Inorganic Arsenic Compounds Research Articles

Приоритетные факторы риска питьевой воды систем централизованного питьевого водоснабжения, формирующие негативные тенденции в состоянии здоровья населения

Our research object was long-term dynamics of parameters describing drinking water from centralized water supply systems and additional cases of health disorders among population in Russia directly caused by low-quality drinking water. Our research goal was to perform hygienic assessment of priority risk factors related to drinking water and potential health disorders that could be caused by them. Our research technique was hygienic analysis of drinking water parameters as per data taken from the federal statistical form No. 18 entitled «Data on sanitary situation in a RF region» over 2000–2019, the federal information fund of social and hygienic monitoring over 2012–2019, and calculation of associated health disorders as per MG 5.1.0095–14. Specific weight of centralized water supply sources that didn’t conform to sanitary-epidemiologic requirements decreased by 4.7 % over 2000–2019 and amounted to 14.9 %. Over the last 20 years there has been a descending trend in specific weight of water samples taken from centralized water supply sources that don’t conform to sanitary requirements as per sanitary-chemical parameters (by 2.7 %) and microbiological parameters (by 4.8%). Over 2000–2019, specific weight of water distribution networks not conforming to sanitary-epidemiologic requirements decreased by 10.7 % and amounted to 15.9 % in 2019. Over the last 20 years there has been an increase in quality of drinking water taken from centralized distribution networks. Specific weight of water samples from centralized distribution networks not conforming to sanitary requirements as per microbiological and sanitary-chemical parameters fell by 6.7 % and 7.9 % respectively. In 2012–2019 in the RF hygienic parameters of drinking water quality were the most violated as per contents of bromine, silicon, chlorine, iron, sodium, lithium, magnesium, manganese, chloroform, boron, strontium, sulfides, and hydrogen sulphide. Overall, in the RF in 2019 more than 1.66 million cases of digestive diseases, cardiovascular diseases, diseases of skin and subcutaneous tissue, and other health disorders were directly related to drinking water being contaminated with chemicals and microbiological agents; it was by 13.3 % lower than in 2012 regarding morbidity associated with drinking water quality. Priority risk factors were chlorine, chlorine organic compounds (COC), ammonia, iron, manganese, arsenic, nickel, copper, boron, magnesium, and other compounds.

Priority risk factors related to drinking water from centralized water supply system that create negative trends in population health

Our research object was long-term dynamics of parameters describing drinking water from centralized water supply systems and additional cases of health disorders among population in Russia directly caused by low-quality drinking water. Our research goal was to perform hygienic assessment of priority risk factors related to drinking water and potential health disorders that could be caused by them. Our research technique was hygienic analysis of drinking water parameters as per data taken from the federal statistical form No. 18 entitled «Data on sanitary situation in a RF region» over 2000–2019, the federal information fund of social and hygienic monitoring over 2012–2019, and calculation of associated health disorders as per MG 5.1.0095–14. Specific weight of centralized water supply sources that didn’t conform to sanitary-epidemiologic requirements decreased by 4.7 % over 2000–2019 and amounted to 14.9 %. Over the last 20 years there has been a descending trend in specific weight of water samples taken from centralized water supply sources that don’t conform to sanitary requirements as per sanitary-chemical parameters (by 2.7 %) and microbiological parameters (by 4.8%). Over 2000–2019, specific weight of water distribution networks not conforming to sanitary-epidemiologic requirements decreased by 10.7 % and amounted to 15.9 % in 2019. Over the last 20 years there has been an increase in quality of drinking water taken from centralized distribution networks. Specific weight of water samples from centralized distribution networks not conforming to sanitary requirements as per microbiological and sanitary-chemical parameters fell by 6.7 % and 7.9 % respectively. In 2012–2019 in the RF hygienic parameters of drinking water quality were the most violated as per contents of bromine, silicon, chlorine, iron, sodium, lithium, magnesium, manganese, chloroform, boron, strontium, sulfides, and hydrogen sulphide. Overall, in the RF in 2019 more than 1.66 million cases of digestive diseases, cardiovascular diseases, diseases of skin and subcutaneous tissue, and other health disorders were directly related to drinking water being contaminated with chemicals and microbiological agents; it was by 13.3 % lower than in 2012 regarding morbidity associated with drinking water quality. Priority risk factors were chlorine, chlorine organic compounds (COC), ammonia, iron, manganese, arsenic, nickel, copper, boron, magnesium, and other compounds.

