• Journal of fish pathology
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• v.20 no.2
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• pp.161-167
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• 2007

Acute toxicity of formalin (37% formaldehyde) was conducted to determine the median lethal concentration (LC50) on eel (avarage weight 96 ± 3.6 g, average total length 43 cm), Anguilla japonica at concentrations ranging from 0 to 500 ppm. In particular, this study was designed to estimate the safety concentrations of formalin in testing eels to eradicate Pseudodactylogyrus. All fish died after 10 hours and 24 hours at 500 ppm and 400 ppm, respectively. After 24 hours, cumulative mortality was 96.6% and 13.3% at 300 ppm and 200 ppm formalin, respectively. However, all experimental fish were alive after 24 hours at 100 ppm. The lethal concentration values were computed by using non-linear least square method. At the start of the test, water temperature, pH and dissolved oxygen level were 27～28℃, 7.4 and 5.55 ppm, respectively. The 24 hr-LC50 were 269 ppm.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.139-142
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• 1984

Short-term acute toxicity of synthetic detergent(LAS) to larvae of loach, Misgurnus angillicaudatus was examined by static bioassay. The larvae were exposed to 15 different concentration of synthetic detergent for 16, 48, 72, 96 and 120 hours in order to determine median lethal concentration($LC_{50}$). The $100\%$ mortarlity of larvae was showed within 120, 96, 48 and 16 hours for 6, 18, 30 and 38 ppm, respectively. The median lethal concentration values of the larvae were 12.59 ppm for 48 hours, 4.00 ppm for 96 hours and 1.02 ppm for 120 hours. The permissible toxicant concentration of acute toxicity to larvae was $0.37{\sim}0.43$ ppm, and application factor of the synthetec detergent was $0.093{\sim}0.108$. The median lethal time($LT_{50}$) for different concentration also was determined. The $LT_{50}$ of 0.2 ppm was found within 165.1 hours and 2 ppm was 106.2 hours, while the $LT_{50}$ of 8 ppm was 60.3 hours and that of 38 ppm was 23.5 hours.

• Korean journal of applied entomology
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• v.42 no.3
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• pp.225-231
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• 2003

The susceptibility of the different larval stages of Spodoptera litura to nine insecticides was evaluated using the perilla leaf-dipping method. Median lethal concentration ($LC_{50}$) was increased with larval development in the range of 0.5 ppm to 5.6 ppm, 9.9 ppm to 27.9 ppm, 9.6 ppm to 125.1 ppm and 24.3 ppm to 546.6 ppm in the 1st, 2nd, 3rd and 4th instar, respectively. The tolerance ratio (TR), which is the TR of 90 percent lethal concentration (LC/ sub 90/) to the recommended concentration, was 0.04 to 0.8 in the 1 st, 0.2 to 7.5 in the 2nd, 0.7 to 115.3 in the 3rd and 1.2 to 485.4 in the 4th instars. Lower D$LC_{50}$ and DTR, which is the difference between the $LC_{50}$ and the TR of 4th and other instars, respectively, were observed in chlorfenapyr, chlorpyrifos and EPN while higher ones were lufenuron, chlorfluazuron and teflubenzuron. These results mean that insecticides with lower D$LC_{50}$ and DTR are effective in controlling larva of S. litura collected in Milyang, Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.599-607
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• 1986

Acute toxicity of crude oil (WSF) on the mortality and respiration rates of Neomysis awatschensis was examined. This experiment was conducted by static and short-term bioassay procedure. In lethal test, the test animals were exposured to 8 different concentrations to determine $LC_{50}$ value (median lethal concentration). The concentrations of total hydrocarbon of 96-hr $LC_{50}$ value at $14^{\circ}C\;and\;20^{\circ}C$ were 1.01 ppm and 0.78 ppm, respectively. $LT_{50}$ (the median lethal time) also was determined. The $LT_{50}$ of 0.56 ppm was found within 100 hours, while the $LT_{50}$ of 5.6 ppm was 21 hours at $14^{\circ}C$. At $20^{\circ}C$, the $LT_{50}$ values of 0.56 ppm and 5.60 ppm were 95 hours and 17 hours, respectively. There was little difference between two temperature experiments. The effect of WSF on respiration rate was more sensitive than that on mortality, but no considerable difference was shown between different concentrations in this experiment. The results of these experiments indicated that relatively low concentration of dissolved crude oil fraction can impact on small crustacean in the marine ecosystem.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.113-117
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• 1979

The short-term acute toxicities of mercury, cadmium and copper for the clam, Meretrix lusoria were determined from 28 June to 15 July, 1978. In the test with mercury and copper, the rate ot mucus excretion increased gradually at a higher concentration. But the clams did not excrete mucus in the solutions of cadmium and natural sea water. The rate of mucus excretion in mercury was $42.9\%$, and that in copper was $14.3\%$ in a test solution of 1mg/l. mercury was more toxic than copper. The median lethal concentration after 96 hours (96 hr-Lc 50) was 0.67mg/l in mercury, 7.04mg/l in copper and 7.10mg/l in cadmium. Consequently it was found that mercury was the most toxic substance and cadmium was the least. meanwhile, it was considered that exposure time by stimulation in a fixed concentration caused the test animals to respond.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.156-161
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• 1998

As grouting materials for ground improvement, silicate materials such as water glass, silica-sol and so forth are used worldwide. However, they may pollute underground water. In this study, fish poison test(Korean standard industrial code KS M 0111) which estimates toxicity for fish is applied to evaluate the toxic effect by grouting materials. From the test result of the sample made of LW, LC50(Median Lethal Concentration) reaches within 24 hours. In case of the silica-sol, it does not even in 96 hours. Therefore, we can conclude that the sililca-sol grouting method is more free from the danger of underground water pollution. From the result that the mortality of fish under the condition of pH 8.6 is 0% within 96 hours, the groundwater can be saved by controlling pH below 8.6 for the grouting in the field.

