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1.
Chem Res Toxicol ; 28(2): 182-90, 2015 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-25536227

RESUMO

To estimate exposures to smokers from cigarettes, smoking topography is typically measured and programmed into a smoking machine to mimic human smoking, and the resulting smoke emissions are tested for relative levels of harmful constituents. However, using only the summary puff data--with a fixed puff frequency, volume, and duration--may underestimate or overestimate actual exposure to smoke toxins. In this laboratory study, we used a topography-driven smoking machine that faithfully reproduces a human smoking session and individual human topography data (n = 24) collected during previous clinical research to investigate if replicating the true puff profile (TP) versus the mathematically derived smoothed puff profile (SM) resulted in differences in particle size distributions and selected toxic/carcinogenic organic compounds from mainstream smoke emissions. Particle size distributions were measured using an electrical low pressure impactor, the masses of the size-fractionated fine and ultrafine particles were determined gravimetrically, and the collected particulate was analyzed for selected particle-bound, semivolatile compounds. Volatile compounds were measured in real time using a proton transfer reaction-mass spectrometer. By and large, TP levels for the fine and ultrafine particulate masses as well as particle-bound organic compounds were slightly lower than the SM concentrations. The volatile compounds, by contrast, showed no clear trend. Differences in emissions due to the use of the TP and SM profiles are generally not large enough to warrant abandoning the procedures used to generate the simpler smoothed profile in favor of the true profile.


Assuntos
Carcinógenos/análise , Carcinógenos/metabolismo , Nicotiana , Fumaça/análise , Fumar/metabolismo , Exposição Ambiental/análise , Humanos , Tamanho da Partícula , Poluição por Fumaça de Tabaco/análise , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo
2.
Int J Environ Health Res ; 25(6): 628-39, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25614176

RESUMO

Limited data exist on exposures of young children to polycyclic aromatic hydrocarbons (PAHs) in the United States (US). The urinary metabolite of pyrene, 1-hydroxypyrene (1-OHPyr), is widely used as a biomarker of total PAH exposure. Our objectives were to quantify urinary 1-OHPyr levels in 126 preschool children over a 48-h period and to examine associations between selected sociodemographic/lifestyle factors and urinary 1-OHPyr levels. Monitoring was performed at 126 homes and 16 daycares in Ohio in 2001, and questionnaires and urine samples were collected. The median urinary 1-OHPyr level was 0.33 ng/mL. In a multiple regression model, sampling season (p = 0.0001) and natural log (ln)-transformed creatinine concentration (p = 0.0006) were highly significant predictors of ln-transformed 1-OH-Pyr concentration; cooking appliance type (p = 0.096) was a marginally significant predictor of ln(1-OHPyr). These children had higher median urinary 1-OHPyr levels compared to other US children (≤ 0.15 ng/mL) in previously published studies, which suggests possible geographical differences in PAH exposure.


Assuntos
Exposição Ambiental , Poluentes Ambientais/urina , Pirenos/urina , Biomarcadores/urina , Pré-Escolar , Estudos de Coortes , Monitoramento Ambiental , Feminino , Humanos , Estilo de Vida , Masculino , Análise Multivariada , Ohio , Fatores Socioeconômicos
3.
Inhal Toxicol ; 24(5): 255-69, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22486344

RESUMO

INTRODUCTION: Research on the deposition of mainstream smoke particulate in the respiratory tract of smokers is needed to understand how exposure may vary based on cigarette menthol content. METHODS: We conducted a nine-participant crossover study in which smokers were randomly assigned to cigarettes differing primarily in menthol content. Participants smoked the test cigarettes ad libitum for one week, provided spot urine samples, and then smoked four test cigarettes in a laboratory session; this was repeated for the other test cigarette in week two. Fine and ultrafine particulate matter in exhaled breath were characterized, and smoking behavior was monitored. Participant-specific mainstream smoke, generated using each participant's topography data, was characterized. During home smoking, participants collected their spent test cigarette butts for estimates of mouth-level exposures (MLE) to mainstream nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). RESULTS: Participant-specific mainstream smoke NNK was higher (39%) and daily MLE to NNK was also higher (52%) when participants smoked the menthol cigarette. Nicotine was not significantly different. Participants retained more ultrafine particulate (43%) and fine particulate benzo(a)pyrene (43%) when smoking the menthol cigarette. There were no significant differences in the levels of urinary biomarkers for nicotine, NNK, or pyrene. CONCLUSION: This study demonstrates the use of noninvasive real-time techniques to measure exposure differences between cigarettes differing primarily in menthol content. Differences between NNK exposure, ultrafine particle and benzo(a)pyrene deposition, and smoking behavior were observed. Additional research using these techniques with cigarettes that differ only in menthol content is required to unequivocally attribute the exposure differences to presence or absence of menthol.


