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[Display omitted] • Groundwater Deficit (GWD) highlights delayed response to precipitation decline. • GWD characterizes and quantifies groundwater drought, including spatial extent. • GWD identifies thirteen drought events over a two-decade span in South Korea. Although South Korea is frequently subjected to monsoons, the shortage of summer monsoons and relatively dry spring and winter seasons cause droughts in the Korean Peninsula. Since the late 1960s, severe droughts in South Korea have encouraged extensive groundwater development for agricultural and economic growth. Therefore, identifying and estimating the impact of droughts on the country's groundwater resources is crucial for establishing policies and regulations on groundwater exploitation and recharge. Current drought management of the country relies on a meteorological drought index. However, these estimates lack a comprehensive understanding of absolute drought severity and propagation. This study aims to develop a quantitative method for calculating the frequency and severity of groundwater droughts based on the Groundwater Deficit (GWD) derived from NASA's Gravity Recovery and Climate Experiment (GRACE) mission data. The estimated annual GWD in mass over the country ranges from -0.07 km3 to 0.04 km3, with a trend in the mass of -1.60×10−3 km3/year from 2002 to 2021. Thirteen groundwater drought events were identified based on GWD. Among those, the highest drought severities recorded in 2015 and 2019 were -34.27 km3 months and -55.38 km3 months, respectively. Monthly deficits define the quantity of water required to restore normal groundwater storage conditions. Hence, the minimum and average days to recover from groundwater droughts were estimated based on the strength of the storage-based approaches. The GWD approach aligns with meteorological drought databases with a time lag. It illustrates the transition from meteorological drought to groundwater drought, along with their onset, cessation, propagation, instantaneous severity, and peak magnitude. [ABSTRACT FROM AUTHOR]

The chemical and isotopic compositions of groundwater and stream water in the Haean basin, Korea, which have been intensively used for agricultural irrigation, were examined. The field parameters and chemical compositions were typical of relatively uncontaminated waters, except for the agricultural impact. The low EC levels indicated that the waters had not experienced any significant geochemical processes such as water-rock interaction and evaporation. The very similar chemical compositions and ionic ratios were also indicative of fast circulation and good hydraulic connection. The oxygen and hydrogen isotopic compositions of most of the samples in wet and dry seasons showed very similar range which indicated a single source for both waters without any significant geochemical alteration. However, in the wet season, evaporation trends were observed in some groundwaters because of inflow of irrigation return flow from a rice paddy field. The isotopes of both waters were affected by the altitude and amount of precipitation. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate groundwater conditions in the four greatest megacities (Seoul, Busan, Daegu, and Incheon) of Korea using 5-year (2006-2010) monitoring data obtained from the Korean National Groundwater Monitoring Stations. With decreasing of groundwater draft, groundwater levels for the 5-year period were not substantially decreasing but they responded differently to outer stress like rainfall according to degree of urbanization or pavement of surrounding areas. However, groundwater and air temperatures were gradually increasing due to the widespread climate change. Coastal groundwaters (Seoul, Busan, and Incheon) have suffered from seawater intrusion, which can be aggravated by sea level rise in the future. Some monitoring stations of the megacities observed a drastic decrease of groundwater level for a specific period and the marked increasing of electrical conductivity; thus, detailed investigations revealing the causes and appropriate mitigation measures are required. Urban groundwater did not uniformly respond to outer anthropogenic and natural stresses because a variety of human interventions are differently involved. [ABSTRACT FROM AUTHOR]

