Arsenic In Water Research Articles

A method to determine arsenic concentration in drinking water based on proton gradient and conductance measurements in filter paper media

This work describes a novel technique for the measurement of inorganic arsenic in water by generating arsine gas and detecting the conductivity of moving protons, H+ (aqueous or aq), produced by the reaction: Ag+ (aq) + AsH3 (gas, g) → AgAsH2 (solid, s) + H+ (aq). The detection is based on an electrochemical gradient of protons in a confined porous substrate (filter paper) and measures the change in the conductance due to the higher mobility of H+ compared to other ions. The conductance was measured with a pair of silver electrodes attached to opposite sides of the substrate with a bipolar pulse conductance technique. The method is established in theory and in practice. The theoretical equation for conductance change shows that a constant increase in conductance is directly proportional to the As(total) concentration. The method is validated with a standard reference material and applied to the measurement of the groundwater sample.

A Short Review on Fluoride and Arsenic Constituents in Nigerian Groundwater Networks: Causes, Effects and Suggested Removal Methods

The quality of water cannot be overlooked as it is an important element required by every being in existence. Water majorly is used as drinking water and if not properly looked after could lead to various health and environmental issues. Fluoride and arsenic are naturally occurring pollutants with their sources being traced to either anthropogenic or geogenic contributions. It is imperative to note that excessive consumption of fluoride and arsenic in water could result to serious health challenges. Elevated constituents of fluoride and arsenic in water have been reported in the northern and southern parts of Nigeria, but their concentrations are more prevalent in the north. The contaminants have been traced to some activities such as mining, improper disposal sites, agricultural practices, industrial effluents among others. Adsorption process has been suggested as the cost effective and environmentally friendly defluoridation, while nanofiltration membranes is the best removal process for arsenic in water.

Contamination and ecological risk assessment of Cr, As, Cd and Pb in water and sediment of the southeastern Bay of Bengal coast in a developing country

Safe levels of heavy metals in the surface water and sediment of the eastern Bay of Bengal coast have not been universally established. Current study characterized heavy metals such as arsenic (As), chromium (Cr), cadmium (Cd) and lead (Pb) in surface water and sediments of the most important fishing resource at the eastern Bay of Bengal coast, Bangladesh. Both water and sediment samples were analyzed using inductively coupled plasma mass spectrometer. Considering both of the seasons, the mean concentrations of Cr, As, Cd, and Pb in water samples were 33.25, 8.14, 0.48, and 21.14 μg/L, respectively and in sediment were 30.47, 4.48, 0.20, and 19.98 mg/kg, respectively. Heavy metals concentration in water samples surpassed the acceptable limits of usable water quality, indicating that water from this water resource is not safe for drinking, cooking, bathing, and any other uses. Enrichment factors also directed minor enrichment of heavy metals in sediment of the coast. Other indexes for ecological risk assessment such as pollution load index (PLI), contamination factor (CF), geoaccumulation index (Igeo), modified contamination degree (mCd), and potential ecological risk index (PERI) also indicated that sediment of the coastal watershed was low contamination. In-depth inventorying of heavy metals in both water and sediment of the study area are required to determine ecosystem health for holistic risk assessment and management.

Application of novel hot spring bacterial consortium in Arsenic (III) bioremediation: A model based approach for clean environment

The presence of arsenic in water poses a serious threat to both human health and natural systems, and is a global chronic issue. A comprehensive study on the water sample of Taptapani Hot Spring Odisha, India was carried out to isolate Arsenic (III) bioremediating microbial strains. 42 different bacterial isolates were screened and among them, phylogenetic analysis revealed the strains showing improved metal tolerance test adaptivity at various concentrations of Arsenic (III) to be closely related to Exiguobacterium sp. (SSB11), Alcaligenes faecalis DZ2 (SSB17) and Lysinibacillus sphaericus SI-3 (SSB58) and hence selected. The findings revealed that the consortium of thermophilic isolates was more effective at adsorbing Arsenic (III) than single isolates. The analysis of variance (ANOVA) revealed a significant coefficient of determination value and accurately forecast second order regression. The isotherm model had been applied for the first time to evaluate the arsenic adsorption efficacy of hot spring bacterial isolates, and the data were en suite to pseudo-first and second-order models. The kinetic data were fitted to Langmuir and Freundlich models. The most favorable elimination circumstances have been resolute and under optimal conditions, the adsorption of Arsenic (III) was found to be 50.28%.