Assuntos
Exposição por Inalação/análise , Mentol , Material Particulado/análise , Fumaça/análise , Fumar , Adulto , Biomarcadores/urina , Estudos Cross-Over , Feminino , Humanos , Masculino , Nicotina/análise , Nitrosaminas/análise , Nitrosaminas/urina , Tamanho da Partícula , Hidrocarbonetos Policíclicos Aromáticos/urina , Nicotiana , Adulto Jovem
4.
Environ Sci Technol ; 45(12): 5309-16, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21612268

RESUMO

Limited published information exists on young children's exposures to bisphenol A (BPA) in the United States using urinary biomonitoring. In a previous project, we quantified the aggregate exposures of 257 preschool children to BPA in environmental and personal media over 48-h periods in 2000-2001 at homes and daycares in North Carolina and Ohio. In the present study for 81 Ohio preschool children ages 23-64 months, we quantified the children's urinary total BPA (free and conjugated) concentrations over these same 48-h periods in 2001. Then, we examined the quantitative relationships between the children's intakes doses of BPA through the dietary ingestion, nondietary ingestion, and inhalation routes and their excreted amounts of urinary BPA. BPA was detected in 100% of the urine samples. The estimated median intake doses of BPA for these 81 children were 109 ng/kg/day (dietary ingestion), 0.06 ng/kg/day (nondietary ingestion), and 0.27 ng/kg/day (inhalation); their estimated median excreted amount of urinary BPA was 114 ng/kg/day. Our multivariable regression model showed that dietary intake of BPA (p = 0.04) and creatinine concentration (p = 0.004) were significant predictors of urinary BPA excretion, collectively explaining 17% of the variability in excretion. Dietary ingestion of BPA accounted for >95% of the children's excreted amounts of urinary BPA.


Assuntos
Monitoramento Ambiental/métodos , Fenóis/urina , Compostos Benzidrílicos , Creches , Pré-Escolar , Poluentes Ambientais/análise , Humanos , Lactente , Exposição por Inalação/análise , Ohio , Compostos Orgânicos/análise , Praguicidas/análise , Análise de Regressão , Fatores de Tempo
5.
J Environ Sci Health B ; 46(1): 41-50, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20972922

RESUMO

An analytical method was developed for determining organophosphate pesticides (OPP) and pyrethroid pesticides (PYR) in duplicate-diet solid food. The method consisted of pressurized liquid extraction (PLE) with dichloromethane followed by cleanup with gel permeation and solid phase extraction columns and gas chromatography/mass spectrometry (GC/MS) analysis. Quantitative recoveries (73-117 %) of the target pesticides were obtained for spiked duplicate-diet food samples. The percent standard deviation (% RSD) of replicate food samples was within ± 20 %. Another method was developed for determining a common OPP metabolite, 3, 5, 6-trichloro-2-pyridinol (TCP) in duplicate-diet food. The method consisted of a PLE with methanol followed by liquid-liquid partitioning, derivatization, and GC/MS analysis. Recoveries of TCP ranged from 83 to 101 % for spiked duplicate-diet food samples. The % RSD of replicate food samples was within ± 15 %. The results confirmed that these methods are reliable and robust, and that they can be used in routine analysis. In addition, a storage stability study for a common OPP, chlorpyrifos (CPF), in solid food samples was performed. The fortified (15)N-(13)C-labeled CPF was stable over 16 mo storage at -20° C in the dark. The developed analytical methods were successfully applied to 278 duplicate-diet food samples from preschool children, demonstrating that these methods are robust and suitable for routine analysis in future exposure monitoring studies.


Assuntos
Fracionamento Químico/métodos , Contaminação de Alimentos/análise , Compostos Organofosforados/isolamento & purificação , Resíduos de Praguicidas/isolamento & purificação , Piretrinas/isolamento & purificação , Fracionamento Químico/instrumentação , Cromatografia Gasosa-Espectrometria de Massas , Compostos Organofosforados/análise , Resíduos de Praguicidas/análise , Piretrinas/análise
6.
J Environ Sci Health B ; 45(6): 516-23, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20574872

