Association between Urinary Metabolite Levels of Organophosphorus Flame Retardants and Serum Sex Hormone Levels Measured in a Reference Sample of the US General Population.

Use of organophosphorus flame retardants (OPFRs) in consumer materials have led to widespread human exposure.Research is needed to examine the health effects attributable to the general population's exposure to OPFRs. Using the data from the National Health and Nutrition Examination Surveys (NHANES) (2013-2014), multiple regression analyses were performed to compare the adjusted geometric means (aGMs) of serum sex hormone by quartiles of urinary metabolites of OPFRs, including diphenyl phosphate (DPhP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), bis(2-chloroethyl) phosphate (BCEP) and dibutyl phosphate(DBuP), in children (6 - 9 years old), adolescents (10 - 19 years old) and adults(≥ 20 years old), while accounting for potential confounding factors.

Emerging Chemicals of Health Concern in Electronic Nicotine Delivery Systems.

Electronic nicotine delivery systems (ENDS), by virtue of their highly engineered construction (plastics, glass, e-liquids), may contain a number of emerging chemicals of concern (ECCs), including phthalates, phenolic compounds, and flame retardants. Current knowledge regarding the safety of ENDS may underestimate the health risks from ECCs. In this study, we examined the types and levels of those three groups of chemicals in the components and parts of ENDS devices, including refill liquids, tanks/cartridges, atomizers, drip tips/mouthpieces, and sealing materials.

Use of Electronic Cigarettes in Smoke-Free Spaces by Smokers: Results from the 2014-2015 Population Assessment on Tobacco and Health Study.

: Smoke-free air policies exist to protect users and nonusers from exposure to tobacco smoke. Although electronic nicotine delivery systems (ENDS) may expose passerby to nicotine and particulate matter, few US states regulate indoor use of ENDS. The purpose of this study was to investigate reported rationales for ENDS use and reported ENDS use in public smoke-free places by dual cigarette/ENDS users.

Modes of delivery in concurrent nicotine and cannabis use ("co-use") among youth: Findings from the International Tobacco Control (ITC) Survey.

Cannabis use is more common among nicotine users than non-users. This study characterized concurrent use of nicotine and cannabis ("co-use") among 12,064 youth aged 16-19 years residing in Canada, the United States, and England in 2017. : Data were from the ITC Youth Tobacco & Vaping Survey (Wave 1).

Concurrent Quantification of Emerging Chemicals of Health Concern in e-Cigarette Liquids by High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

Emerging chemicals of concern (ECCs), including phthalate plasticizers, flame retardants, and phenolic compounds, are likely present in electronic nicotine delivery system (ENDS) replacement solutions (e-liquids) which are often packaged, stored in, and/or can contact with, plastic, glass, and metal materials. Developing and validating an efficient analytical method for concurrent quantification of ECCs in e-liquids are thus needed to inform evidence-based safety evaluation of ENDS products. In this study, we developed and validated a "dilute-and-shoot" method using high-performance liquid chromatography coupled with tandem mass spectrometry to simultaneously measure organophosphate flame retardants (OPFRs), phthalate plasticizers, and tetrabromobisphenol A (TBBPA) in e-liquids.

Nicotine and Toxicant Exposure Among Concurrent Users (Co-Users) of Tobacco and Cannabis.

Background: Smoking cannabis may potentially increase exposure to numerous toxic chemicals that are commonly associated with tobacco use. There is a paucity of data related to toxicant exposures among concurrent users of tobacco and cannabis (co-users).

Methods: Data are from the Population Assessment of Tobacco and Health Study Wave 1 Biomarker Restricted-Use Files.

Marijuana and Tobacco Coexposure in Hospitalized Children.

Background: The impact of secondhand marijuana smoke exposure on children is unknown. New methods allow for the detection of marijuana smoke exposure in children.

Methods: We studied children who were hospitalized in Colorado and had a parent participating in a smoking cessation study; all children had urine samples remaining from the original study as well as consent for future research.

Examining the Association between Body Burdens of Harmful Chemicals and Heaviness of Marijuana Smoking.

Marijuana is seeing increased use both globally and domestically. However, the scientific community has not fully reached a consensus about what negative health effects and to what extent marijuana smoking may cause. In this study, we evaluated the associations between the body burdens of polycyclic aromatic hydrocarbons (PAHs) among marijuana smokers and the smoking heaviness.

Urinary Metabolite Levels of Flame Retardants in Electronic Cigarette Users: A Study Using the Data from NHANES 2013-2014.

Evaluating the safety of e-cigarettes and making informed judgement about developing potential standards require sufficient scientific evidence. Since e-cigarettes are highly engineered products containing plastic, glass and metal parts, and e-liquids are largely different matrices, many toxic compounds which are not typical hazards for the users of combustible tobacco products (e.g.

Brief Report: Lead Levels in Selected Electronic Cigarettes from Canada and the United States.

Few published studies have investigated the presence of lead in the e-liquid of electronic nicotine delivery systems (ENDS). Lead inhalation is associated with increased risk of stroke, heart disease, and other diseases. This study used a novel application of graphite furnace technology to compare the concentration of lead between e-liquids of different packaging and product designs using e-liquids that are or were commercially available in the United States and Canada.

Detecting biomarkers of secondhand marijuana smoke in young children.

Background: The impact of secondhand marijuana smoke exposure on children is unknown. New methods allow detection of secondhand marijuana smoke in children.

Methods: We studied children ages 1 mo to 2 y hospitalized with bronchiolitis in Colorado from 2013 to 2015.

Temporal Trends of Secondhand Smoke Exposure: Nonsmoking Workers in the United States (NHANES 2001-2010).

Background: The workplace is one of the major locations outside of the home for nonsmokers' exposure to secondhand smoke (SHS). New policies in many U.S.

