Arsenic-contaminated Areas Research Articles

NATURAL EXPOSURE TO ARSENIC-INDUCED GENOTOXIC EFFECTS IN DIABETIC AND NON-DIABETIC INDIVIDUALS

Arsenic contamination in drinking water is a global health issue linked to various adverse health outcomes, including genotoxic effects. Understanding these effects in different populations, including diabetic and non-diabetic individuals, is critical for developing targeted public health interventions. Objective: This study aimed to investigate the genotoxic effects of arsenic exposure in diabetic and non-diabetic individuals residing in arsenic-contaminated and control areas. Methods: In this cross-sectional study conducted from January to June 2024, 100 participants were recruited from areas with known differences in arsenic water contamination levels. Participants were divided equally between arsenic-contaminated and non-contaminated regions, with 15 diabetic and 20 non-diabetic individuals selected from each group. A standard questionnaire was administered to collect demographic data and medical history. Additionally, 12 water samples from the contaminated area were analyzed for arsenic concentration. Genotoxic effects were assessed using the comet assay, and DNA damage was quantified using an empirical numerical rating system. Results: Significant DNA damage was observed in the blood cells of individuals from the arsenic-contaminated area compared to those from the non-contaminated area. Diabetic individuals showed similar patterns of DNA damage to non-diabetics within the same exposure group. Even in the non-contaminated group, slight DNA damage was detected, suggesting potential contributions from other environmental factors. Conclusion: The findings demonstrate that arsenic exposure is associated with significant genotoxic effects in both diabetic and non-diabetic populations. DNA damage in non-contaminated areas also indicates a possible impact of other environmental factors. These results highlight the need for ongoing monitoring and mitigation strategies to address arsenic contamination and its health impacts.

How do households living in arsenic-contaminated regions value safe drinking water in western Bihar, India?

Access to safe drinking water is a critical concern, particularly in areas affected by arsenic contamination. In Bihar, an Indian state, 13 districts are facing groundwater contamination. The report of Ministry of Jal Shakti, Government of India (2021), reveals that about 24 habitations from five districts of Bihar are affected by arsenic groundwater contamination, impacting about 71,946 population and their health and economic conditions. The objectives of the present study are to determine factors that impact households' WTP for arsenic-free drinking water and estimate the mean willingness to pay (WTP) for arsenic-free drinking water. The primary data from 300 households was collected following simple random sampling, and villages were selected through a multi-stage sampling method. The study uses a single-bound dichotomous choice method for WTP elicitation and applies a probit model to determine factors affecting households' WTP for arsenic-free safe drinking water. The mean WTP is estimated to be ₹ 216.68 per household/month, and results find that education, income, health expenditure, awareness level and high-risk exposure to arsenic are the most influential determinants of households’ WTP for arsenic-free drinking water. The influence of education and awareness level is positive, calling for conducting more awareness programs in the arsenic-contaminated areas in Bihar.

Modelling the impact of different irrigation regimes and mulching on strawberry crop growth and water use in the arsenic-contaminated Bengal basin

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.

Arsenic stress on soil microbial nutrient metabolism interpreted by microbial utilization of dissolved organic carbon

In a 120-day microcosm incubation experiment, we investigated the impact of arsenic contamination on soil microbial nutrient metabolism, focusing on carbon cycling processes. Our study encompassed soil basal respiration, key enzyme activities (particularly, β-1,4-N-acetylglucosaminidase and phosphatases), microbial biomass, and community structure. Results revealed a substantial increase (1.21–2.81 times) in β-1,4-N-acetylglucosaminidase activities under arsenic stress, accompanied by a significant decrease (9.86%−45.20%) in phosphatase activities (sum of acid and alkaline phosphatases). Enzymatic stoichiometry analysis demonstrated the mitigation of microbial C and P requirements in response to arsenic stress. The addition of C-sources alleviated microbial C requirements but exacerbated P requirements, with the interference amplitude increasing with the complexity of the C-source. Network analysis unveiled altered microbial nutrient requirements and an increased resistance process of microbes under arsenic stress. Microbial carbon use efficiency (CUE) and basal respiration significantly increased (1.17–1.59 and 1.18–3.56 times, respectively) under heavy arsenic stress (500 mg kg−1). Arsenic stress influenced the relative abundances of microbial taxa, with Gemmatimonadota increasing (5.5–50.5%) and Bacteroidota/ Nitrospirota decreasing (31.4–47.9% and 31.2–63.7%). Application of C-sources enhanced microbial resistance to arsenic, promoting cohesion among microorganisms. These findings deepen our understanding of microbial nutrient dynamics in arsenic-contaminated areas, which is crucial for developing enzyme-based toxicity assessment systems for soil arsenic contamination.

