Two novel bacterial species, designated as CJ85T and CJ88T, were isolated from the agricultural soil and the Han River, South Korea, respectively. Cells of both strains were Gram-staining-positive, short rod-shaped, non-motile, and yellow-pigmented. Strain CJ85T exhibited optimal growth in tryptic soy broth at 37°C and pH 7.0 in the absence of NaCl. Strain CJ88T showed optimal growth in lysogeny broth at 30°C and pH 7.0 in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CJ85T belonged to the genus Paramicrobacterium, showing the highest sequence similarity to Paramicrobacterium fandaimingii HY82T (97.6%). Strain CJ88T was assigned to the genus Microbacterium, with the highest sequence similarity to Microbacterium azadirachtae DSM 23848T (98.5%). The DNA G + C content was 64.8% for strain CJ85T and 70.5% for strain CJ88T. The genome-based analyses, including phylogenomic tree, digital DNA-DNA hybridization, and average nucleotide identity, clearly indicated that these strains represent novel species within their respective genera. The major fatty acids of both strains were anteiso-C15:0, anteiso-C17:0, and iso-C16:0. Based on the polyphasic taxonomy study, strains CJ85T and CJ88T represent novel species of the genera Paramicrobacterium and Microbacterium, respectively, for which names Paramicrobacterium salitolerans sp. nov. and Microbacterium fluminis sp. nov. are proposed. The type strains CJ85T (= KACC 23064T = JCM 36217T) and CJ88T (= KACC 24080T = JCM 38050T).

The rapid development of the textile industry has led to the discharge of large amounts of dyes into aquatic environments, such as rivers and lakes. Long-term exposure to these substances causes many adverse health effects. Therefore, compact, highly sensitive sensors that enable rapid, on-site assessment of water quality have received significant attention. High-performance SERS substrates were successfully fabricated by optimizing and controlling the thickness of the shell of core-shell Au@Ag NPs by using both experimental and FDTD calculations. Results on the individual and simultaneous detection of dyes demonstrate the potential of Au@Ag NPs as substrates for environmental applications, where dyes exist in complex forms. Detection limits for the three organic substances, rhodamine B, crystal violet, and methyl orange, were 1.89 × 10-12, 6.57 × 10-13, and 1.08 × 10-9 M, respectively, demonstrating a significant improvement in sensitivity compared to single Au and Ag NPs. At the same time, tests in Han River water also demonstrated the high applicability of the SERS Au@Ag NP substrate in real samples. This is one of the advances in the development of SERS-based sensors for environmental applications. For the first time, the core-shell Au@Ag NPs were evaluated for their capabilities, including simultaneous detection and sensing in real water samples. This is of great significance in the application of this technique beyond the laboratory scale.

Enhanced prediction of total organic carbon in a large complex watershed (the Han River, South Korea) by integrating machine learning with real-time in-situ water quality parameters and fluorescence intensities.

Nitrate source apportionments in the South Han River basin and its main tributaries using multi-isotopes and Bayesian approaches.

The prevalence and diversity of carbapenem-hydrolyzing bacteria and β-lactamases in the aquatic environment of the Han River, South Korea

Phosphorus Source-Sink Characteristics in Sediments from Yangtze Connected Rivers and Their Response Mechanisms to Aquatic Organism Activities: A Case of the Han River and Jialing River

This study investigated heavy metal pollution in water bodies of metal mining areas in the Han River Basin (Shaanxi section), a critical water source for China's South-to-North Water Diversion Project. Water samples were collected from mining-affected areas, transition zones, and the main stem. Pollution levels, ecological risks, and health risks were assessed using the Nemerow Comprehensive Pollution Index, Potential Ecological Risk Index, and Health Risk Assessment models. The most severe pollution was found in mining-affected waters, where average Fe and Mn concentrations exceeded China's Class III standard by 4.8 and 3.5 times, respectively, and the maximum Cd concentration exceeded the standard by 2.9 times. The Nemerow index indicated moderate to severe pollution in mining areas (PN up to 4.21), transitioning to no pollution in the mainstream (PN < 0.7). Cd and Tl were identified as the primary ecological risk factors, with potential ecological risk indices (Ei) reaching 128.32 and 44.0, respectively. The health risks associated with drinking water ingestion were significantly higher than those from dermal contact, with Cd-induced carcinogenic risks for children as high as 5.12 × 10-5 a-1, far exceeding the acceptable level (1 × 10-6 a-1). Children were particularly vulnerable to elevated risks. Correlation and PCA analyses indicated that Cd, Pb, Fe, Mn, Be, and Ni originated mainly from mining activities, while Sb and Tl were influenced by both geological background and industrial sources. This study provides a foundation for targeted pollution control in high-risk areas.

