The results obtained are encouraging for the removal of high levels of As, and to a lesser extent for F−; consequently, the use of regional limestone rocks could be a viable option for improving the water quality ingested by rural inhabitants in the study area. Calcium carbonate (CaCO3) concentration can be used to identify limestone rocks with the potential to effectively remove As and F− in other locations.

Determination of radon concentration in bottled drinking water of Dhaka City

ABSTRACT Among all natural radiation sources, exposure to radon (222Rn) is considered as the most hazardous to human health. Recognizing the significance of water in preserving a healthy life style, assessing the 222Rn activity in drinking water is crucial. The 222Rn activity concentration was measured in 20 different branded bottled drinking waters purchased from Dhaka city using both alpha and gamma-ray spectrometry systems. Activity concentrations of 222Rn in bottled water obtained via RAD7 detector varied from 0.1 ± 0.02 Bq/L to 0.42 ± 0.01 Bq/L with an average value of 0.26 ± 0.02, while the value varied from 0.12 ± 0.01 Bq/L to 0.52 ± 0.31 Bq/L with an average value of 0.29 ± 0.09 by HPGe detector. The obtained results show lower concentrations when compared with other studies around the world as well as the US-EPA reference level of 11.1 Bq l−1 or 300 pCi l−1. The total annual effective dose calculated for different age groups and internal organ doses were found below the action level recommended by WHO (0.1 mSv y−1) and ICRP (3–10 mSv y−1), due to 222Rn, 3H and 40K in drinking water. Based on the obtained radon concentration and concomitant dose values, this study suggested negligible health hazards due to the consumption of bottled drinking water in Bangladesh. The results of this study could serve as a reference data for future studies in the area and beyond.

Efficient detection of Sn2+ by 4-aminobenzenesulfonamide based Schiff base chemosensor

A novel Schiff base colorimetric and fluorometric chemosensor N-((E)-2-hydroxy-3-methoxybenzylidene)-4-(((Z)-2-hydroxy-3-methoxybenzylidene)amino)benzenesulfonamide (SOV), has been designed, synthesized and characterized by using spectroscopic techniques. The chemosensor SOV showed selective and sensitive colorimetric sensing ability for Sn2+ metal ion in THF: H2O (9:1, v/v) solvent mixture exhibited colorless to light yellow changes. When Sn2+ ion was added, it showed a considerable fluorescence enhancement, because photoinduced electron transfer (PET) has been blocked. More importantly that spectroscopic studies showed SOV to be a fast-responding, low detection limit (3.034 × 10−9M), which are much lower than the WHO-approved drinking water concentration and a good binding constant (2.81 × 103M−1). Furthermore, it was discovered that the EDTA in chemosensor SOV made it to function as a reversible fluorescence probe towards the Sn2+ ions. A metal coordination, PET, as well as an internal charge transfer (ICT) process might be interpreted as the detecting mechanism based on physicochemical and analytical techniques such as 1H NMR spectra, FT-IR, Elemental analysis, ESI-mass spectrometry, Job’s plot, and DFT studies. Fluorescence imaging experiments of Sn2+ in living MCF 7 cells demonstrated its value of practical applications in biological systems.

Prediction of human health risk and disability-adjusted life years induced by heavy metals exposure through drinking water in Fars Province, Iran

Exposure to heavy metals in contaminated drinking water is strongly correlated with various cancers, highlighting the burden of disease. This study aimed to assess the non-carcinogenic and carcinogenic risks associated with exposure to heavy metals (As, Pb, Cd, and Cr) in drinking water of Fars province and evaluate the attributed burden of disease. Non-carcinogenic risk assessment was performed using the hazard quotient (HQ) method, while the carcinogenic risk assessment utilized the excess lifetime cancer risk approach. The burden of disease was evaluated in terms of years of life lost, years lived with disability, and disability-adjusted life years (DALY) for three specific cancers: skin, lung, and kidney cancer. The average drinking water concentrations of arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb) were determined to be 0.72, 0.4, 1.10 and 0.72 μg/L, respectively. The total average HQ of heavy metals in drinking water in the study area were 0.127, 0.0047, 0.0009 and 0.0069, respectively. The average ILCRs of heavy metal in the entire country were in the following order: 1.15 × 10−5 for As, 2.22 × 10−7 for Cd and 3.41 × 10−7 for Cr. The results also indicated that among the various counties analyzed, Fasa experiences the greatest burden of disease in terms of DALYs, with a value of 87.56, specifically attributed to cancers caused by exposure to arsenic. Generally, it can be said that the burden of disease is a critical aspect of public health that requires comprehensive understanding and effective intervention.

Prenatal exposure to nitrosatable drugs and timing of puberty in sons and daughters: A nationwide cohort study.