Large Scale Nationwide Screening of Bioavailable Tetracyclines and Arsenic Using Whole-cell Bioreporter from Pangasius and Tilapia Aquaculture System in Bangladesh

In this study, a large-scale screening of bioavailable tetracycline (TC) and arsenic (As) was carried out using Whole-Cell biosensor bacteria from the pond surface waters of selected pangasius and tilapia farms across Bangladesh. Bioavailability of Tetracyclines and Arsenic was detected using biosensor bacteria E. coli K12 pTetLux1 and E. coli DH5R (pJAMA-arsR), respectively. 62 samples were within the tetracycline detection limit; others were below the detection limit. The highest concentration 31.27µg/l was found in a pond of Jashore and the lowest concentration 2.57µg/l, was measured from Trishal, Mymensingh. Tetracyclines were detected in 19.57 % of all analyzed samples and varied from below the detection limit to a maximum of 31.27 μg/l. Khulna showed the maximum percentage of detected samples (90%), followed by Mymensingh (52%), Cumilla (27.5%), Jashore (14%), Bogura (14%), and Sathkhira (10%). Bioavailable As were detected in only 5.7% of all analyzed samples. Detectable as samples were higher in number among the collected samples at Madaripur and higher in percentage at Sathkhira (30%) followed by Madaripur (20%), Cumilla (5%), and Gopalgonj (3.2%). The pick level of Arsenic was found in Madaripur, which was 9.45 µg/l and the lowest figure was 2.35 µg/l, found in Cumilla. Though the concentrations of arsenic in groundwater (tube well water) were high in all studied regions, the concentrations of arsenic in pond water were low in every region. The concentration of as in the experimental ponds was neither very high nor in the danger limit. Use of shallow tube well water, fertilizers, drugs, pesticides, and herbicides possessed with as during fish culture might be the source of as contamination. However, extensive use of antibiotics results in the emergence and spread of antibiotic resistance in the aquatic environment.

Arsenic levels in rice brands sold in Kampala: an experimental study to show the modifying effect of boiling, soaking and washing

Arsenic is an important environmental pollutant with potential cancer-causing effects. It contributes to acute and chronic toxicity depending on the doses or duration of exposure. In this study, we estimated the concentration of total arsenic in different rice brands sold in Uganda, where rice is a staple food. We conducted an experimental study. Different rice brands were obtained from supermarkets and grocery shops, and assessed for arsenic using atomic absorption spectrometry. The concentrations of arsenic in rice were estimated after boiling, washing, or overnight soaking in plenty of water to see if these methods reduce arsenic levels efficiently in food. The concentrations of arsenic in the different rice brands were compared using an unpaired t-test after setting a p-value of ≤0.05 as significant. The G-rice brand had the lowest arsenic levels of 1.4±0.0002 ppm and the C-rice brand had the highest levels of 2.4±0.004 ppm. The tap water used to boil, soak and wash the rice brands had much higher arsenic levels of 3.5±0.000003 ppm, leading to increased retention of the heavy metal in the rice. Rice brands sold in Kampala city seem to have higher than acceptable arsenic levels. Increased vigilance in terms of routine monitoring for the levels of arsenic in rice and water used during food preparation by the Ugandan food or water safety regulatory authorities is highly recommended.

