High Concentrations Of Arsenic Research Articles

Isolation and Identification of Arsenic-Resistant Extremophilic Bacteria from the Crater-Lake Volcano "El Chichon", Mexico.

The crater lake at "El Chichón" volcano is an extreme acid-thermal environment with high concentrations of heavy metals. In this study, two bacterial strains with the ability to resist high concentrations of arsenic (As) were isolated from water samples from the crater lake. Staphylococcus ARSC1-P and Stenotrophomonas ARSC2-V isolates were identified by use of the 16S rDNA gene. Staphylococcus ARSC1-P was able to grow in 400mM of arsenate [As(V)] under oxic and anoxic conditions. The IC50 values were 36 and 382mM for oxic and anoxic conditions, respectively. For its part, Stenotrophomonas ARSC2-V showed IC50 values of 110mM and 2.15 for As(V) and arsenite [As(III)], respectively. Arsenic accumulated intracellularly in both species [11-25nmol As × mg cellular prot-1 in cells cultured in 50mM As(V)]. The present study shows evidence of microbes that can potentially be a resource for the bio-treatment of arsenic in contaminated sites, which highlights the importance of the "El Chichón" volcano as a source of bacterial strains that are adaptable to extreme conditions.

The impact of human activities on the mangrove forests of the Qeshm Island, Iran

This article investigates the human impact on the mangrove forest in the Qeshm Geopark on the Qeshm Island in the south of Iran from 1986 to 2020. The area of mangrove forests increased by 14% from 5,131 hectares in 1986 to 5,472 hectares in 2000, and to 5,967 hectares in 2020. The mangrove forest is threatened by oil and gas facilities and a zinc smelter located on the island. The average concentration of nickel in sediment (97.2 μg/g) and in leaves (3.1 μg/g) was higher than the average concentration of vanadium in sediment (38.7 μg/g) and in leaves (0.5 μg/g). The results showed that the transfer coefficient of nickel and vanadium from root to leaf on the dry side of the Qeshm habitat (r = 0.597 and r = 0.516, respectively) was positively correlated with pH. Therefore, increasing the pH leads to an increased metal transfer from the root to the leaf, which endangers the mangrove habitat on the island. The mangrove forest in the vicinity of the zinc factory is threatened by high concentrations of lead (244.2 ppm), zinc (3172.8 ppm), arsenic, and cadmium found in the soil sample.

Inorganic arsenic in holopelagic Sargassum spp. stranded in the Mexican Caribbean: Seasonal variations and comparison with international regulations and guidelines

Due to the massive proliferation and stranding of holopelagic Sargassum spp. over the last decade, different strategies for the sustainable valorisation of Sargassum biomass have been explored and investigated. One limitation to the development of Sargassum biomass valorisation is related to its high arsenic (As) content. The toxicity of As depends on the chemical forms present and their oxidation or valence state, classified as inorganic and organic compounds, with the inorganic As compounds being much more toxic than the organic ones. The aim of the present study was to determine the inorganic arsenic (iAs) content in holopelagic Sargassum spp. for which almost no information on stranded biomass is available. In this study, we examined the iAs content in the three holopelagic Sargassum morphotypes collected over a seasonal cycle in 2018–2019. The iAs concentrations ranged from 12.7 to 62.9 mg kg−1, representing 14.1–81.7% of total arsenic (TotAs). The iAs content was compared between species and seasons and discussed in the context of existing international regulations and guidelines.

Oxidation of Trivalent Arsenic to Pentavalent Arsenic by Means of a BDD Electrode and Subsequent Precipitation as Scorodite

In order to deposit arsenic residues from copper production in a stable way, the trivalent arsenic must first be xidized to arsenic(V). A well-known but quite expensive method for this is oxidation with hydrogen peroxide. In order to enable the oxidation of arsenic on a large scale in the future, a potentially cheaper method has to be found, which offers the possibility of oxidizing extremely high arsenic concentrations. As a novel alternative, electrochemical oxidation using a boron-doped diamond electrode is investigated. Based on previous work, this paper concentrates on the presence of interfering ions during oxidation. Furthermore, it is shown that the electrochemically xidized arsenic(V) can be precipitated as scorodite. Finally, an economic analysis shows the potential financial benefit of oxidation via BDD electrodes compared to hydrogen peroxide.