RESUMO

A low-cost, high throughput bioanalytical screening method was developed for monitoring cis/trans-permethrin in dust and soil samples. The method consisted of a simple sample preparation procedure [sonication with dichloromethane followed by a solvent exchange into methanol:water (1:1)] with bioanalytical detection using a magnetic particle enzyme-linked immunosorbent assay (ELISA). Quantitative recoveries (83-126%) of cis/trans-permethrin were obtained for spiked soil and dust samples. The percent difference of duplicate ELISA analyses was within +/- 20% for standards and +/- 35% for samples. Similar sample preparation procedures were used for the conventional gas chromatography/mass spectrometry (GC/MS) analysis except that additional cleanup steps were required. Recoveries of cis/trans-permethrin ranged from 81 to 108% for spiked soil and dust samples by GC/MS. The ELISA-derived permethrin concentrations were highly correlated with the GC/MS-derived sum of cis/trans-permethrin concentrations with a correlation coefficient (r) of 0.986. The ELISA method provided a rapid qualitative screen for cis/trans-permethrin in soil and dust while providing a higher sample throughput with a lower cost as compared to the GC/MS method. The ELISA can be applied as a complementary, low-cost screening tool to prioritize and rank samples prior to instrumental analysis for exposure studies.


Assuntos
Poeira/análise , Ensaio de Imunoadsorção Enzimática/métodos , Inseticidas/análise , Permetrina/análise , Poluentes do Solo/análise , Adsorção , Ensaio de Imunoadsorção Enzimática/instrumentação , Imunoadsorventes/química
7.
Chemosphere ; 72(1): 95-103, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18313102

RESUMO

A 96-microwell enzyme-linked immunosorbent assay (ELISA) method was evaluated to determine PCDDs/PCDFs in sediment and soil samples from an EPA Superfund site. Samples were prepared and analyzed by both the ELISA and a gas chromatography/high resolution mass spectrometry (GC/HRMS) method. Comparable method precision, accuracy, and detection level (8 ng kg(-1)) were achieved by the ELISA method with respect to GC/HRMS. However, the extraction and cleanup method developed for the ELISA requires refinement for the soil type that yielded a waxy residue after sample processing. Four types of statistical analyses (Pearson correlation coefficient, paired t-test, nonparametric tests, and McNemar's test of association) were performed to determine whether the two methods produced statistically different results. The log-transformed ELISA-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin values and log-transformed GC/HRMS-derived TEQ values were significantly correlated (r=0.79) at the 0.05 level. The median difference in values between ELISA and GC/HRMS was not significant at the 0.05 level. Low false negative and false positive rates (<10%) were observed for the ELISA when compared to the GC/HRMS at 1,000 ng TEQ kg(-1). The findings suggest that immunochemical technology could be a complementary monitoring tool for determining concentrations at the 1,000 ng TEQ kg(-1) action level for contaminated sediment and soil. The ELISA could also be used in an analytical triage approach to screen and rank samples prior to instrumental analysis.


Assuntos
Dioxinas/análise , Ensaio de Imunoadsorção Enzimática/métodos , Sedimentos Geológicos/química , Poluentes do Solo/análise , Cromatografia Gasosa-Espectrometria de Massas
8.
J Agric Food Chem ; 54(18): 6482-92, 2006 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-16939301

RESUMO

Enzyme-linked immunosorbent assay (ELISA) and sol-gel-based immunoaffinity purification (IAP) methods for the pyrethroid bioallethrin were developed and applied for monitoring bioallethrin in spiked food, soil, and dust samples. Attempts to determine bioallethrin content in fruit and vegetable extracts revealed high variability between sample preparations and marked interferences with the assay. Sol-gel IAP followed by solid-phase sample concentration was effective in removing the interfering components and resulted in high recovery of bioallethrin from spiked crude acetonic extracts of fruits and vegetables, even in the presence of high extract concentrations (28%). Solid-phase treatment alone failed to remove the interfering components from the spiked sample. Gas chromatography-mass spectrometry analysis of the IAP samples revealed bioallethrin as a doublet unsolved peak because of the cis and trans isomer present in the standard with confirmation of its mass. Unlike fruit and vegetable extracts, soil and dust samples did not interfere with the ELISA, and the bioallethrin content in those samples could be determined with high precision without the need of any further purification.


