• Journal of Korean Neurosurgical Society
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• 제62권4호
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• pp.414-421
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• 2019

Objective : To evaluate 3-dimensional magnetic resonance imaging (MRI) of Kambin's safe zone to calculate maximum cannula diameter permissible for safe percutaneous endoscopic lumbar discectomy. Methods : Fifty 3D MRIs of 19 males and 31 females (mean, 47 years) were analysed. Oblique, axial and sagittal views were used for image analysis. Three authors calculated the inscribed circle (cannula diameter) individually, within the neural (original) and bony Kambin's triangle in oblique views, disc heights on sagittal views and root to facet distances at upper and lower end plate levels on axial views and their averages were taken. Results : The mean root to facet distances at upper end plate level measured on axial sections increased from $3.42{\pm}3.01mm$ at L12 level to $4.57{\pm}2.49mm$ at L5S1 level. The mean root to facet distances at lower end plate level measured on axial sections also increased from $6.07{\pm}1.13mm$ at L12 level to $12.9{\pm}2.83mm$ at L5S1 level. Mean maximum cannula diameter permissible through the neural Kambin's triangle increased from $5.67{\pm}1.38mm$ at L12 level to $9.7{\pm}3.82mm$ at L5S1 level. The mean maximum cannula diameter permissible through the bony Kambin's triangle also increased from $4.03{\pm}1.08mm$ at L12 level to $6.11{\pm}1mm$ at L5S1 level. Only 2% of the 427 bony Kambin's triangles could accommodate a cannula diameter of 8mm. The base of the bony Kambin's triangle taken in oblique view (3D MRI) was significantly higher than the root to facet distance at lower end plate level taken in axial view. Conclusion : The largest mean diameter of endoscopic cannula passable through "bony" Kambin's triangle was distinctively smaller than the largest mean diameter of endoscopic cannula passable through "neural" Kambin's triangle at all levels. Although proximity of exiting root to the facet joint is always taken into consideration before PELD procedure, our 3D MRI based anatomical study is the first to provide actual maximum cannula dimensions permissible in this region.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.544-547
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• 2003

The objective of this study is to investigate the contamination levels and dispersion patterns of arsenic and heavy metals and to estimate the bioaccessible fraction of the metals in soil and plant samples in the vicinity of the abandoned Songcheon Au-Ag mine. Tailings, soils, plants (Chinese cabbage, red pepper, soybean, radish, sesame leaves, green onion, lettuce, potato leaves, angelica and groundsel) and waters were collected around the mine site. After appropriate preparation, all samples were analyzed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of As and heavy metals were found in tailings. Mean concentrations of As in agricultural soils were higher than the permissible level. Especially, maximum level of As in farmland soil was 513 mg/kg. The highest concentrations of As and Zn were found in Chinese cabbage (6.7 mg/kg and 359 mg/kg, respectively). Concentrations of As, Cd, and Zn in most stream waters which are used for drinking water around this mine area were higher than the permissible levels regulated in Korea. Maximum levels of As, Cd and Zn in stream waters were 0.78 mg/L, 0.19 mg/L and 5.4 mg/L, respectively. These results indicate that mine tailings can be the main contamination sources of As and heavy metals in the soil-water system in the mine area. The average of estimated bioaccessible fraction of As in farmland soils were $3.7\%$ (in simulated stomach) and $10.8\%$ (in simulated small intestine). The highest value of bioaccessible fraction of metal in farmland soils was $46.5\%$ for Cd.

• 한국대기환경학회지
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• 제29권5호
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• pp.536-544
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• 2013

Even a small amount of hazardous air pollutants could have a harmful influence upon human beings, animals and plants. Hazardous air pollutants have the properties of toxicity, canceration and organism accumulation. They include heavy metals, volatile organic compounds, polycyclic aromatic hydrocarbons, dioxin, etc. The Clean Air Conservation Act has defined specific hazardous air pollutants and designated 35 pollutants, distinguishing them from common air pollutants for special control. This study investigates the history of the controls of specific hazardous air pollutants with reference to some relevant laws and regulations in Korea. It investigates the regulations at the permission stage, such as the restrictions on installation of emission facilities, the permission and reporting of installation of emission facilities, and the regulations at the operation stage, such as maintaining permissible emission levels, installation of measuring devices, dues for emission, self-measurement and securing environmental engineers. The current regulatory management is not so satisfactory in regards to the serious effects of specific hazardous air pollutants upon the human body. An advanced new concept, like the maximum available control technology in US, the facilities management standards, which will soon take effect, will be able to lessen the emissions of fugitive hazardous air pollutants. In addition, this study discusses some possible stricter controls on the emission facilities of specific hazardous air pollutants and proposes some measures to maintain and supplement the current systems.