N-nitroso compounds (NOCs) can be formed by endogenous reactions between nitrosatable drugs and nitrite. Animal studies have found that several NOCs are teratogenic, and epidemiological studies report associations between prenatal exposure to nitrosatable drugs and adverse birth outcomes. It is unknown whether prenatal exposure to nitrosatable drugs is harmful to the child's reproductive health, including pubertal development. We investigated whether prenatal exposure to nitrosatable drugs was associated with timing of puberty and whether nitrate, nitrite and antioxidant intake modified any association. The population-based Danish National Birth Cohort (DNBC) Puberty Cohort, which includes 15,819 children, was used to investigate the association between prenatal exposure to nitrosatable drugs and timing of puberty. Around gestational week 11 and gestational week 18, mothers provided information about drug use during pregnancy. The children's self-reported information on onset of pubertal milestones was collected every six months from 11 years of age and throughout puberty. To investigate potential effect modification by nitrite, nitrate and antioxidant intake, information on these factors was obtained from a food frequency questionnaire completed by the mothers in gestational week 25, and information on nitrate concentration in maternal drinking water at her residential address was obtained from monitoring data from public waterworks. Data were analysed using a multivariable regression model for interval-censored data estimating difference in months in timing of puberty between exposure groups. A total of 2,715 children were prenatally exposed to nitrosatable drugs. We did not find an association between prenatal exposure to nitrosatable drugs and timing of puberty. This finding was supported by null-findings in the following sub-analyses investigating: 1. subtypes of nitrosatable drugs (secondary and tertiary amines and amides), 2. dose-dependency (duration of drug intake), 3. effect modification by maternal intake of nitrate, nitrite, and antioxidants. 4. confounding by indication. Prenatal exposure to nitrosatable drugs was not associated with timing of puberty. Nitrosatable drugs are commonly used drugs in pregnancy, and further research is needed to allow firm conclusions on the potential effect of prenatal exposure to nitrosatable drugs on the child's reproductive health.

Removal of disinfection byproducts through integrated adsorption and reductive degradation in a membrane-less electrochemical system

Proper control/removal of disinfection byproducts (DBPs) is important to drinking water safety and human health. In this study, a membrane-less electrochemical system was developed and investigated to remove DPBs through integrated adsorption and reduction by granular activated carbon (GAC)-based cathode. Representative DPBs including trihalomethanes and haloacetonitriles at drinking water concentrations were used for removal experiments. The proposed system achieved >70% removal of most DBPs in a batch mode. The comparison with control tests under either open circuit or hydrolysis demonstrated the advantages of electrochemical treatment, which not only realized higher DPBs removal but also extended GAC cathode lifetime. Such advantages were further demonstrated with continuous treatment. High dechlorination and debromination efficiencies were obtained in both batch (82.2 and 94.3%) and continuous (79.3 and 87.6%) reactors. DBPs removal was mainly contributed by the electrochemical reduction and adsorption by the GAC-based cathode, while anode showed little oxidizing effect on DBPs and halide ions. Dehalogenated products of chloroform and dichloroacetonitrile were identified with toxicity reduction. The energy consumption of the continuously operated system was estimated to be 0.28 to 0.16 kWh m−3. The proposed system has potential applications for wastewater reuse or further purification of drinking water.

Tritium concentration in bottled drinking water and internal dose assessment

Tritium concentration in bottled drinking water and internal dose assessment

Nanoprecipitated CoPi enhanced photoelectrochemical water oxidation toward sensitive and selective Co2+ detection

The detection of heavy metal ions Co2+ is of great significance to the environment and human health. Herein, a simple, highly selective and sensitive photoelectrochemical detection strategy for Co2+ was developed based on the enhanced activity by nanoprecipitated CoPi on the Au nanoparticle decorated BiVO4 electrode. The new photoelectrochemical sensor has a low detection limit of 0.03 μΜ and wide detection range of 0.1–10, and 10–6000 μΜ, with a high selectivity over other metal ions. The Co2+ concentration in tap water and commercial drinking water has also been successfully determined with the proposed method. Scanning electrochemical microscopy technique was employed to characterize the photocatalytic performance and heterogenous electron transfer rate of electrodes in situ, further revealing the photoelectrochemical sensing mechanism. Besides determining Co2+ concentration, this approach of enhanced catalytic activity by nanoprecipitation can be further extended to develop a variety of electrochemical, photoelectrochemical and optical sensing platforms for many other hazardous ions and biological molecules.

A comparative study of underground water arsenic contamination and suffering of people in Flood Plain with Deltaic reason of Bangladesh

The people were drinking arsenic-contaminated underground water in Bangladesh. We had analyzed 33,092 hand tube-well water samples, collected from all four geomorphological areas (i.e., from all 64 districts) in Bangladesh and found arsenic in 60 districts that were above the WHO recommended value in drinking water (10 μg/L) and in 50 districts that were above maximum permissible limit, 50 μg/L. In this paper, I have reported the magnitude of arsenic contamination in the tubewell water samples that were collected from two districts of Bangladesh, one from Flood Plain, named Chandpur, and another one from Deltaic region, named Madaripur. It describes the analytical report of arsenic concentrations in underground drinking water and biological samples, and people suffering from arsenic toxicity in these two districts. In the Madaripur district, 19.62% of the total tubewell water samples (n=2,309) contained arsenic concentrations that were below WHO recommended value (10 μg/L) and safe to drink, and 80.38% and 59.59% of the tubewells contained levels arsenic that were above 10 μg/L and 50 μg/L, respectively. In Chandpur district (n=1,165 tubewell water samples), these values are 4.12, 95.88, and 92.79%, respectively. Of the samples in Madaripur, the percentage of water samples with arsenic are 26.94, 12.68, 3.29. 0.91, and 0.22% in the ranges 100-299, 300-499, 500-699, 700-1,000, and above 1,000 μg As/L, respectively. In Chandpur district, these values are 57.86, 25.15, 4.81, 1.80, and 0.43%, respectively.

