• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.7
• /
• pp.3285-3294
• /
• 2012

A field test on mud flat remediation was carried out in order to observe the effects of the treatments such as microbial dose and an oxygen releasing compound like $CaO_2$. The size of each treatment site was $100m^2$ and the dosage was 3.6 kg per site. The 6 week monitoring showed that pH on two sites was below 7 and ORP increased from .178~-188 mV to .121~-142 mV. In Ignition loss and COD there were no significant changes. Meanwhile nitrogen and phosphorus concentrations changed: ammonia concentration decreased both on control and treatment sites. Nitrate nitrogen decreased more on combined treatment site than on single microbial treatment (11.3% vs. 7.3%) probably because the extra oxygen supplied by $CaO_2$ formed more oxic environment so that the facilitated nitrification might produce more nitrate but the nitrate would be much rapidly released into the water layer out of the sediment. That also explains the total nitrogen reduction(6.1%). Similarly, T-P and $PO_4-P$ reduced by 29% and 31.8%, respectively on combined treatment sites, resulting from the phosphorus release effect though the initial concentrations of the two factors were considerably high.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.10
• /
• pp.1090-1098
• /
• 2005

Benzoyl peroxide is very toxic to aquatic organisms but environmental concentration or exposure effects were not studied. Distribution of the chemical among multimedia environment was estimated using EQC(Equilibrium Criterion) model based on the physical-chemical properties to evaluate the risk of benzoyl peroxide in environment. Level I describes a situation that 100,000 kg of benzoyl peroxide is emitted into the environment which is equilibrium and steady-state without degradation and advection condition. Level II describes a situation that a constant rate of 1,000kg/h of benzoyl peroxide is continuously discharged into the environment which is equilibrium and steady-state with degradation and advection condition. Level III describes a situation that 1,000 kg/h of benzoyl peroxide is continuously introduced in each air, water, soil, and sediment compartment which are non-equilibrium and steady-state with degradation, advection, and inter-media transfer condition. In Level I and II calculations the chemical was distributed to soil(68.3%) and water(28.7%). In Level III calculation it was primarily distributed to soil(99.9%) and overall residence time was estimated to be 3.4 years. Benzoyl peroxide can be persistent in environment.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.4
• /
• pp.258-264
• /
• 2014

This study is to investigate water quality changes of nitrogen (N) and phosphorous (P) at Gangjung-Goryeong Weir and Dalseong weir, in 2012-2013. Concentration of COD, TOC, T-N, T-P showed 3.5~6.8 mg/L, 3.4~6.5 mg/L, 1.8~4.0 mg/L, 0.08~0.12 mg/L respectively, in the Nakdong river main stream. Water quality of Dalseong weir showed lower level of contamination than that of Gangjung-Goryeong weir. Because of input loading of nutrients and organic matters from tributaries. At the analysis of sediments at each weirs, sedimentation fluxes of the hypolimnion represented 1.6~2.4 times higher than epilimnion fluxes. Sinking rate (%/d) of SS, N and P of the hypolimion showed in the range of 1.68 %/d~2.42 %/d. It is implied that the suspended matters seem to be floating in the water body. In the result of nutrients release experiment, release flux of nutrients in July showed 3~4 times higher than April. The reason was considered that nutrients is easily released in the anaerobic condition and at high water temperature.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.4
• /
• pp.1227-1240
• /
• 2014

Abandoned mines often cause environmental problems, such as alteration of landscape, metal contamination, and landslides due to a heavy rainfall. Geotechnical and rheological tests were performed on waste materials corrected from Imgi waste rock dump, located in Busan Metropolitan City. Debris flow mobility was examined with the help of 1-D BING model which was often simulated in both subaerial and subaqueous environments. To determine flow curve, we used a vane-penetrated rheometer. The shear stress (${\tau}$)-shear rate (${\dot{\gamma}}$) and viscosity(${\eta}$)-shear rate (${\dot{\gamma}}$) relationships were plotted using a shear stress control mode. Well-known rheological models, such as Bingham, bilinear, Herschel-Bulkley, Power-law, and Papanastasiou concepts, were compared to the rheological data. From the test results, we found that the tested waste materials exhibited a typical shear shinning behavior in ${\tau}$-${\dot{\gamma}}$ and and ${\eta}$-${\dot{\gamma}}$ plots, but the Bingham behavior is often observed when the water contents increased. The test results show that experimental data are in good agreement with rheological models in the post-failure stage during shearing. Based on the rheological properties (i.e., Bingham yield stress and viscosity as a function of the volumetric concentration of sediment) of waste materials, initial flowing shape (5 m, 10 m, and 15 m) and yield stress (100 Pa, 200 Pa, 300 Pa, and 500 Pa) were input to simulate the debris flow motion. As a result, the runout distance and front velocity of debris flow are in inverse propositional to yield stress. In particular, when the yield stress is less than 500 Pa, most of failed masses can flow into the stream, resulting in a water contamination.