From ground to gut: Evaluating the human health risk of potentially toxic elements in soil, groundwater, and their uptake by Cocos nucifera in arsenic-contaminated environments

This study aimed to gauge the toxicity of potentially toxic elements (PTEs) in coconut crops cultivated in arsenic-contaminated areas while offering a global perspective encompassing more than 100 impacted countries. The current investigation provides crucial insights into the assessment of PTEs pollution using the Bioaccumulation factor, Geo-accumulation index, Potential ecological risk index, Hazardous index, and Lifetime cancer risk (LCR) and highlights the potential human health risks posed by contaminated food, water, and soil. From 22 severely polluted sites in West Bengal, India, soil, groundwater (GW), and coconut water (CW) samples were collected, acidified, and digested using microwave digestion, for PTEs quantification using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results revealed that despite high concentrations of arsenic in soils (4.6 ± 3.4 mg kg−1), and GW (22.2 ± 150.9 μg L−1), CW (0.7 ± 3.1 μg L−1) levels were within permissible limits. Groups of PTEs with comparable sources and distributions were discovered through Principal Component Analysis (PCA). A speciation diagram was used to predict the prevalence of arsenic species in all three matrices. The Hazardous Index (HI < 1) indicated no probability of non-carcinogenic diseases for children and adults in all the compartments. However, exposure to GW and soil contaminated with Cr, As, and Cd by children (9.02 × 10−13 to 2.77 × 10−4) and adults (6.51 × 10−14 to 1.18 × 10−4) would increase their susceptibility to cancer (LCR >10−6). The study concluded that moderate lifetime consumption of CW is safe and has no significant impact on healthy individuals. Additionally, CW is a rich source of essential micronutrients such as Zn, Fe, Mn, and B. Overall, the findings of this study could help in developing appropriate strategies for reducing PTEs contamination and protecting human health.

Suppressed Histone H3 Lysine 18 Acetylation Is Involved in Arsenic-Induced Liver Fibrosis in Rats by Triggering the Dedifferentiation of Liver Sinusoidal Endothelial Cells.

Arsenic pollution is a global environmental concern. Arsenic-induced chronic liver injury and its irreversible outcomes, including liver cirrhosis and liver cancer, threaten the health of residents in arsenic-contaminated areas. Liver fibrosis is a reversible pathological stage in the progression of arsenic-induced chronic liver injury to cirrhosis and liver cancer. The aim of this study is to identify the epigenetic mechanism of arsenic-induced liver fibrosis based on the dedifferentiation of liver sinusoidal endothelial cells (LSECs). Rats were treated with 0.0, 2.5, 5.0, or 10.0 mg/kg sodium arsenite for 36 weeks. Marked fibrotic phenotypes were observed in the rat livers, manifested by hepatic stellate cell activation and an increased extracellular matrix, as well as the deposition of collagen fibers. The reduced fenestrations on the cells' surface and the increased expression of the dedifferentiation marker CD31 corroborated the LSECs' dedifferentiation in the liver tissue, which was also found to be significantly associated with fibrotic phenotypes. We further revealed that arsenic exposure could inhibit the enrichment of histone H3 lysine 18 acetylation (H3K18ac) in the promoters of Fcgr2b and Lyve1, two key genes responsible for maintaining the differentiation phenotype of LSECs. This inhibition subsequently suppressed the genes' expression, promoting LSEC dedifferentiation and subsequent liver fibrosis. In conclusion, arsenic can trigger liver fibrosis by inhibiting H3K18ac-dependent maintenance of LSEC differentiation. These findings uncover a novel mechanism of arsenic-induced liver fibrosis based on a new insight into epigenetically dependent LSEC dedifferentiation.

