• Environmental Analysis Health and Toxicology
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• 제25권1호
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• pp.41-55
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• 2010

The aims of this study were to develop the suitable "system software" in chemical ranking and scoring (CRS) for the food hazardous chemicals associated with environmental emission and to suggest the priority lists of food contamination by environmental-origined pollutants. Study materials were selected with reference to the priority pollutants list for environment and food management from domestic and foreign research and the number of study materials is 103 pollutants (18 heavy metals, 10 PBTs, 10 EDs, and 65 organic compounds). The Food-CRS-Korea system consisted of the environmental fate model via multimedia, transfer environment to food model, and health risk assessment by contaminated food intake. We have established that health risks of excess cancer risks, hazard quotients (HQs) by chronic toxicity and HQs by reproductive toxicity convert to score, respectively. The creditable scoring system was designed to consider uncertainty of quantitative risk assessment based on VOI (Value-Of-Information). The predictability of the Food-CRS-Korea model was evaluated by comparing the presumable values and the measured ones of the environmental media and foodstuffs. The priority lists based on emissions with background-level-correction are 15 pollutants such as arsenic, cadmium, and etc. The priority lists based on environmental monitoring date are 17 pollutants including DEHP, TCDD, and so on. Consequently, we suggested the priority lists of 13 pollutants by considering the several emission and exposure scenarios. According to the Food-CRS-Korea system, arsenics, cadmium, chromes, DEHP, leads, and nickels have high health risk rates and reliable grades.

• 한국농공학회지
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• 제40권2호
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• pp.102-111
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• 1998

Large amount of sludge have been generating in the process of water and wastewater treatment in urban area, and it has been making many environmental problems. Currently almost of sludge is landfilled, and since sludge is difficult to handle and dehydrate, the permeated water from the filled-in ground contaminate the surrounding soil and groundwater which may cause serious environmental and sociological problems. The organic component in sludge can be almost removed through the heat treatment process, and the final product is called artificial soil or artificial media according to the temperature control. To produce artificial media using sludge, chabazite and lime were used as an additive, and the mixture of sludge & additives was thermally treated in the firing kiln at about 800~1, 100。C for about fifteen minutes. The physical and chemical characteristics of the produced artificial media were analyzed, and it showed that it can be used as an artificial media for plant production or soil conditioner for farmland. The concentrations of the toxic heavy metals in the artificial media were lower than the soil quality standard for farmland. The characteristics of produced artificial media, using the mixture of sludge and additives through the heat treatment, is similar to the natural chabazite and soil. The analyzed result of the mineral composition of artificial media showed that it has a characteristics similar to natural stable soil, so the produced artificial media may be applied to farmland or water culture without causing adverse effect. Therefore this study showed that the above process can be a feasible alternative for sludge treatment.

• Environmental Analysis Health and Toxicology
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• 제19권2호
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• pp.191-200
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• 2004

Zinc (Zn) is an essential element in biological process, however inadequate Zn status in general population have been recognized. To update the knowledge for Zn-cadmium (Cd) interaction, we studied the intestinal uptake and transport, and the expression of metal transporter proteins (divalent metal transporter 1, DMT1 ; metal transporter protein 1, MTP1 ; zinc transporter 1, ZnTl ; metallothionein 1 , MT1) in duodenum after Cd exposure using Zn deficient animal model. Rats were led Zn deficient (ZnD, 0.5-1.0 mgZn/kg) or Zn supplemented (ZnS, 50mg Zn/kg) diet for 4 weeks, and followed single administration of $^{109}$ CdCl$_2$orally. The body Zn flatus and tissue Cd concentration were determined at 24 hrs after Cd administration. Total body burden of Cd and Cd absorption index (AI, %) were estimated based on the tissue Cd analyzed. DMT1, MTP1, ZnTl and MT1 mRNA were analyzed by using RT-PCR method. Feeding of Zn deficient diet for 4 weeks produced a reduced body weight gain and a depletion of body Zn. Tissue Cd concentration, body burden of Cd and Cd absorption index were higher in the ZnD diet fed rats than the ZnS diet red rats. Especially, Cd concentration in the small intestine (duodenum, jejunum and ileum) and the colon of FeD diet fed rats were higher markedly than in the FeS diet group. The expression levels of DMT1, MTP1 and ZnT1 mRNA in FeD diet fed rats were similar to the FeS diet. The level of MT1 mRNA expression was significantly lower in the FeD than the FeS diet fed rats. Taken together, theses results indicate that Zn deficiency in diet induce an increased intestinal absorption and tissue retention of Cd, and down -regulate the MT1 expression in the intestine which might be play a part of role in Cd absorption and transport in mammalian. These findings suggest that deficiency of essential metal could be enhanced the toxicity of toxic, non-esstial metals through the metal-metal interaction.

