• Analytical Science and Technology
• /
• v.37 no.3
• /
• pp.174-188
• /
• 2024

This review summarized research trends regarding sample collection methods, pretreatment method, and types of analysis devices for microplastics (MPs) in soil and groundwater matrices. Soil sampling considers the selection of sampling location, depth, and volume. The typically sampling depth is within 15 cm (topsoil), and about 1 kg of mixed each sample. Among spot sampling and continuous flow sampling, groundwater sampling mainly used a continuous flow sampling, with collection rates 2 to 6 L/min in the range of 300~1,000 L, and followed by immediate on-situ filtration. Pretreatment method, applied to soil and groundwater, consist of organic digestion and density separation. In the organic digestion method, H₂O₂ is recommended among H₂O₂, acidic, alkaline, and enzymatic method. NaCl is primarily used as a reagent in density separation. However, depending on the density of MPs, other regents can be selectively used like ZnCl₂, ZnBr₂, and etc. Representative analysis device includes Fourier Transform Infrared (FTIR) and Raman spectroscopy for non-destructive analysis and Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC/MS) for destructive analysis. µ-FTIR and Raman can count MPs of larger than 10 and 1 ㎛, and analyze MPs materials. However, it is need to sufficiently remove interference, like organic matter, in spectroscopic analysis using essential pretreatment method. Py-GC/MS is being continuously researched because it doesn't require complex pretreatment method and allows quantitative analysis of specific materials.

• Korean Journal of Plant Resources
• /
• v.37 no.2
• /
• pp.214-224
• /
• 2024

In this study, the growth, physical characteristics of fruit and soil chemistry were investigated by grouping S. thea populations. The soil for each group was sandy loam or sandy loam, and it was analyzed to be slightly acidic to neutral, with a pH ranging from 5.6 to 7.0. Additionally, the leaf size was highest in the G7 group, and overall fruit growth was highest in the G1 group, confirming differences between the groups. The sweetness ranged from 16.8° Brix to 12.3° Brix, indicating a higher sweetness compared to Vaccinium oldhamill, blueberry, and blackberry. The correlation analysis between soil chemistry and S. thea growth characteristics revealed a significant negative correlation between calcium (Ca) and fruit growth characteristics. Furthermore, a significant positive correlation was observed between sodium (Na) and fruit acidity, as well as between cation exchange capacity (CEC) and fruit hardness.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.57 no.1
• /
• pp.1-14
• /
• 2024

We investigated the functional properties and in vitro bioactivity of protein isolates (RPIs) recovered from olive flounder Paralichthys olivaceus roes by isoelectric solubilization/precipitation process, according to pH-shift treatments. The buffer capacity of RPIs was shown to be stronger in alkaline pH than in acidic pH. Water holding capacity of RPIs was in range of 4.5-5.2 g/g protein with no significant differences (P>0.05). The foaming capacity and emulsifying activity index of RPIs did not show any significant differences between RPI-1 (pH 11/4.5) and 3 (pH 12/4.5), however they were superior to RPI-2 (pH 11/5.5) and 4 (pH 12/5.5). The 2,2'-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid radical scavenging activity of RPI-3 (2.5 mg protein/mL) was 102.4 ㎍/mL, and the angiotensin I converting enzyme inhibitory activity was 30.8%. Among the RPIs, RPI-3 was relatively superior in protein functional properties such as buffer capacity, foaming capacity, emulsification, and anti-oxidative activity. Therefore, we suggest that RPI prepared from olive flounder roes could serve as a potential food resource.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.27 no.1
• /
• pp.15-25
• /
• 2024

Purpose: This study aimed to investigate the presence of autoantigens in the gastric juices of children. Methods: Gastric juice and serum samples were obtained from 53 children <15 years of age who underwent gastric endoscopy. Among these, 8, 22, and 23 participants were in the age groups 0-5, 6-10, and 11-15 years, respectively. These samples were analyzed using two-dimensional electrophoresis (2-DE), immunoblot analysis, and matrix-assisted laser desorption ionization-time of-flight mass spectrometry. Furthermore, we reviewed the histopathological findings and urease test results and compared them with the results of 2-DE and immunoblot analysis. Results: There were no statistically significant differences in urease test positivity, grades of chronic gastritis, active gastritis, or Helicobacter pylori infiltration of the antrum and body among the three age groups. Three distinct patterns of gastric juice were observed on 2-DE. Pattern I was the most common, and pattern III was not observed below the age of 5 years. Histopathological findings were significantly different among active gastritis (p=0.037) and H. pylori infiltration (p=0.060) in the gastric body. The immunoblots showed large spots at an approximate pH of 3-4 and molecular weights of 31-45 kDa. These distinct, large positive spots were identified as gastric lipase and pepsin A and C. Conclusion: Three enzymes, which are normally secreted under acidic conditions were identified as autoantigens. Further investigation of the pathophysiology and function of autoantigens in the stomach is required.