Assuntos
Aletrinas/isolamento & purificação , Cromatografia de Afinidade/métodos , Poeira/análise , Ensaio de Imunoadsorção Enzimática , Análise de Alimentos/métodos , Solo/análise , Frutas/química , Técnicas Imunológicas , Verduras/química
9.
J Expo Anal Environ Epidemiol ; 15(4): 297-309, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15367928

RESUMO

As part of the Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study, we investigated the exposures of preschool children to chlorpyrifos and its degradation product 3,5,6-trichloro-2-pyridinol (TCP) in their everyday environments. During this study, the participants were still able to purchase and apply chlorpyrifos at their homes or day care centers. Participants were recruited randomly from 129 homes and 13 day care centers in six North Carolina counties. Monitoring was performed over a 48-h period at the children's homes and/or day care centers. Samples that were collected included duplicate plate, indoor and outdoor air, urine, indoor floor dust, play area soil, transferable residues (PUF roller), and surface wipes (hand, food preparation, and hard floor). The samples were extracted and analyzed by gas chromatography/mass spectrometry. Chlorpyrifos was detected in 100% of the indoor air and indoor floor dust samples from homes and day care centers. TCP was detected at homes and day care centers in 100% of the indoor floor dust and hard floor surface wipe, in >97% of the solid food, and in >95% of the indoor air samples. Generally, median levels of chlorpyrifos were higher than those of TCP in all media, except for solid food samples. For these samples, the median TCP concentrations were 12 and 29 times higher than the chlorpyrifos concentrations at homes and day care centers, respectively. The median urinary TCP concentration for the preschool children was 5.3 ng/ml and the maximum value was 104 ng/ml. The median potential aggregate absorbed dose (ng/kg/day) of chlorpyrifos for these preschool children was estimated to be 3 ng/kg/day. The primary route of exposure to chlorpyrifos was through dietary intake, followed by inhalation. The median potential aggregate absorbed dose of TCP for these children was estimated to be 38 ng/kg/day, and dietary intake was the primary route of exposure. The median excreted amount of urinary TCP for these children was estimated to be 117 ng/kg/day. A full regression model of the relationships among chlorpyrifos and TCP for the children in the home group explained 23% of the variability of the urinary TCP concentrations by the three routes of exposure (inhalation, ingestion, dermal absorption) to chlorpyrifos and TCP. However, a final reduced model via step-wise regression retained only chlorpyrifos through the inhalation route and explained 22% of the variability of TCP in the children's urine. The estimated potential aggregate absorbed doses of chlorpyrifos through the inhalation route were low (median value, 0.8 ng/kg/day) and could not explain most of the excreted amounts of urinary TCP. This suggested that there were other possible sources and pathways of exposure that contributed to the estimated potential aggregate absorbed doses of these children to chlorpyrifos and TCP. One possible pathway of exposure that was not accounted for fully is through the children's potential contacts with contaminated surfaces at homes and day care centers. In addition, other pesticides such as chlorpyrifos-methyl may have also contributed to the levels of TCP in the urine. Future studies should include additional surface measurements in their estimation of potential absorbed doses of preschool children to environmental pollutants. In conclusion, the results showed that the preschool children were exposed to chlorpyrifos and TCP from several sources, through several pathways and routes. .


Assuntos
Creches , Clorpirifos/análise , Habitação , Inseticidas/análise , Resíduos de Praguicidas/análise , Piridonas/análise , Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Biomarcadores/urina , Pré-Escolar , Poeira/análise , Monitoramento Ambiental , Poluentes Ambientais/análise , Pisos e Cobertura de Pisos , Análise de Alimentos , Contaminação de Alimentos , Humanos , Lactente , North Carolina , Piridonas/urina , Solo/análise
10.
J Expo Anal Environ Epidemiol ; 13(3): 187-202, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12743613

RESUMO

In the summer of 1997, we measured the aggregate exposures of nine preschool children, aged 2-5 years, to a suite of organic pesticides and other persistent organic pollutants that are commonly found in the home and school environment. The children attended either of two child day care centers in the Raleigh-Durham-Chapel Hill area of North Carolina and were in day care at least 25 h/week. Over a 48-h period, we sampled indoor and outdoor air, play area soil and floor dust, as well as duplicate diets, hand surface wipes, and urine for each child at day care and at home. Our target analytes were several polycyclic aromatic hydrocarbons (PAH), organochlorine pesticides, and polychlorinated biphenyls (PCB); two organophosphate pesticides (chlorpyrifos and diazinon), the lawn herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), three phenols (pentachlorophenol (PCP), nonyl phenols, and bisphenol-A), 3,5,6-trichloro-2-pyridinol (TCP), and two phthalate esters (benzylbutyl and dibutyl phthalate). In urine, our target analytes were hydroxy-PAH, TCP, 2,4-D, and PCP. To allow estimation of each child's aggregate exposures over the 48-h sampling period, we also used time-activity diaries, which were filled out by each child's teacher at day care and the parent or other primary caregiver at home. In addition, we collected detailed household information that related to potential sources of exposure, such as pesticide use or smoking habits, through questionnaires and field observation. We found that the indoor exposures were greater than those outdoors, that exposures at day care and at home were of similar magnitudes, and that diet contributed greatly to the exposures. The children's potential aggregate doses, calculated from our data, were generally well below established reference doses (RfDs) for those compounds for which RfDs are available.