Replacing conventional surface irrigation with micro-irrigation in vegetables can alleviate arsenic toxicity and improve water productivity

Arsenic (As), a heavy metal(loid), is exceedingly hazardous and carcinogenic and harms people, soil, plants, and water. Vegetable consumption can be a source for the absorption of As in humans. To find a feasible mitigation technique, a field experiment was conducted with broccoli (cv. Green Magic) and cauliflower (cv. Pusa Snowball) in geogenically arsenic-contaminated areas (West Bengal, India) for two consecutive years in a randomized block design replicated seven times with surface irrigation of 20 mm depth, gravity drip and sprinkler irrigation at 1.0 and 0.7 of pan evaporation replenishment. Results revealed that the lowest As accumulation in the edible heads was accomplished by micro-irrigation (0.34 and 0.31 mg kg−1) over the farmer's practice of surface irrigation (0.42 and 0.38 mg kg−1) for broccoli and cauliflower. Micro-irrigation improved the average head yield by 5.26 and 6.53%, weight by 6.37 and 3.06%, and diameter by 1.14 and 1.23% for broccoli and cauliflower respectively and also resulted in substantial water saving to an extent of 37.3%. Further reduction in As stress reduced the activity of antioxidant enzymes like catalase, superoxide dismutase and peroxidase; and reduced the dietary carcinogenic risk like Severity Adjusted Margin of Exposure (SAMOE) from moderate-high to low. Accordingly, drip irrigation without water stress can benefit vegetable growing in the As-contaminated regions based on the competitive advantage.

Genotoxic Effects of Arsenic in Food-Crops: A Need for Transgenerational Studies

Groundwater arsenic contamination has impacted millions of lives in over 100 countries; India and Bangladesh are the foremost victims. Arsenic contamination of food materials, especially rice, the staple food, is the biggest concern in these regions. Arsenic-tolerant rice varieties can help protect millions of impoverished people in arsenic-affected areas. However, transgenerational studies on the impact of arsenic on rice varieties over generations are highly neglected. This article highlights the need for transgenerational studies in arsenic-contaminated areas. A few rice varieties have shown tolerance to arsenic that could be explored to investigate whether these varieties can be sufficiently tolerant if they continue to be grown in an arsenic environment for a few consecutive generations. Transgenerational or epigenetics studies, therefore, are vital in protecting millions of human lives

Arsenic in mind: Construction of knowledge and attitude scales

Chronic arsenic toxicity (arsenicosis) as a result of drinking arsenic-contaminated groundwater is a major environmental health hazard throughout the world, including India. During the last four decades arsenic contamination of groundwater in nine districts out of twenty in West Bengal has become a serious problem. About 20% population of West Bengal in nine districts (Malda, Murshidabad, Nadia, North 24- Parganas, and South 24-Parganas, Kolkata, Howrah, Hooghly and Burdwan) are affected by arsenic problem. To prevent this harmful effect, every people need to have proper knowledge and positive attitude towards arsenic. In this study, the researcher constructed a standardized tool of knowledge and attitude towards arsenic to assess the knowledge and attitude level of arsenic among the people of arsenic contaminated area. The researcher took item analysis method to assess the quality of the items of every section. Then the tools were measured the reliability by the Pearson’s product moment correlation method. Primarily two self-administered tools of 39 knowledge items and 32 attitude items regarding arsenic was applied among the people of Nadia district of West Bengal. Therefore, the researcher analyzed the collecting data and eliminated the poor items on the basis of difficulty value and discrimination index. After elimination of distracting items, 25 items in knowledge section and 25 items in the attitude section were retained as a final form of tool regarding arsenic. Thereafter the final form of tools applied among 60 general people to calculate the reliability of the tools by test-retest reliability method. The researcher found significant reliability in knowledge and attitude tools. These standard tools can assess the knowledge and attitude level regarding arsenic among the people of arsenic contamination area with accuracy.

