Co-exposure of petrochemical workers to noise and mixture of benzene, toluene, ethylbenzene, xylene, and styrene: Impact on mild renal impairment and interaction.

Epidemiological evidence concerning effects of simultaneous exposure to noise and benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) on renal function remains uncertain. In 2020, a cross-sectional study was conducted among 1160 petrochemical workers in southern China to investigate effects of their co-exposure on estimated glomerular filtration rate (eGFR) and mild renal impairment (MRI). Noise levels were assessed using cumulative noise exposure (CNE). Urinary biomarkers for BTEXS were quantified. We found the majority of workers had exposure levels to noise and BTEXS below China's occupational exposure limits. CNE, trans, trans-muconic acid (tt-MA), and the sum of mandelic acid and phenylglyoxylic acid (PGMA) were linearly associated with decreased eGFR and increased MRI risk. We observed U-shaped associations for both N-acetyl-S-phenyl-L-cysteine (SPMA) and o-methylhippuric acid (2-MHA) with MRI. In further assessing the joint effect of BTEXS (ß, -0.164 [95% CI, -0.296 to -0.033]) per quartile increase in all BTEXS metabolites on eGFR using quantile g-computation models, we found SPMA, tt-MA, 2-MHA, and PGMA played pivotal roles. Additionally, the risk of MRI associated with tt-MA was more pronounced in workers with lower CNE levels (P = 0.004). Multiplicative interaction analysis revealed antagonisms of CNE and PGMA on MRI risk (P = 0.034). Thus, our findings reveal negative dose-effect associations between noise and BTEXS mixture exposure and renal function in petrochemical workers. With the exception of toluene, benzene, xylene, ethylbenzene, and styrene are all concerning pollutants for renal dysfunction. Effects of benzene, ethylbenzene, and styrene exposure on renal dysfunction were more pronounced in workers with lower CNE.

Effect of ionic strength on the assembly of simian vacuolating virus capsid protein around poly(styrene sulfonate).

Virus-like particles (VLPs) are noninfectious nanocapsules that can be used for drug delivery or vaccine applications. VLPs can be assembled from virus capsid proteins around a condensing agent, such as RNA, DNA, or a charged polymer. Electrostatic interactions play an important role in the assembly reaction. VLPs assemble from many copies of capsid protein, with a combinatorial number of intermediates. Hence, the mechanism of the reaction is poorly understood. In this paper, we combined solution small-angle X-ray scattering (SAXS), cryo-transmission electron microscopy (TEM), and computational modeling to determine the effect of ionic strength on the assembly of Simian Vacuolating Virus 40 (SV40)-like particles. We mixed poly(styrene sulfonate) with SV40 capsid protein pentamers at different ionic strengths. We then characterized the assembly product by SAXS and cryo-TEM. To analyze the data, we performed Langevin dynamics simulations using a coarse-grained model that revealed incomplete, asymmetric VLP structures consistent with the experimental data. We found that close to physiological ionic strength, [Formula: see text] VLPs coexisted with VP1 pentamers. At lower or higher ionic strengths, incomplete particles coexisted with pentamers and [Formula: see text] particles. Including the simulated structures was essential to explain the SAXS data in a manner that is consistent with the cryo-TEM images.

[Characteristics and Health Risk Assessment of BTESX in the Northern Suburbs of Nanjing].

AMA GC5000BTX was used to monitor the mixing ratio of benzene, toluene, ethylbenzene, m,p-xylene, o-xylene, and styrene (BTESX) in the atmosphere of the northern suburb of Nanjing from January 2014 to December 2016. The temporal variation characteristics of BTESX and the influence of meteorological elements on it were analyzed, and the characteristic ratio method (T/B) was used to qualitatively analyze the source of BTESX. Finally, the human exposure analysis and evaluation method of EPA was used to evaluate the health risk of BTESX. The results showed that during the observation period, the average mixing ratio of BTESX was (7.28±6.63)×10-9, and the mixing ratio of benzene was the highest at (2.45±3.91)×10-9. The mixing ratio of other species from large to small was toluene>ethylbenzene>m,p-xylene>o-xylene>styrene, which were (2.41±2.61)×10-9, (1.37±1.28)×10-9, (0.51±0.48)×10-9, (0.3±0.36)×10-9, and (0.22±0.42)×10-9, respectively. Due to the existence of stable aromatic sources, the monthly and seasonal variation in BTESX mixing ratio was not as obvious as that of other species (NOx, CO, SO2, PM2.5, etc.). The weekend effect of BTESX and other pollutants was not significant. The mixing ratio of BTESX was largely affected by the short distance transportation of chemical enterprises and traffic trunk roads in the northeast, resulting in a large mixing ratio of BTESX in the northeast. The mixing ratio of BTESX was jointly affected by relative humidity and temperature, and its high value area was mainly located in the range of 30%-70% relative humidity. In this range of relative humidity, the high value range of BTESX volume fraction increased with the elevation of temperature. The HI (hazard index) of BTESX in different seasons was within the safety range recognized by EPA, whereas the R (carcinogenic risk of benzene) value was higher than the safety threshold specified by EPA. At the same time, the HI and R values were higher in summer, to which great attention should be paid.

