• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.108-113
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• 1983

There has been two kind of research fields in evaluating the ecotoxicity of chemicals The one is a bioassay and the other is an ecosystem analysis. The toxicants are transported into different biota, which have quite different environmental behaviour patterns and toxic properties. The effects of pesticides (butachlor, carbofuran, and tricyclazole) on periphyton community was studied by analyzing content of chlorophyll-a and autotrophic index (AI) that is a means of determining the trophic nature of the periphyton community. Results indicated that the content of chlorophyll-a was not influenced by the pesticides. The growth of algae was inhibited by sunshine period. And AI value is 43-2027: the large value indicates heterotrophic periphyton community, and was not affected by pesticides.

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.300-306
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• 2000

The rate of apparent nitric oxide (NO) release, as measured in the exhaust gas of green alga, Scenedesmus obliquus, depended on the light intensity and pH. It doubled after lowering the temperature from $25^{\circ}C{\;}to{\;}15^{\circ}C$ and strongly decreased from $35^{\circ}C{\;}to{\;}42^{\circ}C$. The Scenedesmus cells, deficient in nitrogen or phosphorus, demonstrated a significant increase in NO production following their transfer to nitrate- and phosphate-rich media. The addition of herbicides (DCMU and glyphosate) or toxic concentrations of $Cu^{2+}{\;}or{\;}Fe^{3+}$ produced strong NO peaks, resembling those that occurred after sudden darkening. An increase in the $Ni^{2+}$ concentration to 20 ppm resulted in a gradual increase of NO release from the initial ~1.5 ppbv to>20 ppbv, whereas $Cd^{2+}$ instantaneously suppressed the NO by the cultures of Scenedesmus was not altered by L-NNA, an inhibitor of nitric oxide synthase (NOS), or by its substrate, L-arginine. This seems to exclude the role of NOS in the NO formation under study. Accordingly, it can be assumed that the rate of NO formation is mainly a function of dynamic nitrite pool sizes and environmental factors significantly affect the NO production in algae.

• Environmental Engineering Research
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• v.12 no.1
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• pp.21-29
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• 2007

For this study, we polymerized polyacrylamide base flocculants (PAA) and tested their properties and settling efficiency as a treatment for potable water. The most common chemicals for potable water treatment in Korea are alum or PAC. However, due to various reasons (such as rainy season or algae), inorganic flocculants cannot be solely depended on to solve all the problems caused by the poor quality of inflow water. When PAA coupled with coagulants in a potable water purification process is used, the turbidity removal efficiency increases by a factor of three on a single chemical system using PAC (Raw water: 5.21 NTU; Treated PAA+PAC: 0.34 NTU; and, Treated PAC: 1.04 NTU). It is possible to offset the toxic effect of residual monomers in treated water using PAA, because the concentrations of residual acrylamide are less than 400 mg/L in the polymer itself and less than $0.04\;{\mu}g/L$ in the treated water base at a dosage of 0.1 mg/L. Therefore, PAAs may be a workable, and dependable, potable water treatment process for the high pollutant level of resource water.

• Environmental Analysis Health and Toxicology
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• v.17 no.2
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• pp.135-140
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• 2002

Sodium hypochlorite (NaOCl) has been demonstrated to be effective against algae that cause red tides. To secure the environmental safety of this chemical for practical use, toxic effects of NaOCl were evaluated in two important aquaculture fishes, flounder and rockfish. At concentrations above 2.5 and 5 ppm for 1 hr, mortality occurred in flounder and rockfish, respectively. Flounder, however, did not die at 2 ppm up to an 8 hr exposure, nor did lipid peroxide level change at the same concentration in 1 hr. Plasma glucose level significantly increased in 1 hr with more than 2 ppm exposure. The results indicate that NaOCl may not induce persistent severe toxicity in flounder and rockfish at the algicidal concentration, 0.5 ppm.

• Environmental Engineering Research
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• v.20 no.1
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• pp.1-18
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• 2015

The biosorption process has been established as characteristics of dead biomasses of both cellulosic and microbial origin to bind metal ion pollutants from aqueous suspension. The high effectiveness of this process even at low metal concentration, similarity to ion exchange treatment process, but cheaper and greener alternative to conventional techniques have resulted in a mature biosorption technology. Yet its adoption to large scale industrial wastewaters treatment has still been a distant reality. The purpose of this review is to make in-depth analyses of the various aspects of the biosorption technology, staring from the various biosorbents used till date and the various factors affecting the process. The design of better biosorbents for improving their physico-chemical features as well as enhancing their biosorption characteristics has been discussed. Better economic value of the biosorption technology is related to the repeated reuse of the biosorbent with minimum loss of efficiency. In this context desorption of the metal pollutants as well as regeneration of the biosorbent has been discussed in detail. Various inhibitions including the multi mechanistic role of the biosorption technology has been identified which have played a contributory role to its non-commercialization.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.162-162
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• 1998

