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1.
Opt Express ; 29(6): 8490-8497, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33820295

RESUMEN

Metal nanomaterials have been widely used to generate photoacoustic (PA) signals because of their high optical absorption characteristics. However, the PA conversion efficiency of metal nanomaterials is limited by the single-wavelength absorption at the resonant peak. To mitigate this issue, a three-layer ultrathin film containing a thin PDMS layer sandwiched between two ultrathin chromium films is proposed. This kind of film structure can attain high optical absorbance (>80%) through the visible light range (450-850 nm). The optical absorption characteristics can be easily modulated by varying the thickness of the PDMS layer. Under the same excitation condition, the PA signal generated by this film structure is twice that of an only Cr film and three times that of an only Au film. This film structure is easily fabricated and can operate with lasers having different central wavelengths or even white light sources, leading to its applications in many fields, including photoacoustic communications and audio transducers.

2.
Opt Express ; 27(5): 7277-7290, 2019 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-30876294

RESUMEN

In this research work we demonstrated negative axicon optical fiber tip filled with Polydimethylsiloxane (PDMS) as a sensor platform for volatile organic gases detection at room temperature. The response of the sensor was measured with various Volatile Organic Compounds (VOCs) such as Chloroform, Hexane, Isopropanol, Acetone, Toluene and Methanol in the concentration ranging from 5 to 200 ppm. The corresponding sensitivity and limit of detection (LOD) of the developed sensor for the measured VOCs were observed between the order of around 23.7 to 3.2 pm/ppm and 0.84 to 6.10 ppm, respectively. The response and recovery time of sensor were found between the order of 30 to 57 seconds and 8 to 25 seconds respectively for the measured VOCs. Thermal stability of the developed sensor was also studied at 30-70 °C with intervals of 10°C. The principle of sensing is based on change in the length of the Fabry-Perot Interferometric (FPI) cavity in the presence of varied concentrations of VOCs, which results in changes in the shift in wavelength of an interference pattern attributed to the change in PDMS filling the cavity length (swelling). The experimentally observed trends in the relative swelling of PDMS with VOCs are found in agreement with the theoretically calculated values obtained from the Hansen solubility parameter (HSP). The developed gas sensor has the potential to fulfill the demands of industrial applications.

3.
Antimicrob Agents Chemother ; 60(5): 2972-80, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-26953207

RESUMEN

To determine the distribution and relationship of antimicrobial resistance determinants among extended-spectrum-cephalosporin (ESC)-resistant or carbapenem-resistant Escherichia coli isolates from the aquatic environment in India, water samples were collected from rivers or sewage treatment plants in five Indian states. A total of 446 E. coli isolates were randomly obtained. Resistance to ESC and/or carbapenem was observed in 169 (37.9%) E. coli isolates, which were further analyzed. These isolates showed resistance to numerous antimicrobials; more than half of the isolates exhibited resistance to eight or more antimicrobials. The blaNDM gene was detected in 14/21 carbapenem-resistant E. coli isolates: blaNDM-1 in 2 isolates, blaNDM-5 in 7 isolates, and blaNDM-7 in 5 isolates. The blaCTX-M gene was detected in 112 isolates (66.3%): blaCTX-M-15 in 108 isolates and blaCTX-M-55 in 4 isolates. We extracted 49 plasmids from selected isolates, and their whole-genome sequences were determined. Fifty resistance genes were detected, and 11 different combinations of replicon types were observed among the 49 plasmids. The network analysis results suggested that the plasmids sharing replicon types tended to form a community, which is based on the predicted gene similarity among the plasmids. Four communities each containing from 4 to 17 plasmids were observed. Three of the four communities contained plasmids detected in different Indian states, suggesting that the interstate dissemination of ancestor plasmids has already occurred. Comparison of the DNA sequences of the blaNDM-positive plasmids detected in this study with known sequences of related plasmids suggested that various mutation events facilitated the evolution of the plasmids and that plasmids with similar genetic backgrounds have widely disseminated in India.