Effects of chronic exposure to arsenic on the fecal carriage of antibiotic-resistant Escherichia coli among people in rural Bangladesh.

Antibiotic resistance is a leading cause of hospitalization and death worldwide. Heavy metals such as arsenic have been shown to drive co-selection of antibiotic resistance, suggesting arsenic-contaminated drinking water is a risk factor for antibiotic resistance carriage. This study aimed to determine the prevalence and abundance of antibiotic-resistant Escherichia coli (AR-Ec) among people and drinking water in high (Hajiganj, >100 μg/L) and low arsenic-contaminated (Matlab, <20 μg/L) areas in Bangladesh. Drinking water and stool from mothers and their children (<1 year) were collected from 50 households per area. AR-Ec was detected via selective culture plating and isolates were tested for antibiotic resistance, arsenic resistance, and diarrheagenic genes by PCR. Whole-genome sequencing (WGS) analysis was done for 30 E. coli isolates from 10 households. Prevalence of AR-Ec was significantly higher in water in Hajiganj (48%) compared to water in Matlab (22%, p <0.05) and among children in Hajiganj (94%) compared to children in Matlab (76%, p <0.05), but not among mothers. A significantly higher proportion of E. coli isolates from Hajiganj were multidrug-resistant (83%) compared to isolates from Matlab (71%, p <0.05). Co-resistance to arsenic and multiple antibiotics (MAR index >0.2) was observed in a higher proportion of water (78%) and child stool (100%) isolates in Hajiganj than in water (57%) and children (89%) in Matlab (p <0.05). The odds of arsenic-resistant bacteria being resistant to third-generation cephalosporin antibiotics were higher compared to arsenic-sensitive bacteria (odds ratios, OR 1.2-7.0, p <0.01). WGS-based phylogenetic analysis of E. coli isolates did not reveal any clustering based on arsenic exposure and no significant difference in resistome was found among the isolates between the two areas. The positive association detected between arsenic exposure and antibiotic resistance carriage among children in arsenic-affected areas in Bangladesh is an important public health concern that warrants redoubling efforts to reduce arsenic exposure.

Comparative Biomonitoring of Arsenic Exposure in Mothers and Their Neonates in Comarca Lagunera, Mexico

Multiple comorbidities related to arsenic exposure through drinking water continue to be public problems worldwide, principally in chronically exposed populations, such as those in the Comarca Lagunera (CL), Mexico. In addition, this relationship could be exacerbated by an early life exposure through the placenta and later through breast milk. This study conducted a comparative analysis of arsenic levels in multiple biological samples from pregnant women and their neonates in the CL and the comparison region, Saltillo. Total arsenic levels in placenta, breast milk, blood, and urine were measured in pregnant women and their neonates from rural areas of seven municipalities of the CL using atomic absorption spectrophotometry with hydride generation methodology. The average concentrations of tAs in drinking water were 47.7 µg/L and 0.05 µg/L in the exposed and non-exposed areas, respectively. Mean levels of tAs were 7.80 µg/kg, 77.04 µg/g-Cr, and 4.30 µg/L in placenta, blood, urine, and breast milk, respectively, in mothers, and 107.92 µg/g-Cr in neonates in the exposed group, which were significantly higher than those in the non-exposed area. High levels of urinary arsenic in neonates were maintained 4 days after birth, demonstrating an early arsenic exposure route through the placenta and breast milk. In addition, our study suggested that breastfeeding may reduce arsenic exposure in infants in arsenic-contaminated areas. Further studies are necessary to follow up on comorbidities later in life in neonates and to provide interventions in this region.