Development of a fast and sensitive method for the determination of As(III) at trace levels in urine by differential pulse anodic voltammetry using a simple graphene screen–printed electrode

A simple and fast anodic voltammetric method was employed to determine traces of As(III) in urine samples using commercial screen–printed graphene electrodes without subsequent modification. To obtain a sensitive and selective method for As(III) determination, the effects of various parameters such as pH, supporting electrolyte concentration, accumulation potential (Eacc), accumulation time (tacc), and potential scan conditions were studied. The optimum experimental conditions were chosen to be as follows: pH of 2.8 (0.01 mol L−1 phosphate buffer), scan increment of 4 mV, pulse width of 80 ms, pulse period of 0.5 s, and pulse amplitude of 200 mV. Differential pulse voltammograms were obtained by scanning from −0.80 V to 0.80 V without applying an accumulation step. Under these conditions, one peak was observed at 0.27 V due to As0 oxidation. After optimizing the experimental conditions, the anodic peak current for As was found to be linearly related to its concentration up to ca. 5.0 μg L−1, with detection and quantitation limits (DLs, QLs) of 0.28 µg L−1 and 0.92 µg L−1, respectively. The developed method was validated by the determination of As(III) in spiked tap water from our laboratory, which showed an As(III) concentration of 50.64 ± 0.10 μg L−1 (spiked with 50.0 μg L−1); two urine samples (where As was not detected) spiked with As(III) 0.73 μg L−1 and 0.91 μg L−1 (in the cell) showed an As(III) concentration of 0.70 μg L−1 and 0.91 μg L−1, respectively. The method was successfully applied to the determination of Astotal in 16 urine samples obtained from workers occupationally exposed to inorganic arsenic compounds without previous treatment. The results obtained for Astotal were compared with measurements made by an external analytical laboratory, which used HG–AAS. To determine Astotal, As(V) was reduced in the presence of thiosulfate in an acid medium. The electrode showed good stability and repeatability.

A new one‐dimensional coordination polymer synthesized from zinc and guanazole: Superior capture of organic arsenics

Organic arsenic compounds in the environment are a global threat to human health. This threat has created the urgency to develop highly efficient adsorbents with both high adsorption capacity and versatile removal of different arsenic compounds. A novel 1D zinc(II) coordination polymer, formulated as Zn2(datrz)2(bpy)Cl2 (BUC‐70) (datrz = guanazole, bpy = 4,4′‐bipyridine), was successfully synthesized through slow evaporation at room temperature. BUC‐70 exhibited an excellent adsorption capacity toward p‐arsanilic acid (p‐ASA) and roxarsone (ROX) in water, which could be ascribed to As–O–Zn bonding interactions and strong hydrogen‐bonding interactions between the organic arsenics and BUC‐70. The maximum adsorption capacities toward p‐ASA and ROX were 738 and 937 mg·g−1, respectively. BUC‐70 was effective in the removal of p‐ASA and ROX at low concentrations (<5 mg·l−1) from the simulated p‐ASA and ROX wastewater. Furthermore, the as‐synthesized BUC‐70 exhibited good adsorption property toward p‐ASA and ROX in wastewater simulated by lake water and tap water. After adsorptive treatment using BUC‐70, the concentrations of both p‐ASA and ROX were lower than the required concentrations of the drinking water standard of the World Health Organization and the surface water standard of China. Continuous‐flow, fixed‐bed column experiments were performed using BUC‐70 loaded on cotton as packing material to explore the potential large‐scale application.