Pollution of groundwater by seawater intrusion poses a threat to sustainable agriculture in the coastal areas of Korea. Therefore, seawater intrusion monitoring stations were installed in eastern, western, and southern coastal areas and have been operated since 1998. In this study, groundwater chemistry data obtained from the seawater intrusion monitoring stations during the period from 2007 to 2009 were analyzed and evaluated. Groundwater was classified into fresh (<1,500 μS/cm), brackish (1,500-3,000 μS/cm), and saline (>3,000 μS/cm) according to EC levels. Among groundwater samples ( n = 233), 56, 7, and 37% were classified as the fresh, brackish, and saline, respectively. The major dissolved components of the brackish and saline groundwaters were enriched compared with those of the fresh groundwater. The enrichment of Na and Cl was especially noticeable due to seawater intrusion. Thus, the brackish and saline groundwaters were classified as Ca-Cl and Na-Cl types, while the fresh groundwater was classified as Na-HCO and Ca-HCO types. The groundwater included in the Na-Cl types indicated the effects of seawater mixing. Ca, Mg, Na, K, SO, and Br showed good correlations with Cl of over r = 0.624. Of these components, the strong correlations of Mg, SO, and Br with Cl ( r ≥ 0.823) indicated a distinct mixing between fresh groundwater and seawater. The Ca/Cl and HCO/Cl ratios of the groundwaters gradually decreased and approached those of seawater. The Mg/Cl, Na/Cl, K/Cl, SO/Cl, and Br/Cl ratios of the groundwaters gradually decreased, and were similar to or lower than those of seawater, indicating that Mg, Na, K, SO, and Br, as well as Cl in the saline groundwater can be enriched by seawater mixing, while Ca and HCO are mainly released by weathering processes. The influence of seawater intrusion was evaluated using threshold values of Cl and Br, which were estimated as 80.5 and 0.54 mg/L, respectively. According to these criteria, 41-50% of the groundwaters were affected by seawater mixing. [ABSTRACT FROM AUTHOR]

Summary: Groundwater is nearly the sole source for freshwater supply on Jeju volcanic island because there are no perennial streams and rivers. Rain harvesting and subsequent artificial recharging have been conducted to meet growing freshwater demand in the island. We performed sequential samplings of harvested rainwater prior to the artificial injection in summer of 2008 at an artificial recharge site of western Jeju. Field measurements and chemical analyses of 313 rainwater samples revealed that there was a variation in chemical composition but the Na+K+SO4 +Cl type was dominant. Predominance of Na and Cl was likely to be from sea salts while substantial amount of SO4, NO3 , and NH4 is attributed to anthropogenic air pollution. The enrichment factors of SO4, HCO3, K, Mg, and Ca suggested that their non-marine contribution ranges from 75.4% to 99.98%. However, the sea salt contributed substantially to Cl concentration up to 73.5%. Most of the rainwater parameters generally decreased with time and they were generally stabilized after 20min, which is an effect of the first flush and thus some diversion (rerouting) is required for suitable artificial injection of the harvest rainwater in this study area. [ABSTRACT FROM AUTHOR]

Abstract: Characteristics of hydrologic time series data obtained from an undersea LPG (butane and propane) storage cavern were analyzed in time and frequency domains. The analyzed data included cavern seepage rates, cavern operating pressures (gas pressures), water levels of monitoring boreholes in and around the cavern, surrounding tidal levels and site precipitations of long and short periods. The seepage rates showed annual periodic behaviors, which were related to seasonal LPG use pattern. The gas operating pressures were the most dominant controlling factor for the seepage rates. The tidal level revealed an apparent negative cross-correlation with the seepage rate. However, the long-term close correlation between the tidal level and the seepage rate might be attributed to coincident concurrence of the seasonal LPG use and the tidal level variation. The water levels of the monitoring boreholes showed significantly different auto-correlations and spectral densities with locations. The water levels near the butane cavern exhibited high memory effects and low cross-correlations with the tidal level while those of the propane cavern exhibited short memory effects and relatively higher cross-correlations with the tidal level. The difference in all the hydrologic responses (seepage and water level) of the two caverns to the outer stresses such as precipitation, gas operating pressure and tidal level, can be mostly related to the hydrogeologic stratification surrounding the caverns. The low permeable silty clay layer is very thick above the butane cavern while it is very thin about the propane, such that greater hydraulic connection to the overlying sea could be expected. [Copyright &y& Elsevier]

