• Journal of Environmental Health Sciences
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• v.43 no.3
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• pp.167-175
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• 2017

Objectives: Children may be more exposed to certain environmental contaminants because they react with greater sensitivity and have different food intakes and breathing rate per unit of body weight compared to adults. The aim of this study was to determine general exposure factors such as skin surface area, period and frequency of exposure, and others among Korean children aged ${\leq}18$ years old. This study was carried out as the first of its kind in Korea. Methods: We developed 23 recommended exposure factors for Korean children aged 0 to 18 years by reclassifying raw data from the National Health and Nutrition Examination Survey and the National Statistical Information Service, as well as through investigation by experiments in the absence of related data. Results: Reflecting the activity patterns of about 9,000 children, the daily inhalation rates for long-term exposure ranged from $9.49m^3/day$ for children from birth to <2 years to $14.98m^3/day$ for children aged 16 to <18 years. The research found that Korean children spent an average of 22.21 hours indoors, 0.67 hours outdoors, and 1.12 hours in-transit every day. Young children (${\leq}2$ years old) spent approximately 34 more minutes outdoors on weekends than they did on weekdays. Conclusion: Various physiological variables in the human body reflect characteristics of children that can directly influence risk exposure. Therefore, the identification of general exposure factors based on Korean children is required for appropriate risk assessment.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.52-61
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• 2012

Distribution, abundance and biomass of submerged macrophytes were assessed using a double-headed rake and an echo-sounder in the Keumpoong Reservoir to investigate the temporal and spatial variations of submerged macrophytes in a small agricultural reservoir located upstream. Slope steepness and water depth in the littoral zone were important controlling factors on flora and vegetation structure of submerged macrophytes. Biodiversity of submerged macrophytes was increased at a gentle slope of the littoral zone. The results of DCA (detrended correspondence analysis) showed that the structure of submerged vegetation depended on the depth of water. Submerged macrophytes were distributed at the maximum water depth of 2.8 m in the Keumpoong Reservoir. The area occupied by the submerged macrophytes was estimated at only 6% of the total reservoir area because of the steep slope of the littoral zone and the large annual water-level fluctuation of 3.5 m. The increase of water level and inflow of turbid water in the rainy season might reduce the biomass of submerged macrophytes in the reservoir. It may be concluded that submerged vegetation in the Keumpoong Reservoir, a small agricultural reservoir located at the upstream, appears to be particularly susceptible to water level fluctuations and slope steepness of the littoral zone.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1104-1110
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• 2007

The number of investigated fish collected from the Andong and the Imha reservoir were 2,540 individuals 20 species belonging to 7 families, 850 individuals 11 species belonging to 4 families respectively from May 2005 to March 2006. The total number of the common 3 species individuals investigated caught from the Andong reservoir and the Imha reservoir were 486 individuals and 124 individuals respectively. The investigated individuals is similar(${\pm}2.5$ mm) to 171 individuals make a comparative study. The Opsariichthys uncirostris, Culter brevicauda, Hemiculter eigenmanni of length-weight relationship were TW = $0.00007TL^{3.0543}$, TW = $0.0000009TL^{3.3654}$, TW = $0.00000^{3.3872}$ in the Andong reservoir and TW = $0.00002TL^{2.8493}$, TW = $0.00001TL^{2.8744}$, TW = $0.000004TL^{3.1082}$ in the Imha reservoir respectively. The Condition factor(K) of the Andong reservoir showed the positive slopes in all three species and to be in a good nutrition condition; where as the condition factor(K) of the Imha reservoir showed the negative slopes in two species except in H. eigenmanni and appeared to be in a little bad nutrition condition. Relative condition factor(Kn) indicating that O. uncirostris and C. brevicauda in Andong reservoir is more rotund than ones of Imha reservoir but H. eigenmanni in the Imha reservoir is more rotund than the ones of the Andong reservoir.