Highly sensitive detection of arsenic in groundwater by paper-based electrochemical sensor modified with earth-abundant material

The toxicity of arsenic and its hazards to the human body are well known and its timely, accurate, and cost-effective detection in water and foodstuffs and other environmental matrices is highly essential. Herein, we present a simple and easy method for the synthesis of reduced graphene oxide-ceria (rGO-CeO2) nanocomposite and its use for low-level detection of As(III) in water up to 0.93 μg/L. The presence of CeO2 on rGO surface is attributed to the enhanced electron transfer rate. The material characterization was performed with different analytical techniques including scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD), Infrared spectroscopy (FTIR) and Electrochemical Impedance Spectroscopy (EIS). The electrochemical behaviour of the rGO-CeO2 modified screen-printed electrodes (SPE) has been investigated by using Cyclic Voltammetry (CV) and Differential Pulse Stripping Voltammetry (DPSV). A highly linear response with a correlation coefficient of 0.9986 is achieved with a detection limit of 0.39 μg/L. Finally, the sensor was also tested with real-world groundwater samples collected from the arsenic-contaminated areas and acceptable recoveries were observed in the range of 85–95% as compared to Inductively Coupled Plasma Mass Spectrometer (ICP-MS) analysis. The electroanalytical performances of rGO-CeO2 modified SPE confirm that the as prepared sensor can be used for practical applications owing to its high sensitivity, good selectivity, robustness, low cost, high reproducibility, reusability, and ease of high scale production.

The complete chloroplast genome of Isatis cappadocica Desv. (Brassicaceae)

Isatis cappadocica Desv. is a vigorous perennial rosette plant and it can grow in highly arsenic-contaminated areas. In this study, the complete chloroplast genome of I. cappadocica was assembled and annotated. The total length of this genome is 153,800 bp and the GC content is 36.48%. It has a typical four-part structure: a pair of inverted repeat sequences (26,270 bp each), a small single-copy region (17,715 bp), and a large single-copy region (83,545 bp). The annotation results show that it contains 132 genes. The phylogenetic analysis of I. cappadocica and other 18 representative plants indicates that I. cappadocica is closely related to Isatis tinctoria.

Developmental arsenic exposure impairs cognition, directly targets DNMT3A, and reduces DNA methylation.

Developmental arsenic exposure has been associated with cognitive deficits in epidemiological studies, but the underlying mechanisms remain poorly understood. Here, we establish a mouse model of developmental arsenic exposure exhibiting deficits of recognition and spatial memory in the offspring. These deficits are associated with genome-wide DNA hypomethylation and abnormal expression of cognition-related genes in the hippocampus. Arsenic atoms directly bind to the cysteine-rich ADD domain of DNA methyltransferase 3A (DNMT3A), triggering ubiquitin- and proteasome-mediated degradation of DNMT3A in different cellular contexts. DNMT3A degradation leads to genome-wide DNA hypomethylation in mouse embryonic fibroblasts but not in non-embryonic cell lines. Treatment with metformin, a first-line antidiabetic agent reported to increase DNA methylation, ameliorates the behavioral deficits and normalizes the aberrant expression of cognition-related genes and DNA methylation in the hippocampus of arsenic-exposed offspring. Our study establishes a DNA hypomethylation effect of developmental arsenic exposure and proposes a potential treatment against cognitive deficits in the offspring of pregnant women in arsenic-contaminated areas.

Arsenic Bioaccumulation and Identification of Low-Arsenic-Accumulating Food Fishes for Aquaculture in Arsenic-Contaminated Ponds and Associated Aquatic Ecosystems.