• Journal of Life Science
• /
• v.28 no.4
• /
• pp.483-487
• /
• 2018

Cypermethrin, a commonly used domestic and agricultural pyrethroid pesticide, is widely considered detrimental to the environment and to many organisms because of its residual property and toxicity. Cellulophaga lytica DAU203, isolated from coastal sediment, was chosen because it degrade cypermethrin. Cellulophaga lytica DAU203 effectively degraded cypermethrin, as the utilized carbon source and substrate, in a mineral salt medium. Effective factors, such as carbon source, nitrogen source, initial pH, and temperature, for cypermethtin biological degradation by Cellulophaga lytica DAU203 were analyzed by one factor at a time method. Temperature ($22{\sim}42^{\circ}C$), initial pH (5~9), and yeast extract concentration (0.1~2.5%[w/v]) were selected as the three most important factors. There were optimized at $33.4^{\circ}C$, pH 7.7, and 2.4%(w/v) by response surface methodology, respectively. The Box- Behnken design consisting of 46 experimental runs with three replicates was used to optimize the independent variables which significantly influenced the cypermethrin biological degradation. This model for cypermethrin degradation by Cellulophaga lytica DAU203 is highly significant (p<0.05). Under the optimized condition, Cellulophaga lytica DAU203 degraded approximately 83.7 % of the cypermethrin within 5 days. These results suggest that Cellulophaga lytica DAU203 may be useful for the biological degradation of cypermethrin in cypermethrin-contaminated environments.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.6
• /
• pp.726-734
• /
• 2018

The total number of Sea Area Utilization Consultation in the environment management sea areas reviewed from 2015 to 2017 were 60. The number of development projects in the environment conservation sea areas decreased steadily, but special management sea areas increased. Development types in environment management sea areas showed that artificial structure installation was the highest ratio, followed by fishery port development and construction of habor and coastal maintenance and sea water intake and draining. By comparing the trend of water quality changes using marine environment information system (MEIS) data in the environment management areas from 2006 to 2017, COD showed no significant changes but the environment conservation sea areas increased slightly, and the concentration of TN and TP decreased. Gwangyang and Masan bays in the special management sea areas and Gamak bay in the environment conservation sea areas displayed oxygen deficient mass in the summer. As the use of development projects of the environment management sea areas are performed continuously, an analysis of the status of sufficient water quality changes is necessary for environmental impact assessment (Sea Area Utilization Consultation) in the marine environment and should be evaluated mainly for management of contamination by diagnosing thoroughly water quality effects and the pollution of sediment. Especially, the water quality goal for the purpose of designation in each of the environment management sea areas is set clearly, connection with pollution source control and the total pollution load management system (TPLMS) should be proposed and measured to reduce the amount of contaminated water.

• Economic and Environmental Geology
• /
• v.39 no.1 s.176
• /
• pp.39-51
• /
• 2006

Rare earth elements(REEs) in transgressive shelf core sediments were analysed to identify constraints of REE distribution patterns and sediment provenances in the northern East China Sea(ECS). Sediments of Chinese and Korean rivers, such as Huanghe and Yangtz rivers, Keum and Yeongsan rivers that supply sediments to the northern ECS, were also analysed to figure out their typical REE distribution patterns. The distribution patterns of Chinese and Korean river sediments, which are normalized with upper continental crust (UCC) REE values, appear to be enriched in middle rare earth elements (MREEs) in Chinese river sediments, whereas in light rare earth elements (LREEs) in Korean river sediments. We assign the MREE-enriched convex-type distribution pattern in Chinese river sediments as 'C-type', and the LREE-enriched linearly decreasing pattern in Korean river sediments as 'D-type'. A major constraint of the REE concentration in northern ECS core sediments is interpreted to be LREE-enriched monazite $((Ce,\;La)PO_4)$ that is ubiquitous in and around the study area. Meanwhile, the distribution pattern of northern ECS sediments appears to be between the C-type and the D-type. We suggest that the nothern ECS sediments are the mixture of China and Korea riverine sediments that have been accumulated in paleo-river mouth, paleo-coast, and present-day shelf environment as well.

