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Sung J.H.,Korea Conformity Laboratories | Ji J.H.,Samsung | Park J.D.,Chung - Ang University | Song M.Y.,Korea Conformity Laboratories | And 12 more authors.
Particle and Fibre Toxicology | Year: 2011

Background: Gold nanoparticles are widely used in consumer products, including cosmetics, food packaging, beverages, toothpaste, automobiles, and lubricants. With this increase in consumer products containing gold nanoparticles, the potential for worker exposure to gold nanoparticles will also increase. Only a few studies have produced data on the in vivo toxicology of gold nanoparticles, meaning that the absorption, distribution, metabolism, and excretion (ADME) of gold nanoparticles remain unclear.Results: The toxicity of gold nanoparticles was studied in Sprague Dawley rats by inhalation. Seven-week-old rats, weighing approximately 200 g (males) and 145 g (females), were divided into 4 groups (10 rats in each group): fresh-air control, low-dose (2.36 × 104particle/cm3, 0.04 μg/m3), middle-dose (2.36 × 105particle/cm3, 0.38 μg/m3), and high-dose (1.85 × 106particle/cm3, 20.02 μg/m3). The animals were exposed to gold nanoparticles (average diameter 4-5 nm) for 6 hours/day, 5 days/week, for 90-days in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and lung function were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and organ weights were measured. Cellular differential counts and cytotoxicity measurements, such as albumin, lactate dehydrogenase (LDH), and total protein were also monitored in a cellular bronchoalveolar lavage (BAL) fluid. Among lung function test measurements, tidal volume and minute volume showed a tendency to decrease comparing control and dose groups during the 90-days of exposure. Although no statistically significant differences were found in cellular differential counts, histopathologic examination showed minimal alveoli, an inflammatory infiltrate with a mixed cell type, and increased macrophages in the high-dose rats. Tissue distribution of gold nanoparticles showed a dose-dependent accumulation of gold in only lungs and kidneys with a gender-related difference in gold nanoparticles content in kidneys.Conclusions: Lungs were the only organ in which there were dose-related changes in both male and female rats. Changes observed in lung histopathology and function in high-dose animals indicate that the highest concentration (20 μg/m3) is a LOAEL and the middle concentration (0.38 μg/m3) is a NOAEL for this study. © 2011 Sung et al; licensee BioMed Central Ltd. Source


Robbins C.A.,Veritox Inc. | Krause M.W.,Veritox Inc. | Atallah R.H.,Veritox Inc. | Atallah R.H.,Dade Moeller and Associates Inc | Plisko M.J.,Environmental Profiles Inc.
Journal of Chemical Health and Safety | Year: 2012

It has been reported that the presence of ≤0.1% benzene in base solvents often used for cleaning is likely to result in exposure concentrations above the current OSHA PEL. This prediction was based upon calculations that depend largely on the concentration of benzene assumed to be present in a solvent mixture. Measurements of exposure during work simulations and more comprehensive modeling studies show that many factors other than the benzene content of the bulk solvent influence personal and area vapor concentrations. This study examines benzene exposure due to trace amounts of benzene in solvents available recently, and whether exposure in excess of the OSHA benzene standard occurs when 10 and 50. mL of base solvents containing up to 0.1% benzene are used during a manual cleaning process in a poorly ventilated room.Breathing zone (BZ) concentrations were measured for benzene, toluene and xylene during repetitions of a cleaning procedure using a small cloth to wipe a metal paint tray with 10 and 50. mL of consumer-grade toluene and xylene alone and toluene spiked with 0.1% benzene. Air samples were collected in the breathing zone (BZ) for 15. min to determine the short-term exposure. Separate 2. hr samples were collected in the BZ and general area to obtain time-weighted average (TWA) exposure concentrations. All samples were analyzed with a GC-FID utilizing NIOSH Method 1501.A near field-far field (NF-FF) model was used in conjunction with Monte Carlo simulation to predict airborne benzene, toluene, and xylene concentrations and to quantify uncertainty in the input parameters of the model. Variables including solvent evaporation time and air movement around the worker during the work activity were analyzed over a range of possible values. The result after 10 5 iterations of Monte Carlo simulation was a range of possible outcomes and the likelihood that each would occur; these outcomes are compared to the measured airborne concentrations.Cleaning the metal pan with 10-50. mL of toluene or xylene with or without 0.1% benzene did not result in benzene exposures in excess of either the OSHA PEL 8-hr TWA (1.0. ppm) or action level (0.5. ppm). The ratio of predicted or modeled to measured benzene concentration ranged from 0.42 to 2.1. The ratio of predicted or modeled to measured xylene and toluene concentration ranged from 0.92 to 3.7. Application of the NF-FF model under the conditions studied indicates a reasonable degree of reliability in forecasting airborne solvent concentrations under the conditions studied. © 2012 Division of Chemical Health and Safety of the American Chemical Society. Source


