• 한국환경보건학회지
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• 제20권4호
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• pp.17-35
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• 1994

This study was performed to investigate and assess the heavy metal contamination of sediment in main stream and tributaries of the Han-river in the vicinity of Seoul. Sediment were sampled at eight locations of main stream and eighteen locations of tributaries in the spring, summer, and fall in 1993. Six heavy metals of Cd, Cu, Pb, Zn, Cr, and Hg, were assessed. For an assessment of heavy metal contamination in sediment, the assessment method of Hakanson was modified to estimate for Han-river, then classification method of Muller in sediment quality was applied. For an assessment of contamination in each heavy metal, Contamination factor C$_f^i$ which was defined the ratio of concentration of i heavy metal in investigated location to background concentration of i heavy metal in uncontaminated upper area was used. The sediment quality in each heavymetal was classified as follows if C$_f^i$<1, Class I for Non contamination, if 1 < C$_f^i$ < 3, Class II for Low contamination, if 3< C$_f^i$ <6, Class III for Moderate contamination, if 6< C$_f^i$ <12, Class IV for Considerable contamination, and if C$_f^i$ > 12, Class V for High contamination.(abbreviation)

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권3호
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• pp.58-63
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• 2016

The study examined the level of heavy metal contamination by dividing military rifle shooting ranges into the three areas, i.e firing, trajectory, and target. The target area was found to be contaminated at a level higher (Cu 845 mg/kg, Pb 30,487 mg/kg) than the Worrisome Level of Soil Contamination (hereinafter referred to as the “Worrisome Level”) The trajectory area was predicted to be free from contamination, but it did indicate contamination although it was pretty much lower (Cu 23 mg/kg, Pb 99 mg/kg) than Worrisome Level. This is attributed to the contamination spread when rearranging the soil of the target area during the maintenance of the shooting range. The firing area was also predicted to be free from heavy metal contamination, but the results analyzed indicated a contamination higher (Cu 201 mg/kg, Pb 2,286 mg/kg) than Worrisome Level. This is attributed to the fragments of the broken bullet scattering due to the pressure generated as the bullet leaves the muzzle. An examination of heavy metal contamination in the discharge area as well as gutters to prevent the intrusion of rain water from perimeter revealed a high level of contamination (Cu 298 mg/kg, Pb 6,497 mg/kg), which makes it necessary to take measures.

• 한국환경보건학회지
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• 제48권4호
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• pp.227-235
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• 2022

Background: Abandoned metal mines are classified as vulnerable areas with the highest level of soil contamination among risk regions. People living near abandoned metal mines are at increased risk of exposure to toxic metals. Objectives: This study aimed to evaluate the correlation between soil contamination levels in areas around abandoned metal mine and the blood lead levels of local residents. Moreover, we assess the possibility of using soil contamination levels as a predictive indicator for human exposure level. Methods: Data from the Survey of Residents around Abandoned Metal Mines (2013~2017, n=4,421) and Investigation of Soil Pollution in Abandoned Metal Mines (2000~2011) were used. A random coefficient model was conducted for estimation of the lower level (micro data) of the local resident unit and the upper level (macro data) of the abandoned metal mine unit. Through a fitted model, the variation of blood lead levels among abandoned metal mines was confirmed and the effect of the operationally defined soil contamination level was estimated. Results: Among the total variation in blood lead levels, the variation between abandoned mines was 18.6%, and the variation determined by the upper-level factors such as soil contamination and water contamination was 8.1%, which was statistically significant respectively. There was also a statistically significant difference in the least square mean of blood lead concentration according to the level of soil contamination (p=0.047, low: 2.32 ㎍/dL, middle: 2.38 ㎍/dL, high: 2.59 ㎍/dL). Conclusions: The blood lead concentration of residents living near abandoned metal mines was significantly correlated with the level of soil contamination. Therefore, in biomonitoring for vulnerable areas, operationally defined soil contamination can be used as a predictor for human exposure level to hazardous substances and discrimination of high-risk abandoned metal mines.

