iAs Concentrations Research Articles

Influence of geological faults on dissolved arsenic concentrations in an overexploited aquifer with shallow geothermal heat

Hydrochemical and mineralogical analyses were performed to identify the main processes that contribute to the concentration of total inorganic arsenic (iAs) in groundwater within the northern portion of the Laguna Seca aquifer in Guanajuato State, Mexico. The spatial extent of the study area spans across a large graben with pore-waters that contain the highest dissolved arsenic concentrations in the basin. This scale of study was chosen to test the hypothesis that normal faults act as conduits for rising geothermal waters carrying arsenic into the shallow aquifer that has been historically depressurized by irrigation pumping. The arsenic content in outcrops ranged from 3.5 to 19.5 ppm. The major minerals are quartz, plagioclase, micas, and zeolites. Multivariate cluster and Principal Components Analyses on the chemical composition and temperature of 15 wells in the study area suggest that silicate weathering is the dominant water-rock interaction that explains the observed concentrations of major ions and arsenic in groundwater. The sampled irrigation and municipal wells ranged from 190 to 550 m in depth and had temperatures ranging from 28.3 to 45.2 °C. Cluster II had the highest temperature, and greatest mineralization (total dissolved solids), and it was more influenced by regional flow than Cluster I. The concentration of iAs ranged from 16 to 229 μgL−1, all of the samples exceeded the maximum concentration suggested by the World Health Organization (10 μgL−1). Four samples belonging to Cluster II exceeded the maximum concentration set by Mexican regulations (25 μgL−1) by at least five times. The highest concentration of arsenic in surface rock coincides spatially with Cluster II wells. Geothermal heat and long pore-water-residence times enables the dissolution of silicate minerals which increases the pH (from 7.3 to 9.1) and consequently drives desorption of arsenic from mineral surfaces. During the dry season the iAs content increased in all wells from 6 to 138 μgL−1 compared to the wet season. This could be attributed to the increase in pumping that occurs then. The close proximity of Cluster II wells to newly mapped faults within the graben supports the hypothesis that Cluster II wells intercept regional groundwater flow that ascends through those previously unmapped faults.

Arsenic species and their health risks in edible seaweeds collected along the Chinese coastline

Edible seaweeds with a relatively high total arsenic concentration have been a global concern. As the largest seaweed producer, China contributes about 60 % of the global seaweed production. The present study investigated 20 seaweed species collected from representative seaweed farming sites in the six provinces along the Chinese coastline, of which Saccharina japonica, Undaria pinnatifida, Neopyropia spp., Gracilaria spp., Sargassum fusiforme were listed as the most consumed seaweeds in Food and Agriculture Organization of the United Nations (FAO). The inorganic arsenic (iAs) concentration in most of the seaweeds was below maximum limits (0.3 mg iAs/kg) as seaweed additives for infant food in the National Food Safety Standard of Pollutants in China (GB2762-2017, 2017), except for the species Sargassum, in which the iAs concentration significantly exceeded the limit and ranged from 15.1 to 83.7 mg/kg. Arsenic speciation in 4 cultivated seaweeds grown in both temperate and subtropical zones is reported for the first time. No significant differences in total As and iAs concentration were identified, except slightly higher total As concentration were found in Saccharina japonica growing in the temperate zone. The estimated daily intake (EDI) of toxic iAs via seaweed consumption was generally below the EFSA CONTAM Panel benchmark dose lower confidence limit (0.3 μg/kg bw/day) except for all Sargassum species where the EDI was significantly higher than 0.3 μg/kg bw/day. Moreover, the first-ever reported data on As speciation indicated very high iAs concentrations in Sargassum hemiphyllum and Sargassum henslowianum. To minimize the food chain iAs exposure, reducing both human intake of Sargassum spp. and the used of Sargassum spp. for animal feed is highly recommended. CapsuleThis study showed that edible seaweed Sargassum spp. consumption may pose a health risk related to inorganic arsenic (iAs) exposure. The risk of iAs exposure via seaweed consumption or livestock is a concern that needs to be monitored. The arsenic accumulation and speciation may be predominantly species-dependent rather than environmental-dependent.

An interaction of inorganic arsenic exposure with body weight and composition on type 2 diabetes indicators in Diversity Outbred mice.