Song K.S.,Korea Conformity Laboratory | Sung J.H.,Korea Conformity Laboratory | Ji J.H.,Samung Electronics Ltd | Lee J.H.,Hoseo University | And 9 more authors.
Nanotoxicology | Year: 2013

In a previous study, the lung function, as indicated by the tidal volume, minute volume, and peak inspiration flow, decreased during 90 days of exposure to silver nanoparticles and was accompanied by inflammatory lesions in the lung morphology. Therefore, this study investigated the recovery from such lung function changes in rats following the cessation of 12 weeks of nanoparticle exposure. Male and female rats were exposed to silver nanoparticles (14-15 nm diameter) at concentrations of 0.66 × 106 particles/cm 3 (49 μg/m3, low dose), 1.41 × 106 particles/cm3 (117 μg/m3, middle dose), and 3.24 × 106 particles/cm3 (381 μg/m3, high dose) for 6 h/day in an inhalation chamber for 12 weeks. The rats were then allowed to recover. The lung function was measured every week during the exposure period and after the cessation of exposure, plus animals were sacrificed after the 12-week exposure period, and 4 weeks and 12 weeks after the exposure cessation. An exposure-related lung function decrease was measured in the male rats after the 12-week exposure period and 12 weeks after the exposure cessation. In contrast, the female rats did not show a consistent lung function decrease either during the exposure period or following the exposure cessation. The histopathology showed a gradual recovery from the lung inflammation in the female rats, whereas the male rats in the high-dose group exhibited persistent inflammation throughout the 12-week recovery period. Therefore, the present results suggest a potential persistence of lung function changes and inflammation induced by silver nanoparticle exposure above the no observed adverse effect level. © 2013 Informa UK, Ltd. Source


Kim Y.S.,Korea Environment and Merchandise Testing Institute | Kim Y.S.,Seoul National University | Song M.Y.,Korea Environment and Merchandise Testing Institute | Park J.D.,Chung - Ang University | And 10 more authors.
Particle and Fibre Toxicology | Year: 2010

Background: The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, consumer, medicinal, pesticide, and home products; however, silver nanoparticles remain a controversial area of research with respect to their toxicity in biological and ecological systems.Results: This study tested the oral toxicity of silver nanoparticles (56 nm) over a period of 13 weeks (90 days) in F344 rats following Organization for Economic Cooperation and Development (OECD) test guideline 408 and Good Laboratory Practices (GLP). Five-week-old rats, weighing about 99 g for the males and 92 g for the females, were divided into four 4 groups (10 rats in each group): vehicle control, low-dose (30 mg/kg), middle-dose (125 mg/kg), and high-dose (500 mg/kg). After 90 days of exposure, clinical chemistry, hematology, histopathology, and silver distribution were studied. There was a significant decrease (P < 0.05) in the body weight of male rats after 4 weeks of exposure, although there were no significant changes in food or water consumption during the study period. Significant dose-dependent changes were found in alkaline phosphatase and cholesterol for the male and female rats, indicating that exposure to more than 125 mg/kg of silver nanoparticles may result in slight liver damage. Histopathologic examination revealed a higher incidence of bile-duct hyperplasia, with or without necrosis, fibrosis, and/or pigmentation, in treated animals. There was also a dose-dependent accumulation of silver in all tissues examined. A gender-related difference in the accumulation of silver was noted in the kidneys, with a twofold increase in female kidneys compared to male kidneys.Conclusions: The target organ for the silver nanoparticles was found to be the liver in both the male and female rats. A NOAEL (no observable adverse effect level) of 30 mg/kg and LOAEL (lowest observable adverse effect level) of 125 mg/kg are suggested from the present study. © 2010 Kim et al; licensee BioMed Central Ltd. Source

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