• Korean Journal of Environmental Biology
• /
• v.23 no.1
• /
• pp.89-92
• /
• 2005

The effect of cement on survival, LC/sub 50/, safe concentration (SC) and application factors of pollutant (AF) for pond smelt, Hypomesus olidus were investigated for 96 hours. Mean body length of pond smelt used in this experiment was 8.6±1.2 cm. Cement concentrations established in this experiment were 0 (control group), 10, 25, 50, 100, 250, 500, and 1,000 ppm, respectively. All fishes were dead in concentration more than 500 ppm cement within 4 hours. The LC/sub 50/ to cement toxicity was 123.03 ppm for 48h, 91.20 ppm for 72 h and 58.88 ppm for 96h. The value of SC and AF to cement toxicity for this species were 2.64∼9.14 ppm and 0.045∼0.155, respectively.

• Korean journal of applied entomology
• /
• v.40 no.3
• /
• pp.245-252
• /
• 2001

Entomopathogenic nematodes were effective in the control of the cotton caterpillar, Palpita indica Saunder. P. indica mortality was significantly different depending on nematode species, treatment concentration, and instar. S. carpocapsae Pocheon strain was more effective against P. indica than S. glaseri Dongrae strain, S. longicaudum Nonsan strain, Heterorhabditis sp. Gyeongsan isolate, and H. bacteriophora Hamyang strain. When S. carpocapsae was treated with the rate of > 20 infective juveniles (ijs)/larva, mortality was ca. 100% at the 1st-4th instars of P. indica in 72h. $LC_{50}$ of entomopathogenic nematodes were significantly different depending on nematode species. The lowest $LC_{ 50}$ value was obtained by S. carpocapsae with 4.9-8.2 ijs in the 1st-prepupa while the highest $LC_{50}$ by Heterorhabditis sp. with 5.5-21.9 ijs, the shortest LT$_{50}$ value of P. indica was induced by S. carpocapsae when 20 ijs/larva were inoculated. The $LT_{50}$ s were 3.4-9.2h against the 1st-prepupa. The mortality of P. indica in fields was significantly different depending on field condition, nematode concentration, and leaf location. Mortality of P. indica by S. carpocapsae was higher at greenhouse,$ 3$\times$10^{9}$ ijs/ha and upper leaves than at field, 1$\times$10$^{9}$ ijs/ha and lower and middle leaves, respectively.

• Korean journal of applied entomology
• /
• v.42 no.3
• /
• pp.225-231
• /
• 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
• /
• v.29 no.1
• /
• pp.124-133
• /
• 1996

A herbivorous copepod, Tigriopus japonicus, was tested to study its acute and chronic responses to Cd tonicity. Under $20^{\circ}C,\;96hr-LC_{50}$ of T. japonicus in medium with $32\%_{\circ},\;26\%_{\circ},\;and\;18\%_{\circ}$ salinity were 11.1 ppm, 13.7 ppm, and 9.7 ppm, respectively. The $96hr-LC_{50}$ in medium with $32\%_{\circ},\;26\%_{\circ},\;and\;18\%_{\circ}$ salinity increased to 21.6 ppm, 15.0 ppm, and 11,0 ppm, respectively under $10^{\circ}C$ condition. Oxygen consumption rates during 96hrs exposure to Cd toxicity decreased more sharply at $20^{\circ}C$ than those at $10^{\circ}C$. Survival rate and $250dys-LC_{50}$ of T. japonicus in medium with $32\%_{\circ}$ salinity, in concentration of Cd 4 ppm were $5\%$ and 0.05 ppm, respectively under $10^{\circ}C$, and $0\%$ and 0.20 ppm under $20^{\circ}C$. It was that the copepod selectively feed on Skeletonema costatum, Nitzschia pungens, N. seriata, and Rhizosolenia hebetata f. semispina.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.1
• /
• pp.87-97
• /
• 1995