Estimating Soil Arsenic Content with Visible and Near-Infrared Hyperspectral Reflectance

Soil arsenic (AS) contamination has attracted a great deal of attention because of its detrimental effects on environments and humans. AS and inorganic AS compounds have been classified as a class of carcinogens by the World Health Organization. In order to select a high-precision method for predicting the soil AS content using hyperspectral techniques, we collected 90 soil samples from six different land use types to obtain the soil AS content by chemical analysis and hyperspectral data based on an indoor hyperspectral experiment. A partial least squares regression (PLSR), a support vector regression (SVR), and a back propagation neural network (BPNN) were used to establish a relationship between the hyperspectral and the soil AS content to predict the soil AS content. In addition, the feasibility and modeling accuracy of different interval spectral resampling, different spectral pretreatment methods, feature bands, and full-band were compared and discussed to explore the best inversion method for estimating soil AS content by hyperspectral. The results show that 10 nm + second derivative (SD) + BPNN is the optimum method to predict soil AS content estimation; R v 2 is 0.846 and residual predictive deviation (RPD) is 2.536. These results can expand the representativeness and practicability of the model to a certain extent and provide a scientific basis and technical reference for soil pollution monitoring.

Ionic imprinted polymer solid-phase extraction for inorganic arsenic selective pre-concentration in fishery products before high-performance liquid chromatography – inductively coupled plasma-mass spectrometry speciation

Low levels of inorganic arsenic [As(III) and As(V)] in fishery products have been selectively isolated from fish extracts (1.0 g of wet fish samples pre-treated with 10 mL of 1:1 methanol/water under sonication at 25 °C for 30 min) by ionic imprinted polymer (IIPs) based solid phase extraction procedure (on-column mode). The selective adsorbent was synthesized using sodium (meta) arsenite as a template, 1-vinyl imidazole as a functional monomer, divinylbenzene as a cross-linker, and 2,2′-azobisisobutyronitrile as an initiator. Optimized pre-concentration conditions imply fish extract (10 mL) pH adjustment at 8.5 before loading (flow rate of 0.25 mL min−1), and elution with ultrapure water (2 mL) at 0.50 mL min−1. A pre-concentration factor of 50 was finally obtained after evaporation to dryness (N2 stream) and re-dissolution in 0.2 mL of ultrapure water before HPLC-ICP-MS. Synthesized material was found to pre-concentrate inorganic arsenic species; whereas organic arsenic compounds, mainly arsenobetaine (the major organoarsenic compound in fish/seafood products), were not found to interact with the adsorbent. The developed selective method gave limits of quantification of 1.05 and 1.31 µg kg−1 for As (III) and As (V), respectively, and good precision [relative standard deviations lower than 12% in fish extracts spiked at several As (III) and As (V) levels]. The proposed method was finally applied to the selective determination of As (III) and As (V) species in several fishery products.

Capillary electrophoresis coupled to electrospray mass spectrometry for the determination of organic and inorganic arsenic compounds in water samples

