• Membrane and Water Treatment
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• v.10 no.1
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• pp.29-38
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• 2019

Microbial community and composition in stormwater runoff from mixed land use land cover (LULC) catchment with ongoing land development was diverse across the hydrological stage due different environmental parameters (hydrometeorological and physicochemical) and source of runoff. However, limited studies have been made for bacterial composition in this catchment. Therefore, this study aims to: (1) quantify the concentration of fecal indicator bacteria (FIB), stormwater quality and bacterial composition and structure according to hydrological stage; and (2) determine their correlation to environmental parameters. The 454 pyrosequencing was used to determine the bacterial community and composition; while Pearson's correlation was used to determine the correlation among parameters-FIB, stormwater quality, bacterial composition and structure-to environmental parameters. Results demonstrated that the initial and peak runoff has the highest concentration of FIB, stormwater quality and bacterial composition and structure. Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes were dominant bacteria identified in this catchment. Furthermore, the 20 most abundant genera were correlated with runoff duration, average rainfall intensity, runoff volume, runoff flow, temperature, pH, organic matter, nutrients, TSS and turbidity. An increase of FIB and stormwater quality concentration, diversity and richness of bacterial composition and structure in this study was possibly due to leakage from septic tanks, cesspools and latrines; feces of domestic and wild animals; and runoff from forest, destroyed septic system in land development site and urban LULC. Overall, this study will provide an evidence of hydrological stage impacts on the runoff microbiome environment and public health perspective.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.2
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• pp.87-95
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• 2016

Turbidity is a key indicator to the user that the 'Discolored Water' phenomenon known to be caused by corrosion of the pipeline in the water supply system. 'Discolored Water' is defined as a state with a turbidity of the degree to which the user visually be able to recognize water. Therefore, this study used data mining techniques in order to estimate turbidity changes in water supply system. Decision tree analysis was applied in data mining techniques to develop estimation models for turbidity changes in the water supply system. The pH and residual chlorine dataset was used as variables of the turbidity estimation model. As a result, the case of applying both variables(pH and residual chlorine) were shown more reasonable estimation results than models only using each variable. However, the estimation model developed in this study were shown to have underestimated predictions for the peak observed values. To overcome this disadvantage, a high-pass filter method was introduced as a pretreatment of estimation model. Modified model using high-pass filter method showed more exactly predictions for the peak observed values as well as improved prediction performance than the conventional model.

• Korean Journal of Ecology and Environment
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• v.45 no.3
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• pp.289-301
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• 2012

A biological assessment of water quality was made at 9 sites of the Joyang-river and inflow streams located in Jeongseon-gun Gangwon-do, from June 2008 to September 2010. The investigation consisted of physico-chemical factors, biomass, and standing crops of epilithic diatoms. In addition, the community structure of epilithic diatoms was analyzed, and the water quality was assessed using DAIpo and TDI. The pH varied from 7.4~10.2 which is attributed to the Joyang-river area consisting of limestone. A total of 117 taxonomic groups of epilithic diatoms, including: 2 orders, 6 families, 23 genera, 95 species, 15 varieties, 2 forms, and 5 unidentified species, were found in the Joyang-river. 11 taxa, including Achnanthes laterostrata and Cymbella delicatula which live in neutral to alkali pH, were found. An indicator species of alkali waters, Cymbella delicatula, was routinely observed to have a relative frequency of over 10% in I3 and I4. In the result of the biological assessment using DAIpo, the Joyang-river was rated class A, with an average of 77.03 and inflow streams were rated class B with an average of 65.84. As for the results of TDI analysis, the Joyangriver was rated class A~B, and inflow streams were rated class A~D. Accordingly, the water quality of the Joyang-river was determined to be superior to that of inflow streams. Although the main stream showed low water quality at sites J2 and J3, correlating with a reduction in the quality of inflow stream, I1 in September 2009.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.233-238
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• 2008

