• 한국물환경학회지
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• 제18권2호
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• pp.151-157
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• 2002

Landfill leachate is one of highly contaminated and heterogeneous wastewater. The leachate from initial landfill can be treated by anaerobic process because it contains biodegradable matters, particularly, volatile fatty acids (VFAs). However, the anaerobic treatment of leachate is generally required longer hydraulic retention time (HRT) than aerobic process and another treatment process to satisfy effluent concentration. Therefore the modification of conventional anaerobic treatment is needed. Two phase anaerobic membrane process (TPAMP) is an integrated membrane process to be able to separate anaerobic metabolism into two phase which are acidogenesis and methanogenesis for improvement of anaerobic treatment efficiency. In this study, the efficiency of TPAMP and conventional anaerobic treatment were compared in terms of HRT, effluent SCOD, VFAs Membrane used in TPAMP was the UF of capillary type with the surface area of $0.048m^2$. The average effluent SCOD of conventional anaerobic treatment was 1352 mg/L and the removal was 96 % at HRT 60 days, while in TPAMP, 927 mg/L and 98% at HRT 30 days.

• Parasites, Hosts and Diseases
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• 제51권1호
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• pp.139-142
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• 2013

Pinworm infection can occur through contact with contaminated surfaces followed by ingestion or even through inhalation of infective eggs. We have limited information regarding environmental contamination by eggs of Enterobius vermicularis. In order to determine environmental risk factors associated with the rate of E. vermicularis infection, we investigated possible environmental risk factors using a questionnaire from 46 kindergartens in 3 different cities of the southeast area of Korea. In total, using the cellotape anal swab technique, 3,422 children were examined for E. vermicularis infection. We evaluated E. vermicularis egg of books, educational materials, toys, room door handles, dusts of window edges, desks, chairs, tables, and dusts of classrooms. The overall egg-positive rate for E. vermicularis was 6.0%, and the prevalence of enterobiasis in each kindergarten ranged between 0% and 16.9%. We found that 78.9% of egg positive kindergartens were managed by private foundations, which was significantly higher, compared with kindergartens managed by public foundations or the nation. Compared with public or national kindergartens, most private kindergartens were located in residential areas and the number of children in these areas was significantly higher. In conclusion, numbers of children in kindergartens was found to be an environmental risk factor associated with transmission of enterobiasis in Korea.

• Advances in environmental research
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• 제3권3호
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• pp.207-216
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• 2014

A study was conducted to determine the phytotoxic effect of mercury on seed germination and seedling growth of an important arid legume tree Albizia lebbeck. The seeds germination and seedling growth performance of A. lebbeck responded differently to mercuric chloride treatment (1 mM, 3 mM, 5 mM and 7 mM) as compared to control. Seed germination of A. lebbeck was significantly (p < 0.05) affected by mercury treatment at 1 mM. Root growth of A. lebbeck was not significantly affected by mercury treatment at 1 mM, and 3 mM. Shoot and root length of A. lebbeck were significantly (p < 0.05) affected by 5 mM concentration of mercury treatment. Increase in concentration of mercury treatment at 5 mM and 7 mM significantly (p < 0.05) reduced seedling dry weight of A. lebbeck. The treatment of mercury at 1 mM decreased high percentage of seed germination (22%), seedling length (10%), root length (21.85%) and seedling dry weight (9%). Highest decrease in seed germination (51%), seedling (34%), root length (48%) and seedling dry weight (41%) of A. lebbeck occurred at 7 mM mercury treatment. A. lebbeck showed high percentage of tolerance (78.14%) to mercury at 1 mM. However, 7 mM concentration of mercury produced lowest percentage of tolerance (51.65%) in A. lebbeck. The seed germination potential and seedling vigor index (SVI) clearly decreased with the higher level of mercury. Plantation of A. lebbeck in mercury-polluted area will help in reducing the burden of mercury pollution. A. lebbeck can serve better in coordinating in land management programs in metal contaminated areas. The identification of the toxic concentration of metals and tolerance indices of A. lebbeck would also be helpful for the establishment of air quality standard.

