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Purpose The purpose of this study is to determine the level of health equity in relation to cancer incidence. Materials and Methods We used the National Health Insurance (NHI) claims data of the National Health Insurance Service between 2005 and 2022 and annual health insurance and medical aid beneficiaries between 2011 and 2021 to investigate the disparities of cancer incidence. We calculated age-sex standardized cancer incidence rates by cancer and year according to the type of insurance and the trend over time using the annual percentage change. We also compared the hospital type of the first diagnosis by cancer type and year and cancer incidence rates by cancer type and region in 2021 according to the type of insurance. Results The total cancer incidence increased from 255,971 in 2011 to 325,772 cases in 2021. The absolute difference of total cancer incidence rate between the NHI beneficiaries and the medical aid (MA) recipients increased from 510.1 cases per 100,000 population to 536.9 cases per 100,000 population. The odds ratio of total cancer incidence for the MA recipients increased from 1.79 (95% confidence interval [CI], 1.77 to 1.82) to 1.90 (95% CI, 1.88 to 1.93). Disparities in access to hospitals and regional cancer incidence were profound. Conclusion This study examined health inequities in relation to cancer incidence over the last decade. Cancer incidence was higher in the MA recipients, and the gap was widening. We also found that regional differences in cancer incidence still exist and are getting worse. Investigating these disparities between the NHI beneficiaries and the MA recipients is crucial for implementing of public health policies to reduce health inequities. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic has caused delays and restrictions in providing medical services. In response to the medical surge, countries with social insurance systems provided financial incentives to medical institutions. This study aimed to present the directions for health insurance support by comparing countries in terms of the domains and contents of COVID-19 health insurance support to ensure timely support in case of future pandemics. Methods: An analysis framework was developed to compare health insurance policy interventions for COVID-19 and non-COVID-19 domains, and detailed policy interventions were divided into sub-domains (space, staff, and stuff) for each domain. Data were collected by country from the websites of the Ministry of Health and Social Insurers, Organisation for Economic Co-operation and Development, and European Observatory on Health Systems and Policies and were analyzed using qualitative comparative analysis. Results: The countries provided comprehensive support for both the COVID-19 and non-COVID-19 domains. In the COVID-19 domain, overall support was provided in all three sub-domains. Additional cost support was provided to prevent infection and provide secure facilities to treat confirmed patients. Outpatient services were mainly supported, and an intensive intervention was developed in the staff sub-domain for the non-COVID-19 domain. The point of policy intervention was the surge of the first confirmed case. Continuous revisions were subsequently made. The government provided financial support through health insurance. Conclusions: Regarding where policy support through health insurance should be focused, the workload of medical personnel increased according to the change in the service provision environment due to the pandemic, and the medical service delivery system changed to prevent further infection. Consequently, incentives should be provided to aid the provision of stable services to patients and should be an auxiliary means to implement the national quarantine policy more effectively via a health insurance response system that promptly provides additional financial support in case of future crises. [ABSTRACT FROM AUTHOR]

Risk perception research, targeting the general public, necessitates the study of the multi-faceted aspects of perceived risk through a holistic approach. This study aimed to investigate the association between the two dimensions of risk perception of COVID-19, i.e., risk as a feeling and analysis, trust in the current government, political ideologies, and socio-demographic factors in South Korea. This study used a year-long repeated cross-sectional design, in which a national sample (n = 23,018) participated in 23 consecutive telephone surveys from February 2020 to February 2021. Most factors differed in the magnitude and direction of their relationships with the two dimensions of risk perception. However, trust in the current government, alone, delineated an association in the same direction for both dimensions, i.e., those with a lower level of trust exhibited higher levels of cognitive and affective risk perception. Although these results did not change significantly during the one-year observation period, they are related to the political interpretation of risk. This study revealed that affective and cognitive risk perceptions addressed different dimensions of risk perception. These findings could help governments and health authorities better understand the nature and mechanisms of public risk perception when implementing countermeasures and policies in response to the COVID-19 pandemic and other public health emergencies. [ABSTRACT FROM AUTHOR]

Biofouling is a significant means for introducing non-indigenous marine species internationally, which can alter habitats and disturb marine ecosystems. This study estimated the flux of ships' wetted surface area (WSA) to Korea in 2020 to assess the risks of biological invasion via biofouling on ships' hulls. The annual total WSA flux entering Korea was estimated to be 418.26 km2, with short-stay vessels (<3 weeks) contributing to 99.7% of the total WSA flux. Busan and Ulsan ports were identified as the main sources of high-risk flux, with container ships being a major vector in Busan and tankers in Ulsan. Gwangyang port had the third-highest total WSA flux, with nearly half of the flux driven from coastwise voyages, making it particularly vulnerable to the spread of hull fouling organisms. These findings could help enhance the management and inspection of hull fouling organisms in Korea. [ABSTRACT FROM AUTHOR]

