• Journal of Soil and Groundwater Environment
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• v.20 no.7
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• pp.61-69
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• 2015

This study was performed to provide fundamental data to establish the new soil pollution standards and the soil contamination management plans in a rational manner. The distribution characteristics of new soil contaminants such as barium (Ba) and chromium (Cr) in soils (n=140) were investigated in relation to land-use classification and geological features. Also, the sequential extraction test was conducted to evaluate fate and mobility of new soil contaminants. The soil samples taken from 140 sites were analyzed to survey distribution levels of selected new soil contaminants. The average concentration and range for hazardous metals (Ba, Cr) were Ba 128.946 (26.757~489.587) mg/kg, Cr 30.121 (2.579~132.783) mg/kg. Based on land use classification, the highest Ba concentration was found in factory soils, followed by dry field and park soils, while Cr concentration was highest in rice paddy soils, followed by dry field and factory soils. Within 10 geological units investigated the highest Ba and Cr concentrations were observed in the soils from Okcheon group and metamorphic rocks, respectively. The BCR (European Community Bureau of Reference) sequential extraction was conducted to identify chemical distributional existence of 2 elements of soils from each geological unit. Ba in soils is mainly assumed to exists as reducible form (such as BaSO₄, BaCO₃) and Cr in soils mainly is assumed to exist as residual form (such as Cr₂O₃, Cr_xFe_1-x(OH)₃(x < 1)).

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.363-373
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• 2013

This study investigates the dispersion and behavior of Au and heavy metals in the water system (soil, AMD and stream sediment) at the abandoned Bonjeong gold mine, based on XRD, aqua regia, sequential extraction, and physico-chemical analyses. The XRD analyses targeted quartz and kaolinite in the mine waste soil and quartz and goethite in stream sediment. The physico-chemical analyses of AMD with increasing distance from water system showed that pH increased from 3.00 to 3.19 and Eh decreased from 450 to 396 mV. The Au content in AMD ranged from 0.68 to 0.97 mg/L upstream, but was not detected downstream. The Au content of stream sediment was 13.76 to 22.85 mg/kg. Sequential extraction from stream sediment revealed 10.84% exchangeable (STEP I), 11.09% carbonates (STEP II), 25.53% Fe-Mn oxides (STEP III), 26.62% organic matter (STEP IV), and 24.61% residual (STEP V).

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.303-308
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• 2015

BACKGROUND: Recently, various rice by milling degree is sold for health and taste. To provide safe food to consumers, it is need to know the change of heavy metal contents according to milling degree of rice.METHODS AND RESULTS: This study was to investigate residual the levels of cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) as stated in the milling degree of the rice contaminated Cd and Pb from 2011 to 2012 in Chungcheongnam-do. Rice samples exceeded the maximum residue limits (MRL) of Cd and Pb were milled by five degrees (0.0, 2.45, 8.02, 10.48, 15.09%). Milled rice was digested by microwave method, and analyzed heavy metal contents using ICP-OES. Recovery ratios of 4 heavy metals such as Cd, Pb, Cu and Zn were ranged for 79.7-98.9%, and limits of detection (LOD) and limits of quantitation (LOQ) were fulfilled with the normal analytical standards. Concentrations of Cd, Pb, Cu and Zn were ranged 0.416-0.433 mg/kg, 0.183-0.26 mg/kg, 3.639- 3.882 mg/kg and 16.868-19.801 mg/kg, respectively.CONCLUSION: From these results, conforming with increase of milling degree of rice, Cd, Pb, Cu, and Zn contents tended to decrease. The contents of heavy metals were decreased 3.1% in Cd, 29.3% in Pb, 6.4% in Cu and 15.1% in Zn, in according to the highest milling degree of 15.09%.

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.345-351
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• 2015

This study investigated the optimum depth for the application of bioremediation in contaminated coastal sediment using a lab scale column experiment. The biostimulants were placed in the top surface of the sediment facing seawater, 3cm, 6cm and 10cm of the depth from the surface, respectibely. During the experiment, the changes of organic pollutants and heavy metal fractions in the sediment were monitored in 1 month and 3month time intervals. The organic pollutants found during various analysis such as chemical oxygen demand, total solids and volatile solids, significantly reduced when the depth of the biostimulant was 3cm or less. In contrast, at a depth of over 6cm, the reduction of organic pollutants decreased, and the results were similar to the control. Heavy metals fractions in the sediment also changed with the depth of the biostimulants. The exchangeable fraction of the metals was quite reduced at the sediment surface in the column, but the organic bound and residual fractions considerably increased at a depth of 3cm. Based on this study, the optimum biostimulants depth for in-situ bioremediation of contaminant coastal sediment is 3cm from the sediment surface.