• 대한조선학회논문집
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• 제31권1호
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• pp.94-101
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• 1994

해상에 누출된 기름의 거동은 크게 초기확산, 수평이동 그리고 풍화과정으로 나눌 수 있다. 본 논문에서는 초기확산과 수평이동을 고려하는 단기예측모델을 개발하여 경기만에 적용하였다. 누출된 기름의 초기확산과정에서는 Fay의 3단계 분류법에 근거한 경험식으로 확산반경을 추정하고, 수평이동과정에서는 바람과 $M_2$조석을 고려하여 기름의 이동을 추정 하였다. 조석 수치모델을 위해서 깊이방향으로 적분된 운동방정식을 사용하였고, 수치 계산을 위해 교차 격자체계를 채택하였다. 시간전개를 하는 방법으로 양해법과 중간시간전개법을 이용하여 그 계산결과를 서로 비교하였다. 수치해의 정확도를 검증하기 위하여 간단한 직사각형 유체영역에 먼저 수치모델을 적용한 다음, 실제 계산영역인 경기만에 적용하였다. 또한, 사고 발생시간과 누출장소, 누출된 양과 누출 지속시간, 바람의 크기와 방향을 입력하면 기름의 이동방향과 오염지역 그리고 해안선의 오염정도를 가시화할 수 있는 기능을 단기 예측모델에 포함 시켰다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권2_spc호
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• pp.86-100
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• 2020

Analyzing and monitoring environmental contaminants based on geophysical exploration techniques have become important and it is now widely applied to delineate spatial distribution geophysical characteristics in wide area. Among the techniques, induced polarization (IP) method, which measures polarization effects on electrical potential distribution, has drawn much attention as an effective tool for environmental monitoring since IP is sensitive to changes in biochemical reactions. However, various reactions stemming from the presence of multiple contaminants have greatly enhanced heterogeneity of polluted sites to result in highly variable electrical characteristics of the site. Those contaminants influence chemical and physical state of soil and groundwater to alter electrical double layer, which in turn influences polarization of the media. Since biochemical reactions between microbes and contaminants result in various IP effects, IP laboratory experiments were conducted to investigate IP responses of the contaminated soil samples under various conditions. Field IP surveys can delineate the spatial distribution of contamination, while providing additional information about electrical properties of a target medium, together with DC resistivity. Reviewing IP effects of contaminants as well as IP surveys can serve as a good starting point for the application of IP survey in site assessment for environmental remediation.

• 한국토양비료학회지
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• 제48권5호
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• pp.391-396
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• 2015

Arsenic (As) contamination of agricultural soils resulting from mining activity has caused major concern due to the potential health risk. Therefore the current study was carried out to investigate the relationship between fractionation of As in soil and rice uptake and to provide a basic information for adequate management of As contaminated agricultural soil. Twenty agricultural soils and rice affected by the abandoned mining sites were collected. Soil chemical properties and As concentrations (total and sequential extracted) in soils were determined and As concentrations in polished rice were analyzed. The average concentration of As in non-specifically adsorbed (F1), specifically adsorbed (F2), amorphous hydrous oxides of Fe and Al (F3), crystalline hydrous oxides of Fe and Al (F4) and residual phase (F5) were 0.08, 1.38, 10.34, 3.26 and $10.98mgkg^{-1}$, respectively. Both soil pH and available phosphorus were positively correlated with the concentrations of As in F1 and F2. These results indicate that increasing the soil pH and available phosphorus can significantly increase the easily mobile fractions of As (F1 and F2). The average concentration of As in polished rice was $0.09mgkg^{-1}$. The concentrations of As in F1 and F2 showed a positive correlation with the concentrations of As in polished rice. Therefore soil pH and available phosphorus affect the distribution of As fractionation in soils and thus affect As bioavailability.

• 한국환경과학회지
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• 제27권11호
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• pp.947-956
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• 2018