Arsenic-contaminated food including farmed fish is one of the main routes of human exposure. Fish farmed in contaminated environment accumulates arsenic in different tissues with great variability. Thus, it is utmost important to quantify the risk associated with different farmed fish species in arsenic-contaminated aquaculture systems. In the present study, arsenic content was measured in twelve fish species (Labeo rohita, L. catla, Cirrhinus mrigala, Oreochromis niloticus, O. mossambicus, Liza tade, Puntius javanicus, L. calbasu, Glossogobius giuris, Macrobrachium rosenbergii, Ctenopharyngodon idella, and Bellamya bengalensis (gastropod)) collected from arsenic-contaminated aquaculture systems. Among the studied finfishes, C. idella was found to accumulate the lowest amount of arsenic (< 0.05 ± 0.00mgkg-1) whereas the highest accumulation was noticed in O. mossambicus (1.0 ± 0.18mgkg-1). However, the estimated carcinogenic and non-carcinogenic risks of human were found to be low for all the studied fishes. The calculated target hazard quotient (THQ) value for adults ranged from 0.01 to 0.08 whereas for children it ranged from 0.05 to 0.27 for low-arsenic-accumulating fishes (arsenic conc. < 0.5mgkg-1). Based on these findings, C. mrigala, C. idella, and M. rosenbergii could be recommended as the candidate species for aquaculture in the arsenic-contaminated areas as farming of the low-arsenic-accumulating food fishes would also lower the risk of human exposure through food chain.

Determination of Arsenic Uptake Potential in An Edible Plant Species (Trigonellna foenum- granecum) and Assessment of Human Health Risk

Arsenic is a carcinogenic and toxic element that possesses a high health risk from its presence in crops, water, and soil. The present study has been conducted by fenugreek (Trigonella foenum-granecum) seeds which is a very common spice used for cooking, especially in India. An equal number of seeds have been germinated in laboratory conditions. Three concentrations e.g. 1, 2, and, 3 mg/L of arsenite (As+3) and arsenate (As+5) salt solutions were used throughout the experiments for the treatment of plants. After 10 days of germination, the concentration of the arsenic accumulated into the plant edible parts was estimated and health risk was assessed. Effects of arsenic concentration were observed through estimating the total chlorophyll (a, b, c), carotenoid content, and taking the fresh weight and dry weight of both the control and treatment plants. The results of the biochemical analysis revealed that chlorophyll and carotenoid contents were decreased than that of control plants. Moreover, fresh weight and dry weight results also showed lower values in treatments than in controls. The bioaccumulation factor results demonstrated that an increased level of soil arsenic doesn’t certainly result in high arsenic uptake by the Fenugreek plants. From the concentration estimated in the plant body, the health risk was assessed in adults and children and found that both adults and children having a potential health risk upon consumption of fenugreek. Moreover, Incremental Life Time Cancer Risk was found high (&lt; 10-4) which indicates the presence of potential cancer risk. Hence, it is possible to conclude from the present study that fenugreek can bio-accumulate arsenic and it may be used as an indicator plant for arsenic-contaminated areas.

Prenatal exposure to arsenic and lung function in children from the New Hampshire Birth Cohort Study

Prenatal arsenic exposure is associated with an increased risk of lung cancer along with multiple non-carcinogenic outcomes, including respiratory diseases in arsenic-contaminated areas. Limited epidemiologic data exist on whether in utero arsenic exposure influences lung development and subsequent respiratory health. We investigated the association between gestational arsenic exposure and childhood lung function in the New Hampshire Birth Cohort Study. Urinary arsenic speciation including inorganic arsenic (iAs), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine was measured in maternal urine samples collected during pregnancy and spirometry was performed in offspring at a median age of 7.4 years. Forced vital capacity (FVC), forced expiratory volume in the first second of exhalation (FEV1), and forced expiratory flow between 25% and 75% of FVC (FEF25-75) standardized z-scores were assessed in linear models as dependent variables with the log2-transformed summation of urinary arsenic species (ΣAs = iAs + MMA + DMA) corrected for specific gravity as an independent variable and with adjustment for maternal smoking status, children’s age, sex and height. Among the 358 children in the study, a doubling of ΣAs was associated with a −0.08 (ß) decrease in FVC z-scores (95% confidence interval (CI) from −0.14 to −0.01) and −0.10 (ß) (95% CI from −0.18 to −0.02) decrease in FEV1 z-scores. The inverse association appeared stronger among those mothers with lower secondary methylation index (urinary DMA/MMA), especially among girls. No association was observed for FEF25-75 z-scores. Our results suggest that gestation arsenic exposure at levels relevant to the general US population during the vulnerable period of lung formation may adversely affect lung function in childhood.