Abstract: In Korea, ground source heat pumps (GSHP) have been gaining popularity for space heating and cooling. Because there are few sources of high-temperature geothermal energy in the country, public baths (25–40°C) and geothermal heat pumps (∼15°C) using low-temperature groundwater or ground are the most dominant direct geothermal uses. The Promotion Law of the New and Renewable Energy Development, Use and Dissemination, enacted in 2004, imposed an obligatory installation of space heating and cooling systems using new and renewable energy sources including geothermal energy for newly constructed public buildings (more than 5% of total construction cost). Between 2004 and 2007, ground source heat pump systems occupied about 60% of the total public installation of new and renewable energy equipment. Starting with 35.2kW of two facilities in 2000, systems with the capacity of over 127.1MWt have been installed in 551 buildings (facilities) as of August 2008. The vertical closed heat pump system (closed loop) and the groundwater heat pump system (standing column well type; SCW) occupied 65.1% and 29.3%, respectively, among the total GSHP systems installed. The depth of the vertical loops ranged between 65 and 250m (average 159m) and the well depth of the SCW system ranged between 150 and 600m (average 391m). The number of geothermal energy companies, installing the GSHP systems, that are officially registered in the relevant authority increased from 5 in 2000 to 397 in July 2008. This paper presents details of the current status of ground source heat pumps in Korea. [Copyright &y& Elsevier]

Soil and groundwater at a rail rolling stock workshop in a metropolitan city were contaminated with heavy metals including Pb, Cu and Cd. Prior to remedial design, a variety of field and laboratory investigations were conducted to characterize hydrogeologic conditions and to examine levels and extents of the contamination. The hydrogeology of the studied site near the Han River is comprised of reclamation soil, alluvial deposit, weathered layer and soft rock. The alluvial deposit consists of sand, clay and silt, sandy gravel and its spatial distribution is very heterogeneous. Most groundwater occurs in the sandy gravel layer and groundwater within the site generally flows into two directions, north and west. Mean hydraulic gradients were 0.082-0.0129 and hydraulic conductivities of the main aquifer range between 5.42 × 10- 2 and 2.18 × 10- 6 cm/sec. Average linear velocity of groundwater was calculated as 15-24 m/year. The groundwater levels were mostly affected by atmospheric pressure change, which reflected confined characteristics of the aquifer system. High EC and low DO indicated anthropogenic contamination of the site. The Pb and Cu contamination of soil exceeding the Korean soil standards were mainly observed at locomotive inspection, rest train wash and scrap iron dump areas. Substantial contamination of groundwater with Cd was also detected at different location. [ABSTRACT FROM AUTHOR]

Seawater intrusion is a problem in the coastal areas of Korea. Most productive agricultural fields are in the western and southern coastal areas of the country where irrigation predominantly relies on groundwater. Seawater intrusion has affected agricultural productivity. To evaluate progressive encroachment of saline water, the Korean government established a seawater intrusion monitoring well network, especially in the western and southern part of the peninsula. Automatic water levels and EC monitoring and periodic chemical analysis of groundwater help track salinization. Salinization of fresh groundwater is highly associated with groundwater withdrawal. A large proportion of the groundwaters are classified as Na–Cl and Ca–Cl types. The Na–Cl types represent effects of seawater intrusion. The highest EC level was over 1.6 km inland and high Cl values were observed up to 1.2 km inland. Lower ratios of Na/Cl and SO4/Cl than seawater values indicate the seawater encroachment. A linear relation between Na and Cl represents simple mixing of the fresh groundwater with the seawater. The saline Na–Cl typed groundwaters showed Br/Cl ratios similar to or less than seawater values. The Ca–HCO3 type groundwaters had the highest Br/Cl ratios. Substantial proportions of the groundwaters showed potential for salinity and should be better managed for sustainable agriculture. [ABSTRACT FROM AUTHOR]

To delineate spatial extent of seawater intrusion in a small experimental watershed in the coastal area of Byunsan, Korea, electrical resistivity surveys with some evaluation core drillings and chemical analysis of groundwaters were conducted. The vertical electrical sounding (VES) method was applied, which is useful to identify variations in electrical characteristics of layered aquifers. The drilling logs identified a three-layered subsurface including reclamation soil, weathered layer and relatively fresh sedimentary bedrock. The upper two layers are the main water-bearing units in this area. A total of 30 electrical sounding curves corresponded mostly to the H type and they were further divided into three classes: highly conductive, intermediate, and low conductive, according to the observed resistivity values of the most conductive weathered layer. In addition, groundwater samples from 15 shallow monitoring wells were analyzed and thus grouped into two types based on HCO3/Cl and Ca/Na molar ratios with TDS levels, which differentiated groundwaters affected by seawater intrusion from those not or less affected. According to relationships between the three classes of the sounding curves and groundwater chemistry, locations of the monitoring wells with low HCO3/Cl and Ca/Na ionic ratios coincided with the area showing the highly conductive type curve, while those with the high ratios corresponded to the area showing low conductive curve type. Both the low electrical resistivity and the low ionic ratios indicated effects of seawater intrusion. From this study, it was demonstrated that the VES would be useful to delineate seawater intrusion in coastal areas. [ABSTRACT FROM AUTHOR]

