RESUMEN
Petrochemical facilities, including oil well drilling, are discharging resources of extensive noxious waste into the environment. The workers in different sections might be exposed to vanadium (V) through different routes (groundwater and soil), which is linked with extensive physiological disorders, hypertension, respiratory disorders, anemia, skin, and gastrointestinal disorders. This study determined the contents of V in a biological sample (scalp hair) of workers of different categories (outdoor and office workers) in an oil drilling field in Sindh, Pakistan. The environmental samples, groundwater, bottled mineral water, and soil samples were also analyzed for V. For comparative purposes, the scalp hair of age-matched male subjects residing in domestic areas of Hyderabad city, Pakistan, was also analyzed. Generally, the concentrations of V in groundwater near the oil drilling field and drilled soil illustrated significant variations. The results show that the vanadium concentration in the scalp hair of non-exposed referents (controls) and office workers (exposed referents) was 62% and 45% lower than those observed for outdoor drilling and cleaning mud workers. It was observed that high exposure to V in outdoor workers might be linked with different physiological disorders such as anemia, eye problems, and bronchial disorders.
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BACKGROUND: Breast cancer is an uncommon (rare) disease in men, approximately 1% of the total breast cancer cases in the world. By reason of the rare occurrence, there is no clinical or hospital study giving the information about the essential trace and toxic elements in the biological samples of male breast cancer patients. METHODS: The aim of current study was to estimate association among essential trace {zinc (Zn), iron (Fe) and copper (Cu)} and toxic {cadmium (Cd) and lead (Pb)} elements in human biological samples particularly blood, serum, scalp hair, of male breast cancer patients (n = 14, age range 52 - 58 years) residents of Hyderabad, Pakistan. For comparative purposes, the biological samples of referent persons (n = 37) of the same age groups were also be analyzed. Microwave oven mediated digestion method was employed, and digestion of samples was carried out with the help of 2:1 mixture solution of HNO3 (65%) and H2O2 (30%). Atomic absorption spectrometry was employed for the determination of elemental concentrations from the microwave oven employed digested samples. RESULTS: The found average of essential elements (zinc, iron, and copper) in samples of male breast cancer patients was found to be lower, while cadmium and nickel were found to be higher, when compared with samples from referents (p < 0.001). CONCLUSIONS: These data will be helpful for treatment of male breast cancer patients to improve his health and life.
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Neoplasias de la Mama Masculina , Oligoelementos , Cadmio/análisis , Humanos , Peróxido de Hidrógeno , Masculino , Persona de Mediana Edad , Pakistán , Espectrofotometría Atómica , Oligoelementos/análisis , ZincRESUMEN
It was investigated that toxic metals (cadmium and lead) enhanced in coal gangue soil used for the reclamation of soil, creates adverse impacts on atmosphere. Presently the chemical fractionation of toxic metals in coal, inner and outer coal gangue soil samples of Lakhra coalfield were studied along with the impact on the orchard grass grown on coal gangue soil in a subside land of the coal mining area. The BCR sequential extraction scheme (BCR-SES) was carried out to determine the different chemical profiles of heavy metals in coal and coal gangue soil samples. For comparative purpose time saving conventional single step extraction (CSE) and vortex assisted single step extraction (VSE) schemes based on same working setting used BCR extraction scheme. The all three procedures were validated by a certified soil sample (BCR 483) and standard addition method in real samples. The total Cd and Pb in coal, soil and grass samples were determined prior to oxidize by acid mixture. The separation of each fraction of Cd, and Pb in all types of environmental samples by VSE could be completed in 30-120 s. The extracted Cd and Pb concentrations in reducible fractions by CSE and VSE extraction procedure were 2.5-5% higher than those values gained through BCR-SES. About 71 and 50% of Cd and Pb in coal samples were observed in acid soluble, reducible and oxidizable fraction, respectively, whilst rest of Cd and Pb (29 and 50%) were found in residual phase. The orchard grass (Dactylis glomerata) grown on land reclaimed with OSG was analysed, the bioaccumulate Cd and Pb may create adverse impacts on grazing cattle.