Occurrence of and dermal exposure to benzene, toluene and styrene found in hand sanitizers from the United States.

Human exposure to carcinogenic volatile organic compounds (VOCs), such as benzene, from hand sanitizers is a topic of current concern. In light of the heavy use of hand sanitizers during the COVID-19 pandemic, determination of exposure to toxicants present in these products deserves attention. The US Food and Drug Administration (FDA) had set an interim limit for benzene in alcohol-based hand sanitizers at 2000 parts-per-billion (ppb). We determined the concentrations of and exposure to three VOCs namely, benzene, toluene and styrene, in 200 hand sanitizers using high-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS). Benzene, toluene and styrene were found in 31%, 25% and 32%, respectively, of the samples analyzed at mean concentrations of 395 (range: 0.181-22,300), 164 (range: 0.074-20,700) and 61.3 ng/g (range: 0.082-4200 ng/g), respectively. Benzene was found at concentrations > 2000 ng/g (above the FDA interim limit) in 5% of the samples, representing 9 brands. The mean potential dermal exposure doses (DEDs) to benzene (children/teenagers: 34.6; adults: 24.7 ng/kg-bw/d) were higher than those for toluene (children/teenagers: 14.4; adults: 10.3 ng/kg-bw/d) and styrene (children/teenagers: 5.37; adults: 3.83 ng/kg-bw/d) in the 200 hand sanitizers analyzed. The estimated cancer risk from exposure to benzene in children/teenagers and adults from hand sanitizer use (at an estimated usage rate of 5 g/day) was greater than the one-in-a-million risk benchmark (1.0 × 10-6) for 10% and 9% of the samples, respectively. To the best of our knowledge, this is the first study to determine both the concentrations of and exposure risks to benzene, toluene and styrene present in hand sanitizers.

Evaluating commercial thermoplastic materials in fused deposition modeling 3D printing for their compatibility with DNA storage and analysis by quantitative polymerase chain reaction.

Nucleic acids are ubiquitous in biological samples and can be sensitively detected using nucleic acid amplification assays. To achieve highly accurate and reliable results, nucleic acid isolation and purification is often required and can limit the accessibility of these assays. Encapsulation of these workflows onto a single device may be achieved through fabrication methodologies featuring commercial three-dimensional (3D) printers. This study aims to characterize fused deposition modeling (FDM) filaments based on their compatibility with nucleic acid storage using quantitative polymerase chain reaction (qPCR). To study the adsorption of nucleic acids, storage vessels were fabricated using six common thermoplastics including: polylactic acid (PLA), nylon, acrylonitrile butadiene styrene (ABS), co-polyester (CPE), polycarbonate (PC), and polypropylene (PP). DNA adsorption of a short 98 base pair and a longer 830 base pair fragment to the walls of the vessel was shown to vary significantly among the polymer materials as well as the color varieties of the same polymer. PLA storage vessels were found to adsorb the least amount of the 98 base pair DNA after 12 hours of storage in 2.5 M NaCl TE buffer whereas the ABS and PC vessels adsorbed up to 97.2 ± 0.2% and 97.5 ± 0.2%. DNA adsorption could be reduced by decreasing the layer height of the 3D printed object, thereby increasing the functionality of the ABS storage vessel. Nylon was found to desorb qPCR inhibiting components into the stored solution which led to erroneous DNA quantification data from qPCR analysis.

Evaluation of Pulmonary Effects of 3-D Printer Emissions From Acrylonitrile Butadiene Styrene Using an Air-Liquid Interface Model of Primary Normal Human-Derived Bronchial Epithelial Cells.

