This study utilizes association rule learning and clustering analysis to explore the co-occurrence and relationships within ecosystems, focusing on the endangered brackish-water snail Clithon retropictum, classified as Class II endangered wildlife in Korea. The goal is to analyze co-occurrence patterns between brackish-water snails and other species to better understand their roles within the ecosystem. By examining co-occurrence patterns and relationships among species in large datasets, association rule learning aids in identifying significant relationships. Meanwhile, K-means and hierarchical clustering analyses are employed to assess ecological similarities and differences among species, facilitating their classification based on ecological characteristics. The findings reveal a significant level of relationship and co-occurrence between brackish-water snails and other species. This research underscores the importance of understanding these relationships for the conservation of endangered species like C. retropictum and for developing effective ecosystem management strategies. By emphasizing the role of a data-driven approach, this study contributes to advancing our knowledge on biodiversity conservation and ecosystem health, proposing new directions for future research in ecosystem management and conservation strategies.

Estuary is important in terms of biodiversity because it has the characteristics of transition waters, created by the mixing of fresh- and seawater. The estuarine water circulation provides a variety of habitats with different environments by inducing gradients in the chemical and physical environment, such as water quality and river bed structure, which are ultimately the main factors influencing biological community composition. If the water circulation is interrupted, the loss of brackish areas and the interception of migration of biological communities will lead to changes in the spatial distribution of biodiversity. In this study, among the sites covered by the Estuary Aquatic Ecosystem Health Assessment, we selected study sites where changes in biodiversity can be assessed by spatial gradient from the upper reaches of the river to the lower estuarine area. The α-, γ- and β-diversity of diatom, benthic macroinvertebrates, and fish communities were calculated, and they were divided into open and closed estuary data and compared to determine the trends in biodiversity variation due to estuarine circulation. As results, all communities showed higher γ-diversity at open estuary sites. The benthic macroinvertebrate community showed a clear difference between open and closed estuaries in β-diversity, consequently the estuarine transects were considered as a factor that decreases spatial heterogeneity of their diversity among sites. The biodiversity trends analyzed in this study will be used to identify estuaries with low γ- and β-diversity by community, providing a useful resource for further mornitoring and management to maintain estuarine health.

We attempted to estimate potential habitats of Clithon retropictus and to determine the community structure of benthic macroinvertebrates by presence of C. retropictus. 2016 to 2018 database of “Survey and Assessment of Estuary Ecosystem Health” by the Ministry of Environment were used to identify the distribution site of C. retropictus. The occupancy model was applied to estimate the potential habitat of C. retropictus. Four diversity indices were used to confirm the community structure of benthic macroinvertebrates. C. retropictus was found in the southern coast area and part of the east coast, and this pattern was consistent with previous studies. Additionally, the occupancy model predicted that a potential habitat of C. retropictus could appear in the west coast area. The community structure of benthic macroinvertebrates was relatively high at the site with C. retropictus than the site without C. retropictus. Therefore, the occupancy model can be considered when conserving C. retropictus inhabiting a limited area. Additionally, C. retropictus can be used to the indicator species that can represent the brackish water environment.

This study analyzed the relationship between the community structure of benthic macroinvertebrates and habitat changes in open estuaries among the sites included in the national estuary monitoring program. The estuary survey was conducted under the “Guidelines for Investigation and Evaluation of Biometric Networks” and classified by sea area, 80 places in the East Sea, 102 places in the South Sea, and 19 places in the West Sea were investigated. In a total of 201 open estuaries, benthic macroinvertebrates were identified with 4 phyla, 9 classes, 41 orders, 139 families, 269 species and 196 species in the East Sea, 182 species in the South Sea, and 90 species in the West Sea. The highest population densities were Insecta in the East Sea, the Malacostraca in the South Sea, and the Annelida in the West Sea. Through SIMPER analysis, species contributing to the similarity of benthic macroinvertebrates communities in each sea area were identified. Some species greatly influenced the similarity of clusters. The benthic community in the East Sea was affected by the salinity, so the contribution rate of freshwater species was high. On the other hand, the benthic communities of the South and West Seas showed species compositions are influenced by the substrate composition. As results, the benthic macroinvertebrate community in Korean estuaries was impacted by salinity and substrate simultaneously, and the close relationship with geographical distance was not observed. The result of this study is expected to be used to respond to environmental changes by identifying and predicting changes in the diversity and distribution of benthic macroinvertebrates in Korea estuaries.

