• Journal of Food Hygiene and Safety
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• v.30 no.4
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• pp.350-358
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• 2015

This study was designed to evaluate the sanitary characteristics of sea water in a part of the south coast, Korea and to check the seawater which is in compliance with the recommended bacteriological criteria for shellfish cultivation. The samples of sea water were collected at 14 sampling stations established in the survey area between March 2014 and October 2014. Food poisoning caused by seafood consumption is often associated with pathogenic microorganisms originated from fecal contamination. Therefore, fecal coliform is very important criteria for evaluating the safety of fisheries in coastal areas. The range of geometric mean (GM) and the estimated 90th percentile values of total coliform were 4.1~83.1 MPN/100 mL, and 11.7~834.1 MPN/100 mL, respectively. The GM and the estimated 90th percentile values of fecal coliform were 2.5~22.7 MPN/100 mL and 2.5~170.0 MPN/100 mL, respectively. Therefore, the bacteriological safety of seawater at this shellfish-growing area met with the Korean Shellfish Sanitation Program (KSSP) criteria for a growing area. However, the values are seasonally exceed the KSSP criteria, suggesting that the monitoring and evaluation of seawater quality is very important in shellfish-growing area.

• Journal of Soil and Groundwater Environment
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• v.11 no.1
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• pp.23-36
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• 2006

Experimental leaching of tailings was performed as a function of times (1, 2, 4, 7, 14, 21 and 30 days) in the laboratory using reaction solutions equilibrated to three different pH set-points (pHs 1,3 and 5). The initial pHs of 5 and 3 stabilized at either 4.6-6.1 or 2.8-3.5 in 2 days and decrease gradually with time afterwards. The results of the leaching tests indicate that the significant increase in the sulfate concentrations and in acidity after 7 days of leaching results from the oxidation of sulfide minerals. There were no significant variations in the extractable Pb found in the leach solutions of pH 5 and 3 within the reaction time (1-30 days), while Zn, Cd and Cu concentrations tend to significantly increase with time. In tailings leaching at an initial pH=1, two trends were observed: i) The 'Zn-type' (Zn, Cd and Cu), with increasing concentrations between days 1 and 30, corresponding to the expected trend when continuous dissolution is the dominant process, ii) the 'Pb-type' (Pb), with decreasing concentrations over time, suggesting rapid dissolution of a Pb source followed by the precipitation of 'anglesite' in relation to the large increase in dissolved sulfates. The high sulfate concentrations were coupled with high concentrations of released Fe, Zn and Cd. Release of Zn and Cd and acidity from these leaching experiments can potentially pose adverse impact to surface and groundwater qualities in the surrounding environment. The kinetic problems could be the important factor which leads to increasing concentrations of trace metals in the runoff water.

• Journal of Wetlands Research
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• v.15 no.2
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• pp.215-222
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• 2013

In this study, the nutrient concentration changes along the hydrologic flow path of a free water surface flow constructed wetland (CW) treating agricultural stream runoff was investigated. Dry sampling was performed from April 2009 to November 2011 at five locations representing each treatment units of the CW. Grab water samples were analyzed for nitrogen forms such as total nitrogen (TN), total Kjeldahl nitrogen, nitrate, and ammonium; and phosphorus forms including total phosphorus (TP) and phosphate. Findings revealed that the physical properties such as temperature, dissolved oxygen and pH affected the TP retention in the CW. High nutrient reduction was observed after passing the first sedimentation zone indicating the importance of settling process in the retention of nutrients. However, it was until the 85% of the length of the CW where nutrient retention was greatest indicating the deposition of nutrients at the alternating shallow and deep marshes. TN and TP concentration seemed to increase at the final sedimentation zone (FSZ) suggesting a possible nutrient source in this segment of the CW. It was therefore recommended to reduce or possibly remove the FSZ in the CW for an optimum performance, smaller spatial allocation and lesser construction expenses for similar systems.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.456-460
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• 1998

This research was attempted to prove suppressing effect of medicinal plants on the intestinal absorption of toxic heavy metals. In vitro study was performed by membrane filtration considering intestinal absorption conditions. From drinking water contaminated singly with 10 and 50 times level of water quality standard for heavy metals, the removal ratio of lead was $40{\sim}60%$ by Chicorium intybus, Angelica acutiloba and Ganoderma lucidium. And the removal ratio of cadmium was $20{\sim}40%$. The removal ratio of lead contaminated with both was $30{\sim}50%$ by every sample similarly, the removal ratio of cadmium was $10{\sim}30%$. The removal ratio of Angelica acutiloba was more higher than Chicorium intybus and Ganoderma lucidium. Considering the extraction conditions of samples, $70^{\circ}C$, 2 min conditions were higher than $95^{\circ}C$, 10 min conditions, the removal ratios of heavy metals were similar. And the membrane filter permeated the material under 500 mw selectively, so the final filtrate could regard as passive transport in intestinal absorption. In conclusion, this research exhibited that the medicinal plants beverages have a suppressing effect on intestinal absorption of lead and cadmium in drinking water.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.1-9
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• 2009

