• Journal of Korean Society of Environmental Engineers
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• v.34 no.2
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• pp.109-118
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• 2012

This study achieves results from 22 maternity breast milk samples in total to demonstrate exposure level and risk assessment of PBDEs in Seoul area. PBDEs were detected in all the breast milk samples of the present study, indicating that general population in these Seoul area are widely exposed to these chemicals. Residue levels of total PBDEs (sum PBDEs from tri- to hepta-BDE) ranged of 0.84~13.1 ng/g lipid with an arithmetic mean and median of 3.56 ng/g lipid and 2.6 ng/g lipid, respectively. Global comparison shows that the levels of total PBDEs were relatively similar to those of China, Taiwan and European country (Sweden), and somewhat higher than those in some Asian (Vietnam, Philippines, and Indonesia). In the present study, however, the levels of total PBDEs in human milk are still one to two orders of magnitude lower than those in North America. Contribution rate of each congener appeared to be predominant with BDE-47, followed by BDE-153, BDE-100, BDE-99, BDE-154 and BDE-183. The sum of BDE-47 and BDE-153 accounted for more than 65% of total PBDEs in most samples. From the result of the human risk assessment of infants for total PBDEs and BDE-47 by breast milk feeding, we could find out that the average daily doses and hazard index (95th percentile) were 16.5 ng/kg bw/day and $1.2{\times}10^{-1}$ each other when nursing for 6 months after infants born. However, it was concluded that the infant health hardly had adverse seriously effects under this research condition.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.17-28
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• 2018

In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon material. Comparison study was also conducted by production of activated carbon from coconut shell (CCNS), Pinus, and Avicel, and each activated carbon was characterized by chemical composition, Raman spectroscopy, SEM analysis, and BET analysis. The amount of solid residue after thermogravimetric analysis of biomass samples at the final temperature of $750^{\circ}C$ was SAL > CCNS > Pinus > Avicel, which was the same as the order of activated carbon yields after catalytic activation. Specifically, SAL-derived activated carbon showed the highest value of carbon content (91.0%) and $I_d/I_g$ peak ratio (4.2), indicating that amorphous large aromatic structure layer was formed with high carbon fixation. In addition, the largest changes was observed in SAL with the maximum BET specific surface area and pore volume of $2341m^2/g$ and $1.270cm^3/g$, respectively. Furthermore, the adsorption test for three kinds of organic pollutants (phenol, 2,4-Dichlorophenoxyacetic acid, and carbofuran) were conducted, and an excellent adsorption capacity more than 90 mg/g for all activated carbon was determined using 100 ppm of the standard solution. Therefore, SAL, a condensed structure, can be used not only as a nanoporous carbon material with high specific surface area but also as a biosorbent applied to a carbon filter for remediation of organic pollutants in future.

• Resources Recycling
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• v.31 no.1
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• pp.65-77
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• 2022

A study was conducted in Korea on the leaching behavior and possibility of recovery of vanadium and other valuable metals from domestic vanadium titanomagnetite (VTM) by direct acid leaching. In this study, a VTM concentrate containing 0.8% V₂O₅ was used, and the ratio of magnetite to ilmenite was calculated as 1.9:1 by using the HSC program. The leaching behavior of vanadium from the VTM was similar to that of iron, and it was affected by the concentration of sulfuric acid and temperature. Further, titanium could be leached in the form of TiOSO₄ at a temperature higher than 75℃. To improve the leaching efficiency of V, Fe, and Ti in VTM, reductive sulfuric acid and oxidative sulfuric acid leaching were performed. When Na₂SO₃ was used as a reducing agent, the leaching rate of vanadium was 80% of that in that case of leaching by sulfuric acid. Similarly, the leaching rate of titanium increased from 20% to 50%. When Na₂S₂O₈ was used as an oxidation agent, most of the vanadium was leached, and the main residue found by XRD analysis was ilmenite. In studies on the possibility of recovering valuable metals, the selective extraction of metals is hardly achieved by solvent extraction from oxidation leaching solutions; however, in this study, Cyanex 923, a solvation extractant from reductive leaching solutions, could selectively extract Ti.