Asunto(s)
Antibacterianos/farmacología , Carbapenémicos/farmacología , Cefalosporinas/farmacología , Escherichia coli/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple/genética , Escherichia coli/metabolismo , India , Pruebas de Sensibilidad Microbiana , Plásmidos/genética , Ríos/microbiología , Aguas del Alcantarillado/microbiología , Purificación del Agua
4.
Environ Sci Technol ; 50(1): 428-34, 2016 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-26629709

RESUMEN

Synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), are extensively used in food, cosmetic and plastic industries. Nevertheless, limited information is available on human exposures, other than the dietary sources, to SPAs. In this study, occurrence of 9 SPAs and their metabolites/degradation products was determined in 339 indoor dust collected from 12 countries. BHT was found in 99.5% of indoor dust samples from homes and microenvironments at concentrations that ranged from < LOQ to 118 µg/g and 0.10 to 3460 µg/g, respectively. This is the first study to measure BHT metabolites in house dust (0.01-35.1 µg/g) and their concentrations accounted for 9.2-58% of the sum concentrations (∑SPAs). 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO), 2,6-di-tert-butyl-4-(hydroxymethyl)phenol (BHT-OH), 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q) were the major derivatives of BHT found in dust samples. The concentrations of gallic acid esters (gallates) in dust from homes and microenvironments ranged from < LOQ to 18.2 and < LOQ to 684 µg/g, respectively. The concentrations and profiles of SPAs varied among countries and microenvironments. Significantly elevated concentrations of SPAs were found in dust from an e-waste workshop (1530 µg/g). The estimated daily intake (EDI) of BHT via house dust ingestion ranged from 0.40 to 222 ng/kg/d (95th percentile).


Asunto(s)
Antioxidantes/análisis , Polvo/análisis , Contaminantes Ambientales/análisis , Fenoles/análisis , Benzaldehídos/análisis , Hidroxitolueno Butilado/análogos & derivados , Hidroxitolueno Butilado/análisis , Ácido Gálico/análisis , Características de la Residencia
5.
Ambio ; 43(8): 1029-46, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24924188

RESUMEN

Ganges River dolphin, Platanista gangetica gangetica, is one of the three obligatory freshwater dolphins in the world and is distributed in the Ganges-Brahmaputra-Meghna and Sangu-Karnaphuli River systems in India, Nepal, and Bangladesh. This species is facing considerable threats to its survival, and its population has dwindled from 4000 to 5000 in the early 1980s to 3500 in 2014 in the distribution range. This article reviews current status of the sub-species, habitat use, and the potential threats that the dolphins face for their survival (details of taxonomic status and genetics, evolutionary adaptations and anatomical peculiarities, physical adaptation, primitive characteristics, biology, behavior, surfacing behavior and dive times, mating and birth, and life span/age have been placed as Electronic Supplementary Materials). Recommendations have been made for the protection and developing strategies for the conservation of this Endangered and endemic sub-species.


Asunto(s)
Conservación de los Recursos Naturales , Delfines/fisiología , Ríos , Animales , Especies en Peligro de Extinción , India , Densidad de Población , Contaminantes Químicos del Agua
6.
Environ Sci Technol ; 44(18): 7043-9, 2010 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-20795671

RESUMEN

The widespread distribution of perfluorinated chemicals (PFCs) in different environmental matrices has prompted concern about the sources, fate, and transport of these classes of chemicals. PFCs are present in the atmosphere, but only a few studies have investigated their occurrence in precipitation. In this study, concentrations of 20 PFCs, including C3-C5 short-chain PFCs, were quantified using HPLC-MS/MS in precipitation samples from Japan (n = 31), the United States (n = 12), China (n = 5), India (n = 2), and France (n = 2). Among the PFCs measured, perfluoropropanoic acid (PFPrA) was detected in all of the precipitation samples. Average total PFC concentrations ranged from 1.40 to 18.1 ng/L for the seven cities studied. The greatest total PFC concentrations were detected in Tsukuba, Japan, whereas the lowest concentrations were detected in Patna, India. PFPrA, perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were found to be the dominant PFCs in Japanese and U.S. precipitation samples. No observable seasonal trend was found in precipitation samples from two locations in Japan. Annual fluxes of PFCs were estimated for Japan and the U.S. and the evidence for precipitation as an effective scavenger of PFCs in the atmosphere is reported.