• Journal of Life Science
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• v.26 no.2
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• pp.181-189
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• 2016

The aim of this study was to identify the effects of dithiopyr (DTP), a herbicide, on behavior in zebrafish. The toxicity of DTP has rarely been investigated in fish. In the present study, zebrafish were exposed to different concentrations of DTP in the range of 10-20 μM for 48 h in a test container, in order to measure the value of median lethal concentrations (LC₅₀). Behavioral experiments were performed, including the novel tank test (NTT) and the open field test (OFT), to assess stress responses or locomotion. After exposure to the DTP solution at a sublethal concentration of 2.5–10 μM for 6 min, the behavior of the zebrafish was observed for 6 min. In the acute toxicity test, the LC₅₀ value of DTP showed as 14.49 μM in the zebrafish. The NTT showed that the duration of immobility and the velocity were significantly increased by exposure at a concentration of 5 μM of DTP, compared with a control group (p<0.05). However, compared with the control group, DTP significantly decreased the distance moved and the frequency at the top of the tank, and significantly increased the turn angle and duration at the bottom, in a concentration-dependent manner (p<0.05). In addition, in the OFT, exposure to DTP significantly decreased the distance moved and velocity compared with the control group (p<0.05). Exposure to DTP also significantly increased the duration of immobility, the turn angle, and the meandering movement, in a concentration-dependent manner (p<0.05). Further, exposure to DTP at a low concentration elevated whole-body cortisol levels in the zebrafish. The results of this study thus suggest that DTP induces a toxic response and negative effects on behavior and the endocrine system in zebrafish.

• Journal of fish pathology
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• v.22 no.1
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• pp.1-7
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• 2009

To investigate the effect of hydrogen peroxide in israel carp, Cyprinus carpio, toxicity and microbial activities were determined. For hydrogen peroxide toxicity test, the median lethal concentration ($LC_{50}$) to israel carps Cyprinus carpio (average weight 0.44 g) by acute toxicity was determined after 24 hour treatment. All israel carp were alive in 24 hours treatment at 80 $\mu\ell/\ell$ concentration and $LC_{50}$ value was 148.9 $\mu\ell/\ell$. For biocidal activities of hydrogen peroxide, remove of parasite and growth inhibition of pathogenic bacteria were determined. The parasite Trichodina sp. infected on the skin and gills of israel carps (average weight 0.1 g) was completely eliminated at 40 $\mu\ell/\ell$ of hydrogen peroxide treatment for 24 hour. Most of the minimum inhibitory concentrations (MICs) against 30 fish pathogenic bacteria were less than 40 $\mu\ell/\ell$.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.530-535
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• 2012

Polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, are released into the aquatic environment and have been identified as endocrine effects on marine organisms. Naphthalene makes up the highest fraction of PAHs in oil and shows the strong toxicity to aquatic organisms. I analyzed 24h-median lethal concentration (24h-$LC_{50}$) for juvenile olive flounder Paralichthys olivaceus to study the acute toxicity of naphthalene. Bioconcentrations in the gill, liver, kidney and muscle of olive flounder were analyzed after to 6 naphthalene concentrations of 0, 1000, 1800, 3200, 5600 and 10000 ${\mu}g/L$. Olive flounder has 24h-$LC_{50}$ value of 2410.76 ${\mu}g/L$ in Large group, and 2230.67 ${\mu}g/L$ in Samll group. Naphthalene concentration was varied with tissues. The concentrations of naphthalene were much higher in liver and kidney than in gill and muscle.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.923-929
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• 2013

Black seabream juveniles Acanthopagrus schlegelii held at $20^{\circ}C$ were exposed to formalin at concentrations of 50 to 400 ppm, and tolerance values were determined by calculating median lethal concentration values (LC50) through probit analysis. The 12-, 24, 48, 72- and 96-h LC50 values for formalin were 297, 233, 171, 162 and 157 ppm, respectively. The histological effects of formalin on gill and liver tissues in this fish were determined. No histological effects were observed in the control group. The intensity of cell damage increased with the concentration of, and duration of exposure to, formalin. Hyperplasia, separation and epithelial necrosis, epithelial lifting, lamellar synechiae and collapsed lamellae were observed in gill tissues exposed to formalin. Hepatic lesions in liver tissues of fishes exposed to formalin were characterized by cloudy swelling of hepatocytes, necrosis, cytoplasmic vacuolization, deposition of pigments, spongiosis hepatis, nuclear hypertrophy, dilation of sinusoids and bile stagnation. The LC50 values and histological results obtained in this study will aid in designing treatment regimens to minimize toxic side effects and increase efficacy.