Abstract: The rockfill dam of this study has a clay core, filter zone, and sandy gravel shell, and it is located in the Nakdong River basin in Korea. Filling the reservoir began in August 1994 and it was full by April 1998. When the reservoir level was approximately 150 m, three settlement holes were found in the dam crest. To determine possible seepage paths and potential damaged areas within the rockfill dam, 15 tracer tests were performed during two periods. During the two test periods, six and nine tracer tests were conducted when the average water levels of the reservoir were 145 m and 142 m, respectively. Rhodamine WT (RWT) and bromide ion were used as tracers. For each test, 1800 to 4000 L of tracer solution were injected into the riprap for about 5 h. The 15 injection points were uniformly distributed from the right to left sides of the embankment and the two tracers were injected alternately. Tracer concentrations were monitored at 26 observation wells, which were divided into four groups by their geographical positions: right side of the crest, left side of the crest, right side of the dam toe, and left side of the dam toe. For each tracer test, more than 30 water samples were taken during a period of 96 h at each observation well. Based the breakthrough curves obtained from the sequential tracer tests, it was inferred that the most probable seepage paths and potential damaged area were in the left side of the crest (tongue wing zone) and, to a lesser extent, in the right side of the dam abutment. [Copyright &y& Elsevier]

This study evaluated variations in heavy metal contamination of stream waters and groundwaters affected by an abandoned lead–zinc mine, where a rockfill dam for water storage will be built 11 km downstream. For these purposes, a total of 10 rounds of stream and groundwater samplings and subsequent chemical analyses were performed during 2002–2003. Results of an exploratory investigation of stream waters in 2000 indicated substantial contamination with heavy metals including zinc (Zn), iron (Fe) and arsenic (As) for at least 6 km downstream from the mine. Stream waters near the mine showed metal contamination as high as arsenic (As) 8,923 μg L−1, copper (Cu) 616 μg L−1, cadmium (Cd) 223 μg L−1 and lead (Pb) 10,590 μg L−1, which greatly exceeded the Korean stream water guidelines. Remediation focused on the mine tailing piles largely improved the stream water qualities. However, there have still been quality problems for the waters containing relatively high concentrations of As (6–174 μg L−1), Cd (1–46 μg L−1) and Pb (2–26 μg L−1). Rainfall infiltration into the mine tailing piles resulted in an increase of heavy metals in the stream waters due to direct discharge of waste effluent, while dilution of the contaminated stream waters improved the water quality due to mixing with metal free rain waters. Levels of As, Cu and chromium (Cr) largely decreased after heavy rain but that of Pb was rather elevated. The stream waters were characterized by high concentrations of calcium (Ca) and sulfate (SO4), which were derived from dissolution and leaching of carbonate and sulfide minerals. It was observed that the proportions of Ca and SO4 increased while those of bicarbonate (HCO3) and sodium and potassium (Na+K) decreased after a light rainfall event. Most interestingly, the reverse was generally detected for the groundwaters. The zinc, being the metal mined, was the most dominant heavy metal in the groundwaters (1758–10,550 μg L−1) near the mine, which far exceeded the Korean standard of 1000 μg L−1 for drinking water. The decreases in the heavy metals contents in the groundwaters associated with reduced rainfall were quite different from the increases observed for the stream waters, which is not clearly understood at this time and warrants further investigation. [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]

