• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.204-209
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• 2015

The effluent limit of nickel from electroplating wastewater has been strengthened from 5 mg/L to 3 mg/L from 2014. However, currently applied treatment process for nickel plating wastewater is unable to meet the effluent limit, most of the treatment concept conducted by treatment plant is dilution with other metal bearing wastewater. This can cause very significant impact to the environment of nickel contamination. With this connection, the feasibility test has been conducted with the use of electrolysis by using sacrificial electrodes. Experiments were conducted in synthetic and electroless nickel plating wastewater. Optimal condition of current density, pH were derived from the synthetic wastewater. It was found that the removal efficiency of nickel exceeded 94% at the operation condition of at pH 9 and the current density of $1{\sim}2mA/cm^2$. At this conditions, the iron sludge was generated very low amount. However, it was unsuccessful to meet the effluent limit by applying these treatment conditions to the real electroplating wastewater. This can be explained due to the matrix effect of other metals and anions contained real electroplating wastewater. From the result of further study, the optimal conditions for the real wastewater treatment were found out to be at pH 9, current density $6{\sim}7mA/cm^2$, for 5 minutes of operating time. At these conditions, 88% removal of nickel was achieved, which results the residual nickel concentration was below 3 mg/L.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.2
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• pp.78-90
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• 2016

This report is to introduce detail processes during the restoration/revision project for the Korean Standard Methods for Marine Environment. The processes are composed of 3 steps: questionaries, QA/QC confirming step by CRM(Certified Reference Materials), and advisory council by specialists. The questionaries required four main topics to be included to the restoration/revision protocol: 1. the guidelines to sampling, transportation, storage, and pre-analytical procedures for the marine specimens, 2. the unified analytical method, especially for the organic compounds, 3. the QA/QC test requirement for CRM, 4. introduction of diverse analytical instruments, 5. the customer- friendly express of the protocol. Based on these new protocol, we expect two most important effects: 1, increased insurance of international credibility and equivalence by the QA/QC procedures, 2. increased conformability and representatively from wide-spread use of the protocol. Finally we suggested several residual topics remained to the inter-government cooperation.

• Journal of Soil and Groundwater Environment
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• v.12 no.1
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• pp.1-35
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• 2007

In the last decades, the decrease in biological or chemical availability of sorbed contaminants as contact time passed, is generally accepted. This phenomenon so called as "aging" or "sequestration" is known to directly affect risk of the contaminats. This was observed for mainly for hydrophobic organic contaminants (HOCs), but also reported for heavy metals. Aging is known to be directly related to sorption-desorption hysteresis, irreversible sorption, desorption-resistance, nonequilibrium sorption, etc. The decrease in bioavailability due to aging or sequestration indicates realistic decrease in risk potential. Recently a risk-based management concept by scientific evidences but not the simple measurement of contaminant concentration has been attempted to determine environmentally acceptable remedial endpoint. This is because selection of remedial endpoint based on not total concentration but the bioavailability and toxicity of contaminants can reduce both the treatment cost and remedial activities of the contaminated sites. The bioavailability and toxicity of the residual contaminants are highly affected by the fate and transport and also directly affect the exposure pathways and bioaccumulation of contaminants in the living biota. In this paper, scientific feasibility on the risk-based clean-up and management of contaminated sites is reviewed.

• Korean Journal of Environmental Agriculture
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• v.5 no.1
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• pp.30-34
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• 1986

This study was carried out to determine the heavy metal contents in sluges of Keumho river and her branches. The heavy metal contents of sludge are the highest in Sincheon, Kongdancheon and Dalseocheon among the branches. The large part of heavy metal exists in $0{\sim}5cm$ from sludge surface. The sequential extraction with various reagents showed that the residual and organically bound fraction were the most abundant pool. Decomposition of organic matter caused sludge to release heavy metals. On the extraction of sludge with various solution having different pH, it was found that the lower the pH, the more heavy metal was extracted. However, considerable amount of heavy metal was not extracted even with pH 3 solution.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.962-969
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• 1999

Elastic and elasto-plastic stress analyses of AlN/Cu and AlN/W pints produced by active-metal brazing method using Ag-Cu-Ti insert-metal were performed with use of Finite-Element-Method(FEM). The results of stress analyses were compared with those from the pint strength tests and the observations of fracture behaviors. It was shown that a remarkably larger maximum principal stress is built in the AlN/Cu pint compared to the A1N/ W joint. Especially, the stress concentration with tensile component was confirmed at the free surface close to the bonded interface of AlN/Cu. The elasto-plastic analysis under consideration of stress relaxation effect of Ag-Cu-Ti insert possessing a so-called 'soft-metal effect' showed that the insert leads to a lowering of maximum principal stress in AlNiCu pint, even though an increase of the insert thickness above 100$\mu\textrm{m}$ could not bring its further decrease. The maximum pint strengths measured by shear test were 52 and 108 MPa for AlNiCu and AlN/W pints. respectively. Typical fractures of AlN/Cu pints occurred in a form of 'dome' which initiated from the free surface of AlN close to the bonded interface and proceeded towards the AlN inside forming a large angle. AlN/W pints were usually fractured at AlN side along the interface of AlN/insert-metal.