• 한국환경보건학회지
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• 제32권2호
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• pp.186-191
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• 2006

Metal contamination of medicinal herbs is of growing concern because of their potential adverse health effects. In this study, metal exposures were estimated and their potential health risks were preliminarily evaluated using available data including metal contamination levels and consumption estimates of herbal medicine in Korea. Consumption and contamination data of 34 medicinal herbs abundantly used in Oriental medicine in Korea were used in this study. Lead, mercury, arsenic, cadmium, cobalt, and chrome were identified as contaminants of potential health concerns. Even based on a conservative exposure scenario, i.e., consuming 5 times more herbal medicine with 95th percentile contamination levels, health risks associated with herbal medicine consumption were estimated to be minuscule. Herbal consumption was 0.3% of the provisional tolerable daily intake levels recommended by Joint Expert Committee on Food Additives (JECFA) of WHO/FAO. However, it should be noted that there are several important assumptions and uncertainties associated with this evaluation: This study was conducted for only 34 types of medicinal herbs of which consumption and metal contamination data were available. In addition, there are no reliable herbal medicine consumption data among Korean population. The pattern and amount of herbal (medicine) consumption in Korea need to be investigated in order to conduct more refined risk assessment associated with metal contamination in medicinal herbs.

• Transactions on Electrical and Electronic Materials
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• 제2권3호
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• pp.12-17
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• 2001

It is shown in the present study that during the HTS (hot temperature storage) test, the metal contamination by impure elements can be highly susceptible to the void formation, leading to the open failure of the power line in the memory device. Such a functional failure associated with the metal contamination was investigated to be dominant in the early stages of the HTS test while the formation of a stress-driven void is mainly observed in the later stages. In particular, it was found that the void formed in the contaminated metal takes on a slit-like shape which has been known to be characteristic of the stress-related voiding. The impure elements leading to the metal degradation were identified to be carbon and oxygen introduced during the metal sputtering process. The experimental works show that the device reliability was significantly improved by reducing the level of such impure elements within metal. It is shown in the present study that during the HTS (hot temperature storage) test, the metal contamination by impure elements can be highly susceptible to the void formation, leading to the open failure of the power line in the memory device. Such a functional failure associated with the metal contamination was investigated to be dominant in the early stages of the HTS test while the formation of a stress-driven void is mainly observed in the later stages. In particular, it was found that the void formed in the contaminated metal takes on a slit-like shape which has been known to be characteristic of the stress-related voiding. The impure elements leading to the metal degradation were identified to be carbon and oxygen introduced during the metal sputtering process. The experimental works show that the device reliability was significantly improved by reducing the level of such impure elements within metal.

• Environmental Analysis Health and Toxicology
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• 제31권
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• pp.6.1-6.10
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• 2016

Objectives This study examined the spatial distribution and the extent of soil contamination by heavy metals resulting from primitive, unconventional informal electronic waste recycling in the Agbogbloshie e-waste processing site (AEPS) in Ghana. Methods A total of 132 samples were collected at 100 m intervals, with a handheld global position system used in taking the location data of the soil sample points. Observing all procedural and quality assurance measures, the samples were analyzed for barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn), using X-ray fluorescence. Using environmental risk indices of contamination factor and degree of contamination ($C_{deg}$), we analyzed the individual contribution of each heavy metal contamination and the overall $C_{deg}$. We further used geostatistical techniques of spatial autocorrelation and variability to examine spatial distribution and extent of heavy metal contamination. Results Results from soil analysis showed that heavy metal concentrations were significantly higher than the Canadian Environmental Protection Agency and Dutch environmental standards. In an increasing order, Pb>Cd>Hg>Cu>Zn>Cr>Co>Ba>Ni contributed significantly to the overall $C_{deg}$. Contamination was highest in the main working areas of burning and dismantling sites, indicating the influence of recycling activities. Geostatistical analysis also revealed that heavy metal contamination spreads beyond the main working areas to residential, recreational, farming, and commercial areas. Conclusions Our results show that the studied heavy metals are ubiquitous within AEPS and the significantly high concentration of these metals reflect the contamination factor and $C_{deg}$, indicating soil contamination in AEPS with the nine heavy metals studied.

