Lethal dose chemical

Va2o-64, ALC (approx lethal concentration) Va2o-67, LC q. Va2o-64, -52, -88, ALD (approx lethal dose) Va2o-67, LD. See text for chemical names and stmctures. 

The toxicity of many bleaching chemicals is also reflected in observed effect doses and concentrations. These measures include lowest pubHshed toxic concentration (TC q), concentration that is lethal to 50% of a specified population (LC q), lowest pubHshed lethal dose (LD q), and dose that is lethal to 50% of a specified population (LD q). Some relevant values of these are Hsted in Table 3. 

Lethal Dose 50 (LDso) A calculated dose of a chemical in water to which exposure for a specific length of time is expected to cause death in 50% of a defined experimental animal population. 

Median Lethal Dose (LD) The statistically derived single dose of a chemical that can be c.xpected to cause death in 50% of a given population of organisms under a defined set of experimental conditions. This figure has often been used to classify and compare toxicity among chemicals but its value for this purpose is doubtful. One commonly used classification of this kind is as follows ... 

Several of the commonly used rubber chemicals tike accelerators, retarders, antidegradants, etc. are classified as hazardous on account of values of LD50 (lethal dose 50%) [6]. Many of the guanidine... 

Lethal Dose(LO) (LDlq)—The lowest dose of a chemical introduced by a route other than inhalation that has been reported to have caused death in humans or animals. 

Under the Food Quality Protection Act (FQPA), the U.S. EPA evaluates the potential for people to be exposed to more than one pesticide at a time from a group of chemicals with an identified common mechanism of toxicity. As part of the examinations, to clarify whether some or all of the pyrethroids share a common mechanism of toxicity, a comparative FOB (functional observational battery) studies with 12 pyrethroids were carried out under standardized conditions [15]. The FOB was evaluated at peak effect time following oral administration of non-lethal doses of pyrethroids to rats using com oil as vehicle. Four principal components were observed in the FOB data [22], Two of these components described behaviors associated with CS syndrome (lower body temperature, excessive salivation, impaired mobility) and the others described behaviors associated with the T syndrome (elevated body temperature, tremor myoclonus). From the analysis, pyrethroids can be divided into two main groups (Type I T syndrome and Type II CS syndrome) and a third group (Mixed Type) that did not induce a clear typical response. Five other pyrethroids were also classified by an FOB study conducted in the same manner [16]. The results of these classifications are shown in Table 1. The FOB results for all non-cyano pyrethroids were classified as T syndrome, and the results of four ot-cyano pyrethroids were classified as CS syndrome however, three of the ot-cyano pyrethroids, esfenvalerate, cyphenothrin, and fenpropathrin, were classified as Mixed Type. 

The 50 percent lethal doses of ingested toxic materials that could cause fatal injury (National Institute for Occupational Safety and Health, Registry of Toxic Effects of Chemical Substances, 1983). 

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