Asunto(s)
Fluorocarburos/química , Lluvia/química , Atmósfera/química , China , Francia , India , Internacionalidad , Japón , Estaciones del Año , Estados Unidos
7.
Nanomedicine (Lond) ; 14(14): 1841-1855, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31267842

RESUMEN

Aim: Blood perfusion-based requirement of nanoparticle dose-loadings is computed for plasmonic photothermal therapy of a tumor. Methods: Thermal damage is quantified through coupled multiphysics approach to specify nanoparticle loadings. Results: For low blood perfusion, the nanoparticle loading of 1 mm at 0.02 mg/ml or 3 mm at 0.2 mg/ml concentration may be chosen depending upon the desired tumor margins. For high blood perfusion, nanoparticle loading of 3 mm at 0.2 mg/ml concentration with irradiation parameters of 1 W/cm2 and 200 s seems desirable. Conclusion: Lower nanoparticle loadings within deeper periphery of tumor damage the deeper healthy tissue. If tumor margin is not to be ablated, then higher nanoparticle loadings should be opted instead of higher irradiation duration.


Asunto(s)
Hipertermia Inducida/métodos , Nanopartículas/uso terapéutico , Neoplasias/terapia , Velocidad del Flujo Sanguíneo , Humanos , Nanomedicina/métodos , Nanopartículas/administración & dosificación , Neoplasias/irrigación sanguínea
8.
Sci Rep ; 9(1): 6987, 2019 05 06.
Artículo en Inglés | MEDLINE | ID: mdl-31061441

RESUMEN

The present study reports an alternative method of functionalizing the optical fiber Surface Plasmon Resonance (SPR) sensing probe with antibodies for label-free detection of bovine serum albumin (BSA) protein. In this novel approach, the gold coated fiber was first modified with Molybdenum disulfide (MoS2) nanosheets followed by its bio-functionalization with Anti-BSA antibodies. The developed technique not only allowed the amplification of the SPR signals by synergic effects of MoS2 and gold metallic thin film but also enabled a direct and chemical-free attachment of representative antibodies through hydrophobic interactions. The sensitivity of the MoS2 modified sensing probe with detection limit of 0.29 µg/mL was improved as compared to the fiber optic SPR biosensor without MoS2 overlayer (Detection limit  for BSA was 0.45 µg/mL). The developed biosensor has good specificity, and environmental stability. Accordingly, the proposed design of the MoS2 based SPR optical biosensor can offer the development of a simplified optical device for the monitoring of various biomedical and environmental parameters.


Asunto(s)
Técnicas Biosensibles/instrumentación , Tecnología de Fibra Óptica/instrumentación , Nanoestructuras/química , Albúmina Sérica Bovina/análisis , Resonancia por Plasmón de Superficie/métodos , Animales , Anticuerpos Monoclonales/química , Bovinos , Disulfuros/química , Fluoresceína-5-Isotiocianato/química , Colorantes Fluorescentes/química , Oro/química , Interacciones Hidrofóbicas e Hidrofílicas , Límite de Detección , Molibdeno/química , Fibras Ópticas , Soluciones
9.
Rev Sci Instrum ; 90(2): 025003, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30831695

