• Journal of Soil and Groundwater Environment
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• v.29 no.1
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• pp.39-50
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• 2024

Slags from steel-making industry have been recycled at a target rate of 95% and most of them are recycled as media-contact type such as fill and cover materials in Korea. However, as they contain free phase CaO during their generation, they may not only expand and collapse upon contact with water, but high pH leachate and heavy metals leaching may occur. In this study, the Korean leaching procedure (KLP) and up-flow percolation test were performed for the samples collected from 17 steel-making production plants in Korea. The waste quality criteria were met in all tests, but pH of the samples was above 10. There are no regulations on the pH of leachate in most of the countries, however, Germany, Italy, and Australia have set a pH range of 10 to 13 for the leachates. Although slag leachate cannot be considered hazardous based only on its high pH, it is necessary to reduce the pH of leachate to minimize the impact on the surrounding environment. Furthermore, conflicting regulations on wastes handling and management in Korea created confusion on the types of wastes subject to recycling. Therefore, an appropriate management plan for steel-making slags needs to be established. To this end, this study attempted to provide a guideline for managing steel-making slag waste by considering international guidelines and current management practices in Korea.

• Progress in Medical Physics
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• v.9 no.4
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• pp.195-200
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• 1998

Purpose: When an elongated x-ray field is used for treating a patient, the equivalent- field method is commonly used for the output calculation. This study is intended for investigating potential factors such as, beam quality, field elongation ratio, and depth of measurement, which might effect on the applicability of the equivalent square technique for output calculation. The derivation of a 'rule of thumb' for the application criteria of the equivalent-field method is also aimed. Materials and Methods: Three x-ray beams, 4-, 6- and 10-MV, were employed for this study. Width of the rectangular field was ranged from 5-40 cm and the elongation ratio (length/width) 1:0 to 10:0. An elongation effect was measured in a water phantom at three different depths, dmax, 5-cm, and 10-cm. For an elongated field and its equivalent square field, the output factor was measured and the difference in the output factor were examined between two fields. Results and Discussions: As the elongation ratio increases, a larger discrepancy in outputs is observed between the elongated rectangular field and its corresponding equivalent square field. Output was measured larger for an elongated field than for its corresponding equivalent square field and the maximal difference over 10 % was found. The difference was found larger for the smaller field with the same elongation ratio. The effect of the beam quality and the depth of measurement on the output difference was minimal. Conclusion: Based on the study, there is criteria for the application of the method for output calculation. For the combination of long axis and elongation ratio whose relationship satisfies Elongation ratio < (0.48) (Long axis) - 0.5, the equivalent-field method is valid for output calculation within 2 % for the field whose long axis < 25-cm. For other combinations, instead of using the equivalent-field method, direct output measurement is recommended. This criteria can be applied for 4-10 MV x-ray beams up to 10-cm depth.

• Journal of Environmental Impact Assessment
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• v.21 no.3
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• pp.483-501
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• 2012

The purpose of this study was to apply a multi-metric model of Lentic Ecosystem Health Assessments(LEHA) for environmental impact assessments of Cheongpyung Reservoir during 2005 - 2006 and assessed the ecological model values. The ecosystem model of LEHA was composed of eleven metrics such as biological parameters($B_p$), physical parameters($P_p$), and chemical parameters($C_p$), and determined the rank of ecological health by the criteria. The variables of $B_p$ were metrics of % sensitive species($M_2$, NMS) and insectivore species($M_5$, % $I_n$), which decrease as the water quality degradates, and these metric values were low as 1.5% and 32.4%, respectively. In contrast, the proportions of tolerant species and omnivore species as the other $B_p$ parameters were 43% and 62%, respectively, which indicate a degradation and disturbance of the ecosystem. Riparian vegetation coverage($M_9$, % $V_c$) as a variable of $P_p$, were higher in the 2nd than 1st survey, and decreased toward the dam site from the headwaters. This was due to a habitat simplification(modifications) by frequent bottom dredging of sand and rocks. The variables of $C_p$ were two metrics of specific conductivity($M_{10}$, $C_I$) as an indicator of ionic contents(cations and anions) and the Trophic State Index(TSI) based on chlorophyll-a($M_{11}$, $TSI_{CHL}$) as an indicator of trophic state. These metric values of $C_p$ had high temporal variations, but low spatial variations on the main axis of the reservoir along with the ecological health of a good condition. The environmental impact assessments using the LEHA multi-metric model indicated that the model values of LEHA averaged 30.7 in 1st survey(fair - poor condition) vs. 28 in 2nd survey(poor condition), indicating a temporal variation of the ecological health. The model values of LEHA showed a minimum(28) in the lacustrine zone(S5) and ranged from 29 to 30 in the other locations sampled, indicating a low longitudinal variation. Overall, environmental impact assessments, based on LEHA model, suggest that chemical water quality conditions were in good, but biological conditions were disturbed due to habitat modifications by frequent dredgings in the system.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.91-97
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• 2005

