• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.61-65
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• 2012

Once oil has spilled, oil spill responders use a variety of countermeasures to reduce the adverse effects of spilled oil on the environment. Mechanical methods of containment and recovery are preferred as the first response when the use of other methods fail or are ineffective. In these cases, the application of oil dispersants shall be use only as a last resort. While effectiveness of dispersants in removing oil form the sea surface is proven, the use of dispersants is controlled in almost all countries due to the toxicity of their active agents and the dispersed oil on the marine environment. However, according to reports, after dispersant application, no significant toxicity to fish or shrimp was observed in the field-collected samples. Moreover, the results also indicate that dispersant-oil mixtures are generally no more toxic to the aquatic test species than oil alone. During the Deepwater Horizon Incident, dispersants were applied to floating oil and injected into the oil plume at depth. These decisions were carefully considered by state and federal agencies, as well as BP, to prevent as much oil as possible from reaching sensitive shoreline habitats. Net Environmental Benefit Analysis for dispersant use assumed that dispersants appear to prevent long-term contamination resulting absence of oil in the substrate and will benefit marine wildlife by decreasing the risk of significant contamination to feathers or fur. Further study to use dispersants with scientific baseline is needed for our maritime environment which consistently threaten huge oil spill incidents occurrence.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.478-485
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• 2013

Fish field survey, especially fish distribution and their ecological characteristics, was performed in the downstream region of Gyeongan stream during the period of before (June) and after (October) the summer monsoon in 2010. Depending on the characteristics of each site, fyke net or casting net was used for fish sampling. Feeding classification was determined by the analysis of stomach contents. Total number of family and species sampled were 5 and 17, respectively. The dominant family was Cyprinidae (12 species), and relative abundance (RA) of the most dominant species, Lepomis macrochirus and Zacco platypus, was 38% and 24%, respectively. Exotic species and Korean endemic species observed were 3 (423 individuals, RA 44%) and 4 (98 individuals, RA 10%), respectively. Tolerance guild analysis as characteristics of ecological indicators revealed an undoubtedly high percentage (97%), compared to others as reflected by the identification of just one sensitive species. Analysis of trophic guilds showed that L. macrochirus dominated among insectivores (44% RA). The food of L. macrochirus composed of, aquatic insects, benthic invertebrates, zooplankton, Chironomidae, and waterweed. Thus, we determined that L. macrochirus could be classified as insectivores (partially carnivores) in this study. Conversely, Z. platypus consumed Cladocera exclusively, greater than 90% of their feed. We presume that stable isotope analysis would identify the exact position of these species in the food web.

• The Korean Journal of Malacology
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• v.26 no.1
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• pp.91-95
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• 2010

Density-dependant growth and mortality rate of Manila clam Ruditapes philippinarum reared in net cages was investigated in Gomso Bay, Korea where unusually high mortality of clams has been reported. For the experiment, four groups of clam cages were set up with a density of $2,000clams/m^2$ (group A), $1,000clams/m^2$ (group B), $500clams/m^2$ (group C) and $100clams/m^2$ (group D). Mortality and growth of clams in each experimental cage was monitored biweekly from May 2001 to September 2001. Highest mortality in group A was observed in late August, while highest mortality of rest groups was observed in early September. In September, the cumulative mortality in group A was 99%, while it was 93.2% in group B, 91.2% in group C and 88% in group D. Shell growth rate of clams in thecages was found to be density dependent; monthly shell length increase was 0.67 mm in group A, 1.33 mm in group B, 1.63 mm in group C and 1.71 mm in group D. Our study indicated that clam growth and mortality in the Bay is density dependent and the growth and survival rate is negatively correlated with the density.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1189-1192
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• 2005

Due to their slow degradation properties, hydrophobic organic contaminants in estuarine sediment have been a concern for risks to human health and aquatic organisms. Studies of fate and transport of these contaminants in estuaries are further complicated by the fact that hydrodynamics and sediment transport processes in these regions are complex, involving processes with various temporal and spatial scales. In order to simulate and quantify long-term attenuation of Polycyclic Aromatic Hydrocarbons (PAH) in the Elizabeth River, VA, we develop a modeling approach, which employs the U.S. Environmental Protection Agency's water quality model, WASP, and encompasses key physical and chemical processes that govern long-term fate and transport of PAHs in the river. In this box-model configuration, freshwater inflows mix with ocean saline water and tidally averaged dispersion coefficients are obtained by calibration using measured salinity data. Sediment core field data is used to estimate the net deposition/erosion rate, treating only either the gross resuspension or deposition rate as the calibration parameter. Once calibrated, the model simulates fate and transport PAHs following the loading input to the river in 1967, nearly 4 decades ago. Sediment PAH concentrations are simulated over 1967-2022 and model results for Year 2002 are compared with field data measured at various locations of the river during that year. Sediment concentrations for Year 2012 and 2022 are also projected for various remedial actions. Since all the model parameters are based on empirical field data, model predictions should reflect responses based on the assumptions that have been governing the fate and sediment transport for the past decades.