• Korean Journal of Metals and Materials
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• v.56 no.11
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• pp.787-795
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• 2018

The effects of tempering condition on the microstructure and mechanical properties of 30MnB5 hot stamping steel were investigated in this study. Before the tempering, hot-stamped 30MnB5 steel was composed of only ${\alpha}^{\prime}$-martensite microstructure without precipitates. After the tempering at $180^{\circ}C$ for 120 min, nano-sized ${\varepsilon}$-carbides were precipitated in the ${\alpha}^{\prime}$-martensite laths. After tempering at $250^{\circ}C$ for 60 min, cementite was precipitated along the ${\alpha}^{\prime}$-martensite lath boundaries. The cementite was also observed in the specimens tempered at $350^{\circ}C$ for 30 min and $450^{\circ}C$ for 6 min, respectively. The globular ${\alpha}$-ferrite appeared at $350^{\circ}C-30min$ tempering, and the volume fraction of ${\alpha}$-ferrite increased when the tempering temperature was increased. The yield strength increased after tempering, and it reached a peak with the tempering condition of $180^{\circ}C-120min$, due to the nano-sized precipitates in the ${\alpha}^{\prime}$-martensite lath. After the tempering, the steel's ultimate tensile strength (UTS) was decreased due to the reduction in dislocation density and C segregation to lath boundaries. The highest elongation was observed at the $180^{\circ}C-120min$ tempering condition, due to the reduction of residual stress, and the lack of precipitates along the lath boundaries. The $180^{\circ}C-120min$ tempering condition was considered to have outstanding crash performance, according to toughness and anti-intrusion calculation results. In drop tower crash tests, the 30MnB5 door impact beam tempered at $180^{\circ}C$ for 120 min showed better crash performance compared to a 22MnB5 door impact beam.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.332-339
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• 2015

The objective of this study was to evaluate the effectiveness of different biochars on the removal of heavy metals from aqueous media. The experiment was carried out in aqueous solutions containing $200mg\;CdL^{-1}$ or $200mg\;PbL^{-1}$ using two different biochars derived from soybean stover and orange peel (20 mg Cd or $Pbg^{-1}$ biochar). After shaking for 24 hours, biochars were filtered out, and Cd and Pb in the filtrate were analyzed by flame atomic absorption spectrophotometer (FAAS). In order to provide information regarding metal binding strength on biochars, sequential extraction was performed by modified SM&T (formerly BCR). The results showed that 70~100% of initially added Cd and Pb was adsorbed on biochars and removed from aqueous solution. The removal rate of Pb (95%, 100%) was higher than that of Cd (70%, 91%). In the case of Cd, orange peel derived biochar (91%) showed higher adsorption rate than soybean stover derived biochar (70%). Cd was adsorbed on the biochar mainly in exchangeable and carbonates fraction (1st phase). In contrast, Pb was adsorbed on it mainly in the form of Fe-Mn oxides and residual fraction (2nd and 4th phase). The existence of Cd and Pb as a form of surface-precipitated complex was also observed on the surfaces of biochars detected by field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectrometer (EDAX).

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.281-288
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• 2021

This study was conducted to analyze and compare the concentrations of heavy metals in 430 different products of 20 types of herbal medicines available in the domestic market in Korea by Graphite Furnace-Atomic Absorption Spectrometry (GF-AAS) and automated mercury analyzer. The accuracy for lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg) was in the range 92.67-102.56%, and the precision was 0.21-6.00 relative standard deviation (RSD%), which was in compliance with the Codex acceptable range. Furthermore, the Food Analysis Performance Assessment Scheme (FAPAS) quality control (QC) material showed a recovery range of 96.7-102.0% and 0.33-4.93 RSD%. The average contents (㎍/kg) of Pb, As, Cd, and Hg in herbal medicines were 254.9 (not detected (N.D.)-2,515.2), 171.0 (N.D.-2,465.2), 99.2 (N.D.-797.1), and 6.0 (N.D.-83.6), respectively. Based on the quantitative analysis results, the heavy metal contents of 20 types of herbal medicines distributed in Korea are within the acceptable range according to the standards issued by the Ministry of Food and Drug Safety (MFDS). By using the manufacturer of herbal products as the standard for QC, the Pb, As, Cd, and Hg contents were investigated in the packaging process just before distribution to determine the actual conditions of residual heavy metals in herbal medicines. Thus, these result may contribute to monitoring the QC of herbal medicines distributed in Korea and could provide basic data for supplying safe herbal medicines to the public.