Optimizations towards a nearly invariable WO3-functionalized electrochemical aptasensor for ultra-trace identification of arsenic in lake water

Prolonged exposure to elevated levels of arsenic in water can lead to serious health problems and its efficient detection is vital for preventing acute arsenic poisoning incidents. The nanomaterial based electrochemical detection offers advantages in terms of high sensitivity, selectivity, and potential for compact, portable testing systems; albeit suffers from inter-device variability. This work presents a highly sensitive aptamer-based nano-biosensor for efficiently detecting arsenic in water through the electrochemical method using glassy carbon electrodes modified with tungsten trioxide (WO3) nanomaterial. The aptasensor in conjunction with electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) techniques is employed for detection of As(III) in de-ionised and lake water. To ensure reliability, rigorous optimization was conducted to achieve near uniformity in the adhesion of the nanomaterial dispersion. The designed sensor's detection limit is 1.12 nM and 0.76 nM for DPV and EIS methods respectively, well below the safe limit of 10 µg/L (∼133 nM). The sensitivity obtained using EIS is 22.5 µM-1 cm-2, and the sensor has a shelf life of 30 days. The proposed methodology can be applied to assess water toxicity without releasing any secondary toxins into the environment and can be coupled with a miniaturized sensing system for enhanced environmental monitoring.

Using an anti-fouling electro- (stainless-steel/ PVC) membrane reactor in electrocoagulation process for arsenic removal: Experimental study and mechanism development in multiphase media using CFD

The electrocoagulation (EC) method is an effective way to remove arsenic (As) from water. However, to obtain high-quality floc-free water, it needs further purification, and membrane processes can be used to achieve this goal, but fouling is their main problem. In this study, a PVC/stainless steel electro-conductive membrane was used as a cathode electrode, and the effects of voltage, current, and time on the reduction of membrane fouling and arsenic removal were investigated. By increasing the applied voltage, due to the increase of the repulsive force between the membrane and negatively charged arsenic particles, the percentage of arsenic removal increased. While increasing the current density, more coagulant materials were produced from the anode, and the rejection rate of arsenic also became higher. The optimal conditions for removing arsenic at 22 V, 0.2 A, and 50 min were obtained according to the box-Behnken design in deionized water. After the second one-hour cycle, the concentration of arsenic in the model water decreased by 99.6% and fell below the maximum permissible level. Additionally, increasing voltage and current reduces membrane fouling due to an increase in the repulsive force and formation of bubbles on the membrane surface, respectively. Also, the process modeling results, considering the adsorption mechanism and repulsive force, showed that at 0.2 and 0.32 amperages, the model follows the Freundlich and Langmuir isotherms better, respectively, and showed an accurate prediction of experimental outcomes. Furthermore, 3D process modeling results indicated the distribution of velocity, current, voltage, and concentration inside the reactor.

Heavy metal levels in the dairy production chain in China

AbstractThe aims of this study were to investigate the heavy metal pollution status and distribution and to analyze the relationships among metal concentrations of different links in the dairy production chain. Chromium (Cr), arsenic (As), cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) levels in water, fodder, milk, blood, hair, and feces samples collected from cows from five dairy farms in China were measured. The concentrations of Cr, As, Cd, Pb, Cu, and Zn were 4.61–11.11, 0.06–0.46, 0.17–0.29, 2.84–4.23, 4.11–7.72, and 7.23–19.91 mg/kg in silage; 12.72–40.85, 0.76–2.40, 0.05–0.16, 4.73–9.16, 44.14–78.46, and 4148.51–4845.20 μg/L in milk; 33.59–60.73, 0.09–3.57, 0.29–1.78, 20.14–39.20, 821.34–1007.45, and 2665.10–4929.95 μg/L in blood; 0.59–1.06, 0.02–0.09, 0.08–0.11, 1.70–2.09, 6.45–8.64, and 9.73–1.56 mg/kg in hair; 31.75–296.35, 0.33–5.96, 0.18–0.53, 3.35–9.06, 12.27–41.39, and 56.54–196.34 mg/kg in feces, respectively. The concentrations of heavy metals in hair were higher than those in the other samples and when combined with the results from the silage and tissue samples, we can assume that cow's hair can be used as a biological indicator for heavy metal contamination in the dairy production chain.