Some compounds of arsenic are extremely toxic to the human body even at low levels. Long-term exposure from drinking contaminated water causes adverse health effects. This has led the European Union and other global organizations to reduce the maximum residue limit for the total arsenic up to 10 μg L−1 in water for human consumption. The toxicity of arsenic depends on the oxidation state, chemical structure and solubility in the biological environment. Main analytical procedures report on the determination of arsenic species in water samples which have been developed based on atomic spectroscopy –speciation performed in the sample treatment step– and inductively coupled plasma-mass spectrometry (ICP-MS). In such cases, speciation is performed by coupling to high-performance liquid chromatography (HPLC). As far as we know, the determination of arsenic species in water samples at low concentration levels by capillary electrophoresis (CE) coupled to electrospray mass spectrometry (ESI-MS) has not been described up to now. In this research CE-ESI(−)-MS is proposed for the identification and simultaneous quantification of organic and inorganic arsenic species in water samples for human consumption. The target compounds were dimethylarsinate (DMA), mono-methylarsonate (MMA), arsenite (i-As(III)) and arsenate (i-As(V)). Optimization of the composition and nature of both the electrophoretic separation medium –using hexafluoro-2-propanol (HFIP) as an additive– and the sheath liquid was performed and aimed at achieving the best sensitivity and separation efficiency for the CE-ESI(−)-MS coupling. Two simple sample treatments were proposed: one based on dispersive liquid-liquid micro-extraction (DLLME) intended for a rapid determination of the total content of inorganic arsenic in the water sample; and the second based on partial evaporation of the water sample to detect each of the four main arsenic species. For the second, limits of detection between 0.02 and 0.04 μg L-1 were found, which are similar results as the ones achieved with methods based on HPLC-ICP-MS.The DLLME + CE-ESI(−)-MS method was applied to the determination of total inorganic arsenic in eleven water samples in the province of Salamanca (Spain). Five of the analyzed samples had values close to, or superior to the maximum residue limit for the total of arsenic in water intended for human consumption (10 μg L-1). The validated method CE-ESI(−)-MS for arsenic speciation was applied with success to the analysis of the weakly mineralized water sample (dry residue < 50 mg L-1) of both groundwater and bottled water.

MORTALITY DUE TO MALIGNANT TUMORS IN WORKERS EMPLOYED IN THE COMPLEX PROCESSING OF COPPER METALLURGICAL WASTE

Introduction. Workers engaged in the complex processing of copper metallurgy waste are in contact with inorganic compounds of arsenic, nickel, lead, cadmium, and hexavalent chromium. The purpose of the study is to estimate the degree of carcinogenic risk for workers employed in the processing of copper metallurgy waste. Material and methods. The results of a retrospective study of deaths from cancer of workers in the recycling of copper metallurgy (sulfuric acid, bluestone and nickel vitriol production and processing of anode slimes) of a metallurgical plant to produce blister and refined copper are presented. The intensity of mortality and relative carcinogenic risk for workers were calculated (common as well as age-specific for men and women). A comparison of the observed and “expected” indices of the cancer mortality rate was carried out and the relative carcinogenic risk for workers was determined. Results. The highest levels of cancer mortality were found in the age range of 50-59 years. It’s noted excess observed mortality from malignant tumors over “expected” both men and women in most cancer locations. For men involved in the production of sulfuric acid, a high carcinogenic risk of developing malignant neoplasms of urinary organs. For women involved in the production of sulfuric acid, a high carcinogenic risk of developing malignant neoplasms of the liver. When receiving copper sulfate, men have the greatest carcinogenic risk for urinary organs for tumors, and women for lymphatic and hematopoietic tissue tumors. The processing of anodic sludges is associated with a carcinogenic risk for men on lung cancer, and for a woman - on tumors of lymphatic and hematopoietic tissue. Conclusion. Obtained epidemiological data indicate carcinogenic risk to workers involved in the complex recycling of copper metallurgy.

The role of small molecules in restricting rice accumulation of dimethylarsinic acid

Dimethylarsinic acid (DMA), an organic arsenic compound found in rice grain, is a causal agent of straighthead disorder, which can decimate yields. To minimize rice accumulation of DMA, we tested 9 molecules for antagonistic effects with DMA. We also tested whether the source of nitrogen is able to affect DMA uptake, as DMA is a weak acid and different nitrogen sources have differing effects on rhizospheric pH. We grew rice (Oryza sativa L. cv. Lemont) hydroponically to maturity in two different experiments. First, 9 potential competitors (boric acid, calcium, glycerol, glycine, lactic acid, phosphoric acid, serine, silicic acid, and urea) were included in the hydroponic solution at a molar ratio ≥ 100:1 competitor:DMA. Second, rice receiving 5 μM DMA was grown under ammonium, nitrate, or a 1:1 mix of ammonium and nitrate. Yield metrics and plant elemental concentrations were measured after harvest. Of the potential competitors, only silicic acid was able to alleviate straighthead disorder and no competitors were able to reduce grain As by ≥30%. Under differing nitrogen sources, nitrate decreased plant concentrations of As relative to ammonium, but not in the grain. While Si can alleviate DMA uptake, there remains uncertainty in how most DMA enters the plant.