Acute and chronic toxicity of phenol on the mortality, long-term survival and respiration rates of the mysid, Archaeomysis kokuboi adult and juvenile were examined. This experiment was condurted by static bioassay procedure with the different salinity at $25^{\circ}C$ In lethal test, the test animals were exposed to 6 different phenol concentrations to determine $LC_{50}$ and I$LT_{50}$ (median lethal concentration and time) values. The $LC_{50}$ values with the exposure time for the mysid adult ranged from 31.31ppm to 1.49ppm phenol and for the mysid juvenile ranged from 6.90ppm to 0.26ppm in all experimental groups. Mortality was increased with the decrease of salinity, The $96hr-LC_{50}$ values at 16, 24 and $32\%o$ salinity for the mysid adult were 1.49, 2.71 and 4.53ppm phenol, white the values for the mysid juvenile were 0.26, 0.56 and 0.71ppm, respectively. The ratios of $96hr-LC_{50}$ values for the mysid adult to those for the mysid juvenile at 16, 24 and $32\%p$ salinity were 5.73, 4.84 and 6.38, respectively. The mysid juveniles were more sensitive to phenol than the mysid adults. Compared $LT_{50}$ values for the mysid adult with those for the mysid juvenile, the $LT_{50}$ values for the mysid adult ranged from 384.7 to 29.0 hours at 1.7-127ppm phenol concentrations and for the mysid juvenile ranged from 132.2 to 18.7 hours at 0.5~6.Oppm phenol concentrations. The lowest $LT_{50}$ values for the mysid adult and juvenile were showed at the combination of the highest experimental concentration of phenol and the lowest experimental salinity. The mysid juveniles showed lower $LT_{50}$ values than those of adults. The chronic effects of phenol on the mysid at the sublethal effective concentration of phenol were lower in the $32\%o$ salinitr group than 16 or $24\%o$ salinity groups. Oxygen consumption rates of the mysid adult were decreased with the increase of phenol concentration and exposure time, and decreased significantly in lower salinity at the same concentration or phenol.

• Korean journal of applied entomology
• /
• v.32 no.2
• /
• pp.129-133
• /
• 1993

The German cockroach (Blattella germanical L.) populations were successively selected with chlorpyrifos and permethrin for xis generations. The resulting resistant strains, $R_{chlorpyrifos}$(Rc) and $R_{permethrin}$(Rp) were observed resistant development and the cross-resistance. The result indicated that the values of $LC_{50}$ were increased 3.32 and 2.10 times from the susceptible strain, respectively. In the Rc strains, the values of the $LC_{50}$ of fenvalerate, propoxur, permethrin were to 3.89, 2.97, and 1.31 times higher than that of the suseptible, respectively. In the Rp strains, the values of the $LC_{50}$ of fenvalerate, chlorpyrifos, and propoxur showed 5.23, 1.42, and 1.80 times cross-resistance.

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

• KSBB Journal
• /
• v.20 no.2 s.91
• /
• pp.84-87
• /
• 2005

Toxicity test for biodiesel (BD), biodiesel-derived neopentyl polyol ester (NPE) lubricant oil base, lubricant oil for diesel engine oil (LODE) and petroleum diesel (PD) was carried out using earthworm, Eisenia fefida. According to the method by OECD 207, the $LC_{50}$ values of BD and NPE were estimated as 2,450 and 1,528 mg/kg, respectively, which indicate that these compounds are classified as slightly toxic compounds. The $LC_{50}$ values of LODE and PD were estimated as 500 and 603mg/kg, respectively, showing that theses compounds are evaluated as moderately toxic compounds.

• Proceedings of the KAIS Fall Conference
• /
• 2004.06a
• /
• pp.311-314
• /
• 2004

Toxicity test fur various synthetic lubricant oil bases derived from biodiesel was carried out. The earthworms(Eisenia fetida) were maintanied in artificial soil consisting of sand for 14 days. Eisenia fetida was cultivated at temperature of $20{\pm}2^{\circ}C$, pH 6.0 $\pm$ 0.5 and moisture of $31\~37\%$. Pentaerythritol(PE) lubricant oil base was tested for acute toxicities to Eisenia fetida. The earthworms were exposed to each lubricant oil with various concentrations of lubricant oil base. After 14 days, the number of surviving earthworms and thier weight alteration during the test period was determined. $LC_{50}$(lethal concentration when $50\%$ of the population were killed) pentaerythritol was determined to be 1,555 mg/kg soil dry weight.

• Journal of Marine Life Science
• /
• v.7 no.2
• /
• pp.129-138
• /
• 2022

Crucian carp, Carassius carassius (Weight 42.4 ± 9.0 g, Length 15.0 ± 1.0 cm) were exposed to waterborne zinc at 0, 5, 10, 20, 40 and 80 mg Zn²⁺/l for 96 hours. The lethal concentration 50 (LC₅₀) at 96 hours of crucian carp, C. carassius exposed to waterborne zinc was 51.58 mg Zn²⁺/l. In hematological parameters, the RBC count was significantly decreased in the concentration of 40 mg Zn²⁺/l at 48 hours, whereas the hematocrit was significantly increased by zinc exposure. The MCV (mean corpuscular volume) (µl) and MCH (mean corpuscular hemoglobin) (pg) were significantly increased in the concentration of 40 mg Zn²⁺/l at 48 hours. The plasma components such as calcium, magnesium, glucose, cholesterol, total protein and ALT (Alanine aminotransminase) were significantly changed by zinc exposure. The results of this study suggest that the zinc exposure to C. carassius induced the significant physiological changes in the hematological parameters and plasma components as toxicity.