Piriformospora indica alter root-associated microbiome structure to enhance Artemisia annua L. tolerance to arsenic

Microorganisms in the rhizosphere are crucial allies for plant stress tolerance. Recent research suggests that by interacting with the rhizosphere microbiome, microorganisms can aid in the revegetation of soils contaminated with heavy metal(loid)s (HMs). However, it is unknown that how Piriformospora indica influences the rhizosphere microbiome to mitigate arsenic-toxicity in arsenic-enriched environments. Artemisia annua plants were grown in the presence or absence of P. indica and spiked with low (50) and high (150 µmol/L) concentrations of arsenic (As). After inoculation with P. indica, fresh weight increased by 37.7% and 10% in control and high concentration treated plants, respectively. Transmission electron microscopy showed that cellular organelles were severely damaged by As and even disappeared under high concentration. Furthermore, As was mostly accumulated by 5.9 and 18.1 mg/kg dry weight in the roots of inoculated plants treated with low and high concentrations of As, respectively. Additionally, 16 S and ITS rRNA gene sequencing were applied to analyze the rhizosphere microbial community structure of A. annua under different treatments. A significant difference was observed in microbial community structure under different treatments as revealed by non-metric multidimensional scaling ordination. The bacterial and fungal richness and diversity in the rhizosphere of inoculated plants were actively balanced and regulated by P. indica co-cultivation. Lysobacter and Steroidobacter were found to be the As-resistant bacterial genera. We conclude that P. indica inoculation could alter rhizosphere microecology, thereby mitigating As-toxicity without harming the environment.

On the question of the mechanism of the general toxic action of lead nitrate

The leading unfavorable factor in the working environment that affects the health of miners is polymetallic dust, which contains a large number of toxic chemical elements. The study of the chemical composition of the floating dust in the air environment of the quarries of the East Kazakhstan copper-chemical plant and processing plant (Mamyrbaev, Konakbaev, 1992) showed a high content of lead, selenium, antimony, arsenic, and other trace elements.

Rapid method of arsenic estimation in geological samples by WD-XRF using a novel concept of As-Pb concentration equivalence.

The presence of arsenic in ground waters of many countries has been a subject of global concern due to its toxicity. Primary sources of arsenic are geogenic, i.e. weathering and erosion of rocks and soils containing arsenic. This paper presents a rapid method for determination of arsenic in solid geological samples by wavelength dispersive X-ray fluorescence spectrometer. To achieve the best LLD (lower limit of detection), the most intense X-ray fluorescence line Kα1,2 is preferably used for determination of elemental concentrations because it pertains to the most probable transition. But the greatest challenge in arsenic estimation is the serious line overlap of AsKα1,2 lines with the equi-energy PbLα1,2 lines. By using the conventional line overlap correction methods, uncertainty and detection limits in arsenic determination are degraded to an unacceptable degree in samples which contains high lead and low arsenic concentrations. The proposed method bypassesthe line overlap issue in employing a novel concept of arsenic-lead concentration equivalence factor for the cumulative peak of AsKα1,2 and PbLα1,2 fluorescence lines. The constancy of this factor for all geological matrices facilitates arsenic determination in samples universally irrespective of matrix elements. For the method validation, 22 international certified reference materials have been analysed and the results proved to be propitious wherein only one value out of 22 determinations showed relative error more than 20% of the certified values. This attests to the high accuracy of the proposed method which can effectively determine arsenic below 5mg/kg in the presence of high lead concentration up to 1000mg/kg.

ამბროლაურის მუნიციპალიტეტის ნიადაგების დარიშხანით დაბინძურების შესწავლა

In 2022, the level of arsenic contamination of soils as a result of exposure to hazardous industrial waste containing arsenic from Rachi Mining Chemical Plant was studied in Ambrolauri municipality. In particular, a study of arsenic contamination of the soils of the villages of Uravi, Abari, Likheti and Sori, Oni, Utsera, Shovi, Nikortsminda, Ambrolauri and Shaori reservoir was conducted. Soil samples were taken from the exposure sites of arsenic factories (Uravi 1 and Uravi 2); from agricultural fields (Sori, Abari, Likheti); From recreational (Ambrolauri, Nikortsminda, coast of Shaori reservoir) and background (Utsera, Shovi, Oni) places. Soil samples were taken at 0-5 and 5-20 cm depth in June and October. Points highly contaminated with arsenic in the soil have been identified and hazard indices have been calculated. 19 at-risk soil sampling sites were identified with hazard index (HQs>1) due to high arsenic concentrations. According to the comparison of the results of the conducted research, the soils of Uravi are the most contaminated with arsenic

Temporal groundwater quality, health risks and source point management zonation of multi-aquifers in Jilin Qian'an, Northeastern China.

