Determination of As(III) in nonacidified groundwater samples for inorganic speciation analysis using flow injection hydride generation atomic absorption spectrometry

A flow injection system coupled to hydride generation atomic absorption spectrometry with heated quartz tube atomizer was employed for the selective determination of As(III) in real groundwater samples under nonacidic conditions. The use of low-acidity conditions was carefully evaluated in order to minimize the interconversion of redox arsenic species. The As(III) hydride was generated using 0.1 mol L-1 HCl as carrier solution and 0.2% (m/v) NaBH4 in 0.025% NaOH as the reductant. A coil reaction larger than the used one for higher acidity conditions (480 mm instead of 115 mm) was selected. The generated hydride was transported to the atomizer by a nitrogen flow of 75 ml min-1. The main parameters that influenced the signal intensity and shape were studied. Under the best found experimental conditions, a detection limit (3σ) of 1.0 μgL-1 As(III) was obtained for a 500 μl sample volume. The analytical recovery ranged between 90% and 98%. In addition, the total inorganic arsenic concentration in the samples was determined on sample aliquots acidified with concentrated HCl and prereduced with 5% (m/v) KI-5% (m/v) C6H8O6 solution. HCl 1.2 mol L-1 as carrier solution, NaBH4 0.2% (m/v) as reductant, and a nitrogen flow rate of 75 ml min-1 were used in this case. The concentration of As(V) was calculated by difference between the total inorganic arsenic and As(III) concentrations. © Taylor & Francis Group, LLC.Fil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química; ArgentinaFil: Beldomenico, Horacio Ramon. Universidad Nacional del Litoral. Facultad de Ingeniería Química; ArgentinaFil: Tudino, Mabel Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentin

Selenium speciation in soils using flow injection hydride generation atomic absorption spectrometry with on-line removal of organic matter interferences

A method based on flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) with an on-line pre-reduction of Se(VI) to Se(IV) was developed and optimized to determine phosphate-extractable Se (0.1 M phosphate buffer KH2PO4/K2HPO4 at pH 7). The extracted fraction involves water-soluble Se (i.e. the most mobile Se fraction) and exchangeable Se (i.e. sorbed onto soil component surface). Kinetic discrimination mechanisms allowed the complete removal of interferences caused by organic matter due to the formation of humic substances (HS)–Se(IV) complexes observed when batch pre-reduction processes were used. Se(IV) and Se(VI) recoveries ranged 95–105% at a fortification level of 150 μg kg−1. The pre-reduction was efficiently carried out in 20 s in a 6 M HCl medium at 100 °C. Results from phosphate-extractable fractions were comparable to those obtained by ICP-MS. Se bound to organic matter was released digesting the remaining material from the phosphate buffer extraction with 0.1 M K2S2O8. Detection and quantification limits were 15 μg kg−1 Se and 50 μg kg−1 Se, respectively, in each fraction. The methodology was applied to 10 agricultural soils from Argentina with total Se concentration levels between 130 μg kg−1 and 419 μg kg−1.Fil: Brusa, Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Tudino, Mabel Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Schlotthauer, Jonatan. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentin

Determination of selenium in selected food samples from Argentina and estimation of their contribution to the Se dietary intake

An optimised FI-HGAAS method was applied to determine the total selenium concentrations in selected high consumption food (fish, beef, chicken, milk, rice, wheat flour, egg) and to estimate their contribution to the Argentinean dietary intake, whose information is scarce nowadays. Through several optimisation steps a suitable method was achieved showing satisfactory figures of merit for all matrices. Average recovery was 96%, RSD < 5%, LODs ranged 2.0-7.0 μg kg-1 and the accuracy was assessed using DOLT-3 NRC certified reference material. Meat and eggs showed the highest values (in μg kg-1, beef: 42-153; chicken: 62-205; fish: 94-314; canned tuna: 272-282; eggs: 134-217), minor values were found for wheat flour (22-42), rice: (<22), pasta (47-64) and milk (<7-9). An estimated intake of 32 and 24 μg day-1 for adult men and women, respectively, suggested a deficient Se intake, leading to further comprehensive surveys of Se occurrence in Argentina.Fil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química; ArgentinaFil: Brusa, Lucila. Universidad Nacional del Litoral. Facultad de Ingeniería Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Campagnoli, Darío Ulises. Universidad Nacional del Litoral. Facultad de Ingeniería Química; ArgentinaFil: Beldomenico, Horacio Ramon. Universidad Nacional del Litoral. Facultad de Ingeniería Química; Argentin

Inter‐and intra-stock bioaccumulation of anionic arsenic species in an endangered catfish from South American estuaries: risk assessment through consumption

Monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), inorganic arsenic (iAs), and non-toxic species (i.e. arsenobetaine) were determined by HPLC-ICP-MS as mg kg−1 wet weight in muscle, liver and gill of catfish (Genidens barbus) from Argentina (N = 12) and from Brazil (N = 11). Concentrations (mean ± standard deviation) of non-toxic arsenic species were 10.4 ± 2.89 and 14.9 ± 5.94 for muscle, 1.48 ± 0.58 and 2.21 ± 1.24 for liver, and 0.66 ± 0.39 and 2.44 ± 1.93 for gill, respectively, for Argentina and Brazil, and represented 95.5%–99.5% of the total arsenic for each tissue. Toxic arsenic (iAs) levels were 0.048 and 0.013 for muscle, 0.24 and 0.011 for liver, and 0.037 and 0.012 for gill and represented 0.45–4.93 % of the total arsenic for Argentina and 0.24-0.60 % for Brazil. The iAs concentrations for all tissues were below the recommended international and local legislations of 0.1-1.0. Based on iAs in muscle, target hazard quotients were 0.032 and 0.018, respectively, for Argentina and Brazil. Risks of external (skin) cancer and internal (bladder/lung) cancer were 1.4 × 10-5 and 1.9 × 10-4 for Argentina and 7.3 × 10-6 and 9.9 × 10-5 for Brazil, suggesting that populations may be exposed to an internal cancer risk through chronic consumption. Risk assessments need to be based on specific fish and their iAs concentrations in muscle.Fil: Avigliano, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Schlotthauer, Jonatan. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Maichak de Carvalho, Barbara. Universidade Federal do Paraná; BrasilFil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Volpedo, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentin

Distribution of inorganic arsenic species in groundwater from Central-West Part of Santa Fe Province, Argentina

The distribution of inorganic arsenic species in groundwater used as drinking water supply by the peri-urban and rural population from central-western area of Santa Fe Province, Argentina, was studied. An analytical methodology based on an online system of atomic absorption spectrometry with hydride generation and flow injection (FI-HGAAS) was used for total inorganic arsenic determination. For speciation purposes, the distinction between As(V) and As(III) was performed through the on line coupling of FI-HGAAS to a solid phase system based on an anionic exchanger able to retain As(V) as oxyanion, allowing As(III) to be selectively determined. The concentration of As(V) was calculated as the difference between total arsenic and As(III) concentrations. Effects of matrix interference due to the nonselective behavior of the exchange resins were carefully laid. Results for 59 samples collected from 27 localities showed an almost exclusive predominance of pentavalent forms.Fil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Albertengo, Antonella. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Brusa, Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Beldomenico, Horacio Ramon. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Tudino, Mabel Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Analítica. Laboratorio de Análisis Químicos de Trazas; Argentin

Modelling diffusion and adsorption of As species in Fe/GAC adsorbent beds

Background: Arsenic decontamination of drinking water by adsorption is a simple and robust operation. When designing packed bed adsorbers for arsenic, the main problems are the slow diffusion kinetics of As in microporous media and the lack of simple equations for predicting the performance of the equipment. Commercial iron-doped granular activated carbon adsorbents (Fe/GAC) for groundwater arsenic abatement were studied in this work. Basic parameters for arsenate (AsV) adsorption were measured and their performance at larger scale was simulated with an approximate analytical model. Results: In the 0-300 μgAs L-1 range, the AsV adsorption isotherm on Fe/GAC was found to be approximately linear. Assuming Henry's law for adsorption and homogeneous surface diffusion with constant diffusivity for intrapellet mass transfer, an approximate model for flow and adsorption of arsenate inside packed bed adsorbers was developed, and reduced to an analytic compact solution using the quasi-lognormal distribution (Q-LND) approximation. The use of this model with fitted and reported parameters enabled the approximate simulation of industrial adsorbers and home point-of-use filters. Results show that industrial adsorbers meet the breakthrough condition with incomplete utilization of the adsorbent unless convenient process configurations are used. In point-of-use systems with short residence times intraparticle diffusion would drastically reduce the adsorbent performance. Conclusion: Assuming linear adsorption of AsV over Fe/GAC, an analytical approximate solution for flow and adsorption in packed beds can be obtained. The model seems to represent correctly the main features of industrial and home filters, however, more experimental data is necessary for scale-up purposes.Fil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Beldomenico, Horacio Ramon. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Tarifa, Enrique Eduardo. Universidad Nacional de Jujuy. Facultad de Ingeniería; ArgentinaFil: Pieck, Carlos Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Vera, Carlos Roman. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin

Clasificación intra-regional de muestras de miel de Mendoza (Argentina) por medio de análisis multielemental y técnicas de aprendizaje de máquinas