RESUMEN

An optical fiber based immunosensing platform formed by two identical chirped long period gratings (CLPGs) for sensitive and label-free detection of Escherichia coli (E. coli) is presented. The proposed immunosensor having two CLPGs with an inter-grating space (IGS) works like a Mach-Zehnder interferometer. The important feature of this sensor is that by changing the refractive index (RI) induced phase at the IGS region, a corresponding shift in resonance wavelength can be realized without affecting the actual grating region. Additionally, the confining bandwidth of the interference fringes promotes greater resolution in the resonance wavelength analysis of the transmission spectrum. The main aim of this study was the specific and rapid detection of the E. coli bacteria in phosphate buffer saline (detection range: 10 cfu/ml to 60 cfu/ml) by using the bio-functionalized IGS region as a sensing probe of the dual CLPG structure. The observed detection limit was 7 cfu/ml. For specificity analysis, Salmonella typhimurium and Staphylococcus aureus were tested and no significant shift in resonance wavelength was observed. In addition, the proposed immunosensor has the ability to selectively detect E. coli in real samples including lake water. The high specificity, good sensitivity to ambient RI, and robustness of the developed sensing platform will open a new avenue in optical immunosensing technology, and cascaded long CLPG sensors can contribute significantly to the detection of pathogenic bacteria in water and food samples.


Asunto(s)
Escherichia coli/aislamiento & purificación , Inmunoensayo/instrumentación , Anticuerpos Inmovilizados/química , Anticuerpos Inmovilizados/inmunología , Escherichia coli/inmunología
10.
Biosens Bioelectron ; 126: 501-509, 2019 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-30476881

RESUMEN

The molybdenum disulfide (MoS2) nanosheets functionalized fiber optic surface plasmon resonance (SPR) immunosensor has been reported for the sensitive detection of Escherichia coli (E. coli). The MoS2 nanosheets were prepared by chemical exfoliation method. The synthesised nanostructures were characterized for their structural, morphological and optical properties. The E. coli monoclonal antibodies were successfully immobilized on the MoS2 functionalized sensing platform via hydrophobic interactions. An alternative method simplifying the antibodies immobilization process by functionalization of 2D nanomaterial (MoS2 nanosheets) for rapid (~15 mins) bacterial quantification is presented in this study. The immunosensor uses wavelength interrogation method and a strong linear relationship (R2 = 0.994) was observed between spectral response of immunosensor and different concentration of E. coli. The nonspecificity and cross-reactivity studies of the developed immunosensor were investigated with detection of Salmonella Typhimurium and Staphylococcus aureus. To demonstrate the practical application, spiked samples of water and orange juice were analysed with acceptable recovery results. The label-free immunosensor exhibits better performance, detection limit (94 CFU/mL), high sensitivity (2.9 nm/1000 CFU mL-1; 3135 nm/RIU) and profound specificity as compared to conventional fiber optic SPR sensor (detection limit: 391 CFU/mL, sensitivity: 0.6 nm/1000 CFU mL-1; 1646 nm/RIU). This sensing platform shows promising applications in regular water and food quality monitoring for various pathogenic microorganisms.


Asunto(s)
Anticuerpos Inmovilizados/química , Técnicas Biosensibles , Escherichia coli/aislamiento & purificación , Nanoestructuras/química , Disulfuros/química , Escherichia coli/inmunología , Escherichia coli/patogenicidad , Tecnología de Fibra Óptica , Límite de Detección , Molibdeno/química , Resonancia por Plasmón de Superficie
11.
Environ Int ; 133(Pt A): 105178, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31648162

RESUMEN

A total of 20 organophosphate triesters (OPEs), including seven alkyl-OPEs, three chlorinated (Cl)-OPEs, seven aryl-OPEs, and three oligomeric-OPEs were measured in 341 house dust samples collected from 12 countries during the period 2010-2014. OPEs were ubiquitous in indoor dust, and the total concentrations of OPEs (∑OPEs; sum of 20 OPEs) ranged from 49.4 to 249,000 ng/g dry weight (dw). Generally, Cl-OPEs were the predominant compounds (51% of total) in indoor dust samples, with a median concentration of 800 ng/g, followed by alkyl-OPEs (31%), aryl-OPEs (17%), and oligomeric-OPEs (1%), with median concentrations of 480, 270, and 21.9 ng/g, respectively. ∑OPE concentrations in indoor dust from more industrialized countries (South Korea: median, 31,300; Japan: 29,800; and the United States: 26,500 ng/g dw) were one or two orders of magnitude higher than those from less industrialized countries (Greece: 7140, Saudi Arabia: 5310, Kuwait: 4420, Romania: 4110, Vietnam: 1190, China: 1120, Colombia: 374, India: 276, and Pakistan: 138 ng/g dw). Statistically significant positive correlations (0.114 < r < 0.748, p < 0.05) were found among the concentrations of 16 OPEs in dust samples, indicating similar sources of these compounds. The median estimated daily intakes of ΣOPEs via dust ingestion for children and adults were in the ranges of 0.29-64.8 and 0.07-14.9 ng/kg bw/day, respectively.


