• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.2
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• pp.68-74
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• 2009

Polycyclic aromatic hydrocarbons (PAHs), one of ubiquitous organic pollutants in marine environments, are major toxic components of petroleum and are produced during the incomplete combustion of organic materials. As shipyards are located inside of natural or artificial semi-enclosed bay, even a relatively weak environmental disturbance by ship-building activity can cause severe damage to marine ecosystem in the bay. Many studies of pollution in shipyard area have been focused on the antifouling agent, like tributyltin. This study aimed to investigate the effect of ship-building activity on PAH contamination. Total PAHs concentration was higher nearby and inside shipyard area than outside, implying that shipyard could be one of major source area of PAH contamination to pose harmful effects to surrounding environments. Through PAH profile and source recognition index, the source of PAHs inputs in this area was estimated to originate from both petrogenic and pyrogenic origin. PAH levels showed a significant correlation with total butyltins, indicating that ship-building activity influenced PAH concentration and distribution. Vertical distribution of PAHs historically confirmed the correlation between shipbuilding activity and PAHs contamination.

• Journal of Life Science
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• v.23 no.3
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• pp.341-346
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• 2013

The disappearance of seaweed flora in some rocky areas, which is known as algal whitening, barren ground, coralline flats, or deforested areas, is associated with some species of coralline algae. To determine the biological characteristics of a representative species of crustose coralline alga, the 18S rDNA gene was sequenced to identify the genus Lithophyllum. According to its morphological and distributional characteristics, it was deduced to be L. yessoense. Viability was measured using triphenyl tetrazolium chloride and showed high viability from December to February. Culture conditions of $16^{\circ}C$, a 16 hr light, 8 hr dark cycle, and 30 ${\mu}E/m^2/s$ light intensity were optimal for maintaining the viability of the alga for up to five days. Included in the fatty acids was 9.7% ${\omega}$-3 eicosapentaenoic acid. An electron microscopy scan of the surface structure revealed round craters about 3.6 ${\mu}m$ in diameter, which were covered with rough, irregular, and angular polygon-shaped structures about 1.0 to 3.7 ${\mu}m$ in size. Based on the composition and structure found in our study, biomimetic coralline alga might become an environmentally friendly antifouling material against the attachment of soft foulants.

• Membrane Journal
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• v.31 no.2
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• pp.101-119
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• 2021

The demand for clean water is virtually present in all modern human societies even as our society has developed increasingly more advanced and sophisticated technologies to improve human life. However, as global climate change begins to show more dramatic effects in many regions in the world, the demand for a cheap, effective way to treat wastewater or to remove harmful bacteria, microbes, viruses, and other solvents detrimental to human health has continued to remain present and remains as important as ever. Well-established synthetic membranes composed of polyaniline (PANI), polyvinylidene fluoride (PVDF), and others have been extensively studied to gather information regarding the characteristics and performance of the membrane, but recent studies have shown that making these synthetic membranes conductive to electrical current by doping the membrane with another material or incorporating conductive materials onto the surface of the membrane, such as allotropes of carbon, have shown to increase the performance of these membranes by allowing the adjustability of pore size, improving antifouling and making the antibacterial property better. In this review, modern electrically conductive membranes are compared to conventional membranes and their performance improvements under electric fields are discussed, as well as their potential in water filtration and wastewater treatment applications.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.120-129
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• 2023

Marine structures are subject to damage not only from sea salt but also from the adhesion of marine microorganisms and suspended particles, which cause additional damages. In order to prevent this, periodic coating is employed in the case of vessels to maintain the necessary performance. However, it is true that periodic coating is difficult for concrete or steel support structures, and there is a risk of marine environmental pollution. In this study, authors developed an anti-fouling coating agent using eco-friendly materials that possess hydrophilic cellulose nanofibers and AKD(alkyl ketene dimer). To achieve a homogeneous mixture, the content of cellulose nanofibers was fixed at 1 %, and AKD, distilled water, and waste glass were mixed using a digital mixer and homogenizer. The contact angle of the prepared coated surface was observed to be over 130°, indicating sufficient performance even in a water droplet flow test with a 15° slope, suggesting self-cleaning capability. Furthermore, through the analysis of viscosity characteristics at different temperatures, it was confirmed that the application is feasible at room temperature. Microstructure analysis also verified that the coating agent is uniformly applied to the concrete surface.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.256-265
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• 2023

