• Journal of Environmental Science International
• /
• v.27 no.11
• /
• pp.947-956
• /
• 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.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.1217-1224
• /
• 2010

These days, the maintenance of closed waste landfill come to the fore social problem such as legal maintenance period, after closed maintenance deposits, stability evaluation guides and environmental survey for closed landfill management. Therefore the many non-sanitary closed waste landfill has been removed by selection and transfer to sanitary landfill and incineration. When the remove the non-sanitary landfill, the pollution level of bottom soil was investigated by related government law. In this case study, the soil contamination survey was performed to evaluate the pollution level of non-sanitary closed landfill bottom soil. Based on this study, the pollution level of studied non-sanitary landfill bottom soil was content with related government law for third area(factory, parking lot, gas station, road, railroad use etc.).

• Food Science of Animal Resources
• /
• v.32 no.3
• /
• pp.376-378
• /
• 2012

Aflatoxin M1, ingested as aflatoxin B1 via contaminated feedstuff and later converted into, is a major problematic target for milk safety control among the aflatoxin class. Korean government has controlled level of AFM1 in milk at 500 ppt as maximum residue level (MRL), and more recently, government also publicized the proposal for more strict control on fungal toxins about infant and baby foods. In this study the levels of Aflatoxin M1 (AFM1) of 42 marketed milk samples were determined with Enzyme-Linked Immunosorbent Assay (ELISA) to evaluate the status on the contamination of Aflatoxin M1. The evaluated ELISA performances of limit of detection (LOD) and the half maximal inhibitory concentration ($IC_{50}$) were 5 pg/mL (ppt) and 49 ppt, respectively. In all 42 samples, AFM1 appeared above the 5 ppt, with the average of 21 ppt and the range of up to 90 ppt. Only 3 (7%) of samples showed the level of contamination above the EU MRL (50 ppt). Although there was incidence of higher level of contamination compared with previous reports, the result of this study requires more intensive study to control of AFM1 in milk and infant foods.

• Tribology and Lubricants
• /
• v.17 no.6
• /
• pp.482-489
• /
• 2001

Changes in light transmission characteristics caused by various types of oil contaminations were experimentally measured with a built-in type wear monitoring device. Three kinds of iron powders of different size distribution, carbon duct, two kinds of solutions and grease were used for the test contaminants in this work. Light intensity of the transmitted light was measured with the contamination level. Results showed that the transmitted light intensity decreased linearly with the contamination concentration in the oil and the slope was affected by the size distribution. Light attenuation was also caused greatly by carbon dust, water contamination and poly-meric fibers in terms of the light absorption. As a result, it was proved that the optical measurement device could be applicable effectively for detecting any significant change in lubricating oils.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.06a
• /
• pp.287-298
• /
• 2001

Change in light transmission characteristics caused by various types of oil contaminations was experimentally measured with a built-in type wear monitoring device. Three kinds of iron powders of different size distribution, carbon dust, two kinds of solutions and grease were used for the lest contaminants in this work. Light intensity of the transmitted light was treasured with the contamination level. Results showed that the transmitted light intensity decreased linearly with the contamination concentration in the oil and the slope was affected by the size distribution. Light attenuation was also caused greatly by carbon dust, water contamination and polymeric fibers mainly due to the light absorption. As a result, it was proved that the optical measurement device could be applicable effectively for detecting any significant change iii lubricating oils.

• Ecology and Resilient Infrastructure
• /
• v.2 no.3
• /
• pp.237-246
• /
• 2015

Heavy metal pollution in soil, such as lead contamination, has become an area of interest in Korea because of urbanization and atmospheric deposition from neighboring countries. Therefore, in this research, eco-physiological responses such as chlorophyll contents, antioxidant enzyme activity, photosynthetic rate, biomass and phytoaccumulation abilities were investigated for 4 commonly used native roadside tree species to suggest suitable tree species to cope with lead contamination. The target species, Ginkgo biloba, Prunus yedoensis, Zelkova serrata and Chionanthus retusus showed lead toxicity by significant changes of chlorophyll contents and antioxidant enzyme activities on treatments over 200 mg Pb/kg. However, biomass and photosynthetic rates only showed significant responses of plants in the highest level (5,000 mg/kg) treatment. Especially, G. biloba did not show any significant changes of antioxidant enzyme activity, photosynthetic rate, and biomass even in the highest level treatment. In low level - environmentally realistic treatments, G. biloba and P. yedoensis showed the highest phytoaccumulation rate of lead from soil. Selecting and planting species like G. biloba which have good phytoaccumulation abilities and resistance to lead contamination by further research will be required to deal with emerging lead contamination.

