• Journal of the Korean earth science society
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• v.23 no.5
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• pp.424-435
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• 2002

This study analyzes the surface ozone and meteorological data in Daegu for a period from 1997 to 1999. It also investigates the meteorological characteristics of high ozone episodes. For this study the high ozone episode has been defined as a daily maximum ozone concentration higher than 100ppb in at least one station among six air quality monitoring stations in Daegu, Korea. The frequency of episodes is 13 days. The frequency is the highest in May and September. The average value of daily maximum ozone concentration is 81.6ppb, and 8-hour average ozone concentration is 58.6ppb for the high episodes. This shows that ozone pollution is continuous and wide-ranging in Daegu. The daily maximum ozone concentration is positively correlated to solar radiation and daily maximum temperature, but negatively correlated to relative humidity, wind speed and cloud amount. The maximal correlation coefficient to solar radiation is 0.45. The differences between high ozone episode day's daily mean meteorological value and monthly mean value are +1.58hPa for sea level pressure, +3.45${\circ}$C for maximum temperature, -5.69% for relative humidity, -0.46ms$^{-1}$ for wind speed, -1.79 for cloud amount, and +3.97MJm$^{-2}$ for solar radiation, respectively. This shows that strong solar radiation, low wind speed and no precipitation between 0700${\sim}$1100LST are favorite conditions for high ozone episodes. It is related to the morning stagnant condition.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.104-115
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• 2014

Abundance and composition of marine debris on 13 beaches of Tongyeong City, South Korea were surveyed in 2013 Autumn. The average quantity of macro debris (>25 mm) was about 30 particle/$m^2$ and that of micro debris (1 mm-25 mm) was about 26,971 particle/$m^2$. This is a very high level compared with other areas of South Korea and the other countries. Among the 7 material types of debris (styrofoam, hard plastic, fiber, metal, glass, wood and others), styrofoam composed a large portion: 75% of macro debris and 98% of micro debris. And among the 'whole' styrofoam debris items whose original volume is remained more than 50%, styrofoam buoy debris composed 93%. This result suggests that the beaches surveyed are seriously contaminated by marine debris, and most of its sources are aquaculture styrofoam buoys. Management of styrofoam buoy debris used for oyster aquaculture in Tongyeong City is important not only for Tongyeong city, but also for other areas, because Tongyeong city hosts the biggest number of oyster aquaculture areas in South Korea.

• Journal of Environmental Science International
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• v.2 no.2
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• pp.29-29
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• 1993

Shingal reservoir is a relatively small (211ha) and shallow impoundment, and approximately 25 ha of its sediment is exposed after spring drawdown. At least 14 vascular p13n1 species germinate on the exposed sediment, but Persimria vulgaris Webb et Moq. quickly dominates the vegetation. In order to estimate the role of the vegetation in the dynamics of heavy metal pollutants in the reservoir, Cu concentration of water, fallout particles, exposed sediment, and tissues of p. vulgaris, Ivas analyzed. Cu content in reservoir water decreased from $13.10mg/m^2$ on May 15 (before dralvdown) to $3.08mg/m^2$ in June 1 (after drawdown), mainly due to the loiwering of water level. Average atmospheric deposition of Cu by fallout particles was $10.84 {\mu}g/m^2/day$. Cu content in the surface 15cm of exposed sediment decreased from $5.094g1m^2$ right after drawdown, to $0.530g/m^2$ in 41 days, which is a 89.6% decrease. Therefore up to 99.7% of Cu in the reservoir appears to exist in the sediment. only 0.3% in water If the rate of atmospheric Input by fallout particles is assumed to have been the same since 1958, when the reservoir was completed, cumulative input of Cu during the 38 years would have been $150.35mg/m^2$, which is only 3.0% of Cu content in sediment right after drawdown. Therefore, most of Cu in the Shingal reservoir must have been transported by the Shingal-chun flowing into the reservoir, Standing crop of vegetation on the exposed sediment 41 days after drawdown was $730.67g/m^2$, of which 630.91g/m2 was p. vulgaris alone, and Cu content in P vulgaris at this time was $6.612mg/m^2$. This was only 0.13% of Cu in the exposed sediment, but was 50.5% of Cu in water before drawdown, or 167% of the average annual input of Cu by atmospheric deposition. If other plants were assumed to absorb Cu to the same concentration as p. vulgaris, total amount of Cu absorbed in 41 days by vegetation on the exposed sediment is estimated to be 1913.3 g, which is a considerable contribution to the purification of the reservoir water.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.979-985
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• 2010