Various natural compounds act as antioxidants in protection against lipid peroxidation. Lipid peroxidation yields a variety of decomposition products which have been implicated in not only decreasing the nutritional value of food, but also in developing an off-flavor and toxic substances. As a source of safer and more effective natural antioxidants of natural origin have been widely investigated. Some Indonesian plants have evaluated for their antioxidative activity, and suggested the possible existence of various antioxygenic compounds in them. We attempted to study such antioxygenic compounds with simple method evaluation. As we are interested in the natural product compounds, we examined of several sample such as edible sea-weeds, and some edible fruits. Sea-weed, Eisenia bicyclis, one of the edible brown algae, exhibited the activity. As a traditional food additive consumed by Indonesian, Garcinia parvifolia is used as taste supplement in region West Sumatra, have been studied. Our current studies on the semi-polar fractions shows the activity by the thiocyanate method test. Another sample, Garcinia mangostana, a famous fruit with sweet taste, the part kernel have also evaluated. The acidic fraction of the extract showed antioxidative activity. Some other active components were found in the neutral and BuOH fractions.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.597-605
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• 2009

Algae bloom occurred in reservoir in summer can cause taste and odor in water and disturb the flocculation and sedimentation processes in water treatment plant and cause sand filter plugging. It was also reported that microcystins, anatoxin and saxitoxin released from cyanobacteria had acute toxic effects on liver and nervous system. For these reasons, many advanced countries inclusive of WHO set the guideline for these toxins and cyanotoxins have been managed with regular monitoring in Korea as well. However, complex sample preparation steps such as a solid phase extraction (SPE) and derivatization are required with an existing analysis method with HPLC. We needed to improve an analysis method for low extraction efficiency and long sample preparation time. In this study, we have established a new LC/MS/MS method which can simultaneously determine 6 cyanotoxins (Microcystins-LR, Microcystins-RR, Microcystins-YR, Anatoxin-a, Saxitoxin, Neosaxitoxin) with only simple filtration step. When $75{\mu}L$ filterated sample was injected onto the LC-MS/MS, the recovery ranged from 86% to 112% and the MDL was $0.025{\sim}0.581{\mu}g/L$. We can make the MDL be lower than the guideline ($1{\sim}3{\mu}g/L$) of advanced countries with simple preparation.

• Environmental Engineering Research
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• v.24 no.1
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• pp.144-149
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• 2019

Landfill leachate constitutes one of the most polluting wastewaters. Their treatment was considered difficult due to the presence of high concentration of organic matter, ammonia, toxic organic compounds and heavy metals. Biological processes were found to be effective in several cases, but they are limited by the presence of inhibitory compounds in leachate. In this study we develop a biological process for the leachate biodetoxification using Trametes trogii (T. trogii; CLBE55). Results show that laccase activity, mycelia growth and chemical oxygen demand (COD) removal efficiencies varied depending on the leachate and ammonium concentration. Indeed T. trogii was able to grow in the presence of low concentration of landfill leachate of 10 and 30%. In fact, the biomass produced was 4.7 and 3.7 g/L, respectively leading to a COD removal of 66 and 53%, respectively. However, when the concentration of the introduced leachate exceeds 30%, the treatment efficiency and particularly the COD removal decreases to reach 15% at 100% leachate. The effect of the ammonia was also studied and results showed that the addition of 5 g/L of ammonia inhibited totally the production of laccase and the COD removal.

• Environmental Engineering Research
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• v.24 no.3
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• pp.397-403
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• 2019

Microcystis sp. is one of the most common harmful cyanobacteria that release toxic substances. Counting algal cells is often used for effective control of harmful algal blooms. However, Microcystis sp. is commonly observed as a colony, so counting individual cells is challenging, as it requires significant time and labor. It is urgent to develop an accurate, simple, and rapid method for counting algal cells for regulatory purposes, estimating the status of blooms, and practicing proper management of water resources. The flow cytometer and microscope (FlowCAM), which is a dynamic imaging particle analyzer, can provide a promising alternative for rapid and simple cell counting. However, there is no accurate method for counting individual cells within a Microcystis colony. Furthermore, cell counting based on two-dimensional images may yield inaccurate results and underestimate the number of algal cells in a colony. In this study, a three-dimensional cell counting approach using a novel model algorithm was developed for counting individual cells in a Microcystis colony using a FlowCAM. The developed model algorithm showed satisfactory performance for Microcystis sp. cell counting in water samples collected from two rivers, and can be used for algal management in fresh water systems.

• Journal of Marine Bioscience and Biotechnology
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• v.14 no.2
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• pp.76-85
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• 2022

In this study, a biodegradable packaging film was developed using two marine algae, Gelidium amansii, and Sargassum horneri. The chemical properties and microstructure of the developed film were evaluated using field emission scanning electron microscope, Fourier transform infrared spectroscopy, gas chromatography-Mass spectroscopy, and thermogravimetric analysis. Furthermore, the mechanical properties and toxicity of the film were evaluated using the ISO 1924 and IEC 62321 methods, respectively. The biodegradability of the film was evaluated according to ISO 14855-1:2012 method. The film was primarily made of cellulose and had biodegradability that was about 17 times greater than that of PBS, a representative eco-friendly plastic. Moreover, the mechanical properties improved by approximately 40% compared to the seaweed-based film of the previous study. The virulence test revealed that the content of all of the toxic substances listed in IEC62321 was below the measurement limit. An egg carton that can be used in practice was manufactured in accordance with ISO 534, and its applicability was tested using the biodegradable packaging film prepared.