• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.689-697
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• 2006

Distribution and speciation of arsenic in water resources was investigated in the Ulsan mine area. In 62% of uoundwater samples from the mine area, total As concentrations exceeded 0.05 mg/l, the Korean Drinking Water Standard. As(V) was the major type in groundwater with minor As(III). Arsenic species appeared to be in transition stages following redox changes after exposure to the air through the monitoring wells. In areas around the mine, the mine and Cheongog spring appeared to be the sources of arsenic contamination of water resources. The spring showed 0.345 mg/1-As, as much as seven times of the Korean standard. Groundwater and stream samples showed As-concentrations greater than 0.05 mg/l in 30% and 33% samples, respectively, and 60 and 67% of samples exceeded 0.01 mg/l of WHO guideline, respectively. Again, As(V) was a dominant species, however, several samples had As(III) in appreciable levels. In one stream sample, organic species including DMA and AsB were detected in low levels, probably resulted from transformation or related biogeochemical processes.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.119-128
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• 2017

BACKGROUND: Miscellaneous cereal have been largely consumed in Korea as due to their physiological functions beneficial to human health. The cereals are currently a social concern because they have been found to contain heavy metals. Thus, monitoring heavy metals in the cereals is an important requirement for food safety analysis. In this study, we determined arsenic concentration in the cereals randomly harvested from different markets. METHODS AND RESULTS: Inorganic arsenic was determined by ICP-MS coupled with HPLC system. The HPLC-ICP-MS analysis was optimized based on the limit of detection and recover test to reach $0.13-1.24{\mu}g/kg$ and 94.3-102.1%, respectively. The concentrations of inorganic arsenic equivalent to daily exposure were levels of $19.91{\mu}g/day$ in mixed grain, $1.07{\mu}g/day$ in glutinous rice, $0.77{\mu}g/day$ in black brown rice, $0.13{\mu}g/day$ in barley and $0.11{\mu}g/day$ in soybeans. CONCLUSION: The levels of arsenic in miscellaneous cereals were found lower than the recommended The Joint FAO/WHO Expert Committee on Food Additives (JECFA) levels, suggesting that the cereals marketed in Korea are not potential concern in risk assessment.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.227-237
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• 2008

Arsenic has recently become of the most serious environmental concerns, and the worldwide regulation of arsenic fur drinking water has been reinforced. Arsenic contaminated groundwater and soil have been frequently revealed as well, and arsenic contamination and its treatment and measures have been domestically raised as one of the most important environmental issues. Arsenic behavior in geo-environment is principally affected by oxides and clay minerals, and particularly iron (oxy)hydroxides have been well known to be most effective in controlling arsenic. Among a number of iron (oxy)hydroxides, for this reason, 2-line ferrihydrite was selected in this study to investigate its effect on arsenic behavior. Adsorption of 2-line ferrihydrite was characterized and compared between As(III) and As(V) which are known to be the most ubiquitous species among arsenic forms in natural environment. Two-line ferrihydrite synthesized in the lab as the adsorbent of arsenic had $10\sim200$ nm for diameter, $247m^{2}/g$ for specific surface area, and 8.2 for pH of zero charge, and those representative properties of 2-line ferrihydrite appeared to be greatly suitable to be used as adsorbent of arsenic. The experimental results on equilibrium adsorption indicate that As(III) showed much stronger adsorption affinity onto 2-line ferrihydrite than As(V). In addition, the maximum adsorptions of As(III) and As(V) were observed at pH 7.0 and 2.0, respectively. In particular, the adsorption of As(III) did not show any difference between pH conditions, except for pH 12.2. On the contrary, the As(V) adsorption was remarkably decreased with increase in pH. The results obtained from the detailed experiments investigating pH effect on arsenic adsorption show that As(III) adsorption increased up to pH 8.0 and dramatically decreased above pH 9.2. In case of As(V), its adsorption steadily decreased with increase in pH. The reason the adsorption characteristics became totally different depending on arsenic species is attributed to the fact that chemical speciation of arsenic and surface charge of 2-line ferrihydrite are significantly affected by pH, and it is speculated that those composite phenomena cause the difference in adsorption between As(III) and As(V). From the view point of adsorption kinetics, adsorption of arsenic species onto 2-line ferrihydrite was investigated to be mostly completed within the duration of 2 hours. Among the kinetic models proposed so for, power function and elovich model were evaluated to be the most suitable ones which can simulate adsorption kinetics of two kinds of arsenic species onto 2-line ferrihydrite.

• Economic and Environmental Geology
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• v.42 no.2
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• pp.95-105
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• 2009

Systematic studies are performed for arsenic adsorption on synthesized lepidocrocite. The synthesized lepidocrocite with high surface area of $94.8\;g/m^2$ has shown that the point of zero charge(PZC) is 6.57 determined by potentiometric titration, suggestive of high capacity of arsenic removal. Results show that arsenite[As(III)] uptake by synthesized lepidocrocite is greater than that of arsenate[As(V)] at pH $2{\sim}12$, indicating that the lepidocrocite has high affinity toward arsenite rather than arsenate. Adsorption of arsenate decreases with increasing pH from 2 to 12, whereas arsenite sorption increases until pH 8.0, and then decreases dramatically with increasing pH, suggesting that changes in surface charge of the lepidocrocite as a function of pH playa important role in aresinc uptake by the lepidocrocite. Upon kinetic experiments, our results demonstrate that both arsenite and arsenate sorption on the lepidocrocite increases rapidly for the first 4 h followed by little changes during the duration of the experiment, showing that adsorption plays a key role in aresenic uptake by the lepidocrocite. Our results also show that power function and elovich models are the best fit for the adsorption kinetics of arsenite and aesenate on the lepidocrocite.