Sensitive Quantification of Cannabinoids in Milk by Alkaline Saponification-Solid Phase Extraction Combined with Isotope Dilution UPLC-MS/MS.

Maternal exposure to marijuana during the lactation period-either active or passive-has prompted concerns about transmission of cannabinoids to breastfed infants and possible subsequent adverse health consequences. Assessing these health risks requires a sensitive analytical approach that is able to quantitatively measure trace-level cannabinoids in breast milk. Here, we describe a saponification-solid phase extraction approach combined with ultra-high-pressure liquid chromatography-tandem mass spectrometry for simultaneously quantifying Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) in breast milk.

Urinary concentrations of PAH and VOC metabolites in marijuana users.

Background: Marijuana is seeing increased therapeutic use, and is the world's third most-popular recreational drug following alcohol and tobacco. This widening use poses increased exposure to potentially toxic combustion by-products from marijuana smoke and the potential for public health concerns.

Objectives: To compare urinary metabolites of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) among self-reported recent marijuana users and nonusers, while accounting for tobacco smoke exposure.

Analysis of Cannabinoids and Their Metabolites in Human Urine.

Biologically monitoring marijuana exposure from active and passive use requires both a wide linear range and sensitive detection. We have developed and validated a multifunctional method using ultrahigh performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) for analysis of urinary Δ9-tetrahydrocannabinol (THC), cannabidiol and cannabinol, and two major metabolites of THC, 11-nor-9-carboxy-THC and 11-hydroxy-THC, in active users and particularly in people exposed to secondhand marijuana smoke (SHMS). The method used positive electrospray ionization (ESI) mode to reach the sensitivity needed to detect trace SHMS exposure with limits of detection (LOD) ranging from 0.

Assessing exposure to tobacco-specific carcinogen NNK using its urinary metabolite NNAL measured in US population: 2011-2012.

Carcinogenic tobacco-specific nitrosamines (TSNAs) such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) are found only in tobacco and derived products. Food and Drug Administration of the United States (US FDA) lists NNK as one of the 93 harmful and potentially harmful constituents (HPHCs) found in tobacco products and tobacco smoke. The aim of this study was to use the urinary concentration of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a major metabolite of NNK, to quantitatively estimate exposure to NNK in the US general population.

Validation of a LC-MS/MS method for quantifying urinary nicotine, six nicotine metabolites and the minor tobacco alkaloids--anatabine and anabasine--in smokers' urine.

Tobacco use is a major contributor to premature morbidity and mortality. The measurement of nicotine and its metabolites in urine is a valuable tool for evaluating nicotine exposure and for nicotine metabolic profiling--i.e.

A high-throughput robotic sample preparation system and HPLC-MS/MS for measuring urinary anatabine, anabasine, nicotine and major nicotine metabolites.

Background: Most sample preparation methods characteristically involve intensive and repetitive labor, which is inefficient when preparing large numbers of samples from population-scale studies.

Methods: This study presents a robotic system designed to meet the sampling requirements for large population-scale studies. Using this robotic system, we developed and validated a method to simultaneously measure urinary anatabine, anabasine, nicotine and seven major nicotine metabolites: 4-Hydroxy-4-(3-pyridyl)butanoic acid, cotinine-N-oxide, nicotine-N-oxide, trans-3'-hydroxycotinine, norcotinine, cotinine and nornicotine.

Computational fluid dynamics modeling of transport and deposition of pesticides in an aircraft cabin.

Spraying of pesticides in aircraft cabins is required by some countries as part of a disinsection process to kill insects that pose a public health threat. However, public health concerns remain regarding exposures of cabin crew and passengers to pesticides in aircraft cabins. While large scale field measurements of pesticide residues and air concentrations in aircraft cabins scenarios are expensive and time consuming, Computational Fluid Dynamics (CFD) models provide an effective alternative for characterizing concentration distributions and exposures.

Studying permethrin exposure in flight attendants using a physiologically based pharmacokinetic model.

Assessment of potential health risks to flight attendants from exposure to pyrethroid insecticides, used for aircraft disinsection, is limited because of (a) lack of information on exposures to these insecticides, and (b) lack of tools for linking these exposures to biomarker data. We developed and evaluated a physiologically based pharmacokinetic (PBPK) model to assess the exposure of flight attendants to the pyrethroid insecticide permethrin attributable to aircraft disinsection. The permethrin PBPK model was developed by adapting previous models for pyrethroids, and was parameterized using currently available metabolic parameters for permethrin.

Exposure of flight attendants to pyrethroid insecticides on commercial flights: urinary metabolite levels and implications.

Pyrethroid insecticides have been used for disinsection of commercial aircrafts. However, little is known about the pyrethroids exposure of flight attendants. The objective of the study was to assess pyrethroids exposure of flight attendants working on commercial aircrafts through monitoring the urinary pyrethroids metabolite levels.

QSPR-based prediction of gas/particle partitioning of polychlorinated biphenyls in the atmosphere.

By reviewing the existing models for describing gas/particle partitioning of semi-volatile organic compounds in the atmosphere, it was assumed that gas/particle partition coefficient, expressed as Kp, may be predicted using molecular descriptors. Overall 14 molecular descriptors of each compound calculated using semi-empirical method parametric model 3 (PM3) were tested against logKp of selected PCBs to determine the best ones governing partitioning. Eight descriptors molecular weight (Mw), molecular volume (Mv), total energy (TE), electronic energy (EE), squared atom electron densities on carbon, hydrogen and chlorine atoms in a given molecule (Summation qC2, Summation qCl2, Summation qH2) and average molecular polarizability (alpha m) were found to be highly correlated with logKp compared to other molecular descriptors.