• Economic and Environmental Geology
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• v.53 no.4
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• pp.347-362
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• 2020

Iron (hydro)oxides in aqueous environments are primarily formed due to mining activities, and they are known to be typical colloidal particles disturbing surrounding environments. Among them, hematites are widespread in surface environments, and their behavior is controlled by diverse factors in aqueous environments. This study was conducted to elucidate the effect of environmental factors, such as ionic composition and strength, pH, and natural organic matter (NOM) on the behavior of colloidal hematite particles. In particular, two analytical methods, such as dynamic light scattering (DLS) and single-particle ICP-MS (spICP-MS), were compared to quantify and characterize the behavior of colloidal hematites. According to the variation of ionic composition and strength, the aggregation/dispersion characteristics of the hematite particles were affected as a result of the change in the thickness of the diffuse double layer as well as the total force of electrostatic repulsion and van der Walls attraction. Besides, the more dispersed the particles were, the farther away the aqueous pH was from their point of zero charge (PZC). The results indicate that the electrostatic and steric (structural) stabilization of the particles was enhanced by the functional groups of the natural organic matter, such as carboxyl and phenolic, as the NOM coated the surface of colloidal hematite particles in aqueous environments. Furthermore, such coating effects seemed to increase with decreasing molar mass of NOM. On the contrary, these stabilization (dispersion) effects of NOM were much more diminished by divalent cations such as Ca²⁺ than monovalent ones (Na⁺), and it could be attributed to the fact that the former acted as bridges much more strongly between the NOM-coated hematite particles than the latter because of the relatively larger ionic potential of the former. Consequently, it was quantitatively confirmed that the behavior of colloidal hematites in aqueous environments was significantly affected by diverse factors, such as ionic composition and strength, pH, and NOM. Among them, the NOM seemed to be the primary and dominant one controlling the behavior of hematite colloids. Meanwhile, the results of the comparative study on DLS and spICPMS suggest that the analyses combining both methods are likely to improve the effectiveness on the quantitative characterization of colloidal behavior in aqueous environments because they showed different strengths: the main advantage of the DLS method is the speed and ease of the operation, while the outstanding merit of the spICP-MS are to consider the shape of particles and the type of aggregation.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.336-344
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• 2015

BACKGROUND: This study was carried out to collect occurrence data on aluminum in 12 type agricultural products and assess dietary exposure risk to the Korean population health for aluminum concentration in agricultural products.METHODS AND RESULTS: Aluminum analysis samples were performed using microwave device and Inductively Coupled Plasma Optical Emission Spectrometer. The LOD(Limit of Detection) for aluminum was 0.851 μg/kg, while the LOQ(Limit of Quantitation) was 2.838 μg/kg and recovery was 97.6% for aluminum. The average levels of aluminum in mg/kg were 0.526 for rice, 0.546 for Korean cabbage, 1.316 for corn, 6.207 for soybean, 0.549 for sweet potato, 0.257 for potato, 6.963 for spinach, 1.213 for carrot, 0.524 for garlic, 0.950 for radish, 1.015 for leek, and 3.511 for Welsh onion. The dietary exposures of aluminum through usual intake were polished rice 89.31 μg/day, Korean cabbage 33.14 μg/day, corn 0.66 μg/day, soybean 3.72 μg/day, sweet potato 6.86 μg/day, potato 4.96 μg/day, spinach 45.96 μg/day, carrot 6.79 μg/day, garlic 2.36 μ g/day, radish 7.32 μg/day, leek 2.23 μg/day and Welsh onion 43.89 μg/day, taking 0.57%, 0.21%, 0.00%, 0.02%, 0.04%, 0.03%, 0.04%, 0.04%, 0.02%, 0.05%, 0.01% and 0.28% of PTWI(2 mg/kg b.w./week), respectively.CONCLUSION: The levels of overall dietary exposure to aluminum for Korean population through intake of agricultural product was far below the recommended JECFA level, indicating of least possibility of risk.