This study investigated the inhalation toxicity of the emissions from 3-D printing with acrylonitrile butadiene styrene (ABS) filament using an air-liquid interface (ALI) in vitro model. Primary normal human-derived bronchial epithelial cells (NHBEs) were exposed to ABS filament emissions in an ALI for 4 hours. The mean and mode diameters of ABS emitted particles in the medium were 175 ± 24 and 153 ± 15 nm, respectively. The average particle deposition per surface area of the epithelium was 2.29 × 107 ± 1.47 × 107 particle/cm2, equivalent to an estimated average particle mass of 0.144 ± 0.042 µg/cm2. Results showed exposure of NHBEs to ABS emissions did not significantly affect epithelium integrity, ciliation, mucus production, nor induce cytotoxicity. At 24 hours after the exposure, significant increases in the pro-inflammatory markers IL-12p70, IL-13, IL-15, IFN-γ, TNF-α, IL-17A, VEGF, MCP-1, and MIP-1α were noted in the basolateral cell culture medium of ABS-exposed cells compared to non-exposed chamber control cells. Results obtained from this study correspond with those from our previous in vivo studies, indicating that the increase in inflammatory mediators occur without associated membrane damage. The combination of the exposure chamber and the ALI-based model is promising for assessing 3-D printer emission-induced toxicity.

Carcinogenic and health risk assessment of respiratory exposure to acrylonitrile, 1,3-butadiene and styrene in the petrochemical industry using the US Environmental Protection Agency method.

Objectives. This study aimed to assess carcinogenic and health risks of respiratory exposure to acrylonitrile, 1,3-butadiene and styrene (ABS) in the petrochemical industry. Methods. This cross-sectional study was conducted in a petrochemical plant producing ABS copolymers. Respiratory exposure to each of acrylonitrile, 1,3-butadiene and styrene was measured using methods No. 1604, No. 1024 and No. 1501 of the National Institute of Occupational Safety and Health (NIOSH), respectively. The US Environmental Protection Agency (USEPA) method was used to assess carcinogenic and health risks. Results. The average occupational exposure to ABS was 560.82 µg m-3 for 1,3-butadiene, 122.8 µg m-3 for acrylonitrile and 1.92 µg m-3 for styrene. The average lifetime cancer risk in the present study was 2.71 × 10-3 for 1,3-butadiene, 2.1 × 10-3 for acrylonitrile and 6.6 × 10-3 for styrene. Also, the mean non-cancer risk (hazard quotient) among all participants for each of 1,3-butadiene, acrylonitrile and styrene was 4.04 ± 6.93, 10.82 ± 14.76 and 0.19 ± 0.11, respectively. Conclusion. The values of carcinogenic and health risks in the majority of the subjects were within the unacceptable risk levels due to exposure to ABS vapors. Hence, corrective actions are required to protect the workers from non-cancer and cancer risks.

Exposure to chemical substances and particles emitted during additive manufacturing.

Additive manufacturing is an innovative technology that allows the production of three-dimensional objects replicating digital models. The aim of this study was to identify whether the use of this technology in a room without mechanical ventilation system may pose a health risk to its users due to the emission of chemical compounds and fine particles. Measurements were conducted in a furnished space with natural ventilation only, during additive manufacturing on a fused deposition modeling printer with 9 different filaments. Both chemicals and particles were sampled. Volatile organic compounds and phthalic acid esters were determined by gas chromatography-mass spectrometry detection. Carbonyl compounds were determined using the high-performance liquid chromatography with diode-array detection method. Fine particle emission studies were carried out using a DiSCmini particle counter (Testo). In the air samples, numerous chemical substances were identified including both the monomers of the individual materials used for printing such as styrene and other degradation products (formaldehyde, toluene, xylenes). Moreover, 3D printing process released particles with modal diameters ranging from 22.1 to 106.7 nm and increased the number concentration of particles in the workplace air. The results of analyses, depending on the type of material applied, showed the presence of particles and chemical substances in the working environment that may pose a risk to human health. Most of the identified substances can be harmful when inhaled and irritating to eyes and skin.

Investigations into the Ability to Reduce Cinnamic Acid as Undesired Precursor of Toxicologically Relevant Styrene in Wort by Different Barley to Wheat Ratios (Grain Bill) during Mashing.