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Monitoreo del Ambiente , Metales Pesados/análisis , Contaminantes del Suelo/análisis , Animales , Cadmio/análisis , Bovinos , Fraccionamiento Químico/métodos , Carbón Mineral/análisis , Minas de Carbón , Dactylis/química , SueloRESUMEN
In present study, the volatilization of arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb) by the burning of coal samples in the electric furnace was evaluated. The coal samples were obtained from different blocks of newly developed Thar coal field, Pakistan. The replicate coal samples were heated/burned in an electric furnace at laboratory scale for three temperature intervals (200, 400 and 900⯰C). The ash obtained after each temperature intervals were analyzed for selected toxic elements. The resulted data indicated that the total contents of As, Cd, and Pb in coal samples of block X and XI were found in the range of 16.8-18.5, 4.21-4.72, and 14.2-18.8â¯mg/kg, respectively. Whereas, 67.8-79.7%, 34.3-36.8% and 9.89-10.8% of As, Cd, and Pb, respectively, were volatized out after combustion of coal samples at 900⯰C. The total contents of Hg in selected coal samples of block X and XI were observed in the range of 0.985-1.46 and 0.992-1.41â¯mg/kg, respectively. The contents of Hg volatilized out via burning in a furnace at 200⯰C and 400⯰C, were observed in the range of 32.0-36.5% and >91.0% of its total contents, respectively, whereas at 900⯰C, it was not detected in ash. The partitioning and mobility of studied toxic elements in residue termed as (laboratory made ash) obtained after burning at 900⯰C, was carried out by three-step sequential extraction scheme. The resulted data of present study will give a better knowledge about the quality of coal and its burning product, which may help to take measure to reduce the adverse effects on the environment in future.
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Ceniza del Carbón/química , Carbón Mineral/toxicidad , Calor , Arsénico/análisis , Cadmio/análisis , Carbón Mineral/análisis , Plomo/análisis , Mercurio/análisis , Pakistán , Medición de Riesgo , VolatilizaciónRESUMEN
The current study was conducted to evaluate the arsenic (As) and fluoride (F-) concentrations in growing media (stored rainwater and soil), of district Tharparkar, Pakistan. The bioaccumulation/transportation of As and F from growing media to different types of vegetables (wild cucumis, Indian squish and cluster bean) was evaluated. Total concentrations of As and F- in stored rainwater samples were observed up to 585 µg/L and 32.4 mg/L, respectively, exceeding many folds higher than WHO provisional guideline values. The As and F- contents in soil samples of nine agricultural sites were found in the range of 121-254 mg/kg and 115-478 mg/kg, respectively. The highest contents of As and F- were observed in wild cucumis as compared to Indian squish and cluster bean (p < 0.05), grown in the same agricultural field. The bioaccumulation factors of As and F- were to be > 4.00, indicating the high rate of transportation of As and F- from growing media to vegetables. A significant positive correlation of As and F- in vegetables with their concentrations in soil and water was observed (r > 0.60 with p < 0.05). The risk assessment elucidated that the population of different age group consuming local vegetables and drinking water contaminated with As and F- may have adverse health effects.
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Arsénico/farmacocinética , Fluoruros/farmacocinética , Contaminación de Alimentos/análisis , Verduras/química , Adolescente , Adulto , Arsénico/análisis , Niño , Fluoruros/análisis , Humanos , Persona de Mediana Edad , Pakistán , Medición de Riesgo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/farmacocinética , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/farmacocinética , Adulto JovenRESUMEN
In present study, the ground water at different aquifers was evaluated for physicochemical parameters, iron, total arsenic, total inorganic arsenic and arsenic species (arsenite and arsenate). The samples of groundwater were collected at different depths, first aquifer (AQ1) 50-60 m, second aquifer (AQ2) 100-120 m, and third aquifer (AQ3) 200-250 m of Thar coalfield, Pakistan. Total inorganic arsenic was determined by solid phase extraction using titanium dioxide as an adsorbent. The arsenite was determined by cloud point extraction using ammonium pyrrolidinedithiocarbamate as a chelating reagent, and resulted complex was extracted by Triton X-114. The resulted data of groundwater were reported in terms of basic statistical parameters, principal component, and cluster analysis. The resulted data indicated that physicochemical parameters of groundwater of different aquifers were exceeded the World Health Organization provisional guideline for drinking water except pH and SO4(2-). The positive correlation was observed between arsenic species and physicochemical parameters of groundwater except F(-) and K(+), which might be caused by geochemical minerals. Results of cluster analysis indicated that groundwater samples of AQ1 was highly contaminated with arsenic species as compared to AQ2 and AQ3 (p > 0.05).
