• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.6
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• pp.583-592
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• 2020

This study assessed source depletion in the vadose zones of contaminated sites. The possible range of infiltration rate in Korea was statistically analyzed. The results showed a trend of decreasing leachate concentration of 13 pollutants used for risk assessment. Among them, benzene, ethylbenzene, toluene, and xylene showed a lower leachate concentration in groundwater over time due to their low distribution coefficient and also possible biodegradation effects. The average values of the relative concentration could be taken as a default index due to a very small range of uncertainties. In the case of heavy metals, it was shown that the leachate concentration in a pollutant does not decrease over time. Considering the annually different infiltration, a site-specific source-depletion scenario was applied to Cheongju in North Chungcheong Province. The result was expressed as a time series of the relative concentration of the leachate concentration, and this was compared to the trend by averaged Korean infiltration. Finally, an open-source code that used Python was used to help calculate the leachate concentration by this site-specific infiltration scenario.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.36-42
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• 2024

Background: The use of scented candles and incense sticks, both of which are household products that are burned for indoor deodorization and calming effects, is increasing. Fine dust has been designated as a group 1 carcinogen by the International Agency for Research on Cancer. Volatile organic compounds (VOCs) affect air pollution and can cause diseases. Objectives: This study aims to determine the effect on indoor air quality by measuring PM_2.5 and VOCs generated when burning scented candles and incense sticks. Methods: Scented candles and incense sticks were selected as household products to burn. As for the target sample, top-selling products (five types of scented candles, five types of incense sticks) were purchased online. The PM_2.5 concentration according to time was measured immediately next to the sample and three meters away from each other in an enclosed space using a real-time aerosol photometer. VOCs were collected as samples under the same conditions using Tenax tubes and were quantitatively analyzed by TD-GC/MS. Results: In the case of scented candles, the concentration of PM_2.5 did not increase during combustion and after being extinguished by placing a cover on the candle. For the incense sticks, the concentration of PM_2.5 averaged 1,901.27 ㎍/m³. After burning scented candles and incense sticks, some VOCs concentrations were increased such as ethyl acetate and BTEX (benzene, toluene, ethylbenzene, xylene). Conclusions: Therefore, when using scented candles, extinguishment by placing a cover on the candle can be expected to reduce PM_2.5. It is advisable to avoid using incense sticks because PM_2.5 concentration increases from the start of combustion.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.67-76
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• 2024

Objectives: Direct reading instruments (DRIs) are widely used by industrial hygienists and other experts for preliminary survey and identifying source locations in many industrial fields. Photoionization detectors (PIDs), which are a form of hand-held portable DRIs, have been used for a variety of airborne vaporized chemicals, especially evaporated hydrocarbon solvents. The benefits of PIDs are high sensitivity between each chemical, competitive price, and portability. With the goal of increasing the accuracy of logged PID concentrations, previous studies have performed tests for the assessment of single chemical compounds, not mixtures. The purpose of this preliminary study was to measure mixtures with a PID and charcoal tube at the same time and compare the accuracy between them. Methods: A chamber test was implemented with different mixtures of hydrocarbon chemicals (acetone, isopropyl alcohol, toluene, m-xylene) and levels in the range of 14 to 864 ppm. Three PIDs and charcoal tubes were connected to the chamber and measured the chemical mixtures simultaneously. A comparison of accuracy and the PID group of concentrations with manufacture correction factor (M_CF) and field correction factor (F_CF) applied was performed. Results: The accuracy of the PID concentrations data-logged from the PID did not meet the accuracy criteria except for the mixture level B and C logged from PID No. 2, which was 18% of all tests for meeting accuracy criteria. The mean and standard deviation (SD) of concentration (ppm) of the charcoal tube followed by each mixtures' level were 10.37±0.26, 155.33±5.28, 300.80±11.65, and 774.93±22.65, respectively. When applying F_CF into the PID concentrations, the accuracy increased by nearly 82%. However, in the case of M_CF, none met the accuracy criterion. Between the PID there were differences of logged concentrations. Conclusions: In this preliminary study, the concentration of a logged PID with F_CF applied was a better way to increase accuracy compared to applying M_CF. We suggest that additional research is necessary to consider environmental factors such as temperature and humidity.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.144-152
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• 1993

A bacterium which degrades efficiently synthetic detergents was isolated from the polluted waters, activated sludge of wastewater treatment plants or polluted soil. This bacterium showed considerably higher growth rate in the agar plate containing $2,000{\mu}g/ml$ of synthetic detergents than any other isolated strains, was identified as a Pseudomonas fluorescens or strains similar to it. The strain was named as a Pseudomonas fluorescens S1. Optimum pH and temperature for the growth of the Pseudomonas fluorescens S1 were pH 7.0 and $30^{\circ}C$, respectively. The strain was resistant to streptomycin and gentamycin, but sensitive to kanamycin. The strain was greatly resistant to zinc chloride, lead nitrate and copper sulfate, but unable to grow in the presence of relatively low concentrations of mercury chloride and silver nitrate. This strain utilized benzene, catechol, cyclohexane and xylene as a sole carbon source. The strain was well grown in the medium containing ABS 10,000${\mu}g$/ml. Degradation of ABS was 55% and 60% at 20${\mu}g$/ml and 100${\mu}g$/ml of ABS, respectively. Benzene ring was degraded 45% in 100${\mu}g$/ml of ABS. During the incubation of the strain in the medium containing ABS 100${\mu}g$/ml and COD 10,000${\mu}g$/ml for 4 days, degradation of ABS and COD were reduced to 40${\mu}g$/ml and 3,200${\mu}g$/ml, respectively. Total amino acid content of the Pseudomonas fluorescens S1 grown with 1,000${\mu}g$/ml of ABS was 115mg/g cell, whereas its content was decreased in the bacterium grown without synthetic detergent by 9.4%.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.100-108
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• 1989