To evaluate biochemical safety of gejang distributed in Korea, 33 samples were collected and analyzed for indicator microorganisms, pathogen, parasite, pH, volatile basic nitrogen(VBN), salinity, 3-MCPD, histamine, and synthetic food colors. Total plate counts of gejang were the range of 3 to 7 log cfu/g and coliform were the range of ND to 4 log cfu/g. Vibrio parahaemolyticus was detected from 4 samples, and Escherichia coli(1 log cfu/g) and copepoda were detected from 1 sample among those. pH and VBN value of samples were the range of 6.69 to 8.10 and 21.99 to 94.55 mg%, respectively. The ranges of salinity concentration for ganjang chamgejang, ganjang ggokgejang, and ganjang dolgejang were $11.6{\sim}32.6%,\;2.8{\sim}20.5%$, and $11.6{\sim}13.3%$, respectively. But, the range of salinity concentration of yangnum gejang was $2.6{\sim}9.4%$, which was lower than ganjang gejang. Besides, 3-MCPD, histamine and synthetic food colors were not detected. From the results, most of gejang was appropriate for Korea national standard for food regulation, but still biological hygiene control for raw materials, processing, and distribution should be improved.

• Journal of Environmental Health Sciences
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• v.28 no.3
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• pp.1-8
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• 2002

The experiments for the characterization of inactivation were performed in a series of batch processes with the total coliform as a general indicator organism based on chlorine, chlorine dioxide and ozone as disinfectants. The water sam-ples were taken from the outlet of settling basin in a conventional surface water treatment system that is provided with the raw water drawn from the mid-stream of the Han River. The inactivation of total coliform was experimentally ana-lyzed for the dose of disinfectant contact time, pH, Temperature and DOC. The nearly 2.4,3.0,3.9 log inactivation of total coliform killed by injecting 1 mか1 at 5 minutes for chlorine, chlorine dioxide and ozone. For the inactivation of 99.9%(3 log), Disinfectants required were 1.70, 1.00 and 0.60 mか1 for chlorine, chlorine dioxide and ozone, respec-tively. The higher the pH is, the poorer the disinfections effects are in the range of pH 6-9 by using chlorine and ozone. But the irfluence of pH value on killing effects of chlorine dioxide is weak. The parameters estimated by the models of Chick-Watson, Hom, and Selleck from our experimental data obtained for chlorine are: log(N/ $N_{0}$ )=-0.16 CT with n= 1, log(N/ $N_{0}$ )=-0.71 $C^{0.87}$T with n$\neq$1, for Chicks-Watson model, log (N/ $N_{0}$ )= -1.87 $C^{0.47}$ $T^{0.36}$ for Hom model. For chlorine dioxide are: log(N/ $N_{0}$ )= -1.53 CT with n = 1, log(N/ $N_{0}$ )= -2.29 $C^{0.94}$T with n$\neq$1,, for Chicks-Watson model, log(N/ $N_{0}$ )= -3.64 $C^{0.43}$ $T^{0.24}$ for Hom model and for ozone are: log(N/ $N_{0}$ )= -2.59 CT with n = 1, log(N/ $N_{0}$ )= -2.28 $C^{0.36}$T with n$\neq$1, for Chicks-Watson model, log(N/ $N_{0}$ )= -4.53 $C^{0.26}$ $T^{0.19}$ for Hom model.19/ for Hom model.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.2
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• pp.137-141
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• 1971

In order to observe the effect of soil added to oil cake in the preparation of liquid fertilizer for flower culture use, a laboratory experiment was carried out, in addition to a pot experiment done with Petunia as an indicator plant. The results obtained are as follows; 1. Faster decaying, and heavier accumulation of ammonia was observed in the mixture of soil, oil cake and water than the mixture of only oil cake and water. At the same time, the former gave better effect on the growth of Petunia than the latter. It was considered that the early raise of pH in the mixture of soil, oil cake and water stimulated the decomposition of oil cake. 2. No pH raise and a small accumulation of ammonia even at the mixture of soil, oil coke and water was observed when temperature was low, around $12-25^{\circ}C$. However, the deficiency of ammonia in the mixture of soil, oil cake and water was large enough to result in the better growth of Petunia than in the mixture without soil.