Background: South Korea has utilized its National Health Insurance (NHI) system to adjust the medical fees payable for healthcare services, to financially support the frontline healthcare providers combating COVID-19. This study evaluated the composition of such adjustments to the medical fees—made to secure resource surge capacity against the pandemic—in South Korea. Methods: Descriptive statistics and schematization were employed to analyze 3,612,640 COVID-19-related NHI claims from January 1, 2020, to June 30, 2021. COVID-19 suspected and confirmed cases were evaluated based on the proportion of fees adjustment, classified into space, staff, or stuff (3S) using diagnosis codes. The proportion of fees adjustment was investigated in terms of the healthcare expenditure, number of patients, and number of healthcare services covered. Findings: First, in terms of cost, medical fee adjustments covered over 96% of the total costs arising from the increased demand for testing (stuff) and isolated spaces among patients suspected of having COVID-19. Second, medical fees were adjusted to cover over 80% of the cost attributable to COVID-19 confirmed cases, in relation to isolated spaces and medical staff support. Third, the adjustment of less than 10% of the various types of medical fees, if selected strategically, can effectively induce a surge in resource capacity. Interpretation: South Korea has improved its existing surge capacity by adjusting the medical fees payable through NHI to healthcare providers. Particularly, through the provider payment system of fee-for-service, the Korean government could prevent the spread of infection and protect the medical staff assigned to respond to COVID-19. However, additional studies on alternative payment systems are needed to control costs while maintaining an effective pandemic response system in the face of the prolonged COVID-19 outbreak. [ABSTRACT FROM AUTHOR]

Accessory minerals in granitic rocks are unlikely significant radionuclide contributions to groundwater due to their remarkable durability. However, accessory minerals incorporating U and Th may suffer structural damages due to the radioactivity and become highly susceptible to alteration. This study investigates geochemistry coupled with textural analysis of the U–Th bearing accessory minerals using a field emission scanning electron microscope and an electron probe micro-analyzer. Altered zircons with numerous open structures related to the radioactive decay show higher contents of U and Th and low analytical totals. Some thorites show high contents of U and non-formula elements due to the hydrothermal alteration in the metamicted thorite. The cerianite including U occurs as micro-veinlet in fracture with trace of Fe and Mn oxides, which indicates secondary phase formation from the decomposed accessory minerals in an oxidizing environment. Some accessory minerals with the high content of U and Th have been found in Mesozoic granite terrain in South Korea, where high concentration levels of radionuclide in groundwater were also reported. The leaching of U may be more likely when the accessory minerals are highly metamicted or altered as found in our samples. The altered zircon and thorite of the study area could be major carriers of radioelement in Mesozoic granitic aquifers where the occurrence of soluble U-minerals has not been reported. [Display omitted] • High radionuclides concentration in groundwater poses a threat to human health. • Accessary minerals can enrich groundwater with radionuclides in granite aquifers. • Altered zircons contain high U and Th levels with open structures. • Thorites show elevated U levels and non-formula elements due to alteration. • Metamicted and/or altered accessory minerals increase uranium leaching potential. [ABSTRACT FROM AUTHOR]

Background: Healthcare quality assessment is being conducted in many countries. Although improving health equity is one of the major objectives of medical quality assessment, it is not clear whether different socio-economic statuses show the same health outcomes even in the same medical quality hospitals. No study has directly compared the health outcomes of different socio-economic statuses in the same hospitals nationwide.Objective: To determine whether the mortality rate of acute stroke patients differs according to socioeconomic status.Methods: This study was a retrospective, observational study of patients who were subject to acute stroke quality assessment in 2013. A total of 10 399 stroke cases were included in the study. When evaluating the mortality rate, the researchers analysed 10 228 cases, after excluding 171 cases that were measured twice for the same person. The levels of socio-economic status were divided according to the use of medical benefits, either National Health Insurance (NHI) for general population or Medical Aid (MA) for the vulnerable. The primary outcomes measured according to socio-economic status were in-hospital mortality rate and 1-year follow-up mortality rate of stroke patients. The secondary outcome was the composite performance score.Results: MA recipients had a higher in-hospital mortality rate (12.5 vs. 8.3%, P < 0.001) and 1-year follow-up mortality rate (14.9 vs. 10.8%, P < 0.001) than NHI subscribers. MA recipients had slightly lower scores than NHI subscribers (83.2 vs. 84.4, P = 0.02). In hospitals of the same grade, MA recipients had lower performance scores than NHI subscribers, although the difference was not statistically significant.Conclusions: There is a difference in mortality and healthcare performance according to socio-economic status in stroke patients in Korea. Efforts to improve equity are needed, including the development and monitoring of equality indicators and developing policies for healthcare equity. [ABSTRACT FROM AUTHOR]