• Journal of Environmental Health Sciences
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• v.42 no.1
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• pp.10-18
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• 2016

Objectives: Microcystin (MC) produced during cyanobacterial blooms is a worldwide problem presenting a serious health threats to humans and ecosystems. During July through October of 2013, the Ilwol Reservoir experienced a high biomass of phytoplankton (maximum $211.7mg/m^3$ of Chlorophyll-a) containing the toxigenic cyanobacterium Oscillatoria sp. The aim of this study is to analyze MC concentration in the reservoir water, as well as in representative fish species (Carassius cuvieri, Carassius auratus, Channa argus). We also evaluated the human health risk of exposure to MCs accumulated in the fish. Methods: Concentrations of MCs in the water and fish samples were analyzed by liquid chromatography with a triple quadrupole tandem mass spectrometer (LC/MS/MS) and enzyme-linked immunosorbent assay (ELISA). Results: The total levels of four MC variants, including MC-LR, MC-RR, MC-YR and MC-LA were below the WHO drinking water guideline limit (1 ug MC-LR per liter) both for the dissolved and particulate fraction present in the water samples. The mean MC concentrations in the livers of all species were significantly higher than in the gills (p < 0.01) and muscles (p < 0.05). The values of estimated daily intake of MCs in muscles, the edible part of the fish, would be only $0.005-0.015{\mu}g/kg{\cdot}day$, much lower than WHO's provisional tolerable daily intake of $0.04{\mu}g/kg{\cdot}day$. Conclusion: This study suggests that, owing to the spatial distribution or temporal variation of MC, there is a need for careful monitoring of cyanotoxin in reservoir water and aquatic animals to protect public health.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.381-386
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• 2012

This study was carried out to clarify the turbidity change on three stands (Castanea crenata, Pinus densiflora and Plantation Land) by rainfall characteristics in small watershed. The change of turbidity showed in order of plantation land, Castanea stand and Pinus stand. The linear equations models between turbidity and rainfall intensity were able to account for 91% in Castanea stand, 80% in Pinus stand and 71% in plantation land. The linear equations models between turbidity and duration of rainfall were able to account for about 0-1% in three stands. The linear equations models between turbidity and preceding dry days were able to account for about 30% in three stands. The linear equations models between turbidity and accumulative rainfall were able to account for about 6-22% in three stands. The results indicates that soil runoff by land use and development of forest area could be applied to the mitigation measures such as afforestation and erosion check dam for erosion control and water quality management in small watershed.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.574-578
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• 2012

This study was carried out to clarify the influences of forest environmental factors on turbidity of Stream water on three stands (Castanea crenata, Pinus densiflora and Plantation Land) of small watershed in Samgyeri Naedong-myeon Jinju-si Gyeongsangnam-do. The relationship between turbidity and forest environmental factors was a positive correlation at 1% level with chromaticity, suspended solid, sediment runoff erosion, slope, rainfall intensity, preceding dry days, watershed area and stream length and at 5% level with accumulative rainfall. The important factors that affected turbidity in small watershed showed in order of preceding dry days, rainfall intensity, stream length, chromaticity and suspended solid. In the stepwise regression between turbidity and forest environmental factors, the estimation equation is as follow; Y=-28.125+0.047x (suspended solid)+0.058x (chromaticity)+1.518x (rainfall intensity)+0.264x (stream length)+1.837x (preceding dry days). The results indicates that dangerous areas of landslide and soil runoff by land use could be applied to the mitigation measures such as afforestation, erosion check dam and revetment for erosion control and water quality management in small watershed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.267-276
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• 1979

This research was conducted to evaluate tile effects of polluted Suyeong River water on the water quality of Kwangan-Ri bathing beach. The quantity of pollutant loading of Suyeong River was determined in January 1979, and the directions of tidal currents and the chemical constituents of the Suyeong Bay water were observed in May 1979. The results are as follows: The quantity of total pollutant loading which was discharged into Suyeong Bay is: BOD 75.2ton/day; COD 96.9ton/day; SS 20.5ton/day; ammonia-nitrogen 12.4ton/day; nitrate-nitrogen 430kg/day; nitrite-nitrogen 85.1kg/day; phosphate-phosphorus 594kg/day and total heavy metals 3.01ton/day. Considering the tidal current, the polluted waters of Suyeong River flow off the Kwangan-Ri beach during tile ebb tides, and flow into the Kwangan Ri beach during the flood tides. Consequently, the water quality of Kangan-Ri bathing beach is not suitable for bathing.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.822-828
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• 2005