Azithromycin induces read-through of the nonsense Apc allele and prevents intestinal tumorigenesis in C3B6F1 ApcMin/+ mice

Therapeutic strategies that promote read-through of a mutant gene have proved effective for certain non-neoplastic diseases. However, the efficacy of this approach is unproven regarding neoplastic diseases with germline nonsense mutations, including familial adenomatous polyposis. Here we examined the cancer-preventive efficacy of the macrolide antibiotic azithromycin, with a reported read-through effect, on intestinal tumorigenesis in C3B6F1 ApcMin/+ mice harboring a nonsense Apc mutation resulting in a truncated Apc protein. Mice were given drinking water lacking azithromycin or containing 0.0125–0.2 mg/mL azithromycin from 3 weeks of age. The small intestine and cecum were analyzed for pathological changes and alterations of intestinal flora. Azithromycin suppressed the number of tumors and the proportion of adenocarcinomas, with the most effective drinking-water concentration being 0.0125 mg/mL. Furthermore, azithromycin recovered the cellular level of full-length Apc, resulting in downregulation of β-catenin and cyclin D1. Conversely, the effect of azithromycin on the diversity of the intestinal microbiota depended on the drinking-water concentration. These results suggest that the balance between azithromycin-mediate read-through of mutant Apc mRNA and antibacterial effects influences intestinal tumorigenesis. Thus, azithromycin is a potential anticancer agent for familial adenomatous polyposis patients harboring nonsense mutations.

Estimation of Serum PFOA Concentrations from Drinking and Non-Drinking Water Exposures.

Estimation of Serum PFOA Concentrations from Drinking and Non-Drinking Water Exposures.

Spatio-temporal trends in livestock exposure to per- and polyfluoroalkyl substances (PFAS) inform risk assessment and management measures

The migration of per- and polyfluoroalkyl substances (PFAS) onto agricultural properties has resulted in the accumulation of PFAS in livestock. The environmental determinants of PFAS accumulation in livestock from the grazing environment are poorly understood, resulting in limited capacity to manage livestock exposure and subsequent transfer of PFAS through the food chain. Analytical- (n = 978 samples of soil, water, pasture, and serum matrices), farm management/practice- and livestock physiology data were collated and interrogated from environmental PFAS investigations across ten farms, from four agro-ecological regions of Victoria (Australia). Statistical analysis identified perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) as key analytes of concern for livestock bioaccumulation. PFOS and PFHxS concentrations in livestock drinking water were positively correlated with serum concentrations while other intake pathways (pasture and soil) had weaker correlations. Seasonal trends in PFAS body burden (serum concentrations) were identified and suggested to be linked to seasonal grazing behaviours and physiological water requirements. The data showed for the first time that livestock exposure to PFAS is dynamic and with relatively short elimination half-lives, there is opportunity for exposure management. Meat from cattle, grazed on PFAS impacted sites, may exceed health-based guideline values for PFAS, especially for markets with low limits (like the European Commission Maximum Limits or EC MLs). This study found that sites with mean livestock drinking water concentrations as low as 0.003 μg PFOS/L may exceed the EC ML for PFOS in cattle meat. Risk assessment can be used to prioritise site cleanup and development of management plans to reduce PFAS body burden by considering timing of stock rotation and/or supplementation of primary exposure sources.

Toxicity studies of sodium metavanadate and vanadyl sulfate administered in drinking water to Sprague Dawley (Hsd:Sprague Dawley SD) rats and B6C3F1/N mice.

Oral human exposure to vanadium may occur due to its presence in food and drinking water and its use in dietary supplements. The most prevalent oxidation states of vanadium in food and drinking water have been characterized as tetravalent and pentavalent. Vanadyl sulfate and sodium metavanadate were selected as representative tetravalent (V4+) and pentavalent (V5+) test articles for these studies, respectively. To assess the potential for oral toxicity of vanadium compounds with differing oxidation states under similar test conditions, the 3-month National Toxicology Program (NTP) toxicity studies of sodium metavanadate and vanadyl sulfate were conducted in male and female Sprague Dawley (Hsd:Sprague Dawley SD) rats (including perinatal exposure) and in B6C3F1/N mice. Drinking water concentrations for sodium metavanadate (0, 31.3, 62.5, 125, 250, and 500 mg/L) and vanadyl sulfate (0, 21.0, 41.9, 83.8, 168, and 335 mg/L) were selected on the basis of previously published 14-day drinking water studies conducted as part of the NTP vanadium research program. (Abstract Abridged).