IntroductionThe Han River Basin, a critical water source for the South-to-North Water Diversion Project, faces escalating eutrophication pressures due to intensive anthropogenic activities. This study aims to systematically evaluate the ecological responses of phytoplankton and bacterial communities to eutrophication gradients, and to elucidate their interactions for guiding ecosystem restoration.MethodsWater samples were collected from 15 sites across the Han River Basin in July 2023. Phytoplankton composition was identified microscopically (6 phyla, 33 genera), and bacterial communities were characterized via high-throughput sequencing of the 16S rRNA gene. Trophic states were assessed using a modified Carlson’s Trophic State Index (TSI). Relationships between environmental variables (TN, TP, Chl-a, COD, etc.) and community structures were analyzed via Monte Carlo tests, redundancy analysis (RDA), and co-occurrence network analysis.ResultsEutrophication Status: 75% of sites were eutrophic (TSI: 42.5–66.0), with significant spatial variations in TN (1.10–6.00 mg/L), TP (0.010–0.29 mg/L), and Chl-a (0.86–70.00 μg/L). Community Shifts: Phytoplankton dominance transitioned from Bacillariophyta in low-TSI areas to Cyanophyta in high-TSI regions. Bacterial communities were dominated by Proteobacteria (>60% abundance), with diversity declining as eutrophication intensified. Environmental Drivers: Monte Carlo tests indicated Chl-a and COD as key drivers for bacteria (p < 0.05), while TN primarily influenced phytoplankton (r = 0.39, p < 0.01). Network Interactions: Co-occurrence networks revealed increased negative correlations (0.32% to 0.61%) and reduced modularity (0.641 to 0.558) under eutrophic conditions, suggesting intensified competition.ConclusionEutrophication filters species adaptability, leading to deterministic succession in phytoplankton and homogenization of bacterial communities. The rise in negative correlations underscores escalating resource competition, potentially destabilizing ecosystem functions. Our findings emphasize the urgency of nutrient load reduction and adaptive management. Future studies should prioritize leveraging phytoplankton-bacterial synergism for bioremediation and resilience enhancement.

Transport and retention characteristics of floating debris in the Han River Estuary.

This study compares and evaluates the performance of a statistical model, Multiple Linear Regression (MLR), and a deep learning model, Long Short-Term Memory (LSTM), for predicting monthly mean temperature in the Han River Basin, South Korea. Predictor variables were dynamically selected based on lagged correlation analysis between climate indices and temperature over the past 40 years, identifying the top ten variables with the highest correlations for lag times ranging from 1 to 18 months. The MLR model was developed through stepwise regression with cross-validation, while the LSTM model was constructed using an 18-month input sequence to capture temporal dependencies in the data. Model performance was evaluated using percent bias (PBIAS), Nash–Sutcliffe efficiency (NSE), Pearson’s correlation coefficient (r), and tercile-based probability metrics. Both models reproduced the seasonal variability of monthly temperature with high accuracy (NSE &gt; 0.97, r &gt; 0.98). The LSTM model showed slightly higher predictive skill in several periods but also exhibited larger prediction variance, reflecting the sensitivity of nonlinear architectures to variations in predictor–response relationships. In contrast, the MLR model demonstrated more stable predictive behavior with narrower uncertainty bounds, particularly under low signal-to-noise conditions, owing to its structural simplicity. These findings indicate that the two approaches are complementary; the LSTM model better captures nonlinear temporal dynamics, while the MLR model provides interpretability and robustness. Future work will explore advanced hybrid architectures such as CNN–LSTM and Transformer-based models, as well as multi-model ensemble methods, to further enhance the accuracy and reliability of medium-range temperature prediction.