Styrene is a food-borne toxicant in wheat beer and due to its classification as possibly carcinogenic to humans by the International Agency for Research on Cancer in 2002, mitigation strategies had to be developed. Aiming at understanding the impact of the barley to wheat malt ratio (grain bill) during mashing on the contents of soluble and free (i) cinnamic, (ii) p-coumaric, and (iii) ferulic acid, precursors of (i) styrene and the desired vinyl aromatics (ii) 4-vinylphenol and (iii) 2-methoxy-4-vinylphenol in wheat beer, wort was prepared at four different barley to wheat malt ratios of 100:0, 25:75, 50:50, and 0:100 (w/w). Additionally, the malts were produced at different germination temperatures and aeration rates (12/32, 18/35, 18/25, 24/18, and 26/25 (°C; L/min)) to consider these two further parameters as well. Thereby, soluble and free phenolic acid contents in wort showed linear correlations to the percentage of wheat in the grain bill, highlighting the absence of synergistic effects when mixing barley and wheat malts. In contrast, the results described the phenolic acid contents as a function of the concentrations in the respective barley and wheat wort, multiplied by their percentage in the grain bill. However, a clear recommendation for favorable barley to wheat malt ratios leading to a decrease of soluble and free cinnamic acid in wort could not be made, as the contents in the present study proved to be highly dependent on the barley and wheat varieties used during mashing and the parameters applied during malting. This was not the case for p-coumaric acid for which a clear decrease of the soluble and free forms was found with increasing wheat malt contents. Differently, the soluble form of ferulic acid increased with an increasing percentage of wheat malt, while the free form decreased. The malting parameters clearly recommended high germination temperatures and low aeration rates when aiming at a reduction of undesired cinnamic acid in wort. Fortunately, soluble and free p-coumaric and ferulic acid contents were only slightly affected, indicating that the formation of the characteristic wheat beer aroma might not suffer when applying these favorable conditions for styrene reduction.

Associations of Occupational Styrene Exposure With Risk of Encephalopathy and Unspecified Dementia: A Long-Term Follow-up Study of Workers in the Reinforced Plastics Industry.

Exposure to industrial solvents has been associated with encephalopathy. Styrene is a neurotoxic industrial solvent, and we investigated the long-term risk of encephalopathy and unspecified dementia following styrene exposure. We followed 72,465 workers in the reinforced plastics industry in Denmark (1977-2011) and identified incident cases of encephalopathy (n = 228) and unspecified dementia (n = 565) in national registers. Individual styrene exposure levels were modeled from information on occupation, measurements of work place styrene levels, product, process, and years of employment. Adjusted analyses were performed using a discrete survival function. A positive trend for encephalopathy (P < 0.01) and a negative trend for unspecified dementia (P = 0.03) were seen with cumulative styrene exposure accrued during the recent period of up to 15 years. For unspecified dementia and the combination of unspecified dementia and encephalopathy, a positive trend was indicated when applying a 30-year exposure lag (P = 0.13 and P = 0.07). The risk patterns seen following recent exposure probably reflect diagnostic criteria for encephalopathy requiring recent industrial solvent exposure and referral bias rather than association with styrene exposure, while the increasing risk observed for unspecified dementia and the combination of encephalopathy and unspecified dementia following distant exposure indicates an increased risk of dementia following styrene exposure with a long latency period.

Emission fluxes of styrene monomers and other chemicals for products containing expanded polystyrene beads.

Styrene in indoor air can adversely affect human health. In this study, styrene monomer and other chemical emission fluxes for products containing expanded polystyrene beads (pillows, cushions, and soft toys) were measured at various temperatures to simulate typical product use. The contributions of the products to styrene and other chemical concentrations in indoor air and human exposure to these chemicals were estimated, and health risk assessments were performed. The styrene monomer emission fluxes for the samples at 25°C were between 25.3 and 8.73×103 µg/(m2 h). The styrene emission fluxes for the product surfaces increased strongly as the temperature increased, from between 124 and 2.44×104 µg/(m2 h) at 36°C (simulating human body temperature) to between 474 and 4.59×104 µg/(m2 h) at 50°C (simulating inside an automobile in summer). The hexane, heptane, toluene, octane, ethylbenzene, m- and p-xylene, o-xylene, and dodecane emission fluxes at 25°C for the sample that emitted the analytes most readily were high. The maximum estimated styrene and xylene concentrations in indoor air caused by emissions from expanded polystyrene beads at 36°C in a bedroom and automobile were higher than the relevant guidelines. The maximum contribution of a product containing expanded polystyrene beads in a living room, bedroom, or automobile could cause the total volatile organic compound concentration in air to exceed the advisable value (400 µg/m3). The estimated maximum hazard quotients for styrene, toluene, and xylene emitted by a product containing expanded polystyrene beads at 36°C in a bedroom were 0.59, 0.30, and 0.37, respectively. These non-carcinogenic risk values for single products could contribute to the non-carcinogenic risk thresholds being exceeded when multiple products and other sources of chemicals are taken into consideration. The estimated styrene concentrations suggest that products containing expanded polystyrene beads are important sources of styrene to indoor air.

