Human lethality estimation

Previous Human Lethality Estimates for CKIH Toxieity... 

The body excretes tritium with a biological half-life of 8—14 d (10.5 d average) (75), which can be reduced significantly with forced fluid intake. For humans, the estimated maximum permissible total body burden is 37 MBq (1 mCi). The median lethal dose (LD q) of tritium assimilated by the body is estimated to be 370 GBq (10 Ci). Higher doses can be tolerated with forced fluid intake to reduce the biological half-life. 

Numerous case reports are available regarding the lethal and nonlethal toxicity of arsine in humans, but definitive exposure concentration or duration data are lacking. Although the case reports are of limited use for quantitative estimates of exposure limits, they do provide qualitative information about the nature of arsine poisoning in humans. Some estimated human toxicity values are available and are summarized in Table 2-3. 

The minimal lethal oral dose in humans was estimated to be 140 mg/kg (Bruce et al. 1987), which is similar to the lethal oral dose for a variety of animal species (see Table 2-2). Regardless of the route of administration, the sequence of events leading to death appears to be similar in a variety of animal species muscle weakness and tremors, loss of coordination, paralysis, convulsions, coma, and... 

The lethal oral dose in humans is estimated to be 0.3-0.5 g/kg. Symptoms of inhalation, absorption, or ingestion in humans (inferred mostly from animal studies) may include numbness of oral mucous membranes, nausea, vomiting, abdominal pain, muscle tremor, incoordination, clonic convulsions, and stupor. 

Most fatal cases of poisoning have been due to accidental ingestion, resulting in convulsions and death due to respiratory arrest. " The lethal oral dose for humans is estimated to be 2-7 g. ... 

Ingestion of excessive amounts of nicotine can result in nicotine poisoning, the signs and symptoms of which include pallor, diaphoresis, nausea, vomiting, salivation, abdominal pain, diarrhea, headache, dizziness, auditory and visual disturbance, tremor, confusion, and weakness. Hypotension and respiratory failure develop with large overdoses. The minimum oral acute lethal dose for nicotine in adult humans is estimated to be only 40 to 60 mg. 

Health experts advise that moderated amounts of caffeine from 100 to 300 mg per day are acceptable. Adult Americans consume approximately 250 mg of caffeine per day. The LDJ0 (the lethal dose that kills 50% of a test population of individuals subjected to a substance) of caffeine for humans is estimated between 150 and 200 mg per kilogram of body weight. The amount of caffeine in some popular food items is given in Table 18.1. 

Toxicity Methoxychlor is practically nontoxic via the oral route, with different acute oral LD50 values of 5,000 to 6,000 mg/kg in rats, 1,850 mg/kg in mice, and 2,000 mg/kg in hamsters. The lowest oral dose that can cause lethal effects in humans is estimated to be approximately 6,400 mg/kg, and the lowest dose through the skin that produces toxic effects in humans is 2,400 mg/kg based on behavioral symptoms. It reportedly is slightly to practically nontoxic dermally, with an acute dermal LD50 in rabbits of greater than 2,000 mg/kg. 

There are no reported cases of death due to inhalation of naphthalene. Naphthalene-induced deaths are usually related to mothball ingestion during suicide attempts. Based on suicide data, the lethal dose in humans is estimated to range from 319 to 574 mg kg The most prominent effect of high-dose naphthalene exposure in humans is hemolytic anemia. There is a report of an infant who died of acute hemolytic anemia after being exposed to... 

Since the 1950s, the Canadian-United States Conference on Shellfish Toxicology endorsed a mouse bioassay that was based on the use of purified toxins and has historically been the most universally applied technique for examining shellfish (especially for PSP) other bioassay procedures have been developed but not generally applied. The intraperitoneal minimal lethal dose of the toxin for the mouse was 9 pg kg body weight. The intravenous minimal lethal dose for the rabbit was 3-4pgkg body weight. The minimal lethal dose of the toxin for humans is estimated to be between 1 and 4 mg. 

Physical Properties. Pure soman is a colorless liquid with a somewhat fruity odor. It has density 1.01 g/mL (20°C), vapor pressure of 0.27 mm/Hg (20°C), mp of —80°C, and bp of 190°C (85°C at 15 mm/Hg). Distillation is accompanied by decomposition that begins near 130°C. Soman s solubility in water is about 20% at 25°C. It is only about 20% as soluble in water as is tabun. With two different chiral centers, it exists as four stereoisomers (Benschop et al., 1985), each with a different toxicity. The lethal concentration (inhalation) in humans is estimated at approximately 25-50 mg min/m (Somani et al., 1992). 

Taken together, the various estimates for human lethal toxicity to HCN vapor suggest that for an exposure of around 5 to 10 min a concentration of 500-600 mg m 3 would be fatal, but for a 1 min exposure the HCN vapor concentration would require to be around 4000 mg m 3. 

Estimates for the acute human lethal inhalation dosage for CS vary between 25 000 and 150000 mg min m-3 (WHO, 1970), but there have been no authenticated reports of death from exposure to CS smokes. The Committee of Enquiry into the use of CS in Northern Ireland concluded that the likelihood of death after inhaling an exposure dose of pyrotechnically generated smoke that is one-tenth that which would lead to death of 50% of those exposed is less than one chance in 100000, i.e. the accumulation of an inhalation exposure dose of pyrotechnically generated smoke of the order of 5000 mg min m-3 would constitute a virtually negligible risk to life. 

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