Heavy metal contamination and risk assessment on ecological and public health in a tropical estuarine river

Heavy metals contamination of water is one of the most severe environmental and public health issues. The present study was conducted to assess the levels of lead (Pb), chromium (Cr), cadmium (Cd), arsenic (As), copper (Cu) and zinc (Zn) in surface water of the Pasur River estuary in Bangladesh along with their health risk through the ingestion and dermal exposure. The decreasing order of studied metals was Cr > Pb >Cu > Zn > As > Cd with the mean value of 0.050 > 0.024 > 0.021 > 0.014 > 0.012 > 0.006 mg/L respectively. Pb, Cr, Cd and Zn concentration in water samples exceeded the safe limits of drinking water and thereby not safe for drinking. The multivariate analysis identified the common anthropogenic source and existence of studied metals. Heavy metal pollution index (HPI) and heavy metal evaluation index (HEI) indicated significant contamination of water. The HQ and HI through ingestion and dermal contact were <1 except for the adult, whereas HQ (only for As) and HI value through ingestion was >1 indicating an unacceptable risk of non-carcinogenic effects on public health. Carcinogenic risk through ingestion (CRing) indicated that consumption of water from Pasur River estuary may develop cancer risk of Cd. Therefore, strict rules and regulations must be adopted to reduce water contamination of this tidal river from anthropogenic sources for improving the health of this riverine ecosystem.

Low-to-Moderate Arsenic Exposure and Urothelial Tract Cancers with a Long Latent Period of Follow-Up in an Arseniasis Area

BackgroundArsenic exposure can cause adverse health effects. The effects of long-term low-to-moderate exposure and methylations remain unclear.ObjectiveThis study aims to examine the association between low-to-moderate arsenic exposure and urothelial tract cancers while considering the effects of methylation capacity.MethodsIn this study, 5,811 participants were recruited from an arseniasis area in Taiwan for inorganic arsenic metabolite analysis. This follow-up study was conducted between August 1995 and December 2017. We identified 85 urothelial tract cancers in these participants, including 49 bladder and 36 upper urothelial tract cancer cases. A Cox proportional hazards model was employed.ResultsThe analyses revealed a significant association between concentrations of inorganic arsenic in water > 100 ug/L and bladder cancer occurrence, with a hazard ratio (HR) of 4.88 (95% CI 1.35–17.61). A monotonic trend was observed between concentrations of inorganic arsenic in water (from 0 to > 100 ug/L) and the incidence of urothelial tract cancer, including bladder cancer (p < 0.05) and upper urothelial tract cancers (p < 0.05). Participants with a lower primary methylation index or higher secondary methylation index had a prominent effect.ConclusionsRigorous regulations and active interventions should be considered for populations with susceptible characteristics.

Association of water arsenic and uranium exposures with incident diabetes in Indigenous US communities: The Strong Heart Study

Association of water arsenic and uranium exposures with incident diabetes in Indigenous US communities: The Strong Heart Study

Meta-analysis of the relationship between maternal arsenic exposure and preterm birth

To systematic evaluate the association between maternal arsenic exposure and preterm birth. A literature search was conducted through Pubmed, Web of Science, Embase, China Knowledge Network(CNKI), WanFang Data, Vip Chinese Journal Service Platform(VIP) with a time frame of November 2022 from the beginning of database construction. Meta-analysis of dichotomous variables was performed using Stata MP15 software, and a random or fixed effects model was chosen for the meta-analysis based on the heterogeneity result, with the ratio of ratios(OR) as the effect indicator; subgroup analysis was used to find characteristic changes; funnel plots were used to evaluate publication bias. A total of 15 papers with a sample size of(n=9 892 256 279), 10 prospective cohort studies, 3 retrospective cohort studies, and 2 cross-sectional studies, were included in 6 Chinese and 9 English papers. By Meta-analysis, the combined OR of preterm birth outcome was 1.06(95%CI 1.03-1.09); the result of subgroup analysis by exposure factors and region, the combined OR(95%CI) of hair, blood, urine, drinking water, and placenta were 0.97(0.56-1.69), 1.40(1.22-1.60), 1.04(0.93-1.17), 1.14(1.04-1.24) and 0.69(0.07-6.38). The combined OR(95%CI) were 1.17(1.04-1.31), 1.10(1.05-1.14), 0.69(0.07-6.38) and 1.17(1.01-1.36) for Asia, Americas, Europe and Africa, respectively. For subgroup analysis based on study type, the combined OR(95%CI) was 1.16(1.05-1.28), 1.01(1.01-1.02) and 1.65(0.73-3.74) for prospective cohort studies, retrospective cohort studies, and cross-sectional studies, respectively. Maternal arsenic exposure may contribute to the occurrence of preterm birth, and drinking water arsenic levels may be an important indicator for assessing human arsenic exposure and risk of causing preterm birth.