Type 2 diabetes (T2D) is a complex metabolic disorder with no cure and high morbidity. Exposure to inorganic arsenic (iAs), a ubiquitous environmental contaminant, is associated with increased T2D risk. Despite growing evidence linking iAs exposure to T2D, the factors underlying inter-individual differences in susceptibility remain unclear. This study examined the interaction between chronic iAs exposure and body composition in a cohort of 75 Diversity Outbred mice. The study design mimics that of an exposed human population where the genetic diversity of the mice provides the variation in response, in contrast to a design that includes untreated mice. Male mice were exposed to iAs in drinking water (100ppb) for 26weeks. Metabolic indicators used as diabetes surrogates included fasting blood glucose and plasma insulin (FBG, FPI), blood glucose and plasma insulin 15min after glucose challenge (BG15, PI15), homeostatic model assessment for [Formula: see text]-cell function and insulin resistance (HOMA-B, HOMA-IR), and insulinogenic index. Body composition was determined using magnetic resonance imaging, and the concentrations of iAs and its methylated metabolites were measured in liverand urine. Associations between cumulative iAs consumption and FPI, PI15, HOMA-B, and HOMA-IR manifested as significant interactions between iAs and body weight/composition. Arsenic speciation analyses in liver and urine suggest little variation in the mice's ability to metabolize iAs. The observed interactions accord with current research aiming to disentangle the effects of multiple complex factors on T2D risk, highlighting the need for further research on iAs metabolism and its consequences in genetically diverse mouse strains.

Concentrations of blood and urinary arsenic species and their characteristics in general Korean population

Arsenic (As) exposure has been extensively studied by investigating As species (e.g., inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA)) in urine, yet recent research suggests that blood could be a possible biomarker of As exposure. These investigations, however, were conducted on iAs-contaminated areas, and evidence on populations exposed to low levels of iAs is limited. This study aimed to describe the levels and distributions of As species in urine and blood, as well as to estimate methylation efficiency and related factors in the Korean population. Biological samples were obtained by the Korean Ministry of Food and Drug Safety. A total of 2025 urine samples and 598 blood samples were utilized in this study. Six As species were measured using ultra-high-performance liquid chromatography with inductively coupled plasma mass spectrometry (UPLC-ICP-MS): As(V), As(III), MMA, DMA, arsenobetaine (AsB), and arsenocholine (AsC). Multiple linear regression models were used to examine the relationship between As species (concentrations and proportions) and covariates. AsB was the most prevalent species in urine and blood. The relative composition of iAs, MMA, DMA, and AsC in urine and blood differed significantly. Consumption of blue-backed fish was linked to higher levels of AsB in urine and blood. Type of drinking water and multigrain rice consumption were associated with increased iAs concentration in urine. Except for iAs, every species had correlations in urine and blood in both univariate and multivariate analyses. Adolescents and smokers presented a lower methylation efficiency (higher %MMA and lower %DMA in urine) and females presented a higher methylation efficiency (lower %iAs, %MMA, and higher %DMA in urine). In conclusion, blood iAs concentration cannot represent urinary iAs; nonetheless, different compositions of urine and blood might reflect distinct information about iAs exposure. Further investigations on exposure factors and health are needed using low-exposure groups.

Assessing the risk of human exposure to bioaccessible arsenic from total diet through market food consumption in Chengdu, China.

To assess the daily intake of total arsenic (tAs) and arsenic speciation and their potential health risks, different food groups, including vegetables, rice, meat, viscera, freshwater fish, and seafood from Chengdu, China were analyzed. The concentrations of tAs ranged from 41.3 to 1185μgkg-1 with a median of 238μgkg-1, and 26.0% of tAs in the food groups was of inorganic toxic form. The median concentration of As(V) in rice (184 ± 21.6μgkg-1) was approximately 2 to 6 times higher than those in other food groups. The bioaccessible inorganic arsenic (iAs) concentrations of the food items obtained from the local markets of Chengdu ranged from 1.07 to 24.6μgkg-1 (mean of 6.04μgkg-1). Rice contributed toward the largest amount of daily iAs intake (66.2%). The mean daily iAs intake from vegetable, meat and viscera contributed 10.7%, 12.5% and 6.04% of total iAs intake, respectively. The actual concentration of arsenic in the food exposed to the human body depends on oral bioaccessible fraction. The oral bioaccessibility estimated daily intake (μg kg-1 bw d-1) of tAs and iAs for the residents of Chengdu was 0.32 and 0.16. Health risk assessments carried out based on bioaccessible iAs concentrations showed that the food items were safe for consumption from the iAs perspective.

