Environmental Health Laboratory Branch

Parkway, CA, United States

Environmental Health Laboratory Branch

Parkway, CA, United States
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Wagner J.,Environmental Health Laboratory Branch | Naik-Patel K.,Centers for Disease Control and Prevention | Naik-Patel K.,Environmental Health Investigations Branch | Wall S.,Environmental Health Laboratory Branch | Harnly M.,Environmental Health Investigations Branch
Atmospheric Environment | Year: 2012

Computer-controlled scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to obtain ambient PM mass concentrations, elemental size distributions, morphologies, and particle types during four Bermuda grass burn events in Imperial Valley, California. Passive PM samplers were deployed to three to six locations surrounding each burn for durations of 24-120 h. Average PM 2.5 and PM 10 levels were modestly but significantly higher at locations less than 3.2 km (two miles) from the nearest burn (n = 37). During one monitored burn, higher winds caused an intense ground-level plume to envelop two samplers mounted on telephone poles very close to the field. For this event, 24-h PM 2.5 exposures downwind were up to 17 times higher than that measured upwind. Particles were classified into five distinct chemical types consistent with local area sources. Burn-related particle types, primarily submicron carbonaceous particles, contributed 95% of the PM 2.5 in the location directly impacted by the ground-level plume, compared to only 12% in the upwind location. Downwind PM 10-2.5 particles were enriched in potassium, phosphorus, chlorine, calcium, silicon, and sulfur, consistent with analyses of bulk and partially-burned Bermuda grass. The accuracy and precision of passive sampler PM measurements were all within 4 μg m -3, though low median values caused high percent differences for PM 2.5. The use of electron microscopy and passive sampling in this study enabled detailed PM characterizations, spatial comparisons, and rapid deployment in often dynamic sampling scenarios. © 2012 Elsevier Ltd.

She J.,Environmental Health Laboratory Branch | She Y.,Food and Drug Laboratory Branch | Song W.,Food and Drug Laboratory Branch
Science China Chemistry | Year: 2010

In an effort to investigate the status of human exposure to PBDEs in China, available monitoring data in human specimens (including breast milk, serums, and blood) was collected from the general population as well as specific groups that are occupationally exposed. PBDEs exposure profiles and concentration levels were compared with their counterparts in the United States of America. It was found that PBDE burdens in general Chinese population are one order lower and have different congener profiles from that in the US, showing higher percentages of BDE-28 or BDE-153 in human specimens from China. Workers and residents in electronic wastes recycling regions or areas of commercial PBDE manufacturing have the highest PBDE exposure levels reported worldwide, which are close or higher than the exposure levels of the general population in the US. Highly brominated congeners, such as BDE-207 and 209, are among the major PBDE congeners, and BDE-209 has the highest percentage (above 50%) for all occupational populations studied. Principal components analysis (PCA) demonstrates that the exposure of the general population in the US is closely related to penta-BDE while the human burden in China is not. The PBDE in indoor air (gas phase) in the US is highly correlated with the PBDE burden in the general population in the US, indicating a major exposure pathway. For the occupationally exposed populations in China, the congener profiles are closely related to the commercial deca-BDE products. Examination of exposure profiles for general and occupational populations in China suggests that it is essential to include more highly brominated congeners, such as BDE-207 and 209, in future human exposure studies, in order to assess the real burdens and profiles of PBDEs exposure in China. Strict pollution prevention and occupational protection procedures are in need in China to avoid the PBDE contamination problem that has occurred in the US. © Science China Press and Springer-Verlag Berlin Heidelberg 2010.

Mendell M.J.,Environmental Health Laboratory Branch | Mendell M.J.,Lawrence Berkeley National Laboratory | Mirer A.G.,University of Wisconsin - Madison | Cheung K.,Massey University | And 2 more authors.
Environmental Health Perspectives | Year: 2011

OBjectives: Many studies have shown consistent associations between evident indoor dampness or mold and respiratory or allergic health effects, but causal links remain unclear. Findings on measured microbiologic factors have received little review. We conducted an updated, comprehensive review on these topics. D ata sources: We reviewed eligible peer-reviewed epidemiologic studies or quantitative meta-analyses, up to late 2009, on dampness, mold, or other microbiologic agents and respiratory or allergic effects. D ata extraction: We evaluated evidence for causation or association between qualitative/subjective assessments of dampness or mold (considered together) and specific health outcomes. We separately considered evidence for associations between specific quantitative measurements of microbiologic factors and each health outcome. D ata synthesis: Evidence from epidemiologic studies and meta-analyses showed indoor dampness or mold to be associated consistently with increased asthma development and exacerbation, current and ever diagnosis of asthma, dyspnea, wheeze, cough, respiratory infections, bronchitis, allergic rhinitis, eczema, and upper respiratory tract symptoms. Associations were found in allergic and nonallergic individuals. Evidence strongly suggested causation of asthma exacerbation in children. Suggestive evidence was available for only a few specific measured microbiologic factors and was in part equivocal, suggesting both adverse and protective associations with health. C onclusions: Evident dampness or mold had consistent positive associations with multiple allergic and respiratory effects. Measured microbiologic agents in dust had limited suggestive associations, including both positive and negative associations for some agents. Thus, prevention and remediation of indoor dampness and mold are likely to reduce health risks, but current evidence does not support measuring specific indoor microbiologic factors to guide health-protective actions.