Deficit irrigation and organic amendments can reduce dietary arsenic risk from rice: Introducing machine learning-based prediction models from field data

Dietary rice consumption can assume a significant pathway of the carcinogenic arsenic (As) in the human system. In search of a viable mitigation strategy, a field experiment was conducted with rice (cv. IET-4786) at geogenically arsenic-contaminated areas (West Bengal, India) for two consecutive years. The research aimed to explore irrigation management (saturation and alternate wetting and drying), and organic amendments (vermicompost, farmyard manure, and mustard cake) efficiencies in reducing As load in the whole soil-plant system. A thrice replicated strip plot design was employed and As content in the soil, plant parts, and the associated soil physicochemical properties were determined through a standard protocol. Results revealed that the most negligible As accumulation in the edible grains was accomplished by vermicompost amendment along with alternate wetting and drying (0.318 mg kg−1) over farmer’s practice of continuous submergence with no manure situation (0.895 mg kg−1). Interestingly, an increase in the grain yield by 25% was also observed. The risk of dietary exposure to As through rice was assessed by target cancer risk (TCR) and severity adjusted margin of exposure (SAMOE) mediated risk thermometer. The adopted strategy made all the risk factors somewhat benign to ensure a better standard of health. The Machine Learning algorithm revealed that Random Forest performed better in predicting grain As concentration than k-Nearest Neighbour and Generalized Regression Model. Hence, if properly calibrated and validated, the former can represent an effective tool for predicting grain As concentration in rice.

Concentrations of toxic elements and health risk assessment in arum grown in arsenic-contaminated areas of Bangladesh

Arum plant parts such as stem, leaf and corm and the corresponding farm soils were sampled from four As-impacted districts of Bangladesh to assess the potential health risk to humans from toxic elements (TEs) including arsenic (As), cadmium (Cd) and lead (Pb). The mean concentrations of As in arum leaf, stem and corm were 150 μg/kg, 107 μg/kg and 101 μg/kg, respectively, whereas mean Cd in arum leaf, stem and corm were 115 μg/kg, 261 μg/kg and 180 μg/kg, respectively and mean Pb in arum leaf, stem and corm were 595 μg/kg, 403 μg/kg and 577 μg/kg, respectively. Daily dietary intake of As, Cd and Pb from sampled arum were 0.003, 0.008 and 0.021 μg/kg bw for adults. As per capita intake of arum is low, hazard quotient (HQ) values for all TEs were found minimal, which reveals no appreciable health risk associated with arum consumption to the local inhabitants.

Deep removal of arsenite from water with no need for pre-oxidation or in-line oxidation

Arsenite is toxic and labile in subsurface media. Oxidation of arsenite to arsenate is a widely used strategy to enhance the removal of arsenic from water. However, the formation of unwanted oxidation byproducts is a major concern in drinking water treatment. Herein, a titanium xerogel (TAX) was fabricated with abundant surface hydroxyl groups and anchored acetylacetone (AA) molecules that served as powerful capturing sites for arsenic. The resultant xerogel had high adsorption capacity for arsenic without the need for any pre-treatment (306 and 254 mg/g for arsenate and arsenite, respectively, at pH 7.0). Columns packed with TAX could effectively lower arsenite concentration from 200 μg/L to less than 10 μg/L for up to 6000 bed volumes, which is more than 10 times greater than those achieved by well-developed iron or zirconium-based nanocomposites. Besides the excellent arsenite capturing ability, the TAX was also effective in removing heavy metals and commonly co-existing iron and manganese species in arsenic-contaminated groundwater. Moreover, the TAX had good antibacterial activity toward Escherichia coli. These attributes make the TAX a promising point-of-use adsorbent for residents in arsenic-contaminated areas, especially areas lacking infrastructure for water treatment.