Evaluation of Stoffenmanager and a New Exposure Model for Estimating Occupational Exposure to Styrene in the Fiberglass Reinforced Plastics Lamination Process.

This study aims to evaluate occupational exposure models by comparing model estimations of Stoffenmanager, version 8.2, and exposure scores calculated using a new exposure model with personal exposure measurements for styrene used in the fiberglass-reinforced plastic (FRP) lamination processes in Korea. Using the collected exposure measurements (n = 160) with detailed contextual information about the type of process, working conditions, local exhaust ventilation, respiratory protections, and task descriptions, we developed a new model algorithm to estimate the score for occupational exposures on situation level. We assumed that the source of exposure originates from the near field only (within the breathing zone of workers). The new model is designed as a simple formula of multiplying scores for job classification, exposure potential, engineering controls, chemical hazard, and exposure probability and then dividing the score for workplace size. The final score is log-transformed, ranging from 1 to 14, and the exposure category is divided into four ratings: no exposure (1), low (2), medium (3), and high (4) exposures. Using the contextual information, all the parameters and modifying factors are similarly entered into the two models through direct translation and coding processes with expert judgement, and the exposure estimations and scores using the two models are calculated for each situation. Overall bias and precision for Stoffenmanager are -1.00 ± 2.07 (50th) and -0.32 ± 2.32 (90th) for all situations (n = 36), indicating that Stoffenmanager slightly underestimated styrene exposures. Pearson's correlation coefficients are significantly high for Stoffenmanager (r = 0.87) and the new model (r = 0.88), and the correlation between the two models is significantly high (r = 0.93) (p < 0.01). Therefore, the model estimations using Stoffenmanager and the new model are significantly correlated with the styrene exposures in the FRP lamination process. Further studies are needed to validate and calibrate the models using a larger number of exposure measurements for various substances in the future.

Major AhR-active chemicals in sediments of Lake Sihwa, South Korea: Application of effect-directed analysis combined with full-scan screening analysis.

This study utilized effect-directed analysis (EDA) combined with full-scan screening analysis (FSA) to identify aryl hydrocarbon receptor (AhR)-active compounds in sediments of inland creeks flowing into Lake Sihwa, South Korea. The specific objectives were to (i) investigate the major AhR-active fractions of organic extracts of sediments by using H4IIE-luc in vitro bioassay (4 h and 72 h exposures), (ii) quantify known AhR agonists, such as polycyclic aromatic hydrocarbons (PAHs) and styrene oligomers (SOs), (iii) identify unknown AhR agonists by use of gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOFMS), and (iv) determine contributions of AhR agonists to total potencies measured by use of the bioassay. FSA was conducted on fractions F2.6 and F2.7 (aromatics with log Kow 5-7) in extracts of sediment from Siheung Creek (industrial area). Those fractions exhibited significant AhR-mediated potency as well as relatively great concentrations of PAHs and SOs. FSA detected 461 and 449 compounds in F2.6 and F2.7, respectively. Of these, five tentative candidates of AhR agonist were selected based on NIST library matching, aromatic structures and numbers of rings, and available standards. Benz[b]anthracene, 11H-benzo[a]fluorene, and 4,5-methanochrysene exhibited significant AhR-mediated potency in the H4IIE-luc bioassay, and relative potencies of these compounds were determined. Potency balance analysis demonstrated that these three newly identified AhR agonists explained 1.1% to 67% of total induced AhR-mediated potencies of samples, which were particularly great for industrial sediments. Follow-up studies on sources and ecotoxicological effects of these compounds in coastal environments would be required.

Health risk assessment of occupational exposure to styrene in Neyshabur electronic industries.