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Arsénico/análisis , Agua Subterránea/análisis , Contaminantes Químicos del Agua/análisis , Adsorción , Agua Potable/análisis , Hierro/análisis , Octoxinol , Pakistán , Polietilenglicoles , Extracción en Fase Sólida , Titanio/química , Calidad del AguaRESUMEN
The aim of the current study is to evaluate the occurrence of arsenic in coal collected from Thar coalfield, Pakistan, and its behavior during the combustion. Fractionation of arsenic (As) in coal samples was carried out by Community Bureau of Reference sequential extraction scheme (BCR-SES) and single-step-based BCR method (BCR-SS). These methods are validated using the certified reference material of sediment BCR 701 and standard addition method. The stepwise fractions of As in laboratory-made ash (LMA) have been also investigated. The extractable As content associated with different phases in coal and LMA samples were analyzed by electrothermal atomic absorption spectrophotometer. The extraction efficiency of As by BCR-SS was slightly higher than BCR-SES, while the difference was not significant (p < 0.05). The BCR-SS method is a time-saving method because it can reduce the extraction time from 51 to 22 h. The As contents in LMA revealed that during combustion of the coal, >85 % of As may be released into atmosphere. The relative mobility of As in the coal samples was found in increasing order as follows: oxidizable fraction < reducible fraction < acid soluble fraction. The total and extractable As obtained by BCR-SES and BCR-SS were higher in coal samples of block III as compared to block V (p > 0.05).
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Arsénico/análisis , Carbón Mineral/análisis , Calor , Fraccionamiento Químico , Minería , Pakistán , Espectrofotometría AtómicaRESUMEN
The aim of present study was to simultaneously estimate the arsenic (As) and fluoride (F(-)) concentrations in irrigated surface water, soil and grain crops of Nagarparkar, Pakistan during 2010-2012. The As and F(-) were analyzed by hydride generation atomic absorption spectrometer and ion selective electrode, respectively. Total arsenic (As(T)) and F(-) in irrigated surface water samples were found in the range of 360-683 µg L(-1) and 18.5-35.4 mg L(-1), respectively. While As(T) and F(-) concentrations in agriculture soil samples were observed in the range of 110-266 and 125-566 mg kg(-1), respectively. The water extractable As and F(-) were found 3-4% of total concentration of these in soils. The As(T) concentration was higher in kidney been (KB) as compared to pearl millet (PM) and green gram (GG), whereas GG had higher F(-) levels as compared to other two grain crops (p<0.05). The KB samples grown in nine sites shows BCF of As in the range of 0.018-0.038. The GG has higher BCF of F(-) as compared to KB and PM (p<0.05) grown in all sites. The exposure dose and risk factor of As and F(-) were obtained by estimated daily intake (EDI) and hazardous index (HI). It was found that all understudy age groups were at the severe risk of arsenicosis and fluorosis, but the severity is higher in younger age group (7-15 years) as compared to elder groups (p<0.05).
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Arsénico/análisis , Grano Comestible/química , Exposición a Riesgos Ambientales/análisis , Contaminantes Ambientales/análisis , Fluoruros/análisis , Agua/química , Adolescente , Adulto , Niño , Análisis por Conglomerados , Recolección de Datos , Ingestión de Líquidos , Humanos , Persona de Mediana Edad , Pakistán , Suelo/química , Adulto JovenRESUMEN
A method has been developed for the determination of arsenic (As) in pharmaceutical and scalp hair samples of kidney failure patients by cloud point extraction (CPE). The scalp hair samples were subjected to microwave-assisted digestion in nitric acid-hydrogen peroxide (2 + 1, v/v). Then, dialysate and digested scalp hair solutions were preconcentrated by CPE using pyronine B as a complexing agent. The resulting complex was entrapped in nonionic surfactant (Triton X-114) prior to its determination by electrothermal atomic absorption spectroscopy. The validity of the CPE method for As was checked by analysis of a certified reference material of human hair and a standard addition method for dialysate solution. The chemical variables affecting the analytical performance of the CPE methods were studied and optimized. After optimization of the complexation and extraction conditions, a preconcentration factor of 52 was obtained for As in 10 mL of dialysate solution and acid digested samples of scalp hair. Under the optimum experimental conditions, the LOD and LOQ of As for the preconcentration of 10 mL of solution were 0.022 and 0.073 microg/L, respectively. The level of As in scalp hair samples of kidney failure patients was higher than in healthy controls.