Assuntos
Creches , Exposição Ambiental/análise , Poluentes Ambientais/análise , Habitação , Biomarcadores/urina , Pré-Escolar , Monitoramento Ambiental/métodos , Contaminação de Alimentos/análise , Mãos , Humanos , Hidrocarbonetos Aromáticos , North Carolina , Praguicidas/análise , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise
11.
J Expo Anal Environ Epidemiol ; 14(3): 260-74, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15141155

RESUMO

Young children, because of their immaturity and their rapid development compared to adults, are considered to be more susceptible to the health effects of environmental pollutants. They are also more likely to be exposed to these pollutants, because of their continual exploration of their environments with all their senses. Although there has been increased emphasis in recent years on exposure research aimed at this specific susceptible population, there are still large gaps in the available data, especially in the area of chronic, low-level exposures of children in their home and school environments. A research program on preschool children's exposures was established in 1996 at the USEPA National Exposure Research Laboratory. The emphasis of this program is on children's aggregate exposures to common contaminants in their everyday environments, from multiple media, through all routes of exposure. The current research project, "Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants," (CTEPP), is a pilot-scale study of the exposures of 257 children, ages 1(1/2)-5 years, and their primary adult caregivers to contaminants in their everyday surroundings. The contaminants of interest include several pesticides, phenols, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and phthalate esters. Field recruitment and data collection began in February 2000 in North Carolina and were completed in November 2001 in Ohio. This paper describes the design strategy, survey sampling, recruiting, and field methods for the CTEPP study.


Assuntos
Proteção da Criança , Exposição Ambiental , Poluentes Ambientais/análise , Praguicidas/análise , Creches , Pré-Escolar , Coleta de Dados , Poluentes Ambientais/efeitos adversos , Estudos Epidemiológicos , Feminino , Humanos , Lactente , Masculino , Compostos Orgânicos , Seleção de Pacientes , Praguicidas/efeitos adversos , Projetos de Pesquisa , Tamanho da Amostra
12.
Int J Environ Res Public Health ; 11(4): 3743-64, 2014 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-24705361

RESUMO

Few data exist on the concurrent exposures of young children to past-use and current-use pesticides in their everyday environments. In this further analysis of study data, we quantified the potential exposures and intake doses of 129 preschool children, ages 20 to 66 months, to 16 pesticides (eight organochlorines, two organophosphates, three pyrethroids, and three acid herbicides). Environmental samples (soil, dust, outdoor air, and indoor air) and personal samples (hand wipes, solid food, and liquid food) were collected at 129 homes and 13 daycare centers in six counties in North Carolina between 2000 and 2001. α-Chlordane, γ-chlordane, heptachlor, chlorpyrifos, diazinon, cis-permethrin, trans-permethrin, and 2,4-dichlorophenoxyacetic acid (2,4-D) were detected ≥50% in two or more media in both settings. Of these pesticides, the children's estimated median potential intake doses through dietary ingestion, nondietary ingestion, and inhalation routes were the highest for 2,4-D and cis/trans-permethrin (both 4.84 ng/kg/day), cis/trans-permethrin (2.39 ng/kg/day), and heptachlor (1.71 ng/kg/day), respectively. The children's estimated median potential aggregate intake doses by all three routes were quantifiable for chlorpyrifos (4.6 ng/kg/day), cis/trans-permethrin (12.5 ng/kg/day), and 2,4-D (4.9 ng/kg/day). In conclusion, these children were likely exposed daily to several pesticides from several sources and routes at their homes and daycares.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Contaminação de Alimentos/análise , Herbicidas/análise , Inseticidas/análise , Poluentes do Solo/análise , Criança , Creches , Pré-Escolar , Poeira/análise , Monitoramento Ambiental , Feminino , Habitação , Humanos , Hidrocarbonetos Clorados/análise , Lactente , Exposição por Inalação/análise , Masculino , North Carolina , Organofosfatos/análise , Piretrinas/análise
13.
Chemosphere ; 90(1): 1-6, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22906485

RESUMO

An immunoaffinity chromatography (IAC) column was developed as a simple cleanup procedure for preparing environmental samples for analysis of polychlorinated biphenyls (PCBs). Soil and sediment samples were prepared using pressurized liquid extraction (PLE), followed by the IAC cleanup, with detection by an enzyme-linked immunosorbent assay (ELISA). Quantitative recoveries (84-130%) of PCB-126 were obtained in fortified sediment and soil samples using the PLE/IAC/ELISA method. These results demonstrated that the IAC procedure effectively removed interferences from the soil and sediment matrices. The IAC column could be reused more than 20 times with no change in performance with 99.9% methanol/0.1% Triton X-100 as the elution solvent. Results of 17 soil and sediment samples prepared by PLE/IAC/ELISA correlated well with those obtained from a conventional multi-step cleanup with gas chromatography/mass spectrometry detection.


