• Korean Journal of Environmental Biology
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• v.41 no.2
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• pp.138-144
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• 2023

The main factor of biodiversity decline in major biological populations around the world is invasion of alien species. To protect native species, it is necessary to manage alien species. Recently, to eradicate ecosystem disturbance caused by alien species in Korea, many efforts have been made to capture individuals using nets and purchase captured individuals. However, there is no standard for classifying species due to the form of nest site or external characteristics of eggs of freshwater turtles. Thus, Mauremys reevesii eggs might be discarded due to mistaking as eggs of alien turtles. Based on more data, this study aims to compare and analyze external differences among eggs of Trachemys scripta elegans, Pseudemys concinna, and M. reevesii and use them as reference materials in the process of eradicating alien turtles. This study measured characteristics of eggs of the three turtle species. As a result of comparison, all variables of external characteristics of alien turtles and M. reevesii eggs showed significant differences. The shape of egg was also different, with eggs of T. scripta elegans and P. concinna showing a bicone shape and those of M. reevesii showing an ellipsoid shape. In conclusion, based on results of previous studies and the present study, eggs of M. reevesii, T. scripta elegans, and P. concinna are different in shape and structure. Thus, it is possible to distinguish between M. reevesii and invasive alien turtle using their eggs.

• Journal of Environmental Science International
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• v.11 no.11
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• pp.1149-1156
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• 2002

The ecological characteristics of Dolbae trees, a valuable genetic resource for native pyrus fruit trees, were investigated at four naturally inhabited areas on Mount Kaya, Gyeongsangnam-Do. Most Dolbae trees were found on the southwest side of an old hiking path to a mountain valley at altitudes of 610∼670 m. The surrounding flora consisted of 46 families, 69 genera, 75 species, and 10 varieties. The natural habitat of the Dolbae trees was basically a deciduous broad-leaved forest with a predominance of Quercus serrata and ligneous plants(xylophytes) from the Fagaceae and Betulaceae families. The habitat was also found to be in a second transition resulting from forest disturbance and exhibited a degree of diversity of 2.901-5.065, based on Shannon-Weiner's index. Examination of the Dolbae trees found in Mount Kaya revealed diameter breast heights(DBHs) ranging from 10 to 60 cm, including six old and large Dolbae trees with a DBH of 50∼60 cm, which will be particularly valuable as a genetic resource. Accordingly, the current results suggest that the study areas are a secondary forest in a typical mid-temperate zone resulting from forest damage about 10 years earlier.

• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.108-116
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• 2001

It is difficult to task to achieve high biological nutrient removal from municipal wastewater because of low organic content. Volatile fatty acids(VFAs) produced from acid fermentation of food wastes can be utilized as external carbon sources for the biological nutrient process. Significant reduction and stabilization of the food wastes can also be obtained from the acid fermentation. The objective of this study is to evaluate characteristics of acid fermentation of the food wastes. Results obtained from the batch experiment of various organic wastes showed that the food wastes had high potential to be used as an external carbon source because of the largest production of the VFAs with low nitrogen and phosphorus content. The fish waste was found to be the next possible organic waste, while the others such as radish cabbage and molasses waste showed high VFAs consumption potential as a results of high nitrogen and phosphorus content. alkaline hydrolysis of the food waste was carried out using NaOH prior to the acid fermentation. As the alkali addition increased, solubilization of the organics as well as TSS reduction increased. However, fraction of soluble COD to total COD became stable after a sharp increase. Alkali addition greater than 0.5g NaOH per g TS resulted in significant increase in pH.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.657-665
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• 2023

The root-lesion nematode Pratylenchus spp. is the most important plantparasitic nematode due to its worldwide distribution, wide host ranges, and migratory endoparasitic characteristics. One population of Pratylenchus collected from the giant pussy willow (Salix chaenomeloides Kimura) in the Andong area as part of a nematode survey in Korea was characterized morphologically and by molecular methods. The analysis of morphological measurements and morphometric characteristics, as well as DNA sequencing of the rRNA large subunit (LSU) D2/D3 expansion segments and the internal transcribed spacer (ITS) gene sequence, confirmed the identity of this population as P. hippeastri. This study is the first report of P. hippeastri associated with Salix chaenomeloides in Korea and worldwide. Further studies on distribution and pathogenicity in different P. hippeastri host crops, such as grapevines, strawberries, and apples, are necessary. The taxonomic keys to 16 Pratylenchus species in Korea are provided.

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.1-20
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• 2000

There are increasing evidences of climate change in the Antarctic and Arctic Oceans, especially elevated temperature due to the continuous burning of the fossil fuels and ultraviolet B(UV-B) flux within the ozone hole. Light-dependent, temperature-sensitive, and fast-growing organisms respond to these physical and biogeochemical changes. Polar marine phytoplankton, which are pioneer endemic species and important carbon contributors in the polar waters, are therefore highly suitable biological indicators of such changes. By virtue of light requirement, the primary producers are exposed to extreme seasonal fluctuations in temperature, photosynthetically active radiation, and UV radiation. Local environmental warming and increased UV-B radiation during ozone depletion may have profound effects on the primary producers that are primary carbon producers in the polar water. Small changes in climate temperature and solar radiation may have profound effects on the activity threshold of the polar phytoplanktion. To demonstrate biological response to the environmental changes, standardized representative natural and biological parameters are needed so that replicate samples (including controls) can be taken over extended periods of time. In this paper, we review general characteristics of polar phytoplankton, their environment, environmental changes in the polar waters, the effects on the environmental changes to the polar phytoplankton, and the importance of the polar phytoplankton to understand the global environmental changes. [Biological indicators, Global environmental change, Polar phytoplankton, UV].