The effects of the unpredictability of the flow system in a karst area, with respect to bacterial communities in the aquatic environment, were evaluated. Bacterial communities from two different types of flow conditions (spring and sinkhole) were characterized and compared in the karst area. Proteobacteria, Bacteroidetes, and Verrucomicrobia were the major phyla present in the sampled spring and sinkhole waters. The water samples from the spring points were heavily loaded with Actinobacteria, especially Firmicutes, which accounted for 4.3% of the bacterial content. Furthermore, Actinobacteria were prevalent in some water samples, serving as indicators of the effects of seawater inundation. The richness and diversity of bacterial species were evaluated at the spring and sinkhole water points. The spring waters showed a higher bacterial richness and diversity compared to the sinkhole waters. Our results provide valuable information for the evaluation and investigation of microbial compositions in karst areas, which are characterized by heterogeneous hydrological conditions. The microbial species in karst areas are already exposed to changing hydrogeological conditions, and are likely to be confronted with future changes; thus, their spatiotemporal variations reflect the shifting baselines of physicochemical and ecosystem processes. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the optimal entomopathogenic fungus for the simultaneous control of the adults of two mosquito species, Aedes albopictus and Culex pipiens. The pathogenicity and virulence against the two species of mosquitoes were evaluated by using 30 isolates of Beauveria bassiana, an entomopathogenic fungus isolated from Korea that has high thermotolerance and UV-B tolerance. Regarding pathogenicity, 23 isolates were pathogenic to Ae. albopictus and 12 isolates were pathogenic to Cx. pipiens; Ae. albopictus adults were more susceptible to B. bassiana than Cx. pipiens adults. Among the isolates, 6 isolates that were simultaneously pathogenic to the two species of mosquitoes were used to evaluate virulence and conidia productivity. B. bassiana CN6T1W2 and JN5R1W1 had higher virulence than the other isolates, and they were more virulent in Ae. albopictus than inCx. pipiens. The conidia productivity of B. bassiana JN5R1W1 on millet grain medium was higher than that of B. bassiana CN6T1W2. Based on these results, B. bassiana JN5R1W1 was selected as the most efficient isolate for the simultaneous control of the two mosquito species. B. bassiana JN5R1W1 can be used effectively in the development of fungal insecticides to simultaneously control Ae. albopictus and Cx. pipiens adults with similar distribution areas. [ABSTRACT FROM AUTHOR]

Background: The epidemiology of the association between psoriasis and inflammatory bowel disease is poorly defined and remains controversial.Aim: To evaluate the prevalence of inflammatory bowel disease in patients with psoriasis compared with the general population.Methods: We searched the nationwide health claims database between 2011 and 2015 and evaluated the prevalence of inflammatory bowel disease, including Crohn's disease and ulcerative colitis.Results: Prevalence of inflammatory bowel disease, Crohn's disease and ulcerative colitis in patients with psoriasis vs the general population in 2011 were 0.16, 0.05 and 0.12% vs 0.08, 0.03 and 0.06%, respectively, which increased significantly with time between 2011 and 2015. Patients with psoriasis consistently revealed higher standardized prevalence (age and sex adjusted) of inflammatory bowel disease, Crohn's disease and ulcerative colitis compared with the general population. Subgroup analysis revealed the highest risk of prevalent inflammatory bowel disease in patients younger than 19 years (crude odds ratio 5.33, 95% confidence interval 3.74-7.59). Severe psoriasis demonstrated higher odds of inflammatory bowel disease (odds ratio 2.96, 95% confidence interval 2.54-3.45) than mild psoriasis (odds ratio 1.68, 95% confidence interval 1.51-1.88).Limitations: Limited data for doing adjustment and cross-sectional study design.Conclusions: Psoriasis patients revealed higher risk of inflammatory bowel disease. In particular, young patients and those with severe psoriasis may require closer monitoring and comprehensive management. [ABSTRACT FROM AUTHOR]