Смертность от злокачественных новообразований работающих, занятых в комплексной переработке отходов металлургии меди

Introduction. Workers engaged in the complex processing of copper metallurgy waste are in contact with inorganic compounds of arsenic, nickel, lead, cadmium, and hexavalent chromium. The purpose of the study is to estimate the degree of carcinogenic risk for workers employed in the processing of copper metallurgy waste. Material and methods. The results of a retrospective study of deaths from cancer of workers in the recycling of copper metallurgy (sulfuric acid, bluestone and nickel vitriol production and processing of anode slimes) of a metallurgical plant to produce blister and refined copper are presented. The intensity of mortality and relative carcinogenic risk for workers were calculated (common as well as age-specific for men and women). A comparison of the observed and “expected” indices of the cancer mortality rate was carried out and the relative carcinogenic risk for workers was determined. Results. The highest levels of cancer mortality were found in the age range of 50-59 years. It’s noted excess observed mortality from malignant tumors over “expected” both men and women in most cancer locations. For men involved in the production of sulfuric acid, a high carcinogenic risk of developing malignant neoplasms of urinary organs. For women involved in the production of sulfuric acid, a high carcinogenic risk of developing malignant neoplasms of the liver. When receiving copper sulfate, men have the greatest carcinogenic risk for urinary organs for tumors, and women for lymphatic and hematopoietic tissue tumors. The processing of anodic sludges is associated with a carcinogenic risk for men on lung cancer, and for a woman - on tumors of lymphatic and hematopoietic tissue. Conclusion. Obtained epidemiological data indicate carcinogenic risk to workers involved in the complex recycling of copper metallurgy.

Изучение токсичности мышьяксодержащих соединений, выделенных из бурой водоросли Saccharina japonica, на лабораторных животных

The ability of various marine organisms, especially algae and invertebrates, to accumulate arsenic in high concentrations can pose a threat to public health when consumed. It is known from the literature that inorganic arsenic compounds (arsenites and arsenates) are the most toxic, in comparison with methylated forms of the element, and especially with complex organic compounds (arsenobetain, arsenocholine, tetramethylarsonium, arsenoriboses), which are considered non-toxic for live organisms. Monitoring of safety indicators of aquatic biological resources in the main commercial basins of the Russian Federation has shown that the most common excess of total arsenic content is characteristic for algae. According to TR CU 021/2011, the total arsenic content in algae should be 5 mg / kg and the established norm without separation of organic and inorganic arsenic compounds creates a barrier to the rational use of seafood. In this regard, the justification of the norms for the content of inorganic arsenic in algae and the assessment of their toxicity is a very urgent problem. Study of the samples of commercial brown algae Saccharina (=Laminaria) japonica and its derivates with ICP-MS, HPLC–MS-ISP methods, the maximum permissible level of arsenic was found to be exceeded, but the most toxic inorganic forms made up from 6 to14 % of the total amount of arsenic in the raw material. Acute toxicity on laboratory animals (rats) was studied and the absence of toxic effects was shown when an oral suspension containing high doses of arsenic was administered. Repeated administration of the same substances to laboratory mice of the CD 1 line has shown no toxic effects even after multiple doses of arsenic isolated from algae.

Soil attribute regulates assimilation of roxarsone metabolites by rice (Oryza sativa L.)

