• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.45-56
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• 2013

This study was suggested as fundamental data to control medical materials remained in Nakdong range gauge. The level of Iopromide detected in Nakdong mainstream was $0.0015{\sim}0.37{\mu}g/L$, Mefenamic acid $0.0087{\sim}0.056{\mu}g/L$, Diclofenac $N.D.{\sim}0.01{\mu}g/L$, Atenolol $N.D.{\sim}0.024{\mu}g/L$, Propranolol $N.D.{\sim}0.0038{\mu}g/L$, Lincomycin $0.0005{\sim}0.038{\mu}g/L$, and Trimethoprim $N.D.{\sim}0.0083{\mu}g/L$. At sewage disposal plant in the region, most of them were detected high levels of density. Especially, the level of Iopromide was found the highest up to $5.38{\mu}g/L$. At livestock wasted water disposal plant, the level of lincomycin was detected the highest figure of $477{\mu}g/L$. As a result, medical materials from Nakdong River mainstream got increasing the concentration due to inflow from sewage disposal plant in Gumi and River Geumho in Daegu, which affects residential and industrial areas significantly. Therefore, to control medical materials remained in Nakdong River efficiently, Geumho River and sewage disposal plants shall be continuously monitored and managed, which is recommendable.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.154-160
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• 2017

BACKGROUND:This study was carried out to establish an efficient sample preparation for the simultaneous determination of bisphenols (BPs) in river water samples using gas chromatography-mass spectrometry (GC-MS). Sample preparation was examined with conventional extraction methods, such as solid-phase extraction (SPE) and liquid-liquid extraction (LLE), and their efficiency was compared with validation results, including linearity of calibration curve, method detection limit (MDL), limit of quantification (LOQ), accuracy, and precision. METHODS AND RESULTS:The BPs (bisphenol A, BPA; bisphenol B, BPB; bisphenol C, BPC; bisphenol E, BPE; bisphenol F, BPF; bisphenol S, BPS) were analyzed using GC-MS. The range of MDLs by SPE and LLE methods was $0.0005{\sim}0.0234{\mu}g/L$ and $0.0037{\sim}0.2034{\mu}g/L$, and that of LOQs was $0.0015{\sim}0.0744{\mu}g/L$ and $0.0117{\sim}0.6477{\mu}g/L$, respectively. The calibration curve obtained from standard solution of $0.004{\sim}4.0{\mu}g/L$ (SPE) and $0.016{\sim}16{\mu}g/L$ (LLE) showed good linearity with $r^2$ value of 0.9969 over. Accuracy was 93.2~108% and 97.4~120%, and precision was 1.7~4.6% and 0.7~6.5%, respectively. The values of MDL and LOQ resulted from the SPE method were higher than those from the LLE method, particularly those values of BPA were highest among the BPs. Based on the results, the SPE method was applied to determine the BPs in river water samples. Water samples were collected from mainstream, tributary and sewage wastewater treatment plants (SWTPs) in the Yeongsan river basin. The concentration of BPB, BPC, BPE, BPF and BPS were not detected in all sites, whereas BPA was ranged $0.0095{\sim}0.2583{\mu}g/L$, which was $0.0166{\sim}0.0810{\mu}g/L$ for mainstreams, $0.0095{\sim}0.2583{\mu}g/L$ for tributaries, $0.0352{\sim}0.1217{\mu}g/L$ for SWTPs. CONCLUSION: From these results, the SPE method was very effective for the simultaneous determination of BPs in river water samples using GC-MS. We provided that it is a convenient, reliable and sensitive method enough to monitor and understand the fate of the BPs in aquatic ecosystems.

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.236-241
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• 2005

The purpose of this study is to find out the source(s) and distribution of boron in Nak-dong River. In the year of 2002, the boron has been adopted as a toxic constituent for Korean drinking water standard. In this study, the analytical samples were collected at 11 stations in March, June, September and December 2002. These samples were analyzed by inductively coupled plasma-mass (ICP-MS) method. The recovery, relative standard deviation and method detection limit of the ICP-MS method for boron was $89{\sim}111.3%$, $2.21{\sim}3.81%$ and $5{\mu}g/L$, respectively. The distribution of boron was ranged $65{\sim}155{\mu}g/L$ in March, $26{\sim}125{\mu}g/L$ in June, $22{\sim}140{\mu}g/L$ in September and $50{\sim}162{\mu}g/L$ in December. The higher levels of boron were found at Kum-ho river nearby the industrial complex, which seemed to be greatly affected by domestic sewages and wastewater from the upper streams. Thus, the concentration of boron and that of other components showed strong statistical correlation in this area. In the Nak-dong River, industrial wastewater and domestic sewages is thought to be the sources of boron.

• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.822-828
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• 2007

Perchlorate is an unregulated contaminant but recently many cases of perchlorate contamination have been reported in the US. In Japan, also, a couple of contamination incidents caused by perchlorate occurred. Against this backdrop, investigation on perchlorate was urgent for Korea. Accordingly, perchlorate investigation in tap water and river water was conducted one time a week for seven consecutive weeks at major water sources of Korea including Han River, Guem River, Yeong-san River, and Nak-dong River. Perchlorate was not found at Han River, Guem River, and Yeong-san River. However, all the 4 tap water samples in Nak-dong River recorded high level of perchlorate. Among others, NT1 located at Daegu posted the highest value of $22.3{\mu}g/L$. This level is lower than $24.5{\mu}g/L$, the threshold recommended by US EPA. Still, perchlorate contamination in drinking water can deal a heavy blow to nerve development of infants and children by causing iodine deficiency. At the 1st and 2nd investigations, perchlorate concentration reached $18.7{\sim}95.6{\mu}g/L$ and $4.0{\sim}25.6{\mu}g/L$ respectively, both of which are relatively higher. The high perchlorate concentration in Nak-dong River was possible because of the waste water discharged from LCD manufacturing factory which was located at NS3 in Gumi, Korea. Perchlorate concentration of waste water from the factory was $730{\sim}1,858{\mu}g/L$.

• Analytical Science and Technology
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• v.17 no.5
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• pp.423-433
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• 2004

This study was examined occurrence of bisphenol A (BPA) and nonylphenol (NP) in waterworks system of Seoul, Korea from September 2002 to December 2003. The levels of BPA and NP in Han-river and its tributaries were as followed: Paldang-dam, ND(not detected)${\sim}0.033{\mu}g/L$ and $ND{\sim}0.823{\mu}g/L$; Kyungahn-creek, $ND{\sim}0.659{\mu}g/L$ and $ND{\sim}3.827{\mu}g/L$; Whangsuk-creek, $ND{\sim}0.528{\mu}g/L$ and $ND{\sim}12.724{\mu}g/L$, respectively. In water of 6 intake-station, the contents of NP and BPA were detected $0.122{\sim}2.724{\mu}g/L$, and $ND{\sim}0.260{\mu}g/L$, respectively. In the finished- and tap-water of three drinking water treatment plants (DWTPs) around Whangsuk-creek, BPA was not detected in all samples, while NP was in ppt levels in whole. Through the process of DWTP, also, the removal ratio of NP was above 80% in all this. Therefore, this result was suggested that levels of BPA and NP in waterworks system depended on non-point contaminants and swage treatment plants in the Han-river shed.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.57-63
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• 2004

Primary productivity of phytoplankton was measured by $^{14}C$ method from January to October of 1996 in Seonakdong River. This river was a highly productive freshwater showing the euphotic depth of 1.4 m in August and 2.1 m in the remaining season. Chlorophyll-a concentrations of phytoplankton ranged from 67 ${\mu}g\;L^{-1}$ to 894 ${\mu}g\;L^{-1}$ and showed the great increase in August. Maximum specific productivity was 2.1 ${\sim}$4.3 mg C mg $chl-a{-1}\;hr^{-1}$ and occurred above 0.4m depth. In photosynthesis-irradiance relation, photoinhibition or photosynthetic suppression of phytoplankton occurred clearly in the cold seasons, while phytoplankton (mainly Microcystis aeruginosa and its relatives) in August did not show any symptom of the photosynthetic inhibition against the high irradiance. The specific productivity of phytoplankton was eventually dependant upon incident irradiance to show the linear correlation with received irradiance infield, and the areal productivity of phytoplankton upon chlorophyll-a standing crops. In the downstream of the Nakdong River, phytoplankton productions have linearly increased since the estuarine barrage construction to reflect the gradual eutrophication in the estuarine area. Average chlorophyll-a increase of 10 ${\mu}g\;chl-a\;L{-1}$ absolutely corresponded to the primary production acceleration of 30 mg C $m^{-2}\;day^{-1}$ on the annual basis.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.776-781
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• 2006

