Groups Of Semi-volatile Organic Compounds Research Articles

71 Metabolomics Study of a Lung Model Exposed to Different Ultrafine Particles (UFP) Aerosols

Abstract Ultrafine particles (UFP), diameter of <0.1 µm, contribute to urban particulate air pollution. There is still not much evidence on their effects on humans. Our study aims to address their possible effects on lung metabolome. Alveolar epithelial cells (A549) together with macrophages (THP-1) were seeded on the apical side of the insert membrane, and fibroblasts (MRC-5) on the downside, respectively. Triple cell cultures were exposed at the air liquid interface to different aerosols generated by a combustion aerosol standard (CAST) soot generator. Applied aerosols consisted of UFP with either high or low content of semi-volatile organic compounds (SVOC). Herein, apical cell lysates were extracted for metabolites. Data acquisition was performed by GC-MS and processed with R and then analyzed by MetaboAnalyst. Statistical analysis showed that top features differentiating the high SVOC from clean air controls were amino acids (L-tryptophan and L-lysine), whereas for low SVOC, 5-methylthioadenosine and 5-methoxyindoleacetate. Tryptophan and its metabolite 5-hydroxy- tryptophan were significantly upregulated in high SVOC. However, in low SVOC, 5-methoxyindoleacetate was substantially upregulated. Pathway analysis revealed that purine metabolism was between the top significant enriched pathways in both high and low SVOC groups. Moreover, tryptophan metabolism which modulates immunity and inflammation was enriched similarly in both groups. These findings suggest that lung cell metabolome is modulated distinctively based on the chemical identity of UFP, which could give more understanding about the lung response mechanism to inhaled UFP. This work was funded by Bayerische Staatsministeriums für Umwelt und Verbraucherschutz (BayUFP).

The effect of reduction measures on concentrations of hazardous semivolatile organic compounds in indoor air and dust of Swedish preschools.

Young children spend a substantial part of their waking time in preschools. It is therefore important to reduce the load of hazardous semivolatile organic compounds (SVOCs) in the preschools' indoor environment. The presence and levels of five SVOC groups were evaluated (1) in a newly built preschool, (2) before and after renovation of a preschool, and (3) in a preschool where SVOC-containing articles were removed. The new building and the renovation were performed using construction materials that were approved with respect to content of restricted chemicals. SVOC substance groups were measured in indoor air and settled dust and included phthalates and alternative plasticizers, organophosphate esters (OPEs), brominated flame retardants, and bisphenols. The most abundant substance groups in both indoor air and dust were phthalates and alternative plasticizers and OPEs. SVOC concentrations were lower or of the same order of magnitude as those reported in comparable studies. The relative Cumulative Hazard Quotient (HQcum ) was used to assess the effects of the different reduction measures on children's SVOC exposure from indoor air and dust in the preschools. HQcum values were low (1.0-6.1%) in all three preschools and decreased further after renovation and article substitution. The SVOCs concentrations decreased significantly more in the preschool renovated with the approved building materials than in the preschool where the SVOC-containing articles were removed.

Slopes and intercepts from log-log correlations of gas/particle quotient and octanol-air partition coefficient (vapor-pressure) for semi-volatile organic compounds: II. Theoretical predictions vs. monitoring

