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Flame retardants (FRs) are used in many consumer products for fire safety reasons. Their use in children’s car seats may result in children’s and vehicle occupants’ exposure to these compounds including inhalation exposure through poor vehicle air quality. We have tested several children’s car seats from local retailers for the presence of FRs. A number of organophosphorus flame retardants (OPFRs) were identified in the extracts (dichloromethane) of eight foam materials taken from the seats. They included several organophosphates (triethyl phosphate (TEP) (detected in all 8 samples) followed by tris(butoxyethyl) phosphate (2), triphenyl phosphate (1), di-(t-butylphenyl) phenyl phosphate (1) butyl diethyl phosphate (1) and tris(4-tert-butylphenyl) phosphate (1)) and organophosphonates (two isomers of 5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate (PMMMP) (detected in 5 of the 8 samples) followed by diethyl ethylphosphonate (1) and 4-methoxy-2-methylbutyl ethyl butylphosphonate (1)). TEP was the most frequently detected among these OPFRs. Due to its relatively high vapour pressure (0.39 mm Hg at 25 °C) among detected OPFRs, TEP is most likely to emit into vehicle interior air during product use, which could result in inhalation exposure for the children using the car seat and other passengers. We therefore have tested the emission rate of TEP in a micro-chamber at 40 °C for estimating potential exposure of vehicle occupants. The emission profile shows the concentrations of TEP in the chamber reached a maximum within the first few hours and then decreased over time. There was a lack of correlation between 24-hour average emission rate and concentrations of TEP in the product. The exact health risk to children and other vehicle occupants in this case requires further research to quantify.

Abstract: Knowledge of biological reactivity and underlying toxicity mechanisms of airborne particulate matter (PM) is central to the characterization of the risk associated with these pollutants. An integrated screening platform consisting of protein profiling of cellular responses and cytotoxic analysis was developed in this study for the estimation of PM potencies. Mouse macrophage (J774A.1) and human lung epithelial cells (A549) were exposed in vitro to Ottawa urban particles (EHC6802) and two reference mineral particles (TiO2 and SiO2). Samples from the in vitro exposure experiment were tested following an integrated classical cytotoxicity/toxicoproteomic assessment approach for cellular viability (CellTiter Blue®, lactate dehydrogenase) and proteomic analyses. Cellular proteins were pre‐fractionated by molecular weight cut‐off filtration, digested enzymatically and were analyzed by matrix‐assisted laser desorption ionization–time‐of‐flight–time‐of‐flight–mass spectrometry for protein profiling and identification. Optimization of detergent removal, pre‐fractionation strategies and enzymatic digestion procedures led to increased tryptic peptide (m/z) signals with reduced sample processing times, for small total protein contents. Proteomic analyses using this optimized procedure identified statistically significant (P < 0.05) PM dose‐dependent changes at the molecular level. Ranking of PM potencies based on toxicoproteomic analysis were in line with classical cytotoxicity potency‐based ranking. The high content toxicoproteomic approach exhibited the potential to add value to risk characterization of environmental PM exposures by complementing and validating existing cytotoxicity testing strategies. [ABSTRACT FROM AUTHOR]

The likelihood of environmental and health impacts of silicon dioxide nanoparticles (SiNPs) has risen, due to their increased use in products and applications. The biological potency of a set of similarly-sized amorphous SiNPs was investigated in a variety of cells to examine the influence of physico-chemical and biological factors on their toxicity. Cellular LDH and ATP, BrdU incorporation, resazurin reduction and cytokine release were measured in human epithelial A549, human THP-1 and mouse J774A.1 macrophage cells exposed for 24 h to suspensions of 5–15, 10–20 and 12 nm SiNPs and reference particles. The SiNPs were characterized in dry state and in suspension to determine their physico-chemical properties. The dose-response data were simplified into particle potency estimates to facilitate the comparison of multiple endpoints of biological effects in cells. Mouse macrophages were the most sensitive to SiNP exposures. Cytotoxicity of the individual cell lines was correlated while the cytokine responses differed, supported by cell type-specific differences in inflammation-associated pathways. SiNP (12 nm), the most cytotoxic and inflammogenic nanoparticle had the highest surface acidity, dry-state agglomerate size, the lowest trace metal and organics content, the smallest surface area and agglomerate size in suspension. Particle surface acidity appeared to be the most significant determinant of the overall biological activity of this set of nanoparticles. Combined with the nanoparticle characterization, integration of the biological potency estimates enabled a comprehensive determination of the cellular reactivity of the SiNPs. The approach shows promise as a useful tool for first-tier screening of SiNP toxicity. [ABSTRACT FROM PUBLISHER]