Background: Low socioeconomic status can increase the risk of adverse pregnancy outcomes, but it remains unclear whether this negative association is attributed to inadequate prenatal care. Korea has been adopting a universal healthcare system. All Korean citizens must be enrolled National Health Insurance (NHI) or be recipient of Medical Aid (MA). In addition, Korean government launched a financial support system for antenatal care for all pregnant women in 2008. Therefore, in theory, there is no financial barrier to receive prenatal cares regardless of someone's social class. However, it is still unclear whether adverse pregnancy outcomes observed in low-income women are attributable to low SES or to economic barriers specific to the utilization of medical services. The purpose of this study was to investigate whether socioeconomic status affects pregnancy outcomes after the introduction of this support system, which allows all pregnant women to receive adequate prenatal care regardless of socioeconomic status. Methods: Using the National Health Insurance database in Korea, we selected women who gave birth between January 1, 2010 and December 31, 2010. As a proxy indicator reflecting socioeconomic status, we classified subjects as MA recipient ("low" SES) or a NHI beneficiary ("middle/high" SES). Results: In the MA group, 29.4% women received inadequate prenatal care, compared to 11.4% in the NHI group. Mothers in the MA group were more likely to have an abortion (30.1%), rather than deliver a baby, than those in the NHI group (20.7%, P < 0.001). Mothers in the MA group were also more likely to undergo a Caesarean delivery (45.8%; NHI group: 39.6%, P < 0.001), and have preeclampsia (1.5%; NHI group: 0.6%, P < 0.001), obstetric hemorrhage (4.7%; NHI group: 3.9%, P = 0.017), and a preterm delivery (2.1%; NHI group: 1.4%, P < 0.001) than those in the NHI group. Conclusions: Women in the MA group tended to show higher rates of abortion, Caesarean delivery, preeclampsia, preterm delivery, and obstetrical hemorrhage than those in the NHI group Therefore, health authorities should consider investigating what kind of barriers exist or what factors may affect these inequitable outcomes. [ABSTRACT FROM AUTHOR]

Background: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening diseases; however, it is hard to estimate their incidence due to the rarity of these diseases. We evaluated the incidence of SJS and TEN using a nationwide administrative database. Methods: We used a national medical insurance review system (Health Insurance Review and Assessment) database which contained the claim data of the entire nation from 2009 to 2013 to estimate the accurate incidence of SJS and TEN in Korea. The diagnostic codes of L511 (SJS) or L512 (TEN) from the International Classification of Diseases-10th revision were used to define the target study population. We also retrospectively followed up a 2011 SJS and TEN cohort for 24 months in order to assess the in-hospital mortality, related complications and total claims cost due to SJS and TEN. Results: A total of 1,167 (938 SJS and 229 TEN) cases were newly diagnosed from 2010 to 2013. The age- and sex-standardized annual incidences estimated in this study were 3.96 to 5.03 in SJS and 0.94 to 1.45 in TEN per million. There was no significant change in annual incidence throughout the study periods. When analyzed by 10-year age groups, the annual incidence was the lowest in group 20–29 years and the highest in group 70 for both SJS and TEN. Based on the 2011 cohort analysis, the in-hospital mortality were 5.7 and 15.1% for SJS and TEN, respectively. The mortality increased with age, particularly, after 40 years of age. Among the complications related with SJS or TEN, ocular sequelae was the most common (43.1 and 43.4% of SJS and TEN patients, respectively) followed by urethral sequelae (5.7 and 9.4% of SJS and TEN patients, respectively). Conclusion: Overall, our data suggest that SJS, and TEN are infrequent but constantly arise throughout the years. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to identify private clinics that have a potential to perform the role of primary care providers (PCPs) in a primary care setting in Korea where private specialists are dominant. Methods: The 2013 National Patient Sample claim data of Health Insurance Review and Assessment Service in Korea was used. Two-step cluster analysis was performed using characteristics of private clinics, and patient and utilization characteristics of 27,797 private clinics. External validation of clusters was performed by assessing the association among clusters and outcomes of care provided by private clinics. Stability of clusters was cross-validated using discriminant analysis. Results: The result classified more than a half of private clinics into a potential PCP cluster. These were private clinics with specialties considered to be those of primary care physicians and were more likely to be located in non-metropolitan areas than specialized PCPs were. Compared to specialized PCPs, they had a higher percentage of pediatric and geriatric patients, patients with greater disease severity, a higher percentage of patients with complex comorbidities or with simple or minor disease groups, a higher number of patients and visits, and the same or higher quality of primary care. The most important factor in explaining variations between PCP clusters was the number of simple or minor disease groups per patient. Conclusion: This study identified potential PCPs and suggested the identifying criteria for PCPs. It will provide useful information for formulation of a primary care strengthening policy to policy makers in Korea as well as other countries with similar specialist-dominant primary care settings. [ABSTRACT FROM AUTHOR]