An estuary is an area where a freshwater river or stream meets the ocean. Even before the importance of the value of estuaries was recognized, the estuary was lost because of large-scale conversion by draining, filling, damming, and dredging. In South Korea, 643 estuaries are located, and the total area is 3,248,300 ha, accounting for 32.5% of the total area of South Korea. Over 35% of Korean estuaries are closed estuaries which are only temporally connected with the sea, either permanently or periodically. Since 2008, in order to preserve the estuary ecosystem and solve major issues in the estuary by accumulating knowledge about the estuarine ecosystem, the Ministry of Environment of Republic of Korea has been conducting the “Estuarine Ecosystem Monitoring and Assessment Project”. At 668 sites of 325 estuaries, epilithic diatom, benthic macroinvertebrate, fish, and vegetation are investigated, and the habitat condition of each site is evaluated using the newly developed biotic index. More than 100 researchers annually record 2,097 species of estuaries according to the standardized survey guidelines over the past 14 years and provide strictly managed data necessary for establishing estuaries conservation policies. As a result of bibliometric analysis of 1,195 research articles related to the monitoring and assessment of the estuarine ecosystem, research on pollutants such as heavy metals and sediment control have recently been conducted. “Estuarine Ecosystem Monitoring and Assessment Project” is an ecological monitoring type of long-term mandated monitoring that is usually focused on identifying trends. Although it is difficult to identify the mechanism influencing a change in an ecosystem through long-term mandated monitoring, providing empirical data for supporting evidence-based policy, decision-making, and the management of ecosystems. In order to increase the efficiency of the project, research to investigate the relationship between sediments and pollutants and organisms can be conducted at specific estuaries or sites to compensate for the shortcomings of mandatory monitoring.

한강수계 남한강의 보 (강천보, 여주보, 이포보) 공사 후 수변부 여울 구간의 물리적 환경의 변화에 따른 유수성 저서동물의 군집 변화를 확인한 결과 다음과 같은 결론을 얻었다. 첫째, 보에 의한 여울구간의 소실은 유속, 하상 등 물리적 환경의 변화를 야기하여 수질요인과는 독립적으로 수생태계에 영향을 미칠 수 있다. 둘째, 남한강 보 구간의 수변부 물리적 서식환경의 복합적인 변화는 유수성 분류군의 군집구성에 영향을 미친 것으로 판단된다. 셋째, 저서성 대형무척추동물 유수성 지표 후보종 157 분류군은 수생태계 변화의 원인 분석을 비롯한 하천 수생태계 복원 및 재자연화 등에 유용한 지표로 활용될 수 있을 것으로 기대된다. 넷째, 향후 유속변화에 대한 수생태계 영향을 면밀하게 파악하기 위해서는 분류군별 유속에 대한 저항성 또는 선호도를 바탕으로 한 지표연구가 필요할 것으로 사료된다.

First, a purified sludge was calcined at various temperatures viz. 800, 900, 1000, 1100 and 1200˚C per hour. Subsequently 100 wt% of ware from Geryong mountain was mixed with 5~25 wt% of a purified sludge. Then the ware was treated at 1250˚C in an electric kiln to test a bending strength. The physicochemical property of the prepared ware was characterized by XRD, Raman and SEM analysis. Among the different percentage, 25 wt% of a ware in a purified sludge calcined at 1000˚C showed 689 kg/cm2 strength. Also the purified sludge calcined at 1000˚C was adequate physical properties than the other composites. Further to enhance the physical strength, 3 wt% TiO2 (a mineralizer) was added into the ware and the strength was increased up to 731 kg/cm2. The composites exhibit absorption and porosity rates of 0.17% and 0.39% respectively.

Generally, the color gold has had a biased conception due to its traditional use. Thus, this bias has resulted in alack of usage of golden glaze on ceramics and also a lack of extensive studies of such glazes. In this paper, optimum conditionsand mechanism of formation of gold color crystallization glaze containing Fe2O3(hematite), which is developed for gold colorsof ceramic glazes, were studied. Experimental result showed that there are pyroxene based on diopside and TiO2 phase in thebase of a crystallization glaze with a value of TiO2 of 6wt% confirmed by XRD and Raman Spectroscopy. When Fe2O3 wasused as a colorant for the gold color, the TiO2 peak became extinct and the intensity of the diopside peak was sharper. Feldsparof 60wt%, talc of 20wt% and limestone of 20wt% were used as the starting materials and these were tested using a threecomponent system. The best result of test was selected and extended to its vicinity as an experiment to determine TiO2 andFe2O3 contents. The glaze with TiO2 of 6wt% and Fe2O3 of 12wt% addition showed stable pyroxene based diopside crystalsand the development of gold color. This gold color was obtained with CIE-L*a*b* values of 51.27, 4.46, 16.15 (a grayishyellow brown color), which was gained using the following firing conditions: temperature increasing speed 5oC/min, holdingfor 1h at 1280oC, annealing speed 3oC/min till 1100oC, holding for 2h at 1100oC, and finally natural annealing.

