• Journal of Korea Water Resources Association
• /
• v.36 no.4
• /
• pp.691-703
• /
• 2003

In this paper, a new and integrated approach easily used to calculate the pollutant loads from agricultural watersheds is suggested. Basic concepts of this empirical tool are based on the hypotheses that variations in event mean concentrations(EMCs) of the pollutants from a given agricultural watershed during rainstorms are only due to the rainfall pattern. This assumption would be feasible to agricultural watersheds whose land uses does not change during the cultivation period overlapped by rainy season and also in which point-sources of the pollutants are rare. Therefore, if EMC data sets through extensive sampling from various rural areas are available, it is possible to establish relationships between EMCs, shapes and land uses of the watersheds, and rainfall events. For this purpose, fifty one sets of EMC values were obtained from nine different watersheds, and those data were used to develop predictive tools for the EMCs of 55, COD, TN and TP in rainfall runoff. The results of the statistical tests for those formulas show that they are not only fairly good in predicting actual EMC values of some parameters, but also useful in terms of calculating pollutant loads on any time-spans such as the day of rainfall event or weekly, monthly, and yearly. Their applicability was briefly demonstrated and discussed. Also, the unit loads calculated from EMCs based on different land uses and real rainfall data over one of the watershed used for this study. were provided, and they are compared with other well-known unit loads.

• Journal of Wetlands Research
• /
• v.11 no.2
• /
• pp.67-76
• /
• 2009

The contribution of pollutant loadings from non-point source (NPS) to the four major rivers in Korea exceeded 22~37 % of the total loadings in 2004 and is expected to reach 60 % in 2020. Most of NPS loadings are coming from urban areas, especially from paved areas. Because of high imperviousness rate, many types of NPS pollutant are accumulating on the surface during dry periods. The accumulated pollutants are wash-off during a storm and highly degrading the water quality of receiving water bodies. For this reason, the Korean Ministry of Environment (MOE) developed the Total Maximum Daily Load (TMDL) program to protect the water quality by managing the point source and NPS loadings. NPS has high uncertainties during a storm because of the characteristics of rainfall and watershed areas. The rainfall characteristics can affect on event mean concentrations (EMCs), mass loadings, flow rate, etc. Therefore, this research was performed to determine EMCs for rainfall ranges from transportation landuses such as road and parking lot. Two sites were monitored over 45 storm events during the 2006/06 through 2008/10 storm seasons. Mean TSS EMCs decrease as rainfall ranges increase and highest at less than 10mm rainfall. The results of this study can be used to determine the efficient scale of BMP facility considering specific rainfall range.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.19 no.1
• /
• pp.31-37
• /
• 2021

Purpose: Acetaminophen (APAP) is a widely available drug responsible for a large part of drug-induced hepatotoxicity in developed countries. Although acetaminophen overdose cases in Korea are being continuously reported, there are no reports related to the level of this drug in the patient's blood or of laboratory analysis at emergency departments (ED). This study sought to analyze the acetaminophen overdose cases at a toxicological laboratory and to survey APAP analysis services offered at select EDs. Methods: We analyzed the demographic and analytic data at a toxicological laboratory run by the National Emergency Medical Center (NMC) in 2019-2020. We surveyed the APAP laboratory service in the 38 regional emergency medical centers (EMCs) and 68 local EMCs near the toxicological laboratory. Results: We studied 175 acute poisoning cases (112 women) with positive blood APAP results (mean age 47.0±24.1 years). Suicide attempts comprised 40.0% of the cases and 30.3% APAP overdose events. In the univariate analysis, we observed that patients were significantly younger, with fewer underlying medical diseases. There were a higher number of APAP overdose events, more favorable initial mental status, more toxic quantity intake in the above treatment line group (p<0.05), In multivariate analysis, the toxic amount intake was significantly more frequent in the above treatment line group (p<0.01). Hospital APAP analysis services were available in six EMCs (3/38 regional and 3/68 local). The hospital blood APAP level reporting intervals were shorter than outside-hospital laboratory services (p<0.01, regional 7.0±3.0 vs. 40.6±27.5, local 5.3±3.1 vs. 57.9±45.1 hours). The NMC toxicological laboratory reporting interval was shorter than the other outside-hospital laboratories (p<0.01, regional 5.7±0.6 vs. 50.2±22.7 local 7.5±3.0 vs. 70.5±41.5 hours). Conclusion: Over the treatment line group, toxic amount intake was significantly more frequent. Only six of 106 EMCs have their own APAP analysis service in their hospitals.