Background: There is paucity of information on mechanisms constituting adverse birth outcomes. We assessed here the relationship between vascular integrity and adverse birth effects. Methods and results: Third trimester maternal plasma (n = 144) from the Maternal-Infant Research on Environmental Chemicals Study (MIREC) was analysed for vascular, inflammatory and oxidative stress markers by HPLC-fluorescence, protein array and EIA method. Analysis of the <25th and >75th percentile birth weight subgroups revealed markers associated with birth weight (ETs, MMP-9, VEGF, and 8-isoPGF-2α) and gestational age (ET-1, MMP-2, and VEGF). Conclusions: Mechanistic insights into adverse birth outcome pathways can be achieved by integrating information on multiple biomarkers, physiology using systems biology approach. [ABSTRACT FROM PUBLISHER]

While production of engineered carbon nanotubes (CNTs) has escalated in recent years, knowledge of risk associated with exposure to these materials remains unclear. We report on the cytotoxicity of four CNT variants in human lung epithelial cells (A549) and murine macrophages (J774). Morphology, metal content, aggregation/agglomeration state, pore volume, surface area and modifications were determined for the pristine and oxidized single-walled (SW) and multi-walled (MW) CNTs. Cytotoxicity was evaluated by cellular ATP content, BrdU incorporation, lactate dehydrogenase (LDH) release, and CellTiter-Blue (CTB) reduction assays. All CNTs were more cytotoxic than respirable TiO2 and SiO2 reference particles. Oxidation of CNTs removed most metallic impurities but introduced surface polar functionalities. Although slopes of fold changes for cytotoxicity endpoints were steeper with J774 compared to A549 cells, CNT cytotoxicity ranking in both cell types was assay-dependent. Based on CTB reduction and BrdU incorporation, the cytotoxicity of the polar oxidized CNTs was higher compared to the pristine CNTs. In contrast, pristine CNTs were more cytotoxic than oxidized CNTs when assessed for cellular ATP and LDH. Correlation analyses between CNTs' physico-chemical properties and average relative potency revealed the impact of metal content and surface area on the potency values estimated using ATP and LDH assays, while surface polarity affected the potency values estimated from CTB and BrdU assays. We show that in order to reliably estimate the risk posed by these materials, in vitro toxicity assessment of CNTs should be conducted with well characterized materials, in multiple cellular models using several cytotoxicity assays that report on distinct cellular processes. [ABSTRACT FROM AUTHOR]

There exists a knowledge gap in understanding potential toxicity of mesoporous silica nanoparticles. A critical step in assessing toxicity of these particles is to have a wide size range with different chemistries and physicochemical properties. There are several challenges when synthesizing mesoporous silica nanoparticles over a wide range of sizes including (1) nonuniform synthesis protocols using the same starting materials, (2) the low material yield in a single batch synthesis (especially for particles below 60- 70 nm), and (3)morphological instability during surfactant removal process and surface modifications. In this study, we synthesized a library of mesoporous silica nanoparticles with approximate particle sizes of 25, 70, 100, 170, and 600 nm. Surfaces of the silica nanoparticles were modified with hydrophilic-CH2-(CH2)2-COOH and relatively hydrophobic-CH2-(CH2)10-COOH functional groups. All silica nanoparticles were analysed for morphology, surface functionality, surface area/pore volume, surface organic content, and dispersion characteristics in liquid media. Our analysis revealed the synthesis of a spectrum of monodisperse bare and surface modified mesoporous silica nanoparticles with a narrow particle size distribution and devoid of cocontaminants critical for toxicity studies. Complete physicochemical characterization of these synthetic mesoporous silica nanoparticles will permit systematic toxicology studies for investigation of structure-activity relationships. [ABSTRACT FROM AUTHOR]

