• Proceedings of the Korean Society of Life Science Conference
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• 2004.10a
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• pp.33-34
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• 2004

• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.460-467
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• 2018

Objectives: The objectives of this study are to estimate the inhalation exposure level of benzene for workers using Tier 1 exposure models ECETOC TRA (European Center for Ecotoxicology and Toxicology of Chemicals Target Risk Assessment) and Stoffenmanager, and to investigate their reliability for exposure assessment in K-REACH. Methods: Two exposure scenarios, 'manufacture of benzene' and 'use as solvents,' were developed for assessment of workers' exposure to benzene. The Process Category (PROC) for ECETOC TRA was collected from the European Chemical Agency (ECHA) registration dossier, and the Activity for Stoffenmanager was converted from PROC using translation of exposure models (TREXMO). The information related to exposure, such as working duration, Respiratory Protective Equipment (RPE), Local Exhaust Ventilation (LEV), and Risk Management Measure (RMM) were classified into high, medium, and low exposure conditions. The risk was determined by the ratio of the estimated exposure and occupational exposure limits of benzene. Results: Under high exposure conditions, the worker exposure level calculated from all PROCs and Activities exceeded the risk level, with the exception of PROC 1 and Activity 1. In the medium exposure condition, PROC 8a, 8b, and 9 and Activity 3, 7, and 8 all exceeded the risk, whereas in the low condition, all PROCs and Activities were determined to be safe. As a result, action corresponding with the low exposure condition is required to reduce the risk of exposure among workers in workplaces where benzene is manufactured or used as a solvent. In addition, the predicted exposure levels derived from the exposure models were lower than measured levels. The exposure levels estimated from Stoffenmanager were more conservative than those from ECETOC TRA. Conclusions: This study demonstrates the feasibility of exposure models for exposure assessment through the example of occupational inhalation exposure assessment for benzene. For more active utilization of exposure models in K-REACH, the exact application of collected information and accurate interpretation of obtained results are necessary.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.173-184
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• 2006

From the harmfulness expectation test conducted through a toxicity anticipation program, methylcyclohexane turned out to be harmful and simulative, but no carcinogenicity was anticipated. In a four-hour acute inhalation toxicity test, the result showed that lethal concentration ($LC_{50}$) was 3,750 ppm (15,054 mg/L), which was identified as a harmful substance on the basis of the harmful substance classification standard $2 of the Industrial safety and health law. methylcyclohexane fell under the category $4(2,500 substance from the GHS standard acute toxicity harmfulness classification. Also, from subchronic inhalation toxicity test that included 6 hours a day, five days a week, and for 13 weeks, we could observe weight, activity, long term weight, blood and blood biochemical influence from the exposure of test substance. No-observed effect level (NOEL) was determined below $100{\sim}400ppm$ inboth male and female. This material falls under the Category 2 ($50{\sim}250ppm/6hours/90days$) in the GHS (Globally Harmonized System) standard trace long-term whole body toxicity repeated exposure, and can be classified as a harmful substance in accordance with the Industrial Safety and Health Law harmful substance standard $NOEL{\leq}0.5mg/L/6hr/90day$ (rat).

• Safety and Health at Work
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• v.3 no.3
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• pp.224-234
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• 2012

Objectives: This study was conducted in order to obtain information concerning the health hazards that may result from a 13 week inhalation exposure of n-pentane in Sprague-Dawley rats. Methods: This study was conducted in accordance with the Organization for Economic Co-operation and Development (OECD) guidelines for the testing of chemicals No. 413 'Subchronic inhalation toxicity: 90-day study (as revised in 2009)'. The rats were divided into 4 groups (10 male and 10 female rats in each group), and were exposed to 0, 340, 1,530, and 6,885 ppm n-pentane in each exposure chamber for 6 hour/day, 5 days/week, for 13 weeks. All of the rats were sacrificed at the end of the treatment period. During the test period, clinical signs, mortality, body weights, food consumption, ophthalmoscopy, locomotion activity, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were assessed. Results: During the period of testing, there were no treatment related effects on the clinical findings, body weight, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, relative organ weight, and histopathological findings. Conclusion: The no-observable-adverse-effect level (NOAEL) of n-pentane is evaluated as being more than 6,885 ppm (20.3 mg/L) in both male and female rats. n-pentane was not a classified specific target organ toxicity in the globally harmonized classification system (GHS).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.2
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• pp.73-81
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• 2011