• Environmental Engineering Research
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• 제16권4호
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• pp.187-203
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• 2011

Chlorophenols (CPs) are widely used industrial chemicals that have been identified as being toxic to both humans and the environment. Zero valent iron (ZVI) and iron based bimetallic systems have the potential to efficiently dechlorinate CPs. This paper reviews the research conducted in this area over the past decade, with emphasis on the processes and mechanisms for the removal of CPs, as well as the characterization and role of the iron oxides formed on the ZVI surface. The removal of dissolved CPs in iron-water systems occurs via dechlorination, sorption and co-precipitation. Although ZVI has been commonly used for the dechlorination of CPs, its long term reactivity is limited due to surface passivation over time. However, iron based bimetallic systems are an effective alternative for overcoming this limitation. Bimetallic systems prepared by physically mixing ZVI and the catalyst or through reductive deposition of a catalyst onto ZVI have been shown to display superior performance over unmodified ZVI. Nonetheless, the efficiency and rate of hydrodechlorination of CPs by bimetals depend on the type of metal combinations used, properties of the metals and characteristics of the target CP. The presence and formation of various iron oxides can affect the reactivities of ZVI and bimetals. Oxides, such as green rust and magnetite, facilitate the dechlorination of CPs by ZVI and bimetals, while oxide films, such as hematite, maghemite, lepidocrocite and goethite, passivate the iron surface and hinder the dechlorination reaction. Key environmental parameters, such as solution pH, presence of dissolved oxygen and dissolved co-contaminants, exert significant impacts on the rate and extent of CP dechlorination by ZVI and bimetals.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3755-3761
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• 2013

This study aims to assess the ecological risk of the hazardous air pollutants (HAPs) emitted in the semiconductor manufacturing processes in Korea by using Quantitative Structure Activity Relationship (QSAR, EPA, US, EPI $Suite^{TM}$ 4.1). Owing to the absence of environmental standards of hazardous air pollutants in the semiconductor manufacturing processes in Korea, 18 HAPs in the semiconductor field included in both the US EPA NESHAPs and the hazardous air pollutant list of Ministry of Environment in Korea were selected. As a results 8 chemicals (44.4%) of the selected 18 HAPs were VOCs. Cyanides (cyanides) and ethylene oxides (epoxy resins), and tetrachloro-ethylene (aliphatic compounds, halides) showed long half-lives. Cyanide HAPs especially had the highest half-life with the estimated value of 356.533 days. Nickel compounds (heavy metal compounds) possessed the highest water solubility followed by acetaldehyde (aldehyde compounds), ethylene oxides, and 1,4-dioxanes. The halides, including tetrachloro-ethylenes, carbon tetra-chlorides, benzene (aromatic compounds), and lead (heavy metals), are estimated to take the longest time for biodegradation. Tetrachloroethylene, with the acute toxicity end point of 3.685-7.033 mg/L, was assessed to be the most highly toxic substance among the 18 HAPs. However, considering the absence of the HAPs in the common category of log $K_{ow}{\geq}4$and $BCF{\geq}500$, which indicates the standard of bioconcentration potentials, potentials of the bioconcentration are considered to be low.

• 한국초전도ㆍ저온공학회논문지
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• 제22권2호
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• pp.7-11
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• 2020

When rivers and lakes are contaminated with numerous contaminants, usually the contaminants are finally deposited on the sediments of the waterbody. Many clean up technologies have been developed for the contaminated sediments. Among several technologies dredging is one of the best methods because dredging removes all the contaminated sediments from the water and the contaminated sediments can be completely treated with physical and chemical methods. However the most worried phenomenon is suspension of fine particles during the dredging process. The suspended particle can release contaminants into water and resulted in spread of the contaminants and the increase of risk due to the resuspension of the precipitated contaminants such as heavy metals and toxic organic compounds. Therefore the success of the dredging process depends on the prevention of resuspension of fine particles. Advanced dredging processes employ pumping the sediment with water onto a ship and release the turbid water pumped with sediment into waterbody after collection of sediment solids. Before release of the turbid water into lake or river, just a few minutes allowed to precipitate the suspended particle due to the limited area on a dredging ship. However the fine particle cannot be removed by the gravitational settling over a few minutes. Environmental technology such as coagulation and precipitation could be applied for the settling of fine particles. However, the process needs coagulants and big settling tanks. For the quick settling of the fine particles suspended during dredging process magnetic separation has been tested in current study. Magnetic force increased the settling velocity and the increased settling process can reduce the volume of settling tank usually located in a ship for dredging. The magnetic assisted settling also decreased the heavy metal release through the turbid water by precipitating highly contaminated particles with magnetic force.