Asunto(s)
Contaminación del Aire Interior/análisis , Polvo/análisis , Exposición a Riesgos Ambientales , Ésteres/análisis , Organofosfatos/análisis , Ingestión de Alimentos , Humanos
12.
Sci Total Environ ; 593-594: 592-598, 2017 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-28360009

RESUMEN

Parabens (p-hydroxy benzoic acid esters) are antimicrobial agents, used widely as preservatives in personal care products (PCPs), pharmaceuticals, foods, and beverages. PCPs that contain parabens are a major source of these chemicals in sewage treatment plants (STPs). Very few studies have demonstrated the occurrence of parabens in wastewater. In this study, the occurrence and fate of six parabens, methyl-(MeP), ethyl-(EtP), propyl-(PrP), butyl-(BuP), hepty-(HpP) and benzyl-(BzP) parabens, and five of their metabolites (4-HB, 3,4-DHB, OH-MeP, OH-EtP and BA) were studied in five STPs in India. The concentrations of parent parabens (∑6parent parabens) in five STPs ranged between 131 and 920ng/L in influent; 16 and 67ng/L in effluent; and 104 and 1090ng/g, dry weight, in sludge samples. The sum concentrations of five paraben metabolites (∑5paraben metabolites) in five STPs ranged between 4110 and 34,600ng/L in influent; 2560 and 3800ng/L in effluent; and 1220 and 35,900ng/g, dry weight, in sludge samples. These values were higher than those reported for many industrialized countries. We calculated the mass loadings, removal efficiencies, and environmental emissions of parabens based on the measured concentrations in influents, effluents, and sludge. The mean removal efficiencies of parent parabens and their metabolites ranged from 80% to 100% and 28% to 76%, respectively.

13.
Opt Express ; 14(22): 10790-4, 2006 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-19529489

RESUMEN

A new design of optical waveguide polarizer based on photonic band gap has been presented. A numerical approach based on the finite difference time domain method has been used to analyze and design photonic band gap polarizer. The performance of the device is investigated in terms of degree of polarization and transmittance. Polarizer action is achieved by engineering the defect modes in photonic band gap structures.

14.
Proc Inst Mech Eng H ; 230(6): 553-60, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27006421

RESUMEN

This article evaluates the effect of stress variation on adult femur following total hip replacement using musculoskeletal-based finite element analysis. The aim was to study the changes in stress distribution in the femur after total hip replacement by providing simulated in vivo loading and boundary conditions. The loading and boundary conditions were generated using a musculoskeletal modelling software 'AnyBody' and were applied on femur model, generated from the computed tomography (CT) scan data for standing posture of male patient. The results showed considerable variation in stress distribution pattern in the femur before and after total hip replacement, the metallic implant taking major loads of human body and transferring very less loads to the femur.