• Korean Journal of Environment and Ecology
• /
• v.38 no.2
• /
• pp.156-168
• /
• 2024

This study was carried out to provide fundamental data for forest land and the environment by investigating the vegetation structure and soil properties of forest land where Sarcodon impricatus are present. The study area was divided into the Quercus mongolica community, dominated by Q. mongolica and the Quercus variabilis community, a mixed forest with Q. variabilis, Q. mongolica and Pinus densiflora. Also, Calamagrostis arundinacea in the former community and Disporum smilacinum and Carex siderosticta in the latter community showed significant levels as indicator species. Both communities showed a strong correlation between available phosphate and pH, sand, and clay, and the high organic matter content and slightly acidic pH of the soil are believed to be related to the development of S. impricatus. The species appearing at the lower layer continue to dominate because the species appearing at the upper layer have secured realized niches. The site was distributed in a relatively humid place in a north-east direction, and soil was developed with a thin litter layer and low rock exposure. In the selected S. impricatus growing areas, vegetation centered on highly adaptable species to disturbance or external interference was developed. Therefore, it is expected to be used as fundamental data to promote the occurrence of S. impricatus during artificial cultivation, as it is possible to identify the stand where S. impricatus occurs indirectly.

• The Korean Journal of Quaternary Research
• /
• v.34 no.1
• /
• pp.41-51
• /
• 2024

The Sincheon wetland shows a remarkable diversity of fluvial landforms, such as river islands, anastomosing channels, braided channels, and sand-gravel bars, which contribute to its rich ecological habitat. The wetland area is characterized by a ecological diversity of herbaceous and woody plants. Significant changes in land cover within the wetlands were observed from 2008 to 2020. Notably, there was a rapid decrease in agricultural area from 18% to 0.04%, while the vegetation area expanded from 45% to 54%. Concurrently, the water area also experienced a notable increase from 34% to 41%. The surface sediment composition in the studied area displays sandy loam characteristics and exhibits acidic soil properties. Sediment acidity tends to increase downstream and in the central part of channels. Variations in acidity are also observed at nearby collection sites due to the tributaries and local discharge. The presence of dense vegetation in river islands and bars has led to a significant transformation of sediments into soil, with this change being more pronounced downstream, particularly near the weirs. The installation of a weir in Sincheon wetland is believed to have a significant impact on altering flow velocities between upstream and downstream sections, as well as influencing erosion and sediment deposition patterns. However, given the formation of landforms in response to weirs, effective administration and management are essential to address potential risks of catastrophic environmental disruptions, such as the removal of weirs and/or the maintenance of river channels.

• Journal of Ecology and Environment
• /
• v.48 no.1
• /
• pp.24-31
• /
• 2024

Background: Honey from different geographical origins can have distinct characteristics due to variations in the floral sources available to stingless bees in different regions. The most abundant stingless bee for meliponiculture in Thailand is Tetragonula pagdeni. However, only a few studies about the properties of honey from a different origin were carried out. The objective of this study was focused on a comparative study to evaluate the melissopalynological, physicochemical, antioxidant activities, and total phenolic contents (TPCs) of stingless bee honey produced by T. pagdeni from different parts of Thailand. Results: Fifty honey samples were collected from five locations, and the physicochemical properties of T. pagdeni honey samples are acidic (pH 3.02-4.15) and have a high water content (18.42-25.06 %w/w), which is related to the regions of meliponary. Melisopalynological analysis reveals the predominant pollen from Melaleuca quinquenervia, Cocus nuciferca, Nephelium lappaceum, Salacca wallichiana, and multiflora honey. All honey samples were analyzed for their TPC and 2,2-diphenyl1-picrylhydrazyl radical scavenging activity. The results show that all samples had high TPC and antioxidant activities with a strong correlation (p < 0.05). Conclusions: The data from this study indicates the importance of geographical origin, which links physicochemical properties, phenolic compounds, and functional characteristics to their floral. Besides, the floral sources and harvesting location affected the properties of stingless bee honey. Our results identify Melaleuca honey as a promising source of phenolic content and antioxidant activity that can be used as a functional food, as well as multiflora and Cocus honey. However, further studies are required to characterize the phenolic compound and its biological potential, which could be a stingless bee honey biomarker and quality control, simultaneously with the physicochemical analysis.