• Geomechanics and Engineering
• /
• v.14 no.6
• /
• pp.563-570
• /
• 2018

Ballast layer has an important role in vertical stiffness and stability of railway track. In most of the Middle East countries and some of the Asian ones, significant parts of railway lines pass through desert areas where the track (particularly ballast layer) is contaminated with sands. Despite considerable number of derailments reported in the sand contaminated tracks, there is a lack of sufficient studies on the influences of sand contamination on the ballast vertical stiffness as the main indicator of track stability. Addressing this limitation, the effects of sand contamination on the mechanical behavior of ballast were experimentally investigated. For this purpose, laboratory tests (plate load test) on ballast samples with different levels of sand contamination were carried out. The results obtained were analyzed leading to derive mathematical expressions for the strain modulus ($E_V$) as a function of the ballast level of contamination. The $E_V$ was used as an index for evaluation of the load-deformation characteristics and bearing capacity of track substructure. The critical limit of sand contamination, after which the $E_V$ of the ballast reduces drastically, was obtained. It was shown that the obtained research results improve the current track maintenance approach by providing key guides for the optimization of ballast maintenance planning (the timing of ballast cleaning or renewal).

• Biomedical Science Letters
• /
• v.23 no.4
• /
• pp.333-338
• /
• 2017

This study was performed to assess microbial contamination of Aronia melanocarpa, blueberry, raspberry, and cranberry sold in several markets. We investigated total aerobic bacteria and detected foodborne bacteria by multiplex PCR from Aronia melanocarpa, blueberry, raspberry, and cranberry. Total aerobic bacteria of each sample showed mean 3.54 log CFU/g for Aronia melanocarpa, mean 1.90 log CFU/g for blueberry, and mean 1.40 log CFU/g for raspberry, but not detected in cranberry. Specially, Aronia melanocarpa contained high total aerobic bacteria contamination among various berries and contamination level reached 4.17 log CFU/g in sample 5. To evaluate the effect of distribution conditions, we also investigated total aerobic bacteria of various berries. Total aerobic bacteria showed mean 2.89 log CFU/g for berries in refrigerated distribution and 1.40 log CFU/g in frozen distribution, but not in dry distribution. For assessment of foodborne bacteria contamination, we conducted PCR with multiplex primers of E. coli O157, S. aureus, B. cereus, V. parahaemolyticus, L. monocytogenes, Y. enterocolitica, Salmonella spp., Shigella spp. Among these foodborne bacteria, B. cereus was amplified in Aronia melanocarpa in sample 4 and blueberry in sample 1, 2, 3, and 5. The result of quantitative analysis of B. cereus contamination showed 4.08 log CFU/g of Aronia melanocarpa in sample 4 and higher contamination rate 4.07 log CFU/g of blueberry in sample 3. These results suggest that strict food safety control in harvest and distribution of various berries is necessary to prevent foodborne disease and improve microbiological safety.

• Journal of Food Hygiene and Safety
• /
• v.30 no.2
• /
• pp.159-165
• /
• 2015

The aim of this study was to investigate microbiological contamination levels in the manufacturing company of ginseng products (white and red ginseng). Firstly, the contamination level for ginseng and each stage ginseng were 1.8~4.9 log CFU/g (total bacteria), 1.2~3.0 log CFU/g (coliform), 0.8~4.1 log CFU/g (fungi). However, only Bacillus cereus among pathogenic bacteria was detected from a few sample. The contamination of total bacteria tended to decrease as ginseng was being processing. Therefore, that of finished products (white and red ginseng) showed the lowest contamination level among each stage ginseng sample. That of fungi decreased steadily, although the contamination of fungi has tended to increase right after ginseng was steamed. Secondly, the contamination level for working tools and facilities were $1.7{\sim}4.7log\;CFU/cm^2$ (total bacteria), $0.4{\sim}4.0log\;CFU/cm^2$ (coliform), $0.9{\sim}4.2log\;CFU/cm^2$ (fungi). Especially, washing and peeling machines were higher contamination level. Finally, the contamination level of worker who washed and steamed ginseng was higher than worker who shaped, sorted and stored ginseng. Also, Staphylococus aureus was detected at 0.2~0.7 log CFU/hand on some wokers' hands. These results showed proper heating condition (temperature and time) and tidy manufacturing facility are the most important to avoid developing any microbiological problem of Ginseng Products.

• Journal of Food Hygiene and Safety
• /
• v.35 no.1
• /
• pp.13-22
• /
• 2020

A total of 244 cereal samples (oat, sorghum, adlay, and proso millet) were collected from fields to examine the contamination of Fusarium mycotoxins in cereals during harvest season in 2017 and 2018. The contamination levels of deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEA) were analyzed individually by using the immunoaffinity column clean-up method with ultra performance liquid chromatography, and fumonisins (FUM) were analyzed by using the QuEChERS method with liquid chromatography-mass spectrometry. Highest level of NIV contamination (120.0-3277.0 mg/kg) was observed in oat samples among the analyzed cereals. In the adlay samples, DON contamination was the highest (maximum level 730.0 ㎍/kg). The proso millet samples had a high frequency of detection of NIV and ZEA (61.5% and 57.9%, respectively), but the levels were low (average detection level of NIV, 75.6 ㎍/kg, for ZEA, 21.5 ㎍/kg). Among the cereal samples, sorghum had the highest contamination frequency of DON, ZEA, and FUM, and the co-occurrence of Fusarium mycotoxin was 70.0%, which was higher than the average of 29.9%. In order to safely manage Fusarium mycotoxin levels in cereals, continuous research on the development of contamination prevention technologies together with monitoring of mycotoxin contamination is needed.