• Journal of Navigation and Port Research
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• v.41 no.4
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• pp.195-206
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• 2017

In situ capping technology for marine sediment pollution control has never been applied in South Korea. In this study a pilot project for the capping was carried out in Busan N Harbor. Pipeline and clamshell capping technologies were implemented for the pollution control. Changes of capping shapes, sediment contamination, and the time and costs required for the two constructions were compared. Both the pipeline and clamshell technologies were found to satisfy the target thickness of 50 cm on average. However, the pipeline method did not operate sensitively in terms of change of the sea floor topography, resulting in an uneven shape and a thickness. Organic carbon and ignition loss quite decreased after the pipeline or the clamshell capping while pH showed no significant change. Organic and residual fraction of Cd, Ni, and Zn in the sediments appeared to decrease after all cappings. The pipeline method took a construction time four times as much as the clamshell method. The clamshell method was demonstrated to reduce the construction cost by about 40% compared with the pipeline method. However, a monitoring for all the parameters needs to be conducted at least two years in order to better evaluate an efficiency of the pollution control by these capping constructions.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.239-247
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• 2008

Objective of this study was to investigate residual the levels of heavy metals in rice grain and soils of "Top-Rice" and common rice cultivation areas from 2005 to 2007. Soil and rice grain samples were taken from 33 "Top-rice" areas and neighboring paddies, and analyzed for the elements using ICP-OES and ICP-TOF-MS after acid digestion. A concentration of arsenic in paddy soil was 1.33 mg/kg which was below 1/5-1/11 fold of the threshold levels(concern: 4 mg/kg, action: 10 mg/kg), and paddy soil was 0.06 mg/kg of Cd(cadmium) being below 1/25-1/67 fold of the limits(concern: 1.5 mg/kg, action: 4 mg/kg). A level of Cu(copper) in paddy soil was 4.57 mg/kg which was below 1/11-1/27 fold of the threshold levels(concern: 50 mg/kg, action: 125 mg/kg), and Pb(lead) concentration in paddy soil was found to be a 4.68 mg/kg. In addition, Hg(mercury) concentration in paddy soil was to be a 0.03 mg/kg, which was below 1/131-1/328 fold of the threshold levels(concern: 4 mg/kg, action: 10 mg/kg). The average concentrations of As, Cd, Cu, Pb and Hg in the polished rice samples were 0.037, 0.043, 0.280, 0.048 and 0.002 mg/kg, respectively. These levels are lower than those of other countries in rice grains. Assuming the rice consumption of 205.7 g/day by total dietary supplements in Korea, the amount of total weekly metal intake of As, Cd, Cu, Pb and Hg by polished rice were estimated to be 0.0892, 1.035, 6.712, 1.161 and 0.054 ${\mu}g/kg$ body weigh/week, respectively. The PTWI(%) of As, Cd, Cu, Pb and Hg were 5.95(inorganic arsenic), 0.26(total arsenic), 14.79, 0.19, 4.65 and 1.07% estimated to be 0.0892, 1.035, 6.712, 1.161 and 0.054 ${\mu}g/kg$ body weigh/week, respectively. In conclusion, it was appeared that the heavy metals contamination in the brown and polished rice should not be worried in Korea.

• Journal of Food Hygiene and Safety
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• v.21 no.4
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• pp.231-237
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• 2006

Nowadays the teabag is worldwide used for various products including green tea, tea, coffee, etc. since it is convenient for use. In case of outer packaging printed, however, there is a possibility that the plasticizers which is used for improvement in adhesiveness of printing ink may shift to inner tea bag. In this study, in order to monitor residual levels of plasticizers in teabags, we have established the simultaneous analysis method of 9 phthalates and 7 adipates plasticizers using gas chromatography (GC). These compounds were also confirmed using gas chromatography-mass spectrometry (GC-MSD). The recoveries of plasticizers analyzed by GC ranged from 82.7% to 104.6% with coefficient of variation of $0.6\sim2.7%$ and the correlation coefficients of each plasticizer was $0.9991\sim0.9999$. Therefore this simultaneous analysis method was showed excellent reproducibility and linearity. And limit of detection (LOD) and limit of quantitation (LOQ) on individual plasticizer were $0.1\sim3.5\;ppm\;and\;0.3\sim11.5\;ppm$ respectively. When 143 commercial products of teabag were monitored, no plasticizers analysed were detected in filter of teabag products. The migration into $95^{\circ}C$ water as food was also examined and the 16 plasticizers are not detected. In addition we carried out analysis of heavy metals, lead (Pb), cadmium (Cd), arsenic (As) and aluminum (Al) in teabag filters using ICP/AES. $Trace\sim23{\mu}g$ Pb per teabag and $0.6\sim1718{\mu}g$ Al per teabag were detected in materials of samples and Cd and As are detected less than LOQ (0.05 ppm). The migration levels of Pb and Al from teabag filter to $95^{\circ}C$ water were upto $11.5{\mu}g\;and\;20.8{\mu}g$ per teabag, respectively and Cd and As were not detected in exudate water of all samples. Collectively, these results suggest that there is no safety concern from using teabag filter.

