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The toxicity of arsenic has challenged life for billions of years, but the timing of when complex organisms first evolved strategies to cope with this threat remains elusive. Here, we study 2.1-billion-year-old (Ga) Francevillian macrofossils, some of Earth’s earliest complex life forms, to establish their biogenicity and to ascertain how they managed arsenic toxicity. The studied specimens thrived in low-arsenic marine waters, yet displayed strikingly high levels of arsenic, which was actively sequestered in specialized compartments in their bodies to mitigate toxicity. Upon their death, arsenic was released and incorporated into pyrite nuclei. The patterns observed in the fossils are distinct from abiotic concretions but similar to some seen in later eumetazoans, reinforcing their biological affinity. Our findings highlight that early complex life faced significant arsenic stress, even in low-concentration marine environments, which prompted the development of essential survival mechanisms. Arsenic incorporation into pyrite nuclei reveals that the 2.1-billion-year-old Francevillian biota actively detoxified arsenic by sequestration in specialized body compartments.

Groundwater arsenic contamination has been a health hazard for West Bengal, India. Oxidative stress to DNA is recognized as an underlying mechanism of arsenic carcinogenicity. A phytochemical, curcumin, from turmeric appears to be potent antioxidant and antimutagenic agent. DNA damage prevention with curcumin could be an effective strategy to combat arsenic toxicity. This field trial in Chakdah block of West Bengal evaluated the role of curcumin against the genotoxic effects of arsenic. DNA damage in human lymphocytes was assessed by comet assay and fluorescence-activated DNA unwinding assay. Curcumin was analyzed in blood by high performance liquid chromatography (HPLC). Arsenic induced oxidative stress and elucidation of the antagonistic role of curcumin was done by observation on reactive oxygen species (ROS) generation, lipid peroxidation and protein carbonyl. Antioxidant enzymes like catalase, superoxide dismutase, glutathione reductase, glutathioneS-transferase, glutathione peroxidase and non-enzymatic glutathione were also analyzed. The blood samples of the endemic regions showed severe DNA damage with increased levels of ROS and lipid peroxidation. The antioxidants were found with depleted activity. Three months curcumin intervention reduced the DNA damage, retarded ROS generation and lipid peroxidation and raised the level of antioxidant activity. Thus curcumin may have some protective role against the DNA damage caused by arsenic.

Background The objective of this study was to evaluate the behavioral determinants associated with exclusive use of arsenic-safe water in the community-led Strong Heart Water Study (SHWS) arsenic mitigation program. Methods The SHWS is a randomized controlled trial of a community-led arsenic mitigation program designed to reduce arsenic exposure among private well users in American Indian Great Plains communities. All households received point-of-use (POU) arsenic filters installed at baseline and were followed for 2 years. Behavioral determinants selected were those targeted during the development of the SHWS program, and were assessed at baseline and follow-up. Results Among participants, exclusive use of arsenic-safe water for drinking and cooking at follow-up was associated with higher self-efficacy for accessing local resources to learn about arsenic (OR: 5.19, 95% CI: 1.48–18.21) and higher self-efficacy to resolve challenges related to arsenic in water using local resources (OR: 3.11, 95% CI: 1.11–8.71). Higher commitment to use the POU arsenic filter faucet at baseline was also a significant predictor of exclusive arsenic-safe water use for drinking (OR: 32.57, 95% CI: 1.42–746.70) and cooking (OR: 15.90, 95% CI: 1.33–189.52) at follow-up. From baseline to follow-up, the SHWS program significantly increased perceived vulnerability to arsenic exposure, self-efficacy, descriptive norms, and injunctive norms. Changing one’s arsenic filter cartridge after installation was associated with higher self-efficacy to obtain arsenic-safe water for drinking (OR: 6.22, 95% CI: 1.33–29.07) and cooking (OR: 10.65, 95% CI: 2.48–45.68) and higher perceived vulnerability of personal health effects (OR: 7.79, 95% CI: 1.17–51.98) from drinking arsenic-unsafe water. Conclusions The community-led SHWS program conducted a theory-driven approach for intervention development and evaluation that allowed for behavioral determinants to be identified that were associated with the use of arsenic safe water and changing one’s arsenic filter cartridge. These results demonstrate that theory-driven, context-specific formative research can influence behavior change interventions to reduce water arsenic exposure. The SHWS can serve as a model for the design of theory-driven intervention approaches that engage communities to reduce arsenic exposure. Trial registration The SHWS is registered with ClinicalTrials.gov (Identifier: NCT03725592).