Roxarsone (ROX), an organoarsenic feed additive, and its metabolites, can be present in animal manure used to fertilize rice. Rice is prone to absorb arsenic, and is subject to straighthead disorder, which reduces rice yield and is linked with organic arsenic compounds. This study aims to elucidate how soil property affect arsenic accumulation in rice plants fertilized with chicken manure containing ROX metabolites. Manures of chickens fed without or with ROX, designated as control manure and ROX treated manure (ROXCM), respectively, were applied in eight paddy soils of different origins, to investigate the assimilation of arsenic species in rice plants. The results show that inorganic arsenic (arsenate and arsenite), monomethylarsonic acid and dimethylarsinic acid (DMA) were detected in all brown rice and husk, trace tetramethylarsonium and trimethylarsine oxide were occasionally found in these both parts, whereas all these arsenic species were determined in straw, irrespective of manure type. ROXCM application specifically and significantly increased brown rice DMA (P = 0.002), which remarkably enhanced the risk of straighthead disease in rice. Although soil total As impacted grain biomass, soil free-iron oxides and pH dominated arsenic accumulation by rice plants. The significantly increased grain DMA suggests manure bearing ROX metabolites is not suitable to be used in soils with abundant free-iron oxides and/or high pH, if straighthead disorder is to be avoided in rice.

Problems of Establishing Limits for Arsenic Content in Brown Algae and Brown Algae-Containing Medicinal Products

Algae tend to accumulate elemental toxic substances in high concentrations. Algae are widely used in the food and pharmaceutical industries, and this dictates the need to establish limits for the content of toxic substances that they may contain. The aim of the study was to analyse the requirements of the Russian and foreign pharmacopoeias and other regulatory documents concerning the limits for the content of arsenic in brown algae. The paper presents the results of analysis of monographs from the State Pharmacopoeia of the Russian Federation, XIII and XIV editions, draft version of the Pharmacopoeia of the Eurasian Economic Union, United States Pharmacopoeia, Japanese Pharmacopoeia, European Pharmacopoeia, and Ayurvedic Pharmacopoeia of India containing limits for the content of arsenic in herbal medicinal products (HMPs). In addition, the authors analysed Russian, international and foreign food industry and dietary supplements regulations, as well as scientific publications on arsenic content in brown algae. They also considered the nomenclature of arsenic compounds to be determined and controlled in medicinal products, highlighted the main approaches to and identified global trends in establishing the limits for their content in HMPs. The paper summarises specific aspects of inorganic arsenic compounds accumulation by brown algae. It was demonstrated that the majority of foreign pharmacopoeias either have specific norms for arsenic content in brown algae, which differ from the norms for HMPs, or have general norms that take into account different toxicity levels of organic and inorganic arsenic compounds. There is a tendency to control the content of elemental toxic substances based on their maximum allowable daily intake. The paper substantiates the need for separate determination of toxic inorganic arsenic compounds and potentially toxic methyl arsonate and dimethyl arsinate in HMPs.

Gene expression and DNA methylation regulation of arsenic in mouse bladder tissues and in human urothelial cells.

According to a report of the International Agency for Research on Cancer, arsenic and inorganic arsenic compounds are classified into Group 1 carcinogens with regard to human health. Epidemiological studies indicate that arsenic is one of the main risk factors for the development of bladder cancer. In the present study, arsenic-altered gene expression in mouse bladder tissues and in human urothelial cells was compared. In the mouse model, sodium arsenite-induced mouse urothelial hyperplasia and intracellular inclusions were present. Following DNA array analysis, four genes with differential expression were selected for quantitative real-time PCR assay. The genes were the following: Cystathionine β-synthase (CBS), adenosine A1 receptor (ADORA1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and Wnt inhibitory factor 1 (Wif1). The results indicated a significant increase in the levels of Cbs and Adora1. The analysis of the DNA CpG methylation levels of the mouse Cbs and Adora1 genes revealed no significant change. In contrast to these observations, the four genes were further analyzed in the human normal urothelial cell line SV-HUC1. The data indicated that WIF1 gene expression was decreased by sodium arsenite, whereas this was not noted for CBS, MALAT1 and ADORA1. Sodium arsenite decreased mRNA and protein expression levels of the WIF1 gene. In addition, the methylation levels of the WIF1 gene were increased. Sodium arsenite inhibited cell proliferation and promoted cell migration as demonstrated in cell functional assays. The gene status was compared in 8 human urothelial cell lines, and WIF1 mRNA expression levels were determined to be higher, whereas DNA CpG methylation levels were lower in SV-HUC1 cells compared with those noted in the other 7 bladder cancer cell lines. In summary, the data indicated that sodium arsenite decreased WIF1 gene expression and promoted cell migration. The increased methylation levels of WIF1 DNA CpG could be a potential biomarker for bladder cancer.