The photocatalytic degradation of methyl parathion was carried out using a circulating $TiO_2$/solar system. Under the photocatalytic condition, parathion was more effectively degraded than by the photolysis or $TiO_2$ only condition. The parathion degradation followed pseudo first-order kinetics. With photocatalysis, 10 mg/L parathion was completely degraded within 90 min with a TOC decrease exceeding 63% after 150 min. The nitrogen from parathion was recovered mainly as ${NO_2}^-$, ${NO_3}^-$, and ${NH_4}^+$, 80% of sulfur as ${SO_4}^{2-}$, and less than 5% of phosphorus as ${PO_4}^{3-}$ during photocatalysis. The organic intermediates 4-nitrophenol and paraoxon were also identified, and these were further degraded. Two different bioassays using V. fischeri and D. magna were employed to measure the toxicity reduction in the solutions treated by both photocatalysis and photolysis. Relative toxicity was reduced almost completely after 150 min in both organisms under the photocatalysis, whereas in photolysis, 76 and 57% reduction was achieved for V. fischeri and D. magna, respectively. The acute toxicity reduction pattern corresponded with the decrease in parathion and TOC concentrations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.493-499
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• 2008

This study was performed to estimate the water quality parameters on corrosion such as pH, turbidity, Fe released concentration, corrosion rate by using batch reactor for corrosion control of phosphate corrosion inhibitor in carbon steel pipes. The pH, conductivity, alkalinity, and Ca hardness showed a slight change for dosing the phosphate corrosion inhibitor with carbon steel pipe in batch reactor. The turbidity was about ten times lower with 5 mg $P_2O_5/L$ of the corrosion inhibitor than that without. The Fe released concentration and corrosion rate was decreased by about 12.2, 24 times with 5 mg $P_2O_5/L$ of the corrosion inhibitor than that without. In conclusion, the optimum concentration of the phosphate corrosion inhibitor was found to be 5 mg $P_2O_5/L$. The effect of the corrosion inhibitor was significant for the carbon steel plate samples tested in this study. The corrosion inhibitor can be an effective cure for corrosion and red water problem preventing the service pipe from further corrosion.

• Pediatric Infection and Vaccine
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• v.3 no.2
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• pp.168-174
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• 1996

Purpose : Aseptic meningitis is relatively frequent in children and caused mostly by enterovirus. The aim of the present study was to determine the effect of early diagnosis (spinal tapping) on symptom duration of childhood aseptic meningitis. Methods : One hundred fifty-three children who were hospitalized due to aseptic menigitis in the Department of Pediatrics St. Benedict Hospital from July 1996 through October 1996 were included in this study. Patients were divided to two groups according to the duration from first symptom onset to diagnosis. Early diagnosis group is diagnosed within 3 days from first symptom onset. Later diagnosis group is diagnosed after 4 days from first symptom onset. Results : 1) The average age of these patients was 4.3 years old in early diagnosis group and 4.1 years old in later diagnosis group. The sex ratio(male: female) was 2.04:1 in early diagnosis group and 2.5:1 in later diagnosis group. 2) The mean duration of diagnosis of this study was 2.04 day in early diagnosis group and 5.12 day in later diagnosis group. 3) The percentage of symptom and sign of the early diagnosis group were fever(100%), headache(88.4%), vomiting(86.9%), abdominal pain(39%), neck stiffness(36.2%), skin rash(18.8%), diarrhea(16.9%) and that of later diagosis group were fever(100%), headache(83.3), vomiting(80.9%), abdominal pain(47.6%), neck stiffness(41.6%), skin rash(29.7%), diarrhea(16.6%). 4) Initial CSF findings revealed leukocyte $146.8{\pm}386.3/mm^3$ with PMNL 38%, protein 32.47mg/dl, sugar 66.23mg/dl in early diagnosis group and leukocyte $458.1{\pm}663.2/mm^3$, protein 31.22mg/dl, sugar 64.21 mg/dl in later diagnosis group. 5) There was no statistically significant differance in the peripheral blood findings between early diagnosis group and later diagnosis group. 6) The duration of disappearance of symptom after spinal tap were 2.3 days in early diagnosis group and 2.24 days in later diagnosis group. Total symptom duration was 4.34 days in early diagnosis group and 7.36 days in later diagnosis group. Conclusions : Our results demonstrate that early diagnosis(early spinal tap) shortened duration of clinical symptoms.