Abstract: Our earlier investigations on the chemical composition of biooils derived by the fast pyrolysis of chicken manure revealed the presence of more than 500 compounds. In order to simplify this heterogeneous and complex chemical system, we produced four biooil fractions namely strongly acidic fraction A, weakly acidic fraction B, basic fraction C and neutral fraction D on the basis of their solubilities in aqueous solutions at different pHs. The yield (wt/wt.%) for fraction A was 3%, for fraction B 21.3%, for fraction C 2.4% and for fraction D 32.4%, respectively. The four fractions were analyzed by elemental analyses, Fourier Transform infrared spectrophotometry (FTIR), 1H and 13C nuclear magnetic spectroscopy (NMR), and electrospray ionization mass spectrometry (ESI-MS). The major components of the four fractions were saturated and unsaturated fatty acids, N-heterocyclics, phenols, sterols, diols and alkylbenzenes. The pH separation system produced fractions of enhanced chemical homogeneity. [Copyright &y& Elsevier]

Abstract: MCM-41 silica whose pores have been expanded by post-synthesis hydrothermal treatment in the presence of N,N-dimethyldecylamine exhibits a unique combination of large pores (up to 20nm), pore volume (up to 3.5cc/g) and surface area (>1000m2/g). It was used to accommodate a large amount of amine groups (2.2mmol/g); thus generating a highly active base catalyst for Knoevenagel condensation. [Copyright &y& Elsevier]

Limited human exposure and toxicity data are currently available for 4,5,6,7-Tetrabromo-2,3-dihydro-1,1,3-trimethyl-3-(2,3,4,5-tetrabromophenyl)-1H-indene (OBTMPI), a flame retardant often used for high temperature application of various polymer materials. Levels of OBTMPI in a cohort population that includes children and their co-residing parents (n = 217) in Canada were determined. Detection frequency of OBTMPI in the samples was 22.6%. OBTMPI levels were in general at sub-to low ng/g lipid weight level with a 95th percentile at 15.6 ng/g lipid weight. Compared to an earlier study conducted in 2008–2009 in the same region, results from this study show an increase in both detection frequency and concentration of OBTMPI. In silico toxicity predictions using Multicase CaseUltra and Leadscope Model Applier suggested that OBTMPI, and its possible metabolites in humans, while unlikely to be carcinogenic or mutagenic, exhibit some estrogen antagonist, androgen antagonist and estrogen binding capability reflective of possible endocrine disrupting properties. Image 1 • Possible rise in levels of emerging flame retardant OBTMPI in humans in Canada. • Exposure to OBTMPI among child, mother and father living in the same household. • In silico prediction of endocrine disruption properties for OBTMPI and metabolites. Emerging flame retardant OBTMPI is present in humans and endocrine disruption predicted by in silico is a likely adverse effect of OBTMPI. [ABSTRACT FROM AUTHOR]

Controlled laboratory and field experiments were performed to collect volatile organic compounds (VOCs) emitted during drying of alfalfa. Laboratory experiments were conducted using a flow reactor method. Three drying temperatures of 60, 150 and 250°C with three drying times (5, 20 and 45min) were used to collect the VOCs. Field experiments were performed to validate the results obtained in the flow reactor method using a small-scale rotary drum dryer (operated at temperatures of 202, 345 and 480°C) and an industrial dehydration plant operated at temperatures of 800 to 1000°C. The exhaust gases collected during the drying process were subjected to a gas chromatography and mass spectrometry (GC–MS) analysis and the presence of a total of 48 VOCs was detected. The most common groups detected during alfalfa drying were alcohols, aldehydes, ketone, ester and unsaturated and saturated hydrocarbons. Drying temperature has a predominant effect on the number of VOCs emissions. The number of VOCs emitted increased with an increase in drying temperature. Drying time had an insignificant effect on the number of VOCs emitted, however, the intensity or concentration of compounds increased with an increase in drying time. The studies of different parts of the alfalfa plant revealed that a large group of the compounds present in one part (either leaf or stem) were absent in the other, although some compounds were present in all cases. Volatile organic compounds such as 1-octen-3-ol, (E)-3-hexen-1-ol and (E)-2-hexanal, were the most common compounds present in all parts of alfalfa plant. Sulphur compounds were present only in stems and may cause a potential problem for human health. The VOCs obtained from flowers are rich in alcohols and aldehydes. [Copyright &y& Elsevier]