• 농약과학회지
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• 제16권4호
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• pp.308-314
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• 2012

국내 유통 중인 친환경농산물 중 과채류와 과실류의 잔류농약 모니터링을 통해 친환경인증 농산물의 잔류농약 실태조사 및 안전성을 평가하기 위하여 서울을 포함한 전국 8개 도시 9개 지점의 대형마트와 친환경농산물 전문판매점에서 25종의 과채류와 과실류를 555점 채취한 후 acetamiprid를 포함한 245종 농약을 대상으로 GC-ECD/NPD와 HPLC-DAD/FLD를 이용한 다성분동시분석법으로 잔류농약을 분석하였으며, 분석결과 농약으로 추정되는 peak는 GC-MSD를 이용하여 재확인하였다. 잔류농약 분석결과 555점의 시료 중 사과를 포함한 4점의 시료에서 bifenthrin, EPN 및 chlorpyrifos가 검출되었으며, 검출율은 0.72%이었다. 농약이 검출된 4점의 시료 중 잔류량은 모두 잔류허용기준(maximum residue limit, MRL) 이내였으나 EPN이 검출된 배는 잔류량이 허용수준인 MRL의 1/20을 초과하였다. 일일최대섭취허용량(maximum permissible intake, MPI) 대비 일일섭취추정량(estimated daily intake, EDI)은 0.76% 미만이었다.

• Nuclear Engineering and Technology
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• 제3권1호
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• pp.9-13
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• 1971

방사성 낙진에 의한 우리나라 식품의 오염도를 파악할 목적으로 우리나라의 우유중의 스트론튬-90의 양을 측정하였다. 스트론튬의 분석은 발연질산법에 의하였으며, 스트론튬 단위로 결과를 정리하기 위하여 칼슘의 함량도 동시에 정량하였다. 방사능의 측정은 $^{90}$ Sr＋$^{90}$ Y의 방사평형이 이루어진 후에 $^{90}$ Y의 방사능을 측정하였다. 액체 우유의 스트론튬-90의 함량이 가장 많았던 것은 1966년의 34.9 pCi$^{90}$ Sr/g.Ca이었으며, 1966년을 고비로 현저한 감소를 보여주고 있다. 분유의 스트론튬-90의 함량은 액체 우유와 같은 값을 보여 주고 있으며, 방사선 장해면에서 고려할때 안전한 함량임을 알 수 있다.

• 한국수산과학회지
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• 제42권6호
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• pp.561-568
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• 2009

We determined the contents of heavy metals in the muscle of wild and cultured fishes, collected from fish markets located in the eastern (Pohang), western (Gunsan), and southern (Tongyeong) coasts of Korea, from 2004 to 2005. As the results of monitoring the heavy metal contents in spring season, the wild fishes contained the range of Cd (0.01-0.08 mg/kg), Cr (ND-0.28 mg/kg), Cu (0.06-1.53 mg/kg), Hg (0.02-0.16 mg/kg), Mn (0.04-1.15 mg/kg), Ni (ND-0.09 mg/kg), Pb (0.03-0.41 mg/kg), and Zn (1.84-6.61 mg/kg). While for the cultured fishes, Cd (0.01-0.05 mg/kg), Cr (ND-0.17 mg/kg), Cu (0.05-0.61 mg/kg), Hg (0.02-0.13 mg/kg), Mn (0.03-0.17 mg/kg), Ni (ND-0.08 mg/kg), Pb (0.03-0.33 mg/kg), and Zn (2.06-6.20 mg/kg) were contained. In summer season, the contents of heavy metal in the muscle of the wild fishes were as follows: Cd (ND-0.11 mg/kg), Cr (0.01-0.37 mg/kg), Cu (0.21-1.31 mg/kg), Hg (0.01-0.11 mg/kg), Mn (ND-1.47 mg/kg), Ni (ND-0.26 mg/kg), Pb (0.06-0.48 mg/kg), and Zn (2.94-14.38 mg/kg). In comparison, the contents of heavy metal in the muscle of cultured fishes were Cd (ND-0.05 mg/kg), Cr (0.13-0.33 mg/kg), Cu (0.19-0.56 mg/kg), Hg (0.05-0.26 mg/kg), Mn (ND-0.14 mg/kg), Ni (ND-0.58 mg/kg), Pb (0.07-0.45 mg/kg), and Zn (2.43-7.53 mg/kg). Also the fall and the winter season, the heavy metal contents in the fishes showed almost similar with other season, however, Pb was lower and Zn was higher than both spring and summer season. The wild fishes contained the heavy metals a little more than the cultured fishes. We could not observe clear seasonal variation in the heavy metal contents of the fishes. The levels of Hg and Pb in all samples tested did not exceed the maximum permissible levels in the fishes set by the Korean Food & Drug Agency for safe human consumption.