Thirty-six aromatic compound biodegraders; 10 strains for benzoate, 10 for salicylate, 6 for m-toluate, and 10 for DL-camphor were isolated and taxonomically characterized. A mutant Pseudomonas strain, Ben 6-2, derived from Ben 6 revealed remarkably improved ability to metabolize benzoate. Thus enhancement of the average substrate removal rate from 5.2 to 11.0mg/$\ell$/ hr was attained by the mutant. Both of strains Sal 7 and Tol 2, degraders of salicylate and m-toluate respectively, were classified as Pseudomonas sup. Both strains were found to be extremely effective in metabolizing each aromatic substrates. The average substrate degradation rates in minimal salt media containing 2,200mg/$\ell$ of the substrate were calculated to be 40.1 mg/$\ell$/ hr for strain Sal 7 and 33.0mg/$\ell$/ hr for Tol 2. Cam 10, a camphor degrading strain was demonstrated to be capable of mineralizing benzoate, phenol, toluene, octane, cyclohexane and xylene as well as camphor. Strain 1040 isolated from Cam 10 after repented adaptation to 1,000 mg/$\ell$ m-toluate gained the ability to utilize toluate as a sole carbon source. The mutant Brew actively at the expense of a mixture of car-bon sources; camphor, m-toluate, benzoate and phenol (each: 200 mg/$\ell$) and utilized the substances in the preferential order of camphor, phenol, benzoate, and m-toluate. Among the biodegraders examined Cam 1040 and Tol 2 were detected to harbor plasmid. The plasmid from Cam 1001 was determined to be about 98kb, and evidenced to encode the enzyme(s) for the degradation of camphor. For the further diversification of the metabolic potentials of Cam 1040, the NAH 2 plasmid of Pseudomonas putida NCIB 9816 was transferred to Cam 1040 by conjugation. The exconjugant obtained, Cam 1043, proved to gain an additional ability to metabolize salicylate and naphthalene.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.605-617
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• 2015

The ultimate goal of this research is to develop a botanical biofiltration system that combines a green interior, biofiltering, and automatic irrigation to purify indoor air pollutants according to indoor space and the size of biofilter. This study was performed to compare the stability of air flow characteristics and removal efficiency (RE) of fine dust within a wall-typed (vertical) botanical biofilter depending on humidifying cycle and to investigate RE of volatile organic compounds (VOCs) by the biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be suitable for indoor space utilization. As a result, relative humidity, air temperature, and soil moisture content (SMC) within the biofilter showed stable values regardless of three different humidifying cycles operated by the metering pump. In particular, SMCs were consistently maintained in the range of 27.1-29.7% during all humidifying cycles; moreover, a humidifying cycle of operating for 15 min and pausing for 45 min showed the best horizontal linear regression (y = 0.0008x + 29.09) on SMC ($29.0{\pm}0.2%$) during 120 hour. REs for number of fine dust (PM10) and ultra-fine dust (PM2.5) particles passed through the biofilter were in the range of 82.7-89.7% and 65.4-73.0%, respectively. RE for weight of PM10 passed through the biofilter was in the range of 58.1-78.9%, depending on humidifying cycle. REs of xylene, ethyl benzene, total VOCs (TVOCs), and toluene passed through the biofilter were in the range of 71.3-75.5%, while REs of benzene and formaldehyde (HCHO) passed through the biofilter were 39.7% and 44.9%, respectively. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was very effective for indoor air purification.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.11
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• pp.1001-1010
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• 2010

The purpose of this study is to investigate the concentration levels of particle materials ($PM_{10}$, asbestos), gas materials ($CO_2$, CO, $NO_2$, HCHO, Rn, VOCs) and total suspended colony (TSC), and the correlations among these materials in indoor air quality of 54 multiple-use facilities and 15 public-use facilities of Gwangju. The highest mean concentration of $PM_{10}$ was $69.2\;{\mu}g/m^3$ at indoor parking place, followed by childcare facilities, large commercial building and subway station building. The highest mean concentration of CO was 2.7 ppm at indoor parking place and that of $CO_2$ was 604.1 ppm at medical service facilities. The highest mean concentration of $NO_2$ was 0.036 ppm at indoor parking place. The geomean concentration of HCHO was $3.6\;{\mu}g/m^3$ in all facilities and the highest was $631.8\;{\mu}g/m^3$ at art gallery. The geomean concentration of VOCs (5 species) was $24.14\;{\mu}g/m^3$ in all facilities and toluene was the highest material of $15.30\;{\mu}g/m^3$, followed by xylene, ethylbenzene, benzene and styrene. The highest mean concentration of TSC was $625.3\;CFU/m^3$ at jjimjilbang, followed by childcare facilities, medical service facilities and large commercial building. The highest of asbestos was 0.0072 each/cc at childcare facilities and that of radon was 1.41 pCi/L at art gallery. PM10 showed positive correlations to TSC with $R^2\0.5332$ by lognormal equation at childcare facilities. CO2 showed positive correlations to CO at childcare facilities and indoor parking place. Lognormal equation fitted to the VOCs data more than normal equation in all facilities.