Effective and selective adsorption of organoarsenic acids from water over a Zr-based metal-organic framework

It is imperative to remove organicarsenic acids (OAAs) from water because they can convert into highly toxic inorganic arsenic compounds in natural environment via biotic and abiotic degradation routes. Herein, seven Zr-based metal-organic frameworks (Zr-MOFs) including DUT-67, UiO-66, UiO-67, MOF-808, MOF-808F, NU-1000, NU-1000B with various structures were screened for the adsorptive removal of representative OAAs including p-arsanilic acid (ASA) and roxarsone (ROX) in water media. Initial screening found that MOF-808 and MOF-808F have the largest adsorption capacities. Therefore, their adsorption behaviors including adsorption kinetics, isotherms, specificity and effects of pH were fully investigated. Remarkably, MOF-808F had the second largest maximum adsorption capacities of ASA (621.1 mg g−1) and ROX (709.2 mg g−1) among the reported MOF-based adsorbents. In addition, MOF-808F showed excellent selectivity and reusability and no observable drop of adsorption efficiency was found in the presence of equimolar competing ions (Cl−, OAc− or SO42−) or after three successive adsorptive runs. By contrast, MOF-808 had inferior adsorption specificity and reusability in spite of the very similar structure with MOF-808F. The structure-dependent adsorption performances can be explained by the distinct adsorptive mechanisms, which were revealed by zeta potential measurements, X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculation etc. The dominant interaction between MOF-808 and ASA was coordination interactions, while ASA adsorption over MOF-808F was governed by the synergistic effect of π-π stacking, hydrogen bonding, and electrostatic interactions. This work no only presented an excellent adsorbent (MOF-808F) toward OAAs, but also revealed the structure dependent adsorption performances/mechanisms.

Determination of Inorganic Arsenic in Seaweed and Seafood by LC-ICP-MS: Method Validation.

Background: Seaweed and seafood often contain both inorganic and organic arsenic compounds showing distinct toxicities. Speciation must be taken into account when determining the concentrations of arsenic compounds and how they relate to overall toxicity. Objective: An analytical method for the quantitation of inorganic arsenic was validated in seaweed and seafood. Methods: Food samples were heated at 100°C in 0.3 mol/L nitric acid. Arsenic speciation was quantitatively determined by LC-inductively coupled plasma-MS (LC-ICP-MS) using an octadecilsilane (ODS) column with a mobile phase containing an ion-pair reagent. Results: Limits of detection (0.0023-0.012 mg/kg), LOQ (0.0077-0.042 mg/kg), repeatability (3.0-7.4%), intermediate precision (4.4-7.4%), and trueness (recoveries 94-107%) of the proposed method were satisfactory for inorganic arsenic in seaweed and seafood. Inorganic arsenic was detected in almost all the evaluated dried seaweed products, the Japanese oyster, nam pla, oyster sauce, and the intestinal organs of seafood. Conclusions: Among the dried seaweed products, significant inorganic arsenic was detected in the brown algae akamoku, hijiki, and mozuku. The small amounts of inorganic arsenic detected in nam pla and oyster sauce likely derive from the internal organs of the raw seafood used in their preparation. Highlights: Arsenic speciation in seaweed and seafood was measured by LC-ICP-MS using an ODS column with a mobile phase containing an ion-pair reagent. Among the dried seaweed products, brown algae akamoku, hijiki, and mozuku contained significantly high levels of inorganic arsenic. The intestinal organs of oyster, sardine, and scallop contained higher arsenic levels than the muscles.