Summary: The Korean Ministry of Construction and Transportation (MOCT) and the Korean Ministry of Environment (MOE) manage the National Groundwater Monitoring Stations (NGMS) and the Groundwater Quality Monitoring Stations (GQMS) under Article 17 of the Groundwater Act. Under the same legislation, local government will install or designate an additional 10,000 monitoring wells as Subsidiary Groundwater Monitoring Stations (SGMS) by 2011. However, a standard for the installation and management of the SGMSs has not yet been developed. This study focuses on the development of a model for the determination of optimal monitoring frequencies during the manual measurement of the SGMSs. The groundwater level time series for the 81 deep and shallow monitoring wells making up the NGMSs were analyzed using an AR(p) model, and a harmonic series model was then made for the determination of groundwater level sampling frequency in the SGMSs. The result showed that the average sampling frequency necessary for groundwater level monitoring is about once every 8.9 days. Moreover, it indicates that water level sampling needs to be performed more frequently in steeply inclined sites, deep wells, and in monitoring wells belonging to an AR(2) rather than an AR(1) model. [Copyright &y& Elsevier]

Two new biphenylquinolizidine alkaloids, 5-epi-dihydrolyfoline (1) and its stereoisomer, dihydrolyfoline (2), along with lagerine (3) were isolated from the aerial parts of Lagerstroemia indica. The structures of compounds 1-3 were elucidated by extensive spectroscopic techniques.

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.

This paper provides an overview of the Korean Burden of Disease (KBoD) study, which was the first such study to assess the national burden of disease using disability-adjusted life years (DALYs) in an advanced Asian country. The KBoD study generally followed the approach utilized in the original Global Burden of Disease study (GBD), with the exception of the disease classification and epidemiological data estimation methods used, and the relative weightings of disabilities. The results of the present study reveal that the burden of disease per 100,000 of the Korean population originates primarily from; cancer (1,525 Person Years, PYs), cardiovascular disease (1,492 PYs), digestive disease (1,140 PYs), diabetes mellitus (990 PYs), and certain neuro-psychiatric conditions (883 PYs). These results are largely consistent with those of developed countries, but also represent uniquely Korean characteristics.

Objectives: As the disabled have higher prevalence rates and earlier onsets of chronic diseases than the non-disabled, their participation in mass screening is important for the early detection and intervention of chronic diseases. Nevertheless, in Korea, the disabled have lower participation rates in mass screening services than the non-disabled. The purpose of the study was to find determinants for the participation in the National Health Insurance (NHI) mass screening program among the disabled., Methods: In this study, the NHI mass screening data of 423,076 disabled people, which were identified using the National Disability Registry (2003), were analyzed. Of the factors affecting the participation rates in mass screenings, the following variables were included for the analysis: socioeconomic stati, such as sex, age, category of health insurance program, region and income; disability characteristics, such as disability type, and severity. A multiple logistic regression analysis was used to evaluate the association between the participation rates, disability characteristics variables and demographic variables., Results: The participation rate in mass screening of the disabled was 41.3%, but was lower in females, an age of more than 70 years, self-employed and for those with an average monthly insurance premium over 133,500 Won and in metropolitan regions. The participation rate was 1.31 times lower in females than males (95% CI=1.29-1.33); 3.50 times lower in the elderly (more than 70 years) than the younger (95% CI=3.33-3.67); 1.43 times lower in those who live in metropolitan areas (95% CI=1.40-1.46); 2.59 times lower for those in a health insurance program for the self-employed than for employees (95% CI=2.56-2.63); 1.19 times lower for the higher income (more than 133,500) than the lower income group (4,400-22,000) for the average monthly insurance premium (95% CI=1.15-1.23); 2.04 times lower for those with brain palsy and stroke disabilities than with auditory impairments (95% CI= 1.97-2.11) and 3.27 times for those with severe compared to mild disabilities (95% CI=3.15-3.40)., Conclusions: The disabled with high severity, and locomotive and communication disabilities have lower participation rates in mass screening services in Korea.