Jilin Qian'an, located in Northeastern China's Songnen Plain, relies almost exclusively on groundwater for drinking. The quaternary phreatic aquifer (Q3) is distinguished by high geogenic fluoride and arsenic concentrations, which necessitates reliance on quaternary confined (Q1) and neogene confined (N) aquifers (deeper aquifers) as source point management (SPM) alternatives. However, deeper aquifers are contaminated, necessitating temporal monitoring and unique management strategies. Using 165 samples, this study investigated the appropriateness of deeper restricted aquifers as a continuous SPM alternative by assessing the spatiotemporal groundwater quality and human health risk of the multi-aquifers in Jilin Qian'an from the 1980s to the 2010s. In addition, a source point management zonation (SPMZ) was implemented to define the specific intervention necessary in various portions of the study area. Results indicate water quality parameters were within recommended limits for most samples except fluoride, while arsenic was the most significant heavy metal pollutant. Mean groundwater mineralization in all the aquifers increased with time. Deeper aquifers are still a better alternative to the shallow phreatic aquifer as groundwater quality in the study is of the order N > Q1 > Q3 in the respective aquifers. Cancer risk assessment (CR) shows increases from 2001 to the 2010s in all aquifers except in Q3. SPMZ delineated: High As and high F zones; high As and low F zones; high As zones; high F zones; low F zones; and safe zones. Localized intervention based on SPMZ is recommended, along with the use of alternative water sources.

GIS based hotspot analysis and health risk assessment of groundwater arsenic from an unconfined deep aquifer of Lahore, Pakistan.

Use of groundwater for drinking purpose poses serious hazards of arsenic contamination particularly in plains of western Himalayan region. Therefore, current study was designed to investigate the level of Arsenic (As) in the water obtained from tubewells in a metropolitan city of Lahore, Pakistan and assess the human health risk. So, a total of 73 tubewells were sampled randomly in the manner that the whole study region was covered without any clustering. The water samples were analyzed for As using atomic absorption spectrophotometer. These samples were also tested for total dissolved solids, chlorides, pH, alkalinity, turbidity, hardness and calcium. GIS based hotspots analysis technique was used to investigate the spatial distribution patterns. Our results revealed that only one sample out of total 73 had arsenic level below the WHO guideline of 10μg/L. The spatial distribution map of arsenic revealed that the higher concentrations of arsenic are present in the north-western region of Lahore. The cluster and outlier analysis map using Anselin Local Moran's I statistic indicated the presence of an arsenic cluster in the west of River Ravi. Furthermore, the optimized hotspot analysis based on Getis-Ord Gi* statistics confirmed the statistical significance (P < 0.05) and (P < 0.01) of these samples from the vicinity of River Ravi. Regression analysis showed that variables such as turbidity, alkalinity, hardness, chlorides, calcium and total dissolved solids were significantly (all P < 0.05) associated with level of Arsenic in tubewells. Whereas, PH and electrical conductivity and other variables like town, year of installation, depth and diameter of the wells were not significantly associated with Arsenic concentrations in tubewells. Principal component analysis (PCA) exhibited that the random distribution of tubewell samples showed no distinct clustering with towns studied. Health risk assessment based on hazard and Cancer risk index revealed serious risk of developing carcinogenic and non-carcinogenic diseases particularly in children. The health risk due to prevalence of high As concentration in tubewells' water need to be mitigated immediately to avoid worst consequences in future.

Neurocognitive Analysis of Low-level Arsenic Exposure and Executive Function Mediated by Brain Anomalies Among Children, Adolescents, and Young Adults in India