Arsenic and Nutrient Composition Across Different Edible Seaweeds From Hawaii

ObjectivesSeaweed is used for various cultural, culinary, and medicinal purposes in Hawaii and has been consumed for generations around the world (i.e., the Pacific, Asia, and parts of Europe). In the US, seaweed is gaining popularity because of its reputation for being highly nutritional. However, some types of seaweed are known to accumulate heavy metals, including inorganic arsenic (iAs) species. While some seaweed species have been studied, there is still limited species-specific compositional data. The purpose of this study was to quantify arsenic and nutrient (i.e., macronutrient and mineral) levels in edible seaweeds.MethodsBrown algae (Sargassum aquifolium and Sargassum spp.), red algae (Gracilaria parvispora, Halymenia formosa, and Halymenia hawaiiana, and green algae (Ulva ohnoi) were analyzed using HPLC-ICP-MS for arsenic speciation. Proximate (protein, dietary fiber, ash, moisture, carbohydrate, crude fat, and crude protein) and mineral (P, K, Ca, Mg, Na, Fe, Mn, Zn, Cu, B) analyses were conducted. Values were expressed per freeze-dried weight (FDW) or fresh weight serving (FW) of seaweed.ResultsBrown algae had the highest concentration of total and iAs compared to all others. Statistical differences amongst macronutrients and minerals existed across seaweed species, with G. parvispora having higher Mn (∼510 µg/g FDW) and K (∼4.6 g/100g FDW) levels compared to all other samples (P < 0.05). Based on recommended nutritional daily values, G. parvispora (∼80 g FW) was high in Mn, H. formosa (∼100 g FW) was high in Fe, U. ohnoi (∼100 g FW) was high in Mg, and H. hawaiiana (∼100 g FW) was high in Mg, Fe, and Zn.ConclusionsOverall, these findings indicate significant differences in composition across seaweed species. As some seaweeds were excellent sources of essential nutrients while others were high in iAs, it is critical to continually expand compositional data to assess both nutritional adequacy and safety of diets.Funding SourcesUSDA-ARS, FDA.

Burden of Coronary Heart Disease and Cancer from Dietary Exposure to Inorganic Arsenic in Adults in China, 2016.

Background and Objectives:Inorganic arsenic (iAs) can cause a wide range of health problems, including coronary heart disease (CHD) and lung, bladder, and skin cancer. Although dietary iAs intake is the primary source of iAs, the burden of CHD and cancers from dietary iAs exposure in Chinese adults has not been well known.Methods:To estimate the iAs exposure level in Chinese adults’ diet, we systematically collected food-specific iAs concentrations in China from Chinese and English literature databases during 2000-2020. Food consumption was extracted from two nationwide food and nutrition surveys in China. The population attributable fraction was calculated based on the dose-response relationship between iAs and CHD risk. Combining the 2016 Chinese tumor registry data, we calculated the annual incidence of cancer from dietary iAs exposure to measure the disability-adjusted life year (DALY) in 2016.Findings:The total amount of daily foodborne iAs intake was 0.55 μg/kg bw/day among Chinese adults. The DALY of foodborne iAs-associated CHD was 3,017,510, which accounted for 10.18% of total CHD DALY in Chinese adults in 2016. Moreover, the carcinogenic DALY for lung cancer, bladder cancer, and skin cancer of Chinese residents in 2016 related to dietary iAs was 314.24, 9.89, and 167.32 thousand, accounting for 2.05%, 1.70%, and 35.5% of the total cancer burden, respectively.Conclusions:Our findings suggested that dietary iAs exposure causes a substantial disease burden in Chinese adults. More efforts for foodborne iAs control are critical to reducing the disease burden of CHD and cancer in China and other countries with similar dietary patterns.