We collected Seokganju minerals (regions in Gyeryong Mountain, Sangsin-ri, Banpo-myeon, GongjuChungcheongnam-province), which were used as natural color pigments for grayish-blue during the 15th~16th centuries of theJoseon era, and investigated their crystallographic features to develop a black pigment having a spinel structure. By a Ramananalysis, the color of Seokganju under transparent glaze as a pigment for painting was black because hematite (Fe2O3) inSeokganju was converted to magnetite (Fe3O4) However, Seokganju into the transparent glaze as a pigment was brown becauseof hematite (Fe2O3) and small amounts of maghemite (γ-Fe2O3) in Seokganju minerals. Only Seokganju mineral is used, it isnot suitable for black pigment into the transparent glaze. This study tried to develop a spinel crystal black pigment stabilizedby Seokganju with CoO, Cr2O3, NiO, and MnO2 at 1280oC. A Raman spectroscopy analysis was performed to verify thepresence of Mn The results showed that it existed as spinel, and two crystal phases CoFe2O4 and MnFe2O4 were mixed.CoFe2O4 spinel has a dark grayish black color and Mn2O4 spinel has a greenish black color, and these two appeared as black.The color of a specimen calcined by adding 6wt% of pigment mixed with 5wt% of MnO2 added to lime glaze was analyzedwith a UV spectrophotometer. When applying the color pigment, it appeared black stabilized with L*24.23, a* 0.12, b* −2.29at 1260oC oxidative calcination, With 1240oC reduction firing, it is appeared black stabilized with low brightness of L* 23.13,a* −1.12, b* 0.54.

본 연구는 수조실험을 통하여 주꾸미, Octopus Ocellatus GRAY의 단지색에 대한 선택성을 조사하고, 전통적인 주꾸미 단지의 재질을 고둥껍질에서 PVC로 대체할 경우 그 가능성을 규명하기 위하여 PVC 시험 단지를 제작하여 1989년부터 1990년까지 해상실험을 실시하여 어획율을 조사하였다. 실험에서 얻은 결과를 요약하면 다음과 같다. 1. 수중실험에서 적색, 녹색, 황색, 백색, 회색중에서 주꾸미가 선호하는 색은 회색, 적색, 녹색, 황색, 백색순으로 나타났다. 2. 해상실험에서 주꾸미의 선호색은 회색, 홍색, 녹색순으로 나타났고, 이것은 수조실험의 결과와 일치한다. 3. 어획성능면에서 고둥껍질과 회색 PVC 단지의 차이는 거의 없었다. 4. 직경별 어획율은 40mm PVC 단지가 1.00, 50mm가 0.19로 나타났다.

2003년부터 시행된 우리나라의 대표적인 재활용제도인 EPR제도는 재활용품의 분리수거기반 조성 및 재활용산업을 활성화하는 견인차의 역할을 수행하였다. 그러나 제도운영 10년의 기간을 거치면서 재활용공제조합의 분리운영으로 인한 행정비용과다지출, 의무생산자의 개별위탁으로 인한 재활용 사업자간 과다경쟁심화, 낮은 재활용지원금으로 인한 재활용업체들의 채산성 악화 등 제도상의 여러 문제점이 발견되어 2013년 재활용촉진에 관한 법률이 개정되었다. 하지만 기본적으로 재활용사업자들이 재활용업체운영에 있어서 명확한 경제적 손익에 대한 분석이 이루어지지 않아 EPR제도의 가장 중요한 요소인 재활용지원금, EPR분담금, 재활용기준비용에 대한 설정이 매우 어려운 실정이며, 그 중에서도 가장 비율이 많은 합성수지류에 대한 회수 및 재활용단계의 경제성분석이 반드시 필요한 실정이다. 본 연구에서는 합성수지류 재활용품인 PET병, 단일재질용기류, 복합재질필름류 포장재에 대하여 회수 및 재활용업체 설문조사와 현장방문조사를 실시하여 현재 EPR제도상 합성수지류재활용품의 품목별, 단계별 표준프로세스를 설정하고, 그에 따른 회수재활용소요비용을 산출하여 손익정도를 분석한 후, 그에 따른 향후 재활용지원금 및 EPR분담금이 산정될 수 있는 기준을 마련하고자 하였다. 각 품목별 재활용지원금 및 분담금단가의 산정은 사회적인 표준인건비 및 적정 시설투자를 하였을 경우인 적정투자모델과 재활용업체가 적자를 메우고 수익을 창출하기 위하여 인건비 및 시설투자를 최소화한 현실투자모델로 나누어 산정하였다. 연구결과 재활용시장 활성화를 위하여 지급되어야할 회수재활용 적정 지원금은 적정투자모델Case PET병의 경우 무색 114.6원/kg, 유색 244.7원/kg, 복합재질 352.6원/kg, 단일재질용기류의 경우 116.2원/kg, 복합재질필름류의 경우 254.9원/kg의 재활용지원금이 필요한 것으로 분석되었으며, 현실투자모델Case PET병의 경우 무색 78.5원/kg, 유색 208.6원/kg, 복합재질 316.5원/kg, 단일재질용기류의 경우 77.6원/kg, 복합재질필름류의 경우 210.1원/kg의 재활용지원금이 필요한 것으로 분석되었다.