Distribution characteristics of organophosphorous pesticides (OPs) were studied over the period from May to September, 2006 in Asan Bay, Korea. During the study period, 28 kinds of organophosphorous pesticides dissolved in surface water and adsorbed on suspended particle were measured. In the surface water, the dominant OPs were IBP and DDVP, and the concentration were in the ranges from not detected to 2014.4 ng/L for IBP and 3.2 to 696.3 ng/L for DDVP. The highest concentrations of OPs in the surface waters in Asan Bay appeared in July and August showing that seasonal distributions of OPs depend on application time and precipitation. The concentrations of OPs generally decreased with the increase of distance from the mouth of Asan Bay, implying progressive dilution of pesticides in the estuarine system. OPs residue in Asan Bay was relatively higher than in other area of Korea. The concentrations of the observed OPs concentrations did not exceed the seawater quality standard of Korea. DDVP, IBP, Diazinon, Phorate, Azinphos ethyl and Chlorfenvinfos had higher adsorption capacity onto suspended particle than the other OPs. In the study area, adsorption coefficients $(K_d)$ of OPs were closely related to the Log $K_ow$ of each compound.

• The Korean Journal of Pesticide Science
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• v.12 no.1
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• pp.24-33
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• 2008

In this study, the mobility of seven pesticides from soil in different slopes was investigated by simulated rainfall under field conditions. Simulated rainfall subjected to $22\;mm\;hr^{-1}$ was treated using rainfall simulator after 12 hr of pesticide treatment. Amounts of the pesticides were measured in run-off water samples. The soil samples collected before and after rainfall from upper, middle and lower parts and three different depths of sloped-plot were also analyzed. At result, the order of the amount of pesticide residues was $0{\sim}15$ > $15{\sim}30$ > $30{\sim}45\;cm$ of soil depth and no pattern was shown in upper, middle and lower, and different slopes in soil samples. all pesticides from the run-off water samples collected from soils were detected maximum 96% within 60 minutes after first collection except carbendazim and cypermethrin which have the lowest water solubilities. These results revealed that mobility of pesticides can be dependant mainly on soil textures and physicochemical properties of pesticides. Therefore, it can be suggested that selection of pesticides should be considered for properties of pesticide in the alpine and sloped-land.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.12
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• pp.861-867
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• 2011

In order to understand the extent of contamination of the sediments on the Mankyoung and Dongjin Rivers flowing into the Saemangeum Reservoir, the concentrations of ignition loss (IL), COD, total nitrogen (T-N), total phosphorus (T-P), and heavy metals (As, Cd, Cr, Pb, Zn) were measured. The average concentrations of IL, COD, and T-P were 2.40 (${\pm}2.18$)%, 2.97 (${\pm}3.06$) mg/g sediment, 0.370 (${\pm}0.351$) mg/g sediment, respectively, showing the extent of contamination is not serious. However, the concentrations of these parameters in the samples taken in year 2009 were higher than those in year 2008, indicating the contamination of sediments goes on gradually. The concentrations of T-N were in the range of 0.59~13.11 mg/g sediment with variation of locations and seasons. It was determined that the T-N contamination is serious when the concentrations were compared with the dredging guidelines of sediments in the Korean freshwaters, indicating the countermeasures are required to maintain the water quality of the Saemangeum Reservoir. The concentrations of heavy metals except chromium did not exceed the worrisome level of soil contamination stipulated by the Soil Environment Conservation Act of Korea. The high concentration of chromium to be concerned in some samples from the upstream of Mankyoung River requires source analysis and countermeasure to control the contamination.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.45-53
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• 2008

In this paper, the property of influent water and variations of removal efficiencies in each unit processes were studied based on the experiment data from the advanced water treatment plant in a city of Korea. The microbial species in the biological activated carbon(BAC) after backwashing of activated carbon filtration tank(ACFT) were also identified. The property and the removal efficiencies were evaluated by considering 8-9 items. The variations of 4 items were investigated from the influent and effluent of ACFT. SEM recording were conducted on BAC samples before and after backwashing. And the existence of attached microorganisms were identified through HPC(Heterotrophic Plate Counter) investigation. For the property of influent water, the concentrations of most items were maintained in the constant ranges, some items had seasonal properties. For the removal efficiencies, there were some items showing similar monthly-pattern and increasing with time, other items decreasing at the ozone contactor. Through these investigations, it was possible to distinguish the target items, which were removed by the advanced processes. The existence of microorganisms in ACFT could be predicted based on the variation curve of NH$_3$-N, and this fact were proved by SEM and HPC.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1944-1947
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• 2008