Arsenic Accumulation and Biotransformation Affected by Nutrients (N and P) in Common Blooming-Forming Microcystis wesenbergii (Komárek) Komárek ex Komárek (Cyanobacteria)

Arsenic accumulation and biotransformation in algae was mostly carried out in a medium that contained far higher nutrient concentrations than that in natural freshwaters. The obtained results might have limited environmental validity and result in a failure to describe authentic arsenic biogeochemical cycles in natural freshwater systems. To validate the assumption, arsenic accumulation, and biotransformation in common bloom forming Microcystis wesenbergii was performed under a high nutrient concentration in BG11 medium (N = 250 mg/L, P = 7.13 mg/L), and adjusted low nutrients that mimicked values in natural freshwaters (N = 1.5 mg/L, P = 0.3 mg/L). The growth rate and maximum M. wesenbergii cell density were much lower in the high nutrient set, but more inhibition was shown with increasing ambient iAs(V) concentrations both in the high and low nutrient sets. The proportion of intracellular contents in total arsenicals decreased with increasing iAs(V) concentrations in both high and low nutrient sets but increased with incubation time. Intracellular iAs(III) was not found in the high nutrient set, while it formed high concentrations that could be comparable to that of an extracellular level in the low nutrient set. M. wesenbergii could methylate arsenic, and a higher proportion of organoarsenicals was formed in the low nutrient set. Lower intracellular MMA(V) and DMA(V) concentrations were found in the high nutrient set; contrarily, they presented a higher concentration that could be comparable to the extracellular ones in the low nutrient set. The results demonstrated that different nutrient regimes could affect arsenic accumulation and biotransformation in M. wesenbergii, and low nutrient concentrations could inhibit the excretion of iAs(III), MMA(V) and DMA(V) out of cells. Further investigations should be based on natural freshwater systems to obtain an authentic arsenic accumulation and biotransformation in cyanobacteria.

Influence of combined exposure levels of total arsenic and inorganic arsenic on arsenic methylation capacity among university students: findings from Bayesian kernel machine regression analysis.

The arsenic (As) methylation capacity is an important determinant of susceptibility to As-related diseases. Total As (TAs) or inorganic As (iAs) was reported to associated with As methylation capacity. We measured urinary concentrations of iAs, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) by using HPLC-HG-AFS and calculated the primary methylation capacity index (PMI) and secondary methylation capacity index (SMI) in 209 university students in Hefei, China, a non-As endemic area. Volunteers were given a standardized questionnaire asking about their sociodemographic characteristics. Bayesian kernel machine regression (BKMR) analysis was used to estimate the association of lnTAs and lniAs levels with methylation indices (ln%MMA, ln%DMA, lnPMI, lnSMI). The median concentrations of iAs, MMA, and DMA were 1.22, 0.92, and 12.17μg/L, respectively; the proportions of iAs, MMA, and DMA were 8.76%, 6.13%, and 84.84%, respectively. Females had higher %DMA and lower %MMA than males. The combined levels of lnTAs and lniAs showed a decrease in the changes in ln%DMA and lnSMI. With regard to the single exposure level, the lnTAs showed positive correlations with ln%DMA, lnPMI, and lnSMI when lniAs was set at a specific level, while lniAs showed negative correlations with ln%DMA, lnPMI, and lnSMI when lnTAs was set at a specific level; all the dose-response relationships were nonlinear. Our results suggested that combined levels of TAs and iAs play an important role in reducing As methylation capacity, especially iAs, and the reduction only occurs when TAs and iAs are present up to a certain combined level.

Combined amendment improves soil health and Brown rice quality in paddy soils moderately and highly Co-contaminated with Cd and As

In situ remediation technology applied aims to not only decrease cadmium (Cd) and arsenic (As) uptake by rice but also improve soil health and rice quality in contaminated paddy soils. Here the effects of a combined amendment, consisting of limestone, iron powder, silicon fertilizer, and calcium-magnesium-phosphate fertilizer, with three application rates (0, 450, and 900 g m−2) on soil health, rice root system, and brown rice quality were compared in moderately versus highly Cd and As co-contaminated paddy fields. After the amendment application, soil pH, cation exchange capacity, four kinds of soil enzyme activities increased (sucrase, urease, acid phosphatase, and catalase), and concentrations of leached Cd/As decreased, as measured by the DTPA (diethylene triamine pentaacetic acid) and TCLP (toxicity characteristic leaching procedure). Changes in the above soil indicators promoted soil health. In both fields, the dithionite-citrate-bicarbonate (DCB)-Fe and DCB-Mn concentration in iron plaque increased and root length became longer. Changes in the above root system indicators reduced the root system's absorption of Cd and As but increased that of nutrients. Under 900 g m−2 treatment, the Cd concentration in brown rice of two sites decreased by 55.8% and 28.9%, likewise inorganic As (iAs) decreased by 50.0% and 21.1%, whereas essential amino acids increased by 20.4% and 20.0%, respectively. Furthermore, the Cd and iAs concentrations in brown rice were <0.2 mg kg−1 (maximum contaminant level of Cd and iAs in the Chinese National Food Safety Standards GB2762-2017 for brown rice) under the 900 g m−2 in the moderately contaminated field. These results suggest the combined amendment can improve soil health and brown rice quality in the moderately and highly Cd- and As-co-contaminated paddy soils, offering potential eco-friendly and efficient remediation material for applications in such polluted paddy soils.