Towards an understanding of the factors controlling bacterial diversity and activity in semi-passive Fe: and As-oxidizing bioreactors treating arsenic-rich acid mine drainage.

Semi-passive bioreactors based on iron and arsenic oxidation and co-precipitation are promising for the treatment of As-rich acid mine drainages. However, their performance in the field remains variable and unpredictable. Two bioreactors filled with distinct biomass carriers (plastic or a mix of wood and pozzolana) were monitored during one year. We characterized the dynamic of the bacterial communities in these bioreactors, and explored the influence of environmental and operational drivers on their diversity and activity. Bacterial diversity was analyzed by 16S rRNA gene metabarcoding. The aioA genes and transcripts were quantified by qPCR and RT-qPCR. Bacterial communities were dominated by several iron-oxidizing genera. Shifts in the communities were attributed to operational and physiochemical parameters including the nature of the biomass carrier, the water pH, temperature, arsenic and iron concentrations. The bioreactor filled with wood and pozzolana showed a better resilience to disturbances, related to a higher bacterial alpha diversity. We evidenced for the first time aioA expression in a treatment system, associated with the presence of active Thiomonas spp. This confirmed the contribution of biological arsenite oxidation to arsenic removal. The resilience and the functional redundancy of the communities developed in the bioreactors conferred robustness and stability to the treatment systems.

Iron and aluminum based beaded sorbents for removing arsenic and fluorine from water: Application of machine learning for material selection

In this study, the waste reuse of water purification plant sludge (WPS) and coal mine drainage sludge (CMDS) was carried out and synthesized into beaded adsorbents BWPS and BCMDS. The WPS is rich in aluminum, and the aluminum-based adsorbent has a good adsorption effect on the fluoride in water. CMDS is rich in iron and calcium, arsenic can be removed from water using this device. The experiments mainly probed the pollutant-removing effects of two beaded adsorbents on fluoride and arsenic in water. According to the Langmuir isotherm equation, the maximum adsorption capacities (Qmax) of F- on BWPS and BCMDS are 0.90 and 0.65 mg g−1, and the Qmax of As (V) are 9.87 and 14.88 mg g−1, respectively. With a range of pH 4 ∼ 10 in experiments, increasing pH decreased the pseudo-second-order rate (K2) of F- and As(V) adsorbed on the beaded adsorbents. The mechanism for removing F- by BWPS is physical adsorption, on BCMDS are ion exchange and precipitation, and for As(V) are physisorption and precipitation. In the desorption experiments, the results indicated that both adsorbents can be reused. In addition, it is combined with XGBoost and SHapley Additive exPlanations (SHAP), to predict the adsorption capacity. Data preprocessing and model training improved the prediction accuracy, resulting in a final RMSE of 0.429 and an average prediction accuracy of 91%. Through the evaluation index (EI) select the final adsorbent, the results showed that the choice of adsorbent was unchanged in general conditions and expert surveys, however, in some specific scenarios can be changed.

