• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.428-437
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• 2007

The potential for humic substances to serve as terminal electron acceptors in microbial respiration and the effects of humic substances on microbial azoreduction were investigated. The dissimilatory azoreducing microorganism Shewanella decolorationis S12 was able to conserve energy to support growth from electron transport to humics coupled to the oxidation of various organic substances or $H_2$. Batch experiments suggested that when the concentration of anthraquinone-2-sulfonate (AQS), a humics analog, was lower than 3 mmol/l, azoreduction of strain S12 was accelerated under anaerobic condition. However, there was obvious inhibition to azoreduction when the concentration of the AQS was higher than 5 mmol/l. Another humics analog, anthraquinone-2-sulfonate (AQDS), could still prominently accelerate azoreduction, even when the concentration was up to 12 mmol/l, but the rate of acceleration gradually decreased with the increasing concentration of the AQDS. Toxic experiments revealed that AQS can inhibit growth of strain S12 if the concentration past a critical one, but AQDS had no effect on the metabolism and growth of strain S12 although the concentration was up to 20 mmol/l. These results demonstrated that a low concentration of humic substances not only could serve as the terminal electron acceptors for conserving energy for growth, but also act as redox mediator shuttling electrons for the anaerobic azoreduction by S. decolorationis S12. However, a high concentration of humic substances could inhibit the bacterial azoreduction, resulting on the one hand from the toxic effect on cell metabolism and growth, and on the other hand from competion with azo dyes for electrons as electron acceptor.

• Journal of Ecology and Environment
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• 제35권4호
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• pp.251-258
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• 2012

Many aquatic ecosystems suffer from anthropogenic disturbances, including the introduction of damaging levels of toxic substances. The effects of disturbances include complex relations with various components involved in the systems, and can include physical, chemical, and hydrological disruption depending of the contaminant. Decision Support Systems (DSSs) are developed to help decision makers to deal with complex management crises, through the systematic structuring and evaluation of decisions, and through providing easy-to-use and integrated tools for information elaboration and display. We reviewed various DSSs developed for toxic substances in aquatic ecosystems, and suggested a conceptual framework which is best suited to the management of such issues within Korea. It may assist stakeholders with their decision making process, and in the achievement of a consensus on water management solutions.

• 대한화학회지
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• 제8권2호
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• pp.82-84
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• 1964

It has been pointed out that various substances such as "toxoalbumin", glycoside, choline or readily hydrolysable choline derivatives, alkaloid, lysolecithine etc. are associated with the toxicity of the infected grain. But animal tests and analysis of paper chromatography by author's indicated that a basic substance present in the concentrated extracts from the grain may neither be acetylcholine, betaine, nor choline. This problem still have to be examine further.

• 대한의생명과학회지
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• 제10권3호
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• pp.293-298
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• 2004

This study was performed to compare the growth rates, cellular fatty acid compositions and morphology by using electron microscope of Escherichia coli (E. coli) grown in various conditions including different concentrations of phenol, CdCl₂ and HgCl₂. Ninety eight E. coli strains were isolated from Naktong river and human feces. The content of unsaturated fatty acids, especially 16:1ω7c and 18:1ωc increased as the concentration of phenol and CdCl₂ increased. The content of unsaturated fatty acid increased up to 50 ppb of HgCl₂, but decreased at 75 ppb of HgCl₂. There were more unsaturated fatty acids than saturated fatty acid in the presence of toxic substances. However, the ration was reversed when the affected E. coli was transferred to toxic substance free fresh trypticase soy broth medium. Also, by using transmission electron microscope these cells were observed to various morphological deformation by heavy metals and their deposition on the surface. From these results, we suggested that the changes of major fatty acids composition and morphology of E. coli may be considered to indicate contaminated levels of heavy metals or organic solvents. The information presented here may be useful in predicting effects of heavy-metal and organic solvent contamination in streams and provides a basis for further studies of metal or organic solvent effects on microbial communities.

• 한국환경과학회지
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• 제14권5호
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• pp.513-520
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• 2005

For the destruction of toxic chlorinated organic compounds, this study proposes improved supercritical water oxidation method (multistep oxidation) using sodium nitrate as an oxidizer. This method solves the problems involved in the existing supercritical water oxidation method. Multistep oxidation means that $NaNO_3$ is oxidized to $N_2\;via\;NaNO_2$ and NO. Toxic and hard to destroy organic substances like para-dichlorobenzen(4-DCBz), polychlorinate biphenyl(PCB) ware oxidized to non toxic substances in a condition, in which rapid pressure and temperature rise is restrained as much as possible. 4-dichlorobenzene(4-DCBz) and Polychlorinate biphenyl(PCB) in condition$(450^{\circ}C,\;p_w=0.25g/cm^3,\;30min)$ Was discomposed perfectly.

