• Environmental Analysis Health and Toxicology
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• 제16권2호
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• pp.67-74
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• 2001

In a previous study by Kim et al. (2000), sodium hypochlorite (NaOCl) has been demonstrated to be effective against algae that cause red tides. To secure the environmental safely of the chemical in practical use, effect of NaOCl, at concentrations required for algicidal activity, on the histology of rockfish and little neck clam was examined. When the animals were exposed to NaOCl at concentrations of 0.5 or 2ppm for 1 hr, there was no exposure-associated histological change in either animal. As the experimental exposure condition was set in consideration of the use, our results provide safety information necessary for practical application to marine fields.

• Environmental Analysis Health and Toxicology
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• 제17권2호
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• pp.135-140
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• 2002

넙치는 단기간 NaOCl에 대한 노출에 대해 2ppm이하에서는 육안적으로 관찰시 심각한 이상증상이 관찰되지 않았으며, 조피볼락에서는 2.5ppm까지 급성적으로 안전하였다. 넙치와 조피볼락에서의 1시간 LC$_{50}$은 각각 3.24ppm 및 7.58ppm이었다. 조피볼락을 NaOCl로 1시간 노출시키고 혈액학적 및 혈장생화학적 변수를 측정하였을 때 2ppm이상의 농도에서 glucose의 농도가 현저히 상승한 부분을 제외하고는 생화학적 변수에도 이상이 발견되지는 않았다. Glucose는 거의 모든 종류의 stress에 의해서 신속히 증가하는 변수로서 이 시험에서 발견된 증가현상도 NaOCl이 가진 냄새 또는 화학적 자극성에 의한 stress의 결과로 나타난 것으로 추정된다.

• ALGAE
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• 제29권4호
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• pp.311-319
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• 2014

The biocide sodium hypochlorite (NaOCl) is widely used for controlling algal growth, and this application can be extended to marine environments as well. This study evaluates the biocidal efficiency and cellular toxicity of NaOCl on the harmful dinoflagellate Cochlodinium polykrikoides, with emphasis on pigment production and antioxidant enzyme activity. The test organism showed dose-dependent decrease in growth rate on exposure to NaOCl, and the 72 h $EC_{50}$ was measured to be $0.584mg\;L^{-1}$. NaOCl significantly decreased pigment levels and chlorophyll autofluorescence intensity, indicating possible detrimental effects on the photosystem of C. polykrikoides. Moreover, it significantly increased the activities of antioxidant enzymes, suggesting the production of reactive oxygen species in the cells. These data indicate that NaOCl exerted deleterious effects on the photosynthetic machinery and induced oxidative damage in the dinoflagellate and this biocide could be effectively used for the control of algal blooms.

• 한국식품과학회지
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• 제29권6호
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• pp.1094-1100
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• 1997

본 연구는 옥수수 전분을 sodium hypochlorite(NaOCl)로 산화시킬 때 산화제의 농도, pH와 온도가 미치는 영향에 대하여 조사하였다. 전분의 산화 반응은 NaOCl 농도, pH와 온도의 영향을 받았다. 산화반응은 산화제가 3.0% active Cl/g starch 이하의 농도에서는 1차 반응, 3.75% active Cl/g starch이상의 농도에서는 2차 반응으로 나타났다. 1차 반응에서 산화제의 농도가 2.25% active Cl/g starch 까지는 반응속도 상수가 증가하였고, 그 이후의 농도에서는 일정한 값을 보였다. 산화에 따른 전분내 카르복실기 함량은 반응 초기에 급격히 증가하다가 반응이 진행되면서 증가정도가 완만해졌으며, NaOCl 농도가 증가함에 따라 카르복실기의 생성량도 증가하였다. 동일한 NaOCl 농도(1.5% active Cl/g starch)에서 전분의 산화는 pH 7에서 가장 빠르게 진행되었다 온도에 따른 전분의 산화속도를 1차식으로 해석한 결과, 온도가 증가됨에 따라 속도 상수(k)값이 증가되어 반응속도가 빨라지는 것을 알 수 있었다. 한편 Arrhenius 식으로부터 산화 반응의 활성화 에너지를 계산하였을 때 1차반응의 활성화 에너지는 약 13.45 kcal/mol이었다.

• 농업과학연구
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• 제20권1호
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• pp.18-24
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• 1993

일반소독제로 광범위하게 사용되는 NaOCl을 종자소독제로써 이용할 수 있는 방안을 확립하고자 종자전염에 의한 병해 발생이 많은 볍씨와 채소종자를 대상으로 소독 효과를 조사하였던 바 다음과 같은 결과를 얻었다. 1. NaOCl의 참깨 종자 소독 효과를 조사하였던 바 NaOCl의 농도가 높을 수록 그리고 침지시간이 길수록 종자 소독 효과가 뚜렷 하였으나 종자 발아 장해를 일으켰다. 종자발아율을 높이며 소독효과가 우수한 종자 처리 방법은 NaOCl 1-2%에서 10분간 침지하는 것이었고, 벼 종자소독 효과는 NaOCl 농도 1-2%에서 침지시간을 30분 이내로 하는 것이 좋았다. 2. 무, 배추 종자 소독 효과를 조사하였던 바 NaOCl 농도 1%에서 10분간 침지할 경우 각종 Alternaria균의 검출율을 현저히 저하시켰고, 고추종자에서는 NaOCl 농도 1%에서 10분간 침지할 경우 각종 탄저병균의 검출율을 현저히 저하시켰다. 3. 종자전염성 진균에 대한 NaOCl의 소독 효과는 종자소독제인 Benlate T에 비하여 참깨종자에서는 우수하게 나타났고, 볍씨에서는 비슷하였다. 그러나 NaOCl은 처리농도가 높고 시간이 긴 경우에는 발아장해를 초래하였다.

• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.44.1-44.9
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• 2020

Objectives: Phytic acid (IP6), a naturally occurring agent, has been previously reported as a potential alternative to ethylenediaminetetraacetic acid (EDTA). However, its effect on adhesion to sodium hypochlorite (NaOCl)-treated dentin and its interactions with NaOCl have not been previously reported. Thus, in this study, the effects of IP6 on resin adhesion to NaOCl-treated dentin and the failure mode were investigated and the interactions between the used agents were analyzed. Materials and Methods: Micro-tensile bond strength (µTBS) testing was performed until failure on dentin treated with either distilled water (control), 5% NaOCl, or 5% NaOCl followed with chelators: 17% EDTA for 1 minute or 1% IP6 for 30 seconds or 1 minute. The failed specimens were assessed under a scanning electron microscope. The reaction of NaOCl with EDTA or IP6 was analyzed in terms of temperature, pH, effervescence, and chlorine odor, and the effects of the resulting mixtures on the color of a stained paper were recorded. Results: The µTBS values of the control and NaOCl with chelator groups were not significantly different, but were all significantly higher than that of the group treated with NaOCl only. In the failure analysis, a distinctive feature was the presence of resin tags in samples conditioned with IP6 after treatment with NaOCl. The reaction of 1% IP6 with 5% NaOCl was less aggressive than the reaction of the latter with 17% EDTA. Conclusions: IP6 reversed the adverse effects of NaOCl on resin-dentin adhesion without the chlorine-depleting effect of EDTA.

• ALGAE
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• 제28권2호
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• pp.173-183
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• 2013

Sodium hypochlorite (NaOCl) is widely used to disinfect seawater in power plant cooling systems in order to reduce biofouling, and in ballast water treatment systems to prevent transport of exotic marine species. While the toxicity of NaOCl is expected to increase by ongoing ocean acidification, and many experimental studies have shown how algal calcification, photosynthesis and growth respond to ocean acidification, no studies have investigated the relationship between NaOCl toxicity and increased $CO_2$. Therefore, we investigated whether the impacts of NaOCl on survival, chlorophyll a (Chl-a), and effective quantum yield in three marine phytoplankton belonging to different taxonomic classes are increased under high $CO_2$ levels. Our results show that all biological parameters of the three species decreased under increasing NaOCl concentration, but increasing $CO_2$ concentration alone (from 450 to 715 ${\mu}atm$) had no effect on any of these parameters in the organisms. However, due to the synergistic effects between NaOCl and $CO_2$, the survival and Chl-a content in two of the species, Thalassiosira eccentrica and Heterosigma akashiwo, were significantly reduced under high $CO_2$ when NaOCl was also elevated. The results show that combined exposure to high $CO_2$ and NaOCl results in increasing toxicity of NaOCl in some marine phytoplankton. Consequently, greater caution with use of NaOCl will be required, as its use is widespread in coastal waters.

• 대한치과의사협회지
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• 제53권12호
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• pp.958-966
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• 2015

Objective: Sodium hypochlorite (NaOCl) decreases the bond strength of resin composite. The purpose of this study was to compare the effect of antioxidant and superficial dentin surface removal on the microtensile bond strength of NaOCl-treated dentin. Materials and Methods: Twenty non-carious human third molars were used in this study. The dentin surfaces were treated with 5.25% NaOCl for 10 min, followed either by treatment with 10% ascorbic acid or superficial dentin surface removal. Two-step self-etch adhesive and resin composite were used for restoration. The bonded specimens were subjected to the microtensile bond strength test. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey's test (p < 0.05). Results: The bond strength after removal of the superficial dentin surface following NaOCl irrigation was similar to that in the control group. The group treated with 10% ascorbic acid demonstrated significantly higher bond strength than the other groups. Conclusion: NaOCl irrigation-induced reduction in dentin bond strength could be recovered by either treatment with 10% ascorbic acid or simple removal of the superficial dentin surface.

• 한국환경보건학회지
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• 제35권1호
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• pp.58-63
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• 2009

This study investigated improvement to sludge dewaterability and coagulation for sewage treatment plant sludge by using sodium hypochlorite solution (NaOCl), ferric sulfate [$Fe_2(SO_4)_3$] and zeolite. The specific resistance to filtration(SRF), chloride, pH and turbidity were used to evaluate the sludge dewatering behaviors. The results of study were as follows: By varying the amount of NaOCl added the optimum result in terms of enhancement for pretreatment occurred when 34 mg/l of NaOCl was injected. When the total solids concentration of the sludge was 10,000 mg/l, the optimum ferric sulfate dosage for the sludge dewaterability was 150 mg/l and the corresponding SRF was $1.7{\times}10^7sec^2/g$. It was observed that injecting zeolite into sludge was effective in improving the dewaterability of sludge.

• The Plant Pathology Journal
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• 제35권2호
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• pp.156-163
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• 2019

Our study investigated the available chlorine content, contact time and difference among strains of each pathogen for sodium hypochlorite (NaOCl) to control chemically against soil-borne fungal pathogens, such as Phytophthora rot by Phytophthora cactorum, violet root rot by Helicobasidium mompa, and white root rot by Rosellinia necatrix, causing die-back symptom on apple trees. As a result, the colony growth of Phytophthora cactorum was inhibited completely by soaking over 5 s in 31.25 ml/l available chlorine content of NaOCl. Those of H. mompa and R. necatrix were inhibited entirely by soaking over 160 s in 62.5 and 125 ml/l available chlorine content in NaOCl, respectively. Also, inhibition effect on available chlorine in NaOCl among strains of each soil-borne pathogen showed no significant difference and was similar to or better than that of fungicides.