Essential nutrient element profiles in rice types: a risk-benefit assessment including inorganic arsenic.

Rice is consumed by nearly half of the global population and a significant source of energy and nutrients. However, rice consumption can also be a significant pathway of inorganic arsenic (iAs) exposure, thus requiring a risk-benefit assessment. This study assessed nutrient element (NE) densities in fifty-five rice types (white, brown and wild rice) marketed in the UK. Densities of essential NE were used to rank rice types in meeting daily NE targets under different consumption scenarios through a newly developed optimisation approach. Using iAs data from these rice types, we assessed the margin of exposure (MOE) for low (the UK) and high (Bangladesh) rice intake scenarios. Our results showed that brown and wild rice are significantly higher in many NE and significantly contribute to dietary reference value (DRV). Our modelling showed that switching to brown or wild rice could increase the intake of several essential nutrients by up to eight times that of white rice. Using rice consumption data for mid-to-high-consumption countries, we estimate that brown rice could provide 100 % adult DRV for Fe, Mg, Cr, P and Mo, and substantial contributions for Zn, Se and K. Our results show that the amount of rice primarily determines risk from iAs consumed rather than the type of rice. Therefore, switching from white to brown or wild rice could be beneficial, provided iAs concentration in rice is within the recommended limits.

Multi-Year Survey and Bayesian Modeling Approach for Characterizing Arsenic Pollution in Marine Clams Cultivated Along the Tidal Flats of Mid-Eastern China

Marine clam is one of the main sources of arsenic (As), and the tidal flats of Jiangsu Province are considered major culturing areas for clams in mid-eastern China. In view of increasingly severe pollution in this region, concerns have been raised by the consumers with the safety of clams they purchased or may purchase. To address these concerns, we conducted a multi-year survey to determine the levels of As and As species in five major clam species cultivated in eight production areas of this region. Based on the above analysis data, Bayesian statistics used a Markov Chain Monte Carlo approach was applied to predict the toxic As residue distributions in clams produced in this region and their health risks to Chinese adults. It was found that the bioaccumulation ability of total As (tAs) and inorganic As (iAs) was species-specific, while Mactra veneriformis (MV) had the strongest accumulation capacity for toxic iAs (0.22–2.85 mg/kg dw). Up to 6.7% of the tested MV samples exceeding the iAs limit of China Food and Drug Administration. The content of iAs was also found to be related significantly to the harvest seasons, with clam in the spawning period (June) having the lowest iAs concentrations. The non-carcinogenic and carcinogenic health risk from dietary exposure to iAs associated with MV consumption was rather high, which suggested that specific attention should be paid to the safety of clam consumption in this region.

Regional variability of arsenic content in Uruguayan polished rice

Characterization of the country internal variability of arsenic (As) accumulation in rice grain across different rice production regions is very important in order to analyze its compliance with international and regional limits. A robust sampling study scheme (n = 150 samples) was performed to determine total arsenic (tAs) and inorganic (iAs) levels from polished rice grain covering all rice producing regions along two growing seasons.The mean and median concentration of tAs were 0.178 mg kg-1 and 0.147 mg kg-1, with a minimum and maximum value of 0.015 mg kg−1 and 0.629 mg kg−1, respectively and a coefficient of variation of 63.6%. The mean and median concentration of iAs were 0.062 mg kg−1 and 0.055 mg kg−1 respectively ranging from 0.005 mg kg−1 up to a maximum of 0.195 mg kg−1 and a coefficient of variation of 51.5%. A moderate correlation was revealed within iAs and tAs. Levels of iAs in all of the samples were below the international limits of 0.2 mg kg−1 according to the international limits for human health by the Codex Alimentarius (FAO and WHO, 2019).Rice fields cultivated on soils originated from igneous geological material reported lower arsenic levels accumulated in rice grain in relation to sedimentary soils. Japonica cultivars presented significantly lower tAs and iAs concentrations than Indica ones (p = 0.0121 and p < 0.0001; respectively).Consumption of rice by male and female adults in Uruguay is safe according to its level of annual consumption and based on the mean iAs levels determined in this study.