Shipboard determination of arsenite and total dissolved inorganic arsenic in estuarine and coastal waters with an automated on-site-applicable atomic fluorescence spectrometer

The speciation of trace level arsenic (As) in estuarine and coastal waters is crucial for both biogeochemical and toxicological studies of this toxic metalloid. However, the accurate and on-site determination of As in complex seawater matrices is challenging because of the low concentration of As, the easy conversion of arsenite (As(III)) to arsenate (As(V)), and the considerable effect of salinity on the determination of As via conventional methods. In this study, a custom-made shipboard atomic fluorescence spectrometer (AFS) is reported for the on-site speciation of inorganic As in estuarine and coastal waters. After comprehensive optimization of the instrumental and chemical parameters, the method demonstrated high sensitivity (limits of detection: 0.02 μg L−1), good linearity (R2 > 0.999 for all calibration curves up to 8 μg L−1), high precision (relative standard deviations (RSDs) of less than 2% at 1 μg L−1 over a year-long evaluation), and excellent performance for sample analysis for different matrices with varying salinities (recoveries: 96.3%–105.3%). The portable and field-applicable AFS was successfully applied to the on-site and shipboard simultaneous determination of As(III) and total dissolved inorganic arsenic (TDIAs) in the coastal waters of Shandong, Jiangsu, Zhejiang, Fujian, and Guangdong province of China, demonstrating its robustness and applicability in harsh conditions.

An updated systematic review and dose-response meta-analysis on the relation between exposure to arsenic and risk of type 2 diabetes

Arsenic is among the most critical environmental toxicants associated with many human disorders. However, its effect on type 2 diabetes mellitus (T2DM) is contradictory. This systematic review and dose-response meta-analysis aim to update information on the association between arsenic exposure and the risk of T2DM. The sample type (drinking water, urine, blood, and nails) conducted the subgroup analysis. Evaluation of the high vs. low arsenic concentrations showed a significant association between drinking water arsenic (OR: 1.58, 95% CI: 1.20–2.08) and urinary arsenic (OR: 1.37, 95% CI: 1.24–1.51) with the risk of T2DM. The linear dose-response meta-analysis showed that each 1 μg/L increase in levels of drinking water arsenic (OR: 1.01, 95% CI: 1.00–1.01) and urinary arsenic (OR: 1.01, 95% CI: 1.00–1.02) was associated with a 1% increased risk of T2DM. The non-linear dose-response analysis indicated that arsenic in urine was associated with the risk of T2DM (Pnon-linearity<0.001). However, this effect was not statistically significant for arsenic in drinking water (Pnon-linearity=0.941). Our findings suggest that blood arsenic was not significantly linked to the increased risk of T2DM in high vs. low (OR: 1.21, 95% CI: 0.85–1.71), linear (OR: 1.04, 95% CI: 0.99–1.09), and non-linear (Pnon-linearity=0.365) analysis. Also, nail arsenic was not associated with the risk of T2DM in this meta-analysis (OR: 1.33, 95% CI: 0.69–2.59). This updated dose-response meta-analysis indicated that arsenic exposure was significantly correlated with the risk of T2DM.

A self-powered electro-coagulation system afforded by flexible electromagnetic flag wind generators for efficient removal of arsenic from water

In the past few years, human activities, such as mining and metallurgical industries, have made the arsenic concentration in natural waters elevate. To provide clean and safe water to people worldwide, tremendous endeavors have been made to accomplish low-cost and effective treatment of arsenic-containing water. Among the methods employed, electro-coagulation has been the one that stands out attributable to its high efficiency and low cost. However, its high energy consumption has become an obstacle to further applications, particularly in the regions where electricity is limited. Here, an innovative self-powered electro-coagulation system (SPECS) driven by flexible electromagnetic flag wind generators (FEFWGs) is developed to realize the power-free removal of dissolved arsenic in water. The FEFWGs exhibit an excellent output performance under a moderate wind speed (6.3 m s−1), with a peak open-circuit voltage of 3.7 V and a peak short-circuit current of 13.6 mA. Using the SPECS to purify polluted water, a large volume of wastewater containing 5 ppm of arsenic can be purified with our SPECS in 20 min, which is more efficient than that of existing reports.