During the Three Kingdoms period, the Namhan River's flow from east to northwest, reaching the western sea, proved beneficial to Silla. It was a geographic structure that allowed Silla to maintain control of the Han River basin. After Silla took control of the Han River basin in 553, military supplies produced in Danyang, Jecheon, Chungju, and Wonju were distributed downstream. While Goguryeo and Baekje simultaneously attacked the Han River basin from both north and south, Silla's fortresses there remained intact. The Han River waterway was also utilized during the Silla-Tang War and the development of Paegangjin after unification. Of course, the people of the lower reaches of the Han River and the fortresses along the west coast did more than simply consume goods. One-way traffic diminished the sustainability of the flow. They were the guardians of the waterways that carried goods produced on the west coast upstream to the middle and upper reaches of the Han River, the overseers of the salt farms, and the primary agents of replenishing ships' stalls with seaborne produce. Passing vessels always sought a full cargo. Something had to be filled, and salt, with its widespread consumption, would have made up a large portion of the cargo on ships traveling up the Han River. His filled the salt warehouses of Wonju, Chungju, Jecheon, and Danyang, and to meet the demands of the Silla capital, salt flowed over the pass and into the Nakdong River basin. The salt that crossed Gyeripnyeong Pass likely traveled down the Nakdong River before entering its tributary, the Geumho River, where it was unloaded at Bongmu-dong in Daegu. It would then travel further upstream during the water-boosting period, where it was unloaded at Dodong in Yeongcheon City, and then overland to fill the salt warehouses of the capital. King Sinmun, feeling the burden of overland transportation between Daegu and the capital, attempted to relocate the capital to Daegu in 689, but was unable to achieve his goal. The Silla people were obsessed with residing in the royal capital. In the capital, which existed for a thousand years, the bone rank system, a typical caste system, emerged, and this system was limited to those living in the capital. For them, leaving the capital and moving their base to the provinces typically meant a decline in social status, as it meant being separated from the intermarriage rights of the capital residents. The bone rank system itself was a structure that concentrated the upper class in the royal capital. According to the Samguk Yusa (Memorabilia of the Three Kingdoms), 178,936 households lived in the royal capital, bringing the population close to one million. Even if one does not believe this, it is clear that the royal capital was overcrowded and overpopulated. The royal capital, with its high-ranking class, likely accounted for more than half of the nation's consumption. This doesn't mean the upper class consumed more salt. The number of nobles, along with the number of subordinates supporting them, increased, leading to a population concentration in the capital, spurring consumption. The massive demand for the capital demanded an influx of goods from the provinces. The Salt Way(鹽池通) weren't the only route for salt supply. The Samguk Yusa records the influx of salt from Gimhae to Gyeongju. This region was a salt-producing region. First, there was the sea second, the countless reeds and brushwood in the marshlands of the Nakdong River estuary provided fuel for boiling seawater in pots and third, the river provided a useful route for transporting salt inland. Salt was also produced in Pohang and Ulsan. Most importantly, they were close to the capital, a major consumer.

This paper examines the industrialization and modernization process of South Korea from the late 19th century to the late 20th century, focusing on the historical, political, and economic drivers led by Park Chung Hee. Rooted in Confucian heritage, the Kabo reforms, and the Japanese colonial experience, South Korea developed a strong awareness of education, science, and economic management. Park Chung Hee, with his strategic vision and political organizational skills, implemented five-year economic plans, established heavy and chemical industries, building POSCO, and research institutions such as KIST/KAIST, promoted exports, and introduced a model of “national capitalism” centered on large chaebols. Consequently, South Korea transformed from a poor agrarian society into a modern industrial nation, achieving 8-10% annual growth and becoming a regional economic power. The paper highlights the roles of education, practical learning (Silhak), collaboration with Japan, and innovation in industrialization. It also draws lessons on the importance of independence, self-reliance, and strategic adaptability for developing countries seeking rapid modernization and economic development.