The logarithm of gas/particle (G/P) partition quotient (logKP) has been found to have a linear relationship with logKOA (octanol-air partition coefficient) with slope mo and intercept bo and logPL (subcooled liquid vapor pressure) with slope mp and intercept bp. In the sister paper of the present work, analytical equations to predict the slope mo and intercept bo based on logKOA and predict the slope mp and intercept bp based on logPL are developed using steady state theory. In this work, the equations are evaluated using world-wide monitoring data (262 pairs for mo and bo values and 292 pairs for mp and bp values produced from more than 10,000 monitiring data worldwide) for selected seven groups of semi-volatile organic compounds (SVOCs), including polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins and polychorinated dibenzofurans (PCDD/Fs), polyclorinated biphenyl (PCBs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated naphthalenes (PCNs), organochlorinated pesticides (OCPs), novel brominated flame retardants (NBFRs), and other selected halogenated flame retardants. The slopes and intercepts predicted by the steady state equations reproduce the trends observed in monitoring regression results for the seven SVOC groups, with 44.4% of the variation of monitoring mo values accounted for by logKOA and 48.2% of the variation of monitoring mp values accounted for by logPL. Theoretically, the values of mo can be any value between 0 and 1 dependent on the values of KOA, and are not constrained to 1 as in equilibrium theory. Likewise, the values of mp can be any value between 0 and -1 dependent on the values of PL, and not constrained to −1 predicted by the equilibrium theory. The influence of sampling artifacts on the G/P partitioning of SVOCs has most likely been overemphasized by the equilibrium theory. Thus, the equilibrium approach should be abandoned in favor of the steady state approach for calculating the G/P partition quotients for SVOCs with high KOA values (>1011.38) or low PL values (<10−4.92).

Legacy and emerging organophosphorus flame retardants and plasticizers in indoor microenvironments from Guangzhou, South China

Indoor dust has been extensively used for assessment of indoor contamination, especially for semi-volatile organic compounds (SVOCs). In the present study, the occurrence of four groups of SVOCs, i.e. organophosphorus flame retardants (PFRs), emerging PFRs (ePFRs), legacy phthalates (LPs), and alternative plasticizers (APs), was investigated in the indoor dust and air collected from floors, table surfaces, windows, and air conditioner (A/C) filters in bedrooms and offices in Guangzhou, South China. In bedrooms, A/C filter dust showed the highest median concentrations of PFRs (4670 ng/g) and ePFRs (586 ng/g), whilst the highest median concentrations of LPs and APs were found in floor (240,880 ng/g) and window dust (157,160 ng/g), respectively. In offices, A/C filter dust showed the highest median concentrations for PFRs (6750 ng/g) and APs (504,520 ng/g), while the highest ePFR median level was found in PC table dust (5810 ng/g) and LPs in floor dust (296,270 ng/g). Median air concentrations of PFRs, ePFRs, LPs, and APs were measured at 4.6, 0.12, 399, and 25 ng/m3 in bedrooms, and at 8.0, 0.05, 332, and 43 ng/m3 in offices, respectively. Tris(1-chloro-iso-propyl) phosphate (TCIPP) was the predominant PFRs/ePFRs in both dust and air. Di(2-ethylhexyl) phthalate (DEHP), di-iso-decyl phthalate (DIDP) and di-iso-nonyl phthalate (DINP) were the main LP/AP compounds in dust, whilst di-iso-butyl phthalate (DIBP) and di-n-butyl phthalate (DNBP) were the most abundant LPs/APs in air. A significant correlation (p < 0.05) was found between dust and air levels for chemicals with log Koa < 14, indicating that equilibrium was achieved for these chemicals but not for those with log Koa > 14. Among the investigated human exposure pathways (i.e. dust ingestion, dermal absorption, and air inhalation), dust ingestion was the predominant one for all chemicals. Human exposures of this magnitude to these chemicals through the investigated pathways was unlikely to present a health risk in the present study.

Legacy and emerging semi-volatile organic compounds in sentinel fish from an arctic formerly used defense site in Alaska

The Arctic is subject to long-range atmospheric deposition of globally-distilled semi-volatile organic compounds (SVOCs) that bioaccumulate and biomagnify in lipid-rich food webs. In addition, locally contaminated sites may also contribute SVOCs to the arctic environment. Specifically, Alaska has hundreds of formerly used defense (FUD) sites, many of which are co-located with Alaska Native villages in remote parts of the state. The purpose of this study was to investigate the extent of SVOC contamination on Alaska’s St. Lawrence Island through the analysis of sentinel fish, the ninespine stickleback (Pungitius pungitius), collected from Troutman Lake located within the watershed of an FUD site and adjacent to the Yupik community of Gambell. We measured the concentrations of legacy and emerging SVOCs in 303 fish samples (81 composites), including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs) and their diester metabolites, and per- and poly-fluoroalkyl substances (PFAS). PBDEs and PCBs were the most abundant SVOC groups found in stickleback with ΣPBDE and ΣPCB median concentrations of 25.8 and 10.9 ng/g ww, respectively, followed by PFAS (median ΣPFAS 7.22 ng/g ww). ΣOPE and ΣOPE metabolite concentrations were lower with median concentrations of 4.97 and 1.18 ng/g ww, respectively. Chemical patterns and distributions based on correlations and comparison with SVOC concentrations in stickleback from other parts of the island suggest strong local sources of PCBs, PBDEs, and PFAS on St. Lawrence Island.