• Economic and Environmental Geology
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• v.34 no.4
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• pp.345-354
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• 2001

The effects on arsenic geochemistry of indigenous microorganisms isolated from an area contaminated with high concentration of arsenic were investigated. Arsenite exerted higher inhibitory effects on the microbes' growth than arsenate. During incubation of the microbes in an arsenate-spiked medium over 24 hours, decrease in microbial growth was observed as arsenate content increased. Arsenate of 150 mM or over apparently inhibited cell growth. However, further incubation for up to 4 days in the high arsenate concentration medium resulted in cell growth, implying that the microorganisms adjusted their biochemical functions to detoxify arsenic and maintain growth. Two types of microbes were observed during 20 hours to reduce arsenate to arsenite in solution through a detoxification mechanism. As well, decrease in the total arsenic content occurred over a 4-day incubation with the same microbes in an arsenate-spiked medium. Therefore it is suggested that microorganisms can influence arsenic speciation in natural settings and this may be applied to efficient bioremediation of arsenic-contaminated sites.

• Journal of Soil and Groundwater Environment
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• v.13 no.1
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• pp.52-59
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• 2008

Adsorption is a major process causing the accumulation of arsenic onto soil. Therefore, further understanding of the adsorption/desorption characteristics of arsenic species on soil is essential for predicting their fate and preparing appropriate remediation strategy to remove arsenic from soil. In this study, the column adsorption/desorption experiment has been performed with As(III) and As(V) on soil. Experiment with As(III) was conducted under reducing condition, whereas that with As(V) was under oxidizing condition. Most of As(III) was remained on the oxidation state during the experiment. The results showed that the adsorption/desorption rate of As(III) was higher than that of As(V). Adsorption and desorption of arsenic species were not completely reversible in the column experiment. It was also found that As(V) in the column experiment was adsorbed more rapidly on soil than in the batch experiment.

• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.201-205
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• 1998

In Korea, a small proportion of fishery products are contaminated with a considerable amount of potentially hazardous contaminants. So, there is generally a high risks to consumers. Inorganic contaminants with the greatest potential for toxicity are Sb, As, Cd, Pb, Hg, Se and the Sulfides. As appears to be much more variable than the others. This study was performed to assess the levels of the As in fisheries caught from the waters of the western coast of Korea. The samples included 26 kinds of fishes, 18 kinds of Mollusca, 3 kinds of Crustacea and 7 kinds of salted fishes. The Moisture content of molluscans was significantly higher than that of others (p<0.05). And the As contents of crustaceans were significantly higher than those of fishes, molluscans and salted fishes (p<0.05). The As content of Turban shell was 51.62 ppm, which was the highest among the samples. Also, the As contents of eel, cuttle fish and blue crab were found to be higher than in other fisheries. This variability offers a solution for the reduction of exposure to As through restricting the harvest of aquatic organism from the western coast of Korea.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.587-597
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• 2005

This review deals with arsenic chemistry and its occurrence in groundwater. Specifically, the paper gives an overview regarding chemical and physical properties of arsenic species, oxidation of As(III), geochemical processes related to the fate and transport of arsenic, arsenic leaching from soil, and mechanism of arsenic leaching from arsenic-containing minerals.

• Journal of Chest Surgery
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• v.39 no.6 s.263
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• pp.470-474
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• 2006

Background: Mediastinal lymph node metastasis is an important factor for staging and prognosis of non-small cell lung cancer (NSCLC), so accurate diagnosis is essential for treatment. Mediastinoscopy provides histopathological diagnosis of mediastinal lymphnode metastasis in NSCLC. The efficacy of mediastinoscopy was investigated. Material and Method: From Jun, 1999 to Aug, 2005, mediastinoscopic lymph node biopsy was performed to 348 patients with NSCLC. Patients characteristics, radiologic findings, mediastinoscopic results and pathologic stages were evaluated for investigation of safety and efficacy of modiastinoscopy in NSCLC. Result: There was 263 male and 85 female patients and the mean age was $62.1{\pm}8.5$ years. By radiologic study for mediastinal lymph node metastasis, 203 patients were negative and 145 patients were positive. Mean procedure time was $55.5{\pm}16.5$ minutes and biopsy was peformed at $2.2{\pm}1.0$ lymph node stations. There were only transient complications (1.7%) during the procedure, without other complication and mortality. There was 7.8% of false negative result in mediastinoscopy. Sensitivity (77.5% vs 71.9%, p=0.012), specificity (100% vs 74.4%, p=0.00), and accuracy (92.2% vs 73.6%, p=0.00) of mediastinoscopy were more superior than that of radiologic study for the diagnosis of mediastinal lymph node metastasis in NSCLC. Conclusion: Mediastinoscopy is a safe and effective modality for diagnosis of mediastinal lymph node metastasis in NSCLC.

• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.1-6
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• 2009

This study investigated arsenic speciation and risk assesment in 30 samples of hijiki purchased from local market in 10 Korean cities. The mean arsenic concentration of the hijiki samples was 45.65 mg/kg (dryness; moisture content of 91.1${\pm}$1.6%), and the major arsenic compound was arsenate [As(V)]. The concentrations of As(V) and As(III), as inorganic arsenic compounds, were detected to be 40.36 mg/kg and 0.37 mg/kg, respectively, and made up 88.6% (40.46 mg/kg) of the arsenic in the hijiki. Among the samples, the highest inorganic arsenic concentration was identified at 9.19 mg/kg (wet), and for an adult with a body weight of 60 kg was within an acceptable level as 0.7% (6.43 mg/60 kg/week) when compared with the provisional tolerable weekly intake (PTWI) (900 mg/60 kg/week), and would be considered safe with respect to health-hazardous effects.