Trains have been a major means of transport in Korea during these past decades. However, train facilities such as stations and repair shops are contaminated with organic and inorganic substances. There is a high probability of train facility contamination with polyaromatic hydrocarbons (PAHs). This study evaluated the PAH and heavy metal contamination of soil near railroads in the Kyungpook area. A total of 18 soil samples were collected from the railroads and analyzed for 16 PAHs and 6 heavy metal species. The contamination level of the top soil was found to be slightly higher than that of the subsoil for contamination with PAHs. The ratio of carcinogenic PAH concentration to the total PAH concentration was relatively high, with a maximum of 0.9. The toxicity equivalent (TEQ) of the PAHs were 500.6 ng/kg in the topsoil and 355.5 ng/kg in the subsoil. The ratio of low molecular PAHs (LPAHs) to high molecular PAHs (LPAHs) ranged from 6.7 to 29.5; this shows that contamination is primarily due to combustion of fuel rather than due to petroleum. The ratio of phenanthrene to anthracene and the ratio of fluoranthene to pyrene also show that contamination occurred due to combustion for transportation. The heavy metal contamination level was lower than the Korean standard, but higher than the background concentration; this indicates that the soil was affected by the operation of the railways.

• 공업화학
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• 제30권3호
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• pp.345-351
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• 2019

본 연구에서는 $TiO_2$를 기반으로 한 중공사형 흡착제를 제조와 다양한 금속산화물 첨가에 따른 비소 흡착 특성을 평가하였다. 실험 결과 $TiO_2$ 중공사형 흡착제가 가장 우수한 비소 흡착 성능을 보였으며, 금속산화물을 첨가한 경우 금속산화물이 $TiO_2$ 표면의 산점을 막음으로 인해 오히려 비소 흡착 성능이 저하되었다. 그러나 장시간 비소 흡착 성능을 비교한 결과 $Al_2O_3$를 첨가한 중공사형 흡착제의 비소 흡착 성능이 증진되었다. 또한 비표면적 및 기공 크기가 상대적으로 클수록 비소 흡착 성능이 우수하였으며, 루이스 산점과 브뢴스테드 산점이 풍부하게 존재할수록 흡착에 유리한 사이트가 제공됨을 확인하였다. 이를 통해 기존 파우더 형태의 상용 $TiO_2$를 담체 형태로도 제조하여 소규모 정수처리 시설에 적용이 가능할 것으로 판단된다.

• 실내환경 및 냄새 학회지
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• 제17권4호
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• pp.330-336
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• 2018

The objective of this study was to determine whether crops and fruits absorb the naturally occurring asbestos (NOA). The concentration of asbestos in various crops and fruits grown in NOA areas was analyzed and background levels of asbestos in ambient air and soil samples were assessed. Actinolite/Tremolite asbestos were detected in all soil samples. Among 21 ambient air samples, 2 samples were recorded to contain 0.0005 f/cc (fiber per cubic centimeter) but no asbestos was detected in the other samples using transmission electron microscopy (TEM). However, no evidence suggesting that the crops and fruits could be contaminated by NOA was found in this study. The excess lifetime cancer risks (ELCRs) of ABS scenarios (agricultural activities) used in this study were calculated by using the Arithmetic (AM) and Geometric mean (GM) of ELCRs. The AM and GM of ELCRs estimated from digging soil and weeding activities did not exceed $1{\times}10^{-4}$, which was defined as the general acceptable risk range for exposure. The results of this study would be informative to NOA managers and related policy makers to make plans to prevent unexpected exposure to asbestos to residents living in an NOA area.

• 자원환경지질
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• 제55권2호
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• pp.127-135
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• 2022

Excessive presence of As level in groundwater is a major health problem worldwide. In the Red River Delta in Vietnam, several million residents possess a high risk of chronic As poisoning. The As releases into groundwater caused by natural process through microbially-driven reductive dissolution of Fe (III) oxides. It has been extracted by Red River residents using private tube wells for drinking and daily purposes because of their unawareness of the contamination. This long-term consumption of As-contaminated groundwater could lead to various health problems. Therefore, a predictive model would be useful to expose contamination risks of the wells in the Red River Delta Vietnam area. This study used four machine learning algorithms to predict the As probability of study sites in Red River Delta, Vietnam. The GBM was the best performing model with the accuracy, precision, sensitivity, and specificity of 98.7%, 100%, 95.2%, and 100%, respectively. In addition, it resulted the highest AUC of 92% and 96% for the PRC and ROC curves, with Eh and Fe as the most important variables. The partial dependence plot of As concentration on the model parameters showed that the probability of high level of As is related to the low number of wells' depth, Eh, and SO₄, along with high PO₄^3- and NH₄⁺. This condition triggers the reductive dissolution of iron phases, thus releasing As into groundwater.