Assuntos
Cromatografia de Afinidade/métodos , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Bifenilos Policlorados/análise , Poluentes do Solo/análise , Solo/química , Ensaio de Imunoadsorção Enzimática , Cromatografia Gasosa-Espectrometria de Massas , Técnicas Imunológicas , Octoxinol , Bifenilos Policlorados/química , Poluentes do Solo/química
14.
Sci Total Environ ; 463-464: 326-33, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23827357

RESUMO

A selective pressurized liquid extraction (SPLE) method was developed for a streamlined sample preparation/cleanup to determine Aroclors and coplanar polychlorinated biphenyls (PCBs) in soil and sediment. The SPLE was coupled with an enzyme-linked immunosorbent assay (ELISA) for an effective analytical approach for environmental monitoring. Sediment or soil samples were extracted with alumina, 10% AgNO3 in silica, and sulfuric acid impregnated silica with dichloromethane at 100°C and 2000 psi. The SPLE offered simultaneous extraction and cleanup of the PCBs and Aroclors, eliminating the need for a post-extraction cleanup prior to ELISA. Two different ELISA methods: (1) an Aroclor ELISA and (2) a coplanar PCB ELISA were evaluated. The Aroclor ELISA utilized a polyclonal antibody (Ab) with Aroclor 1254 as the calibrant and the coplanar PCB ELISA kit used a rabbit coplanar PCB Ab with PCB-126 as the calibrant. Recoveries of Aroclor 1254 in two reference soil samples were 92±2% and 106±5% by off-line coupling of SPLE with ELISA. The average recovery of Aroclor 1254 in spiked soil and sediment samples was 92±17%. Quantitative recoveries of coplanar PCBs (107-117%) in spiked samples were obtained with the combined SPLE-ELISA. The estimated method detection limit was 10 ng g(-1) for Aroclor 1254 and 125 pg g(-1) for PCB-126. Estimated sample throughput for the SPLE-ELISA was about twice that of the stepwise extraction/cleanup needed for gas chromatography (GC) or GC/mass spectrometry (MS) detection. ELISA-derived uncorrected and corrected Aroclor 1254 levels correlated well (r=0.9973 and 0.9996) with the total Aroclor concentrations as measured by GC for samples from five different contaminated sites. ELISA-derived PCB-126 concentrations were higher than the sums of the 12 coplanar PCBs generated by GC/MS with a positive correlation (r=0.9441). Results indicate that the SPLE-ELISA approach can be used for quantitative or qualitative analysis of PCBs in soil and sediments. To our knowledge, this is the first report of an SPLE-ELISA approach not requiring a post-extraction cleanup step for detecting Aroclors and coplanar PCBs in soil and sediment.

15.
Anal Chim Acta ; 745: 38-44, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22938604

RESUMO

An efficient and reliable analytical method was developed for the sensitive and selective quantification of pyrethroid pesticides (PYRs) in house dust samples. The method is based on selective pressurized liquid extraction (SPLE) of the dust-bound PYRs into dichloromethane (DCM) with analysis by gas chromatography/mass spectrometry. Various adsorbents and combinations of extraction solvents and temperatures were evaluated to achieve a high-throughput sample preparation that eliminates the post-extraction cleanup step. The final method used sulfuric acid-impregnated silica (acid silica) and neutral silica together in the extraction cell with the dust sample to provide both extraction and cleanup simultaneously. The optimal ratio of dust/acid silica/silica was 1:0.8:8. The extraction was performed at 2000 psi, at 100°C with DCM for 5 min in three cycles. Method precision and accuracy were evaluated by the analysis of triplicate aliquots of the dust samples and the samples fortified with the target PYRs. The accuracy measured as the recoveries of the PYRs in the fortified samples ranged from 85% to 120%. The precision measured as the relative standard deviation of replicate samples was within ±25%. The SPLE method was applied to 20 house dust samples collected from households that participated in two field studies regarding exposures to pesticides and other pollutants. Similar concentrations of target PYRs were obtained for the SPLE and a stepwise extraction/cleanup procedure. The SPLE procedure reduces organic solvent consumption and increases the sample throughput when compared with a traditional stepwise extraction and cleanup procedure. This study demonstrates that the SPLE procedure can be applied to complex dust matrices for analysis of PYRs for large scale exposure or environmental monitoring studies.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Métodos Analíticos de Preparação de Amostras/métodos , Poeira/análise , Extração Líquido-Líquido/métodos , Piretrinas/isolamento & purificação , Monitoramento Ambiental , Poluentes Ambientais/análise , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Inseticidas/isolamento & purificação , Cloreto de Metileno/química , Reprodutibilidade dos Testes
16.
J Agric Food Chem ; 60(17): 4235-42, 2012 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-22420505