The purpose of this study was to obtain scientific information regarding classification and health hazards that may result from a 13 weeks inhalation exposure of isoprene in Sprague-Dawley (SD) rats. The testing method was conducted in accordance with OECD guidelines for the testing of chemicals No. 413. The Rats were divided into 4 groups (10 male and 10 female rats in each group) and exposed to 0, 360, 1,620, 7,300 ppm isoprene in each exposure chamber for 6 h/day, 5 days/week, for 13 weeks. As a result, there were no mortality or abnormality during the period of study and did not show any significant changes of body weight. There were no dose response changes in urinalysis, hematological and serum biochemical value examination. Relative organ weight was increased significantly the right kidney in 7,300 ppm group of male rats. In female rats, relative organ weight of the left kidney and the both lungs in 1,620 ppm group and the left lung and the both kidneys in 7,300 ppm group were increased significantly. But the histopathological findings did not reveal any exposure-related changes. According to the above results, the no observable adverse effect level (NOAEL) of isoprene was 7,300 ppm (20.3 mg/L) in both male and female rats. In conclusion, Isoprene was not classified specific target organ toxicity of the 'Standard for Classification and Labeling of Chemical Substance and Material Safety Data Sheet' (Ministry of Employment and Labor, 2009).

• Toxicological Research
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• v.33 no.3
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• pp.239-253
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• 2017

Neodymium is a future-oriented material due to its unique properties, and its use is increasing in various industrial fields worldwide. However, the toxicity caused by repeated exposure to this metal has not been studied in detail thus far. The present study was carried out to investigate the potential inhalation toxicity of nano-sized neodymium oxide ($Nd_2O_3$) following a 28-day repeated inhalation exposure in male Sprague-Dawley rats. Male rats were exposed to nano-sized $Nd_2O_3-containing$ aerosols via a nose-only inhalation system at doses of $0mg/m^3$, $0.5mg/m^3$, $2.5mg/m^3$, and $10mg/m^3$ for 6 hr/day, 5 days/week over a 28-day period, followed by a 28-day recovery period. During the experimental period, clinical signs, body weight, hematologic parameters, serum biochemical parameters, necropsy findings, organ weight, and histopathological findings were examined; neodymium distribution in the major organs and blood, bronchoalveolar lavage fluid (BALF), and oxidative stress in lung tissues were analyzed. Most of the neodymium was found to be deposited in lung tissues, showing a dose-dependent relationship. Infiltration of inflammatory cells and pulmonary alveolar proteinosis (PAP) were the main observations of lung histopathology. Infiltration of inflammatory cells was observed in the $2.5mg/m^3$ and higher dose treatment groups. PAP was observed in all treatment groups accompanied by an increase in lung weight, but was observed to a lesser extent in the $0.5mg/m^3$ treatment group. In BALF analysis, total cell counts, including macrophages and neutrophils, lactate dehydrogenase, albumin, interleukin-6, and tumor necrosis factor-alpha, increased significantly in all treatment groups. After a 4-week recovery period, these changes were generally reversed in the $0.5mg/m^3$ group, but were exacerbated in the $10mg/m^3$ group. The lowest-observed-adverse-effect concentration of nano-sized $Nd_2O_3$ was determined to be $0.5mg/m^3$, and the target organ was determined to be the lung, under the present experimental conditions in male rats.

• Journal of the Korean Institute of Gas
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• v.21 no.1
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• pp.6-17
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• 2017

Objectives : The purpose of this study was to obtain information regarding Globally Harmonized System(GHS) classification and health hazards that may result from a 4 weeks inhalation exposure of 3-Methylpentane in Sprague-Dawley rats. Methods : The testing method was conducted in accordance with OECD guidelines for the testing of chemicals No. 412(Subacute Inhalation Toxicity). The Rats were divided into 4 groups(5 male and 5 female rats in each group) and exposed to 0 ppm, 284 ppm, 1,135 ppm, 4,540 ppm 3-Methylpentane in each exposure chamber for 6 h/day, 5 days/week, for 4 weeks. After two weeks, the test animals were autopsied and carried out blood test and biochemical tests and histopathological examination. We used PRISTIMA (Toxicology data management system) to confirm the system and to have confidence of the raw data. Results : No death and particular clinical presentation including weight change and change of feed rate was observed. Relationship between dose, gender and response was also not significantly changed in hematologic examination, biochemical examination of blood and blood coagulation time. The histopathologic lesions caused by the test substance did not appear. Conclusions : NOAEL(No Observable Adverse Effect Level) of 3-Methylpentane is more than 4,540 ppm in male group and female group and the Ministry of Employment and Labor Guidance Announcement No. 2013-37(criteria for the classification marks and Safety of Chemicals) Specific target organ toxicity(repeated exposure) was determined with a substance that is not the separator material.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.05a
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• pp.151-151
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• 2001