This study was conducted to evaluate the influence of pollutant loads on the water quality in the Dongjin River area from January 2003 to December 2004. The average value of BOD and T-N showed the highest peak in Yongho, Dukcheon watershed among Dongjin River. Concentrations of BOD, T-N and T-P in Jeongeup watershed were 2.29 mg $L^{-1}$, 4.40 mg $L^{-1}$ and 0.27 mg $L^{-1}$, respectively. Concentration of BOD in Chilbo was 1.19 mg $L^{-1}$ which would be in the grade I according to water quality criteria by Ministry of Environment. The BOD level in Wonpeung and Sinpeung watershed ranged from 4.06 to 7.35 mg $L^{-1}$. The T-N effluent loads of non-point pollutants were high in Wonpeung, Gobu, Yongho Dukcheon, Jeongeup and Sinpeung watershed in order. The major sources of BOD, T-N and T-P effluent loads were Livestock. The T-P effluent load of non-point pollutant was 68 kg $day^{-1}$ in Wonpeung, 58 kg $day^{-1}$ in Yongho Dukcheon and 45 kg $day^{-1}$ Jeongeup watershed. The delivered loads of BOD was high in Gobucheon, while both T-N and T-P were high in Yongho Dukcheon. The delivery ratio of BOD and T-N at dry season was below 100% in all watershed of Dongjin River. The delivery ratio of T-N at raining season was high in Yongho Dukcheon and Chilbo watershed

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.145-156
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• 2006

The objective of this study was to evaluate biological health conditions and physicochemical status using multi-metric models at five sites of the Keum-Ho River during August 2004 and June 2005. The research approach was based on a qualitative habitat evaluation index (QHEI), index of biological integrity (IBI) using fish assemblage, and long-term chemical data (1995 ${\sim}$ 2004), which was obtained from the Ministry of Environment, Korea. For the biological health assessments, regional model of the IBI in Korea (An,2003), was applied for this study. Mean IBI in the river was 30 and varied from 23 to 48 depending on the sampling sites. The river health was judged to be "fair condition", according to the stream health criteria of US EPA (1993) and Barbour et al. (1999). According to the analysis of the chemical water quality data of the river, BOD, COD, conductivity, TP, TN, and TSS largely varied epending on the sampling sites, seasons and years. Variabilities of some parameters including BOD, COD, TP, TN, and conductivity were greater in the downstream than in the upstream reach. This phenomenon was evident in the dilution by the rain during the monsoon. This indicates that precipitation is a very important factor of the chemical variations of water quality. Community analyses showed that species diversity index was highest (H=0.78) in the site 1, while community dominance index was highest in the site 3, where Opsariichthys uncirostris largely dominated. In contrast, the proportions of omnivore and tolerant species were greater in the downstream reach, than in the upstream reach. Overall, this study suggests that some sites in the downstream reach may need to restore the aquatic ecosystem for better biological health.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.198-208
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• 2006

This research was to apply a multi-metric approach, so called the Index of Biological Integrity (IBI) as a tool for biological evaluations of water environments, to a wadable stream. For the study, we surveyed 5 sampling locations in Kap Stream during August 2004 ${\sim}$ September 2005. We also compared the biological data with long-term water quality data, obtained from the Ministry of Environment, Korea and physical habitat conditions based on the Quantitative Habitat Evaluation Index (QHEI). We used ten metric systems for the IBI model to evaluate biological stream health. Overall IBI values in Kap Stream averaged 24 (range: 20${\sim}$30, n=5), indicating a "fair ${\sim}$ poor" conditions according to the modified criteria of Karr (1981) and US EPA(1993). Exclusive of 4th survey, average IBI values at the upstream reach (S1 ${\sim}$ S3)and downstream reach (S4 ${\sim}$ S5) were 20 and 24, respectively. However, in 4th survey the averages were 21 and 20 in the upstream and downstream reaches, respectively. This difference was larger in the upstream than in the downstream because of physical condition disturbed during summer monsoon. Values of the QHEI varied from 75(fair condition) to 148 (good condition) and values of QHEI in the S3 were significantly (P=0.001, n=5) lower than other sites. Biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were greater by 3 ${\sim}$ 8 fold in the downstream than in the upstream reach. We believe that present IBI approach applied in this study may be used as a key tool to set up specific goals for restoration of Kap Stream.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.130-142
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• 2007