Perchlorate ion($ClO_4^-$), which is present in the solid propellant for rocket, herbicide and some fertilizers. Perchlorate inhibits iodide uptake by the human thyroid gland. Impairment of thyroid function in expectant mothers may impact the fetus and result in effects including cerebral palsy, give rise to thyroid gland cancer. The US EPA(Environmental Protection Agency) adopted a reference dose(RfD) for perchlorate 0.0007 mg/kg-day, and this guidance lead to a Drinking Water Equivalent Level(DWEL) of 24.5 ${\mu}g/L$. The studies about perchlorate are actively performed in foreign countries, especially in USA but there is no study which surveyed the perchlorate contamination in Korea. Therefore, this study was done to investigate perchlorate contamination in Nak-dong river and tap water. The perchlorate was detected in Nakdong river and ranged from ND to 278.4 ${\mu}g/L$. The highest concentration was observed in Kumichon. The perchlorate concentration was decreased with the down stream of Nakdong river. The perchlorate concentration in tap water was varied with the cities and the concentration levels were $ND{\sim}34.1$ ppb. The highest perchlorate concentration was observed in DalsuGoo in Daegu and the similar concentration($9{\sim}11$ ${\mu}g/L$) was detected in most of the districts in Busan. The result of this study suggests that there is a perchlorate source near the Nakdong river and the urgent policy is needed to control perchlorate for the cities which are supplied from Nakdong river as for their tap water.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1332-1339
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• 2005

The purpose of this study is to the distributive property of organic pollutants in effluents of domestic sewage treatment plants around Youngsan River using simultaneous analysis method of 310 chemicals. The numerous organic pollutants were detected in five sampling sites, and the major chemicals were pesticides, CH type chemicals such as benzenes and polycyclic compounds, ande CHO type chemicals such as phenols and phthalates. About 14 pesticides were detected in the effluent and most of them were found in summer. 1-Chlorobenzen and p-octylphenol were frequently detected in the concentration range of $0.52{\sim}0.61\;{\mu}g/L$ and $0.04{\sim}0.89\;{\mu}g/L$, respectively. Moreover, 18 kinds of endocrine disrupters include diethylphthalate were detected in effluents. From the results of this study, therefore, we confirmed that the pesticides, CH and CHO type chemicals in domestic effluents throughout Youngsan River are required specific regulation.

• Journal of the Korean association of regional geographers
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• v.9 no.4
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• pp.437-460
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• 2003

It is recorded that the orignal Nam-Suk Bridge is constructed at the first year of Oh-Bong(B.C. 57). But I believe that it can be back to the 19 year of Jin-Hung King(AD. 558) by discovered bibliographies. The Nam-Suk Bridge is improved and remodelled from past to the late of Zosun dynasty by the development of walled city of Chongju. By the late of Gojong Empire, the Nam-Suk Bridge has stone post and monument of Nam-Suk Bridge. Because the alternations of Mu-Sim River channel, heavy floods, extension of built, up area and Japanese unconcern, the stone post and monument of Nam-Suk Bridge is lost approximately by 1910s and Nam-Suk Bridge is completely buried by the early 1930s. The Mu-Sim Hiver has negative aspects from past to the Japanese rule but has increasingly the positive aspects after the liberation of Korea. We must reconstruct these buried cultural resources to highlight the cultural identity of Chongju City.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.35-46
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• 2009

In order to investigate spatial and temporal distributional characteristics of major water qualities in the Saemangeum area during the Saemangeum dike construction, salinity, COD, dissolved nutrients(DIN, Silicate) and heavy metals were analyzed from the surface water collected in April, May, August and November 2002. The overall value of Salinity, COD, DIN, and silicate in surface waters were in the range of $13.08{\sim}31.96\;psu$, $0.12{\sim}3.43\;mg/L$, $0.001{\sim}2.638\;mg/L$, and $0.010{\sim}3.181\;mg/L$, respectively. The COD and DIN in each survey showed the highest concentration at the mouth of Mangyeong river estuary(St. 1) where freshwater flow into the Saemangeum area. The concentrations of nutrients were high in the inner part of the Saemangeum dike with low-salinity, and low nutrients in the outer part of the dike with high-salinity, which strongly indicated that concentrations were adjusted by physical mixing. The ranges of dissolved metals and acid-soluble Hg in surface seawater were $0.006{\sim}0.115{\mu}g/L$ for Co, $0.26{\sim}0.114{\mu}g/L$ for Ni, $0.14{\sim}0.93{\mu}g/L$ for Cu, $0.04{\sim}0.53{\mu}g/L$ for Zn, $0.010{\sim}0.043{\mu}g/L$ for Cd, $0.010{\sim}0.795{\mu}g/L$ for Pb, and $0.25{\sim}4.16{\mu}g/L$ for Hg. The highest concentrations of some metals except for Cd were found at the estuary(Sts. 1 or 3). In most cases, a decreasing order of metal concentrations towards open sea(low-salinity$\rightarrow$high-salinity) was observed and showed positive relationship with DIN and silicate caused by land base pollutants input. On the other hand, due to Cd desorption from suspended solids in saline water, dissolved Cd concentrations were high in high-salinity area and low in low-salinity. In November, Co, Zn, Cu and Pb were relatively high in the northern area of the outer-side of Saemangeum, which was only influenced by the Geum river discharge. The concentrations of most dissolved metals of this study were lower than those of the past data in this area, but higher than those in Lena river estuary under the pristine environment.