Median Lethal Concentration

Health and Safety Factors. VDE is a flammable gas its combustion products are toxic. Liquid VDE on contact with the skin can cause frostbite. Acute inhalation toxicity of VDE is low median lethal concentrations (LC q) for rats were 128,000 ppm after a single 4-h exposure (52) and 800,000 ppm after a 30-min exposure (53). Cumulative toxicity is low exposure of rats and mice at levels of up to 50,000 ppm for 90 days did not cause any... 

Median Lethal Concentration (LC) The concentration of a to.xicant lethal to one half of a test population. 

There are several significant permit conditions. As with all other OCS permits, the discharge of oil-based muds is prohibited. Similarly, the permit does not unconditionally authorize the discharge of any of the eight generic muds. Their discharge is subject to limitations on additives. To monitor the use of mud additives, the permit requires the additive not to drop or to decrease the 96-hr median lethal concentration (LC ) test below 7,400 ppm on the basis of the suspended particulate phase or 740 ppm for the whole mud. This parameter is based on a test of Generic Mud 8, which is formulated with 5% mineral oil. 

E.I.du Pont de Nemours. 1982a. Inhalation Median Lethal Concentration (LC50). OTS 84003A, Docket 878220239. E.I.du Pont de Nemours and Co., Inc., Wilmington, DE. 

The New Jersey Department of Environmental Protection uses the TXDS method of consequence analysis to estimate potentially catastrophic quantities of toxic substances, as required by the New Jersey Toxic Catastrophe Prevention Act (TCPA). An acute toxic concentration (ATC) is defined as the concentration of a gas or vapor of a toxic substance that will result in acute health effects in the affected population and 1 fatality out of 20 or less (5% or more) during a 1-hr exposure. ATC values, as proposed by the New Jersey Department of Environmental Protection, are estimated for 103 extraordinarily hazardous substances and are based on the lowest value of one of the following (1) the lowest reported lethal concentration (LCLO) value for animal test data, (2) the median lethal concentration (LC50) value from animal test data multiplied by 0.1, or (3) the IDLH value. 

SPY sulfapyridine, SDZ sulfadiazine, SMX sulfamethoxazole, SMZ sulfamethazine, SCP sulfachloropyridazine, STZ sulfathiazole, SCT sulfacetamide, AcSMX N -acetylsulfamethoxazole, AcSDM N -acetylsulfadimethoxine, AcSDZ N -acetylsulfadiazine, EC50 Median effective concentration (mg/L), LC50 Median lethal concentration (mg/L), NOEC No-observed-effect concentration (mg/L) LOEC lowest-observed-effect concentration (mg/L), h hours, min minutes, d days... 

Statistical Analysis. Analysis of variance (ANOVA) of toxicity data was conducted using SAS/STAT software (version 8.2 SAS Institute, Cary, NC). All toxicity data were transformed (square root, log, or rank) before ANOVA. Comparisons among multiple treatment means were made by Fisher s LSD procedure, and differences between individual treatments and controls were determined by one-tailed Dunnett s or Wilcoxon tests. Statements of statistical significance refer to a probability of type 1 error of 5% or less (p s 0.05). Median lethal concentrations (LCjq) were determined by the Trimmed Spearman-Karber method using TOXSTAT software (version 3.5 Lincoln Software Associates, Bisbee, AZ). 

Toxicity of many entries are expressed quantitatively as LD50 (median lethal dose) or LC50 (median lethal concentration in air). The latter refers to inhalation toxicity of gaseous substances in air. Both these terms refer to the calculated concentration of a chemical that can kill 50% of test animals when administered. 

Silver et al. reported a median lethal concentration of 1,500 g/m Tby Inhalation, for 10-min exposure of mice. 

Chloropicrin. Median lethal concentration for mice 10-min exposure. U.S. War Department, Chemical Warfare Service, Edge-wood Arsenal, Md. 1942. 8 p. 

Zhao, Y.A. and Newman, M.C. (2004) Shortcomings of the laboratory-derived median lethal concentration for predicting mortality in field populations exposure duration and latent mortality. Environ Toxicol Chem, 23, 2147-2153. 

ED 50 the median effective (therapeutic) dose - units of mg/kg body weight LDso the median lethal (fatal) dose - units of g/kg, mg/kg, mg/kg LCso the median lethal concentration - units of ppm, mg/L TDso tile median toxic dose... 

LC50 (median lethal concentration) The concentration of a test chemical that, when a population of test organisms is exposed to it, is estimated to be fatal to 50% of the organisms under the stated conditions of the test. Normally used in lieu of the LD50 test in aquatic toxicology and inhalation toxicology. 

Bonnet P, Morele Y, Raoult G, et al. 1982. Determination of the median lethal concentration of the main aromatic hydrocarbons in the rat. Arch Mai Prof 43 261-265. [French]... 

Median lethal concentration of a test material in the test matrix (e.g., growth medium) that is calculated to exhibit a lethal effect to 50% of a group of test organisms during exposure over a specified period of time. The LC50 and its 95% confidence limits are usually derived by statistical analysis of mortalities in several test concentrations. The duration of exposure must be specified (e.g., 48-h LC50). Volume 1(1,4,10), Volume 2(5). 

Median lethal concentration A statistically or graphically estimated concentration that is expected to be lethal to 50% of a group of organisms under specified conditions. See LC50. 

As an index for toxicity of gaseous substances, the median lethal concentration (LC 5 0 ) and the threshold limit value (TLV) are used to evaluate acute toxicity. LCso is the gas concentration (ppm) in air which results in the death of 50% of a population of test animals by inhalation. TLV is the threshold limit of exposure which does not cause any serious sickness in workers under normal conditions of an 8 hours day and a 40-48 hour work week. TLV is usually given in combination with the time-weighted-average concentrations for 8 hours per day (TLV—TWA), or with the short time exposure limit (TLV-STEL), which is that exposure which should not be exceeded even for a relatively short period (15-30 minutes), or with the ultimate limit (TLV-C), which defines the exposure level that should not be exceeded under any circumstances. 

Abbreviations LC, median lethal concentration LOAEL, lowest observable adverse effect level NOAEL, no observable adverse effect level NS, not specified. 

Silver, S.D., and F.P.McGrath. 1942. Chlorine Median Lethal Concentration for Mice. Tech. Rep. 351. Edgewood Arsenal, MD War Dept., Chemical Warfare Service. 14 pp. May 9. 

Abbreviations LQgi median lethal concentration ppm, pans per million. 

Abbreviations LC50, median lethal concentration LD50, median lethal dose ppm, parts per million. 

Abbreviations HAL, bronchoalveolar lavage LQo, median lethal concentration LDH, lactic dehydrogenase LOAEL, lowest observed adverse effect level NOAEL, no observed adverse effect level NR, not reported VE, minute volume of ventilation. 

The dose at which only 50% of the organisms remain alive is the median lethal dose LD50). The equivalent for inhaled toxicants is the median lethal concentration (LCgo), where the dose is expressed as the concentration of the substance present in the inhaled air. 

Acute inhalation toxicity can be conducted in an exposure chamber. It is recommended, but not required, that nose-only or head-only exposure be used for aerosol studies to minimize oral exposures due to animals licking compound off their fur. For nongaseous pesticides, introduction of the sample in the form of mist or dust becomes a necessity. The animals are exposed for 4 hr and then transferred to other containers for observations for at least 14 d. The median lethal concentration obtained is referred to as inhalation LC30 (Anonymous, 1998). 

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