• Journal of Korean Society on Water Environment
• /
• v.24 no.2
• /
• pp.169-173
• /
• 2008

A field monitoring was conducted in order to find out the discharge characteristics of non-point source pollutants in the agricultural area. Event Mean Concentration (EMC) of TSS, $BOD_5$, $COD_{Mn}$, TP, TN was calculated based on the monitoring data of 10 rainfall events at agricultural watersheds. A significant relationship was observed from the correlation between EMCs and rainfall characteristics. The result shows that EMC ranges of 95% confidence intervals were 50.5~203 mg/L for TSS, 0.8~14.2 mg/L for $BOD_5$, 4.2~20.7 mg/L for $COD_{Mn}$, 2.4~4.5 mg/L for TN and 0.2~0.5 mg/L for TP, respectively. The correlation coefficients between TSS and TP and between $BOD_5$ and $COD_{Mn}$ were found to be 0.912 and 0.961. But TN was lower correlated with other EMC factors. It was also found that rainfall characteristics was not correlated with EMCs.

• Journal of Environmental Impact Assessment
• /
• v.16 no.6
• /
• pp.525-532
• /
• 2007

In order to establish and implement the total maximum daily load (TMDL) management plan in Korea, it is necessary to set the source units and calculate discharge loads for non-point source pollutants such as BOD, COD, SS, TN and TP. This study analysed the corelation between stormwater runoff characteristics and event mean concentrations (EMCs) of non-point source pollutants. As the result of the corelation analysis, we knew that all the antecedent dry days (ADD) and the rainfall correlated lowly with non-point source pollutants in the urban areas such as resident area, industrial area, business area, road area and parking area. Therefore, it is necessary to get all samples from stormwater starting point to stormwater ending point and standardize the sampling method of stormwater in order to obtain more accurate EMCs for landuse.

• Journal of Industrial Technology
• /
• v.22 no.B
• /
• pp.95-101
• /
• 2002

Much of domestic city is served by combined sewer system rather than separate sanitary or storm sewers. During wet weather, when the volume of sanitary sewage and storm water entering the combined sewers exceeds the system capacity, the system is designed to overflow at several designated CSOs. The objective of this research is to have grasp of characteristics of combined sewer runoff and to evaluate efficiently the intercepted volume of CSOs. During the wet weather in first rainfall, SS load at each site H-1, H-2, and H-3 were 600kg/event, 370kg/event, and 289kg/event, SS load at each site in second rainfall were 216kg/event, 113kg/event, and 37.2kg/event. EMCs at each site were 702mg/L, 816mg/L, 861mg/L in first rainfall and 99.9mg/L, 161.9mg/L, 103.6mg/L in second rainfall, respectively. First flush coefficients b at each site were 0.237, 0.166, and 0.151.

• Journal of Environmental Science International
• /
• v.21 no.8
• /
• pp.977-988
• /
• 2012

This study analyzed the characteristics of stormwater runoff by rainfall type in orchard areas and transportation areas for 2 years(2010~2011year). Effluents were monitored to calculate the Event Mean Concentrations(EMCs) and runoff loads of each pollutant. The pollutant EMCs by volume of stormwater runoff showed the ranges of BOD 0.9~13.6 mg/L, COD 13.7~45.2 mg/L, SS 4.1~236.4 mg/L, T-N 2.123~21.111 mg/L, T-P 0.495~2.214 mg/L in the orchard areas, and was calculated as BOD 2.3~22.5mg/L, COD 4.4~91.1 mg/L, SS 4.3~138.3 mg/L, T-N 0.700~13.500 mg/L, T-P 0.082~1.345 mg/L in the transportation areas. The correlation coefficient of determination in the orchard area was investigated in the order of Total Rainfall(0.81) > Total Runoff(0.76) > Rainfall Intensity(0.56) > Rainfall Duration(0.46) > Antecedent Dry Days(0.27). Also, in the case of the transportation area was investigated in the order of Total Rainfall (0.55) > Total Runoff(0.54) > Rainfall Intensity(0.53) > Rainfall Duration(0.24) > Antecedent Dry Days(0.14). As the result, comparing valuables relating to runoff of non-pollutant source between orchard areas and transportation areas, orchard area($R^2{\geq}0.5$ : X3, X4, X5) was investigated to have more influence of diverse independent valuables compared to the transportation area($R^2{\geq}0.5$ : X3, X4) and the difference of discharge influence factor by the land characteristics appeared apparently.