According to the epidemiological studies in chromium workers, hexavalent chromium is associated with the risk of lung cancer. Reactive oxygen species produced by hexavalent chromium exposure may play an important role in the carcinogenesis process. We measured one kind of oxidative DNA damages, 8-hydroxydeoxyguanosine (8-OHdG) and its repair activities as an indicators of cellular oxidative stress in rat lungs by the repeated inhalation exposure to sodium chromate.(omitted)

• Environmental Engineering Research
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• v.24 no.4
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• pp.654-661
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• 2019

This study assessed the stabilization of fluorine (F)-contaminated soil using calcium hydroxide (Ca(OH)₂) and the consequent changes in human health risk. The bioavailable F decreased to 3.5%, (i.e., 57.9 ± 1.27 mg/kg in 6% Ca(OH)₂-treated soil sample) from 43.0%, (i.e., 711 ± 23.4 mg/kg in control soil sample). This resulted from the conversion of water-soluble F to stable calcium fluoride, which was confirmed by XRD spectrometry. Soil ingestion, inhalation of fugitive dust from soil, and water ingestion were selected as exposure pathways for human health risk assessment. Non-carcinogenic risks of F in soils reduced to less than 1.0 after stabilization, ranging from 4.2 to 0.34 for child and from 3.0 to 0.25 for adult. Contaminated water ingestion owing to the leaching of F from soil to groundwater was considered as a major exposure pathway. The risks through soil ingestion and inhalation of fugitive dust from soil were insignificant both before and after stabilization, although F concentration exceeded the Korean soil regulatory level before stabilization. Our data suggested that substantial risk to human health owing to various potential exposure pathways could be addressed by managing F present in soil.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.1
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• pp.78-88
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• 2002

Experimental animals were divided into 5 groups; normal, cadmium control, and 3 experimental groups. Cadmium control and experimental groups were exposed to 1 mg/㎥ of cadmium aerosol in air by inhalation exposure for 6 hours/day, 5 days/week during 4 weeks. Dosages of 20, 40, and 80mg/kg of extracts of persimmon leaves were intraperitoneally injected to experimental groups respectively and several toxicological parameters and induction of metallothionein were measured from the rats that inhaled cadmium aerosol in air. The results of this study were as follows. Cadmium concentration that cadmium control and experimental groups were inhaled was 0.980±0.061 mg/㎥. Mass median diameter of cadmium aerosol for inhalation exposure was 4.93±0.483㎛. Cadmium content of normal group in lung was 0.088㎍/g and the highest cadmium content in lung, 55.492㎍/g was from 80mg/kg dose group. Cadmium concentration of normal group in blood was 0.348㎍/100㎖ and the highest cadmium concentration in blood, 2.642㎍/100㎖ was from cadmium control. Cadmium concentration of normal group in liver was 0.010㎍/g and the highest cadmium concentration in liver, 31.100㎍/g was from 20mg/kg dose group. Cadmium concentration of normal group in kidney was 0.030㎍/g and the highest cadmium concentration in kidney, 2.526㎍/g was from cadmium control. Cadmium concentration of normal group in intestine was O.064㎍/g and the highest cadmium concentration in intestine, 0.300㎍/g was from 80mg/kg dose group. The highest cadmium concentration in urine by week was 6.080㎍/day from 20mg/kg dose group in the fouth week and the highest cadmium concentration in feces by week was 341.731㎍/day from 20mg/kg dose group in the fouth week. Metallothionein concentration of normal group in lung was 5.769㎍/g and the highest in lung, 30.986㎍/g was from 80mg/kg dose group. Metallothionein concentration of normal group in liver was 38.856㎍/g and the highest in liver, 169.378㎍/g was from 40mg/kg dose group. Metallothionein concentration of normal group in kidney was 22.228㎍/g and the highest in kidney, 47.898㎍/g was from 80mg/kg dose group. Metallothionein concentration of normal group in intestine was 2.170㎍/g and the highest in intestine, 13.642㎍/g was from 80mg dose group.