• 환경영향평가
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• 제22권5호
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• pp.481-489
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• 2013

There are U.S. troops with a force about 290,000 strong stationed all around the world, approximately 150 countries. Among the troops, USFK has performed principal part with its stationing for 50 years against the military threat of North Korea. However, as a result of an investigation made into environmental contamination of several bases which were restituted from US to ROK by the Land Partnership Plan in the process of relocation of USFK, it was found that the area was contaminated by not only TPH and BTEX caused by diesel fuel and JP-8 but also various heavy metal over the standard level according to the operations of corps. Among these bases, 4 corps, each of which has different duties and function, were chosen to be analyzed for the characteristics and degrees of soil contamination. Fisrt of all, in armored camp the soil was contaminated by TPH and heavy metal (Zn, Ni, Pb) due to the repairing activities of tracked vehicles and shooting exercises. In army aviation camp, the soil was contaminated by TPH, BTEX and heavy metal (Zn, Cd) due to repairing activities of aircrafts. Also, in engineer camp there was contaminated area polluted by TPH and heavy metal (Zn, Pb) caused by open-air storage of various construction materials and TPH, BTEX and heavy metal (Zn, Pb, Cu) contamination of aircraft shooting area in shooting range camp were detected. Managing environment will be more effective when we identify the contaminative characteristics and take necessary measures in advance.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.289-292
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• 2003

Laboratory tests were performed to investigate the dielectric property of saturated sands contaminated by heavy metals solution at low frequency. Differences of contamination and the real part of dielectric constant depend on heavy metal concentration was measured at low frequency, 100KHz below. The optimal frequency to develop the detection potentials of monitoring was 1KHz, 10KHz, 100KHz. At this frequency, Heavy metal contamination of saturated sands contamination can be recommended by analysis of complex dielectric constant.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.21-22
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• 2005

A study on the wear characteristics of the white metal(Sn-base alloy) bearing as a function of particle contamination level was conducted in order to establish control criteria of the lubricant in the 2-stroke marine diesel engine. Particle contamination level of the lubricants ranged from NAS 10 to 12 for the experiments. Bar-on-plate type wear test was performed using reciprocating wear tester. Based on this study it was found that there was no noticeable difference in weight loss of the white metal for NAS10 and NAS11(particle contamination level). Surface roughness of the white metal bearing after the wear test of 8hrs for the highly contaminated lubricant(NAS12 level) was up to $6{\mu}m$ in Rmax whilst that of the less contaminated lubricants(NAS10 & 11) was less than $1.5{\mu}m$ in Rmax.

• 한국진공학회지
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• 제6권1호
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• pp.1-8
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• 1997

SUS 316 합금의 노출 조건에 따른 오염 과정과 구조를 x-ray photoelectron spectroscopy실험을 통해 보았다. SUS표면에 부착된 오염 물질은 주로 metal-oxide, metal-H-oxide, CO, COH, 그리고 CxHy임을 보았다. 오염 물질의 층별 형성 구조는 $C_xH_y$/CO(COH)/metal-H-oxide/metal-oxide가 SUS합금 위에 있는 형태이다. 오염 과정은 주로 금속 구성물의 산화와 $C_xH_y$의 흡착과정 두 가지에 의해서 이루어지는 것을 볼 수 있 었다. 초고진공 환경에서는, 오염은 주로 산화층 형성에 의한 것으로 노출 시간이 증가함에 따라 산화층의 두께가 계속 증가하였다. 고진공 또는 높은 압력 환경에서는 노출 초기에 대 부분의 산화층이 형성되고, 노출 시간의 증가에 대해서는 주로 $C_xH_y$에 의한 오염이 계속 증 가하였다. 스테인레스 표면 안에 깊이 분포하고 있는 metal-oxide의 농도는 지수형으로 감 소하는 형태의 분포를 가지며 그 두께는 대기 노출된 시료의 경우 광전자의 평균자유행로 규모로 형성되는 것을 보았고, 특히 Fe-oside가 Cr-oxide를 덮고 있는 표면 편석 현상이 보 였다.