• Journal of Korean Society on Water Environment
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• v.37 no.1
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• pp.1-9
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• 2021

The depletion of dissolved oxygen (DO) in urban streams has a profound effect on the aquatic ecosystem; however, the change in DO by resuspension of sediments and the cause have not been sufficiently investigated. In this study, the physicochemical properties (particle size, and the content of organic and heavy metals) of the sediments of an urban stream (Anyang Stream) and the characteristics of water quality changes (DO, dissolved organic carbon (DOC), dissolved nitrogen (DN), sediment oxygen demand (SOD), and adenosine triphosphate (ATP)) by sediment resuspension were investigated. The sediment content of fine particles (< 0.2 mm) increased from 36.7% to 52.7% from the upstream to the downstream, and the contents of heavy metals and organic matter of the sediment were also higher towards the downstream. The depletion of DO by resuspension was observed in the sediment at the downstream sites (P8, P9), where the fine particle content was high, and biological SOD (BSOD) was more than 88% compared to the total SOD. The increase in BSOD coincided with the increase in ATP. It was also confirmed that the depletion of DO could increase the amount of heavy metals (such as Fe, Mn, and Pb) released from the sediment. Based on the above results, it can be concluded that resuspension of sediments induces rapid water quality changes and may cause accidents, such as fish mortality, during rainfall, and such a water quality effect can be more pronounced in sediments with a high content of fine particles and organic matter and high biological activity.

• Journal of Soil and Groundwater Environment
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• v.28 no.5
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• pp.1-11
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• 2023

The phenomenon of sediment resuspension in rivers and lakes causes contaminants (heavy metals and nutrients) accumulated in the sediment to leach into the overlying water. As a result, it can lead to changes in toxic effects and eutrophication in the aquatic ecosystem. In this regard, it is important to quantitatively determine the amount of contaminants leached during sediment resuspension. In this study, methods for assessing the amount of released contaminants and the types of contaminants potentially released due to sediment resuspension were studied and summarized. Methods for assessing leaching can be divided into three groups based on the principle of causing resuspension: (i) the oscillating grid chamber method, (ii) the mechanical stirrer method, and (iii) the shaker method. It was confirmed that the types of contaminants that can potentially be released include heavy metals bound to sulfides, as well as exchangeable and labile forms of heavy metals and nutrients. To effectively manage stable aquatic ecosystems in the future, a simplified leaching test method is needed to assess in advance the risks (i.e., changes in toxic effects and eutrophication) that sediment resuspension may pose to aquatic ecosystems.

• Journal of Soil and Groundwater Environment
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• v.29 no.1
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• pp.72-83
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• 2024

Most of the slags generated from steel-making industry in Korea are recycled into media-contact aggregates such as fill and cover materials. For their use as media-contact aggregates, the slags must meet not only the waste quality criteria, but also the Daphnia magna acute toxicity test criteria. In this study, Korean Leaching Test ES 06150.e (Korea), Japanese Leaching Test JIS K 0058-1(Japan), Detuch Leaching Test DIN 19529 (Germany), Toxicity Characteristic Leaching Procedure (USA) were conducted for batch leaching test of slags from 6 Korean steel-making companies. In addition, Korean Standard up-flow percolation test (ES 06151.1) mimicking field conditions was conducted to assess the impact of the slag leachate on the surrounding environment indirectly. Heavy metals such as Cr⁶⁺ and Zn²⁺ were detected from both extractant and leachate samples, but all of them did not exceed waste quality criteria of each country. However, Daphnia magna acute toxicity tests using the leachate samples from up-flow percolation test with slag alone and slag/natural soil conditions exceeded ecotoxicity standard (TU=2) due to their high pH (11.3-12.5). After neutralizing the pH of the slag leachate to 6.5~8.5, the Daphnia magna mortality and immobilization were reduced to satisfy ecotoxicity standard. As the reducing pH of slag leachate would be extremely difficult, appropriate recycling management considering the physicochemical characteristics of he slags should be stuided further.

• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.102-109
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• 2018

In the present study, a variety of polylactide (PLA) articles (n = 211) were tested for migration of lead (Pb), cadmium (Cd) and arsenic (As) into the food simulant (4% v/v acetic acid). Pb, Cd, and As were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Migration tests were performed at $70^{\circ}C$ and $100^{\circ}C$ for 30 min. The amounts of Pb, Cd, and As increased at $100^{\circ}C$ for 30 min compared with levels at $70^{\circ}C$. However, the migration at both conditions was very low. The maximum level of Pb at $100^{\circ}C$ for 30 min corresponded to 1% of the migration limit. The estimated daily intakes (EDI) based on safety evaluation ranged from $2.5{\times}10^{-5}$ to $2.0{\times}10^{-3}{\mu}g/kg\;bw/day$ for Pb, Cd, and As. The EDI calculated from migration of Pb at $100^{\circ}C$ for 30 min in PLA was the maximum value, $2.0{\times}10^{-3}{\mu}g/kg\;bw/day$, which corresponded to 0.055% of provisional tolerable weekly intake (PTWI, $25{\mu}g/kg\;bw/week$). The data from this study represent a valuable source for science-based safety control and management of hazardous heavy metals migrating from polylactide food contact materials.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.14 no.1
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• pp.35-42
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• 2008

Twenty eight gas impermeable plastic films for food-contact application were collected in the domestic market and material and/or migration tests for overall migration, antioxidants, potassium permanganate consumption, heavy metal, and plasticizers were carried out. The average overall migration values for NY/PE or NY/LLDPE, PETP/PE, and PVDC packaging films obtained by using n-heptane as fatty food simulant were 7.6, 6.9 and 14.1 mg/L, respectively. These values were much lower than the limit values of 150 and 30 mg/L for polyethylene and polyvinylidene chloride prescribed in the Korea Food Code. In almost of the packaging materials tested, the antioxidants such as Irganox 1010, Irganox 1076 and Irgafos 168 were found. The migration test result showed that almost of all samples except PVDC film contained Irganox 1076 and Irgafos 168, while the maximum migration value of Irganox 1076 into n-heptane was found in the Ny/PE/LLDPE(15/25/50 ${\mu}m$) sample at the concentration of 216.9 ${\mu}g/g$. From the plastic packaging samples tested, plasticizers such as DEP, DPRP, DBP, DPP, BBP, DCHP, DEHP, DEHA and observed above the detection limit. Consumption amount of potassium permanganate was much lower than the limit value of 10 mg/L. In the material test for heavy metals, cadmium and lead were determined at the concentrations far below the limit value of 100 mg/kg. The migration test for cadmium and lead showed a lower value than the detection limit. Therefore, it can be concluded that the safety status of the plastic films tested met the requirement of limit values as prescribed for the material and migration tests of food packaging utensils, containers and packages of the Korea Food Code.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.840-850
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• 2010

The present study was attempted to find the effects of structural properties of phosphorus on the water quality of Gyehwa reservoir in Saemangeum. Relationship of phosphorus fractions between water and sediment properties was closely examined, and a few types of phosphorus were found from the sample sediment as : Saloid-P, Al-P, Fe-P, Ca-P, Red-P and Occd-P. Saloid-P (1.4%), Al-P (0.5%), Fe-P (39.8%), Ca-P (56.6%), Red-P (0.4%), Occd-P (1.3%) were extracted in a mass basis from the sediment of Gyehwa reservoir. Approximately more than 97% of phosphorus were calcium related phosphorus (Ca-P, 56%) and iron bound phosphorus (Fe-P, 39.8%). The Fe-P closely relates with water quality of T-N (r=0.761, p<0.05), $NO_3$-N (r=0.754, p<0.05), $NH_4$-N (r=0.728, p<0.05), T-P (r=0.774, p<0.05) and $PO_4$-P (r=0.767, p<0.05) while the Ca-P did not show any consistent dependency on the water quality. On the other hand, the correlation of Ca-P with $P_2O_5$ was high with r=0.783 (p<0.05) in the sediment. The Fe-P was affected significantly on the Ignition Loss (r=0.569, p<0.05), T-N (r=0.715, p<0.05) and T-P (r=0.983, p<0.01). In the research of correlation between phosphorus fraction and heavy metals in the sediment, Ca-P did not show any specific relationships with heavy metals. The Fe-P showed a significant correlation with As (r=0.817, p<0.01), Cu (r=0.793, p<0.05), Cd (r=0.786, p<0.05), Zn (r=0.738, p<0.05), so that it can be stated that the presence of Fe-P may implicate the volume of various metallic elements.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.78-85
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• 2007