Acid extraction is commonly used to analyze arsenic species in rice. During the extraction process, spiked monomethylarsonic acid (MMA) is often transformed into different compounds. A similar phenomenon is observed in the arsenic speciation analysis of seafood. To identify these compounds, we analyzed a previously prepared extract using liquid chromatography–time-of-flight/mass spectrometry in differential analysis and liquid chromatography–inductively coupled plasma-MS. The compound was identified as monomethylmonothioarsonic acid (MMMTA), a thioarsenical, which is estimated to be more cytotoxic than MMA. As MMMTA was readily produced by bubbling hydrogen sulfide through MMA, this suggests that MMA reacts with sulfur in rice during the extraction process. Our data also suggested that dimethylarsinic acid could be transformed into another compound, although the generation rate was low. For reliable arsenic speciation analyses, the transformation of arsenic compounds during extraction must be avoided. This study demonstrates that arsenic compounds can be transformed by dilute acid extraction.

Safe potable water is essential for good health. Worldwide, school-aged children especially in the developing countries are suffering from various water-borne diseases. In the study, drinking water supplies for primary school children were monitored at Magura district, Bangladesh, to ensure safe potable water. APHA standard analytical methods were applied for determining the physicochemical parameters of the water samples. For determination of the essential physicochemical parameters, the samples were collected from 20 randomly selected tube wells of primary schools at Magura. The metal contents, especially arsenic (As), iron (Fe), and manganese (Mn), in the water samples were analyzed by atomic absorption spectroscopy. The range of physicochemical parameters found in water samples were as follows: pH 7.05–9.03, electrical conductivity 400–2340 μS/cm, chloride 10–640 mg/L, hardness 200–535 mg/L as CaCO 3 , and total dissolved solids 208–1216 mg/L. The level of metals in the tube well water samples were as follows: As 1 to 55 μg/L, Fe 40 to 9890 μg/L, and Mn 10 to 370 μg/L. Drinking water parameters of Magura district did not meet the requirement of the World Health Organization drinking water quality guideline, or the Drinking Water Quality Standards of Bangladesh.

Environmental contamination with arsenic (As) is a global environmental, agricultural and health issue due to the highly toxic and carcinogenic nature of As. Exposure of plants to As, even at very low concentration, can cause many morphological, physiological, and biochemical changes. The recent research on As in the soil-plant system indicates that As toxicity to plants varies with its speciation in plants (e.g., arsenite, As(III); arsenate, As(V)), with the type of plant species, and with other soil factors controlling As accumulation in plants. Various plant species have different mechanisms of As(III) or As(V) uptake, toxicity, and detoxification. This review briefly describes the sources and global extent of As contamination and As speciation in soil. We discuss different mechanisms responsible for As(III) and As(V) uptake, toxicity, and detoxification in plants, at physiological, biochemical, and molecular levels. This review highlights the importance of the As-induced generation of reactive oxygen species (ROS), as well as their damaging impacts on plants at biochemical, genetic, and molecular levels. The role of different enzymatic (superoxide dismutase, catalase, glutathione reductase, and ascorbate peroxidase) and non-enzymatic (salicylic acid, proline, phytochelatins, glutathione, nitric oxide, and phosphorous) substances under As(III/V) stress have been delineated via conceptual models showing As translocation and toxicity pathways in plant species. Significantly, this review addresses the current, albeit partially understood, emerging aspects on (i) As-induced physiological, biochemical, and genotoxic mechanisms and responses in plants and (ii) the roles of different molecules in modulation of As-induced toxicities in plants. We also provide insight on some important research gaps that need to be filled to advance our scientific understanding in this area of research on As in soil-plant systems.