Chlorothalonil is continuously introduced into the marine environment and has significant toxic effects on various marine organisms, however, research on its effect on seaweed is limited. Therefore, we analyzed the impact of chlorothalonil on the early life stages of major aquaculture species in Korea, Undaria pinnatifida. U. pinnatifida female gametophytes were exposed to different concentrations of chlorothalonil (0, 0.03, 0.05, 0.10, 0.20, and 0.40 mg L^-1), and their survival rate and relative growth rate were analyzed. The no observed effect concentration (NOEC), lowest observed effect concentration (LOEC), and median lethal concentration (LC50) for female gametophyte survival were determined as 0.05, 0.10, and 0.141(0.121-0.166)mg L^-1. NOEC, LOEC, and median effective concentration (EC50) for relative growth rate were 0.10, 0.20, and 0.124 (0.119-0.131) mg L^-1. Therefore, female gametophytes of U. pinnatifida are expected to experience toxic effects at concentrations above 0.05-0.10 mg L^-1 of chlorothalonil. These research findings are anticipated to serve as crucial reference data for evaluating the effects of chlorothalonil on the health of U. pinnatifida in the early life stages.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.427-438
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• 2023

Biocide dichlofluanid breaks down quickly and accumulates easily in sediment, potentially causing a persistent impact on various marine organisms. We analyzed the potential toxicity of dichlofluanid on major aquaculture species in Korea, Undaria pinnatifida. Female gametophytes of U. pinnatifida were exposed to dichlofluanid at concentrations of 0, 1, 2, 4, 8, 16, and 32 mg L^-1, and their survival and relative growth rate were analyzed. The no observed effect concentration(NOEC), lowest observed effect concentration (LOEC), and median lethal concentration (LC₅₀) for female gametophyte survival were determined as 1, 2, and 10.82 (95% CI: 8.87-13.23) mg L^-1, respectively. The NOEC, LOEC, and median effective concentration (EC₅₀) for relative growth rate were 1, 2, and 6.58 (95% CI: 6.03-7.17) mg L^-1, respectively. Female gametophytes of U. pinnatifida were expected to experience toxic effects at concentrations above 2 mg L^-1 of dichlofluanid. These research findings are expected to serve as important reference data for evaluating the toxicity effects of U. pinnatifida in its early life stages when exposed to dichlofluanid.

• Environmental Analysis Health and Toxicology
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• v.18 no.2
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• pp.89-94
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• 2003

Tributyltin (TBT) used world-wide in antifouling paints for ships is a widespread environmental pollutant and cause reproductive organs atrophy in rodents. At low doses, antiproliferative modes of action have been shown to be involved, whereas at higher doses apoptosis seems to be the mechanism of toxicity in reproductive organs by TBT. In this study, we investigated that the mechanisms underlying DNA fragmentation induced by TBT in the rat leyding cell line, R2C. Effects of TBT on intracellular Ca$\^$2+/ level and reactive oxygen species (ROS) were investigated in R2C cells by fluorescence detector. TBT significantly induced intracellular Ca$\^$2+/ level in a time-dependent manner. The rise in intracellular Ca$\^$2+/ level was followed by a time-dependent generation of reactive oxygen species (ROS) at the cytosol level. Simultaneously, TBT induced the release of cytochrome c from the mitochondrial membrane into the cytosol. Furthermore, ROS production and the release of cytochrome c were reduced by BAPTA, an intracellular Ca$\^$2+/ chelator, indicating the important role of Ca$\^$2+/ in R2C during these early intracellular events. In addition, Z-DEVD FMK, a caspase-3 inhibitor, decreased apoptosis by TBT. Taken together, the present results indicated that the apoptotic pathway by TBT might start with an increase in intracellular Ca$\^$2+/ level, continues with release of ROS and cytochrome c from mitochondria, activation of caspases,and finally results in DNA fragmentation.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.518-527
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• 2020

The aim of this study was to define the toxic effects of diuron and irgarol, which are new-antifouling agents, on the fertilization rate and normal embryogenesis rate in the sea urchin, Hemicentrotus pulcherrimus. In addition, the study was intended to confirm the hindrance of development in sea urchins. The fertilization rate of H. pulcherrimus was not decreased by the tested concentrations. However, the normal embryogenesis rate was decreased in a concentration-dependent manner. The 50% effective concentrations (EC₅₀) of normal embryogenesis rate were 7.12 mg L^-1 and 2.31 mg L^-1, respectively. As the embryos developed into pluteus larvae, after 18 h of exposure to diuron and irgarol at EC₅₀, development of the early gastrula stage was delayed, and significant developmental delays were observed after 24 h. After this, continuous developmental delays were observed in the process leading to the early gastrular, gastrular, early pluteus, and pluteus stages. Therefore, the toxic effects of diuron and irgarol on sea urchins were attributed to the delay in the developmental processes in the early life stages. Diuron and irgarol are highly persistent in the environment and have known-well toxic effects on various marine organisms including invertebrates, as shown in this study. Therefore, it is urgent to establish an environmental protection strategy to prevent the pollution of and preserve the marine environment.