Linking past uses of legacy SVOCs with today's indoor levels and human exposure

Semivolatile organic compounds (SVOCs) emitted from consumer products, building materials, and indoor and outdoor activities can be highly persistent in indoor environments. Human exposure to and environmental contamination with polychlorinated biphenyls (PCBs) was previously reported in a region near a former PCB production facility in Slovakia. However, we found that the indoor residential PCB levels did not correlate with the distance from the facility. Rather, indoor levels in this region and those reported in the literature were related to the historic PCB use on a national scale and the inferred presence of primary sources of PCBs in the homes. Other SVOCs had levels linked with either the activities in the home, e.g., polycyclic aromatic hydrocarbons (PAHs) with wood heating; or outdoor activities, e.g., organochlorine pesticides (OCPs) with agricultural land use and building age. We propose a classification framework to prioritize SVOCs for monitoring in indoor environments and to evaluate risks from indoor SVOC exposures. Application of this framework to 88 measured SVOCs identified several PCB congeners (CB-11, -28, -52), hexachlorobenzene (HCB), benzo(a)pyrene, and γ-HCH as priority compounds based on high exposure and toxicity assessed by means of toxicity reference values (TRVs). Application of the framework to many emerging compounds such as novel flame retardants was not possible because of either no or outdated TRVs. Concurrent identification of seven SVOC groups in indoor environments provided information on their comparative levels and distributions, their sources, and informed our assessment of associated risks.

Analysis of brominated and chlorinated flame retardants, organophosphate esters, and polycyclic aromatic hydrocarbons in silicone wristbands used as personal passive samplers

For the first time, we present an analytical method to simultaneously extract, fractionate, and quantify four groups of semi-volatile organic compounds (SVOCs) in silicone wristbands, including 35 polybrominated diphenyl ethers (PBDEs), 10 novel flame retardants (NFRs), 19 organophosphate esters (OPEs), and 13 polycyclic aromatic hydrocarbons (PAHs). Wristbands were extracted using ultrasonication, and cleaned and fractionated on two multi-layer columns: one consisting of neutral alumina, neutral silica and Florisil, and the other consisting of neutral alumina, neutral silica, and acidic silica. Method accuracy and precision were validated using spiked wristband samples (n = 8) and procedural blanks (n = 7). Average matrix spike percent recoveries for all target analytes were within 57–107% with relative standard errors < 20%, with a few exceptions. This method was applied to analyze thirteen wristbands worn by ten participants for seven days; three participants wore two wristbands to evaluate duplicate samples. Percent recoveries of surrogate standards for all four groups of analytes in these wristbands were all within the 80–120% range with a few exceptions: recoveries for 13C12BDE-209 and for 13C12-triphenyl phosphate ranged from 35 to 62% and 69–176%, respectively. The majority of target analytes were detected in at least half of worn wristbands. The levels of total PBDEs, NFRs, OPEs and PAHs in deployed wristbands ranged from 28.4 to 412 ng, 40.7 to 625 ng, 2440 to 9580 ng, and 76.2 to 1240 ng, respectively.