The contemporary concept of the Jungwon Historical and Cultural Area derives from Jungwongyeong, a major regional center established during the Silla Dynasty. Centered on present-day Chungju, Jungwongyeong functioned as a strategic base for Silla’s expansion into the Han River basin and served as the kingdom’s secondary administrative center. As archaeological and historical evidence continues to accumulate, the historical reality of Jungwongyeong has become increasingly well defined. Nevertheless, further research is required to accurately identify the location of its administrative center and to reconstruct the city’s overall spatial structure. Until recently, attempts to identify the administrative center relied primarily on archaeological evidence. In this context, recent studies employing textual sources to delineate the territorial boundaries of Jungwongyeong are particularly significant. When these textual interpretations are synthesized with archaeological findings, the spatial extent of Jungwongyeong is shown to correspond largely with the present administrative boundaries of Chungju City. Current scholarship suggests that the administrative center was initially located in the Tappyeong-ri area of Jungangtap-myeon. Following the Silla–Tang War, however, the center appears to have been relocated to what is now downtown Chungju. This transition is supported by recent archaeological investigations at sites such as the Chungju Sago(National History Archives) Site and the Allim District excavation site. Evidence from the Ruam-ri and Ha-guam-ri tumulus clusters, the Tappyeong-ri site, and newly identified remains in central Chungju indicates that Silla’s political and military presence in the Jungwon region was firmly established by the mid-sixth century. By the late seventh century, a planned urban structure—centered on the area of the present-day Chungju Eupseong(walled town)—had clearly emerged as the administrative core, reflecting the relocation of the governing center from Tappyeong-ri to downtown Chungju. Finally, the identification of Gukwonseong, constructed in 673 CE during the reign of King Munmu, with the present-day Daerimsanseong is well supported. This interpretation is further supported by the broader international geopolitical context of the period, Silla’s heightened defensive posture following unification, and the material characteristics of Unified Silla–period artifacts excavated from the Daerimsanseong site.

The emergence of the Mahan Bungumyo society is estimated to be around the 2nd century BC to the 1st century AD, but the time when the Bungumyo society began to form in earnest can be seen as around the 3rd century AD. The pattern of Bungumyo, which had been distributed sporadically before, spreads throughout from the Han River to the Haenam Peninsula. In the Mangyeong River area, it is estimated that the first Bungumyo appeared in Sangun- ri, Wanju, and is believed to be around the first century BC, when the previous integrated togwang(a wooden coffin)tomb society declined. After the third century A.D., Bungumyo communities appeared throughout the Mangyeong River area, forming a full-fledged Bungumyo society. The main characteristic of the Bungu tomb during this period is the appearance of multiple burial facilities such as earthenware coffin and togwang tombs in one Bungu. When the types of multiple burial in the Mangyeong River area are largely classified, they are divided into the centered burial on the multiple burial, the non-centered burial subject, and the multiple burial through expansion. The first two types co-exist without any time difference, and it is understood that the multiple burial type through expansion occurred at a later time. The multiple burial type through expansion is thought to be a phenomenon in which the efficiency of the creation of the Bungumyo according to the development of society is reflected in the tomb. The Mahan Bungumyo society in the Mangyeong River area at the time examined through Bungumyo is presumed to be a village-centered community society similar to the traditional farming society in the past. There is no clear hierarchy between the burial facilities in Bungumyo, which requires a lot of labor, and a large-scale Bungu is created, but the aspect of burial facilities and burial relics is poor. These characteristics are difficult to understand as tombs for individual influential people or influential groups. Therefore, it can be presumed that Bungumyo Shrine at that time played a role in maintaining a village-centered community by developing mutual bonds and integration while creating a village's common grave together as a member or village cemetery. It is also confirmed that a common ritual was made through the special shape of earthenware, such as the Chukdong bungumyo, Gyenam Bungumyo. The timing of changes in the Bungumyo of the community society overlaps with the influx of Baekje-based material culture and the period of Baekje's entry into Mangyeong River area the after the mid-to-late 4th century. The burial aspect of Baekje relics in earnest in the Mangyeong River area can be seen from the late 4th to 5th centuries, and during this period, the amount of relics buried was abundant, and the hierarchy of the subject was clearly observed through special facilities or dignified items in the burial facilities. The type of multiple burial in the Bungumyo is became a main on the type of multiple burial through expansion, and the earthenware coffin decreases and the togwangmyo increases in the burial facilities. In particular, the Sangun-ri area of Wanju seems to show a pattern of changing the scale of society to a more efficient method as the ironware manufacturing industry has developed since the 4th century. After the 5th century, Baekje had a direct influence, such as creating a Baekje-based stone grave in the lower part of the Geumgang River, but the reason why the Bungumyo group in Sangun-ri, Wanju continued to develop can be assumed to be that the industry was progressing in a friendly relationship with Baekje in relation to the ironware manufacturing industry. By the second half of the 5th century, burial facilities in the Bungu were transformed into Baekje's stone chamber, and the tradition of Bungumyo was maintained until the first half of the 6th century, after that converted into Baekje culture.