Based on water chemistry data, a rockfill dam in South Korea was investigated to identify major parts of substantial dam water leakage. Sinkholes in the dam crest and abnormal water leakage through the dam were observed since the first impounding of the dam. Previous investigations, including observational drillings, hydraulic tests, geophysical surveys, and tracer tests, revealed the development of a high permeability zone in the clay core and an abnormally high phreatic line zone in the left embankment. Sequential tracer tests provided further evidence of locations of preference and rapid water leakage pathways. In this study, we examined the usefulness of water chemistry data to confirm previous findings of water leakage. Factor analysis of the water chemistry data revealed major processes controlling the chemical composition, which include the wash-out and successive dissolution of fill materials in the dam interior, interaction between percolating water and dam core materials, and contamination of seeping water by grouting materials and previous tracer tests. Distinct spatial distribution of similar chemical groups was illustrated by cluster analysis and confirmed the location of major water leakage at the left abutment adjoining the spillway. [ABSTRACT FROM AUTHOR]

Karst regions cover approximately 10% of the Korean Peninsula and are highly vulnerable to contamination. In this study, five field surveys were conducted between 2017 and 2019 to examine the monthly and seasonal changes in the hydro-environment of a characteristic karst region in Samchoek, South Korea. During the surveys, a total of 24 surface water samples were collected and analyzed for field water quality parameters, major and minor ions, and stable isotopes. The results indicate that the water quality in the study area is significantly affected by precipitation. Overall, the water was classified as a Ca-Mg-HCO3 type, and correlation analysis of the major ions detected in the water samples indicates that the inflow of nitrate to the surface water originated from agricultural activities in the region. Furthermore, variations caused by climate were verified using the relationships between the various ions. In addition, high precipitation rates during the rainy season cause the active exchange of surface material, which was verified using stable isotope outliers. The results provide a scientific basis for studying the connectivity of water systems in complex karst hydrogeological regions and can aid future sustainable management of water resources in these regions. [ABSTRACT FROM AUTHOR]

This study analyzed the hydrochemical characteristics and microbial communities of karst water in Samcheok, Korea, and compared water quality results to identify the seasonal characteristics and hydrogeological connectivity of the study areas of Hamaengbang-ri, Gyogok-ri, Yeosam-ri, and the downtown area of Samcheok. Field survey and water quality analysis were performed in July 2019, February 2020, and April 2020. Hydrochemical analysis of karst water (groundwater and surface water) showed that most samples were comprised of Ca-HCO3 and that water–rock interactions were a dominant factor compared to precipitation and evaporation (crystallization). For seasonal characteristics, water–rock interactions appeared more active in the dry season than in the rainy season. Calcite weathering was dominant in the dry season, whereas dolomite weathering dominated the rainy season. Moreover, the saturation indexes for the dry and rainy seasons were less than and greater than 0, respectively, corresponding to an unsaturation (oversaturation) state; thus, white precipitate distributed in the study areas was deposited in the rainy season. Finally, as a result of analyzing the hydraulic characteristics between regions, hydrogeological similarities were identified between Hamaengbang-ri and Yeosam-ri, and between Gyogok-ri and downtown Samcheok, which suggested hydrogeological connectivity between each of the pairs. [ABSTRACT FROM AUTHOR]

Under changing climate, increasing groundwater use has risen the concern for groundwater quality variations over recent years, to maintain a healthy ecosystem. The objectives were to identify trend of temporal variations in groundwater quality and its suitability for different uses in Republic of Korea. Water quality data were collected from 198 monitoring stations of Groundwater Quality Monitoring Network (GQMN), annually for the period of ten years (2008–2017). Non-parametric trend analysis of a Mann–Kendall test and Theil–Sen's slope was done on groundwater physico-chemical data of ten years. Groundwater suitability evaluation was done for use in main sectors including domestic (drinking) and agriculture (irrigation). For drinking suitability analysis, results were compared with World Health Organization (WHO) and Korean Ministry of Environment (KME) established guidelines. For irrigation suitability evaluation, electrical conductivity (EC), Sodium Adsorption Ratio (SAR), percent of Na+, Residual Sodium Carbonate (RSC), US Salinity Laboratory (USSL), and Wilcox diagram were used. Most significantly, water type belongs to Ca-HCO3 and Ca-SO4 types, but a small proportion belongs to Na-CO3 and Na-Cl types. Approximately, 96% and 93% of groundwater samples are suitable for drinking, based on WHO and KME guidelines, respectively. Around 98% and 83% of groundwater samples are in suitable range for irrigation use, based on USSL and Wilcox diagrams, respectively. [ABSTRACT FROM AUTHOR]

