Showing papers by "Pilje Kim published in 2014"

Combined repeated-dose toxicity study of silver nanoparticles with the reproduction/developmental toxicity screening test

Abstract: Combined repeated-dose toxicity study of citrate-capped silver nanoparticles (7.9 ± 0.95 nm) with reproduction/developmental toxicity was investigated in rats orally treated with 62.5, 125 and 250 mg/kg, once a day for 42 days for males and up to 52 days for females. The test was performed based on the Organization for Economic Cooperation and Development test guideline 422 and Good Laboratory Practice principles. No death was observed in any of the groups. Alopecia, salivation and yellow discolouration of the lung were observed in a few rats but the symptoms were not dose-dependent. Haematology, serum biochemical investigation and histopathological analysis revealed no statistically significant differences between control group and the treated groups. Toxicity endpoints of reproduction/developmental screening test including mating, fertility, implantation, delivery and foetus were measured. There was no evidence of toxicity.

Uptake and bioaccumulation of titanium- and silver-nanoparticles in aquatic ecosystems

Abstract: Metal-based nanoparticles (NPs) such as silver (Ag) and titanium dioxide (TiO2) are widely used in industrial and household applications. Because of the increasing use of such manufactured NPs and their release into the natural environment, NPs are likely to have a widespread geographic distribution. Concerns over discharge of considerable amounts of these NPs into the environment are increasing. Although recent studies have raised concerns about the health risks and environmental impacts of NPs, little is known about their environmental fate and behavior, particularly in aquatic ecosystems, which is the final destination of NPs due to precipitation and runoff. In this review, we discuss possible routes of environmental exposure as well as the occurrence, behavior, and bioaccumulation of Ag-NPs and TiO2-NPs in the environment.

Didecyldimethylammonium chloride induces oxidative stress and inhibits cell growth in lung epithelial cells

Abstract: Didecyldimethylammonium chloride (DDAC) is a commonly used biocide that can cause lung inflammation and fibrosis. However, the mechanism of this pulmonary toxicity is unclear. Thus, we examined the mechanism for the DDAC-induced pulmonary toxicity at the cellular level by using lung epithelial cells. DDAC induced cell damage, including injury of mitochondria and lysosomes with the release of lactate dehydrogenase (LDH), as well as caused cell morphological changes and necrotic reactions. In a clonogenic assay, treatment with a low concentration of DDAC (5 μM) for 10 days reduced both the number and size of the colonies, which are indexes of cell growth. In addition, DDAC increased intracellular reactive oxygen species (ROS) production while it decreased glutathione (GSH) activity. Therefore, our results suggest that exposure to even a low concentration of DDAC may inhibit cell growth and cause oxidative stress in lung epithelial cells.

Effects of ionization on the toxicity of silver nanoparticles to Japanese medaka (Oryzias latipes) embryos

Abstract: Increase in the use of manufactured nanomaterials (NMs) has led to concerns about the environmental impacts. Especially, hazard of metal-based NMs is more severe due to ions released from surface by water quality parameters and physicochemical properties after entering into the water environment. However, little is known about the effects of ionization on the toxicity of metal-based NMs in the water environment. To address this question, we prepared the suspensions of silver nanoparticles (AgNP) at 25 μg L−1 containing different concentrations of Ag+ (5, 10, 20, 45, and 75% Ag+ to total Ag), and evaluated their toxicity to Japanese medaka (Oryzias latipes) embryos. Higher Ag+ ratios in the AgNP suspension, suggesting the lower number of particles, led to the higher adverse effects on embryos and sac-fries. In addition, histopathology analysis revealed that AgNPs penetrated through chorion of eggs and skin membrane, and were distributed into the tissues. The results imply that the ionization could decrease...

Combined effects of the cyanobacterial toxin microcystin‐LR and environmental factors on life‐history traits of indigenous cladoceran Moina macrocopa

Abstract: Environmental factors are important in that they might interact with toxicants and could affect the concentration–response relationship of the toxicants in the water environment. Microcystins (MCs) produced by algal blooming are natural toxins that exert severe impacts on aquatic organisms. Despite the possibility of interaction effects between environmental factors and MCs, very few studies have been carried out to date. In the present study, the authors evaluated the effect of 3 environmental factors on chronic toxicity of MC-leucine-arginine (MC-LR; 0 µg/L, 0.8 µg/L, 4 µg/L, 20 µg/L, 100 µg/L, 500 µg/L) to the freshwater invertebrate Moina macrocopa. Three environmental factors were determined to reflect the reasonable worst conditions of the water body in South Korea: high water temperature (25 °C), the highest concentration of nutrients (ammonia-nitrogen [NH3-N] = 3.8 mg/L; nitrate-nitrogen [NO3-N] = 8.5 mg/L) during the occurrence of algal bloom, and 2 pH conditions of 7.0 and 9.0, which satisfy the test acceptance criteria for the Daphnia test. Among the various environmental factors being tested, high water temperature and NO3-N elevated chronic toxicity of MC-LR, whereas NH3-N reduced toxicity. Water pH did not influence chronic toxicity of MC-LR to M. macrocopa. This observation suggests that those environmental factors are responsible for changing the trend of MC-LR toxicity. Environ Toxicol Chem 2014;33:2560–2565. © 2014 SETAC

Environmental Toxicology COMBINED EFFECTS OF THE CYANOBACTERIAL TOXIN MICROCYSTIN-LR AND ENVIRONMENTAL FACTORS ON LIFE-HISTORY TRAITS OF INDIGENOUS CLADOCERAN MOINA MACROCOPA

Abstract: Environmental factors are important in that they might interact with toxicants and could affect the concentration-response relationship ofthetoxicants in thewater environment. Microcystins(MCs)produced byalgalblooming arenatural toxinsthat exertsevere impactsonaquaticorganisms.Despite thepossibilityofinteractioneffects betweenenvironmentalfactorsand MCs,veryfewstudieshave beencarriedouttodate.Inthepresentstudy,theauthorsevaluatedtheeffectof3environmentalfactorsonchronictoxicityofMC-leucine-

Human Risk Assessment of Perchloroethylene Considering Multi-media Exposure

Abstract: National Institute of Environmental Research, Incheon, KoreaABSTRACTObjectives: Perchloroethylene (PCE) is a volatile chemical widely used as a solvent in the dry-cleaning andtextile processing industries It was evaluated as Group 2 “probably carcinogenic to humans” by the IntegratedRisk Information System (IRIS) of the United State Environmental Protection Agency (US EPA) in 2012 Inorder to provide a scientific basis for establishing risk management measures for chemicals on the nationalpriority substances list, aggregate risk assessment was conducted for PCE, included in the top-10 substancesMethods: We conducted the investigation and monitoring of PCE exposure (eg, exposure scenario, detectionlevels, and exposure factors, etc) and assessed its multi-media (eg, outdoor air, indoor air, and ground water)exposure risk with a deterministic and probabilistic approach Results: In human risk assessment (HRA), the level of human exposure was higher in the younger age groupThe exposure level through inhalation at home was the highest among the exposure routes Outdoor air or uptakeof drinking water represented less than 1% of total contributions to PCE exposure These findings suggested thatthe level of risk was negligible since the Hazard Index (HI) induced by HRA was below one among all agegroups, with a maximum HI value of 017 when reasonable maximum exposure was applied Conclusion: In conclusion, it was suggested that despite low exposure risk, further studies are neededconsidering main sources, including occupational exposure Keywords: Monte-carlo method, Perchloroethylene, Risk assessment