• Korean Journal of Ecology and Environment
• /
• v.33 no.4 s.92
• /
• pp.358-365
• /
• 2000

To evaluate the influences of stocking and removal of silver carp on plankton communities and physicochemical parameters, fish biomanipulation was conducted in six enclosures constructed on the coast of a hypertrophic lake during the summer of 1997. Of these, three enclosures were established for the fish-stocking experiment; one fishless enclosure used as a control and two enclosures with high and low densities of fish. The other three enclosures for the fish-removal experiment were prepared in an entirely converse process compared to that for fish stocking. The results of randomized intervention analysis (${\alpha}=0.05$) showed significant changes in several physicochemical parameters and plankton communities after fish stocking and removal. Fish stocking decreased water transparency, DO, pH and chi-a (> $40\;{\mu}m$), while increasing the concentration of nitrogen and chi-a (<$2\;{\mu}m$). However, water transparency did not increase by fish removal. Small plankton communities, such as picocyanobacteria, eukaryotic picoplankton and ciliates (<$2\;{\mu}m$) showed significant reciprocal changes after both fish treatments: increase by the presence of fish and decrease by the absence of fish. No count of large sized phytoplankton and zooplankton showed significant change in the presence of fish, while large zooplankton, Diaphanosoma, Cyclopida and nauplii were significantly increased by fish removal. Although the frequent heavy-winds and endless supply of phosphorus from the lake sediment strongly disturbed the fish behavior and enclosure management, the stocking and removal of silver carp showed an obvious reciprocal influences on plankton communities and its physico-chemical parameters in a shallow-hypertrophic lake.

• Journal of the Korean GEO-environmental Society
• /
• v.21 no.3
• /
• pp.13-21
• /
• 2020

The purpose of this study is to evaluate the concentrations of heavy metals in the marine sediments near the Masan bay and the Nakdong estuary, and to investigate the pollution intensity levels of six heavy metals using the existing pollution intensity assessment method. According to the US environmental protection agency, in the case of Cu, the B1 area was classified as severe pollution, while in Ni and Zn, it was classified as moderate pollution in some areas. According to the classification of Igeo, EF and PERF, the A and B regions were polluted by Cd. In particular, in the B1 region, Igeo, EF, and PERF values were the highest in all regions, and were regarded as serious pollution. According to the mean PEL quotient classification, which takes into account the effects of all six heavy metals, there is a 21% probability of toxicity from heavy metals in all regions. The highest concentration of Cd in the B1 region is 1.5 mg/kg. Therefore, the contamination of Cd contained in sediment near Masan Bay is serious, so it is necessary to clarify the cause and take careful approach to future treatment.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.2
• /
• pp.17-29
• /
• 1983

The siltation of the Gun-San New Harbour is a serious problem to keep the available water depth of the basin. So, in order to make clear the behaviour of the suspended load flowing in and out of the Gun-San New Harbour obviously, the samples of the suspended load at the appropriate points were collected in the estuarine area near the Harbour and at the same time the tidal current velocities measured. Their suspended load concentrations and salinities were analyzed, and emphasis has been placed on the characteristics of the suspended load concentrations and on the relationship between the concentration and the tidal flow as well as the wave. As a result, the authors obtained the followings; 1) The main source of the suspended load in the Geum River estuarine area is transported from its upstream during floods and deposited rapidly due to the salt water, and the settled sediment is resuspended due to the tidal flow and the wave action, transported and settled again. Such a process is periodically repeated according to the tidal curve. 2) The concentrations are, in general, becoming larger with the increase of the tidal range and the wave height, and vice versa. Especially, the concentrations are relatively large in the winter season of which the wave height is larger than another seasons.