This study was performed to detect enterococci strain as an indicator of faecal contamination, to identify of 16S rDNA sequence and vancomycin resistance by MIC (Minimum Inhibitory Concentration) test from drinking spring-water samples in Seoul. The detection frequency of enterococci was 42 (19.8%) among 212 samples, and its concentration was ranged from 0 to 110 CFU/100 mL. These results were confirmed the possibility as an indicator microorganisms that similar to the frequency of E. coli detection (t test p-value 0.268, significant level 0.05). Isolated 56 enterococci samples were identified by 16S rDNA sequence data and their NCBI BLAST searching. They were identified to Enterococcus faecalis of 24 samples, E. faecium (10), E. casseliflavus (10), E. gallinarum (3), E. hirae (2), E. durans (2), E. sanguinicola (1). E. faecalis was dominant species that clinical case report of a domestic was similar. Vancomycin resistant enterococci (VRE) of 53 samples showed that vanB and vanC1/C2 type with 2 and 12 case, respectively. These results indicated that the drinking spring-water quarantined to fecal pollution for block out outbreak of gastrointestinal symptom with using such as disinfection process.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.412-420
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• 2014

Water quality variations were investigated at 4 locations of Jungrang river (upper, middle and lower basins) during a period of 3 rainfall events. During the rainfall, concentrations of $COD_{Mn}$, SS and $BOD_5$ significantly increased, while the concentration of T-N decreased and that of T-P remained relatively constant. This pattern became more apparent as the level of accumulative precipitation and rainfall intensity increased. Simple regression analysis showed that the accumulative precipitation was positively correlated with all water quality pollutants except for T-N. With increasing accumulative precipitation, the concentration of T-N decreased, while the others increased. $R^2$ of simple regressions of hourly average rainfall intensity and water quality pollutants, showed wider range of variation ranged from 0.483 to 0.992, which indicated a strong correlation. The stronger the hourly average rainfall intensity, the more T-N and T-P in the upper basin, more $COD_{Mn}$ in the middle and lower basins, more SS with gradual increase from upper to lower areas, and more $BOD_5$ with gradual decrease from upper to lower region. Simple regression showed that water quality pollution in the upper basin was more sensitive to an increase of rainfall discharge than that in the middle and lower areas.

• Journal of Korean Society of Transportation
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• v.35 no.3
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• pp.220-233
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• 2017

Traffic volumes are fundamental data widely used in various traffic analysis, such as origin-and-destination establishment, total traveled kilometer distance calculation, congestion evaluation, and so on. The low number of links collecting the traffic-volume data in a large urban highway network has weakened the quality of the analyses in practice. This study proposes a method to estimate the traffic volume data on a highway link where no collection device is available by introducing a spatial statistic technique with (1) the traffic-volume data from TOPIS, and National Transport Information Center in the Ministry of Land, Infrastructure, and (2) the navigation data from private navigation. Two different component models were prepared for the interrupted and the uninterrupted flows respectively, due to their different traffic-flow characteristics: the piecewise constant function and the regression kriging. The comparison of the traffic volumes estimated by the proposed method against the ones counted in the field showed that the level of error includes 6.26% in MAPE and 5,410 in RMSE, and thus the prediction error is 20.3% in MAPE.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.632-640
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• 2017