• Journal of Food Hygiene and Safety
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• v.31 no.4
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• pp.227-249
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• 2016

Arsenic and its compounds vary in their toxicity according to the chemical forms. Inorganic arsenic is more toxic and known as carcinogen. The provisional tolerable weekly intake (PTWI) of $15{\mu}g/kg$ b.w./week established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) has been withdrawn, while the EFSA panel suggested $BMDL_{0.1}$ $0.3{\sim}8{\mu}g/kg\;b.w./day$ for cancers of the lung, skin and bladder, as well as skin lesions. Rice, seaweed and beverages are known as food being rich in inorganic arsenic. As(III) is the major form of inorganic arsenic in rice and anaerobic paddy soils, while most of inorganic arsenic in seaweed is present as As(V). The inorganic arsenic in food was extracted with solvent such as distilled water, methanol, nitric acid and so on in heat-assisted condition or at room temperature. Arsenic speciation analysis was based on ion-exchange chromatography and high-performance liquid chromatography equipped with atomic absorption spectrometry and inductively coupled plasma mass spectrometry. However, there has been no harmonized and standardized method for inorganic arsenic analysis internationally. The inorganic arsenic exposure from food has been estimated to range of $0.13{\sim}0.7{\mu}g/kg$ bw/day for European, American and Australian, and $0.22{\sim}5{\mu}g/kg$ bw/day for Asian. The maximum level (ML) for inorganic arsenic in food has established by EU, China, Australia and New Zealand, but are under review in Korea. Until now, several studies have conducted for reduction of inorganic arsenic in food. Inorganic arsenic levels in rice and seaweed were reduced by more polishing and washing, boiling and washing, respectively. Further research for international harmonization of analytical method, monitoring and risk assessment will be needed to strengthen safety management of inorganic arsenic of foods in Korea.

• Journal of Food Hygiene and Safety
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• v.25 no.4
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• pp.402-409
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• 2010

The study was conducted to estimate the contents of heavy metal in commercial herbal medicines (1047 samples of 132 species) which were collected from markets in Seoul and to analyze the contents of heavy metals of herbal medicines by classifying them by parts. The samples were digested using microwave method. The contents of heavy metal (Pb, Cd, and As) and Hg were determined using Inductively coupled plasma-Mass spectrometer (ICP/MS). And the contents of Hg were obtained by Mercury analyzer. The average values of heavy metal in herbal medicines were as follows [mean (minimum-maximum), mg/kg]; Pb 0.870 (ND-69.200), As 0.148 (ND-2.965), Cd 0.092 (ND-2.010), and Hg 0.007 (ND-0.B7). And the average values of heavy metal by parts in herbal medicines were as follows [mean (minimum-maximum), mg/kg]; Ramulus 2.046 (0.065-4.474), Herba 1.886 (0.048-10.404), Flos 1.874 (0.052-5.393), Cortex 1.377 (0.011-4.837), Radix 1.165 (0.012-70.111), Rhizoma 1.116 (0.016-5.490, Fructus 0.838 (0.017-4.527), Perithecium 0.729 (0.013-4.953), Semen 0.646 (0.006-4.416). The average values of heavy metal of imported herbal medicines except Radix were higher than domestic ones. By decoction of herbal medicines exceeding the tolerances, average intake rates of Pb, As, Cd and Hg were obtained as 6.1%, 40.3%, 4.7%, and 2.2%, respectively.

• Food Science and Preservation
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• v.24 no.8
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• pp.1094-1102
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• 2017

Hazardous metals leaching experiment was carried out in accordance with various usage environments for camping cooking utensils distributed in the market. There was a significant difference in the degree of migration for lead, arsenic, cadmium and nickel defending on the solvent and how to use, although they were all appropriate for criteria. In general, the migrated amount of aluminum was increased in acidic condition, and the migrated amount of arsenic was increased in salty condition. Physical scratches increased the overall release of hazardous metals from the portable pots and pans for camping in all solvents. Especially, in 0.5% citric acid solution, cadmium was migrated by physical scratch in stainless steel and hard aluminum pots and pans. The longer the leaching time, the higher the migration of aluminum in acid condition and arsenic in basic condition. From these results, it is desirable to use the cooking utensil for camping without being exposed to strong acidic or basic solution and scratches in order to reduce the migration of hazardous metals from them.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.369-376
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• 2008