Arsenic species uptake and translocation in Elodea canadensis

The capacity of Elodea canadensis to phytofiltrate arsenic species from water was evaluated. Plants were adapted to tap water and supplemented with 15 and 250 µg L−1 of As. Inorganic arsenic species (As III, As V), and organic arsenic compounds: monomethylarsonate (MMA) and dimethylarsinate (DMA) were analyzed. Sampling was carried out at different times after exposure in culture water and plant organs. Plants exposed to 15 µg L−1 of As concentration showed no significant difference on As concentration (95% confidence level) in their organs compared to controls. When plants were exposed to 250 µg L−1 of As concentration, a significant increase of As concentration in plant organs was observed. After 1 h exposure, plants reduce 63.16% the As concentration in the culture water, with a bioaccumulation factor (BF) of 4.3. Under these conditions, E. canadensis accumulate As V in roots and do not translocate it to stems (transfer factor <1). MMA was determined in stems and leaves. E. canadensis effectively phytofiltrate As from tap water of a city located in an arsenic endemic area from concentrations of 36 µg L−1 to undetectable levels (10 ng L−1).

Selective detection of two representative organic arsenic compounds in aqueous medium with metal–organic frameworks

Two stable Al(iii)-MOFs were designed and synthesized for the selective detection of two organic arsenic compounds in aqueous medium.

USING THE METHODOLOGY OF CARCINOGENIC RISKS ASSESSMENT IN COPPER PYROMETALLURGY

We conducted a hygienic assessment of the chemical factors contribution of the production environment to the formation of carcinogenic risk of workers employed in the reverberatory and blast smelting of copper-containing ores, compared with autogenous processes. Inorganic arsenic compounds have been shown to be a major factor forming a carcinogenic risk in copper smelting. The greatest prognostic values of carcinogenic risk for similar professions of metallurgical shops are observed during reverberatory and blast smelting, rather than during bath smelting due to the difference in the equipment used. The main measure to reduce the carcinogenic risk of blister copper production should be the technical reequipment of smelters with the introduction of autogenous processes.

Interspecific differences in the bioaccumulation of arsenic of three Patagonian top predator fish: Organ distribution and arsenic speciation

Interspecific differences in arsenic bioaccumulation and organ distribution (muscle, liver, kidney and gills) in three predator fish (creole perch, rainbow trout and brown trout) from a Patagonian lake impacted by volcanic eruptions were studied. Arsenic in fish organs were compared analyzing: 1) temporal (before and after volcanic eruption) and spatial (near and far from the volcano) influence of Puyehue-Cordón Caulle volcanic complex activity on arsenic concentrations; 2) the influence of growth (as total length), organ type and their interactions over arsenic accumulation; and 3) arsenic speciation and total arsenic relationship with carbon to nitrogen ratios (C:N), as a proxy of lipid presence, in fish muscle. In general, total arsenic concentrations in creole perch organs were 2–7 times higher than those recorded in the corresponding organs of salmonids. Arsenic was preferentially accumulated in liver and kidney in the three fish species. The influence of the volcanic activity over arsenic concentrations was more evident in creole perch: organs from creole perch captured closest to the volcano exhibited higher arsenic concentrations. Temporal variations were not so consistent. No clear relationship between arsenic and fish length was observed. Positive and linear relationship between arsenic in all pair of organs was found in creole perch, while rainbow trout showed a quadratic relationship between muscle and the remaining organs, indicating different arsenic assimilation-elimination relationships between organs and fish. The arsenic liver:muscle ratio in the three fish species was greater than 1, suggesting some level of arsenic stress. Arsenobetaine (AB) and dimethylarsinic acid (DMA) were the dominant arsenic species in muscle of these fish, having creole perch 3–4 times higher AB than rainbow trout. A positive relationship between C:N ratio and total arsenic concentrations was found, with higher C:N in creole perchs near the volcano. In terms of food safety, no inorganic arsenic compound were detected, therefore arsenic levels in fish from Lake Nahuel Huapi does not represent any health risk to consumers.