• Journal of Species Research
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• v.7 no.3
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• pp.187-192
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• 2018

During a comprehensive study of indigenous prokaryotic species in South Korea, nine bacterial species in the phylum Bacteroidetes were isolated from freshwater environmental samples that were collected from three major rivers in the Republic of Korea. High 16S rRNA gene sequence similarity (${\geq}98.7%$) and robust phylogenetic clades with the closely related species suggest that each strain was correctly assigned to an independent and predefined bacterial species. There were no previous reports of these nine species in Korea. Within the phylum Bacteroidetes, four species were assigned to the genus Flavobacterium, order Flavobacteriales, and five species to three genera of two families in the order Cytophagales. Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source, and strain IDs are described in the species description section.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.244-248
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• 2013

This study was carried out to investigate the residual characteristics and calculate processing factor of the environment friendly material matrine in fresh chilli pepper by drying. Spray solution of matrine was prepared by dilution of the commercial product (2% active ingredient) with water at 1 : 1000 (v/v) ratio and sprayed onto chilli pepper plants at seven day intervals. Samples were collected at 0, 1, 3, 5 and 7 days after last application and then dried using a hot air dry oven at $60^{\circ}C$ for 36 hours until the water content was reduced to 14%. Recoveries and storage period stabilities of matrine in the samples ranged from 106.6 to 119.1% and 106.6 to 113.1%, respectively. The residual concentrations of matrine in fresh chilli pepper and dried chilli peppers treated only once were found to be from less than 0.01 to 0.11 and from 0.03 to 0.25 mg/kg, respectively. In case of plants sprayed twice with matrine, the residual concentrations ranged from 0.02 to 0.12 and from 0.04 to 0.4 mg/kg, respectively. Processing factor of matrine in the fresh chilli pepper by drying was found to be from 1.5 to 3.3, indicating that the residual concentration of matrine in dried chilli pepper increased about two or three times by drying.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.675-687
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• 2019

Objective: Methyl bromide (MB) fumigant has been shown to be fatal to human when was exposed. However, it were still used the significant amount in quarantine disinfection sites. The purposes of this study were to assess the MB exposure status and characteristics by fumigation-related workers and to provide supporting data for management plan. Methods: For this study, the three groups related to fumigation work were composed. A total of 107 workers were directly exposed, 20 field inspectors were indirect, and 20 general quarantines were not exposed. The urinary bromide ion concentrations in each group were analyzed by using HPLC/ICP-MS, and the working characteristics were identified using the structured questionnaire. Results: The urinary bromide ion concentration in the exposed group of fumigation workers was higher than the indirect and non-exposed groups. In the work characteristics of workers, there was a significant tendency to increase urinary bromide ion concentrations with higher fumigation work years (≤4 years: 2.84 (1.13-7.11) mg/g cr, >4-15 years: 5.36 (4.37-6.57) mg/g cr, >15-37 years: 6.69 (5.27-8.49) mg/g cr, p=0.034). In the comparison of the average number of working days per month, the more working days, the higher the urinary bromide ion concentration was statistically significant (≤12.5 days: 2.59 (1.19-5.65) mg/g cr, >12.5-19.25 days: 5.46 (4.62-6.44) mg/g cr, >19.25-27.25 days: 7.93 (5.93-10.59) mg/g cr, p=0.002). Conclusion: This study was the first nationwide survey including biological monitoring in workers exposed to methyl bromide. The results of this study were expected to be used as a reference for workers' health rights in relation to fumigation, prevention of addiction accidents, and safe management plan.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.39-44
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• 2015

Based on the 14 specimens collected from the Korean waters, we described the external morphology of Ocynectes maschalis in detail to provide morphological characteristics for species identification. The species from Korea is characterized by having a low first dorsal fin with a dark spot posteriorly, no dark blotches ventrally, three saddle-like blotches on dorsal midline posterior to the second dorsal fin, and two occipital cirri on head.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.269-276
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• 1995

An experimental research was conducted in order to study the treatability of municipal landfill leachate using a combined physio-chemical and biological treatment. The leachate was obtained from Nanjido landfill site in Seoul. Several sets of bench-scale sequencing batch reactor(SBR) and physic-chemical reactors were used as experimental apparatus. This experiment lasted for about 2 years. The results are as follows: 1. The characteristics of Nanjido landfill leachate were pH 7.4~8.2, BOD 79~450mg/L, COD 998~1460mg/L, $NH_3-N$ 1380~3412mg/L, 7-P 2.6~7.0mg/L, color 890~1992 unit, and heavy metals are a very small amount. 2. Either physio-chemical or biological treatment of Landfill leachate alone did not work well. So for the adequate treatment of leachate, it was necessary to deal with the physio-chemical pretreatment before biological treatment. And it was found that both electrolysis and ozone treatment are better pretreatments of leachate than others. 3. In this study, landfill leachate was effectively processed by two step : first by electrolysis pretreatment, and secondly by SBR treatment. Thus, the study showed considerable substrate removal of raw leachate, even though the rate of COD removal depended on HRT.