Objectives: This study estimated the burden of disease especially caused by psychiatric disorders in Korea by using DALY, a composite indicator that was recently developed by the Global Burden of Disease study group., Methods: First, 11 of the major psychiatric disorders in Korea were selected based on the ICD-10. Second, the burden of disease due to premature death was estimated by using YLLs (years of life lost due to premature death). Third, for the calculation of the YLD (years lived with disability), the following parameters were estimated in the formula: the incidence rate, the prevalence rate and the disability weight of each psychiatric disorder. Last, we estimated the DALY of the psychiatric disorders by adding the YLLs and YLDs., Results: The burden of psychiatric disorder per 100,000 people was attributed mainly to unipolar major depression (1,278 person-years), schizophrenia (638 person-years) and alcohol use disorder (287 person-years). For males, schizophrenia (596 person-years) and alcohol use disorder (491 person-years) caused the highest burden. For females, unipolar major depression (1,749 person-years) and schizophrenia (680 person-years) cause the highest burden. As analyzed by gender and age group, alcohol use disorder causes a higher burden than schizophrenia in men aged 40 years and older. For females, unipolar major depression causes the highest burden in all age groups., Conclusions: We found that each of the psychiatric disorders that cause the highest burden is different according to gender and age group. This study's results can provide a rational basis to plan a national health policy regarding the burden of disease caused by psychiatric disorders.

Objectives: The biosafety level (BSL) practiced in microbiology laboratories in Korea according to the laboratory biosafety manual published by the World Health Organization (WHO) was evaluated using the data obtained by a survey., Methods: Under the advise of Clinical Laboratory Physicians, 144 types of microorganisms were screened based on the guidelines of biosafety in microbiological and biomedical laboratories published by the US Center for Disease Control and Prevention and classified into 1-4 risk groups. A questionnaire containing 21 questions in 5 areas was developed using the biosafety manual by published WHO. Of the 1,876 different organizations sent the survey, 563 responded to the survey (response rate: 30.0%). The species of microoganisms handled by as well as the biosafety level in microbiology laboratories were analyzed., Results: There were 123 species of microorganisms handled in microbiology labs in Korea. The BSL required in 512 microbiology labs was answered by the survey responders as the first grade in 33 labs (6.4%), 2nd in 437 (85.4%), 3rd in 42 (8.2%), and 4th in none. The average number of items satisfied was 12.2, showing only a 57.9% satisfactory rate and normal distribution., Conclusions: The state of overall observance of BSL in most microbiology labs of Korea was evaluated as lagging compared with the standard set up by WHO. Therefore, the Korean government need to produce and distribute a biosafety manual in microbiology laboratories and make efforts to prevent this threat through measures such as training in biosafety in microbiology labs.

Objectives: This study estimated the burden of disease due to high alcohol consumption using DALY, a composite indicator recently developed by the Global Burden of Disease study group. The results were analyzed by age and sex., Methods: Firstly, high alcohol consumption-related diseases, and their relative risk (RR), were selected. Secondly, population attributable fractions (PAFs) were computed using formulae, including the relative risk (RR) and prevalence of exposure (Pe). Thirdly, the DALYs of high alcohol consumption-related diseases were estimated. Lastly, the attributable burdens of diseases due to high alcohol consumption wereconcluded as being the sum of the products that multiplied the DALYs of high alcohol consumption-related diseases by their population attributable fraction (PAF)., Results: The burden of high alcohol consumption in Korea was 2992.3 person years (PYs) per 100,000 persons in men, and 1426.6 in women. For men, the high alcohol consumption-induced diseases with the five biggest burdens were liver cirrhosis, hypertensive disease, liver cancer, cerebral infarction and intracerebral hemorrhage. For women, these were cerebral infarction, intracerebral hemorrhage, hypertensive disease, liver cirrhosis and liver cancer., Conclusion: This study highlighted the attributable fraction of diseases due to exposure to high alcohol consumption, by quantifying the results of exposure to risk factors. Therefore, it is now possible to assess interventions for risk factors in quantifiable terms in each population. Finally, measuring the risk factor burdens was expected to contribute to priority setting and effective resource allocation in public health policy.

Objective: To evaluate the relationship between cytosine-adenine (CA) polymorphism of the calcitonin gene, serum calcitonin levels, bone mineral density (BMD) and bone responsiveness to hormone therapy (HT)., Design: Calcitonin (CA) polymorphism, serum calcitonin, and BMD at the lumbar spine and proximal femur were determined in 430 postmenopausal Korean women. In all, 181 women were treated with sequential HT for 2 years., Results: Four major calcitonin alleles were present with a frequency greater than 5%: 122 base pair (bp) 61.3%, 108 bp 25.1%, 110 bp 7.0%, and 124 bp 6.2%. There were no differences in the BMD at the lumbar spine and proximal femur in postmenopausal women with zero, one, or two copies of major alleles. Serum calcitonin levels in women with two copies of the 108 bp allele were significantly higher than those in women with zero or one copy of the 108 bp allele. The annual rate of positive change of BMD at the femoral neck after HT was significantly higher in women homozygous for the 108 bp allele than in women with zero or one copy of the 108 bp allele, but the number of copies of the major calcitonin alleles was not significantly associated with HT-responsiveness., Conclusion: The calcitonin (CA) polymorphism is one of the genetic factors that may affect BMD changes at the femoral neck after HT in Korean women.