강우기에 하천 유역에서의 탁수 발생은 대상 지역의 토양, 토지 이용형태와 식생 분포, 강우의 강도, 토지의 경사 등에 따라 큰 영향을 받게 된다. 본 연구에는 토지의 이용형태에 따른 강우 시 탁수 발생량을 평가하고자 용담댐 유역의 탁수 발생특성 조사를 실시하였다. 2005년의 조사지점은 유역면적이 가장 작은 주자천 유역과 구량천, 금강본류를 대상으로 하였다. 구량천과 금강본류는 용담댐 유역을 구성하는 가장 큰 두 소유역이며 다를 지역에 비해 오염원이 많아 용담댐수질에 많은 영향을 주는 하천이다. 현장조사는 6월 27일부터 7월 3일 까지 실시하였다. 2007년 조사 대상 지역은 주자천 유역의 주천교 지점과 금강본류 유역의 월곡교 지점을 선정하였다. 현장조사는 6월21${\sim}$22일, 9월14${\sim}$15일 2회에 걸쳐 실시하였으며 시간별 현장 탁도 측정 및 시료 채취를 통한 분석을 병행하였다. 2005년에 실시한 조사결과 오염원이 많고 유역이 넓은 천천은 7월 1일에 유입량이 최대로 348.16CMS였으며, 그날 탁도는 오후 2시 10분조사시에 최대 2060NTU를 나타냈다. 구량천은 같은날 조사를 실시하여 유량은 최대 200.33CMS였고, 최대 탁도는 763NTU를 나타냈다. 반면 주자천에서는 최대 탁도가 98.4NTU를 나타내 가장 탁도가 높은 금강본류와는 약 13배의 차이를 나타냈다. 2007년 1차 조사는 6월 21${\sim}$22일에 걸쳐 이루어 졌다. 주천교 지점은 시간최대 강우 17mm가 발생한 시점에 최대 92NTU의 탁도를 나타내었고 그 이후 감소하여 20NTU이하의 탁도를 유지하였다. 반면, 월곡교 지점은 시간최대 23mm의 강우가 발생하였고, 최대 탁도는 3,610NTU에 도달하였으며 1,000NTU이상의 고탁도가 6시간 이상 유지된 후, 시간이 지남에 따라 점차 감소하였다. 이러한 결과는 미개발지역인 주천교 지점의 경우 강우에 의한 탁수 발생이 상대적으로 적음을 보여주고 있으며 월곡교 지점과 같이 개발로 인해 노출된 토양의 경우 강우에 의해 쉽게 침식이 일어나 고탁도의 탁수를 발생시킴을 보여준다. 그러나 주천교지점에서 2005년에 조사한 자료와 비교해 보면 2007년이 적은 강우임에도 불구하고 탁도는 높게 나타난 결과를 나타내고 있으며 이는 토지이용의 고도화에 따른 영향으로 판단되었다. 연구 결과 유역내에서 탁수 발생은 같은 강도의 강우에 있어서 큰 차이를 보이고 있음을 확인할 수 있었다. 따라서 강우기에 저수지에서의 탁수 문제의 해결을 위해서는 상류 유역의 탁수 발생원 관리가 중요함을 보여주고 있으며, 토지 이용 형태에 따른 토양 침식 방지 대책이 강우기의 댐 내 탁도 문제를 개선할 수 있는 중요한 방안으로 판단된다.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.76-85
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• 2004

Anaerobic decomposition of municipal solid waste (MSW) had potential adverse impacts such as the production of methane and long-term post closure on human health and the environment. It was demonstrated that aerobic degradation of MSW resulted in the reduction of a methane yield and the enhancement of stabilization of MSW. Excavated solid wastes were both aerobically and anaerobically treated in order to evaluate the effects of air injection on the stabilization of landfill site. The municipal solid waste (MSW) samples were excavated from a 10-year old landfill (operation period: 1991. 11~1994. 11), Jeonju, Korea. Excavated municipal solid wastes are primarily composed of soils and vinyl/plastics. For the two aerobic simulated lysimeters, the levels of $O_2$ ranged 1.6~23.1% and the levels of $CO_2$ ranged 1.5~15.1%, which confirmed the aerobic decomposition. Aeration did prevent methane formation. For the anaerobic simulated lysimeter, the $CO_2$ rose as $O_2$ was consumed and low levels of CH4 were produced. The pH levels ranged from 7.7 to 8.9 for anaerobic lysimeter and from 7.3 to 8.5 for aerobic lysimeters. As expected, aerobic treatment proved to enhance the removal of biodegradable materials in the excavated solid wastes when monitoring the concentration of BOD, COD, $NH_4-N$, and $NO_3-N$ in the leachate.