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Arsénico/análisis , Soluciones para Diálisis/análisis , Cabello/química , Insuficiencia Renal/metabolismo , Cuero Cabelludo/química , Adulto , Algoritmos , Femenino , Humanos , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Límite de Detección , Masculino , Octoxinol , Polietilenglicoles/química , Pironina/análogos & derivados , Pironina/química , Espectrofotometría Atómica , Tensoactivos , Abastecimiento de Agua/análisisRESUMEN
The aim of this study was to evaluate the translocation of arsenic (As) by different vegetables grown in agricultural soil irrigated for long period with tube well water as test vegetable samples and compared those vegetables of same species grown in agricultural soil irrigated with fresh canal water marked as control vegetable samples. Moreover, the total and ethylene-diamine-tetra acetic acid (EDTA) extractable contents of As in soil irrigated by tube well and canal water were determined and correlate with total concentrations of As in edible parts of vegetables. Statistically significant correlations were obtained between the total and EDTA extractable fractions of As in soil. High level of total and EDTA extractable As were found in tested vegetable samples as compared to controlled vegetable samples. This investigation highlights the increased danger of growing vegetables in the agricultural land continuously irrigated by As contaminated water.
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Arsénico/metabolismo , Contaminantes del Suelo/metabolismo , Suelo/química , Verduras/metabolismo , Arsénico/análisis , Ácido Edético/metabolismo , Contaminación Ambiental , Contaminantes del Suelo/análisisRESUMEN
Advanced extraction methods have been developed for direct speciation of dissolved inorganic and organic selenium (Se) species in aqueous extracts of medicinal plants (MPs). The inorganic species of Se (SeIV and SeVI) were separated from organic forms by adsorbing inorganic Se on alumina, while the organic Se was not retained. The retained inorganic Se species was eluted with 10 mL 0.2 M HCl. The total inorganic Se species was determined after prereduction of SeVI into SeIV with concentrated HCl. The SeIV in the eluent and total inorganic Se species were then complexed with diethyldithiocarbamate. The resultant complexes were entrapped in the nonionic surfactant Triton X-114. The total Se, organic Se, total inorganic Se, and SeIV species were determined by electrothermal atomic absorption spectrometry with a modifier. The SeVI concentration was obtained by subtracting SeIV from total inorganic Se contents. The main factors affecting the methodologies were investigated in detail. Under the optimized experimental conditions, the LOD for SeIV was 50 microg/L. Among dissolved inorganic and organic Se species in aqueous extracts of MPs, organic Se species were present in the range of 74-84%, SeIV 3.62-7.47%, and SeVI 12.4-18.57% of total Se contents.
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Extractos Vegetales/química , Plantas Medicinales/química , Selenio/análisis , Agua/química , Concentración de Iones de HidrógenoRESUMEN
The antagonistic effects between selenium (Se) and arsenic (As) suggest that low Se status plays an important role in arsenism development. The objective of present study was to assess Se contents in biological samples of As exposed females have skin lesions and cancer with related to non-exposed skin cancer patients. The biological samples (blood and scalp hair) of As exposed group comprises, female skin cancer (ESC) patients admitted in cancer hospitals have skin lesions (ESL) and exposed referents have not both diseases (ER), belongs to As exposed area of Pakistan. For comparative purposes, age matched female skin cancerous patient (RP) and non-cancerous females (NER) belong to non-exposed areas were also selected. The As and Se in acid digests of biological samples were pre-concentrated by complexing with chelating agent (ammonium pyrrolidinedithiocarbamate), and resulted complexes were extracted into non-ionic extractant (Triton X-114), prior to analysis by electrothermal atomic absorption spectrometry. The enhancement factor of about 25 was obtained by pre-concentrating 10 mL of sample solutions. The accuracy of the optimized procedure was evaluated by using certified reference material (BCR 397) with certified values for Se and As and standard addition method at three concentration levels in real samples. No significant differences was observed (p>0.05) when comparing the values obtained by the proposed method, added and certified values of both elements. The biological samples of ESC patients had 2-3 folds higher As and lower Se levels as compared to RP (p<0.001). Understudied exposed referents have high level of As and lower Se contents as compared to referents subjects of non-exposed area (p<0.01). The higher concentration of As and lower levels of Se in biological samples of cancerous patients are consisted with reported studies.