• 한국축산시설환경학회지
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• 제2권2호
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• pp.147-154
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• 1996

In an attempt to recycle as feed or fertilizer, broiler litter containing rice hull was manually composted under the control of peak temperature of piles(uncontrolled or controlled below $70^{\circ}C$ or below $60^{\circ}C$) in each of three $1.0\;{\times}\;1.0\;{\times}\;1.2m$ dimensional facilities. Changes of nutritional and microbiological parameters were evaluated throughout the 8 weeks of processing period. The initial content of crude protein(29.6%) decreased to 17.8% after 8 weeks of composting. The rapid nitrogen(N) loss observed in the early phase was attributed mainly to non-protein-N(NPN) loss. The initial content of ash(19.1%) increased to $26{\sim}29%$ after 8 weeks. For toxic heavy metals, Cr, Pb, and Hg contents of final composts were far less than the maximum tolerance levels allowed in food or compost. Bacterial growth was rather depressed until the second week, increased thereafter, and reached to peak($10^{12}cfu$ level) at the 4th week of composting. With composting, actinomycetes were active at the level of $10^7\;to\;10^9$. Fungi were active during the first to third week of composting. In general, control of pile temperature below $70^{\circ}C$ did not remarkably alter the nutritional and microbiological parameters of broiler litter compost, compared to that of pile temperature below $60^{\circ}C$. Further researches on prevention from the rapid loss of NPN in the early phase of composting are required for more effective recycling of broiler litter.

• 한국환경보건학회지
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• 제18권2호
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• pp.82-91
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• 1992

The examination of the pollutants originated from domestic sewage, industrial and agricutural activities the existences of some toxic heavy metals, organic matters and pathogenic microorganisms. A recent report of WHO brought out that such pollutants are in existence with above roughly 2,000 kinds of chemical substances and amongst them about 750 chemicals have been indentified by drinking water. And above 600 kinds of them are organic pollutants and in addition these include carcinogenic mutagenic and poisonous substances. This is not intended to embody a study of broad confined to various approaches on organic materials, and therefore will be THM produced on injection of chlorine at water filtration plant. To specify the relations between THM and factors having an effect upon THM such as TOC, Cl$_{2}$, Temperature, pH and reaction time, first of all the recovery ratio for analytical methods of THM (Head sapce, purge and trap, Liquid/ Liquid Extraction methods) was investigated. Provided that by using it,the correction coefficients are obtained, the accuracy of data might be able to be enhanced through analysis.The result of the experiments are given in the followings. 1) Among three kinds of analytical methods, recovery rate was higher in order of purge and trap Liquid/Liquid Extraction, Head space. There is no great difference in recovery rate among three methods. 2) The higher the concentration of TOC, the more the amount of THM. 3) The higher the reaction temperature, the more the amount of THM. 4) The longer the reaction time, the more the amount of THM. 5) The higher the pH, the more the amount of THM. 6) The higher the concectration of chlorine, the more the amount of THM.

• Advances in environmental research
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• 제6권3호
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• pp.173-187
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• 2017

Heavy metals, such as vanadium, are some of the most toxic types of water contaminants. In this study, vanadium was removed using a new composite adsorbent called BAZLSC. The impacts of pH and initial concentration of vanadium(V) on the elimination effectiveness of this metal by using BAZLSC were investigated in the first step of the study. Vanadium removal increased as pH increased to 3-3.5, and initial concentration increased to 60-70 mg/L. The removal efficiency then decreased. Central composite design and response surface methodology were employed to examine experimental data. Initial concentration of V ($mg.L^{-1}$), pH, and dosage of adsorbent (g/L) were the independent factors. Based on RSM, the removal effectiveness of vanadium was 86.36% at the optimum of initial concentration (52.69 mg/L), pH (3.49), and adsorbent dosage (1.71 g/L). Also adsorption isotherm investigations displayed that the Freundlich isotherm could explain vanadium adsorption by BAZLSC better than the Langmuir isotherm. Beside them, desorption studies showed sorption was slightly diminished after six continuous cycles.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 경북지부 결성 및 추계학술발표회 논문집
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• pp.39-49
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• 1996

Hundreds of contaminated sites have been generated due to the past mismagement of toxic substances, the lack of adequate environmental controls and ignorance of the potential environmental impacts of general activities in Canada. The general public, industry and governments have been addressing the contaminated sites with a number of cleanup responses. Environmental protection and remediation have become top priorities for the public and private sectors alike in Canada. Between the late 1980s and the early 1990s, the Canadian Environmental Protection Act and Canada's Green Plan were followed by provincial and territorial laws and policies to regulate contaminated sites. The National Contaminated Site Remediation Program(NCSRP) was initiated in 1989. It has been administered through bilateral agreements between the federal and participating provincial/territorial governments. They have committed a total of $250 million toward orphan site cleanup and technology development/demonstration over a five year period. The federal government has committed an additional $25 million to assess contaminated sites on federal crown land. Over 40 orphan high-risk contaminated sites, over 230 federal sites and over 35 technology development/demonstration projects have been addressed. The Canadian Council of Ministers of the Environment has developed a series of guidance documents to ensure a consistent and successful implementation of the Program. The management/regulation scheme of contaminated sites generally consists of： 1) identifying and investigating sites, 2) determining site contamination, 3) recognizing responsibility and liability, 4) assessing priority for remediation, 5) activation, evaluation and implementing remediation options, and 6) documenting remediation completion. The NCSRP supported the successful development/demonstration of a wide range of innovative remedial technologies. They are related to stabilization/solidification, thermal washing/flushing, advanced oxidation, sonics, and groundwater contaminated with hydrocarbons, PAHS, PCBs, heavy metals, and other hazardous pollutants in a variety of site environments.