Asunto(s)
Artroplastia de Reemplazo de Cadera , Fémur/fisiopatología , Fenómenos Biomecánicos , Simulación por Computador , Fémur/diagnóstico por imagen , Prótesis de Cadera , Humanos , Imagenología Tridimensional , Masculino , Persona de Mediana Edad , Modelos Anatómicos , Sistema Musculoesquelético/fisiopatología , Estrés Mecánico , Tomografía Computarizada por Rayos X , Soporte de Peso
15.
Environ Int ; 83: 183-91, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26177148

RESUMEN

Tetrabromobisphenol A (TBBPA) and eight bisphenol analogues (BPs) including bisphenol A (BPA) were determined in 388 indoor (including homes and microenvironments) dust samples collected from 12 countries (China, Colombia, Greece, India, Japan, Kuwait, Pakistan, Romania, Saudi Arabia, South Korea, U.S., and Vietnam). The concentrations of TBBPA and sum of eight bisphenols (Æ©BPs) in dust samples ranged from <1 to 3600 and from 13 to 110,000 ng/g, respectively. The highest TBBPA concentrations in house dust were found in samples from Japan (median: 140 ng/g), followed by South Korea (84 ng/g) and China (23 ng/g). The highest ∑BPs concentrations were found in Greece (median: 3900 ng/g), Japan (2600 ng/g) and the U.S. (2200 ng/g). Significant variations in BPA concentrations were found in dust samples collected from various microenvironments in offices and homes. Concentrations of TBBPA in house dust were significantly correlated with BPA and ∑BPs. Among the nine target chemicals analyzed, BPA was the predominant compound in dust from all countries. The proportion of TBBPA in sum concentrations of nine phenolic compounds analyzed in this study was the highest in dust samples from China (27%) and the lowest in Greece (0.41%). The median estimated daily intake (EDI) of ∑BPs through dust ingestion was the highest in Greece (1.6-17 ng/kg bw/day), Japan (1.3-16) and the U.S. (0.89-9.6) for various age groups. Nevertheless, in comparison with the reported BPA exposure doses through diet, dust ingestion accounted for less than 10% of the total exposure doses in China and the U.S. For TBBPA, the EDI for infants and toddlers ranged from 0.01 to 3.4 ng/kg bw/day, and dust ingestion is an important pathway for exposure accounting for 3.8-35% (median) of exposure doses in China.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Polvo/análisis , Exposición a Riesgos Ambientales , Contaminantes Ambientales/análisis , Bifenilos Polibrominados/análisis , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Compuestos de Bencidrilo/análisis , Niño , Preescolar , Monitoreo del Ambiente , Humanos , Lactante , Recién Nacido , Persona de Mediana Edad , Fenoles/análisis , Adulto Joven
16.
Environ Int ; 78: 39-44, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25749636

RESUMEN

Siloxanes are used widely in a variety of consumer products, including cosmetics, personal care products, medical and electrical devices, cookware, and building materials. Nevertheless, little is known on the occurrence of siloxanes in indoor dust. In this survey, five cyclic (D3-D7) and 11 linear (L4-L14) siloxanes were determined in 310 indoor dust samples collected from 12 countries. Dust samples collected from Greece contained the highest concentrations of total cyclic siloxanes (TCSi), ranging from 118 to 25,100ng/g (median: 1380), and total linear siloxanes (TLSi), ranging from 129 to 4990ng/g (median: 772). The median total siloxane (TSi) concentrations in dust samples from 12 countries were in the following decreasing order: Greece (2970ng/g), Kuwait (2400), South Korea (1810), Japan (1500), the USA (1220), China (1070), Romania (538), Colombia (230), Vietnam (206), Saudi Arabia (132), India (116), and Pakistan (68.3). TLSi concentrations as high as 42,800ng/g (Kuwait) and TCSi concentrations as high as 25,000ng/g (Greece) were found in indoor dust samples. Among the 16 siloxanes determined, decamethylcyclopentasiloxane (D5) was found at the highest concentration in dust samples from all countries, except for Japan and South Korea, with a predominance of L11; Kuwait, with L10; and Pakistan and Romania, with L12. The composition profiles of 16 siloxanes in dust samples varied by country. TCSi accounted for a major proportion of TSi concentrations in dust collected from Colombia (90%), India (80%) and Saudi Arabia (70%), whereas TLSi predominated in samples collected from Japan (89%), Kuwait (85%), and South Korea (78%). Based on the measured median TSi concentrations in indoor dust, we estimated human exposure doses through indoor dust ingestion for various age groups. The exposure doses ranged from 0.27 to 11.9ng/kg-bw/d for toddlers and 0.06 to 2.48ng/kg-bw/d for adults.