This study provides an attempt to evaluate sanding wastes, generated from a chemical company as a reused adsorbent. Organic impurities in the raw sanding wastes were removed by calcination at $550^{\circ}C$. Aluminum was a major inorganic composition in the raw sanding wastes and increased from 29.09% to 52.73% after calcination. Dissolved concentrations of heavy metals from the calcined sample were below 0.3 mg/L in a stability test at pH 2. From the pH-edge adsorption experiments with the calcined sanding wastes, As (V) was found to follow an anionic-type adsorption. Adsorption isotherm obtained with variation of the dosage of the calcined sanding wastes was better described by Freundlich equation than Langmuir one. Freundlich constants of K and 1/n were 4.244 and 0.316, respectively. The As (V) adsorption capacity of calcined sanding wastes estimated from Langmuir isotherm was 13.25 mg/g. From this study, the calcined sample was identified as a good reusable adsorbent in the view point of stability and adsorption capacity on As (V).

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.304-314
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• 2010

This study was carried out to find out potential use of ochre as an agent to reduce phosphorus content in water. Ochre is a by-product from treatment of acid mine drainage (AMD) which is composed mostly of $Fe_2O_3$, $Fe_2O_3{\cdot}H_2O$, $FeO{\cdot}OH$ and $Fe(OH)_3$. Three ochre samples (ochre-H, ochre-D and ochre-S) were collected from three treatment facilities in Gangwon province. Physico-chemical characteristics of three ochre samples including pH, electrical conductivity, total phosphorus, available phosphorus, particle size distribution were analyzed. Scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray fluorescence (XRF) analysis were also carried out. In addition, experiments for phosphorus removal from water was performed. Calcium content of ochre-H was higher than that of ochre-D and ochre-S, whereas iron content of ochre-H was lower than that of ochre-D and ochre-S. All the phosphorus in water up to maximum 191,411 mg $kg^{-1}$ per unit mass of ochre was removed with ochre-H. Ochre has immense potential as an agent to reduce phosphorus content in water.

• Resources Recycling
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• v.20 no.1
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• pp.37-45
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• 2011

This study was conducted to recycle flotation tailings as non-sintered construction materials considering the economic and eco-friendly treatments. The particle size distribution( median $220\;{\mu}m$) of flotation tailings from Soon-shin mine was confirmed to be larger than that(median $140\;{\mu}m$) of tailings from Sam-kwang mine. Thus we investigated the properties of non-sintered eco-brick producted with the tailings from Sam-kwang mine and non-sintered water permeable block producted with the tailings from Soon-shin mine. Compressive strength of non-sintered water permeable block which was made with less than 25 wt% of tailings from Soon-shin mine was met with products class(over 14.70 MPa) of water permeable concrete(EL 245) from KEITL. Meanwhile, the coefficient of its permeability wasn't met with the products class( over $1.0{\times}10^{-2}\;cm/sec$). The properties of non-sintered eco-brick with less than 40 wt% of tailings from Sam-kwang mine were satisfied with third class in sintered clay brick products standard(KS L 4201). The non-sintered eco-brick as a result of leaching test on heavy metals by KSLT was verified to be environmentally stabile.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.673-680
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• 2017

Research and commercialization of wood chips-urethane resin mixtures as paving materials for park trails and tourist attractions are underway. The aim of this study was to expand the use of such paving materials to the playgrounds, where vigorous physical movements occur frequently. For this purpose, the physical properties and safety of the paving material, in which some or all of the wood chips(passing through a 10mm sieve and remaining in a 3mm sieve) were replaced with sawdust, were studied experimentally. Strength, elastic modulus, slip resistance, shock absorption and heavy metal content tests were carried out by varying the mixing ratio of urethane resin, sawdust and wood chip. As a result, in the case of wood chip-resin mixtures with mass ratios of the resin to total mass of sawdust and wood chips of 1.0 and 1.2 and having a ratio of sawdust mass to total mass of sawdust and wood chips of 0-0.4, it was found that the properties satisfied KS F 3888-2. On the other hand, in case of using sawdust only as a woody material, the shock absorbability was below standard, and the mass ratio of resin to sawdust required 1.2 or more to ensure the specified tensile strength.