Arsenic speciation in rice bran: Agronomic practices, postharvest fermentation, and human health risk assessment across the lifespan

Arsenic (As) exposure is a global public health concern affecting millions worldwide and stems from drinking water and foods containing As. Here, we assessed how agronomic practices and postharvest fermentation techniques influence As concentrations in rice bran, and calculated health risks from consumption. A global suite of 53 rice brans were tested for total As and speciation. Targeted quantification of inorganic As (iAs) concentrations in rice bran were used to calculate Target Hazard Quotient (THQ) and Lifetime Cancer Risk (LCR) across the lifespan. Mean iAs was highest in Thailand rice bran samples (0.619 mg kg−1) and lowest in Guatemala (0.017 mg kg−1) rice bran samples. When comparing monosodium-methanearsonate (MSMA) treated and the Native-soil counterpart under the irrigation technique Alternate Wetting and Drying (AWD) management, the MSMA treatment had significantly higher total As (p = 0.022), and iAs (p = 0.016). No significant differences in As concentrations were found between conventional and organic production, nor between fermented and non-fermented rice bran. Health risk assessment calculations for the highest iAs-rice bran dosage scenario for adults, children and infants exceeded THQ and LCR thresholds, and LCR was above threshold for median iAs-rice bran. This environmental exposure investigation into rice bran provides novel information with food safety guidance for an emerging global ingredient.

Influence of phosphorus on the uptake and biotransformation of arsenic in Porphyra haitanensis at environmental relevant concentrations

Edible seaweeds are rich in essential vitamins and minerals, which made them a popular food worldwide. Porphyra haitanensis is one of the most commonly consumed seaweeds with the known ability to accumulate a high level of total arsenic (As). A large number of articles have shown arsenic and phosphorus (P) interactions in microalgae due to the plant's inability to differentiate arsenate from phosphate. However, very limited information is available for edible seaweed at environmentally relevant concentrations. In this study, P. haitanensis was treated with arsenic as AsV (As1: 0.06 μM, As2: 0.4 μM, As3: 1.2 μM) and phosphorous (P1: 3.2 μM, P2: 13 μM) in a filtered seawater matrix under laboratory condition for six days. A better growth rate was found in seaweeds grown in P2 treatments. Moreover, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content measurements revealed that a higher P concentration prevent seaweeds from lipid peroxidation and oxidative stress. Transcriptome studies indicated the As replacement to P has the ability to target seaweed cell membrane composition, transmembrane transport, DNA and ATP binding. The inorganic As (iAs) had a concentration of 0.54 to 4.45 mg/kg in P. haitanensis on Day 6 with As1, As2, and As3 treatments under low P regime (P1), which exceeds the limits of iAs concentration (0.1–0.5 mg/kg) in National Food Safety Standard-Limits of Pollutants in Food (GB 2762-2017). High P regime (P2) not only reduced the total As but also iAs effectively, even in the highest As treatment (As3), the iAs concentration was less than 0.5 mg/kg on Day 6. These findings provide a good insight for seafood safety guarantees and are important for the management of coastal artificial seaweed farming.

Curcumin sensitizes Epstein-Barr-immortalized lymphoblastoid cell lines to inorganic arsenic toxicity.