• Journal of Food Hygiene and Safety
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• v.38 no.2
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• pp.46-54
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• 2023

In this study, we examined the residual amounts of formaldehyde in hygiene products to determine the safety of these products in Gyeonggi-do. Formaldehyde is among the harmful substances that may remain within certain hygiene products. On the basis of an analysis of formaldehyde in a total of 222 items (6 disposable paper straws, 9 disposable paper napkins, 21 toilet papers, 13 disposable dishcloths, 16 disposable paper towels, 32 wet wipes for food service restaurants, 25 disposable cotton swabs, and 100 disposable diapers), we detected traces in three wet wipes for food service restaurants (1.87 to 4.45 mg/kg), which is approximately 9% to 22% of the standard level (20 mg/kg). We established that all the hygiene products assessed in the study met the individual standards for formaldehyde, thereby confirming that safe products are being distributed. In the standards and specifications for hygiene products, the formaldehyde test method is regulated for application with respect to three categories based on the type of product. The samples used in this study were of types for which method 1 or method 2 is applied, and the limits of detection, limits of quantification, linearity, and recovery rates were reviewed to verify the validity of each test method. When method 2 was applied, we experienced interference when performing analysis at a wavelength of 412 nm, which was associated with the influence of impurities in some samples of disposable cotton swabs and disposable diapers. Consequently, in these cases, the results were compared after analysis using method 1. By comparing the results obtained using method 2 with those obtained using method 1, the latter of which were unaffected by the interference of impurities, we were able to detect formaldehyde at low concentrations. These findings accordingly highlight the necessity to standardize the formaldehyde test method for future analyses.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.204-209
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• 2015

This study was carried out to investigate residual characteristics of insecticide acetamiprid in asparagus under greenhouse condition from July to August and consequentially to obtain basic data for guideline on safe use of this pesticide in asparagus. Residues of acetamiprid in young stem of asparagus before and after removing foliage were analyzed from samples harvested at 0, 1, 3, 5 and 7 days after single application before harvest. As a result, residues of acetamiprid in young stem of asparagus before and after removing foliage at 0 day were 0.27 mg/kg and 0.14 mg/kg, respectively, which were higher than tentative limit (0.1 mg/kg). However, 3 days later residues of acetamiprid were lower than the tentative limit, representing 0.08 mg/kg and 0.03 mg/kg in the asparagus before and after removing foliage, respectively. Acetamiprid was undetectable in both samples at 5 days since the concentrations were less than detection limit (0.02 mg/kg) in this study. In summary, the half-life of acetamiprid in asparagus regardless of removing foliage was quite short under greenhouse condition from July to August, in the range of 1-3 days, and single application of acetamiprid water dispersible granule in/on asparagus at 7 days before harvest would have no problem on safety issues about pesticide residue. This result might be basic information to construct guideline for safe use of acetamiprid in asparagus.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.210-217
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• 2015

Ipfencarbazone is a herbicide of the tetrazolinone class, and is believed to be an inhibitor of very long chain fatty acids (VLCFAs), which control cell division in weeds. The objective of this study was to develop and validate an official analytical method for ipfencarbazone determination in agricultural products. The ipfencarbazone residues in agricultural products were extracted with acetone, partitioned with n-hexane, and then purified through silica SPE cartridge. Finally, the analyte was quantified by gas chromatograph-electron capture detector (GC-ECD) and confirmed with gas chromatograph/mass spectrometer(GC/MS). The linear range of ipfencarbazone was 0.01 to 1.0 mg/L with the coefficient of determination ($r^2$) of 0.9999. The limit of detection (LOD) and quantification (LOQ) was 0.003 and 0.01 mg/kg, respectively. In addition, average recoveries of ipfencarbazone ranged from 80.6% to 112.3% at the different concentration levels LOQ, 10LOQ and 50LOQ, while the relative standard deviation was 2.2-8.6%. All values were consistent with the criteria ranges requested in the CODEX guidelines. Furthermore, and inter-laboratory study was conducted to validate the method. This proposed method for determination of ipfencarbazone residues in agricultural products can be used as an official analytical method.

• Journal of Environmental Impact Assessment
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• v.29 no.5
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• pp.350-362
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• 2020