• Nuclear Engineering and Technology
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• v.45 no.1
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• pp.1-12
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• 2013

This paper describes the radiation doses to human and non-human biota in the Republic of Korea, as a result of the Fukushima nuclear accident. By using the measured airborne activity and ground deposition, the effective and thyroid doses of five human age groups (infant, 5 years, 10 years, 15 years and adult) were estimated by the ECOSYS code, and the whole body absorbed dose rate of the eight Korean reference animals and plants (RAPs) was estimated by the K-BIOTA (the Korean computer code to assess the risk of radioactivity to wildlife). The first-year effective and thyroid human doses ranged from 5.7E-5 mSv in the infant group to 2.0E-4 mSv in the 5 years group, and from 5.0E-4 mSv in the infant group to 3.4E-3 mSv in the 5 years group, respectively. The life-time (70 years) effective and thyroid human doses ranged from 1.5E-4 mSv in the infant group to 3.0E-4 mSv in the 5 years group, and from 6.0E-4 mSv in the infant group to 3.5E-3 mSv in the 5 years group, respectively. The estimated maximum whole body absorbed dose rate to the Korean RAPs was 6.7E-7 mGy/d for a snake living in soil (terrestrial biota), and 2.0E-5 mGy/d for freshwater fish (aquatic biota), both of which were far less than the generic dose criteria to protect biota from ionizing radiation. Also, the screening level assessment for ERICA's (Environmental Risks from Ionizing Contaminants: Assessments and management) limiting organisms showed that the risk quotient (RQ) for the estimated maximum soil and water activity was significantly less than unity for both the terrestrial and freshwater organisms. Conclusively, the radiological risk of the radioactivity released into the environment by the Fukushima nuclear accident to the public and the non-human biota in the republic of Korea is considered negligible.

• The Journal of Fisheries Business Administration
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• v.34 no.1
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• pp.137-156
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• 2003

Increasingly, leisure time is being used for outdoor recreational activities, and fishing is one of the principal forms of marine recreation. Marine recreational fishing is a popular activity in Korea and this activity has led to the development of a sector of substantial social and economic value. Also it is considered as one of the important outdoor leisure industries in Korea. With rising of income level and development of marine outdoor leisure industries, social, economic demand increase of marine recreational fishing are showing us new advance ability of marine aquatic bio-industry. However the recreational use of fish stocks has become an important consideration in the public and environmental economic analysis of management aspect of fishing, having grown considerably over recent years to reach a level in Korea where the fish stocks and coastal ecosystem has become a significant management problem. we are inevitably facing marine environmental deterioration and overfishing in marine recreational fishing. In this study, not only resources and environmental problems which are occurred by recreational fishers, but also illegal fishing behaviors and other problems such as market's failure are going to analyze basic management theories and methods of recreational fishing through mathematical principals and economic rents which maximize net social benefits. In view of the likelihood of marine recreational fishers adopting high rates of discount, the conservation of fish resources would appear to require continual public surveillance and control of the physical yield and condition of the fish stocks and the optimal use level. The institutional management of recreational fisheries is the way of escaping the collapse of recreational fisheries just like as the situation of management's failure of commercial fisheries worldwide. One of the effective management measure is a license system. In this system, optimal fee is paid by recreational fishers, which prevent them from overfishing, environmental problems to some extents and carry out the optimal number of outings. And money obtained by license fee should be spent for more improvement fishing culture and welfare for marine recreational fishing. Marine recreational fishing is to be promoted under sound conservation and management principles.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.1184-1193
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• 2015