• Korean Journal of Pharmacognosy
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• v.38 no.3 s.150
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• pp.205-216
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• 2007

South Korea is the representative consumption country of herbal medicines and most of herbal medicines circulating in Korea have been importing from the developing countries of Southeast Asia such as China, Vietnam, Indonesia and so forth. Domestic hygiene and safety are continuously proposed because herbal medicines which are circulating have the possibility could remain contaminants or residues. Physicochemical contaminants such as heavy metals, persistent organic pollutants, radionucleosides, microbial toxins, biological contaminants such as microorganisms and animals, agrochemical residues such as pesticides, substances used for fumigation, antiviral agents, and solvent residues are classified as major contaminants and residues in herbal medicines from 2005 September WHO.$^{1)}$ Currently our administration have established a permission standard and the inspection criteria against the heavy metal, the residual pesticides and a residual sulfur dioxide. Furthermore our administration is continuously monitoring and conducting researches for the policies and their scientific ground against herbal medicines. But the appearances or discoveries of the harmful new species due to environmental and industrial developments are becoming social problems. Therefore it may be necessary to continuously consider and investigate regarding hereupon. Recently, the contamination of the mycotoxins against foods such as cereals, nuts and the powdered red pepper have developed and started became problematic issue, and possibility of contamination against the herbal medicine is proposed. And since populations who are using the herbal medicines very limited to several nations, recognition and researches about contamination of mycotoxins in herbal medicines are very insufficient. Therefore it will be need to more focus on the international regulation of quality control and safety for herbal medicines. Now on, we are going to introduce the importance, occurrence, characteristic properties, World-wide research trends and detoxification of aflatoxins, which is known as the most potent mutagen, carcinogen and teratogen mycotoxins.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.189-194
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• 1998

In order to evaluate the residual effects of bituminous coal fly ash, gypsum, oyster shell as soil amendments, Chinese cabbage was cultivated on acidic sandy loam soils with low boron content. The soils were amended in the upper 15cm with amendments in previous year and the growth and qualities of plants were analyzed. Amendments treated one year before were, in metric tons per hectare, i) none(Check) ; ii) 80 fly ash(FA) ; iii) 4 shell(SH) ; iv) 56 fly ash + 24 gypsum (FG) ; v) 40 fly ash + 24 gypsum + 0.8 shell(FGS). Yield response in fresh weight of Chinese cabbage was in order of 834% for FGS > 780% for FG > 755% FA > 193% for SH plants. Reducing sugar, vitamin-C, and total nitrogen contents of leaves depending on treatments showed the same tendencies as that in yields, whereas crude fibre opposite to them. In particular, FA, FG, and FGS plants showed normal growth without both boron deficiency symptoms which appeared in Check and SH plants and possibilities of accumulation of heavy metals. In any soils treated with the above amendments, however, magnesium was insufficient.

• Journal of Sasang Constitutional Medicine
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• v.22 no.2
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• pp.93-100
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• 2010

1. Objectives: To compare the contents of hazardous substances such as crude, washing solution, crude after washing, decoction and remnant. 2. Methods: The heavy metal contents of each step were measured by inductively coupled plasma (ICP) spectrometer and mercury analyzer (MA-2). In order to analyze pesticides in Yanggyeoksanhwa-tang we used simultaneous multi- residue analysis of pesticides by GC/ECD, which was followed by GC/MSD analysis to confirm the identity of the detected pesticide in each sample. In addition, the contents of sulfur dioxide (SO2) were performed by Monier-Williams distillation method. 3. Results: 1) The mean values of heavy metal contents (mg/kg) for each steps in Yanggeoksanhwa-tang were as follows: crude (Pb; 1.87, As; 1.29, Cd; 0.28 and Hg; N.D.), washing solution (Pb; 1.98, As; 1.13, Cd; 0.10 and Hg; N.D.), crude after washing (Pb; 1.90, As; 1.40, Cd; 0.22 and Hg; N.D.), decoction (Pb; 1.90, As; 1.14, Cd; 0.11 and Hg; N.D.) and remnant (Pb; 2.39, As; 1.29, Cd; 0.25 and Hg; 0.01). 2) Contents (mg/kg) of residual pesticides in crude and decoction were not detected. 3) Contents (mg/kg) of sulfur dioxide (SO2) in crude, crude after washing and remnant exhibited 3.00, 2.00 and 2.00 mg/kg, respectively. However, contents of sulfur dioxide in washing solution and decoction were not detected. 4. Conclusions: These Results: will be used to establish a criterion of heavy metals, residual pesticides and sulfur dioxide of each step in Yanggeoksanhwa-tang.