Chronic exposure to inorganic arsenic (iAs) through contaminated drinking water is an important health problem in certain countries. The use of phytochemicals such as curcumin has recently emerged as an alternative strategy for preventing cellular damage caused by iAs. The Epstein-Barr virus (EBV) affects ~90% of the population and experimental evidence suggested that curcumin mediates cytotoxicity against EBV-infected cells. Due to the potential for an interaction of these factors, the aim of the present study was to evaluate the effect of this phytochemical on iAs-related toxicity in EBV-infected cells. Two independent EBV-immortalized human lymphoblastoid cell lines (LCLs) were used as the model. The cell lines were first incubated with increasing concentrations of curcumin or iAs for 24 and 15 h, respectively, to determine the individual effects of each exposure on cell death. In the next experiment, cell cultures were pre-incubated with 5 µM curcumin for 9 h prior to treatment with 10 µM iAs for 15 h, followed by evaluation of cell death and the cell cycle profile via flow cytometry. The results indicated that individual treatment with either curcumin or iAs induced cell death in a concentration-dependent manner. Furthermore, curcumin pre-treatment enhanced iAs-induced cell death and promoted cell cycle arrest in G1 phase. Taken together, these results suggested that curcumin sensitizes EBV-positive LCLs to the cytotoxic effects of iAs.

Dietary exposure to potentially toxic elements through sushi consumption in Catalonia, Spain

Although sushi is considered as a healthy food, it can also be a route of exposure to chemical contaminants such as potentially toxic trace elements. In this study, we analysed the concentration of Cd, I, Ni, Pb and total Hg, as well as iAs and MeHg in sushi samples. Iodine levels were higher in samples containing seaweed, while iAs concentrations were greater in rice-containing sushi. In turn, total Hg and MeHg were significantly higher in sushi samples with tuna. Health risks of sushi consumption were assessed for three population groups: children, adolescents and adults. Considering an average intake of 8 sushi pieces for adults and adolescents, and 3 sushi pieces for children, the estimated exposure to MeHg by adolescents exceeded the tolerable daily intake set by EFSA, while MeHg intake by children and adults was below, but close to that threshold. A relatively high daily exposure of Ni and Pb was also found, especially for adolescents. Since this study focused only on the consumption of sushi, the contribution of other food groups to the overall dietary exposure should not be disregarded. It might lead to an exposure to MeHg and other trace elements above the health-based guideline values.

Monomethylated arsenic was the Major methylated arsenic in Red blood cells of acute promyelocytic leukemia patients treated with arsenic trioxide

BackgroundArsenic trioxide (ATO) has been successfully applied in the treatment of acute promyelocytic leukemia (APL). Arsenic metabolites including inorganic arsenic and methylated arsenic could lead to different toxicity and curative effect. This study aims to establish a method to determine arsenic species in red blood cells (RBCs), clarify the distribution characteristics of arsenic species in RBCs. MethodsSteady state blood samples were collected from 97 APL patients. H2O2 and HClO4 were used to release the hemoglobin bounding arsenic and precipitate protein. Arsenite (iAsIII), arsenate (iAsV), monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) in plasma and RBCs were detected by HPLC-HG-AFS. Free and bound arsenic species in RBCs were separated by 30 kDa molecular mass cutoff filters and determined to evaluate hemoglobin binding capacity of different arsenic species. ResultsThe method was validated with accuracy ranged from 84.75% to 104.13%. Arsenic species in RBCs followed the trend iAs > MMA > DMA (p < 0.01), while the concentration of DMA was significantly higher than iAs and MMA in plasma (p < 0.01). The correlation between iAs concentration in plasma and corresponding RBCs arsenic level was weak. And the concentrations of DMA and MMA in plasma were moderately positive correlated with those in RBCs. Hemoglobin-binding ratios of iAs, MMA and DMA were all over 70 %. ConclusionsIn this study, we provided a reliable method to determine arsenic species in RBCs of APL patients treated with ATO by HPLC-HG-AFS. It was confirmed that the concentration of DMA is the highest in plasma, while MMA is the most predominant methylated arsenic in RBCs. High affinity of MMA with human Hb was responsible for the accumulation of arsenic in RBCs of APL patients.