Asunto(s)
Contaminación del Aire Interior/análisis , Polvo/análisis , Exposición a Riesgos Ambientales/análisis , Siloxanos/análisis , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Adulto Joven
17.
Environ Int ; 75: 166-71, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25461426

RESUMEN

Perchlorate is a widespread environmental contaminant and potent thyroid hormone disrupting compound. Despite this, very little is known with regard to the occurrence of this compound in indoor dust and the exposure of humans to perchlorate through dust ingestion. In this study, 366 indoor dust samples were collected from 12 countries, the USA, Colombia, Greece, Romania, Japan, Korea, Pakistan, Kuwait, Saudi Arabia, India, Vietnam, and China, during 2010-2014. Dust samples were extracted by 1% (v/v) methylamine in water. Analyte separation was achieved by an ion exchange (AS-21) column and analysis was performed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The overall concentrations of perchlorate in dust were in the range of 0.02-104µg/g (geometric mean: 0.41µg/g). The indoor dust samples from China contained the highest concentrations (geometric mean: 5.38µg/g). No remarkable differences in perchlorate concentrations in dust were found among various microenvironments (i.e., car, home, office, and laboratory). The estimated median daily intake (EDI) of perchlorate for toddlers through dust ingestion in the USA, Colombia, Greece, Romania, Japan, Korea, Pakistan, Kuwait, Saudi Arabia, India, Vietnam, and China was 1.89, 0.37, 1.71, 0.74, 4.90, 7.20, 0.60, 0.80, 1.55, 0.70, 2.15, and 21.3ng/kgbodyweight (bw)/day, respectively. Although high concentrations of perchlorate were measured in some dust samples, the contribution of dust to total perchlorate intake was <5% of the total perchlorate intake in humans. This is the first multinational survey on the occurrence of perchlorate in indoor dust.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Polvo/análisis , Percloratos/análisis , Adolescente , Adulto , Niño , Preescolar , China , Cromatografía Líquida de Alta Presión , Colombia , Ingestión de Alimentos , Exposición a Riesgos Ambientales/análisis , Grecia , Humanos , India , Lactante , Japón , Kuwait , Pakistán , República de Corea , Rumanía , Arabia Saudita , Espectrometría de Masas en Tándem , Estados Unidos , Vietnam , Adulto Joven
18.
Environ Pollut ; 159(2): 646-53, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21035239

RESUMEN

The first survey of persistent organic pollutant (POP) concentrations in air across several Indian agricultural regions was conducted in 2006-2007. Passive samplers comprising polyurethane foam (PUF) disks were deployed on a quarterly basis at seven stations in agricultural regions, one urban site and one background site. The project was conducted as a sub-project of the Global Atmospheric Passive Sampling (GAPS) Network. In addition to revealing new information on air concentrations of several organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), the study has demonstrated the feasibility of conducting regional-scale monitoring for POPs in India using PUF disk samplers. The following analytes were detected with relatively high concentrations in air (mean for 2006 and 2007, pg/m(3)): α- and γ-hexachlorocyclohexane (HCH) (292 and 812, respectively); endosulfan I and II (2770 and 902, respectively); p,p'-DDE and p,p'-DDT (247 and 931, respectively); and for the sum of 48 PCBs, 12,100 (including a site with extremely high air concentrations in 2007) and 972 (when excluding data for this site).