Background: Autism spectrum disorder (ASD) is characterized by continuous impairment in communication and social interaction and by limited and repetitive behaviors, interests, or activities. Behavioral, educational, and pharmaceutical interventions have been shown to reduce behavioral disabilities, improve verbal/non-verbal communication, and help patients acquire self-reliance skills. However, there has been a lack of systematic verification and consensus regarding the treatment of the core symptoms of ASD because of its unclear etiology. Ukgansangajinpibanha (UGSJB), a legitimately prescribed herbal medicine for nervousness, insomnia, night crying, and malnutrition in South Korea and Japan, has been used for angry, sensitive, nervous, and unsettled children with ASD.Methods/design: This trial is a prospective, multicenter, randomized, double-blinded, placebo-controlled, parallel-group, clinical trial. The 4- to 6-year-old children with ASD will be randomly assigned to following groups: 1. A UGSJB granule with acupuncture, twice daily (n = 120) 2. A placebo group with acupuncture, twice daily (n = 120). The following outcome measures will be used: behavior by the Childhood Autism Rating Scale, Autism Behavior Checklist, and Aberrant Behavior Checklist; social maturity by the Social Maturity Scale; quality of life by the Child Health Questionnaire and EuroQoL Five-dimension Five-level Youth; and parental stress by the Parenting Stress Index at baseline and at 6, 12, and 24 weeks after the beginning of treatment. In addition, to evaluate safety, we will investigate the adverse reactions that may be caused by UGSJB granule. Finally, we will make an economic evaluation of UGSJB for the treatment of ASD.Discussion: We prepared a well-designed clinical trial to investigate the safety and effectiveness of UGSJB on ASD symptoms compared with placebo treatment. The results from this study will provide clinical evidence on the safety, effectiveness, and economic value of UGSJB combined with acupuncture in children with ASD.Trial Registration: Clinical Research Information Service: KCT0003007 (registered on April 5, 2018). [ABSTRACT FROM AUTHOR]

This study evaluated temporal and spatial variability of groundwater and stream water fluxes using multiple temperature time series. The study area is located in Inbuk stream, Gangwon Province, Republic of Korea. Total annual precipitation was 698.5 mm in 2014 (1210.5 mm, over the last 30 years). For the study, temperature loggers were installed at depths of 0.1, 0.2, 0.3, 0.4, and 0.5 m at five points with at 10 m intervals (IST1, IST2, IST5, and IST6) in the streambed. Temperature data was continuously measured every two-hours from June 1 to November 30, 2014. Vertical fluid flow (seepage flux) were calculated using the VFLUX program, which uses temperature time series data measured at different depths by temperature loggers in the hyporheic zone. The results of flux calculations Inbuk stream show that vertical flux rates at four locations are generally upwelling condition in the dry season and downwelling condition in the wet season. This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2015R1A4A1041105). [ABSTRACT FROM AUTHOR]

The objective of this study is to examine groundwater responses before and after the November 15, 2017 Pohang earthquake (Mw=5.4) in a coastal area of Korea. The earthquake caused devastating damages to many buildings in the city. For this study, groundwater monitoring data (water level, electrical conductivity, water temperature) were obtained for January 2016 to February 2018 from the national groundwater monitoring stations, the rural groundwater monitoring wells, and the seawater intrusion monitoring wells and they are located within 25 km from the epicenter. There are eight national groundwater monitoring stations (PSG, PYI-D, PYI-S, PGB-D, PGB-S, PJH, PDH, PGR), five rural groundwater monitoring wells (PH1, PH2, PH3, PH4, PH5) and four seawater intrusion monitoring wells (GG1, GG2, YI1, YI2). Six of the monitored wells showed groundwater level decreases of 9–81 cm and two of them exhibited a recovery to the previous level within three days while the remaining wells did not. And six monitoring wells showed EC changes to the earthquake with -1,274–161 μS/cm. In addition, three wells showed discernible groundwater temperature fluctuations of -0.2–0.3oC. Here, we found the magnitude of groundwater level change is decreasing with distance of the monitoring wells from the epicenter. Some detailed analyses on the relationship between the responses and a variety of hydrogeological parameters deserve a further study. This work was supported by the Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy (No. 20183010111860) and by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2015R1A4A1041105). [ABSTRACT FROM AUTHOR]