Arsenic, a contaminant of groundwater and irrigated crops, is a global public health hazard. Exposure to low levels of arsenic through food extends well beyond the areas with high arsenic content in water. To identify cognitive impairments following commonly prevalent low-level arsenic exposure and characterize their underlying brain mechanisms. This multicenter population-based cohort study analyzed cross-sectional data of the Indian Consortium on Vulnerability to Externalizing Disorders and Addictions (cVEDA) cohort, recruited between November 4, 2016, and May 4, 2019. Participants aged 6 to 23 years were characterized using deep phenotyping measures of behavior, neuropsychology, psychopathology, brain neuroimaging, and exposure to developmental adversities and environmental neurotoxins. All analyses were performed between June 1, 2020, and December 31, 2021. Arsenic levels were measured in urine as an index of exposure. Executive function measured using the cVEDA neuropsychological battery, gray matter volume (GMV) from T1-weighted magnetic resonance imaging, and functional network connectivity measures from resting state functional magnetic resonance imaging. A total of 1014 participants aged 6 to 23 years (589 male [58.1%]; mean [SD] age, 14.86 [4.79] years) were included from 5 geographic locations. Sparse-partial least squares analysis was used to describe a negative association of arsenic exposure with executive function (r = -0.12 [P = 5.4 × 10-4]), brain structure (r = -0.20 [P = 1.8 × 10-8]), and functional connectivity (within network, r = -0.12 [P = 7.5 × 10-4]; between network, r = -0.23 [P = 1.8 × 10-10]). Alterations in executive function were partially mediated by GMV (b = -0.004 [95% CI, -0.007 to -0.002]) and within-network functional connectivity (b = -0.004 [95% CI, -0.008 to -0.002]). Socioeconomic status and body mass index moderated the association between arsenic and GMV, such that the association was strongest in participants with lower socioeconomic status and body mass index. The findings of this cross-sectional study suggest that low-level arsenic exposure was associated with alterations in executive functioning and underlying brain correlates. These results indicate potential detrimental consequences of arsenic exposure that are below the currently recommended guidelines and may extend beyond endemic risk areas. Precision medicine approaches to study global mental health vulnerabilities highlight widespread but potentially modifiable risk factors and a mechanistic understanding of the impact of low-level arsenic exposure on brain development.

Sources of geogenic arsenic in well water associated with granitic bedrock from Nova Scotia, Canada

Arsenic toxicity in drinking water is a global issue, with chronic exposure causing cancer and other health concerns. Groundwater from geochemically similar granites from mainland Nova Scotia, Canada, can have high and low levels of arsenic. The origin of this variation is uncertain, but different mineral hosts for arsenic could explain the disparity. The lability of arsenic from different minerals was assessed using laser ablation inductively coupled plasma mass spectrometry combined with calculations based upon well water data. Pyrite has the highest arsenic concentration (mean: 2300 μg/g, n = 9), is unstable in the groundwater system, and can release arsenic during oxidation. However, oxidation products replacing pyrite can adsorb arsenic, modifying the amount released. Cordierite has low arsenic concentrations (mean: 7.3 μg/g, n = 5) but is abundant and relatively soluble. Thus, cordierite could be a previously unrecognized source of arsenic in metapelitic rocks from metamorphic terranes. Pyrite from one of the granites studied was not oxidized, which in addition to the absence of cordierite in these same granites could account for the lower arsenic levels observed in associated well water. The results of this study can be used to identify potential geogenic sources of arsenic in other granitic terranes and reduce the risk of exposure through drinking water.

3D-printed device for the kinetic determination of As(III) in groundwater samples by digital movie analysis

High concentrations of inorganic arsenic in groundwater for human consumption is a worldwide common problem. Particularly, the determination of As(III) becomes important, since this species is more toxic than organic, pentavalent and elemental arsenic forms. In this work, a 3D-printed device that included a 24-well microplate was developed to perform the colourimetric kinetic determination of arsenic (III) by digital movie analysis. A smartphone camera attached to the device was used to take the movie during the process where As(III) inhibited the decolourization of methyl orange. The movie images were subsequently transformed from RGB to YIQ space to obtain a new analytical parameter called “d”, which was related to the chrominance of the image. Then, this parameter allowed the determination of the inhibition time of reaction (tin), which was linearly correlated with the concentration of As(III). A linear calibration curve (R = 0.9995) in the range from 5 μg L−1 to 200 μg L−1 was obtained. The method was precise (RSD = 1.2%), and the limits of detection (LOD) and quantification (LOQ) were 1.47 μg L−1 and 4.44 μg L−1, respectively. These values were lower than the limit established by the World Health Organization for total arsenic in drinking water (10 μg L−1). The accuracy of the method was assessed by a recovery study with optimal results (94.3%–104.0%). Additionally, the Analytical GREEnness metric approach was applied, obtaining a score 1.7 times higher than previously published works. The method is simple, portable and low-cost, being in compliance with various principles of green analytical chemistry.

