• Environmental Analysis Health and Toxicology
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• v.24 no.3
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• pp.181-191
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• 2009

As an effort to prevent serious accidents involving oxygen deficiency and suffocation in confined spaces and to identify the causes of such accidents, the present study investigated relevant accidents and systems in Korea and other countries. This study also conducted a number of experiments at lethal concentration levels of oxygen deficiency using SD rats and observed the changes of experimental animals with humidity, organic gas (toluene), hydrogen sulfide, carbon monoxide and so on at the oxygen deficient environment. The results of the study are as follows. 1. The results from the experiment conducted using SD rats at lethal concentration levels of oxygen showed that there were no casualties at the 7% oxygen concentration level, but the mortality increase to 20% at 6% oxygen, it was jumped to 90% at 5% oxygen, and it was also dramatically reached 100% at 4% oxygen concentration. Therefore, 5.5% was calculated as the $LC_{50}$ (rat, 4hr) from these dose-response experiments with oxygen deficiency. 2. When we changed the level of toluene, $H_2S$, CO, humidity, and so on, in an oxygen deficient environment, it was observed that the small concentrations of $H_2S$ and CO make the highest effect on animals. In case of 350 ppm $H_2S$, it resulted in 30% mortality, and the 100% mortality was shown in 1,200 ppm CO concentration. The mortality increased as an oxygen deficient condition. However in the case of toluene up to 1,000 ppm, it were not affected with oxygen deficiency, and it did not indicate any significant differences in mortality as 20%, 90% humidities.

• Fire Science and Engineering
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• v.16 no.2
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• pp.75-80
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• 2002

In this paper, some experiments of a heat release rate and toxicity for underground utility 22.9kv cable in fire was conducted and analysed applying plume equation and smoke chamber test separately, A 22.9 ㎸ power cable is selected for testing heat release in ISO 9705 geometry and toxicity production is measured with NES 713 (British-Naval Engineering Standard)test. In test results, Cable heat release reached about 60 ㎾ above 1.2 m from heptane pan and CO generated lethal concentration under 30 min. exposure condition.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.18-25
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• 2013

It may occur health hazards or death by suffocation or acute poisoning in case of oxygen deficiency in ambient or exposure to harmful gas. As a part of accident prevention, we studied the change of activity and lethal dose by changing the concentration of several hazardous gas with inhalation exposure chamber and laboratory animals. We investigated the lethality and motility change during either the 4 hrs whole body exposure to oxygen, nitrogen, toluene, $H_2S$, CO and 48 recovery. As results, it is estimated that 5% oxygen concentration as lethal concentration and 5.5% as $LC_{50}$ (rat, 4 hrs) with statistics for dose-response. The results of lethality in oxygen deficient condition (approximately 6%), the lethalities were 40%, 20% with 20 ppm $H_2S$, 600 ppm CO respectively, and was not increased the lethality with 8% CO. Thus, it was confirmed that the $H_2S$, CO had influence to lethal dose, while toluene had low fluence.

• Fire Science and Engineering
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• v.30 no.2
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• pp.7-18
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• 2016

This study evaluated the toxicity of the burning gas from the synthetic wood products used in housings or warehouses. The combustion products of five materials, viz. impregnated laminated board, MDF, Douglas fir plywood, core plywood, and Lauan retardant, were analyzed using SEM, FTIR and a Cone Calorimeter. For the Lauan retardant, 256,965 ppm of carbon dioxide ($CO_2$) and 1,475 ppm of sulfur dioxide ($SO_2$) were measured, which are 2.5 times and 3.6 times as high as their lethal concentrations of 100,000 ppm and 400 ppm, respectively. For the impregnated laminated board, 1,569 ppm of nitrogen dioxide ($NO_2$) was measured, which is 6 times as high as its lethal concentration of 250 ppm. For MDF, 795 ppm of ammonia ($NH_3$) was measured, which is higher than its lethal concentration of 750 ppm. As a result, most internal-finishes generated toxic combustion products at levels higher than their lethal concentrations, which underlines the importance of the selection and manufacturing of internal-finish materials.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.639-654
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• 2016

This study building materials by relates to human hazard assessment in accordance with the combustion gas SEM, the flame-retardant foam FTIR and cone calorimeter to configure the Forest products of MDF and preservative treated Lauan two kinds of Retardant styrofoam, Styrofoam, Urethane foam and gypsum board four kinds of plastics material by the combustion gas were each analyzed. MDF was burned to the structure of the wood and the glue evenly mixed combustion area preservative treated Lauan, kept constant even in the form of high heat to penetrate deep into the wood flame retardant agents. Retardant styrofoam is due to feed my Dropped dissolved inorganic flame retardant without the fire-stick and confirmed that the weak form of gypsum board, but keep the column. In MDF ammonia ($NH_3$), lethal concentration (750 ppm) compared to 795 ppm, preservative treated Lauan is carbon dioxide ($CO_2$) that was greater than 2.5 times the lethal concentration (100,000 ppm) to 256,965 ppm, the lethal concentration (500 ppm) of hydrogen chloride (HCl). The Urethane greater than 697 ppm, 434 ppm also greatly exceeding the nitrogen dioxide ($NO_2$) lethal concentration (250 ppm) in Retardant styrofoam and 398 ppm was released. It is confirmed that the human body is extremely harmful gas emitted from most of the materials to be utilized as basic data for evaluating the hazard-specific human future building material.