• Journal of Korean Society on Water Environment
• /
• v.28 no.2
• /
• pp.255-268
• /
• 2012

Nonpoint source pollution has become a concern for water quality in the Han River system, especially during the high runoff events during the monsoon season. The patterns in nonpoint source runoff the relationships with land use, rainfall intensity, and stream nutrients concentrations were surveyed in 19 streams in the Han River watershed. The results show that the magnitude of NPS inputs of nutrients and sediment in the Han River watershed are of a serious concern. In the South Han River watershed, event mean concentrations (EMC) for biochemical oxygen demand (BOD), suspended sediment (SS), dissolved organic carbon (DOC), dissolved total phosphorus (DTP), total nitrogen (TN) Nitrate ($NO_3$-N) and total phosphorus (TP) were $1.94mg{\cdot}L^{-1},\;251mg{\cdot}L^{-1},\;2.75mg{\cdot}L^{-1},\;0.076mg{\cdot}L^{-1},\;2.82mg{\cdot}L^{-1},\;2.40mg{\cdot}L^{-1}$ and $0.232mg{\cdot}L^{-1}$, respectively. In the North Han River watershed, EMCs for BOD, SS, DOC, DTP, TN, $NO_3$-N and TP were $1.34mg{\cdot}L^{-1},\;172mg{\cdot}L^{-1},\;2.63mg{\cdot}L^{-1},\;0.032mg{\cdot}L^{-1},\;1.97mg{\cdot}L^{-1},\;1.55mg{\cdot}L^{-1}$ and $0.148mg{\cdot}L^{-1}$, respectively. The specific export coefficients of nutrient and sediments were much higher than those of other reports. Our study also found that the proportion of agricultural field area was significantly correlated with the EMCs for nutrients. Therefore, efforts to reduce NPS loading must focus on agricultural practices in the watershed. The relationships between land use and nutrient and sediment export found in this study can be used to derive estimates of runoff coefficients for agricultural field and as input data for modeling works and to develop total maximum daily load and best management practices in the Han River watershed.

• Journal of the Microelectronics and Packaging Society
• /
• v.22 no.2
• /
• pp.61-68
• /
• 2015

Warpage analysis has been performed for top and bottom packages of thin package-on-packages processed with different epoxy molding compounds (EMCs). Warpage deviation was measured for packages molded with the same EMCs and also the warpage deviations of top and bottom substrates themselves were characterized in order to identify the major factor causing the package warpage. For the top and bottom packages processed with thin substrates, the warpage deviation of the substrates was large, which made it difficult to figure out the effect of EMC properties on the package warpage. Top packages, where the molding area of $13mm{\times}13mm$ covered the most of the substrate area ($14mm{\times}14mm$), exhibited similar warpage behavior with changing the temperature. On the other hand, bottom packages, where the molding area was only $8mm{\times}8mm$, exhibited the complex warpage behavior due to simultaneous occurrence of (+) and (-) warpages on the same package. Accordingly, the bottom packages showed dissimilar temperature-warpage behavior even being processed with the same EMCs.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.2B
• /
• pp.225-231
• /
• 2006

The nonpoint source control is based on TPLMS (Total Pollution Load Management System) program. Recently, the Ministry of Environment in Korea has programed TPLMS for 4 major large rivers to improve the water quality in rivers by controling the total pollutant loadings from the watershed area. Usually the urbanization is the main pollutant sources, particularly for nonpoint pollutants, because of high imperviousness and high pollutant mass emissions. The stormwater runoff from urban areas is containing various pollutants such as sediments, metals and toxic chemicals due to human and vehicle activities. Of the various landuses, the highways are highly polluted landuses because of high pollutant accumulation rate by vehicle activities during dry periods. Therefore, this research is achieved to provide pollutant EMCs (Event Mean Concentrations) and mass loadings washed-off from highways during rainfall periods. Five monitoring locations were equipped with an automatic rainfall gage and an flow meter. The results show that the EMC ranges for 95% confidence intervals in highway land use are 45.52-125.76 mg/L for TSS, 52.04-95.48 mg/L for COD, 1.77-4.48 mg/L for TN, 0.29-0.54 mg/L for TP. The ranges of washed- off mass loading are $712.7-2,418.4mg/m^2$ for TSS and $684.1-1,779.6mg/m^2$ for COD.