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Arsénico/toxicidad , Contaminantes Ambientales/toxicidad , Selenio/metabolismo , Neoplasias Cutáneas/metabolismo , Piel/metabolismo , Adulto , Arsénico/análisis , Arsénico/metabolismo , Exposición a Riesgos Ambientales/análisis , Exposición a Riesgos Ambientales/estadística & datos numéricos , Contaminantes Ambientales/análisis , Contaminantes Ambientales/metabolismo , Femenino , Humanos , Persona de Mediana Edad , Piel/patología , Neoplasias Cutáneas/epidemiología , Abastecimiento de Agua/análisisRESUMEN
A method has been developed for speciation of total, total inorganic and organic arsenic (As) species in groundwater samples. The inorganic species of As((III,V)) were separated from organic forms by adsorbing on alumina (Al(2)O(3)) whereas the organic As was eluted out. The retained inorganic As species was eluted by 0.2 M HCl. Then eluent As(III) and As(V) were formed as complexes with ammonium pyrrolidinedithiocarbamate (APDC) and molybdate, respectively. Then As(III)-PDC and As(V)-molybdate complexes were quantitatively extracted into a non-ionic surfactant Triton X-114. The total As was determined by conventional preconcentration procedures. The resulting solutions of each method were determined by ETAAS with modifier. The main factors affecting the separation and cloud point extraction (CPE) were investigated in detail. The limits of detection values were found as 0.04 and 0.20 µg L(-1) for As(III) and As(V), respectively, whereas limits of quantification were observed as 0.13 and 0.33 µg L(-1) for As(III) and As(V), respectively. Standard addition method confirmed the accuracy. The recoveries of As(III) and As(V) were found in the range of 98 - 99%. The proposed method was applied to groundwater samples collected from different areas of Sukkur district.
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This study was focused on the analysis of arsenic (As) levels in scalp hair of children (age, <10 years) collected from two towns of Khairpur, Pakistan, to evaluate the effects of As-contaminated groundwater. For comparative purposes, scalp hair samples of children were also collected from that area having low levels of As (<10 µg/L) in drinking water. Groundwater and scalp hair samples of children were collected and analyzed by electrothermal atomic absorption spectrometry prior to microwave-assisted acid digestion. The average As concentrations in groundwater samples of two towns, Thari Mirwah and Gambat, were found to be 28.5 and 98.3 µg/L, respectively. The range of As concentrations in scalp hair samples of children who belong to Thari Mirwah and Gambat was 1.25-1.61 µg/g and 1.73-3.63 µg/g, respectively. Twenty percent of the total children who belong to Gambat have skin lesions on their hands and feet. A positive correlation coefficient (R = 0.91-0.99) was obtained between As contents in drinking water and scalp hairs of children of both towns.
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Arsénico/análisis , Arsénico/metabolismo , Agua Potable/análisis , Cabello/metabolismo , Cuero Cabelludo/metabolismo , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Pakistán , Espectrofotometría AtómicaRESUMEN
The aim of this study was to evaluate the uptake of arsenic (As) by grain crops (wheat, maize and sorghum) grown on agricultural soil irrigated with tube well water (SIT) as test samples and for comparative purposes, same grain crop samples grown on agricultural soil irrigated with fresh canal water (SIC) were marked as control samples, collected simultaneously from three sub-districts of Khairpur, Pakistan. Moreover, this paper demonstrated the total and EDTA (0.05 M) extractable As in both understudied soils that correlate with the respective total As in the edible parts of the studied grain crops. A significantly high accumulation of As was found in grains grown on SIT as compared to those grown on SIC. This study highlights the increased danger of growing food crops in the agricultural land continuously irrigated by As contaminated ground water.
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Riego Agrícola , Arsénico/análisis , Productos Agrícolas/química , Grano Comestible/química , Contaminantes del Suelo/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
A simple and rapid cloud point extraction method was applied for preconcentration of trace quantities of zinc (Zn) and iron (Fe) in biological samples (serum and urine) of thyroid patients prior to determination by flame atomic absorption spectrometry. The metals in serum and urine samples were complexed with 1-(2-thiazolylazo)-2-naphthol and entrapped in the surfactant octylphenoxypolyethoxyethanol (Triton X-114). After centrifugation, the surfactant-rich phase was diluted with 0.1 M HNO3 in methanol. For optimum recovery of analytes, the influences of the analytical parameters, including pH and amounts of complexing and surfactant reagents, were investigated. Enrichment factors of 66.4 and 70.2 were obtained for the preconcentration of Zn(II) and Fe(III), respectively. The obtained results showed sufficient recoveries (>98%) for Zn(II) and Fe(III) in certified reference materials (CRMs). The proposed method was applied to the determination of Zn(II) and Fe(III) in biological (serum and urine) samples and CRMs.