Seasonal fluctuation in groundwater level (below the ground surface) and water quality variables are mainly attributed to climatic conditions, soil characteristic, drainage method, and management practices. Groundwater degradations and high nitrate values have taken considerable attention in the Republic of Korea. Water management practices needs to be based on results of monitoring of groundwater level and water quality variables. We studied spatial variations based on temporal fluctuations of groundwater level (GWL), and water quality parameters including pH, electrical conductivity (EC), and nitrate (NO3). These contents were monitored from year 2011 to 2014 in 70 groundwater wells of an agricultural region in Korea. The monitoring of contents was done in field and collected data after laboratory analysis, was analyzed by using geostatistical modeling and mapping techniques. Seasonal variations in GWL during the period of four years of monitoring were ranged 2.91–5.17 m and 2.80–4.08 m in wet and dry seasons, respectively. The variations in pH value for the same period ranged 6.55–7.50 and 6.69–7.82 in wet and dry seasons, respectively. The fluctuations in EC values ranged 125–604 μg/cm and 80–272 μg/cm in wet and dry seasons, respectively. The values for NO3 in groundwater ranged 12.87–34.40 mg/L and 9.46–38.80 mg/L during the wet and dry seasons. The GWL shows strong spatial dependence, while pH and EC show strong to weak spatial dependence. The groundwater NO3 shows partial spatial dependence with decreased values in 2014 compared to the values in 2011. This finding is attributed to improved agricultural practices and change in land use pattern from white radish and cabbage to orchards and ginseng fields. This work was supported by the National Research Foundation of Korea (NRF) grant, funded by the Korean government (MSIT) (NRF-2015R1A4A1041105) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2018R1D1A1B07047200). [ABSTRACT FROM AUTHOR]

Water is an essential element for all organism, including human. There are anaerobic organisms in nature, but no organisms hate water. As time goes on, the interest and need for such water management is increasing worldwide. Seawater is the most abundant on the Earth's water and accounts for more than 95% of the total. But this is the salty water that humans can not drink. So, even if most of the water is seawater, it is important to manage the fresh water that humans can drink. Uses in which water is used in human life are various such as agriculture and living water. Therefore, the purpose of this study is to contribute to the management of groundwater used in everyday life. Groundwater can be largely divided into quantity and water chemistry. Of these, interest in this study is related to water chemistry and is water temperature. Groundwater chemistry can be changed by temperature change. So, we want to predict changes in the future by analyzing past groundwater temperature changes. Box plot was used as the study method. This makes it is easy to see the yearly change visually. In this box, displays 25% to 75% of the total data distribution. Also, values outside the minimum (25% – 1.5 × IQR) and maximum (75% + 1.5 × IQR) range are designated and excluded as outliers. The line in the box represents the median, which is not necessarily located in the middle of the box. This study used water chemistry data from 2011 to 2015. The result of this study suggests that groundwater temperatures have risen over the past five years, and that this can increase in the future. This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2015R1A4A1041105). [ABSTRACT FROM AUTHOR]

Microplastic (MPs) contamination in groundwater has received massive attention since plastic waste has been released directly into the environment. This study investigates MPs contamination in groundwater on the Jeju volcanic Island, Korea. To the best of our knowledge, this is the first study to identify MPs in groundwater from volcanic islands. A total of 21 sites were sampled for groundwater wells and springs in July and September (2021). Sampling was performed without cross-contamination through quality assurance and quality control. The results showed that MPs abundance ranged from 0.006 to 0.192 particles/L in groundwater samples. Additionally, MPs were detected in deep groundwater wells where the groundwater level was 143 m below ground surface. Eight MPs polymer types, including polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, polyamide, acrylonitrile butadiene styrene, and polyurethane, were detected using Micro-Fourier Transform Infrared Spectroscopy (μ-FT-IR). Most of the detected MPs size ranged from 20 to 100 μm, accounting for 95% of the total. Fragments and fiber shaped MPs were detected, with the majority of them being fragmented in groundwater samples. The concentrations of MPs and major ions in groundwater showed a positive correlation. A negative correlation was observed between MPs concentration and topographic elevation (r = −0.59, p = 0.01). The source of MPs contamination is most likely attributed to agricultural activities, such as plastic mulching and greenhouses, which account for most of the land use in the study area. In this study, MPs entered the aquifer through the soil at the surface and seeped through cracks in fractured rock on basalt with sealed groundwater wells. This study takes 500 L of samples to prevent sample bias, reveal plastic contamination in groundwater, and indicating the characteristics and sources of contaminated plastics. [Display omitted] • Most MPs detected in groundwater were smaller than 50 μm. • Eight polymers were identified, with PP and PE being dominant types in groundwater. • Predominant shapes of MPs in groundwater were fragments. • MPs abundance and groundwater levels have a negative correlation. [ABSTRACT FROM AUTHOR]