• Journal of Food Hygiene and Safety
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• v.25 no.1
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• pp.24-29
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• 2010

This study was conducted to estimate the contents of heavy metals including lead, cadmium, arsenic and total mercury in alcoholic beverages in Korea. Concentration of Hg was analyzed by gold amalgamation method, using mercury analyzer, while concentration of Pb, Cd and As was analyzed by ICP-MS. Concentration (${\mu}g/kg$) of heavy metal in fermented liquors were; for Pb $9.9\;{\pm}\;8.4$(0~38.0), Cd $5.8\;{\pm}\;4.9$(0~5.4), As $28.6\;{\pm}\;19.4$(1~96.4), Hg $0.7\;{\pm}\;1.2$(0~10.6). Concentration (${\mu}g/kg$) of distilled liquors were ; for Pb $4.4\;{\pm}\;5.7$(0~29.3), Cd $2.0\;{\pm}\;2.5$(0~10.3), As $12.0\;{\pm}\;17.0$(0~95.6), Hg $0.2\;{\pm}\;0.3$(0~2.3). Concentration(${\mu}g/kg$ of other liquous were ; for Pb $7.5\;{\pm}\;5.1$(0~13.7), Cd $5.8\;{\pm}\;3.9$(0.6~11.2), As $25.2\;{\pm}\;39.0$(0.5~103.3), Hg $0.3\;{\pm}\;0.1$(0.1~0.5). The present study showed that difference of the amount of constituent in a same category of food are not affect to the content of heavy metals among them. The residual levels of takju, yakju, sake, beer, fruit wine, soju, whiskey, brandy, general distilled liquor, liquor, other liquors are within the maximum levels, prescribed by Korea food code. It is given that heavy metal exposure of Pb, Cd, As, Hg from consumption of alcoholic beverages (takju, yakju, sake, beer, fruit wine, soju, whiskey, brandy, general distilled liquor, liquor, other liquors) are less than 0.03%, 0.06%, 0.01%, 0.01% (mean) in provisional tolerable weekly intake (PTWI) respectively, indicated by FAO/WHO.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.2
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• pp.76-90
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• 2018

To determine the distribution of mercury (Hg) in the coastal surface sediments around the Korean peninsula, the baseline concentration of Hg was estimated, the extent of contamination was assessed, and the factors controlling the distribution were discussed. The concentrations of Hg in surface sediments were significantly high in Jinhae-Masan Bay in the South Sea, Ulsan-Onsan Bay and Yeongil Bay in the East Sea, but Hg in other sediments showed a similar distribution to Cs and relatively very low concentration between 0.21 and $39.5{\mu}g/kg$ ($13.6{\pm}7.80{\mu}g/kg$). Compared to the sediment quality guidelines in Korea, 8 % of the surface sediments (n=282) analyzed in this study exceeded the values of the threshold effects level (TEL), and six sediments collected around Onsan Port were higher than the value of the probable effects level (PEL). The contamination levels of Hg were assessed by the enrichment factors using the baseline concentration (2.06Cs+1.75) based on the residual analysis from the linear regression line for Cs, and further, factors controlling the distribution of Hg were discussed by the comparison with geochemical substances depending upon the Hg enrichment level. Hg concentrations were correlated well with Cs concentration in the range of less than 1.69 of EF implying grain size control, while in the range of 1.69 and 4.03 Hg concentrations were correlated well with Fe oxyhyroxide and organic carbon contents, which indicates Hg was enriched by superior sorption capability. On the meanwhile, samples with higher EFs (4.03 to 74.9) showed fairly positive correlations with other metals (Cu, Zn, Pb) rather than geochemical substances. For samples in Youngil Bay and Ulsan-Onsan Bay (n=30), Hg concentrations were correlated only with other metals rather than geochemical substances implying simultaneous supply of metal particles from metal refineries. But samples at Gosung, Sokcho and Uljin coast were correlated well with organic carbon even though they had high EFs. In addition, samples in Jinhae-Masan Bay with high contents of S were enriched by relatively high sulfide formation.