Arsenic pollution and associated human health hazards in Rupnagar district, Punjab, India.

The hydrosphere although covering almost 70% of the Earth contributes only 3% of fresh water out of which groundwater covers almost 98%. The presence of some unwanted substance in this limited natural resource causes pollution when the substance causes serious harm to human beings and to the total ecosystem in a way. Arsenic is such a pollutant that is most naturally released in groundwater and long-term exposure to As-rich groundwater causes skin lesions and often leads to different types of cancers in humans. Rupnagar district in the Malwa region of Punjab is situated alongside the river Satluj which is one of the five important tributaries of Indus. The lowest reported concentration of As in this district is 10µg/L and the highest is 91µg/L. The higher values of As (> 50µg/L) that are above the permissible limit of IS 10500, 2004 in drinking water, are dominantly found in the western and south-western parts of the district. The average hazard quotient (HQ) indicates high risk for the consumers of the As-polluted groundwater in the district. The present study deals with the major cause of high arsenic (As) concentration in groundwater and its correlation with intensive agriculture in the Rupnagar district. Owing to the large size of the district, GIS techniques like ArcGIS 10.4.1 and QGIS 3.22.8 software were used for analysis in this study. The study reveals that high As concentration (> 50µg/L) is mostly found in agricultural lands and moderate concentration of As (10-50µg/L) in groundwater is distributed all over the district and are mostly reported from the urbanised areas. Overall, the water table shows a declining trend but no such decline is observed in the western and south-western parts of the district. As pollution in groundwater can also be caused due to water level decline owing to intensive agriculture and rapid water abstraction though As is naturally sourced in groundwater. A detailed study using the geochemical analysis of groundwater in the district can be effective in clearing out the scenario in the study area.

Arsenic Uptake, Transport, Accumulation in Rice and Prospective Abatement Strategies - A Review

Recent reports claim that arsenic (As) toxicity affects millions of individuals worldwide. A significant problem for rice output and quality as well as for human health is the high content of arsenic (As), a non-essential poisonous metalloid, in rice grains. Therefore, substantial research has been done on the interactions between rice and As in recent years. As rice plants uptake at the root surface is impacted by factors like radical oxygen loss and iron plaque. The absorption and movement of various As species as well as the transfer to sub cellular compartments include a multitude of transporters, including phosphate transporters and aquaglyceroporins. As III and AsV are transported into the root by phosphate transporters and intrinsic channels that mimic nodulin 26. The silicic acid transporter may have a substantial impact on how methylated As, dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA), enter the root. The issue of As contamination in rice is being addressed by researchers and practitioners to the best of their abilities. Making better plans may be aided by recent research on rice that explains the processes of arsenic ingestion, transportation, and metabolism at the rhizosphere. Common agronomic techniques, such as collecting rainwater for agricultural irrigation, using natural substances that aid in the methylation of arsenic, and biotechnology methods, may be investigated in an effort to lessen the uptake of arsenic by food crops. Innovative agronomic techniques and recent research findings on arsenic contamination in rice crops will be included in this review.

Effect of arsenic stress on the intestinal structural integrity and intestinal flora abundance of Cyprinus carpio.

Aquatic organisms such as fish can accumulate high concentrations of arsenic (As), which has toxic effects on fish. However, whether the intestinal flora are involved in As damage to fish intestinal tissues and the underlying process are unclear. Common carp (Cyprinus carpio) were exposed to As (2.83 mg/L) in water for 30 days, and blood, muscle, intestine, and intestine samples were collected. Intestinal pathological sections were observed, and the lipopolysaccharide (LPS) levels in serum and the levels of As accumulation and tight junction-related factors in intestinal tissues were measured. The gut microbiota was analysed by 16S rRNA sequencing. The results showed that As treatment decreased the abundance of microbiota, increased the number of harmful bacteria, and decreased the number of beneficial bacteria in the intestine. In our experiment, the top 30 harmful and beneficial bacteria with the highest relative abundance were identified. Among the top 30 harmful and beneficial bacteria, As treatment resulted in a significant (P < 0.05) increase in harmful bacteria (such as Fusobacteriota, Bacteroidota (LPS-producing bacteria), Verrucomicrobiota, Bacteroides, Aeromonas, and Stenotrophomonas) and a significant (P < 0.05) decrease in beneficial bacteria (such as Actinobacteriota, Planctomycetota, Firmicutes, Reyranella, Akkermansia, and Pseudorhodobacter), which further demonstrated that As affects the abundance of intestinal flora. In addition, As exposure increased the LPS level in serum and the abundance of Bacteroidota (LPS-producing bacteria) in the intestine. Bacteroidota exhibits the six highest relative abundance at the phylum level, which indicates that LPS produced by Bacteroidota can increase the LPS level in serum. Additionally, the protein and gene levels of the tight junction markers ZO-1 and occludin in the intestine were reduced by As treatment, which further indicated that As exposure impaired the structural integrity of the intestine. In conclusion, the results obtained in our study indicate that the intestinal flora, LPS, and tight junctions participate in the impairment of the structural integrity of the common carp intestine resulting from As exposure.