In this study, nano Fe°-impregnated biochar (INPBC) was prepared using pruning residues and one-pot synthetic method and evaluated its performance as an amendment agent for the stabilization of arsenic-contaminated soil. For the preparation of INPBC, the mixture of pruning residue and Fe (III) solution was heated to 220℃ for 3hr in a teflon-sealed autoclave followed by calcination at 600℃ under N₂ atmosphere for 1hr. As-prepared INPBC was characterized using FT-IR, XRD, BET, SEM. For the stabilization test of as-prepared INPBC, As-contaminated soils (Soil-E and Soil-S) sampled from agricultural sites located respectively near E-abandoned mine and S-abandoned mine in South Korea were mixed with different of dosage of INPBC and cultivated for 4 weeks. After treatment, TCLP and SPLP tests were conducted to determine the stabilization efficiency of As in soil and showed that the stabilization efficiency was increased with increasing the INPBC dosage and the concentration of As in SPLP extractant of Soil-E was lower than the drinking water standard level of Ministry of Environment of South Korea. The sequential fractionation of As in the stabilized soils indicated that the fractions of As in the 1st and 2nd stages that correspond liable and known as bioavailable fraction were decreased and the fractions of As in 3rd and 4th stages that correspond relatively non-liable fraction were increased. Such a stabilization of As shows that the abundant nano Fe° on the surface of INPBC mixed with As-contaminated soils played the co-precipitation of As leaching from soil by surface complexation with iron. The results of this study may imply that INPBC as a promising amendments for the stabilization of As-contaminated soil play an important role.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.4
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• pp.296-306
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• 2014

This study was conducted to survey and analyze the quantity of various organic wastes and to vitalize the utilization of agri-food by-products as raw materials for Total mixed ration (TMR), to improve feed cost savings and the quality of animal products. On-the-spot obstacles for animal farmers, along with legal and institutional alternatives are presented. The results are as follows. First, organic wastes in Korea are managed by the Allbaro system created in the Wastes Control Act, which processes 10,488 tons of cooking oil waste, 832,493 tons of animal and plant residues, 5,740 tons of animal carcasses, 1,171,892 tons of animal residues, and 2,172,415 tons of plant residues including 12,905 tons of rice hull and bran, for a total of 4,205,931 tons. Raw materials for TMR, namely rice hulls and bran as well as plant residues, accounted for 51.7% of the total national organic waste. The top 10 municipalities process 76~100% of all organic wastes and a supply management system is needed for the waste. Second, the 10 major agri-food by-products used as raw materials for TMR are bean curd by-product, rice bran, oil-cake, brewers dried grain, Distiller's Dried Grains with Solubles (DDGS), barley bran, soy sauce by-product, citrus fruit by-product, mushroom by-product and other food by-product (bread, noodles, snacks, etc.). Third, the biggest difficulties in using agri-food by-products are legal obstacles. Because agri-food by-products are regulated as industrial wastes by the Waste Control Act, animal farmers that wish to use them have legal reporting obligations including the installation of recycling facilities. To enable the use of agri-food by-products as raw materials for TMR, waste management system improvements such as 'the end of waste status' and the establishment of more than 10 public distribution centers nationwide are deemed essential.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.136-145
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• 2020

This study was conducted to evaluate pesticide residues and foreign metallic matter on a total of 104 powdered agricultural products in Incheon. Residue testing for 373 pesticides was conducted by GC-MS/MS, LC-MS/MS, GC-ECD, GC-NPD and HPLC-UVD. Foreign metallic matter was detected by magnetic rod. As a result pesticide testing, 7 of the 104 products were found to be within the MRL of the pesticides. The detected pesticides were chlorpyrifos, etofenprox, fenoxanil, malathion, permethrin, tebuconazole and tetraconazole. As for foreign metallic matter, 16 samples were above the allowable limits set by Korean regulations. Therefore, the inspection of residual pesticides in raw material, and the removal of foreign metallic matter will require further stringent attention for the safety of powdered agricultural products.

• Journal of Food Hygiene and Safety
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• v.30 no.2
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• pp.196-201
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• 2015

This study was conducted to monitor the current status of pesticide residues and to calculate the correlation between monthly price fluctuation and distribution of pesticide residues in leafy vegetables at the whole market in Gyeonggi-do from 2009 to 2013. From the result, the maximum residue limit (MRL) were frequently exceeded in 5 leafy vegetables which were 48 cases of crown daisy (5.8%), 28 cases of chard (5.1%), 28 cases of spinach (3.4%), 25 cases of perilla leaves (3.4%) and 24 cases of chamnamul (3.7%). The high rate of monthly pesticide residues exceeding MRL showed on crown daisy and chard observed in June and September, spinach in October to November and December to January, perilla leaves in July to August and January, and chamnamul in August to September. To calculate the correlation between monthly price fluctuation and distribution of pesticide residues, we performed the Pearson's correlation analysis. From the results, there were significant differences between monthly price and pesticide residues detected in chamnamul, spinach and perilla leaves (p < 0.05). There were also significant differences between monthly price and pesticide residues exceeding MRL in chamnamul and crown daisy (p < 0.05). Although the small number of leafy vegetables and short period were analyzed in this study, the consolidation monitor of pesticide residues according to the season and price will be needed to acquire the safety of agricultural products.