RESUMO

Development of a multianalyte enzyme-linked immunosorbent assay (ELISA) for detection of permethrin and aroclors 1248 or 1254 and implementation of the assay for analysis of soil/sediment samples are described. The feasibility of using the multianalyte ELISA to monitor aroclors 1254 and permethrin simultaneously was tested with permethrin and aroclor standards and with aroclor- and permethrin-containing soil/sediment and house dust samples. Comparison of the I50 and I20 values of the multianalyte with those of a single-analyte assay revealed similar results, and multianalyte ELISA determination of analyte amounts in soil/sediment dust samples yielded similar results to those of a single-analyte assay. A single-analyte assay of permethrin content in permethrin-containing dust samples showed that the ELISA can determine the analyte accurately in samples with dust matrix contents ranging from 6.25 to 100 mg as indicated by the good correlation between the results of the immunoassay and those of the gas chromatography analysis.


Assuntos
Arocloros/análise , Poeira/análise , Ensaio de Imunoadsorção Enzimática/métodos , Sedimentos Geológicos/química , Permetrina/análise , Solo/análise , Poluentes Ambientais/análise , Inseticidas/análise
17.
Talanta ; 83(5): 1317-23, 2011 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-21238715

RESUMO

An enzyme-linked immunosorbent assay (ELISA) method was employed for determination of the pyrethroid biomarker, 3-phenoxybenzoic acid (3-PBA) in human urine samples. The optimized coating antigen concentration was 0.5 ng/mL with a dilution of 1:4000 for the 3-PBA antibody and 1:6000 for the enzyme conjugate. Urine samples were hydrolyzed with concentrated hydrochloric acid; extracted with dichloromethane and solvent-exchanged into a methanol/buffer solution, prior to analysis in a 96-microwell plate immunoassay. Quantitative recoveries of 3-PBA were obtained for fortified urine samples by ELISA (92±18%) as well as by gas chromatography/mass spectrometry (GC/MS) (90±13%). The overall method precision of these samples was within ±20% for both the ELISA and GC/MS methods. Analytical results from over one hundred urine samples showed that the ELISA and GC/MS data were highly correlated, with a correlation coefficient of 0.95. At the 10 ng/mL comparative concentration level, the false positive rate was 0% and the false negative rate was 0.8% for ELISA when using GC/MS as the reference method. The ELISA method has a suitable low detection limit for 3-PBA to assess pyrethroid exposures in non-occupational settings.


Assuntos
Benzoatos/urina , Biomarcadores/urina , Ensaio de Imunoadsorção Enzimática/métodos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Inseticidas/química , Inseticidas/urina , Limite de Detecção , Piretrinas/química , Piretrinas/urina
18.
J Expo Sci Environ Epidemiol ; 21(3): 280-90, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20502492

RESUMO

A few studies have reported concurrent levels of chlorpyrifos (CPF) and diazinon (DZN) and their environmentally occurring metabolites, 3,5,6-trichloro-2-pyridinol (TCP) and 2-isopropyl-6-methyl-4-pyrimidinol (IMP), in food and in environmental media. This information raises questions regarding the reliability of using these same metabolites, TCP and IMP, as urinary biomarkers to quantitatively assess the everyday exposures of children to CPF and DZN, respectively. In this study, we quantified the distributions of CPF, DZN, TCP, and IMP in several environmental and personal media at the homes and day-care centers of 127 Ohio preschool children and identified the important sources and routes of their exposures. The children were exposed to concurrent levels of these four chemicals from several sources and routes at these locations. DZN and IMP were both detected above 50% in the air and dust samples. CPF and TCP were both detected in greater than 50% of the air, dust (solid), food, and hand wipe samples. TCP was detected in 100% of the urine samples. Results from our regression models showed that creatinine levels (<0.001), and dietary (P<0.001) and inhalation (P<0.10) doses of TCP were each significant predictors of urinary TCP, collectively explaining 27% of the urinary TCP variability. This information suggests that measurement of urinary TCP did not reliably allow quantitative estimation of the children's everyday environmental exposures to CPF.