Monitoring for megalocytivirus infection was conducted for ten months from March to December in 2013 in 15 aquatic farms culturing, red sea bream, rock bream, rock fish and black sea bream around Tongyoung coastal area in Korea, to assess spatial and temporal variability of detection prevalence, and to explore possible links with seawater temperature. In nested-PCR targeted major capsid protein (MCP) gene, asymptomatic megalocytivirus infection was detected in the externally healthy farmed fish with a significant prevalence in range from 0 to 58.3% for ten months. Higher prevalence of megalocytivirus (46.7% - 57.1%) was observed in high water temperature season from September to November than that in other months with lower prevalence of 0.0% to 20.0%. Even though an acute infection of megalocytivirus was occurred in rock bream (positive in the first PCR) with high mortality in one of fifteen farms, there was no expansion or transmission of the disease to the rock fish and red sea bream culturing in net cage just proximal to the rock bream cage in which disease outbreaked. Nucleotide sequence analysis of the cloned MCP gene isolated asymptomatically infected rock fish revealed that the megalocytivirus in this study was clustered together with the rock bream iridovirus (RBIV) under the subgroup II of the genus megalocytivirus (Iridoviridae), which is known to be the major megalocytivirus strain in Korea. The typical histopathological signs were not found in the spleen of rock fish asymptomatically infected by megalocytivirus. Experimental infection of rock bream with the spleen homogenate of the rock fish infected asymptomatically did not induce any mortality unlike the homogenate of infected rock bream with hih mortlity. However, these results may suggest that the asymptomatic infection of megalocytivirus in other fish species can be a potential risk threatening aquaculture industries as a transmission factor of megalocytivirus to susceptible fish species, especially rock bream.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.231-244
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• 2019

Zooplankton is essential biological assemblage in understanding the structure and function of aquatic ecosystems, since it plays as a linkage between primary producers and higher trophic level organisms such as fish. Although zooplankton has planktonic characteristics, the sampling and treatment methods for its community analyses are more complicated and variable compared with phytoplankton due to its high diversity in body size and species-specific depth selection behaviors. In the present paper, we reviewed representative classical methods for field sampling and treatments of freshwater zooplankton in relation with quantification of its community structure, and suggested appropriate methods depending on various research objectives.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4265-4271
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• 2022

Determination of ¹³⁷Cs, ⁴⁰K and ²¹⁰Po in water, bottom sediments and suspended matter of river systems of the Can Gio Biosphere Reserve, Vietnam was carried out. The average activity concentration of ¹³⁷Cs in waters of Ca Gau and Long Tau was 0.89 ± 0.14 and 1.08 ± 0.15 Bq m^-3 and was comparable to the levels of this radioisotope in waters of the East Sea. The activity concentration of ¹³⁷Cs in bottom sediments was 2.23 ± 0.81 and 3.63 ± 1.24 Bq kg^-1. The activity concentration of ¹³⁷Cs in water and bottom sediments could be characterized as low. So, the water areas of the Ca Gau and Long Tau rivers could be attributed to areas with insignificant pollution by technogenic radionuclides. The ²¹⁰Po activity concentration in bottom sediments of the Ca Gau and Long Tau rivers ranged from 9.2 ± 1.2 to 25.5 ± 2.1 Bq kg^-1, which is typical for river bottom sediments. Such values indicate the absence of anthropogenic enhancement of the entry of this radionuclide into the Can Gio river systems. The ⁴⁰K activity concentration varied within 467 ± 42-651 ± 39 Bq kg^-1 and represented typical values of potassium content in the bottom sediments of coastal water bodies, subject to a significant influence of the lithogenic component of suspended matter.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.707-716
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• 2023

The influence of waste technological waters of thermal and fast reactors of Beloyarsk NPP (Russia) on the accumulation of ⁶⁰Co, ⁹⁰Sr and ¹³⁷Cs in macrophytes and ichthyofauna of the cooling pond has been studied. Critical radionuclides, routes of their entry into the ecosystem and periods of maximum discharge of radioisotopes into the cooling pond have been determined. It is shown that the technology of electricity generation at the Beloyarsk NPP, based on fast reactors, has a much smaller effect on the release of artificial radionuclides into the environment. Therefore, during the entire period of monitoring studies (1976-2019), the decrease in the specific activity of radionuclides of NPP origin in macrophytes was 13-25800 times, in ichthyofauna 1.5-44.5 times. The maximum discharge of artificial radionuclides into the Beloyarsk reservoir was noted during the period of restoration and decontamination work aimed at eliminating the emergencies at the AMB reactors of NPP. The factors influencing the accumulation of artificial radionuclides in the components of the freshwater ecosystem of the Beloyarsk cooling pond have been determined, including: the physicochemical nature of radioisotopes, their concentration in surface water, the temperature of the aquatic environment, the trophicity of the reservoir, the species of hydrobionts.