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Bocio/metabolismo , Hierro/análisis , Espectrofotometría Atómica/métodos , Zinc/análisis , Adulto , Calibración , Estudios Transversales , Humanos , Concentración de Iones de Hidrógeno , Hierro/sangre , Hierro/orina , Masculino , Persona de Mediana Edad , Octoxinol , Polietilenglicoles/química , Temperatura , Zinc/sangre , Zinc/orinaRESUMEN
A cloud point extraction (CPE) method has been developed for the determination of trace quantity of vanadium ions in pharmaceutical formulations (PF), dialysate (DS) and parenteral solutions (PS). The CPE of vanadium (V) using 8-hydroxyquinoline (oxine) as complexing reagent and mediated by nonionic surfactant (Triton X-114) was investigated. The parameters that affect the extraction efficiency of CPE, such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validity of CPE of V was checked by standard addition method in real samples. The extracted surfactant-rich phase was diluted with nitric acid in ethanol, prior to subjecting electrothermal atomic absorption spectrometry. Under these conditions, the preconcentration of 50 mL sample solutions, allowed raising an enrichment factor of 125-fold. The lower limit of detection obtained under the optimal conditions was 42 ng/L. The proposed method has been successfully applied to the determination of trace quantity of V in various pharmaceutical preparations with satisfactory results. The concentration ranges of V in PF, DS and PS samples were found in the range of 10.5-15.2, 0.65-1.32 and 1.76-6.93 microg/L, respectively.
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Oxiquinolina/química , Soluciones para Nutrición Parenteral/química , Preparaciones Farmacéuticas/química , Tensoactivos/química , Vanadio/aislamiento & purificación , Calibración , Centrifugación , Diálisis , Concentración de Iones de Hidrógeno , Soluciones , Espectrofotometría Atómica , TemperaturaRESUMEN
In present study a biomass derived from the stem of Acacia nilotica has been investigated to remove As ions from surface water samples of different origins (lake, canal and river). The effects of various parameters viz. pH, biosorbent dosage, contact time and temperature on the biosorption processes were systematically studied. Experimental data were modeled by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. It was observed that As biosorption best fitted to the Langmuir and Freundlich isotherms. The mean sorption energy (E) calculated from D-R model, indicated physico-chemical biosorption. Study of thermodynamic parameters revealed the endothermic, spontaneous and feasible nature of biosorption process. The pseudo-second-order rate equation described better the kinetics of As biosorption with good correlation coefficients than pseudo-first-order equation. The biomass of A. nilotica was found to be effective for the removal of As with 95% sorption efficiency at a concentration of <200 microg/L of As solution, and thus uptake capacity is 50.8 mg As/g of biomass. The A. nilotica biomass could be used as a low-cost biosorbent for As ion removal.
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Acacia/química , Arsénico/aislamiento & purificación , Purificación del Agua/métodos , Abastecimiento de Agua/análisis , Adsorción , Algoritmos , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Cinética , Microscopía Electrónica de Rastreo , Tallos de la Planta/química , Polvos , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura , TermodinámicaRESUMEN
A simple and rapid ultrasound-assisted extraction procedure was developed for the determination of total mercury (Hg) in muscle tissues of freshwater fish species. A Plackett-Burman experimental design was used as a multivariate strategy for the evaluation of the effects of variables, such as presonication time (without ultrasonic stirring), sonication time, ultrasonic bath temperature, nitric acid concentration, hydrochloric acid concentration, and sample mass of muscle tissues. Some variables showed a significant effect on recovery, and they were further optimized by a 2(3) + star central composite design that involved 16 experiments. The validation was carried out by analysis of certified reference material DORM-2 (dog fish muscles); for comparative purposes, an acid digestion induced by microwave energy was used. Cold vapor atomic absorption spectrometry was used for the determination of total Hg. No significant differences were established between the analytical results and the certified values (paired t-test at P > 0.05). The LOD and LOQ of Hg were 0.133 and 0.445 microg/kg, respectively, which demonstrated the high sensitivity of the proposed procedure for the determination of Hg at trace levels. The Hg concentrations in the muscle tissues of 10 freshwater fish species were found in the range of 35.3-67.8 microg/kg on a dried basis, which were within the permissible limit of the World Health Organization.