• Journal of Environmental Science International
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• v.12 no.11
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• pp.1173-1179
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• 2003

Laboratory sorption isotherm batch studies have been attempted to elucidate interaction of synthetic pyrethroids (bifenthrin and permethrin) with sediments and their fractions. As a nonlinear isothermal model, the Freundlich equation was applied to sorption results obtained from sediments to investigate the relationship between synthetic pyrethroids and sediments containing different amounts of organic carbon. Results demonstrated that the sorption capabilities of bifenthrin and cis- and trans-permethrin was in the order of bifenthrin, cis-permethrin and trans-permethrin, respectively, indicating that adsorbed bifenthrin was the most stable followed by cis- and trans-permethrin in all sediments. Their sorption capability was closely related to organic carbon contents in sediments. Higher sorption was observed in sediments containing higher organic carbon contents. Sorption study extended into the fractions, clay and humic acids, extracted from a sediment, indicated that higher sorption capacity in humic acids occurred than in the clay of both examined bifenthrin and permethrin. This study demonstrates the sorption of synthetic pyrethroids with sediments, and will help in the understanding of the transport and fate of synthetic pyrethroids existing in field sediments.

• Environmental Analysis Health and Toxicology
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• v.25 no.1
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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.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.38-47
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• 1995

The Bioconcentration factor (BCF) is used as an important criterion in the risk assessment of environmental contaminants. Also it can be used as indicator of biomagnification of environmentally hazardous chemicals through food-chain as well as a tool for ranking the bioconcentration potential of the chemicals in the environment. This paper reports the measured BCF value on Chlorothalonil in Carassius auratus(goldfish), under steady state, and examined correlation between the BCF value and the partition coefficient or acute toxicity or physicochemical properties. Carassius auratus(goldfish) was chosen as test organism and test period were 3-day, 5-day. Experimental concentrations were 0.005, 0.01 and 0.05 ppm. Chlorothalonil in fish tissue and in test water were extracted with n-hexane and acetonitrile. GC-ECD was used to detecting and quantitating of Chlorothalonil. Partition coefficient was determined by stir-flask method. $LC_{50}$ was determined on Chlorothalonil. Carbaryl and BPMC. The obtained results were as follows. 1. It was possible to determine short term BCFs of Chlorothalonil through relatively simple procedure in environmental concentrations. 2. $BF_3$ of Chlorothalonil in concentration of 0.005, 0.01 and 0.05 ppm were 2.1866$\pm$0.23446, 3.5269$\pm$0.23517, 10.2045$\pm$0.18053 and BCFs were 6.6543$\pm$0.55257, 6.9774$\pm$0.02500, 23.4576$\pm$2.06884, respectively. 3. Chlorothalonil concentration in fish extract and BCFs of Chlorothalonil were increased as increasing test concentration and prolonging test period. 4. Fate of test-water concentration on Chlorothalonil was greater than that of control-water con-centration. It is considered that greater fate of test-water concentration on Chlorothalonil is due to hydrolyzing nitrile group under the mild condition and substituting chloro group by some aromatic compounds in test water. 5. Determined logP of Chlorothalonil was 2.80. And determined $LC_{50}$ of Chlorothalonil in time of 24, 48, 72 and 96 hr were 0.1684, 0.1402, 0.1400, 0.1352(mg/l) respectively. And $LC_{50}$ of Carbaryl in above times were 19.918, 18.635, 18.466, 18.12(mg/l) respectively. $LC_{50}$ of BPMC were 10.248, 9.166, 9.087, 8.921(mg/l) respectively. 6. It is suggested that the BCF of Carbamates depend on partition coefficients. But BCF of Chlorothalonil, organochlorine pesticide, would be strongly influenced by steric, electronic effect of substituents than partition coefficient.

• Economic and Environmental Geology
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• v.36 no.3
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• pp.171-176
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• 2003

The fate and behavior of polycyclic aromatic hydrocarbons(PAHs) and heavy metals in the environment are mainly controlled by their interactions with various components of soils and sediments. Due to their large surface area and abundance in many soils, smectites may greatly influence the fate and transport of the contaminants. In our experiment, PAH sorption by hexadecyltimethylammonium(HDTMA)-modified smectite linearly increased in proportion to the amount of HDTMA added on the clay. However, trimethylammonium(TMA)-modified smectite did not show superiority in its sorption of PAH compared with the HDTMA-smectite or dodecyltrimethylammonium(DTMA)- smectite. Meanwhile, the smectites modified with the same cationic surfactants adsorbed Cd$^{2＋}$(heavy metal) significantly from water at low surfactant loading level, but the Cd$^{2＋}$ adsorption linearly decreased as the loading of surfactant increased. The result shows that the sorption tendency of organoclays for organic or inorganic contaminants was significantly influenced by the amount and size of the surfactants added on the clay. This reveals that the stabilization and configuration of cationic surfactant formed on the clay interlayer of different sizes may be an important factor in controlling the sorptive capacity of each pollutant in the environment.