Polydimethylsiloxane (silicone rubber) brooch as a personal passive air sampler for semi-volatile organic compounds

Exposure assessments conducted using a personal sampler include the contribution of human activities to exposure that is neglected when using a stationary air sampler. This study evaluated the uptake characteristics and application of the polydimethylsiloxane (PDMS or silicone rubber) brooch as a personal passive air sampler (PPAS) for measuring concentrations of two groups of semi-volatile organic compounds (SVOCs), namely phthalates and organophosphate esters (OPEs), indoors in proximity to the breathing zone.Uptake rates of the PDMS brooch were calibrated against a personal low volume active air sampler (PLV-AAS) co-deployed on each of five study participants working in offices for 8 hs daily for four days. Sampling rates measured here ranged from 0.41 ± 0.33 to 1.33 ± 0.34 m3 day−1 dm−2 with an average value of 0.86 ± 0.29 m3 day−1 dm−2.Personal air concentrations of 1211 to 2640 ng m−3 for ∑5 phthalates and 254 to 663 ng m−3 for ∑5 OPEs were measured for three study participants who used the PDMS brooches continuously for seven days. These concentrations resulted in estimated inhalation exposures of 19,400 to 42,400 ng day−1 for ∑5 phthalates and 4,070 to 10,600 ng day−1 for ∑5 OPEs.This study demonstrated that the PDMS brooch can be used to assess inhalation exposure when worn for at least 24 h indoors, for compounds present in >4 ng m−3 in air such as individual phthalates and OPEs tested here.

A pilot study on semivolatile organic compounds in senior care facilities: Implications for older adult exposures

The occurrence of five groups of semivolatile organic compounds (SVOCs) (total of ∼120 distinct chemicals) was investigated in senior care facilities in the United States and in Portugal. Indoor settled dust samples were collected from fourteen facilities, and the concentrations of organophosphate esters (OPEs), brominated flame retardants (BFRs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) were measured in these samples. Overall, OPEs, PAHs, and BFRs were the most abundant, and OCPs and PCBs were the least abundant SVOC groups in dust collected from both U.S. and Portuguese facilities. ∑OPE, ∑PAH, and ∑BFR concentrations were significantly higher in U.S. facilities than those in Portuguese facilities (P < 0.001), while ∑OCP and ∑PCB concentrations were not different between the two countries (P < 0.05). The samples were collected from three different microenvironments, including bedrooms, living rooms, and corridors. ∑OPE, ∑PAH, and ∑BFR concentrations were up to five times higher in corridors compared to bedrooms and living rooms. ∑OCP and ∑PCB concentrations were overall higher in bedrooms and in living rooms and lower in corridors.

The evolution of pollution profile and health risk assessment for three groups SVOCs pollutants along with Beijiang River, China.

Three important groups of semi-volatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), organic chlorinated pesticides (OCPs) and phthalate esters (PAEs), were produced by various human activities and entered the water body. In this study, the pollution profiles of three species including 16 PAHs, 20 OCPs and 15 PAEs in water along the Beijiang River, China were investigated. The concentrations of Σ16PAHs in the dissolved and particulate phases were obtained as 69-1.5×102 ng L-1 and 2.3×103-8.6×104 ngg-1, respectively. The levels of Σ20OCPs were 23-66ng L-1 (dissolved phase) and 19-1.7×103 ngg-1 (particulate phase). Nevertheless, higher levels of PAEs were found both in the dissolved and particulate phases due to abuse use of plastic products. Furthermore, non-cancer and cancer risks caused by these SVOCs through the ingestion absorption and dermal absorption were also assessed. There was no non-cancer risk existed through two kinds of exposure of them at current levels, whereas certain cancer risk existed through dermal absorption of PAHs in the particulate phase in some sampling sites. The results will show scientific insights into the evaluation of the status of combined pollution in river basins, and the determination of strategies for incident control and pollutant remediation.

Spatial distributions, source apportionment and ecological risk of SVOCs in water and sediment from Xijiang River, Pearl River Delta.

