• Journal of Korean Neurosurgical Society
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• v.62 no.4
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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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• 2003.11a
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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.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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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.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.308-314
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• 2012

In order to monitor the residual pesticides in environment friendly agricultural commodities, fruits and fruiting vegetables. Twenty-five agricultural commodities were collected twice in May and August 2011 from nine environment friendly agricultural commodities-selling supermarkets and retail stores located in eight major cities in Korea. The number of each agricultural commodity collected, 555 samples in total, was 152 organic agricultural products, 202 pesticide-free agricultural products and 201 low-pesticide agricultural products. Pesticide residues in samples were analyzed by multiresidue method for 245 pesticides using a GC-ECD/NPD and an HPLC-DAD/FLD and the peaks suspected as pesticides were identified with a GC/MSD. As a result of pesticide residue analysis, three pesticides, bifenthrin, EPN and chlorpyrifos, were detected from four samples including apple, representing a detection rate of 0.72%. The residue levels of the four pesticide-detected samples were less than their maximum residue limits (MRLs) but one pesticide EPN detected from pear exceeded its legible criterion of one twentieth MRL. Estimated daily intakes of the pesticides detected from fruits and fruiting vegetables were less than 0.76% of their maximum permissible intake.

• Nuclear Engineering and Technology
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• v.3 no.1
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• pp.9-13
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• 1971

The levels of strontium-90 in milk produced in Korea were determined during the past six years. Milk samples were collected from dairies and market shops in seoul area. Strontium-90 in milk was separated from calcium using fuming nitric acid and purified radiochemically. After seculear equilibrium was completed, the radioactivity of yttrium-90 was counted in a low background beta counting system. The determination of stable calcium in milk was also made by volu-metric method using 0. 1 N potassium permanganate solution. The highest value of 34.9 pCi $^{90}$ Sr/g-Ca was determined in August, 1966 and the lowest value was 7.5 pCi $^{90}$ Sr/g-Ca in August, 1967. From the result we can say that levels of strontium-90 are decreasing year after year and are far bellow the maximum permissible level recommended by International Committe on Radiation Protection.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.6
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• pp.753-758
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• 2007

To assess the safety of solar salts of Jeollanamdo province where most of Korean solar salts are produced, 433 samples of solar salts in total were collected and analyzed for their contents of sodium chloride and heavy metals (lead, cadmium, arsenic and mercury). Sodium chloride contents ranged from 80 to 85% in 63% of solar salts analyzed. Lead was not detected in 77% of solar salt samples and showed a value of below the maximum permissible limit (2 ppm) in other samples. Cadmium was not detected in most samples (78%), and the other samples where cadmium was detected showed a value far below the maximum permissible limit (0.5 ppm) except for three ones. Arsenic was detected in only four samples, but their concentrations were far below the permissible limit (0.1 ppm). Mercury was not detected in all samples. There were some differences between producing areas in the levels of sodium chloride and lead of solar salts, but the contents of cadmium, arsenic and mercury did not show significant regional differences. These results clearly indicate that solar salts produced from Jeollanamdo province are safe in the aspects of lead, cadmium, arsenic and mercury contents.

• Earthquakes and Structures
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• v.23 no.1
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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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• v.6 no.4
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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.

• Journal of Environmental Science International
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• v.19 no.6
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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.