In order to understand the seasonal and geographical characteristics of environmental factors and distribution of Escherichia coli by salinity gradient due to precipitation, we investigated abiotic and biotic factors during four seasons from February 2013 to November 2015. The study area was divided into three different zones based on salinity gradient and geo-oceanographic characteristics. During the study period, water temperature, salinity, Chlorophyll a, and secchi-depth varied in the range of $8.5-26.1^{\circ}C$, 13.5-34.4 psu, $0.4-74.0{\mu}g\;L^{-1}$, and 0.5-10.0 m, respectively. Salinity was low at Zone I, which was influenced by water flux from Tae-hwa River, especially in 2014. Salinity was gradually increased (one-way ANOVA; p < 0.05) toward Zone III located offshore of the bay. The highest colony form of E. coli was detected at Zone I. E. coli maintained a relatively low level at Zone III during all seasons. E. coli was correlated with transparency (r = -0.36; p < 0.05) and salinity (r = -0.53; p < 0.01), implying that those parameters might play important roles in the proliferation of E. coli. These results indicated that E. coli were strongly affected by frequent rain (< 50 mm) around inner stations in Ulsan Bay of Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1035-1039
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• 2010

For 65 national forest areas in 1993 to 2008, the ambient sulfur dioxide ($SO_2$) concentrations were measured monthly using passive samplers and compared to the those of urban areas in order to investigate the characteristics of temporal and spatial distribution. In the forest areas, annual average concentration of sulfur dioxide gradually decreased from the beginning year of monitoring to 1997 and then had no significant change, such as the annual trend in urban areas monitored by Ministry of Environment. For the monitoring term, average concentration of sulfur dioxide in the forest areas was 5.6ppb, which was lower than the 10.1ppb in the urban areas and the EC ecological standard level (7.6 ppb). Seasonally, both in forest areas and urban areas the monthly average concentrations were much higher in winter and spring due to much more heating fuel consumption, and lowest in summer. Regional comparison to other regions of Gyeongbuk and Gyeonggi province showed that the concentration of sulfur dioxide was the highest during year. A significant positive correlation between sulfur oxides' emissions and sulfur dioxide concentration by province was observed, reflecting that the size and proximity of sources of atmospheric sulfur oxides could be important factors in determination.

• Korean Journal of Pharmacognosy
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• v.52 no.4
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• pp.219-227
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• 2021

By analysing the benzo(a)pyrene concentration using HPLC-FLD and LC-MS/MS, pollution levels of herbal medicines without permitted benzo(a)pyrene specification were investigated. Average benzo(a)pyrene concentrations were 38.30, 37.46 and 21.22 ㎍/kg for Amomi Tsao-ko Fructus, Mume Fructus and Coptidis Rhizoma, respectively, which are 4 to 7 times higher than maximum permitted benzo(a)pyrene concentration of Rehmanniae Radix Preparata and Rehmanniae Radix, i.e. 5.0 ㎍/kg. Proportion of detected samples exceeding 5.0 ㎍/kg benzo(a)pyrene concentration was 22% for Cimicifugae Rhizoma and Scrophulariae Radix, 44% for Forsythiae Fructus, 67% for Mume Fructus, 100% for Amomi Tsao-ko Fructus and Coptidis Rhizoma, and collectively 29% (36 out of 125 samples) in average. In terms of risk characterization results, human exposure of benzo(a)pyrene were 7.96, 3.49 and 1.61 ng/kg b.w./day and the margin of exposure(MOE) were 1.25 × 10⁴, 2.86 × 10⁴ and 6.20 × 10⁴ for Mume Fructus, Amomi Tsao-ko Fructus and Coptidis Rhizoma, respectively. MOE banding of those herbal medicines was categorized to 'low concern'. However, considering that human exposure of benzo(a)pyrene for food is legislated to 1.4~2.5 ng/kg b.w./day, it was urgent to set up the guideline of benzo(a)pyrene in herbal medicines.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.2
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• pp.82-95
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• 2021

We investigated the temporal and spatial distribution characteristics of chemical oxygen demand (COD) and total organic carbon (TOC) in all 13 locations of Masan Bay from February to November in 2015. The COD and TOC contents were high during the June-August period when the pollution load increased. In particular, the concentrations of COD and TOC were about twice as high in the surface water as in the bottom water. In spatial distribution, the COD and TOC concentrations at the inner bay were about twice as high as those of the outer bay in Masan Bay. As a result of estimating the oxidation efficiency of COD from the surface layer of Masan Bay in 2015 based on the theoretical oxygen demand (TOD), it was at the level of about 23%. Due to the low oxidation efficiency of COD, there is a risk that the organic matter in Masan Bay will be somewhat underestimated. Therefore, for quantitative analysis of organic matter, COD and TOC analyses need to be combined.