The aim of this study was to compare the compositions and cytotoxicity of white ProRoot MTA (white mineral trioxide aggregate) and 3 kinds of Portland cements. The elements, simple oxides and phase compositions of white MTA (WMTA), gray Portland cement (GPC), white Portland cement (WPC) and fast setting cement (FSC) were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD). Agar diffusion test was carried out to evaluate the cytotoxicity of WMTA and 3 kinds of Portland cements. The results showed that WMTA and WPC contained far less magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) than GPC and FSC. FSC contained far more aluminum oxide ($Al_2O_3$) than WMTA, GPC, and WPC. WMTA, GPC, WPC and FSC were composed of main phases. such as tricalcicium silicate ($3CaO{\cdot}SiO_2$), dicalcium silicate ($2CaO{\cdot}SiO_2$), tricalcium aluminate ($3CaO{\cdot}Al_2O_3$), and tetracalcium aluminoferrite ($4CaO{\cdot}Al_2O_3{\cdot}Fe_2O_3$). The significance of the differences in cellular response between WMTA, GPC, WPC and FSC was statistically analyzed by Kruskal-Wallis Exact test with Bonferroni' s correction. The result showed no statistically significant difference (p > 0.05). WMTA, GPC, WPC and FSC showed similar compositions. However there were notable differences in the content of minor elements. such as aluminum (Al), magnesium, iron, manganese, and zinc. These differences might influence the physical properties of cements.

• Analytical Science and Technology
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• v.29 no.4
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• pp.170-178
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• 2016

Accuracy and precision of ID methods for different spike isotopes of ⁷⁶Se, ⁷⁷Se, and ⁷⁸Se were compared for the analysis of Selenium using quadrupole ICP/MS equipped with Octopole reaction cell. From the analysis of Se inorganic standard solution, all of three spikes showed less than 1 % error and 1 % RSD for both short-term (a day) and long-term (several months) periods. They showed similar results with each other and ⁷⁸Se showed was a bit better than ⁷⁶Se and ⁷⁷Se. However, different spikes showed different results when NIST SRM 1568a and SRM 2967 were analyzed because of the several interferences on the m/z measured and calculated. Interferences due to the generation of SeH from ORC was considered as well as As and Br in matrix. The results showed similar accuracy and precisions against SRM 1568a, which has a simple background matrix, for all three spikes and the recovery rate was about 80% with steadiness. The %RSD was a bit higher than inorganic standard (1.8 %, 8.6 %, and 6.3 % for ⁷⁸Se, ⁷⁶Se and ⁷⁷Se, respectively) but low enough to conclude that this experiment is reliable. However, mussel tissue has a complex matrix showed inaccurate results in case of ⁷⁸Se isotope spike (over 100 % RSD). ⁷⁶Se and ⁷⁷Se showd relatively good results of around 98.6 % and 104.2 % recovery rate. The errors were less than 5 % but the precision was a bit higher value of 15 % RSD. This clearly shows that Br interferences are so large that a simple mathematical calibration is not enough for a complex-matrixed sample. In conclusion, all three spikes show similar results when matrix is simple. However, ⁷⁸Se should be avoided when large amount of Br exists in matrix. Either ⁷⁶Se or ⁷⁷Se would provide accurate results.