Relations between personal exposure to elevated concentrations of arsenic in water and soil and blood arsenic levels amongst people living in rural areas in Limpopo, South Africa

Exposure to arsenic even at low levels can lead to adverse health outcomes, however, there is a paucity of research from South Africa in relation to human exposure to arsenic. We investigated long-term exposure of residents in Limpopo province, South Africa, in a cross-sectional study by analysing water, soil and blood arsenic concentrations from two arsenic-exposed (high and medium–low exposure) villages and one non-exposed (control) village. There were statistically significant differences in the distribution of arsenic in water, soil and blood amongst the three sites. The median drinking water arsenic concentration in the high-exposure village was 1.75 µg/L (range = 0.02 to 81.30 µg/L), 0.45 µg/L (range = 0.100 to 6.00 µg/L) in the medium- / low-exposure village and 0.15 µg/L (range = < limit of detection (LOD) to 29.30 µg/L) in the control site. The median soil arsenic concentration in the high-exposure village was 23.91 mg/kg (range = < LOD to 92.10 mg/kg) whilst arsenic concentrations were below the limit of detection in all soil samples collected from the medium-/low-exposure and control villages. In the high-exposure village, the median blood arsenic concentration was 1.6 µg/L (range = 0.7 to 4.2 µg/L); 0.90 µg/L (range = < LOD to 2.5 µg/L) in the medium-/low-exposure village and 0.6 µg/L (range = < LOD to 3.3 µg/L) in the control village. Significant percentages of drinking water, soil and blood samples from the exposed sites were above the internationally recommended guidelines (namely, 10 µg/L, 20 mg/kg and 1 µg/L, respectively). Majority of participants (86%) relied on borehole water for drinking and there was a significant positive correlation between arsenic in blood and borehole water (p-value = 0.031). There was also a statistically significant correlation between arsenic concentrations in participants’ blood and soil samples collected from gardens (p-value = 0.051). Univariate quantile regression found that blood arsenic concentrations increased by 0.034 µg/L (95% CI = 0.02–0.05) for each one unit increase in water arsenic concentrations (p < 0.001). After adjusting for age, water source and homegrown vegetable consumption in multivariate quantile regression, participants from the high-exposure site had significantly higher blood concentrations than those in the control site (coefficient: 1.00; 95% CI = 0.25–1.74; p-value = 0.009) demonstrating that blood arsenic is a good biomarker of arsenic exposure. Our findings also provide new evidence for South Africa on the association between drinking water and arsenic exposure, emphasising the need for the provision of potable water for human consumption in areas with high environmental arsenic concentrations.

Spatial and seasonal variation of arsenic speciation in Pantanal soda lakes

The occurrence of high arsenic concentrations (up to 3000 μg L−1) in water of soda lakes of the Pantanal wetland is a remarkable case of natural arsenic contamination in South America. However, little is known about arsenic speciation in this environment, particularly regarding speciation changes related to lake trophic status and seasonal variations. To fill this gap, arsenic speciation analysis was carried out in surface (SW) and subsurface (SSW) waters sampled in five soda lakes with different eutrophication status, in two dry and one wet season. As(V) was the dominant species in these waters, while As(III), DMA, MMA and likely complex organic species were present in lower amounts. The results allow to conclude that the arsenic speciation in SW and SSW varies seasonally according to the regional wet or dry periods and lake water levels. In eutrophic turbid and in oligotrophic vegetated soda lakes, arsenic speciation was also characterized by spatial differences between edge and center or between the SW and SSW. Cyanobacteria or macrophytes/algae are involved in arsenic biotransformation in soda lakes through its metabolic and detoxification processes. Significant variation in surface water arsenic speciation occurs as a result of seasonal primary production fluctuation or water arsenic concentration changes in the soda lakes, increasing organoarsenics in dry periods, whereas in flood periods, As(V) prevails. Spatial distribution of arsenic species is significantly impacted by biogeochemical conditions at the water/sediment interface in soda lakes.