Styrene is one of the essential components in making thousands of everyday products. Occupational exposure to styrene causes pulmonary, neurological, genetic and ocular complications, and leukemia and affects reproduction. The aim of this study was to assess the health risks of exposure to styrene in the electronics industry of Neyshabur, Iran. This descriptive and analytical cross-sectional study was carried out in three electronics industries, in Neyshabur city, in 2017-2018. Occupational exposure to styrene was measured according to the NIOSH1501 method, using a low-flow rate sampling pump (0.2 L/min) and an active charcoal absorber tube. Health risk assessment was done according to the Singapore semi-quantitative method and the United States Environmental Protection Agency (OEHHA) method. The average occupational exposure to styrene in men employed in the compact plastic parts production halls was 79.61 mg m-3 (range 28-208.33). 45.8% of exposed subjects (27 people) encountered exposure above the permitted limit. The average lifetime carcinogenic risk of styrene was 1.4 × 10-3; therefore, 100% (59 people) had a definite risk of getting cancer. The highest lifetime risk of getting cancer was observed in plastic injection device users (1.9 × 10-3) and then in shift managers (1.6 × 10-3). The results of this study indicate a definite risk of getting cancer for all workers. Strategies to reduce workers exposure to styrene through engineering controls and routine measurements are necessary.

Occupational exposure to styrene and its relation with urine mandelic acid, in plastic injection workers.

Plastic injection industry workers are exposed to toxic gases and vapors, including styrene. This study aimed to measure exposure to styrene and its relation with urine mandelic acid among plastics injection workers of the electrical parts industry. This descriptive and analytical cross-sectional study was carried out in the plastic injection halls of the electronics industry, in winter 2017 and spring 2018. Styrene gas in the workers' respiratory region was sampled by the NIOSH 1501 method and was analyzed by gas chromatography-mass spectrometry (GC/MAS). Mandelic acid concentration was determined by high-performance liquid chromatography (HPLC). Statistical data analysis was performed with STATA11. The mean of age and working experience in the population under study were 32.4 ± 8.1 and 6.4 ± 5 years, respectively. The average exposure to styrene was 83.2 ± 32.4 mg·m-3 and the mean of urine mandelic acid was 1570.1 ± 720.6 mg·g ceratinine-1. There were 24 workers (45.3%) exposed to levels above permissible limits recommended by national and international organizations. There was a positive and significant correlation between exposure to styrene and urine mandelic acid (P = 0.006, r = 0.4). In multivariate regression, occupational exposure to styrene (P = 0.002, ß = 0.5) was the strongest variable, predicting the amount of urine mandelic acid. Increased occupational exposure to styrene increases mandelic acid in the urine, and applying control measures to reduce exposure to styrene vapor is recommended in high exposure situations.

Determinants of environmental styrene exposure in Gulf coast residents.

BACKGROUND: In a previous study of exposure to oil-related chemicals in Gulf coast residents, we measured blood levels of volatile organic compounds. Levels of styrene were substantially elevated compared to a nationally representative sample. We sought to identify factors contributing to these levels, given the opportunities for styrene exposure in this community. METHODS: We measured blood styrene levels in 667 Gulf coast residents and compared participants' levels of blood styrene to a nationally representative sample. We assessed personal and environmental predictors of blood styrene levels using linear regression and predicted the risk of elevated blood styrene (defined as above the National Health and Nutrition Examination Survey 95th percentile) using modified Poisson regression. We assessed exposure to styrene using questionnaire data on recent exposure opportunities and leveraged existing databases to assign ambient styrene exposure based on geocoded residential location. RESULTS: These Gulf coast residents were 4-6 times as likely as the nationally representative sample to have elevated blood styrene levels. The change in styrene (log ng/mL) was 0.42 (95% CI: 0.34, 0.51) for smoking, 0.34 (0.09, 0.59) for time spent in vehicles and 1.10 (0.31, 1.89) for boats, and -0.41 (-0.73, -0.10) for fall/winter blood draws. Residential proximity to industrial styrene emissions did not predict blood styrene levels. Ambient styrene predicted elevated blood styrene in subgroups. CONCLUSIONS: Personal predictors of increasing blood styrene levels included smoking, vehicle emissions, and housing characteristics. There was a suggestive association between ambient and blood styrene. Our measures of increased regional exposure opportunity do not fully explain the observed elevated blood styrene levels in this population.