Xijiang River is an important drinking water source in Guangxi Province, China. Along the Xijiang River and surrounding tributary, the pollution profile of three important groups of semi-volatile organic compounds, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and phthalate esters (PAEs), was analyzed. Relatively low levels of PAHs (64-3.7×102ngL-1) and OCPs (16-70ngL-1), but high levels of PAEs (7.9×102-6.8×103ngL-1) occurred in the water. Comparatively, low levels of OCPs (39-1.8×102ngg-1) and PAEs (21-81ngg-1), but high levels of PAHs (41-1.1×103ngg-1) were found in sediment. Principal component analyses for source identification indicated petroleum-derived residues or coal and biomass combustion, and vehicular emission was the main sources for PAHs. The OCPs sources of each category were almost independent, whereas the new input of HCHs and p,p'-DDTs probably existed in some areas. PAEs were mainly originated from personal care products of urban sewage, plastic and other industrial sources. Ecological risk through the risk quotient analysis indicated a small or significant potential adverse effect on fish, daphnia and green algae. Nevertheless, the integrated risk of all pollutants should be taken into account in future study.

National investigation of semi-volatile organic compounds (PAHs, OCPs, and PCBs) in lake sediments of China: Occurrence, spatial variation and risk assessment.

In this study, a large scale investigation of semi-volatile organic compounds (SVOCs) in sediments from 52 lakes, located in five geographic regions across China, was conducted to assess sediment quality in terms of organic contaminants. Concentrations of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) in sediment were found to range between 17.00-6,633, 0.12-45.24, and 0.03-13.99ngg-1, respectively. Lake sediments from different regions exhibited variation in contamination levels, and in the compositions of isomers. The descending order of contamination levels for the three SVOCs groups (i.e., ∑PAHs, ∑OCPs, ∑PCBs) were as follows: the eastern plain region (EPR)>the Yunnan-Guizhou plateau (YGP)>the northeast China region (NCR)>the Qinghai-Tibet plateau (QTP)>the Mongolia-Xinjiang plateau (MXP). High molecular weight PAHs, OCPs and PCBs were found at high concentrations in parts of the EPR and YGP, while lighter isomers were likely to be atmospherically transported, resulting in their nationwide distribution. The sources and type variation (local input or atmospheric deposition) are the primary controls of spatial variation. Additionally, human related socio-economic factors, and geographic conditions also played important roles in influencing the spatial differentiation. According to simple sediment quality guidelines (SQG), the risks posed by PCBs in sediments were not as serious as those posed by PAHs and DDT.

Optimisation steps of an innovative air sampling method for semi volatile organic compounds

This work describes optimisation steps of an innovative method for the measurement several groups of semi-volatile organic compounds (SVOCs) in air, collecting both gaseous and particulate air fractions. It is based on active air sampling on sorption tubes (consisting of polydimethylsiloxane (PDMS) and Tenax TA), followed by thermal desorption and gas chromatography mass spectrometry analysis (TD–GC–MS). The optimised method was validated in the laboratory for the measurement of selected target compounds from the following chemical classes: polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and phthalate esters (PEs). It was applied in different Belgian urban outdoor as well as indoor environments. The new method is characterised by limits of detection in the range of 0.003–0.3 ng m−3 for PAHs, 0.004–0.2 ng m−3 for PCBs, 0.113–0.201 ng m−3 for PBDEs and 0.002–0.2 ng m−3 for PEs, a linearity of 0.996 and a repeatability of less than 10% for all studied compounds.

Evidence of Bias in Air−Water Henry's Law Constants for Semivolatile Organic Compounds Measured by Inert Gas Stripping