• Journal of Food Hygiene and Safety
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• v.37 no.5
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• pp.323-327
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• 2022

The mineral content of Tricholoma matsutake was evaluated for comparison of mineral contents according to the area of cultivation. Ten domestic and thirty Chinese (10 Yanji, 10 Yunnan and 10 Tibet) T. matsutake specimens were assessed using an atomic absorption spectrophotometer (AAS) and inductively coupled plasma mass spectrometer (ICP-MS). The Na, Mg, K, and Ca contents of domestic T. matsutake were 128.12±85.25 mg/kg, 218.52±105.35 mg/kg, 7,534.58±2,691.52 mg/kg, and 17.69±7.14 mg/kg, respectively, while those of Yanji T. matsutake were 124.89±57.24 mg/kg, 64.07±27.52 mg/kg, 1,439.18±311.04 mg/kg, and 10.88±4.52 mg/kg, respectively. The Na, Mg, K, and Ca contents of Yunnan T. matsutake were 90.78±23.23 mg/kg, 77.40±28.36 mg/kg, 1,446.29±126.33 mg/kg, and 28.42±5.18 mg/kg respectively, while those of Tibet T. matsutake were 143.50±41.54 mg/kg, 124.64±50.18 mg/kg, 3,530.95±2,714.99 mg/kg, and 21.05±8.71 mg/kg, respectively. The Cu contents of domestic, Yanji, Yunnan, and Tibet T. matsutake were 105.43±32.97 mg/kg, 19.92±8.95 mg/kg, 54.51±16.91 mg/kg, and 64.80±23.01 mg/kg, respectively. Both domestic and Chinese T. matsutake samples showed significantly different K, Mg, and Cu levels in this study. Therefore, a comparative evaluation of the K, Mg, and Cu contents of multiple domestic and Chinese T. matsutake varieties is needed to determine the appropriate area of cultivation in the future.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.3
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• pp.175-182
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• 2022

Heavy metals can be intentionally or unintentionally introduced into plastic food utensils, containers, and packaging (PFUCP) as additives or contaminants, which can be ingested with food by humans. Here, seven-heavy metals (lead, cadmium, nickel, chromium, antimony, copper, and manganese) with toxicity concerns were selected, and risk assessment was done by establishing their migration from 137 PFUCP products made of 16 materials distributed in Korea. Migration of heavy metals was examined by applying 4% acetic acid as a food simulant (70℃, 30 minutes) to the PFUCP products. Inductively coupled plasma mass spectrometry (ICP-MS) was employed for the analysis of migrated heavy metals, and the reliability of quantitative results was confirmed by checking linearity, LOD, LOQ, recovery, precision, and expanded uncertainty. As a result of monitoring, heavy metals were detected at a level of non-detection to 8.76 ± 11.87 ㎍/L and most of the heavy metals investigated were only detected at trace amounts of less than 1 ㎍/L on average. However, antimony migrated from PET products was significantly higher than other groups. Risk assessment revealed that all the heavy metals investigated were safe with a margin of exposure above 311. Collectively, we demonstrated that heavy metals migrated from PFUCP products distributed in Korea appear to be within the safe range.

• Analytical Science and Technology
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• v.22 no.4
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• pp.336-344
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• 2009

This survey was carried out to estimate the contents of heavy metals (Hg, Pb, Cd, and As) in 10 kinds of dried marine products (n=189) which are closely related to food resources. The contents of heavy metals were estimated by inductively coupled plasma spectrometer (ICP) and mercury analyzer. The values of heavy metals in dried marine products were as follows (Mean${\pm}$SD (range), mg/kg). The average contents of heavy metals in the dried marine products were Hg $0.058{\pm}0.069$ (0.002~0.502) mg/kg, Pb $0.178{\pm}0.598$ (ND~5.130) mg/kg, Cd $0.306{\pm}0.610$ (ND~6.802) mg/kg, As $5.282{\pm}6.158$ (ND~71.760) mg/kg. The range of heavy metal contents in dried marine products are low level, except of lead contents (n=2). In the comparison of heavy metal content by anchovy size, it was shown that cadmium, mercury and arsenic were meaningfully different. The contents of heavy metals by the shape of shrimp and Alaska Pollack were shown that the result of each group was meaningless. In the comparison imported production with domestic production, in the case of common squid, cadmium and arsenic were meaningfully different. The weekly average intakes of Hg, Pb and Cd from dried marine products takes about 1.17~11.52% of PTWI (Provisional Tolerable Weekly Intakes) that FAO/WHO Joint Food Additive and Contaminants Committee has set to evaluate their safeties.