In the mid to late 3rd century, during King Goi’s reign, the Yeongseo region of present-day Gangwon Special Self-Governing Province was incorporated into Baekje’s sphere of influence. Between the late 3rd and early 4th centuries, Silla advanced beyond the Jukryeong into the Yeongseo region, leading to conflicts between the two states. In the late 4th century, under King Geunchogo’s reign, Baekje came to control the political powers of the Wonju area, a fact that can be confirmed through tombs and artifacts excavated from the Beopcheon-ri site. In 396, Goguryeo launched a southern campaign and seized 58 fortresses and 700 villages from Baekje. Among them, Gomoruseong (古牟婁城), identified with present-day Wonju, was later renamed Pyeongwonseong (平原城). When Silla secured ten guns in the upper Han River region in 551, Wonju was incorporated into its territory, and Pyeongwongun (平原郡) was established there. After unification of the Three Kingdoms, Silla installed Bukwonsogyeong (北原小京) at Pyeongwongun in 678, both to effectively control the newly annexed former Goguryeo territories and the Yeongseo and Yeongdong regions of Gangwon, and to strengthen defenses against Tang forces advancing through the Jukryeong route following the Battle of Seokmun. With the completion of the Nineju (九州) system in 685, the security of Bukwonsogyeong was further consolidated. As tensions with Tang gradually eased, Bukwon, like other Sogyeong, acquired the character of a auxiliary capital(陪都), serving to reinforce nationwide governance. Its administrative seat was located in present-day downtown Wonju, and in the 5th year of King Sinmun’s reign (685), Bukwongyeongseong (北原京城), identified with today’s Geumdaeseong was constructed. The jurisdiction of Bukwonsogyeong encompassed present-day Wonju, Seowonmyeon in Hoengseonggun, and parts of Gangcheonmyeon and Buknaemyeon in Yeojusi, Gyeonggi Province. In 757, Bukwonsogyeong (北原小京) was renamed Bukwongyeong (北原京). In the late 9th century, Bukwongyeong was changed to Bukwonbu (北原府), and later, during Later Goguryeo, it was renamed Wonju (原州).