Method for establishing soil contaminant discharge inventory: An arsenic-contaminated site case study

The existing method to survey site pollution is generally based on soil-groundwater sampling and instrumental analysis, which enables us to access the detailed soil pollution status while lacking quantitative association with industrial activities. It is urgent to understand contaminant discharge modes and establish a discharge inventory for achieving process-targeted pollution control. This study took a 40-year phosphate fertilizer-sulfuric acid site as an example and constructed a contaminant tracing method based on on-site investigations and detailed industrial data. These investigations and data were combined to determine the characteristic pollutant of this site, arsenic. And the calculation process of four-pathway pollution modes (atmospheric deposition, wastewater, solid waste leaching, and storage dripping) is derived from the existing acceptance criteria and risk assessment guidelines. They are set to calculate the arsenic's factory-to-soil discharge flux. The absent process contaminant release information and parameters, such as discharge coefficient, were obtained from soil-groundwater pollution control standards and discharge handbooks. It was found that the high concentration of arsenic (around 1930 mg g−1) was preponderantly caused by sulfur-iron slag and tailing leaching (96.19%), while the other pathways accounted for only 0.13% (atmospheric deposition), 3.59% (wastewater) and 0.09% (storage tank). Results were verified by the measured arsenic concentration, and the difference was +16.29%, which was acceptable. Finally, a contaminant discharge inventory was established with high-resolution spatial distribution and time-scale (historical discharge) evolution. The innovation of this study lies in the preliminary construction of a method for formulating soil discharge inventory. This study would contribute to the refined management of site pollution and reduction of source contaminants discharge. In addition, it will help infer the pollution condition of sites that are difficult to sample so as to help the government achieve precise source control.

Diosmin exerts hepatoprotective and antihyperglycemic effects against sodium arsenite-induced toxicity through the modulation of oxidative stress and inflammation in mice

BackgroundChronic exposure to high concentrations of inorganic arsenic (NaAsO2) in drinking water is related to an increase in the risk of liver toxicity and diabetes. Diosmin has various pharmacological properties, including antioxidant and anti-inflammatory properties. This study was designed to investigate the protective effects of diosmin on diabetes and hepatotoxicity caused by NaAsO2. MethodsSixty male 8-week-old NMRI mice, weighing 25 ± 2 g, were randomly selected and put into six groups. The control (Group 1) was treated orally with distilled water, group 2 was treated with diosmin (100 mg/kg, p.o), group 3 received NaAsO2 (10 mg/kg, p.o), and groups 4, 5, 6 received diosmin (25, 50, 100 mg/kg, p.o), respectively and NaAsO2 (10 mg/kg, p.o). After 29 days, fasting blood sugar (FBS) measurement and glucose tolerance test were done. The mice were sacrificed on day 31, and blood and tissue (liver and pancreas) samples were taken. Then, serum and tissue samples were studied for biochemical and histological evaluations. ResultsThe results demonstrated that diosmin ameliorated glucose intolerance and decreased FBS compared to the NaAsO2 group. Diosmin (50 and 100 mg/kg) improved the serum factors of liver function (alanine aminotransferase, aspartate transaminase, and alkaline phosphatase) in the groups receiving NaAsO2. Moreover, increased levels of nitric oxide, tumor necrosis factor-alpha, and thiobarbituric acid reactive substances in liver tissue induced by NaAsO2 were diminished by diosmin treatment. Administration of diosmin increased total thiol and enzymatic activities of catalase, superoxide dismutase, and glutathione peroxidase in liver tissue. Furthermore, treatment with diosmin reduced the increase in protein amount of Sirtuin 3 and nuclear factor kappa B in the groups receiving NaAsO2. Also, the liver and pancreas histological lesions induced by NaAsO2 were attenuated by diosmin treatment. ConclusionDiosmin has a preventive effect against hepatotoxicity and diabetes induced by NaAsO2 in mice through its antioxidant and anti-inflammatory properties.