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Plaguicidas/análisis , Adsorción , Agricultura , Contaminación del Aire , Monitoreo del Ambiente/instrumentación , Hidrocarburos Clorados/análisis , India , Bifenilos Policlorados/análisis , Poliuretanos/química , Estaciones del Año
19.
Chemosphere ; 76(1): 22-6, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19328520

RESUMEN

Perchlorate (ClO(4)(-)), which is used as an oxidizer in jet and rocket fuels, pyrotechnic devices and explosives, is a widespread contaminant in surface waters and groundwater of many countries. Perchlorate is known to affect thyroid function. Despite the compound's widespread occurrence and potential health effects, perchlorate levels in drinking water in India are not known. In this study, water samples collected from 13 locations in six states (n=66), and saliva samples collected from four locations in three states (n=74) in India, were analyzed for perchlorate using high performance liquid chromatography interfaced with tandem mass spectrometry (HPLC-MS/MS). Perchlorate was detected in most (76%) of the water samples analyzed at concentrations above the quantitation limit of 0.02 microg L(-1); concentrations ranged from <0.02 to 6.9 microg L(-1) (mean: 0.42+/-1.1 microg L(-1); median: 0.07 microg L(-1)). Mean concentrations of perchlorate in drinking water, groundwater, bottled water, surface water and rain water were 0.1, 1.0, <0.02, 0.05 and <0.02 microg L(-1), respectively. From a total of 66 water samples analyzed, only three samples contained perchlorate levels above 1 microg L(-1); all three were groundwater samples. Perchlorate was found in the saliva samples analyzed at concentrations above 0.2 microg L(-1) and up to 4.7 microg L(-1) (mean: 1.3+/-1.3 microg L(-1); median: 0.91 microug L(-1)). No remarkable differences in perchlorate concentrations were found among the sampling locations of water or saliva or in subgroups stratified by gender or age. Perchlorate concentrations in water samples from India are one to two orders of magnitude lower than the concentrations reported for the United States.


Asunto(s)
Agua Dulce/análisis , Percloratos/análisis , Saliva/química , Contaminantes Químicos del Agua/análisis , Adulto , Anciano , Cromatografía Líquida de Alta Presión , Femenino , Humanos , India , Masculino , Persona de Mediana Edad , Espectrometría de Masa por Ionización de Electrospray , Adulto Joven
20.
Chemosphere ; 76(1): 55-62, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19328521

RESUMEN

Despite the reports of the occurrence of perfluorochemicals (PFCs) in industrialized nations, information on PFCs in less industrialized countries is meager. In the present study, concentrations and profiles of PFCs were investigated in surface waters (rivers, lakes, coastal seas and untreated sewage; n=42) including the Ganges River water, and biota such as shrimp (n=2), fish (n=28), and Ganges River dolphin (Platanista gangetica; n=15). PFOS was the dominant PFC found in most of the samples analyzed including water samples except untreated sewage (water: <0.04-3.91 ng L(-1); biota: 0.248-27.9 ng g(-1) ww). Long-chain (C11-C18) perfluorocarboxylates (PFCAs) were not detected in the water samples (<0.2 ng L(-1)), although PFDA (0.061-0.923 ng g(-1) ww) and PFUnDA (0.072-0.998 ng g(-1) ww) were found in biological samples The arithmetic mean PFOS concentration found in the liver of Ganges River dolphin was 27.9 ng g(-1) ww. Bioconcentration and biomagnifications factors of PFCs were estimated in the Ganges River basin food web. The highest concentration of PFOA, 23.1 ng L(-1), was found in untreated sewage samples. Overall, concentrations of PFCs of water and biological samples from India are lower than the concentrations reported for other countries so far. PFC profiles in Indian waters are dominated by PFOS, followed by PFOA, which is different from the pattern reported for other countries such as Korea, Japan and USA, where PFOA was the predominant compound in waters. The flux estimates for PFOS, PFOA and PFNA from the Ganges River in India to the Bay of Bengal were in the range of several hundreds of kilograms per year.


Asunto(s)
Agua Dulce/análisis , Hidrocarburos Fluorados/análisis , Contaminantes Químicos del Agua/análisis , Animales , Biodiversidad , Delfines , Monitoreo del Ambiente , Agua Dulce/química , Hidrocarburos Fluorados/química , India , Ríos , Contaminantes Químicos del Agua/química
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