• Korean journal of applied entomology
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• v.62 no.4
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• pp.267-275
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• 2023

Botanical extracts are employed in management of aphids. Extracts from Tanacetum cineariaiaefolium, Derris elliptica, and Sophora flavescens are widely used to control various insects. In this study, we determined concentrations of insecticidal active ingredients in commercial botanical extracts of these plants, and we investigated the time and concentration for lethal results with the green peach aphid, Myzus persicae. The concentrations of active ingredients, pyrethrins from T. cineariaiaefolium, rotenone from D. elliptica, and matrine and oxymatrine from S. flavescens, were determined after their fractionation by liquid chromatography followed by mass analysis and comparison with standard compounds. The extracts were tested for lethality in a bioassay with green peach aphids. Sprays at defined doses were applied to tobacco leaves infested with aphid nymphs. The lethal concentrations (LC50) were 20.4 ppm for pyrethrins, 34.1 ppm for rotenone, and 29.6 ppm for matrine at 48 h after treatments. At 100 ppm application levels, the lethal time LT50 was 13.4 h for pyrethrin, 15.1 h for rotenone, and 14.4 h for matrine. Kaplan-Meier analysis indicated the lethal times for the three botanical extracts at 100 ppm were significantly faster than application of a chemical insecticide, Sulfoxaflor, applied at the recommended level. These results provide baselines to develop and formulate single or mixed preparations containing botanical extracts to control green peach aphids on commercial crops.

• The Korean Journal of Malacology
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• v.20 no.1
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• pp.93-105
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• 2004

Arkshell clams, Scapharca broughtonii, are economically important edible bivalves and widely cultivated in the Southern coast of Korea. Recently, the production of S. broughtonii has been dramatically decreased and various reasons including chemical pollution were suspected to be related to the production declines. However, it remains unknown whether the chemical pollution levels of the surrounding environments were high enough for the biological and ecological disturbance for the population of S. broughtonii, because no systematic toxicological study using S. broughtonii has been conducted previously. In the present study, we exposed arkshell clams, S. broughtonii to various waterborne pollutants including heavy metals (Cd, Cu and Hg), ammonia and organotins (tributyltin and triphenyltin) to determine the effect concentrations of these pollutants for the survival of S. broughtonii for 20 days. The median lethal concentrations ($LC_50$) of S. broughtonii were 2.1 mg/l for Cd, 0.065 mg/l for Cu, 0.40 mg/l for Hg, 79.4 mg/l for total ammonia (1.9 mg/l for unionized ammonia), 0.5 ${\mu}$g/l for TBT, and 14${\mu}$g/l for TPhT. Lethal toxicity of the most pollutants increased with both exposure duration and concentration. The toxicity of TBT was greatest for S. broughtonii, followed by TPhT > Cu > Hg > Cd > ammonia. The sensitivities of S. broughtonii to heavy metals and TBT were comparable to those of other aquatic organisms, but they were relatively tolerable to ammonia. The environmental concentrations of the tested pollutants were compared with the effect concentrations of those for the survival of S. broughtonii to assess the potential risks of the pollutants in the field conditions.

• Ocean Science Journal
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• v.40 no.2
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• pp.61-66
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• 2005

Benthic amphipod, Grandidierella japonica widely inhabits the Korean coastal waters and is developed as a standard test species for sediment toxicity tests. We exposed G. japonica to various pollutants including 4 kinds of inorganic metals (Ag, Cd, Cu and Hg), tributyltin [TBT], ammonia and 7 polycyclic aromatic hydrocarbon (PAH) compounds (acenaphthene, chrysene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene) to estimate the no observed effect concentration (NOEC) and the median lethal concentration (LC50) of each pollutant during the 96-hour acute exposure. Among all tested pollutants, TBT was most toxic to G. japonica, and Rg was most toxic among inorganic metals. The toxicity of pyrene to G. japonica was greatest among PAH compounds, followed by fluoranthene, phenanathrene, acenaphthene, fluorene and naphthalene. The toxicity of PAH compounds was closely related to their physico-chemical characteristics such as $K_ow$ and water solubility. G. japonica responded adequately to pollutant concentrations and exposure durations, and the sensitivity of G. japonica to various inorganic and organic pollutants was generally comparable to other amphipods used as standard test species in ecotoxicological studies, indicating this species can be applied in the assessment of environments polluted by various harmful substances.

• Applied Biological Chemistry
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• v.34 no.1
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• pp.67-74
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• 1991

In order to improve the productivity of ethanol by sugar-alcohol-tolerant Saccharomyces cerevisiae D1, the effect of addition of $Ca^{2+}$ on the alcohol fermentation was investigated. The addition of $Ca^{2+}$led to both the improvement of ethanol productivity and the increase of viable cell concentration. The optimal concentration of $Ca^{2+}$ was 0.8 mM. The higher was initial concentration of glucose, the greater effect of $Ca^{2+}$ was observed. Ethanol inhibition of growth, specific death rate in lethal concentration of ethanol, and extracellular final pH decreased by the addition of $Ca^{2+}$. The effect of $Ca^{2+}$ supplementation was explained by the increase of its ethanol tolerance.

• Journal of the Korean Society of Safety
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• v.30 no.4
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• pp.51-55
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• 2015

There are various studies on the fire suppression process but the study on second pollution from fire products is not enough yet. Therefor, in this study verify that environmentally-friendly properties($LC_{50}$) of foam extinguishing agent with increases its amount used through with Fish-Acute Toxicity Test using a fish named Misgurnus anguillicaudatus that is appointed by OECD Test Guideline. In conclusion, proven that environmentally friendly properties of the agent of hoseo university through 16 times of LC50 than that of market.