Fan R.,South China Normal University | Wang D.,Environmental Health Laboratory Branch | She J.,Environmental Health Laboratory Branch
Analytical Methods | Year: 2015

This study reports a method to simultaneously determine trans,trans-muconic acid (t,t-MA), 1,2-dihydroxybenzene (or catechol, abbreviated as 1,2-DB), S-phenylmercapturic acid (S-PMA) and S-benzylmercapturic acid (S-BMA) in human urine. Samples were prepared through a solid phase extraction and analyzed by ultra-high performance liquid chromatography/tandem mass spectrometer in negative electrospray ionization mode. The method was completely validated through the studies of precision, accuracy, matrix effects, detection limit, linear range, stability and real urine sample tests. Calibration curves of all the target analytes showed a favorable linearity within the wide concentration range of 0.2-4000 μg L-1. The detection limits in 10 times diluted pooled urine ranged from 0.08 to 7.8 μg L-1. The method showed satisfactory accuracies and precisions. Except for the low spiked quality control (QC) level of 1,2-DB (73.1% recovery), the recoveries were in the range of 100% ± 15% with a variation coefficient of less than 15%. The target analytes were stable in stock solutions and spiked urine samples under storage and test conditions. Thirty three anonymous real urine samples from non-occupational donors were analyzed for all the target analytes. The preliminary results showed that S-BMA was a sensitive and specific biomarker of toluene exposure and had a significant correlation with t,t-MA (r = 0.631, p < 0.01). Moreover, S-BMA and S-PMA together could reflect the overall exposure to BT at low levels. This journal is © The Royal Society of Chemistry.

Fan R.,South China Normal University | Fan R.,Environmental Health Laboratory Branch | Ramage R.,Environmental Health Laboratory Branch | Wang D.,Environmental Health Laboratory Branch | And 2 more authors.
Talanta | Year: 2012

The aim of this study is to develop and validate an analytical method for the quantitation of ten urinary monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) through high pressure liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). After enzymatic deconjugation, urine samples were extracted by liquid-liquid extraction (LLE) and OH-PAHs were analyzed by HPLC/MS/MS operated in negative electrospray ionization (ESI) and multiple reaction monitoring (MRM) mode. LLE was conducted with the solvent mixture of pentane and toluene, which reduced the matrix interferences and enhanced the method sensitivity significantly. Deuterated and 13C-labeled analogs are used as internal standards. Calibration curves of all target analytes shows favorable linearity within the concentration range of 5.9-15,000.0 ng/L for different OH-PAHs with the regression coefficients above 0.993. The limits of detection (LODs) in pooled urine ranged from 1.72 to 17.47 ng/L, which were much lower than those obtained by a gas chromatography/high resolution mass spectrometry (GC/HRMS) method. The method shows satisfactory accuracy and precision when analyzing three different levels of OH-PAHs spiked in pooled urine. Except for 1-hydroxynaphthalene, recoveries of other OH-PAHs were in the range of 100 ± 20% with a variation coefficient of less than 13%. The measurement of OH-PAHs from a QC sample of the Centers for Disease Control and Prevention (CDC) generated results close to the values measured by CDC. This method has been successfully employed in the California Biomonitoring Program. © 2012 Elsevier B.V. All rights reserved.

Ghosal S.,Environmental Health Laboratory Branch | Fang H.,Environmental Health Laboratory Branch
Talanta | Year: 2014

Flame retardants (FRs), a class of commonly used chemical additives in consumer products such as polyurethane foams, are well known for their persistence in the environment, bioaccumulation and potential toxicity [1]. In order to address the potential health concerns and environmental impacts associated with the wide-spread use these chemicals, it is essential to identify them efficiently in the environment and consumer products. Raman spectroscopy (RS) offers an attractive option for the non-invasive, in-situ identification of flame retardants in a variety of sample formats [2-4]. RS based chemical identification relies on the availability of spectral libraries for identification through spectral matching with reference chemicals. Here we present the application of Raman spectroscopy for identifying FR additives in select consumer products using an acquired spectral library of commonly used FRs. The RS based method described here enables simultaneous identification of multiple components within a sample, which can offer important insights into the sources of FR contamination, in addition to identification of the FR component itself. The availability of Raman spectral library of commercially used FRs, such as the one presented here, will facilitate the identification of these chemicals in consumer products.