• Journal of Life Science
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• v.30 no.2
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• pp.156-161
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• 2020

Since industrialization, the production and utilization of various chemicals has contributed to improving the quality of our lives, but the subsequent discharge of massive waste is inevitable, and environmental pollution is becoming more serious every day. Exposure to chemicals as a result of environmental pollution is having a negative effect on human health and the ecosystem, and cleaning up the polluted environment that can affect our lives is a very important issue. Toxic aromatic compounds have been detected frequently in soil, groundwater, and wastewater because of the extensive use of oil products, and phenol, which is used to produce synthetic resins, textiles, and dyes, is one of the major pollutants, along with insecticides and preservatives. Phenol can cause dyspnea, headache, vomiting, mutation, and carcinogenesis. Phenol-degrading bacterium DWB-1-8 was isolated from the activated sludge of textile wastewater; this strain was identified as Comamonas testosteroni by 16S rRNA gene sequencing. The optimal culture conditions for the cell growth and degradation of phenol were 0.7% K₂HPO₄, 0.6% NaH₂PO₄, 0.1% NH₄NO₃, 0.015% MgSO₄·7H₂O, 0.001% FeSO₄·7H₂O, an initial pH of 7, and a temperature of 30℃. The strain was also able to grow by using other toxic compounds, such as benzene, toluene, or xylene (BTX), as the sole source of carbon.

• Clean Technology
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• v.18 no.2
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• pp.200-208
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• 2012

This study was performed to prevent the health damage of environmental contaminants in Industrial Complex Area. And, this study aimed to identify the concentration levels and distribution characteristics of environmental contaminants and Polycyclic Aromatic Hydrocarbons (PAHs) at soil in Industrial Complex Area and control area. The concentration of the soil pollution standard such as the heavy metals in the soil, VOCs, PAHs, and PCB were measured and analyzed using the soil specimens in the Industrial Complex Area and control area. Soil specimens from the Industrial Complex Area (the direct exposure area) and the control area were surveyed. Songdo-dong, Haedo-dong and Jechul-dong, which are in the direct exposure area and near the emission source, showed relatively high concentrations of contaminant materials when compared with Jangki-myeon, which is far off and in the control area. The concentration of zinc was 20.8-58.9% of the level of concern (300 mg/kg) in the 1st region, which is a relatively high concentration. The concentration of fluoride was under the standard in every region, but it was about 74% of the level of concern (400 mg/kg) in the 1st region. It is recommended that controlling fluoride emissions is necessary. Levels of organic phosphate, phenol, and VOCs like benzene, toluene, ethylbenzene and xylene were under the detection limit of the analysis instruments. The concentration of TPH was high in Songdo-dong. The concentration of contaminants in Jechul-dong was high. In addition, it was observed that the level of soil contamination changed depending on the distance from the emission source. The concentration of PAH compounds in the soil was 18.71-1744.59 ng/g, and the concentration of six potential cancer-causing PAH materials was 6.54-695.94 ng/g. The highest concentration was in Songdo-dong. The PAH concentration in the direct exposure area near the complex was relatively high compared to the indirect exposure area.

• Analytical Science and Technology
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• v.11 no.1
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• pp.62-72
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• 1998

This study was performed to characterize the trace organic pollutants in the industrial wastewater and to establish the database of the trace organic pollutants. The four manufacturing industries, which are refined petroleum, industrial chemicals, rubber & plastics and fabricated metals, were surveyed. The wastewater and discharging water of these 30 factories are analyzed to characterize the trace organic pollutants. In industrial chemicals, the kinds of products and organic pollutants are very various. Therefore to select the characteristic organic pollutants in this categories are also very difficult. In industrial chemicals, the gas chromatograpic peak patterns of wastewater are represented the various type according to their products, therefore the typical patterns of the characteristic organic pollutants could not be obtained because the kinds of manufactured goods and organic pollutants are very various. In refined petroleum, the effluent is discharged in the distillatory process of atmosphere pressure and contained the saturated hydrocarbons, phenol compounds, benzene compounds and naphtalene compounds. The saturated hydrocarbons peaks from $C_{15}$ to $C_{35}$ are represented the typical oil patterns by the uniform intervals therefore the peak can be easily distinguished. In rubber & plastics, the wastewater is discharged in the washing process which contains the additives. The problem of wastewater is not serious because the manufacturing process is not produced the effluent or the produced cooling water is recycled in that process.