• 한국식품영양과학회지
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• 제36권6호
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• pp.753-758
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• 2007

전남지역에서 생산된 천일염의 안전성에 대한 기초자료를 제공하기 위해 전남의 주 생산지에서 생산된 천일염 433 종을 대상으로 NaCl 함량 및 중금속(Pb, Cd, As, Hg) 함량을 조사하였다. NaCl 함량은 대부분 80%대 수준이었으며 전체의 63%의 천일염이 $80{\sim}85%$ 함량을 보여 가장 높은 분포를 나타내었다. Pb은 77%의 시료에서 검출되지 않았고 Pb이 검출된 천일염은 모두 기준치인 2 ppm 이하로 나타났다. Cd은 78%의 시료에서 검출되지 않았으며 3곳을 제외하고는 대부분 기준치 이하로 검출되었다. As는 4종의 시료에서만 검출되었는데 모두 기준치에 못 미치는 0.1 ppm 이하로 나타났고, Hg은 모든 천일염에서 검출되지 않았다. NaCl 함량과 Pb 농도는 지역별로 차이를 보였고 Cd, As, Hg은 지역간에 차이가 나타나지 않았다. 따라서 전남에서 생산된 천일염은 생산 지역 간의 다소의 차이는 있으나 중금속오염에 대하여 안전한 수준인 것으로 평가되었다.

• Earthquakes and Structures
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• 제23권1호
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• pp.23-34
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• 2022

This paper presents experimental studies on reinforced concrete moment resisting frames that have engineered cementitious composite (ECC) in plastic hinge length (PHL) of beam/column members and beam-column joints. A two-story frame structure reduced by a 1:3 scale was further tested through a shake-table (seismic simulator) using multiple levels of simulated earthquake motions. One model conformed to all the ACI-318 requirements for IMRF, whereas the second model used lower-strength concrete in the beam/column members outside PHL. The acceleration time history of the 1994 Northridge earthquake was selected and scaled to multiple levels for shake-table testing. This study reports the observed damage mechanism, lateral strength-displacement capacity curve, and the computed response parameters for each model. The tests verified that nonlinearity remained confined to beam/column ends, i.e., member joint interface. Calculated response modification factors were 11.6 and 9.6 for the code-conforming and concrete strength deficient models. Results show that the RC-ECC frame's performance in design-based and maximum considered earthquakes; without exceeding maximum permissible drift under design-base earthquake motions and not triggering any unstable mode of damage/failure under maximum considered earthquakes. This research also indicates that the introduction of ECC in PHL of the beam/column members' detailing may be relaxed for the IMRF structures.

• Advances in environmental research
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• 제6권4호
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• pp.241-254
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• 2017

This study was conducted to investigate the levels of heavy metals in twelve species of vegetables and assessment of health risk. Samples were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The ranges of Cr, Ni, Cu, As, Cd and Pb in vegetables species were 0.37-5.4, 0.03-17, 0.35-45, 0.01-2.6, 0.001-2.2, and 0.04-8.8 [mg/kg, fresh weight (fw)], respectively. The concentrations of As, Cd and Pb in most vegetable species exceeded the maximum permissible levels, indicating unsafe for human consumption. Health risks associated with the intake of these metals were evaluated in terms of estimated daily intake (EDI), and carcinogenic and non-carcinogenic risks by target hazard quotient (THQ). Total THQ of the studied metals from most of the vegetables species were higher than 1, indicated that these types of vegetables might pose health risk due to metal exposure. The target carcinogenic risk (TR) for As ranged from 0.03 to 0.48 and 0.0004 to 0.025 for Pb which were higher than the USEPA acceptable risk limit (0.000001) indicating that the inhabitants consuming these vegetables are exposed to As and Pb with a lifetime cancer risk. The findings of this study reveal the health risks associated with the consumption of heavy metals through the intake of selected vegetables in adult population of Bangladesh.

• 한국환경과학회지
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• 제19권6호
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• pp.671-680
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• 2010

The present study evaluated residential exposure to atmospheric formaldehyde and acetaldehyde according to distance from the a dyeing industry complex (DIC). This purpose was achieved by measuring concurrently the outdoor air concentrations in residences near the DIC and a certain distance away, plus the outdoor air concentrations at two industrial areas within the DIC boundary. Formaldehyde concentrations (median values of 24.3 and $22.5{mu}g/m^3$ in IS1 and IS2, respectively) were higher than acetaldehyde concentrations (median values of 7.4 and $7.3{mu}g/m^3$ in IS1 and IS2, respectively) at both sites. However, there was no significant difference in the industrial outdoor air concentrations of both formaldehyde and acetaldehyde between the two sites. In addition, the median formaldehyde concentration from the residential site near the DIC (RS1) was about 1.5 times higher than that from the residential site far away from the DIC(RS2), and the median acetaldehyde concentration from RS1 was about 1.3 times higher than that from RS2. It is noteworthy that the mean or median risk as well as these maximum risks are well above the USEPA's permissible risk level of $10^{-6}$ from environmental exposure. This suggests that appropriate management for formaldehyde and acetaldehyde is necessary in order to decrease risk of the residents of study areas, regardless of the distance from the DIC.