• Resources Recycling
• /
• v.33 no.3
• /
• pp.30-37
• /
• 2024

In this study, we investigated the separability of vanadium and tungsten from spent SCR (Selective Catalytic Reduction) catalyst leach solution by reduction of vanadium and solvent extraction using Alamine 336 and conducted experiments to optimize process conditions. It is difficult to separate vanadium and tungsten due to their similar chemical behavior, but tungsten can be selectively extracted from acidic solution when vanadium extraction is prevented by reducing anionic pentavalent vanadium to cationic tetravalent vanadium. The results showed that NaHSO₃ was most suitable as a reducing agent, and the extraction efficiency of vanadium decreased and the separation efficiency increased as the amount of reducing agent added, reaction time, and temperature increased. When reducing NaHSO₃ 1.5 eq, 60 min, and 60℃, which are optimal conditions of reduction, vanadium and tungsten were effectively separated with vanadium extraction efficiency of 5.8%, tungsten extraction efficiency of 99%, and separation factor of vanadium and tungsten of 7,564.

• Korean Journal of Soil Science and Fertilizer
• /
• v.7 no.1
• /
• pp.29-34
• /
• 1974

On a newly reclamed acidic Song-jong soil (soil of a member of fine loamy, mesic family of Hapludults) an experiment was carried out to find out the proper measure of the improvement of soil fertility with soybean as test crop. Results are summarized as follow: 1. Application of compost (1 ton/10a), lime (lime requirement)and fused phosphate (equivalent to 5% of the phosphate fixation coefficient)resulted in the increase of soybean yield by 93.3% over the check plot (N: 6kg/10a, $P_2O_5$: 9kg/10a, $K_2O$: 6kg/10a). The application of fused phosphate at the level of 5% of phosphate fixation coefficient N (6kg/10a) and K(6kg/10a) brought the yield increase by 62.7% over the check plot. However, although the pH of the soil was adjusted to 7.0 by liming, the application of lime with moderate dose of phosphate ($P_2O_5$: 9kg/10a) did not increase the yield of soybean significantly. And the application of fused phosphate at the level of 5% of phosphate fixation coefficient increased the available soil P from 14 ppm to around 100 ppm as tested after harvest. 2. Application of compost (1 ton/10a) increased the organic matter content of soil by 0.8% when tested after harvest. While, the application of rice straw (0.5 ton/10a) did not alter the soil organic matter content. The CEC of the soil tested after havest found incereased significantly by the addition of lime and compost. 3. Plant analysis revealed that the $K_2O/Ca+Mg$ is better correlated with the yield than the absolute concentration of $K_2O$ in plant tissue. Between the concentration of $P_2O_5$ in plant tissue and the yield of soybean, a typical C-curve relationship was observed, indicating that in this particular soil, phosphate was the primary growth liming factor.

• Korean Journal of Soil Science and Fertilizer
• /
• v.7 no.1
• /
• pp.23-27
• /
• 1974

A pot experiment was carried out to investigate the effect of phosphate application and the adjustment of base saturation rate of soils on the growth of soybean. The soils used were very low in available phosphate (10-20ppm) and low in base saturation rates (less than 40%). Treatment included 2 levels of $P_2O_5$ $(40-80ppm){\times}3$ levels of base saturation rates (check, 60.80%) In adjusting the base saturation rate, the ratio between Ca and Mg was maintained at 65:15. Results are summarised as folloing. (1) The levels of phosphate in the experiment did not bring forth significant difference in the yield of soybean. Both 40 and 80ppm of $P_2O_5$ were seemed to be not enough to bring up the remarkable phosphate effect. (2) The increase in base saturation rate of the soils up to 60% proved to be significant in increasing the yield of soybean. Above that level, however, did not affect the yield. (3) The major factor for the increase of yield, in base saturation rate adjustments was the increased Mg-saturation rates. In the range of 10-15% of Mg-saturation rate of soils, there was a linear positive relationship between the yield of soybean and Mg-saturation rate of soils, while the optimum levels of Ca-saturation rates of soil were found to be 35-55%. (4) It was pointed that there is some possibility of relative in-sufficiency of Mg in Korean cultivated soils and that the continued application of liming materials which do not contain proper amounts of Mg may aggravate these situation.