• KSBB Journal
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• v.20 no.6
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• pp.408-412
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• 2005

In a previous research, it has been found that it could be possible to increase the partial pressure of hydrogen and hydrogen yield by scavenging the $CO_2$ from the heads pace of reactor. In this research, the positive and negative effects of the $CO_2$ scavenging especially on the fate of by-products were investigated by a batch experiment. Production and conversion of by-products had critical relationships with hydrogen evolution and consumption. The maximum hydrogen fraction in the headspace was increased from 66.4 to 91.2% by removing the $CO_2$ in the headspace and the degradation rate of glucose was also enhanced. The removal of $CO_2$ effectively hindered the homoacetogenesis but caused several negative phenomena. The degradation of ethanol, one of the main products, was inhibited by the high partial pressure of hydrogen and/or the absence of $CO_2$. Also it was observed that other by-products such as propionate, propanol, acetone, etc. could not be degraded further after produced from glucose. On the other hand, solventogenesis was not observed in spite of the high hydrogen partial pressure apart from previous researches and it might hinder the excess production of acetate, which could cause overall inhibition. From this research, it could be implicated that the $CO_2$ scavenging method could be recommended if the fermentation was purposed to produce hydrogen and ethanol.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.5
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• pp.481-494
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• 2005

The monitoring of persistent organic pollutants (POPs) in the atmosphere is a basis for the study of the fate of POPs in multimedia environments. Recently, passive air samplers (PASs) for POPs have been developed. In this paper, we deal with the principle, properties, and applications of the PAS. The principle of PAS, which has no pump, is physical sorption of semi-volatile organic chemicals on various sorbent materials. The PAS is much smaller than a high-volume air sampler and does not need electricity. These properties of the PAS make it possible to conduct various-scaled environmental monitoring all over the world including the Arctic and Antarctic, but the major disadvantage of PAS is its long sampling periods up to 2 years. To date, four kinds of PAS have been developed: polyurethane foam (PUF), polymer-coated glass (POG), semi-permeable membrane devices (SPMDs), and XAD resin-based PAS. Among them, SPMDs have been commercialized and are most widely used now. Meanwhile, the POPs emitted from China have a large potential to influence the levels and fates of POPs in Korea. Since characteristics of PAS are quite useful to monitor long-range transport of POPs, the use of PAS is highly recommended.

• Journal of the Korean Chemical Society
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• v.45 no.1
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• pp.40-44
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• 2001

Benomyl, one of the known endocrine disrupting chemicals, was analyzed to understand the its fate in water. Benomyl analysis process in water sample include the following sequential steps. Hydrolysis of benomyl into carbendazim, solvent extraction, concentration, and the concentration of final carbendazim solution was determined by LC/MS (TOF). Recoveries of the spiked samples were good with the range of 80.6 to 118.6% and the MDL was 1,600 times lower than that of LC/UVD method. The use of LC/MS (TOF) successfully eliminated the positive error incurred by interferencing materials in the matrix.

• Journal of Environmental Policy
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• v.1 no.1
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• pp.75-90
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• 2002

Methyl tertiary-butyl ether(MTBE) is used as an octane enhancer in gasoline. MTBE can enter the environment at any stage in the production, storage, and transport of undiluted MTBE or MTBE-blended gasoline. Although data on concentrations of MTBE in the environment are not available, modelling of fate of MTBE has provided predictions for concentrations of MTBE in the various media to which humans and other organisms may be exposed. Many individuals do not taste or smell MTBE at the $5{\mu}g/L$ level, and thus may be exposed to higher concentrations for a significant amount of time. MTBE exposure through inhalation is likely to be below health-threatening levels, except for occupational workers such as gasoline station attendants and auto mechanics. It should be stressed, however, that there are important data gaps in our understanding of the acute and chronic toxicity of MTBE. Little or no research concern including being conducted that directly addresses these issues. Rather than any immediate ban on MTBE, I recommend consideration of phasing out MTBE in USA and other countries. During the transition phase, a number of policies are suggested to reduce the risk of using MTBE. One of these policies is that the state should invest in a research program. Such research should, for example, examine effective alternatives for motor vehicle fuels, and detect concentrations of MTBE in ambient air, water, and other environmental media.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.107-113
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• 2018

Maintaining adequate residual chlorine concentration is an important criteria to provide secure drinking water. The chlorine decay can be influenced by unstable flow due to the transient event caused by operation of hydraulic devices in the pipeline system. In order to understand the relationship between the transient event and the chlorine decay, the probability density function based on the water demand curve of a hypothetical water distribution system was used. The irregular transient events and the same number of events with regular interval were assumed and the fate of chlorine decay was compared. The chlorine decay was modeled using a generic chlorine decay model with optimized parameters to minimize the root mean square error between the experimental chlorine concentration and the simulated chlorine concentration using genetic algorithm. As a result, the chlorine decay can be determined through the number of transients regardless of the occurrence intervals.

• Journal of Life Science
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• v.9 no.2
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• pp.19-23
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• 1999

Bisphenol-A and related conpounds recently have been reported to be estrogenic since it has been demonstrared in laboratory stuides that they mimic the effects of estrogen. Bisphenol-A refered to as "environmental estrogen" are suspected of causing health effect in living body through disruption of endocdrine system. In this review, the occurrence, environmental fate, and biological effects of bisphenol-A are presented. To provide understanding to the potential for endocrine disruption due to environmental estrogen, the physiology of bisphenol-A mammalian and fish is also reviewed. For empty can, the migrationof bisphenol-A form food conducted epoxy coating was effected by the test conditions and it increased in order to water and 4% acetic acid. Extracts from foods packed in lacquer coated can also showed estrogenic activity. Bisphenol-A was found as a contaminant not only in the liquid food cans, but also in water autoclave in can. The used of coating certain food-packaging material may require closer scrutiny to determine when bisphenol-A contribute to advert exposure of consumers to estrogenic xenobiotics. Human breast cancer MCF cell added bisphenol-A cultivated to study the ability of bisphenol-A to elicit of bisphenol-A estrogenic bioresponse in this system. Bisphenol-A, similar to estradiol, induced PR activation in transiently transfected anterior and posterior pituitary cells.