Aim: A prospective, non-comparative study was conducted to evaluate the efficacy and efficiency of a starting dose of 100 IU recombinant follicle stimulating hormone (rhFSH, Puregon) in women undergoing ovarian stimulation prior to in vitro fertilization (IVF)., Methods: A total of 40 women were down-regulated with gonadotropin releasing hormone agonist (long protocol), then treated with a fixed dose of 100 IU rhFSH for the first 4 days, and the dose of gonadotropin administration was adjusted according to patient's response thereafter. A maximum number of 3 embryos were transferred in 32 patients., Results: Nine patients were treated with intracytoplasmic sperm injection, and 24 with conventional IVF. The duration of stimulation was 10.8 +/- 1.8 days, serum estradiol concentration on human chorionic gonadotropin day was 1693.0 +/- 1651.2 pg/mL, and 1480 +/- 450 IU rhFSH was used. A mean number of 8.4 +/- 5.7 oocytes were retrieved, 4.9 +/- 4.3 embryos obtained, 2.4 +/- 0.9 embryos transferred, and 3.5 +/- 3.2 embryos cryopreserved. The proportion of mature oocytes was 71.6%, and the fertilization rate was 86.4%. Clinical pregnancy was achieved in 8 patients (25.0%), and all of these pregnancies are ongoing or delivered. There were 3 cases of twin gestations (37.5%). The implantation rate was 13.1% (11/84). There was one case of moderate ovarian hyperstimulation syndrome, however, the patient recovered within 7 days without any complications., Conclusion: The starting dose of 100 IU rhFSH has a good safety profile, and is adequate in controlled ovarian hyperstimulation for IVF with a small amount of gonadotropin administered.

This study focused on evaluating and quantifying the potential of natural attenuation of groundwater at a petroleum-contaminated site in an industrial area of a satellite city of Seoul, Korea. Groundwater at the study site was contaminated with toluene, ethylbenzene and xylene (TEX). Eight rounds of groundwater sampling and subsequent chemical analyses were performed over a period of 3 years. The groundwater quality data suggests that TEX concentrations at this site have been decreasing with time and that the TEX plume is at a quasi-steady state. Trend analysis, changes in mass flux and plume area also confirmed that the TEX plume has reached a quasi-steady state. The proportion of the total attenuation attributable to biodegredation has decreased over the monitoring period while contribution of other attenuating processes, such as dilution or dispersion, has increased. Based on the calculated attenuation rates, it would take more than 20 years to clean up the site by natural attenuation alone.

Objective: The objective of this study was to test the hypothesis that the cytosine-adenine polymorphism in the insulin-like growth factor-I gene is associated with serum insulin-like growth factor-I levels and bone mineral density., Study Design: The insulin-like growth factor-I cytosine-adenine polymorphism was analyzed in 300 postmenopausal Korean women. Serum insulin-like growth factor-I, bone alkaline phosphatase, and carboxy-terminal cross-linking telopeptide of type I collagen were measured by immunoradiometric assay and enzyme-linked immunosorbent assay. Bone mineral density at the lumbar spine and proximal femur was determined by dual energy radiograph absorptiometry., Results: Serum insulin-like growth factor-I and bone mineral density levels in women who were homozygous for a 194-base pair allele were significantly higher than those levels in the 194-base pair heterozygotes or women who did not possess the 194-base pair allele. A significantly decreased prevalence of the 194/194 genotype was observed in the combined group of women with osteopenia and osteoporosis, compared with normal women. No correlation between insulin-like growth factor-I genotypes and bone turnover markers was found., Conclusion: The insulin-like growth factor-I gene cytosine-adenine polymorphism relates with circulating insulin-like growth factor-I levels and bone mineral density at the lumbar spine and proximal femur.