2003년부터 시행된 EPR(생산자책임재활용)제도는 우리나라의 대표적인 재활용제도로 재활용품의 분리수거기반 조성 및 재활용산업을 활성화하는 견인차의 역할을 수행하고 있다. 이러한 재활용업체를 중심으로 한 지원정책은 폐기물의 수요시장을 확대하여 폐자원 가격을 상승시킴으로 인해 폐자원은 모으면 돈이 된다는 시장 인식이 확산되고 있는 추세이다. 이러한 EPR제도의 운영에 있어서 가장 중요한 재활용 프로세스는 수집운반, 선별, 재생품생산의 단계로 나누어 지는데 본 연구에서는 그 중 선별단계에 대하여 대도시 S구의 종합선별장을 집중조사･분석, EPR대상 포장재의 선별현황에 대하여 연구하였다. 본 연구에서 주로 조사･분석한 내용은 종합선별장에서 EPR포장재 재활용품 반입, 선별, 잔재물처리까지의 물질흐름을 파악하고, 포장재별 반입량에 따른 선별량의 비율조사 및 분석, 버려지는 잔재물의 성상분석을 실시하여 재활용품의 발생부터 선별까지의 물질수지량을 분석함으로써 현재 대도시의 EPR대상 포장재의 수집운반, 선별현황을 파악하고자 하였다. 연구결과, 대도시 S구의 종합선별장의 2013년 재활용폐기물의 총 반입량은 13,855.680톤이며, 이 중 38.89%의 양인 5,388.309톤만이 품목별로 선별되어 재활용업체로 판매되는 실정이다. 선별된 재활용품의 품목은 파지, PET, PP, PE, PS, 철캔, 알루미늄캔, 백색폐병, 갈색폐병, 녹색폐병, 잉고트, 따대기, 고철, 의류, 비철, 잡선, 작업철, 생활철, 양은, 스템레스, 고무통, 신주, 필터, 생수통, 옷걸이, 키판, 중철, 잡병, 파동, 샷시, 아크릴로나위어 선별되고 있었다. 이 중 EPR대상 포장재의 선별량은 PET병이 964.340톤으로 가장 많았으며(17.9%), 플라스틱 단일재질인 PS(요구르트병 등)가 40.810톤으로 가장 적은양이 선별되고 있었다(0.76%). 또한 선별되지 않고 버려지는 선별잔재물에 대하여 성상분석을 한 결과, 복합재질 필름류인 포장비닐이 가장 많은 양인 3,696.272톤으로 가장 많이 재활용되지 않고 버려지는 것으로 분석되었으며, 재생가치가 높은 철캔, 알루미늄캔의 경우 거의 잔재물이 발견되지 않는 것이 확인 되었다. 본 연구를 통하여 현재 대도시의 선별장에서는 재활용쓰레기 중 약 39%의 재활용품만이 선별되어 재생용품으로 생산되고 있으며, 재생가치가 낮은 필름류의 경우 거의 재생되는 양보다 버려지는 양이 많다는 것을 알 수 있었다. 이렇게 버려지는 필름류의 경우에도 제대로 선별되어 재활용 된다면 양질의 고형연료 또는 재생유로 재활용되어 유용한 자원으로 쓰일 수 있기 때문에 이러한 버려지는 재홀용품의 선별량 확대를 위한 노력이 꾸준히 이루어져야 할 것으로 판단된다.