Styrene in foods and dietary exposure estimates.

Low levels of styrene may be found in foods as a result of possible migration from polystyrene-based food packaging and as a result of its formation during the biodegradation of a wide variety of naturally occurring compounds with structures similar to styrene. In this study, composite food samples from a recent (2014) Canadian Total Diet Study were analysed for styrene, and levels of styrene in samples of most food types were low in general with a few exceptions (e.g. 4934 ng/g in herbs and spices). Dietary exposures to styrene were estimated for different age-groups based on the occurrence data and the food consumption data for all persons, and they are 0.17-0.38 µg/kg body weight/day for children and 0.12-0.16 µg/kg body weight/day for adults, similar to air intakes (0.085-0.27 µg/kg body weight/day). Thus, for the general population, both food and air contribute similar portions of the total daily intake of styrene for all age groups. However, for the smoking population, intakes from cigarettes are still the major route of exposure to styrene.

Further examination of log Pow-based procedures to estimate biological occupational exposure limits.

OBJECTIVES: To test the reliability of the procedures (described in a previous article) for estimation of biological occupational exposure limits (BOELs). METHODS: Data on four organic solvents (styrene, ethyl benzene, isopropyl alcohol and tetrachloroethylene) were obtained from recent publications and added to previously cited data for 10 organic solvents. Regression analysis was used for statistical evaluation. RESULTS AND DISCUSSION: The previously reported results obtained using 10 solvents were reproduced by the analysis with 14 solvents. Repeated randomized division of the 14 sets into two subgroups of equal size followed by statistical comparisons did not show a significant difference between two regression lines. This reproducibility suggests that the procedures used to estimate BOELs may be applicable across many solvents, and this may be of particular benefit for protecting the health of workers who work with skin-penetrating solvents.

Integrated assessment of persistent toxic substances in sediments from Masan Bay, South Korea: Comparison between 1998 and 2014.

Complexity of anthropogenic influences on coastal ecosystems necessitates use of an integrated assessment strategy for effective interpretation and subsequent management. In this study a multiple lines of evidence (LOE) approach for sediment assessment, that combined use of chemistry, toxicity, and benthic community structure in the sediment quality triad was used to assess spatiotemporal changes and potential risks of persistent toxic substances (PTSs) in sediments of Masan Bay highlighting "long-term changes" between 1998 and 2014. Specific target objectives encompassed sedimentary PTSs (PAHs, alkylphenols (APs), and styrene oligomers), potential aryl hydrocarbon receptor (AhR; H4IIE-luc assay)- and estrogen receptor (ER; MVLN assay)-mediated activities, and finally several ecological quality (EcoQ) indices of benthic community structure. Concentrations of target PTSs in Masan Bay sediments were generally less by half in 2014 compared to those measured in 1998. Second, AhR-mediated potencies in sediments also decreased during this time interval, whereas ER-mediated potencies increased (+3790%), indicating that there has been substantial ongoing, input of ER agonists over the past 16 years. Potency balance analysis revealed that only 3% and 22% of the AhR- and ER-mediated potencies could be explained by identified known chemicals, such as PAHs and APs, respectively. This result indicated that non-targeted AhR and ER agonists had a considerable presence in the sediments over time. Third, EcoQ indices tended to reflect PTSs contamination in the region. Finally, ratio-to-mean values obtained from the aforementioned three LOEs indicated that quality of sediments from the outer region of the bay had recovery more during the period of 16-years than did the inner region. Overall, the results showed that even with the progress supported by recent efforts from the Korean governmental pollution control, PTSs remain a threat to local ecosystem, especially in the inner region of Masan Bay.

Measurements and health impacts of carbon black and BTEXs in photocopy centers.

The purpose of this study was to measure the concentration of carbon black and BTEXs at three photocopy centers and to assess the health risk following exposure. Air samples were collected by sampling in the breathing zone of workers during the class and examination periods. The results found that the concentration of carbon black before operation was higher than morning and afternoon in both class and examination periods. These levels are considerably lower than the suggested limited value set by OSHA. Toluene had the highest concentration but did not exceed of recommended exposure limit by NIOSH. The carbon black and toluene concentrations were higher in examination period than during the normal class period. The results from interview indicate that cough and sneeze are the highest symptom among workers. Carbon black and toluene concentrations in photocopy centers should be concerned in terms of indoor air quality and human health.