Review of the Status of Freshwater Fish Habitats in the Han River Estuary Wetland Protected Area in Korea

The endangered freshwater fish Gobiobotia brevibarba is endemic to Korea and threatened by habitat disturbance in major river systems. We investigated four wild populations from the Han River basin (IJR, BHR, NHR) and the Geum River basin (GR) using eleven microsatellite loci to assess genetic diversity, population structure, and contemporary gene flow. All populations showed relatively high genetic diversity (HO = 0.709–0.800, HE = 0.707–0.803) and no evidence of inbreeding, although bottleneck signals under the infinite allele mutation model were detected in IJR and BHR. Contemporary effective population size was large in IJR (Ne = 2463) and moderate in NHR (Ne = 467), whereas estimates for BHR and GR were imprecise. Genetic differentiation was very low within the Han River basin (FST = 0.009–0.027) but weak and significant between Han and Geum (FST = 0.085–0.096), and clustering analyses (STRUCTURE, DAPC, find.cluster) consistently supported K = 2, separating Han from Geum River. Gene flow analyses indicated extremely limited interbasin gene flow (&lt;4%) but asymmetric contemporary migration from BHR into both IJR and NHR; all other migration rates were similarly low. These results show that G. brevibarba currently maintains high genetic diversity and two basin-level genetic clusters, underscoring the need to manage Han and Geum River populations as separate units and conserve riffle habitats and longitudinal connectivity.

Carlson’s trophic state index (TSI) evaluates trophic status using transparency (Secchi depth – SD), chlorophyll-a (Chl), and total phosphorus (TP), while the trophic state index deviation (TSID) plot integrates their variability. This study applied TSI and TSID to assess eutrophication dynamics in South Korea’s Paldang Reservoir using monthly data from 2018 to 2022 collected at five sites influenced by the South Han River, North Han River, and Gyeongan Stream. TSI values indicated mesotrophic to eutrophic conditions, with the Gyeongan Stream-influenced site showing persistent eutrophy. Spatial patterns reflected tributary influence, while TSID plots confirmed phosphorus-limited conditions with strong seasonal variability. High-flow events affected nutrient ratios and biomass differently across sites. Compared with TP alone, TSID provided a more effective interpretation of hydrological–biological interactions. The results indicate that continuous, site-specific TSID monitoring is essential for adaptive management of large multipurpose reservoirs under changing hydrological and climatic conditions.

Introduction Cadmium (Cd) pollution poses a global environmental challenge, especially in the rapidly developing central Han River Basin. Cd contamination in farmland soil there is becoming increasingly serious, warranting studies on remediation using hyperaccumulators. Methods To explore the phytoremediation effects of different planting patterns on typical farmland soil (moisture soil) contaminated with Cd, two Cd hyperaccumulators ( Sedum alfredii and Solanum nigrum ) suitable for growth in Hubei Province and two common crops (celery and soybean) were selected for pot experiments involving monocropping and intercropping. Results The results showed that the absorption and accumulation of Cd by the two hyperaccumulators were as follows: Cd S. alfredii &amp;gt; Cd S. nigrum , and the Cd concentrations in plants were as follows: Cd shoot &amp;gt; Cd root , indicating a strong ability to transfer Cd from the root to the shoot. The Cd concentrations in each part of celery were as follows: Cd root &amp;gt; Cd steam &amp;gt; Cd leaf , while in soybean as follows: Cd root &amp;gt; Cd leaf &amp;gt; Cd steam . The Cd concentration in plants was significantly correlated with soil properties, negatively with pH (−0.68 ** ) and positively with both total and available Cd in the soil (0.99 ** ). The accumulation of Cd in plants in high-Cd soil treatments was significantly higher than that in low-Cd soil treatments ( p &amp;lt; 0.05). The accumulation of Cd in plants ranged from 0.04 to 1.02 mg, and the Cd removal rate from the soil was between 1.96 and 19.68%. Intercropping enhanced the overall remediation efficiency. In the S. alfredii -celery and S. nigrum -soybean systems, the biomass of crops increased, the Cd absorption by the hyperaccumulators was significantly increased ( p &amp;lt; 0.05). Discussion Both intercropping systems demonstrated relatively high soil Cd removal efficiency. Therefore, the two intercropping systems were suitable phytoremediation methods for Cd—polluted farmland soil in the central Han River Basin. Intercropping with the corresponding hyperaccumulators in fields of typical crops celery or soybean could reduce the food safety risk of these crops while simultaneously achieving phytoremediation.

Assessing climate change impacts on streamflow in upper Han River Basin using deep learning models ensembled with Bayesian model averaging