Assuntos
Biomarcadores/urina , Clorpirifos/análise , Diazinon/análise , Exposição Ambiental , Poluentes Ambientais/análise , Inseticidas/análise , Criança , Humanos , Ohio , Controle de Qualidade , Padrões de Referência , Reprodutibilidade dos Testes
19.
J Expo Sci Environ Epidemiol ; 20(6): 546-58, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19724304

RESUMO

The impact of the US EPA-required phase-outs starting in 2000-2001 of residential uses of the organophosphate (OP) pesticides chlorpyrifos (CPF) and diazinon (DZN) on preschool children's pesticide exposures was investigated over 2003-2005, in the Raleigh-Durham-Chapel Hill area of North Carolina. Data were collected from 50 homes, each with a child initially of age 3 years (OCh) and a younger child (YCh). Environmental samples (indoor and outdoor air, dust, soil) and child-specific samples (hand surface residue, urine, diet) were collected annually over 24-h periods at each home. Child time-activity diaries and household pesticide use information were also collected. Analytes included CPF and DZN; pentachlorophenol (PCP); 2,4-dichlorophenoxyacetic acid (2,4-D); the CPF metabolite 3,5,6-trichloro-2-pyridinol (TCP); and the DZN metabolite 2-isopropyl-6-methyl-4-pyrimidinol (IMP). Exposures (ng/day) through the inhalation, dietary ingestion, and indirect ingestion were calculated. Aggregate potential doses in ng/kg body weight per day (ng/kg/day) were obtained by summing the potential doses through the three routes of exposure. Geometric mean aggregate potential doses decreased from 2003 to 2005 for both OCh and YCh, with the exception of 2,4-D. Child-specific longitudinal modeling indicated significant declines across time of the potential doses of CPF, DZN, and PCP for both children; declines of IMP for both children, significant only for OCh; a decline of TCP for OCh but an increase of TCP for YCh; and no significant change of 2,4-D for either child. Age-adjusted modeling indicated significant effects of the child's age for all except CPF, and of time for all except PCP and 2,4-D. Within-home variability was small compared with that between homes; variability was smallest for 2,4-D, both within and between homes. The aggregate potential doses of CPF and DZN were well below published reference dose values. These findings show the success of the US EPA restrictions in reducing young children's pesticide exposures.


Assuntos
Exposição Ambiental/análise , Herbicidas/análise , Inseticidas/análise , Ácido 2,4-Diclorofenoxiacético/análise , Pré-Escolar , Clorpirifos/análise , Diazinon/análise , Ingestão de Alimentos , Monitoramento Ambiental/métodos , Feminino , Contaminação de Alimentos/análise , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Lactente , Exposição por Inalação/análise , Modelos Lineares , Estudos Longitudinais , Masculino , North Carolina , Pentaclorofenol/análise , Piridonas/análise , Absorção Cutânea
20.
Anal Chim Acta ; 675(2): 138-47, 2010 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-20800725

RESUMO

Two polychlorinated biphenyls (PCB) enzyme linked immunosorbent assays (ELISAs) were developed using goat PCB purified immunoglobulin (IgG) antibodies (Abs). The IgGs exhibited the highest affinity toward PCB-77 (24 ng mL(-1)) with sensitivities in the range of 6-11 ng mL(-1). The Abs cross-reacted with PCB-126 and the heptachlorodibenzofuran 1,2,3,4,6,7,8-HpCDF but not with PCB-169, PCB-118, Aroclor 1232, 1248, 1260 or the hexachlorodibenzofuran 2,3,4,6,7,8-HxCDF. The IgGs were also used to develop a sol-gel-based immunoaffinity purification (IAP) method for cleanup of PCB-126. Recovery efficiencies depended on the sol-gel formats; a 1:12 format resulted in the highest binding capacity. Net binding capacity ranged from 112 to 257 ng, and 90% of the analyte could be eluted with only 2 mL of ethanol. The method was also very efficient in purifying PCB-126 from spiked soil and sediment samples from contaminated sites; and eliminating matrix interferences to a degree that enabled analysis of the purified samples by ELISA. The approaches developed in the course of the study form a basis for the development of additional IAP methods for other PCBs, and their implementation in high-throughput screening programs for PCB in food, soil, and other environmental and biological samples.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Imunoglobulina G/imunologia , Bifenilos Policlorados/análise , Bifenilos Policlorados/imunologia , Solo/análise , Animais , Cabras , Transição de Fase , Bifenilos Policlorados/isolamento & purificação , Sensibilidade e Especificidade
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