• 한국위험물학회지
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• 제2권1호
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• pp.12-17
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• 2014

With a rapid growth of domestic industry in korea, now about 25,000 kinds of chemicals are being distributed, and it has been known that just about 15% of them has toxic substances. Recently, South Koreans have an anxiety about the stability and accidents of chemicals because chemical accidents like Gumi hydrofluoric acid accident have occurred. The U.S. has adopted the systems like EPCRA (Emergency Planning and Community Right-to-Know Act), TRI (Toxic Release Inventory) and TSCA (Toxic Substances Control Act), and is also managing the hazardous chemicals by providing the information about them to its people and site workers. Japan's Ministry of Health, Labor and Welfare also has adopted J-CHECK system and is implementing it to let Japanese people know the information of safety of chemicals about REACH. However, the Korean government has a difficult situation to mediate the different idea with the Korean industry to make lower statute of Pre-legislation registration & evaluation of chemicals that will be implemented and Chemical Material Control Association that is being implemented. Especially city and country areas located in the industrial areas need political improvement focusing on vulnerable area through the check about current situation of hazardous chemicals of jurisdiction and management method, but the information about the management situation of small scale work places is insufficient. Therefore this study set up the urgent management area in Ansan Smart Hub through NFPA code according to the types of accident and dander characteristics of each chemical being used in the companies that have less than 50 workers and deal with chemicals located in Ansan Smart Hub in Gyeonggi-do.

• 월간포장계
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• 통권293호
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• pp.48-53
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• 2017

• 대한임상독성학회지
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• 제8권2호
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• pp.61-68
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• 2010

Purpose: Poisoning is a major health problem for the elderly, and poisoning can cause fatal side effects. However, the characteristics and clinical features of elderly patients with acute poisoning have not been well studied in the previous domestic research. So, we tried to analyze the clinical characteristics and toxic substances of the patients who were 65 years old or older and who were admitted to the regional emergency medical center due to acute poisoning. Methods: We retrospectively reviewed the medical records and poisoning protocols of the patients who were 65 years of age or older and who had with acute poisoning and who visited the ED in our emergency center from January 2005 to December 2009. We collected the demographic information, the gender, the underlying diseases, the causes and toxic substances, the initial presentation, the treatment and the outcomes. Results: A total of 2179 poisoned patients visited the hospital during 5 years, and among them 244 were 65 years of age or older (11.2%). The mean age was $75.6{\pm}6.9$ years and the male:female ratio was 1:1.7. The most common cause of poisoning was suicide (73.4%) and the most common source of poisonous substances was their own drugs. Of the substances used for poisoning, benzodiazepine was the most common drug (25.8%), followed by sedatives other than benzodiazepine (25.4%), insecticide (12.7%), chemical agents (12.3%) and herbicides (8.2%). The most common initial presentation was mental change (64.8%). When comparing the factors between the three elderly groups, there was no difference in gender, the cause, the substances and the underlying disease. The outcomes of treatment included ICU admission (56.1%), a good condition at discharge (12.7%) and admission to a general ward (12.7%). The overall mortality rate was 10.2% for the elderly patients. Conclusion: In this Korean study, unlike the foreign studies, the most common cause of poisoning in elderly patients was intentional poisoning. The admission rate was 68.8% and mortality rate was 10.2%.

• 대한화학회지
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• 제8권2호
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• pp.78-81
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• 1964

In this report, some practical problems that are concerned with the infected barley were examined. Most of the toxic substance is present in the bran. It was almost impossible to remove the toxic substance with water or methanol completly, however, we found it is effectively eliminated by soaking the whole grain with 2%, calcium hydroxide suspension for 24 hours. As a detoxifying agent, kieselguhr was very effective; the grain mixed with little amounts (0.4-0.5%) of kieselguhr may be used as an animal feed.

• 한국안전학회지
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• 제32권1호
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• pp.47-52
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• 2017

Chemical accidents occur by a variety of causes and aspects. Accident preparedness substances (APS) are defined by toxic chemicals highly likely to cause accidents due to their high acute toxicity, explosiveness or likely to cause severe damage where a chemical accident occurs among the chemicals. APS is designated and announced by Presidential Decree. However, chemical accidents occurred for recent 7 years were arisen mainly from non-accident preparedness substances, and only 24 species were included as chemical accident trigger among total 69 APS. In addition, APS were designated in 2014 and the list has not been updated since then although it needs to be amended in several aspects. Accordingly, this study analyzes the necessity of modification of APS management, and presents improved plans.