Over the past few decades, groundwater wells installed in rural areas throughout the major river basins draining the Himalayas have become the main source of drinking water for tens of millions of people. Groundwater in this region is much less likely to contain microbial pathogens than surface water but often contains hazardous amounts of arsenic--a known carcinogen. Arsenic enters groundwater naturally from rocks and sediment by coupled biogeochemical and hydrologic processes, some of which are presently affected by human activity. Mitigation of the resulting health crisis in South and Southeast Asia requires an understanding of the transport of arsenic and key reactants such as organic carbon that could trigger release in zones with presently low groundwater arsenic levels.

Concerns for arsenic exposure are not limited to toxic waste sites and massive poisoning events. Chronic exposure continues to be a major public health problem worldwide, affecting hundreds of millions of persons. We reviewed recent information on worldwide concerns for arsenic exposures and public health to heighten awareness of the current scope of arsenic exposure and health outcomes and the importance of reducing exposure, particularly during pregnancy and early life. We synthesized the large body of current research pertaining to arsenic exposure and health outcomes with an emphasis on recent publications. Locations of high arsenic exposure via drinking water span from Bangladesh, Chile, and Taiwan to the United States. The U.S. Environmental Protection Agency maximum contaminant level (MCL) in drinking water is 10 µg/L; however, concentrations of > 3,000 µg/L have been found in wells in the United States. In addition, exposure through diet is of growing concern. Knowledge of the scope of arsenic-associated health effects has broadened; arsenic leaves essentially no bodily system untouched. Arsenic is a known carcinogen associated with skin, lung, bladder, kidney, and liver cancer. Dermatological, developmental, neurological, respiratory, cardiovascular, immunological, and endocrine effects are also evident. Most remarkably, early-life exposure may be related to increased risks for several types of cancer and other diseases during adulthood. These data call for heightened awareness of arsenic-related pathologies in broader contexts than previously perceived. Testing foods and drinking water for arsenic, including individual private wells, should be a top priority to reduce exposure, particularly for pregnant women and children, given the potential for life-long effects of developmental exposure.

Arsenic is a toxic pollutant commonly found in the environment. Most of the previous studies on arsenic pollution have primarily focused on arsenic contamination in groundwater. In this study, we examine the impact on human health from atmospheric arsenic on the global scale. We first develop an improved global atmospheric arsenic emission inventory and connect it to a global model (Goddard Earth Observing System [GEOS]-Chem). Model evaluation using observational data from a variety of sources shows the model successfully reproduces the spatial distribution of atmospheric arsenic around the world. We found that for 2005, the highest airborne arsenic concentrations were found over Chile and eastern China, with mean values of 8.34 and 5.63 ng/m³, respectively. By 2015, the average atmospheric arsenic concentration in India (4.57 ng/m³) surpassed that in eastern China (4.38 ng/m³) due to the fast increase in coal burning in India. Our calculation shows that China has the largest population affected by cancer risk due to atmospheric arsenic inhalation in 2005, which is again surpassed by India in 2015. Based on potential exceedance of health-based limits, we find that the combined effect by including both atmospheric and groundwater arsenic may significantly enhance the risks, due to carcinogenic and noncarcinogenic effects. Therefore, this study clearly implies the necessity in accounting for both atmospheric and groundwater arsenic in future management.

Arsenic is a well-known element because of its toxicity. Humans as well as plants and animals are negatively affected by its exposure. Some countries suffer from high levels of arsenic in their tap water and soils, which is considered a primary arsenic-linked risk factor for living beings. Humans generally get exposed to arsenic by contaminated drinking waters, resulting in many health problems, ranging from cancer to skin diseases. On the other hand, the FDA-certified drug arsenic trioxide provides solutions for various diseases, including several types of cancers. This issue emphasizes the importance of speciation of the metalloid elements in terms of impacts on health. When species get exposed to arsenic, it affects the cells altering their involvement. It can lead to abnormalities in inflammatory mechanisms and the immune system which contribute to the negative impacts generated on the body. The poisoning originating from arsenic gives rise to various biological signs on the body which can be useful for the diagnosis. It is important to find true biomarkers for the detection of arsenic poisoning. In view of its application in medicine and biology, studies on understanding the biological activity of arsenic have increased. In this review, we aim at summarizing the current state of knowledge of arsenic and the mechanism behind its toxicity including genotoxicity, oxidative insults, epigenomic changes, and alterations in cellular signaling.