Accurate knowledge of the air-water Henry's law constant (H) is crucial for understanding an organic compound's environmental behavior. The inert gas stripping (IGS) method, widely used to measure H of semivolatile organic compounds (SOCs), may yield erroneously high values for compounds with a high water surface adsorption coefficient, K(IA), because chemical adsorbed to the bubble surface may be transferred to the head space upon bursting at the top of the stripping column. Experiments with alkanols of variable chain length identified a K(IA) threshold of approximately 10(-3) m, above which IGS is susceptible to this artifact. Most SOCs are predicted to have K(IA) values well above that threshold. IGS-determined H-values for chemicals belonging to various groups of SOCs were evaluated by comparison with H-values either calculated from reliable vapor pressure and solubility data or derived from data compilations that achieve thermodynamic consistency through optimized adjustment of measured physical-chemical property data. The investigated deviations were found to be generally consistent with what would be expected from a surface adsorption artifact. Namely, the apparent bias in IGS-determined H-values, if it occurs, (1) is positive, (2) increases with increasing size of an SOC, and (3) increases with decreasing temperature. It generally is also of a magnitude predicted using estimated K(IA) values. However, different studies display different K(IA) threshold values, beyond which the artifact becomes notable, and some studies appear to succeed in avoiding the artifact altogether. Whereas the use of aerosol traps cannot explain the absence of a surface adsorption artifact, it may be related to higher flow rates used by some investigators. For large compounds or those with more than one functional group, the predicted deviation is too large when compared to observations, suggesting that the estimated K(IA) values for those compounds are too high. A full quantitative understanding of the artifact requires more accurate predictions of the adsorption of SOCs to the water surface.

Capillary microextraction for simultaneous analysis of multi-residual semivolatile organic compounds in water

Capillary microextractor (CME) in combination with a gas chromatograph-mass spectrometer (GC-MS) was employed for the determination of trace priority hazardous substances in water. Three groups of semivolatile organic compounds (SVOCs), i.e., chlorinated hydrocarbons, pesticides and polycyclic aromatic hydrocarbons (PAHs), were simultaneously determined. SVOCs were extracted from 7 mL of water samples on a 100 cm commercial gas chromatographic column (0.32 mm id x film thickness 0.25 microm, HP-5 capillary column) and eluted with only 3 microL of acetonitrile. The extractant was analyzed by GC-MS in the selected ion monitoring mode. The method showed good linearity over the concentration range 10 ng L(-1) to 3.0 mg L(-1) with correlation coefficients (r) greater than 0.99 and low limits of detection ranged from 10 ng L(-1) to 1.0 mg L(-1). High recovery (more than 80%) was obtained with relative standard deviation less than 10%. The method was successfully applied for trace level analyses of SVOCs in water samples.

Deposition of Polybrominated Diphenyl Ethers, Polychlorinated Biphenyls, and Polycyclic Aromatic Hydrocarbons to a Boreal Deciduous Forest

The atmospheric deposition of several groups of semi-volatile organic compounds to a deciduous forest in Canada was determined using an indirect technique based on ratios of measured canopy interception and air concentrations. Air (gas and particle phase) and bulk deposition were sampled for 14 months from October 2001 to December 2002 at both a forest and a nearby clearing, and extracts were quantified for polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Long-term average dry deposition velocities for vapors and particle-bound species were then derived for the canopy growing period. The mean dry gaseous deposition velocity for PBDEs and PCBs to the Canadian deciduous forest was 2.7 +/- 0.52 cm x s(-1), which is similar to the only other measured value for a deciduous canopy. Particle-bound deposition velocities to the canopy due to diffusion and impaction were 0.8 cm x s(-1) for the PBDEs and 0.11 cm x s(-1) for the PAHs. Differences in the particle-bound deposition velocities between PBDEs and PAHs and between deciduous canopies in Canada and Germany are explainable by differences in particle size distribution. The interception/concentration ratios for several PAHs were too low to be interpretable as dry gaseous deposition velocities. This is likely because the measured deposition flux under the canopy was less than the deposition flux to the canopy, possibly as a result of photodegradation in the canopy. From the ratio of canopy interception and average gas-phase concentration of less chlorinated PCBs, a predictive relationship between the canopy/air partition coefficient KPA and the octanol/air partition coefficient KOA was derived (KPA = 110 KOA0.67). Despite differences in local climate and canopy composition and structure, the deposition velocities and the canopy uptake capacity measured in Canada were remarkably similar to those reported in Germany, lending credibility to the suggestion that high gaseous deposition velocities are common throughout boreal and temperate deciduous forests. These extraordinarily high deposition velocities of semi-volatile organic compounds to deciduous forest canopies are at the core of the hypothesis of a significant filter effect of forests on a regional and global scale.