The human right to safe drinking water and sanitation. Comparative analysis from capabilities

This study answers the question: how does the Human Right to Water and Sanitation (HRWS) materialize in the municipality of Tlajomulco, Jalisco, Mexico? and for this, the cases of two antagonistic housing developments are compared in the context of the unplanned urban growth dissociated from water management practices that prevailed throughout the country: Nueva Galicia and Silos. The first housing development evidenced problems in 2014 due to the presence of arsenic in water for domestic use above the official Mexican standard (NOM-127-SSA1-1994), which was resolved in less than a year. Thesecond development suffered from intermittent service of water of dubious quality, since 2007 that has not been resolved. This despite the fact that both developments share the same basin, the same aquifer and the same political-administrative delimitation. The methodology employed was based on three levels of analysis: city, neighborhood and domestic space, these scales summon each other and their relationships and urban dynamics are juxtaposed as layers of reality. The domestic scale is considered as a materialization space, through intense ethnographic work, of the HRWS discourse. Elements of thecapabilities approach were used, which allows analyzing the differences in terms of access to water, in the words of Nussbaum (2012): in terms of failures and omissions that are due to the presence of discrimination, where the State, due to their practices and relationships, provides water to some groups and not to others.

Anthropometric measures and arsenic methylation among pregnant women in rural northern Bangladesh

IntroductionArsenic methylation converts inorganic arsenic (iAs) to monomethyl (MMA) and dimethyl (DMA) arsenic compounds. Body mass index (BMI) has been positively associated with arsenic methylation efficiency (higher DMA%) in adults, but evidence in pregnancy is inconsistent. We estimated associations between anthropometric measures and arsenic methylation among pregnant women in rural northern Bangladesh. MethodsWe enrolled pregnant women (n = 784) (median [IQR] gestational week: 14 [13, 15]) in Gaibandha District, Bangladesh from 2018 to 2019. Anthropometric measures were BMI, subscapular and triceps skinfold thicknesses, and mid-upper arm circumference (MUAC), fat area (MUAFA), and muscle area (MUAMA). Arsenic methylation measures were urinary iAs, MMA, and DMA divided by their sum and multiplied by 100 (iAs%, MMA%, and DMA%), primary methylation index (MMA/iAs; PMI), and secondary methylation index (DMA/MMA; SMI). In complete cases (n = 765 [97.6%]), we fitted linear, beta, and Dirichlet regression models to estimate cross-sectional differences in iAs%, MMA%, DMA%, PMI, and SMI per IQR-unit difference in each anthropometric measure, adjusting for drinking water arsenic, age, gestational age, education, living standards index, and plasma folate, vitamin B12, and homocysteine. ResultsMedian (IQR) BMI, subscapular skinfold thickness, triceps skinfold thickness, MUAC, MUAFA, and MUAMA were 21.5 (19.4, 23.8) kg/m2, 17.9 (13.2, 24.2) mm, 14.2 (10.2, 18.7) mm, 25.9 (23.8, 28.0) cm, 15.3 (10.5, 20.3) cm2, and 29.9 (25.6, 34.2) cm2, respectively. Median (IQR) iAs%, MMA%, DMA%, PMI, and SMI were 12.0 (9.3, 15.2)%, 6.6 (5.3, 8.3)%, 81.0 (77.1, 84.6)%, 0.6 (0.4, 0.7), and 12.2 (9.3, 15.7), respectively. In both unadjusted and adjusted linear models, all anthropometric measures were negatively associated with iAs%, MMA%, and PMI and positively associated with DMA% and SMI. For example, fully adjusted mean differences (95% CI) in DMA% per IQR-unit difference in BMI, subscapular skinfolds thickness, triceps skinfold thickness, MUAC, MUAFA, and MUAMA were 1.72 (1.16, 2.28), 1.58 (0.95, 2.21), 1.74 (1.11, 2.37), 1.45 (0.85, 2.06), 1.70 (1.08, 2.31), and 0.70 (0.13, 1.27) pp, respectively. ConclusionsAnthropometric measures were positively associated with arsenic methylation efficiency among pregnant women in the early second trimester.