This study was to examine impacts of turbid water on fish community in the downstream of Yongdam Dam during the period from June to October 2006. For the research, we selected six sampling sites in the field: two sites were controls with no influences of turbid water from the dam and other remaining four sites were the stations for an assessment of potential turbid effects. We evaluated integrative health conditions throughout applications of various models such as necropsy-based fish health assessment model (FHA), Index of Biological Integrity (IBI) using fish assemblages, and Qualitative Habitat Evaluation Index (QHEI). Laboratory tests on fish exposure under 400 NTU were performed to find out impact of turbid water using scanning electron microscope (SEM). Results showed that fine solid particles were clogging in the gill in the treatments, while particles were not found in the control. This results indicate that when inorganic turbidity increases abruptedly, fish may have a mechanical abrasion or respiratory blocking. The stream health condition, based on the IBI values, ranged between 38 and 48 (average: 42), indicating a "excellent" or "good" condition after the criteria of US EPA (1993). In the mean time, physical habitat condition, based on the QHEI, ranged 97 to 187 (average 154), indicating a "suboptimal condition". These biological outcomes were compared with chemical dataset: IBI values were more correlated (r=0.526, p<0.05, n=18) with QHEI rather than chemical water quality, based on turbidity (r=0.260, p>0.05, n=18). Analysis of the FHA showed that the individual health indicated "excellent condition", while QHEI showed no habitat disturbances (especially bottom substrate and embeddeness), food-web, and spawning place. Consequently, we concluded that the ecological health in downstream of Yongdam Dam was not impacted by the turbid water.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.345-354
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• 2009

The review of statements and coastal development characteristics in South Korea were diagnosed by the consultation on the coastal area utilization in Korea. The occupation and the use of public water were dominated by installation of coastal structure and seawater supply and drainage whereas the reclamation areas were predominantly utilized for developing industrial complex, harbor, fishing port and road. The occupation and the use were dominant in western coast, but reclamation was dominant in southern coast of Korea. The number of utilization cases was particularly greater in Jeonnam, Gyeongnam, and Gyeonggi Province including Incheon. The number of the statements reviews increased by more than 200 cases in 2008 compared with 2007, and most of them were the simple statements. The statements related to ocean disposal of dredged sediment, reclamation, dredging sediment, seawater supply and drainage, and marine sand mining were submitted for review. Coastal utilization was especially active in the regions of seawater quality criteria I and II. In particular, special management sea areas designated under the relevant marine regulations were utilized mostly by reclamation for developing harbor, fishing port and coastal structure. Development activities in national parks comprised primarily structure installation and coastal maintenance. In the fisheries resources protection areas, 40% of the total cases accounted for coastal maintenance, 31% for structure installation, and 16% for seawater supply and drainage. In addition, alternative plans for the improvement in policies and system of marine environmental impact assessment were suggested to enhance the function and confidence of the consultation on the coastal area utilization in Korea.

• Journal of the Korean GEO-environmental Society
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• v.18 no.4
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• pp.23-29
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• 2017

As the Enforcement Ordinance of Environmental Policy Act was revised in 2013, Total Organic Carbon (TOC) was added as an indicative parameter for organic matter in Water and Aquatic Ecosystem Environmental Criteria. Under these imminent circumstances, a regulatory standard is needed to achieve the proposed TOC limitation control water quality from the STP (Sewage Treatment Plant). In this study, a electrolysis utilizing the electrochemical reaction was investigated in lab-scale experiments for the treatment of TOC in sewage effluent. TOC reduction by a electrolysis was investigated response surface methodology using the Box-Begnken methods were applied to the experimental results. A central composite design was used to investigate the effects of the independent variables of electrode space ($x_1$), current density ($x_2$) and electrolyte concentration ($x_3$) on the dependent variables removal efficiency of TOC (y). The optimal conditions for electrolysis were determined: electrode space, current density and electrolyte concentration were 50 mm, $10.3mA/cm^2$ and 0.1M, respectively. Statistical results showed the order of significance of the independent variables to be electrode space > current density > electrolyte concentration.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.9
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• pp.533-541
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• 2015

We investigate the Japan's Master Plan of Comprehensive Sewerage System (JMPS) and Lake Biwa basin sewerage and suggest future development direction of the Watershed Sewerage System Maintenance Plan in Korea enforced on February 2, 2013. The JMPS is designed for compliance with the environmental standard for water quality under the Environmental Policy Act. The effluent standards applied in the master plan of Lake Biwa's Sewerage Plan for the Lake Biwa is tougher than the national standards. Therefore the Lake Biwa Baisn Sewerage System was the first in Japan to adopt facilities that perform advanced treatment for nitrogen and phosphorus removal. BOD, SS, T-N and T-P concentrations of discharge water of sewage are 0.9, 0.6, 5.5, 0.06 mg/L, respectively. Especially removal efficiency for BOD is 99.5 percent. It is necessary to study the diversification of the evaluation criteria, cost minimization approach, subsidy system improvement, economic concept of discharge load adjustment system and establishment of basin sewerage concept for the development of the basin sewerage plan in Korea.