La miel se define como una sustancia dulce naturalmente producida por las abejas Apis Mellifera a partir del néctar de las plantas o de las secreciones de las partes vivas de las plantas. De acuerdo a las estadísticas del 2017 de la FAO (Food and Agriculture Organization)1, Argentina es uno de los mayores productores y exportadores mundiales de miel, ocupando el tercer lugar en cuanto a volumen de la producción y la provincia de Mendoza aporta produciendo mieles de alta calidad. Atendiendo a esto y al hecho de que la concentración de minerales en la miel se correlaciona con orígenes geográficos y florales, se planteó realizar una clasificación de mieles provenientes de tres regiones apícolas de Mendoza (Valle de Uco, Noreste y Sur), en función de su perfil multi-elemental y la aplicación de técnicas quimiométricas de aprendizaje de máquinas.Se determinaron 27 elementos químicos por la técnica ICP-MS en 118 muestras de miel. Encontrándose que Mg, Ca, Na Al, Fe y Zn fueron los elementos mayoritarios (<1 µg/g). El resto de los elementos se obtuvieron en concentraciones menores al microgramo.Para la clasificación geográfica de las mieles se realizó primero un análisis exploratorio con técnicas no supervisadas como PCA y posteriormente un análisis con herramientas de aprendizaje de máquimas como Análisis Discriminante lineal (LDA) y los no lineales, máquina de vectores de soporte (SVM) y bosques aleatórios (RF). Se utilizó un procedimiento llamado validación cruzada para dividir el conjunto de datos en dos partes: entrenamiento (70%) y testing (30%). Se optimizaron los métodos y la mejor tasa de clasificación se obtuvo con el análisis lineal LDA.Fil: Canizo, Brenda Vanina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fiorentini, Emiliano F.. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; ArgentinaFil: Brusa, Lucila. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Pellerano, Roberto Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Química Básica y Aplicada del Nordeste Argentino. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Química Básica y Aplicada del Nordeste Argentino; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaIX Workshop de QuimiometriaNatalBrasilUniversidade Federal do Rio Grande do Norte. Grupo de Pesquisa em Química Biológica e Quimiometri

Comprehensive estimate of the theoretical maximum daily intake of pesticide residues for chronic dietary risk assessment in Argentina

A chronic dietary risk assessment for pesticide residues was conducted for four age groups of the Argentinian population following the procedure recommended by the WHO. The National Theoretical Maximum Daily Intake (NTMDI) for 308 pesticides was calculated for the first time, using the Maximum Residue Limits (MRLs) from several Argentinean regulations and food consumption data from a comprehensive National Nutrition and Health Survey. The risk was estimated by comparing the TMDI with the Acceptable Daily Intakes (ADI) identified by various sources. Furthermore, for each of the compounds with a TMDI >65% of the ADI, a probabilistic analysis was conducted to quantify the probability of exceeding the ADI. In this study 27, 22, 10, and 6 active ingredients (a.i.) were estimated to exceed the 100% of the ADI for the different population groups: 6–23 month-old children, 2–5 year-old children, pregnant women, and 10–49 year-old women, respectively. Some of these ADI-exceeding compounds (carbofuran, diazinon, dichlorvos, dimethoate, oxydemeton-methyl and methyl bromide) were found in all four of these groups. Milk, apples, potatoes, and tomatoes were the foods that contributed most to the intake of these pesticides. The study is of primary importance for the improvement of risk assessment, regulations, and monitoring activities.Fil: Maggioni, Darío Andrés. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Signorini Porchietto, Marcelo Lisandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Michlig, Nicolás. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Repetti, María Rosa. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Beldomenico, Horacio Ramon. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

National short-term dietary exposure assessment of a selected group of pesticides in Argentina

An evaluation of acute dietary exposure to pesticide residues, applying deterministic and stochastic methods, was performed for a selected group of pesticides in two representative age groups from Argentina. Thus, 28 active ingredients (a.i.) and 75 food items were evaluated for the group of 2–5-year-old children, while 9 a.i. and 59 food items were considered for the 10–49-year-old women group. A deterministic assessment was conducting following the Food and Agriculture Organization (FAO) and World Health Organization (WHO) procedure but using the national maximum residue limits (MRLs) as pesticide residue concentration data, while in the stochastic approach, a theoretical distribution modeled with the available information was used. Food consumption data were obtained from the 2004–2005 comprehensive national nutrition and health survey. The risk was estimated by comparing the short-term dietary exposure with the acute reference dose (ARfD) values for each pesticide-food combination evaluated. In the deterministic assessment, 173 (39.1%) and 40 (31.3%) combinations exceeded the ARfD thresholds for the 2–5-year-old children and 10–49-year-old women groups, respectively. This conservative study generated relevant information as a first stage of acute dietary risk assessment in Argentina.Fil: Maggioni, Darío A.. Universidad Nacional del Litoral; ArgentinaFil: Signorini Porchietto, Marcelo Lisandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Michlig, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral; ArgentinaFil: Repetti, María Rosa. Universidad Nacional del Litoral; ArgentinaFil: Sigrist, Mirna Edit. Universidad Nacional del Litoral; ArgentinaFil: Beldomenico, Horacio Ramon. Universidad Nacional del Litoral; Argentin