Objectives To estimate the loss in quality-adjusted life-years (QALYs) in Korean adults due to 13 noncommunicable diseases (NCDs) in 2010 and predict changes in QALY loss through to the year 2040. Methods Thirteen NCDs (hypertension, diabetes mellitus, hyperlipidemia, stroke, myocardial infarction, angina, arthritis, osteoporosis, asthma, allergic rhinitis, atopic dermatitis, cataract, and depression) were selected from the Korean Community Health Survey 2010. The EuroQol five-dimensional questionnaire index from the Korean Community Health Survey 2010 and the Korean valuation set were used to estimate utility weights according to sex, age, and disease. Morbidity data were also obtained from the Korean Community Health Survey 2010. Mortality data according to disease and life expectancy were retrieved from the Korean Statistical Information Service. To predict future QALY loss, future population projection data from the Korean Statistical Information Service were used as substitutes for 2010 population size. Results Among the assessed 13 NCDs, the largest total QALY loss was for hypertension (513,113 QALYs; units are omitted hereafter), followed by arthritis (509,317) and stroke (431,049). The largest QALY loss due to mortality was stroke (306,733), whereas the largest QALY loss due to morbidity was arthritis (502,513). By applying the middle estimate of future population, the largest increase in total QALY loss between 2010 and 2040 was for hypertension (840,582), followed by stroke (719,076) and diabetes mellitus (474,607). Conclusions Hypertension, arthritis, and stroke are important in terms of total QALY loss, which will continuous to increase because of aging. These results could be used to develop cost-effective interventions that reduce the burden of NCDs. [ABSTRACT FROM AUTHOR]

The international lack of water is publicly known. Over time, interest in groundwater and surface waters has increased for domestic use as drinking water and agricultural water. Due to the impacts of climate change, floods, landslides, droughts and other disasters related to water are becoming more and more important, and the need for water resources planning and management is emphasized. This study was aimed to assess the trend of groundwater quality in Korea. We also investigated the main drivers behind the trend and are attributed to rock-type and land use. Data was collected for 10 years from groundwater quality monitoring in Korea. Twelve water quality parameters were analyzed year by year. The collected data was statistically analyzed using a nonparametric method (Mann-Kendall trend test, M-K trend test). In addition, normality was analyzed by histogram (K-S test / Kolmogorov-Smirnov test or S-W test / Shapiro-Wilk test) and box plot. The Mann-Kendall trend test used the data for more than 5 years to identify the trends. The results were displayed on the map of the whole country, showing trends by regions. All of the water quality parameters were not statistically normal as a result of verifying the normality of the whole data through P-value in the histogram. Also, it was not normally distributed as a result of verifying the normality of yearly collected data through box plot. As a result of testing the normality of the M-K trend test using P-value, the T and HCO3- increased nationwide, and the pH, Eh and NO3- decreased nationwide. While, Cl-, Mg2+ and SO42- increased in the central area and decreased in the south. Potassium decreased markedly in the south, and EC and Ca2+ showed no regional trends. The reason for the regional difference was thought to be the influence of the rock type of the area where the irrigation had been installed, and it was affected by the land use. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2015R1A4A1041105). [ABSTRACT FROM AUTHOR]

Abstract: Hydrogeologic and hydrochemical data for subway tunnel seepage waters in Seoul (Republic of Korea) were examined to understand the effect of underground tunnels on the degradation of urban groundwater. A very large quantity of groundwater (up to 63 million m3 year−1) is discharged into subway tunnels with a total length of 287 km, resulting in a significant drop of the local groundwater table and the abandonment of groundwater wells. For the tunnel seepage water samples (n =72) collected from 43 subway stations, at least one parameter among pathogenic microbes (total coliform, heterotrophic bacteria), dissolved Mn and Fe, NH4 +, NO3 −, turbidity, and color exceeded the Korean Drinking Water Standards. Locally, tunnel seepage water was enriched in dissolved Mn (avg. 0.70 mg L−1, max. 5.58 mg L−1), in addition to dissolved Fe, NH4 +, and pathogenic microbes, likely due to significant inflow of sewage water from broken or leaking sewer pipes. Geochemical modeling of redox reactions was conducted to simulate the characteristic hydrochemistry of subway tunnel seepage. The results show that variations in the reducing conditions occur in urban groundwater, dependent upon the amount of organic matter-rich municipal sewage contaminating the aquifer. The organic matter facilitates the reduction and dissolution of Mn- and Fe-bearing solids in aquifers and/or tunnel construction materials, resulting in the successive increase of dissolved Mn and Fe. The present study clearly demonstrates that locally significant deterioration of urban groundwater is caused by a series of interlinked hydrogeologic and hydrochemical changes induced by underground tunnels. [Copyright &y& Elsevier]