Gavin Q.W.,Environmental Health Laboratory Branch | Ramage R.T.,Environmental Health Laboratory Branch | Waldman J.M.,Environmental Health Laboratory Branch | She J.,Environmental Health Laboratory Branch
International Journal of Environmental Analytical Chemistry | Year: 2014

We present a sensitive method for simultaneous determination of bisphenol A (BPA), benzophenone-3 (BP-3), 4-tert-octylphenol (t-OP), ortho-phenylphenol (OPP), four parabens (methyl, ethyl, propyl, butyl parabens) and five chlorophenols (2,4-dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), 2,4,5-trichlorophenol (2,4,5-triclorophenol), 2,4,6-trichlorophenol (2,4,6-TCP), and triclosan (TCS)), in human urine by high-pressure liquid chromatography (HPLC) mass spectrometry (MS). Samples were processed using enzymatic deconjugation of glucuronides followed by solid phase extraction (SPE) on a C18 cartridge and the eluate was concentrated. Analytes were separated by reversed-phase HPLC and then detected by atmospheric pressure chemical ionisation (APCI) MS and quantified by isotope dilution method. We describe details for optimisation of each step of the procedure. The sample treatment steps are straightforward and not labour-intensive and, therefore, permit a high sample throughput with excellent prospects for automation. This method shows low inter-day variation, and detection limits for most of the compounds are below 1 ng/mL in 1 mL of urine. The method accuracy was also verified by the analysis of proficiency testing urine samples. © 2013 © Taylor & Francis.

We present correlated application of two micro-analytical techniques: scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS) for the non-invasive characterization and molecular identification of flame retardants (FRs) in environmental dusts and consumer products. The SEM/EDS-RMS technique offers correlated, morphological, molecular, spatial distribution and semi-quantitative elemental concentration information at the individual particle level with micrometer spatial resolution and minimal sample preparation. The presented methodology uses SEM/EDS analyses for rapid detection of particles containing FR specific elements as potential indicators of FR presence in a sample followed by correlated RMS analyses of the same particles for characterization of the FR sub-regions and surrounding matrices. The spatially resolved characterization enabled by this approach provides insights into the distributional heterogeneity as well as potential transfer and exposure mechanisms for FRs in the environment that is typically not available through traditional FR analysis. We have used this methodology to reveal a heterogeneous distribution of highly concentrated deca-BDE particles in environmental dust, sometimes in association with identifiable consumer materials. The observed coexistence of deca-BDE with consumer material in dust is strongly indicative of its release into the environment via weathering/abrasion of consumer products. Ingestion of such enriched FR particles in dust represents a potential for instantaneous exposure to high FR concentrations. Therefore, correlated SEM/RMS analysis offers a novel investigative tool for addressing an area of important environmental concern.© 2013 The Royal Society of Chemistry.

Ghosal S.,Environmental Health Laboratory Branch | MacHer J.M.,Environmental Health Laboratory Branch | Ahmed K.,University of California at Berkeley
Environmental Science and Technology | Year: 2012

We present an application of Raman microspectroscopy (RMS) for the rapid characterization and identification of individual spores from several species of microfungi. The RMS-based methodology requires minimal sample preparation and small sample volumes for analyses. Hence, it is suitable for preserving sample integrity while providing micrometer-scale spatial resolution required for the characterization of individual cells. We present the acquisition of unique Raman spectral signatures from intact fungal spores dispersed on commercially available aluminum foil substrate. The RMS-based method has been used to compile a reference library of Raman spectra from several species of microfungi typically associated with damp indoor environments. The acquired reference spectral library has subsequently been used to identify individual microfungal spores through direct comparison of the spore Raman spectra with the reference spectral signatures in the library. Moreover, the distinct peak structures of Raman spectra provide detailed insight into the overall chemical composition of spores. We anticipate potential application of this methodology in the fields of public health, forensic sciences, and environmental microbiology. © 2012 American Chemical Society.

Wagner J.,Environmental Health Laboratory Branch | Ghosal S.,Environmental Health Laboratory Branch | Whitehead T.,University of California at Berkeley | Metayer C.,University of California at Berkeley
Environment International | Year: 2013

We characterized flame retardant (FR) morphologies and spatial distributions in 7 consumer products and 7 environmental dusts to determine their implications for transfer mechanisms, human exposure, and the reproducibility of gas chromatography-mass spectrometry (GC-MS) dust measurements. We characterized individual particles using scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS). Samples were screened for the presence of 3 FR constituents (bromine, phosphorous, non-salt chlorine) and 2 metal synergists (antimony and bismuth). Subsequent analyses of select samples by RMS enabled molecular identification of the FR compounds and matrix materials. The consumer products and dust samples possessed FR elemental weight percents of up to 36% and 31%, respectively. We identified 24 FR-containing particles in the dust samples and classified them into 9 types based on morphology and composition. We observed a broad range of morphologies for these FR-containing particles, suggesting FR transfer to dust via multiple mechanisms. We developed an equation to describe the heterogeneity of FR-containing particles in environmental dust samples. The number of individual FR-containing particles expected in a 1-mg dust sample with a FR concentration of 100. ppm ranged from <. 1 to >. 1000 particles. The presence of rare, high-concentration bromine particles was correlated with decabromodiphenyl ether concentrations obtained via GC-MS. When FRs are distributed heterogeneously in highly concentrated dust particles, human exposure to FRs may be characterized by high transient exposures interspersed by periods of low exposure, and GC-MS FR concentrations may exhibit large variability in replicate subsamples. Current limitations of this SEM/EDS technique include potential false negatives for volatile and chlorinated FRs and greater quantitation uncertainty for brominated FR in aluminum-rich matrices. © 2013 Elsevier Ltd.

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