• Journal of Life Science
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• v.31 no.12
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• pp.1072-1078
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• 2021

The oral pathogen Streptococcus mutans is considered a major causative agent of dental caries in humans. The use of dental hygiene products, including toothpaste and mouthwash, is used for caries control. However, food intake can lead to the recurrence of oral microorganisms. This study aimed to explore why this bacterium dies so quickly during prolonged incubation and to assess whether this growth characteristic is closely associated with the secretion of metabolic products. Notably, the number of live S. mutans cells rapidly declined after 24 hr during the entire period tested, whereas the number of Escherichia coli cells, an indicator strain, remained steady over the same period. To test whether the S. mutans supernatants contained possible signals that accelerated the death of neighbor cells, we obtained the individual supernatants at the above time points. Following pH neutralization, the cells in which the supernatant was supplemented with glucose grew well. However, pH adjustment alone could not fully recover cell growth in conditions in which the supernatant was supplemented, with or without glucose. These phenotypes of S. mutans may be associated with signaling, not only resulting from nutrient depletion. The findings on the survival phenotype of S. mutans provide new insights into cell-cell communication in the biology of this bacterium.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.5-11
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• 2022

This research evaluated the long-term application effects of different soil amendments on yield, dissolved organic carbon, nitrogen and soil organic carbon stock in rice paddy. The experiment consisted of four different fertilizations; Inorganic fertilization (NPK), NPK+Lime (NPKL), NPK+Silicate (NPKS), NPK+Compost (NPKC). There was no significant difference in rice yield between the treatment groups in 1995, but the rice yields in the NPKL and NPKC treatments in 2019 increased by 4.3% and 14.3% compared to NPK. In terms of soil properties, the pH of NPKS(6.7) and NPKL(6.4) in 2019 increased the most compared to the soil pH before experiment(5.2). The organic matter(OM) content from NPKC treatment increased upto 34 and 27 g kg^-1 in year of 1995 and 2019, respectively, compared to before the test. In NPKS and NPKL treatment, labile carbon and nitrogen content, used as a soil quality indicator, increased by 1.1-1.9 times over the control. From these result, it is suggested that type and application rate of soil amendment should be determined based on the soil analysis before cultivation for sustainable agricultural environment and productivity.

• The Korean Journal of Ecology
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• v.28 no.6
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• pp.389-393
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• 2005

This study was carried out to investigate the effects of soil acidification on the growth of 3-year-old Pinus densiflora seedlings grown for 21 weeks in brown forest soils acidified with $H_2SO_4$ solution. The concentrations of Al in the acidified soils were increased with increasing amount of $H^+$ added to the soil. The total dry weight of the seedlings was reduced by the addition of the $H_2SO_4$ solution. In addition, there was a strong positive correlation (r=0.97, p<0.01) between the dry weight of the seedlings and the molar (Ca+Mg+K)/Al ratio of the soil. The seedlings with the molar (Ca+Mg+K)/Al ratio of 1.0 resulted from approximately 50% growth reduction compared with the control value. The results suggest that the molar (Ca+Mg+K)/Al ratio of the soil may be a useful indicator for assessing the critical load of acid deposition.

• Food Science and Preservation
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• v.30 no.2
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• pp.311-320
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• 2023

Surfactin, one of the most powerful biosurfactants, can be widely applied in agriculture, food, and pharmaceutics. The purpose of the present study was to establish suitable indicators for a rapid detection method that can confirm the surfactin productivity of cheonggukjang. In the present study, changes in the total number of bacteria were quantified according to the fermentation time of chenggukjang. Furthermore, physicochemical factors, such as pH, color value, surface tension, refractive index, absorbance, and protein contents, were assessed in chenggukjang viscous substances, and a correlation analysis between the physicochemical factors and surfactin contents was performed. We found that the protein contents gradually increased up to 48 h (4.21±0.11 mg/mL) without a change in the surface tension. Furthermore, the refractive index, absorbance at 280 nm, and color value were significantly increased as the fermentation time increased; however, there were no statistically significant differences after 36 h of fermentation. Interestingly, this result exhibited a tendency similar to the surfactin content according to fermentation time. These findings suggest that surfactin can be used as a suitable quality indicator and may provide an experimental basis for the fermented food industry.