Association of arsenic-induced cardiovascular disease susceptibility with genetic polymorphisms

Inorganic arsenic (iAs) exposure has been reported to have an impact on cardiovascular diseases (CVD). However, there is not much known about the cardiac tissue injury of CVD patients in relation to iAs exposure and potential role of single nucleotide polymorphisms (SNPs) of genes related to iAs metabolism, oxidative stress, endothelial dysfunction and inflammation which may play important roles in such CVD cases. In this dual center cross-sectional study, based on the exclusion and inclusion criteria, we have recruited 50 patients out of 270, who came from known arsenic-affected and- unaffected areas of mainly Chittagong, Dhaka and Rajshahi divisions of Bangladesh and underwent open-heart surgery at the selected centers during July 2017 to June 2018. We found that the patients from arsenic affected areas contained significantly higher average iAs concentrations in their urine (6.72 ± 0.54 ppb, P = 0.028), nail (529.29 ± 38.76 ppb, P < 0.05) and cardiac tissue (4.83 ± 0.50 ppb, P < 0.05) samples. Patients’ age, sex, BMI, hypertension and diabetes status adjusted analysis showed that patients from arsenic-affected areas had significantly higher iAs concentration in cardiac tissue (2.854, 95%CI 1.017–8.012, P = 0.046) reflecting higher cardiac tissue injury among them (1.831, 95%CI 1.032–3.249, P = 0.039), which in turn allowed the analysis to assume that the iAs exposure have played a vital role in patients’ disease condition. Adjusted analysis showed significant association between urinary iAs concentration with AA (P = 0.012) and AG (P = 0.034) genotypes and cardiac iAs concentration with AA (P = 0.017) genotype of AS3MT rs10748835. The AG genotype of AS3MT rs10748835 (13.333 95%CI 1.280–138.845, P = 0.013), AA genotype of NOS3 rs3918181 (25.333 95%CI 2.065–310.757, P = 0.002), GG genotype of ICAM1 rs281432 (12.000 95%CI 1.325–108.674, P = 0.010) and AA genotype of SOD2 rs2758331 (13.333 95%CI 1.280–138.845, P = 0.013) were found significantly associated with CVD patients from arsenic-affected areas. Again, adjusted analysis showed significant association of AA genotype of AS3MT rs10748835 with CVD patients from arsenic affected areas. In comparison to the reference genotypes of the selected SNPs, AA of AS3MT 10748835, AG of NOS3 rs3918181 and AC of rs3918188, GG of ICAM1 rs281432, TT of VCAM1 rs3176867, AA of SOD2 rs2758331 and GT of APOE rs405509 significantly increased odds of cardiac tissue injury of CVD patients from arsenic affected areas. The results showed that the selected SNPs played a susceptibility role towards cardiac tissue iAs concentration and injury among CVD patients from iAs affected areas.

Bayesian benchmark dose analysis for inorganic arsenic in drinking water associated with bladder and lung cancer using epidemiological data

Abundant epidemiological evidence has shown that there is a strong causal relationship between long-term exposure to inorganic arsenic (iAs) through drinking water and a few types of cancer (e.g., lung and bladder cancer). Traditionally, a linear low-dose extrapolation assumption was applied in risk assessment for iAs which resulted in a relatively conservative cancer risk estimate. Growing biological evidence suggests that the mode of action of iAs-induced cancer follows a threshold process (e.g., sufficient concentration of trivalent arsenic is required to disrupt normal cellular function). In this study, we applied the benchmark dose (BMD) methodology to model the relationship between the relative risk of bladder and lung cancer and the iAs concentration in drinking water using the high-quality epidemiological data reported in recently published papers, with a special focus on the low exposure range (i.e., <150 μg/L). Because of its biological plausibility and statistical flexibility, the Hill model has been chosen to model the data under a Bayesian framework. A Bayesian hierarchal model together with a bootstrap method for exposure estimation were applied to quantify uncertainty from various sources, including the within-study, between-study, and exposure uncertainties. Dose-response assessment results obtained from a number of alternative model structures and methods consistently demonstrate a threshold type dose-response curve with a threshold in the range between 40–60 μg/L of iAs concentration in drinking water. The BMD for iAs in drinking water associated with 0.1 % increase in relative risk of bladder cancer is 42.2 μg/L (BMDL 39.2 μg/L); for 0.05 % increase, the BMD is 41.6 μg/L (BMDL 38.6 μg/L). For lung cancer, the two counterpart BMD estimates are 57.0 μg/L (BMDL 43.6 μg/L) and 55.7 μg/L (BMDL 42.5 μg/L) for 0.1 % and 0.05 % increase, respectively. These analyses provide additional statistical support for a non-linear dose response for cancer risk from inorganic arsenic which may have important policy implications.